2025/06/05 更新

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写真a

アハメド アブドラハマンザカリア
AHMED ABDELRAHMAN ZKRIA
AHMED ABDELRAHMAN ZKRIA
所属
総合理工学研究院 准教授
総合理工学研究院 IFC部門(併任)
総合理工学府 総合理工学専攻(併任)
職名
准教授
連絡先
メールアドレス
電話番号
0925837783
プロフィール
私の研究は、アークプラズマ、パルスレーザー蒸着、RF/DCスパッタリングなどの物理蒸着法(PVD)を用いた炭素系ナノ材料および薄膜の成膜プロセスの開発に焦点を当てています。特に、ナノダイヤモンド薄膜の成長とその応用について、半導体デバイス、防食コーティング、医療用インプラント、CO₂変換システムなど、幅広い分野に向けた研究を行っています。さらに、ガリウム酸化物/ダイヤモンドのヘテロ構造形成にも取り組んでいます。また、エネルギー関連分野への応用を目的として、エレクトロスピニング法による高分子/ナノダイヤモンド複合ナノファイバーの開発にも取り組んでいます。
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研究分野

  • ナノテク・材料 / ナノ材料科学

  • ナノテク・材料 / 薄膜、表面界面物性

  • 自然科学一般 / 半導体、光物性、原子物理

  • ものづくり技術(機械・電気電子・化学工学) / 電気電子材料工学

  • ナノテク・材料 / 薄膜、表面界面物性

学位

  • Ph.D. in Applied Physics ( 2017年9月 九州大学 )

  • Master in Physics ( 2012年5月 Aswan University, Egypt/ Graz University, Austria )

  • Bachelor in Science ( 2006年7月  South Valley University, Egypt )

経歴

  • 九州大学 総合理工学研究院 助教授 准教授

    2024年2月 - 現在

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    国名:日本国

  • 九州大学 日本・エジプト科学技術連携センター 大学院担当助教 特任助教

    2020年4月 - 2023年12月

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    国名:日本国

  • National Taiwan University Department of Material Science and Engineering 客員准教授 

    2025年2月 - 2025年3月

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    国名:台湾

  • 九州大学 日本・エジプト科学技術連携センター 特任准教授 

    2023年1月 - 2024年1月

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    国名:日本国

  • North Carolina State University Department of Material Science and Engineering 学術研究員 Visiting Scientist

    2018年11月 - 2019年3月

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    国名:アメリカ合衆国

  • 九州大学 総合理工学研究院 学術研究員 特別研究員

    2017年11月 - 2019年11月

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    国名:日本国

▼全件表示

学歴

  • 九州大学   Department of Applied Sciences for Electronics and Materials   Ph.D.

    2014年4月 - 2017年9月

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    国名:日本国

  • Graz University   Nanophysics   MSc

    2011年9月 - 2010年9月

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    国名:オーストリア共和国

  • Aswan University   Physics Department   Master in Science

    2008年8月 - 2012年4月

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    国名:エジプト・アラブ共和国

  • South Valley University   Physics Department   Bachelor in Sciences

    2002年9月 - 2006年5月

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    国名:エジプト・アラブ共和国

研究テーマ・研究キーワード

  • 研究テーマ: 防食コーティング、インプラント、CO₂還元、燃料電池スタックなど、さまざまな応用に向けた新たな炭素系材料の探索を行っています。

    研究キーワード: 炭素系材料、アークプラズマ、薄膜、防食コーティング、CO2 還元, バイオマテリアル, インプラント, DCスパッタリング, 酸化ガリウム, メンブレン 技術, エレクトロスピニング, 水処理

    研究期間: 2024年11月 - 現在

  • 研究テーマ: 物理的気相成長法を用いた電子応用のためのカーボンナノ材料の合成

    研究キーワード: 炭素系材料、アークプラズマ、薄膜、電子応用、ダイヤモンドデバイス

    研究期間: 2022年4月 - 現在

  • 研究テーマ: ダイヤモンド表面のレーザー誘起ドーピングと修飾

    研究キーワード: ナノ秒レーザー, ダイヤモンド

    研究期間: 2017年10月 - 2021年9月

  • 研究テーマ: 電子デバイス応用に向けたRFスパッタリング法による酸化ガリウムの成膜

    研究キーワード: RFスパッタリング 酸化ガリウム ダイヤモンド フォトダイオード

    研究期間: 2024年2月 - 現在

  • 研究テーマ: エネルギー応用に向けたエレクトロスピニング法による新規高分子複合材料の開発

    研究キーワード: 膜技術 エレクトロスピニング スーパーキャパシタ

    研究期間: 2024年10月 - 現在

  • 研究テーマ: 超高結晶ダイヤモンド/水素化アモルファスカーボン複合体(UNCDa/-C:H)膜のフォトダイオードおよび太陽電池への応用

    研究キーワード: 超高結晶ダイヤモンド, UNCD, フォトダイオード, フォトビルタイクス, 太陽電池

    研究期間: 2017年11月 - 2019年12月

  • 研究テーマ: 物理的気相成長法による窒素ドープナノダイヤモンド膜の成長。

    研究キーワード: Nanodiamond

    研究期間: 2014年4月 - 2017年9月

受賞

  • Watanabe Trust Award for Academic Staff

    2025年5月   Watanabe Trust Fund   Watanabe Trust Award for Academic Staff

    Abdelrahman Zkria Ahmed

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    受賞区分:国内外の国際的学術賞  受賞国:アイスランド共和国

    The Watanabe Fund supports students and academic staff from all disciplines at the University of Iceland for studies and research in Japan, and the same applies to students and researchers from Japanese universities who wish to study or conduct research at the University of Iceland.

  • University Academic Alliance in Taiwan (UAAT) Young Scholar Award

    2024年10月   University Academic Alliance in Taiwan (UAAT)   UAAT International Young Visiting Scholar Program for 2024

    Abdelrahman Zkria Ahmed

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    受賞区分:国内外の国際的学術賞  受賞国:台湾

    UAAT established this fellowship to promote collaboration between outstanding young scholars from international partner university alliances/systems. The program encourages cooperation in research, teaching, and innovation & entrepreneurship (I&E) to strengthen international talent exchange and boost academic research and innovation.

  • Kyushu University International Meeting Award

    2017年4月   Kyushu University   Kyushu University International Meeting Award

    Abdelrahman Zkria Ahmed

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

    Award from Kyushu University (500,000JPY) for student’s excellency to join an international conference abroad [11th Int. conf. New Diamond and Nano Carbon (NDNC), Cairns, Australia]

  • Kyushu University International Meeting Award

    2014年4月   Kyushu University   Kyushu University International Meeting Award

    Abdelrahman Zkria Ahmed

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    受賞区分:国内学会・会議・シンポジウム等の賞  受賞国:日本国

    Award from Kyushu University (500,000JPY) for student’s excellency to join an international conference abroad [Material Research Society (MRS-2014)-Fall, Boston, USA]

論文

  • Thermal Stability of β-Ga₂O₃/Diamond (111) Heteroepitaxial Structures Grown by RF Magnetron Sputtering 査読

    Y. Wang, M. Sreenath, Y.Katamune, I. Misono, I. Yuto, H.Naragino, P.Sittimart, A. Zkria, T. Yoshitake

    Materials Letters   396   2025年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi.org/10.1016/j.matlet.2025.138753

  • Novel eco-friendly nanodiamonds@ chitosan hybrid microcapsules via facile electrospraying for self-healing and anticorrosion coating 国際共著

    Lydia Uko, H. Noby, A. Zkria, M. ElKady

    Diamond and Related Materials   2024年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi.org/10.1016/j.diamond.2024.111436

  • Fabrication of nitrogen-doped quenched-produced diamond electrodes on titanium substrates by coaxial arc plasma deposition 査読

    S. Nagano, H. Naragino, H. Hashiguchi, S. Hokazono, L. Osman, M. Diab, A. Zkria, T. Yoshitake

    Functional Diamond   4 ( 1 )   2024年10月

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    掲載種別:研究論文(学術雑誌)  

    DOI: doi.org/10.1080/26941112.2024.2418587

  • Engineered eco-friendly composite membranes with superhydrophobic/hydrophilic dual-layer for DCMD system 査読 国際共著

    MM Sayed, H Noby, A. Zkria, HM Mousa, T Yoshitake, M ElKady

    Chemosphere   2024年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi.org/10.1016/j.chemosphere.2024.141468

  • Heteroepitaxial growth of β-Ga2O3 thin films on single crystalline diamond (111) substrates by radio frequency magnetron sputtering 査読 国際誌

    akafumi Kusaba, Phongsaphak Sittimart, Yuki Katamune, Taisuke Kageura, Hiroshi Naragino, Shinya Ohmagari, Sreenath Mylo Valappil, Satoki Nagano, Abdelrahman Zkria, Tsuyoshi Yoshitake

    Applied Physics Express   2023年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In this work, we demonstrate the first achievement in heteroepitaxial growth of β-Ga2O3 thin films on single crystalline diamond (111) wafers using RF magnetron sputtering. A single monoclinic (β-phase) structure with a monofamily {01} plane was obtained. XRD pole figure shows (02) and (002) textures of the (01) β-Ga2O3 plane parallel to (111) diamond with six distinct rotational domains, confirming successful epitaxial growth. Collectively, this research provides valuable insights into the epitaxial growth of β-Ga2O3 on diamond via sputtering, paving the way for scalable β-Ga2O3/diamond heterostructures for future electronic and optoelectronic applications with not only high performance but also effective self-thermal management.

    その他リンク: https://iopscience.iop.org/article/10.35848/1882-0786/acfd07/meta

  • Overcoming the impact of post-annealing on uniformity of diamond (100) Schottky barrier diodes through corrosion-resistant nanocarbon ohmic contacts 招待 査読 国際誌

    Sreenath Mylo Valappil, Abdelrahman Zkria, Shinya Ohmagari, Tsuyoshi Yoshitake

    Materials Research Express   2023年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Adhesion of nanodiamond composite films on Ti substrates at room temperature via hybrid ion etching gun and coaxial arc plasma deposition 招待 査読 国際誌

    Lama Osman, Ali M Ali, Abdelrahman Zkria, Hiroshi Naragino, Tsuyoshi Yoshitake

    Applied Physics Express   15   115004   2022年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    It has been extremely difficult for nanodiamond composite (NDC) films to be deposited on Ti due to a large thermal expansion coefficient difference. The native oxide layer on Ti is another problem preventing the appropriate adhesion of NDC films and subsequent delamination. In this work, innovative room temperature adhesion of 3 μm NDC films with 54 GPa hardness on Ti substrates was accomplished via a hybrid system of ion etching gun and coaxial arc plasma deposition (CAPD). Ar+ plasma etching is capable to terminate the superficial TiO 2 layer and manipulates substrate morphology during CAPD provides instantaneous deposition of NDC films at room temperature.

  • Formation of p-n+ diamond homojunctions by shallow doping of phosphorus through liquid emersion excimer laser irradiation 招待 査読 国際誌

    Eslam Abubakr, Shinya Ohmagari, Abdelrahman Zkria, Hiroshi Ikenoue, Julien Pernot, Tsuyoshi Yoshitake

    Materials Research Letters   2022年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1080/21663831.2022.2083457

  • Laser-induced novel ohmic contact formation for effective charge collection in diamond detectors 招待 査読 国際誌

    Eslam Abubak, ShinyaOhmagar, Abdelrahman Zkria, Hiroshi Ikenoue, and Tsuyoshi Yoshitake

    Materials Science in Semiconductor Processing   2022年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In this study, we employed an authentic process for the device fabrication of diamond detectors, wherein thin, highly conductive surface layers were processed in bulk diamond substrate using a nanosecond-pulsed excimer laser with liquid-immersion irradiation. The incorporation of high-concentration phosphorus dopants at 40 nm under the irradiated surface characterized the irradiated areas with much lower electrical resistivity, which was adequate for demonstrating ohmic contacts even with the tungsten probe heads at room temperature.

    DOI: https://doi.org/10.1016/j.mssp.2021.106370

  • Laser-induced phosphorus-doped conductive layer formation on single-crystal diamond surfaces 招待 査読 国際誌

    Eslam Abubakr, Abdelrahman Zkria, Shinya Ohmagari, Yu̅ki Katamune, Hiroshi Ikenoue, Tsuyoshi Yoshitake

    ACS Applied Materials & Interfaces   2020年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1021/acsami.0c18435

  • Impedance spectroscopy analysis of n-type (nitrogen-doped) ultrananocrystalline diamond/p-type Si heterojunction diodes 招待 査読 国際誌

    Abdelrahman Zkria, Mahmoud Shaban, Eslam Abubakr, Tsuyoshi Yoshitake

    Physica Scripta   95 ( 9 )   2020年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Heterojunction diodes are constructed by growing n-type (nitrogen-doped) ultrananocrystalline diamond (UNCD)/hydrogenated amorphous carbon (a-C:H) composite films onto p-type Si substrates in nitrogen and hydrogen mixed-gases by coaxial arc plasma deposition. The fabricated heterojunctions are analyzed regarding their film morphology and electrical properties. The complex structure of UNCD/a-C:H films, which consists of nano-sized-sp3 diamond grains and sp2-grain boundaries (GBs), makes it difficult to separate their contribution to electrical conductivity of the films using conventional characterization methods. In this paper we characterize the n-type UNCD/p-type Si heterojunction diode by employing impedance spectroscopy method, which can isolate the differing components that contribute to the overall conductivity of the film. The impedance spectroscopy is measured in the frequency range of 100 Hz to 2 MHz, with AC small signal superimpose on DC bias voltage in the range of 0–1 V. The influence of the bias on UNCD grains and GBs contribution to resistance and capacitance of UNCD/a-C:H film and n-UNCD/p-Si heterojunction is investigated by equivalent circuit model using fitting of the impedance data. The results revealed that the electrical conductivity is mainly controlled by the GBs rather than the UNCD grains. Furthermore, the extracted value of dielectric constant of N-doped UNCD/a-C:H film is found to be comparable with that of microcrystalline diamond, which indicates the capacitance contribution in the device is mainly originated from the UNCD grains. This study demonstrates capability of impedance spectroscopy to provide an obvious separated contribution of sp3 and sp2 bonded carbons to the electrical conductivity in their coexistence materials.

    DOI: https://doi.org/10.1088/1402-4896/aba97e

  • Structural evolution of laser-irradiated ultrananocrystalline diamond/amorphous carbon composite films prepared by coaxial arc plasma 招待 査読 国際誌

    Abdelrahman Zkria, Mohamed Egiza, Ariful Haque, Eslam Abubakr, Jagdish Narayan, Tsuyoshi Yoshitake

    Applied Physics Express   ( Applied Physics Express, Volume 13, Number 10 )   2020年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: DOI 10.35848/1882-0786/abb871

  • Structural evolution of laser-irradiated ultrananocrystalline diamond/amorphous carbon composite films prepared by coaxial arc plasma 招待 査読 国際誌

    Abdelrahman Zkria, Mohamed Egiza, Ariful Haque, Eslam Abubakr, Jagdish Narayan, Tsuyoshi Yoshitake

    Applied Physics Express   ( Applied Physics Express, Volume 13, Number 10 )   2020年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Ultrananocrystalline diamond/hydrogenated amorphous carbon films were synthesized by coaxial arc plasma deposition. The morphological and structural evolutions of the films driven by laser irradiation (ArF, 193 nm, 20 ns) are examined at different laser energies (0.4–1 J cm−2). Up on laser irradiation, the films revealed hydrogen effusions accompanied by the transformation of sp3 into sp2-hybridization carbon. However, the film irradiated at 0.8 J cm−2 exhibited higher sp3 fractions, which can be attributed to that: a specific value of laser energy density (0.8 J cm−2) can provide a suitable amount of heating that is enough to quench the film and increase the sp3 contents.

    DOI: DOI 10.35848/1882-0786/abb871

  • Laser-induced structure transition of diamond-like carbon coated on cemented carbide and formation of reduced graphene oxide 招待 査読 国際誌

    @Abdelrahman Zkria, Ariful Haque, #Mohamed Egiza, #Eslam Abubakr, #Koki Murasawa, @Tsuyoshi Yoshitake, Jagdish Narayan

    MRS Communications   1 - 6   2019年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    We report on the structural evolution of diamond-like carbon (DLC) films by the nanosecond pulsed laser annealing process. DLC film is coated on cemented carbide (WC-Co) by cathodic arc ion plating, which is then annealed by ArF laser (193 nm, 20 ns) at different laser fluences (0.9–1.7 J/cm2). Upon laser annealing, Raman spectra divulge higher sp3 fractions accompanied by a blue shift in the G-peak position, which indicates the changes of sp2 sites from rings to chains. At higher fluence (>1.2 J/cm2), the film converts into reduced graphene oxide confirmed by its Raman-active vibrational modes: D, G, and 2D.

    DOI: DOI: https://doi.org/10.1557/mrc.2019.88

  • Formation of low resistivity layers on singlecrystalline diamond by excimer laser irradiation 招待 査読 国際誌

    #Eslam Abubakr, @Abdelrahman Zkria, Yūki Katamune, Shinya Ohmagari, @Kaname Imokawa, @Hiroshi Ikenoue, @Tsuyoshi Yoshitake

    Diamond and Related Materials   95   166 - 173   2019年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A singlecrystalline diamond (100)(Ib) plate immersed in 2% boric acid was irradiated by 193-nm ArF excimer laser beams for the formation of conductive layers on the surface of an insulating diamond substrate. From current-voltage measurements of the irradiated areas, it was confirmed that semiconducting layers with high conductivities are formed on the diamond surface. It was possible to form ohmic contacts by directly touching tungsten probes with the layer surface. Since Raman spectra exhibited only peaks due to diamond and no peaks due to amorphous carbon, the drastically enhanced conductivity is not attributed to amorphous carbon formation but due to the incorporation of boron atoms into the diamond subsurface from the dopant acid. Secondary ion mass spectrometric depth profile showed the incorporation of boron atoms up to 40 nm depths from the surface. From cathodoluminescence measurements at low temperatures, it was difficult to detect clear peaks for the substitutional incorporation of boron atoms into diamond lattices, which could be attributed to the small thickness of the doped layer for detection. The proposed technique is a new potential method for shallow doping and formation of conductive layers on singlecrystalline diamond surfaces.

    DOI: 10.1016/j.diamond.2019.04.013

  • Optical and structural characterization of ultrananocrystalline diamond/hydrogenated amorphous carbon composite films deposited via coaxial arc plasma 招待 査読 国際誌

    Abdelrahman Zkria, Fouad Abdel-Wahab, Yuki Katamune, Tsuyoshi Yoshitake

    Current Applied Physics   2019年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Ultrananocrystalline diamond/hydrogenated amorphous carbon composite films were deposited in the ambient of hydrogen by coaxial arc plasma deposition. The film compositions and chemical bonding structures were investigated by X-ray diffraction, X-ray photoemission and hydrogen forward scattering spectroscopies. The sp3/(sp2+sp3) ratio and hydrogen content in the film were estimated to be 64% and 35 at.%, respectively. The optical parameters and the optical dispersion profile were determined by using a variable angle spectroscopic ellipsometer at 55°, 65° and 75° angle of incidence in the photon energy range of 0.9–5 eV. Combinations of multiple Gaussian, and Tauc-Lorentz or Cody-Lorentz dispersion functions are used to reproduce the experimental data. Results of ellipsometry showed a refractive index of approximately 2.05 (at 2eV) and optical band gap of 1.63 eV. The imaginary part of dielectric function exhibited a peak at 3.8 eV, which has assigned to π-π* electron transitions. Furthermore, Electron spin resonance measurements implied the existence of dangling bonds, which might have a partial contribution to the optical absorption properties of the deposited films. A correlation between optical parameters and structural profile of the deposited films is discussed.

    DOI: https://doi.org/10.1016/j.cap.2018.11.012

    その他リンク: https://www.sciencedirect.com/science/article/pii/S1567173918303171

  • Temperature-dependent current–voltage characteristics and ultraviolet light detection of heterojunction diodes comprising n-type ultrananocrystalline diamond/hydrogenated amorphous carbon composite films and p-type silicon substrates 招待 査読 国際誌

    Abdelrahman Zkria, Tsuyoshi Yoshitake

    Japanese journal of applied physics   2017年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Heterojunction diodes comprising poorly (1 at. %) nitrogen-doped n-type ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/a-C:H) films and p-type Si substrates were prepared in nitrogen and hydrogen mixed gas atmosphere by coaxial arc plasma deposition. Dark current density–voltage (J–V) characteristics were studied in the temperature range of 200–400 K, in order to investigate the current transport mechanism through the fabricated heterojunctions. The temperature dependence of the ideality factor and reverse saturation current reveals that carrier transport predominantly occurs in the generation–recombination mechanism and, at low temperatures, it accompanies tunneling via weak traps. The heterojunctions surely exhibited photodetection for 254 nm ultraviolet light illumination. It is expected that photocarriers will be generated at UNCD grains and transported through an a-C:H matrix.

    DOI: DOI 10.7567/JJAP.56.07KD04

  • Application of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films for ultraviolet detection 招待 査読 国際誌

    #Abdelrahman Zkria, #Hiroki Gima, @Tsuyoshi Yoshitake

    Applied Physics A: Solids and Surfaces   123 ( 3 )   2017年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon (UNCD/a-C:H) films were grown by coaxial arc plasma deposition in the ambient of nitrogen and hydrogen mixed gases. Synthesized films were structurally investigated by X-ray photoemission and near-edge X-ray absorption fine structure spectroscopies. A heterojunction with p-type Si substrate was fabricated to study the ultraviolet photodetection properties of the film. Capacitance–voltage measurements assure the expansion of a depletion region into the film side. Current–voltage curves in the dark showed a good rectifying behaviour in the bias voltages range between ±5 V. Under 254 nm monochromatic light, the heterojunction shows a capability of deep ultraviolet light detection, which can be attribute to the existence of UNCD grains. As the diode was cooled from 300 K down to 150 K, the detectivity has a notable …

    DOI: 10.1007/s00339-017-0798-4

  • Electrical characteristics of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by coaxial arc plasma deposition 招待 査読 国際誌

    Abdelrahman Zkria, Hiroki Gima, Mahmoud Shaban, Tsuyoshi Yoshitake

    Applied Physics Express   2015年8月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Nitrogen-incorporated ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/aC: H) films were synthesized in nitrogen and hydrogen mixed gas atmospheres by coaxial arc plasma deposition. The temperature dependence of electrical resistivity implies that carriers are transported in hopping conduction. Heterojunctions comprising 3 at.% nitrogen-doped films and p-Si substrates exhibited a typical rectifying action. The expansion of a depletion region into the film side was confirmed from the capacitance–voltage characteristics, and the built-in potential and carrier concentration were estimated to be 0.51 eV and 7.5× 10 16 cm− 3, respectively. It was experimentally demonstrated that nitrogen-doped UNCD/aC: H is applicable as an n-type semiconductor.

    DOI: DOI 10.7567/APEX.8.095101

  • Thermal annealing effects on β-Ga<inf>2</inf>O<inf>3</inf>/diamond (111) heteroepitaxial structures fabricated by radio frequency magnetron sputtering

    Wang Y., Valappil S.M., Katamune Y., Misono I., Ikegami Y., Naragino H., Sittimart P., Zkria A., Yoshitake T.

    Materials Letters   396   2025年10月   ISSN:0167577X

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    出版者・発行元:Materials Letters  

    Heteroepitaxial integration of β-Ga2O3 on diamond (111) has been achieved using radio frequency magnetron sputtering. The β-Ga2O3 epilayer exhibited a high level of in-plane stacking with {-201} parallel to diamond {111}, as confirmed by X-ray diffraction analyses. Pole figure stereographic projections effectively concluded the inoccupancy of (101) texture in the β-Ga2O3 film. The heterojunction preserved its mechanical integration, crystallinity, and heteroepitaxial characteristics up to 900 °C thermal annealing for 40 min. However, annealing at 1000 °C led to structural degradation, attributed to thermal graphitization at the C–O interface. Notably, post-fabrication thermal annealing at 900 °C significantly reduced the oxygen vacancy density in the β-Ga2O3 epilayer from 24.15 % to 15.07 %.

    DOI: 10.1016/j.matlet.2025.138753

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  • Nuclear magnetic resonance spectroscopy: A comprehensive tool for analyzing liquid products in electrochemical CO<inf>2</inf> reduction

    Abu Hatab A.S., Ahmad Y.H., Mady M.F., Hassan Y., Zkria A., Sinopoli A., Abdullah A.M., Al-Qaradawi S.Y., Yoshitake T., Khaled M.

    Journal of Electroanalytical Chemistry   986   2025年6月   ISSN:15726657

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    出版者・発行元:Journal of Electroanalytical Chemistry  

    The electrochemical reduction of carbon dioxide (eCO2RR) has become a very promising pathway that can be used in the transformation of CO2 to important chemical products and, thus, is one of the mitigations of climate change and will contribute toward sustainable chemical production. This review aims at presenting the importance of Nuclear Magnetic Resonance spectroscopy (NMR) to analyze and quantify the liquid-phase products obtained by eCO2RR. This provides a summary regarding the role that NMR plays in the process of reducing carbon dioxide. The following discusses the benefits: identification, complete elucidation, and follow-up on reactions involving CO2 electro-reduction. Pulse experiments corresponding to different methods for water signal suppression are considered separately, outlining some recent developments in the interference water signal reduction which is very crucial for the correct NMR data acquisition in aqueous electrolytes. Certain selected products are described, like carbon monoxide (CO)-associated liquids, formic acid, methanol, and formaldehyde as examples of the NMR precision for the characterization of important compounds. Further, the quantification of C2 products such as ethanol and acetate is discussed in order to illustrate how the technique can be applied in the elucidation of reaction mechanisms and optimization of catalyst performance. This review covers challenges, advanced methodologies, and emerging trends in order to underline the transformative role that NMR plays in advancing CO2 electrochemical reduction toward sustainable chemical synthesis.

    DOI: 10.1016/j.jelechem.2025.119097

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  • Nuclear magnetic resonance spectroscopy: A comprehensive tool for analyzing liquid products in electrochemical CO2 reduction 査読

    ASA Hatab, YH Ahmad, MF Mady, Y Hassan, A. Zkria, A Sinopoli

    Journal of Electroanalytical Chemistry   2025年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi.org/10.1016/j.jelechem.2025.119097

  • Novel Post-Heat Treatment Green Biodegradable PLA@ SiO2 Nanocomposite Membrane for Water Desalination 査読 国際共著 国際誌

    M. M. Sayed, H.M. Mousa, A. H. El-Shazly, A. Zkria, T. Yoshitake, M. ElKady

    Journal of Environmental Chemical Engineering   2024年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: doi.org/10.1016/j.jece.2024.114378

  • Novel post-heat treatment green biodegradable PLA@SiO<inf>2</inf> nanocomposite membrane for water desalination

    Sayed M.M., Mousa H.M., El-Shazly A.H., Zkria A., Yoshitake T., ElKady M.

    Journal of Environmental Chemical Engineering   12 ( 6 )   2024年12月

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    出版者・発行元:Journal of Environmental Chemical Engineering  

    Membrane distillation (MD) has received significant attention because of its energy efficiency and ability to treat industrial wastewater and salty water. However, the synthetic nature of commonly used membranes raises environmental disposal concerns, requiring the development of alternative eco-membranes. To address this issue, a novel, eco-friendly membrane using polylactic acid (PLA) coated with green silica nanoparticles (SiO2 NPs), modified by post-heat treatment, was developed for effective direct contact membrane distillation (DCMD). Herein, two nanofibrous membranes were fabricated via electrospinning/electrospraying: one, PLA, with a 12.5 wt% PLA solution, and another, PLA@SiO2, with 2 % (w/v) SiO2 NPs coating. The PLA@SiO2 membrane demonstrated enhanced hydrophobicity. Various post-heat treatments were applied to optimize membrane properties, such as structure, pore size, hydrophobicity, liquid entry pressure (LEP), thickness, and thermal stability. In addition, the desalination performance of all membranes was evaluated using a DCMD unit for 6 h. Results showed that the heat-pressed then annealed PLA@SiO2 membrane (denoted M44) exhibited notable improvements, including an LEP of 128.7 kPa, a tunable pore size of 0.21 μm, and a contact angle of 135.9°. Furthermore, the M44 membrane demonstrated a porosity of 80.5 %, a stable permeate flux of 14.3 kg.m−2.h−1, and an exceptional salt rejection of 99.99 % over a 24 h DCMD test. This novel eco-membrane shows promising potential for efficient desalination and represents a significant advancement in sustainable MD applications.

    DOI: 10.1016/j.jece.2024.114378

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  • Novel eco-friendly nanodiamonds@chitosan hybrid microcapsules via facile electrospraying for self-healing and anticorrosion coating

    Uko L., Noby H., Zkria A., Elkady M.

    Diamond and Related Materials   148   2024年10月   ISSN:09259635

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    出版者・発行元:Diamond and Related Materials  

    Nanodiamonds were immobilized into chitosan biopolymer to fabricate hybrid microcapsules via electrospraying technique. Previously optimized electrospraying parameters for the formulation of chitosan microcapsules were adjusted to accommodate the immobilized nanodiamonds and maintain a suitable capsule size for the novel hybrid. The yield and entrapment efficiency of the composite microcapsules, including capsule strength were analyzed. The chemical structure, elemental composition, crystalline phases, size distribution, surface morphology, and thermal stability of microcapsules were assessed by Fourier transform infrared (FTIR) spectroscopy, energy dispersive x-ray spectroscopy (EDX), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA), respectively. The results demonstrated a 39 % reduction in the size of composite microcapsules and sphericity improvement after the adjustment. There was a general observation of good yield and immobilization efficiency with the maximum at 96.2 % and 93.8 % for yield and entrapment efficiency, respectively. Characterized composite microcapsules showed desirable morphology, good thermal stability and enhanced mechanical strength, and overall successful fabrication of the hybrid microcapsules. The hybrid microcapsules were subsequently loaded in epoxy resin and coated on a steel substrate to assess their self-healing and anticorrosion abilities. Cross-scratched coating samples were monitored visually for healing efficiency and further analyzed with EIS and potentiodynamic polarization. The self-healing coating showed efficient self-healing and anticorrosion capabilities with a healing efficiency of 97.3 % and a protection efficiency of 99.4 %, confirming the unique feature of the hybrid chitosan-nanodiamonds microparticles for self-healing and anticorrosion purposes.

    DOI: 10.1016/j.diamond.2024.111436

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  • Experimental investigation of copper oxide nanofluids for enhanced oil recovery in the presence of cationic surfactant using a microfluidic model

    Tuok L.P., Elkady M., Zkria A., Yoshitake T., Abdelkader S.A., Seyam D.F., El-Moneim A.A., El-Bab A.M.R.F., Eldemerdash U.N.

    Chemical Engineering Journal   488   2024年5月   ISSN:13858947

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    出版者・発行元:Chemical Engineering Journal  

    Microfluidics is an appealing technique for enhanced oil recovery since it offers numerous advantages over traditional core flooding mechanisms due to their realistic representation of reservoir conditions at the microscale. In this work, we investigated the performance of copper oxide-based nanofluids in the presence of a DCMS-8 cationic surfactant. First, copper oxide nanoparticles of an average particle size of 10 nm were synthesized by the sol–gel method and characterized using various characterization techniques. The results indicated that copper oxide and surfactant-based nanofluids reduced the interfacial tension by 54 %, depending on the concentration of nanoparticles in the suspension. Furthermore, the formation wettability alteration was investigated using contact angle measurements, and the results showed that nanofluid was able to reduce the contact angle from 48o to 20o in 10 min. The shear rheological response indicated that the nanofluids could reduce the viscosity of crude oil from 0.48 (Pa s) to 0.31 (Pa s). Notably, the flooding results showed that copper oxide-based nanofluids were able to recover 61 % of the original oil initially in place, with additional recovery rates of 65 % and 72 % when used with cationic surfactants, polyvinyl alcohol (PVA), and polyvinyl pyrrolidone (PVP), respectively. Finally, the fluorescent images confirmed that surfactant-based nanofluid has a higher sweeping efficiency in porous formation. In this study, the use of copper oxide nanoparticles and cationic surfactant has resulted in the creation of captivating and compelling nanofluids that exhibit reasonable stability of nanoparticles in the base fluid and high recovery rates of residual oil.

    DOI: 10.1016/j.cej.2024.151011

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  • Maximizing visible Raman resolution of nanodiamond grains fabricated by coaxial arc plasma deposition through oxygen plasma etching optimization

    Valappil S.M., Zkria A., Sittimart P., Ohmagari S., Yoshitake T.

    Surface and Interface Analysis   56 ( 4 )   230 - 238   2024年4月   ISSN:01422421

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    出版者・発行元:Surface and Interface Analysis  

    Among the nondestructive carbon material characterization tools, the prominence of visible Raman spectroscopy has surged remarkably for many years due to its ability to explore a diverse array of carbon bonding configurations. However, to fully unlock the distinctive features concealed within carbon composite materials, additional specimen treatments or precise spectroscope calibrations are necessary. In the same regard, the tiny diamond grain size (5–10 nm) and the pronounced amount of sp2 carbon in the ultrananocrystalline diamond film represent major challenges in visible light excitation. In this work, we employ calibrated oxygen plasma reactive ion etching conditions to manifest the nanodiamond visible Raman signature from ultrananocrystalline diamond/amorphous carbon composite (UNCD/a-C) films fabricated by coaxial arc plasma deposition. Upon plasma etching, the broad defect band in the visible Raman spectra converged toward the diamond characteristic Raman peak at 1332 cm−1. A detailed explanation of band components of the Raman spectra is extracted through peak fitting procedures. The results of Raman spectroscopy are further correlated with the electrical characteristics of the nitrogen-doped UNCD/a-C films due to the optimized oxygen plasma etching processes.

    DOI: 10.1002/sia.7289

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  • Engineered eco-friendly composite membranes with superhydrophobic/hydrophilic dual-layer for DCMD system

    Sayed M.M., Noby H., Zkria A., Mousa H.M., Yoshitake T., ElKady M.

    Chemosphere   352   2024年3月   ISSN:00456535

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    出版者・発行元:Chemosphere  

    Considerable advancements have been made in the development of hydrophobic membranes for membrane distillation (MD). Nonetheless, the environmentally responsible disposal of these membranes poses a critical concern due to their synthetic composition. Herein, an eco-friendly dual-layered biopolymer-based membrane was fabricated for water desalination. The membrane was electrospun from two bio-polymeric layers. The top hydrophobic layer comprises polycaprolactone (PCL) and the bottom hydrophilic layer from cellulose acetate (CA). Additionally, silica nanoparticles (SiO2 NPs) were electrosprayed onto the top layer of the dual-layered PCL/CA membrane to enhance the hydrophobicity. The desalination performance of the modified PCL-SiO2/CA membrane was compared with the unmodified PCL/CA membrane using a direct contact membrane distillation (DCMD) unit. Results revealed that silica remarkably improves membrane hydrophobicity. The modified PCL-SiO2/CA membrane demonstrated a significant increase in water contact angle of 152.4° compared to 119° for the unmodified membrane. In addition, PCL-SiO2/CA membrane has a smaller average pore size of 0.23 ± 0.16 μm and an exceptional liquid entry pressure of water (LEPw), which is 3.8 times higher than that of PCL/CA membrane. Moreover, PCL-SiO2/CA membrane achieved a durable permeate flux of 15.6 kg/m2.h, while PCL/CA membrane showed unstable permeate flux decreasing approximately from 25 to 12 kg/m2.h over the DCMD test time. Furthermore, the modified PCL-SiO2/CA membrane achieved a high salt rejection value of 99.97% compared to a low value of 86.2% for the PCL/CA membrane after 24 h continuous DCMD operation. In conclusion, the proposed modified PCL-SiO2/CA dual-layer biopolymeric-based membrane has considerable potential to be used as an environmentally friendly membrane for the MD process.

    DOI: 10.1016/j.chemosphere.2024.141468

    Scopus

  • Engineered eco-friendly composite membranes with superhydrophobic/hydrophilic dual-layer for DCMD system 招待 査読 国際誌

    @Mostafa M Sayed, @H Noby, #Abdelrahman Zkria, @Hamouda M Mousa, #Tsuyoshi Yoshitake, @Marwa ElKady

    Chemosphere   2024年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Herein, an eco-friendly dual-layered biopolymer-based membrane was fabricated for water desalination. The membrane was electrospun from two bio-polymeric layers. The top hydrophobic layer comprises polycaprolactone (PCL) and the bottom hydrophilic layer from cellulose acetate (CA). Additionally, silica nanoparticles (SiO2 NPs) were electrosprayed onto the top layer of the dual-layered PCL/CA membrane to enhance the hydrophobicity. The desalination performance of the modified PCL-SiO2/CA membrane was compared with the unmodified PCL/CA membrane using a direct contact membrane distillation (DCMD) unit. Results revealed that silica remarkably improves membrane hydrophobicity. The modified PCL-SiO2/CA membrane demonstrated a significant increase in water contact angle of 152.4° compared to 119° for the unmodified membrane.

    DOI: https://doi.org/10.1016/j.chemosphere.2024.141468

    その他リンク: https://www.sciencedirect.com/science/article/pii/S0045653524003618

  • Recent Progress in Fabrication of Eco-membranes for Membrane Distillation: A Mini-Review

    Sayed M.M., Mousa H.M., El-Shazly A.H., Zkria A., Yoshitak T., Elkady M.

    International Exchange and Innovation Conference on Engineering and Sciences   10   986 - 991   2024年

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    出版者・発行元:International Exchange and Innovation Conference on Engineering and Sciences  

    Membrane distillation (MD) is an emerging water purification and desalination technology that offers several advantages over conventional thermal and membrane-based processes. As environmental concerns grow, there is a significant interest in developing eco-friendly membranes for MD applications. This mini-review investigates recent progress in the fabrication of eco-membranes for membrane distillation. Key advancements include using natural polymers like chitosan and cellulose, biodegradable synthetic polymers, and inorganic materials to create more sustainable membrane options. Fabrication techniques such as electrospinning and phase inversion have produced highperformance eco-membranes with enhanced permeability, selectivity, and stability. While challenges remain in scaling up production and optimizing long-term performance, the potential of eco-membranes to significantly reduce MD processes' environmental impact is a promising development that cannot be overlooked. This review provides an overview of eco-membrane materials, fabrication methods, performance characteristics, and future research directions to guide further development in this rapidly evolving field.

    DOI: 10.5109/7323379

    Scopus

  • Properties Evaluation of Eco-friendly Chitosan Microcapsules Fabricated with Oxalic Acid and Sodium Phosphate Dibasic Mixed Cross-linker

    Uko L., Noby H., Zkria A., Elkady M.

    AIP Conference Proceedings   3018 ( 1 )   2023年11月   ISSN:0094243X

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    出版者・発行元:AIP Conference Proceedings  

    Crosslinking of chitosan microcapsules is important for control purposes according to their applications and influences their mechanical, thermal, and chemical stability, and tripolyphosphate (TPP) has been predominantly utilized in the electrospray technique for their production. The properties of chitosan microcapsules produced by electrospraying technique and cross-linked with a mixed cross-linking solution (OxPh), consisting of oxalic acid and sodium phosphate dibasic were studied. The formed capsules were characterized by SEM, XRD, FTIR, and the stability and mechanical properties of the capsules were studied. The cross-linked microcapsules provided smooth morphology and exhibited mechanical strength of 80% in the undried state, with dried state mechanical strength of 21.2N as against 19.8N of TPP cross-linked chitosan microcapsules. The microcapsules were also stable in a pH solution of 3.0-5.0.

    DOI: 10.1063/5.0171484

    Scopus

  • Heteroepitaxial growth of β-Ga<inf>2</inf>O<inf>3</inf> thin films on single crystalline diamond (111) substrates by radio frequency magnetron sputtering

    Kusaba T., Sittimart P., Katamune Y., Kageura T., Naragino H., Ohmagari S., Valappil S.M., Nagano S., Zkria A., Yoshitake T.

    Applied Physics Express   16 ( 10 )   2023年10月   ISSN:18820778

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    出版者・発行元:Applied Physics Express  

    In this work, we demonstrate the first achievement in heteroepitaxial growth of β-Ga2O3 thin films on single crystalline diamond (111) wafers using RF magnetron sputtering. A single monoclinic (β-phase) structure with a monofamily { 2 ¯ 01} plane was obtained. XRD pole figure shows ( 2 ̅ 02) and (002) textures of the ( 2 ̅ 01) β-Ga2O3 plane parallel to (111) diamond with six distinct rotational domains, confirming successful epitaxial growth. Collectively, this research provides valuable insights into the epitaxial growth of β-Ga2O3 on diamond via sputtering, paving the way for scalable β-Ga2O3/diamond heterostructures for future electronic and optoelectronic applications with not only high performance but also effective self-thermal management.

    DOI: 10.35848/1882-0786/acfd07

    Scopus

  • Synergistic effects of optimal negative bias-enhanced growth of quenched-produced diamond films on titanium substrates

    Osman L., Zkria A., Ali A.M., Nagano S., Naragino H., Yoshitake T.

    Applied Physics Express   16 ( 7 )   2023年7月   ISSN:18820778

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    出版者・発行元:Applied Physics Express  

    We report on negative bias-enhanced growth of quenched-produced diamond films on titanium using hybrid coaxial arc plasma deposition at room temperature. Optimizing the bias voltage to −40 V resulted in a spontaneous formation of a titanium carbide interfacial layer, which caused a significant increase in the adhesion strength from 16 to 48 N. Selective etching of undesired sp 2-C bonded atoms and ultrafast quenching of the energetic carbon ions (C+) promoted the growth of dense sp 3-C bonded atoms, achieving a superhardness of 96 GPa, comparable to natural diamond. These pioneering findings have the potential to revolutionize multifunctional materials for biomedical applications.

    DOI: 10.35848/1882-0786/acdfb7

    Scopus

  • Hybrid concentrator photovoltaic/membrane distillation system for potable water production using new fabricated PS/ZIF_L membrane 招待 査読 国際誌

    Mohammed Rabie, Asmaa Elrasheedy, Abdelrahman Zkria, MF Elkady, Tsuyoshi Yoshitake, AH El-Shazly

    Journal of Water Process Engineering   2023年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    A hybrid system is proposed to use solar energy as a heating source for the membrane distillation unit. Concentrating photovoltaic needs an efficient cooling system to manage the excess thermal load. Two microchannel heat sinks were proposed to keep the cells from thermal degradation and simultaneously transfer the excess thermal energy to the membrane distillation unit. The results showed a maximum coolant outlet temperature of 59 °C, which is adequate for the membrane distillation unit. A new composite electrospun nanofibrous membrane was successfully synthesized to reduce unfavorable membrane wettability. First, ZIF-L nanoparticles were synthesized and characterized to prove successful preparation, then used as a nanofiller with polystyrene as the polymer membrane matrix for the first time.

    DOI: https://doi.org/10.1016/j.jwpe.2023.103872

    その他リンク: https://www.sciencedirect.com/science/article/pii/S2214714423003914

  • Hybrid concentrator photovoltaic/membrane distillation system for potable water production using new fabricated PS/ZIF_L membrane

    Rabie M., Elrasheedy A., Zkria A., Elkady M.F., Yoshitake T., El-Shazly A.H.

    Journal of Water Process Engineering   53   2023年7月   ISSN:22147144

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    出版者・発行元:Journal of Water Process Engineering  

    A hybrid system is proposed to use solar energy as a heating source for the membrane distillation unit. Concentrating photovoltaic needs an efficient cooling system to manage the excess thermal load. Two microchannel heat sinks were proposed to keep the cells from thermal degradation and simultaneously transfer the excess thermal energy to the membrane distillation unit. The results showed a maximum coolant outlet temperature of 59 °C, which is adequate for the membrane distillation unit. A new composite electrospun nanofibrous membrane was successfully synthesized to reduce unfavorable membrane wettability. First, ZIF-L nanoparticles were synthesized and characterized to prove successful preparation, then used as a nanofiller with polystyrene as the polymer membrane matrix for the first time. SEM, XRD, FTIR, static water contact angle, membrane thickness, and porosity were introduced to prove nanofillers' successful preparation and encapsulation. The antiwetting phenomenon was proven by the measured contact angle of 160°. Furthermore, the fabricated membrane was tested experimentally on a lap scale direct contact membrane distillation unit with a productivity of about 4 kg/m2 h and 18 ppm water quality at 55 °C hot water temperature. Also, the introduced membrane outperformed the productivity of the commercial PVDF membrane at all examined operating conditions.

    DOI: 10.1016/j.jwpe.2023.103872

    Scopus

  • Influence of different pretreatments on the adhesion of nanodiamond composite films on Ti substrates via coaxial arc plasma deposition

    Osman L., Ali A.M., Zkria A., Naragino H., Yoshitake T.

    Materials Research Express   10 ( 6 )   2023年6月

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    出版者・発行元:Materials Research Express  

    In this study, we report on the novel growth of nanodiamond composite (NDC) films on titanium (Ti) substrates using the coaxial arc plasma deposition (CAPD) at room temperature, which offers several advantages over conventional growth techniques. CAPD employs a unique coaxial arc plasma gun structure that provides a supersaturated condition of highly energetic carbon ions (C+) for ultrafast quenching on the substrate, promoting the growth of nanodiamond grains. This allows for NDC films’ growth on diverse substrates without the need for initial seeding or substrate heating. However, the growth of NDC films on Ti substrates at room temperature is challenging due to the native oxide layer (TiO2). Here, we grew NDC films on Ti substrates using three different pretreatments: (i) hydrofluoric acid (HF) etching, (ii) insertion of a titanium carbide (TiC) intermediate layer, and (iii) in situ Ar+ plasma etching. The morphology and structure of the grown NDC films were examined by 3D laser, high-resolution scanning electron microscopies (HR-SEM), Raman, and x-ray photoelectron (XPS) spectroscopies. Our results demonstrate that in situ Ar+ plasma etching is the most effective pretreatment method for completely removing the native TiO2 layer compared to the other two ex situ pretreatments, in which re-oxidation is more likely to occur after these pretreatments. Furthermore, NDC films grown using the hybrid Ar+ ion etching gun (IG) and CAPD exhibit the highest sp 3 content (63%) and adhesion strength (16 N).

    DOI: 10.1088/2053-1591/acd992

    Scopus

  • Corrosion‐Resistive and Low Specific Contact Resistance Ohmic Contacts to Semiconducting Diamonds Using Nanocarbon Electrodes 招待 査読 国際誌

    Sreenath Mylo Valappil, Abdelrahman Zkria, Shinya Ohmagari, Hiroshi Naragino, Hiromitsu Kato, Tsuyoshi Yoshitake

    Physica Status Solidi A   220 ( 3 )   2200627   2023年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    The realization of diamond‐based advanced devices is interrelated with the fabrication of practical ohmic contacts. Contrary to boron‐doped, the phosphorus‐doped diamonds with interface carbide forming Ti‐based conventional ohmic contacts find their limitation in device fabrication due to the high contact resistance. Herein, nanocarbon ohmic contacts are deposited by a coaxial arc plasma gun on semiconducting diamonds, and their composite structure which facilitates exceptional contact properties is explored. A comparative electrical characterization between nanocarbon ohmic contacts and conventional Ti‐based contacts is performed on a heavily phosphorus‐doped diamond, and they exhibited one‐order declination in specific contact resistance.

  • Corrosion-Resistive and Low Specific Contact Resistance Ohmic Contacts to Semiconducting Diamonds Using Nanocarbon Electrodes

    Mylo Valappil S., Zkria A., Ohmagari S., Naragino H., Kato H., Yoshitake T.

    Physica Status Solidi (A) Applications and Materials Science   220 ( 3 )   2023年2月   ISSN:18626300

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    出版者・発行元:Physica Status Solidi (A) Applications and Materials Science  

    The realization of diamond-based advanced devices is interrelated with the fabrication of practical ohmic contacts. Contrary to boron-doped, the phosphorus-doped diamonds with interface carbide forming Ti-based conventional ohmic contacts find their limitation in device fabrication due to the high contact resistance. Herein, nanocarbon ohmic contacts are deposited by a coaxial arc plasma gun on semiconducting diamonds, and their composite structure which facilitates exceptional contact properties is explored. A comparative electrical characterization between nanocarbon ohmic contacts and conventional Ti-based contacts is performed on a heavily phosphorus-doped diamond, and they exhibited one-order declination in specific contact resistance. In addition to the low contact resistance, an ideal ohmic electrode is preferable to have good mechanical adhesion and corrosion resistance for device applications. The contact behavior of n-type diamond/nanocarbon against an extremely corrosive environment realized by boiling H2SO4 + HNO3 solution is analyzed. The nanocarbon ohmic contacts exhibit excellent corrosion resistance and mechanical adhesion over conventional Ti-based contacts. A similar trend is also observed for nanocarbon contacts on boron-doped diamonds. The modest effect on the transfer length of the nanocarbon contacts with respect to acid treatment sessions indicates a tightly bonded diamond/nanocarbon interface and actively suggests their application in highly-corrosive and harsh environments.

    DOI: 10.1002/pssa.202200627

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  • Advances in Nitrogen-Vacancy color centers in diamond for magnetometry: Advantages and Challenges

    Abdelrahman A., Zkria A., Yoshitake T.

    International Exchange and Innovation Conference on Engineering and Sciences   9   417 - 422   2023年

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    出版者・発行元:International Exchange and Innovation Conference on Engineering and Sciences  

    Color centers in diamonds have promising and unique properties that can be optimized and engineered for several quantum-sensing applications. The negatively charged Nitrogen-vacancy (NV) center is one of the outstanding candidates due to its stable luminescence and spin features. It has a long coherence time that can be initialized and manipulated with high accuracy at room temperature. Nonetheless, many parameters, namely; nonradiative centers, complex defects, and nitrogen-based defect centers can severely affect the desirable properties of these NV centers. In this review, we highlight the recent advances of color center fabrication, parameters optimization, and current challenges to enhance these properties, with main focus on magnetometry applications.

    DOI: 10.5109/7158033

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  • Synthesis of Quenched-produced Diamond by physical vapor deposition for various applications

    Zkria A.

    International Exchange and Innovation Conference on Engineering and Sciences   9   XVIII - XIX   2023年

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    出版者・発行元:International Exchange and Innovation Conference on Engineering and Sciences  

    Nanodiamond composite coatings combine diamond crystallites embedded inside an amorphous carbon phase. Owing to sp3 hybridized carbon bonding of diamond crystallites, these films yield impressive mechanical properties, outstanding biocompatibility, and antibacterial properties. Commonly, Nanodiamond films are prepared by chemical vapor deposition (CVD). In CVD, the initial nucleation of diamond is required, specifically, a seeding procedure with diamond powders as a pretreatment of substrates prior to the film deposition, and high substrate temperature. Such preparation conditions limit the variety of non-diamond substrates used for the heterogeneous growth of diamond films by CVD. On the other hand, Quenched-produced diamonds, formerly called Nanodiamond (ND) films have been grown by a physical vapor deposition approach, namely coaxial arc plasma deposition (CAPD), without the pretreatment of substrates and at room temperature. In our research group at Kyushu University, we realized the growth of Quenched-produced diamond films by the CAPD method. For electronic applications, we demonstrated the n-and p-type semiconductors by Nitrogen and Boron doping, respectively [1-3]. Most recently, we succeeded in the growth of Q-diamond on Titanium substrates at room temperature by a hybrid configuration of ion etching gun (IG) and CAPD employing in-situ Argon etching. The grown Q-diamond on Ti has been proposed for the implant applications [4,5]

    DOI: 10.5109/7157924

    Scopus

  • Electrospraying of Bio-Based Chitosan Microcapsules Using Novel Mixed Cross-Linker: Experimental and Response Surface Methodology Optimization

    Uko L., Noby H., Zkria A., ElKady M.

    Materials   15 ( 23 )   2022年12月

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    出版者・発行元:Materials  

    Chitosan microcapsules draw attention due to their biodegradability, biocompatibility, antibacterial behavior, low cost, easy processing, and the capability to be used for different applications. This study utilized the electrospraying technique for the chitosan microcapsules formulation. As a novel cross-linking agent, a mixture of oxalic acid and sodium phosphate dibasic was utilized as a collecting solution for the first time in the electrospraying of chitosan microcapsules. Scanning Electron Microscopy (SEM) was utilized to optimize the spherical morphology and size of the experimentally obtained microcapsules. The different parameters, including chitosan concentration, applied voltage, flow rate, and tip-to-collector (TTC) distance, affecting the microcapsules’ size, sphericity, yield, and combined effects were optimized using Surface Responses Methodology (RSM). The Analysis of Variance (ANOVA) was utilized to obtain the impact of each parameter on the process responses. Accordingly, the results illustrated the significant impact of the voltage parameter, with the highest F-values and least p-values, on the capsule size, sphericity, and yield. The predicted optimum conditions were determined as 5 wt% chitosan concentration, 7 mL/h flow rate, 22 kV, and 8 cm TTC distance. The predicted responses at the optimized conditions are 389 µm, 0.72, and 80.6% for the capsule size, sphericity, and yield, respectively. While the validation of the model prediction was conducted experimentally, the obtained results were 369.2 ± 23.5 µm, 0.75 ± 0.04, and 87.3 ± 11.4%, respectively. The optimization process was successfully examined for the chitosan microcapsules manufacturing.

    DOI: 10.3390/ma15238447

    Scopus

  • Overcoming the impact of post-annealing on uniformity of diamond (100) Schottky barrier diodes through corrosion-resistant nanocarbon ohmic contacts

    Mylo Valappil S., Zkria A., Ohmagari S., Yoshitake T.

    Materials Research Express   9 ( 11 )   2022年11月

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    出版者・発行元:Materials Research Express  

    Diamond-based Schottky barrier diodes (SBDs) are involved in many technological applications. In a conventional SBD fabrication process that involves interface carbide forming ohmic contacts, a post-annealing step is necessary for ohmic contacts to achieve their operational efficiency. However, this step deteriorates the essential oxygen coverage at the diamond surface which in turn affects SBDs uniformity. So, an additional oxygen termination step is necessary prior to Schottky metal deposition. In this study, a non-conventional fabrication method is introduced using corrosion-resistant nanocarbon ohmic contacts fabricated by coaxial arc plasma deposition. As a result, The SBD parameters including ideality factors and barrier heights exhibited high uniformity with a very small standard deviation for the proposed fabrication process flow when compared with process flow including a post-annealing step. Furthermore, the contact behavior of nanocarbon ohmic electrodes is investigated on a heavily boron-doped diamond film using circular transmission line model theory and a specific contact resistance of ∼10−5 Ωcm2 is obtained, suggesting the practical application of nanocarbon ohmic contacts for diamond-based electronic devices.

    DOI: 10.1088/2053-1591/aca31f

    Scopus

  • Adhesion of nanodiamond composite films on Ti substrates at room temperature via hybrid ion etching gun and coaxial arc plasma deposition

    Osman L., Ali A.M., Zkria A., Naragino H., Yoshitake T.

    Applied Physics Express   15 ( 11 )   2022年11月   ISSN:18820778

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    出版者・発行元:Applied Physics Express  

    It has been extremely difficult for nanodiamond composite (NDC) films to be deposited on Ti due to a large thermal expansion coefficient difference. The native oxide layer on Ti is another problem preventing the appropriate adhesion of NDC films and subsequent delamination. In this work, innovative room temperature adhesion of 3 μm NDC films with 54 GPa hardness on Ti substrates was accomplished via a hybrid system of ion etching gun and coaxial arc plasma deposition (CAPD). Ar+ plasma etching is capable to terminate the superficial TiO2 layer and manipulates substrate morphology during CAPD provides instantaneous deposition of NDC films at room temperature.

    DOI: 10.35848/1882-0786/ac99b6

    Scopus

  • Nanocarbon ohmic electrodes fabricated by coaxial arc plasma deposition for phosphorus-doped diamond electronics application

    Valappil S.M., Ohmagari S., Zkria A., Sittimart P., Abubakr E., Kato H., Yoshitake T.

    AIP Advances   12 ( 8 )   2022年8月

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    出版者・発行元:AIP Advances  

    n-Type (phosphorus-doped) diamond is a promising material for diamond-based electronic devices. However, realizing good ohmic contacts for phosphorus-doped diamonds limits their applications. Thus, the search for non-conventional ohmic contacts has become a hot topic for many researchers. In this work, nanocarbon ohmic electrodes with enhanced carrier collection efficiency were deposited by coaxial arc plasma deposition. The fabricated nanocarbon ohmic electrodes were extensively examined in terms of specific contact resistance and corrosion resistance. The circular transmission line model theory was used to estimate the charge collection efficiency of the nanocarbon ohmic electrodes in terms of specific contact resistance at a specific voltage range (5-10 V); they exhibited a specific contact resistance of 1 × 10-3 ωcm2. The result revealed one order reduction in the specific contact resistance and, consequently, a potential drop at the diamond/electrode interface compared to the conventional Ti electrodes. Moreover, the fabricated nanocarbon electrodes exhibited high mechanical adhesion and chemical inertness over repeated acid treatments. In device applications, the nanocarbon electrodes were evaluated for Ni/n-type diamond Schottky diodes, and they exhibited nearly one order enhancement in the rectification ratio and a fast charge collection at lower biasing voltages.

    DOI: 10.1063/5.0093470

    Scopus

  • Nanocarbon ohmic electrodes fabricated by coaxial arc plasma deposition for phosphorus-doped diamond electronics application 招待 査読 国際誌

    Sreenath Mylo Valappil, Shinya Ohmagari, Abdelrahman Zkria, Phongsaphak Sittimart, Eslam Abubakr, Hiromitsu Kato, Tsuyoshi Yoshitake

    AIP Advances   2022年8月

     詳細を見る

    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    n-Type (phosphorus-doped) diamond is a promising material for diamond-based electronic devices. However, realizing good ohmic contacts for phosphorus-doped diamonds limits their applications. Thus, the search for non-conventional ohmic contacts has become a hot topic for many researchers. In this work, nanocarbon ohmic electrodes with enhanced carrier collection efficiency were deposited by coaxial arc plasma deposition. The fabricated nanocarbon ohmic electrodes were extensively examined in terms of specific contact resistance and corrosion resistance. The circular transmission line model theory was used to estimate the charge collection efficiency of the nanocarbon ohmic electrodes in terms of specific contact resistance at a specific voltage range (5–10 V); they exhibited a specific contact resistance of 1× 10− 3 Ωcm 2.

    DOI: https://doi.org/10.1063/5.0093470

  • Nano-bio effects: Interaction of ZnO and DNA-bases 招待 査読 国際誌

    Bithi Paul, Abdullah Mamun, Ariful Haque, Monika Paul, Abdelrahman Zkria, Kartik Ghosh

    Nano-Structures & Nano-Objects   2022年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    In this study, we report on the complex formation and characterization of nano-bio conjugates synthesized by the sol–gel chemical method. The nano-bio conjugates, consisting of inorganic ZnO nanoparticles (NPs) and organic nitrogenous bases of DNA (Thymine and Cytosine), are investigated using electron microscopies, molecular vibrational analysis and X-ray spectroscopies. In this experimental investigation, we used two basic nitrogenous bases of DNA – Cytosine, and Thymine. The X-ray diffraction patterns of both ZnO NP and the nanoconjugate (NJ) reveal a highly phase pure ZnO structure with negligible changes in the unit cell dimensions. The Raman peaks due to the molecular vibration of C2=O7 and C4=O8 sites of Thymine and C=O and N-H sites in Cytosine are shifted due to the cation affinity after the interaction with ZnO NPs.

    その他リンク: https://www.sciencedirect.com/science/article/pii/S2352507X2200035X

  • Nano-bio effects: Interaction of ZnO and DNA-bases

    Paul B., Mamun A., Haque A., Paul M., Zkria A., Ghosh K.

    Nano-Structures and Nano-Objects   31   2022年7月

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    出版者・発行元:Nano-Structures and Nano-Objects  

    In this study, we report on the complex formation and characterization of nano-bio conjugates synthesized by the sol–gel chemical method. The nano-bio conjugates, consisting of inorganic ZnO nanoparticles (NPs) and organic nitrogenous bases of DNA (Thymine and Cytosine), are investigated using electron microscopies, molecular vibrational analysis and X-ray spectroscopies. In this experimental investigation, we used two basic nitrogenous bases of DNA – Cytosine, and Thymine. The X-ray diffraction patterns of both ZnO NP and the nanoconjugate (NJ) reveal a highly phase pure ZnO structure with negligible changes in the unit cell dimensions. The Raman peaks due to the molecular vibration of C2=O7 and C4=O8 sites of Thymine and C=O and N-H sites in Cytosine are shifted due to the cation affinity after the interaction with ZnO NPs. The shifted XPS spectra towards higher binding energies of the NJ divulge the atomic level interaction between the DNA bases and ZnO NPs at the surface. Moreover, the formation of NJs reduces the surface defect states of the ZnO NPs and increases the fluorescence properties by quenching the oxygen vacancy concentration. Thus, the current study on the interfacial properties of organic–inorganic conjugate materials opens new frontiers for developing novel nano-bio conjugate materials and their integration for targeted drug delivery, biomolecular sensing and therapeutic tools medicine applications.

    DOI: 10.1016/j.nanoso.2022.100898

    Scopus

  • Laser-Assisted Growth of Carbon-Based Materials by Chemical Vapor Deposition

    Odusanya A., Rahaman I., Sarkar P.K., Zkria A., Ghosh K., Haque A.

    C-Journal of Carbon Research   8 ( 2 )   2022年6月

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    出版者・発行元:C-Journal of Carbon Research  

    Carbon-based materials (CBMs) such as graphene, carbon nanotubes (CNT), highly ordered pyrolytic graphite (HOPG), and pyrolytic carbon (PyC) have received a great deal of attention in recent years due to their unique electronic, optical, thermal, and mechanical properties. CBMs have been grown using a variety of processes, including mechanical exfoliation, pulsed laser deposition (PLD), and chemical vapor deposition (CVD). Mechanical exfoliation creates materials that are irregularly formed and tiny in size. On the other hand, the practicality of the PLD approach for large-area high-quality CMB deposition is quite difficult. Thus, CVD is considered as the most effective method for growing CBMs. In this paper, a novel pulsed laser-assisted chemical vapor deposition (LCVD) technique was explored to determine ways to reduce the energy requirements to produce high quality CBMs. Different growth parameters, such as gas flow rate, temperature, laser energy, and deposition time were considered and studied thoroughly to analyze the growth pattern. CBMs are grown on Si and Cu substrates, where we find better quality CBM films on Cu as it aids the surface solubility of carbon. Raman spectroscopy confirms the presence of high-quality PyC which is grown at a temperature of 750 °C, CH4 gas flow rate of 20 sccm, a laser frequency of 10 Hz, and an energy density of 0.116 J/cm2 per pulse. It is found that the local pulsed-laser bombardment helps in breaking the carbon-hydrogen bonds of CH4 at a much lower substrate temperature than its thermal decomposition temperature. There is no significant change in the 2D peak intensity in the Raman spectrum with the further increase in temperature which is the indicator of the number of the graphene layer. The intertwined graphene flakes of the PyC are observed due to the surface roughness, which is responsible for the quenching in the Raman 2D signal. These results will provide the platform to fabricate a large area single layer of graphene, including the other 2D materials, on different substrates using the LCVD technique.

    DOI: 10.3390/c8020024

    Scopus

  • Pronounced effect of PbI<inf>2</inf> nanoparticles doping on optoelectronic properties of PVA films for photo-electronic applications

    El-Zahhar A.A., Ashraf I.M., Idris A.M., Zkria A.

    Physica B: Condensed Matter   630   2022年4月   ISSN:09214526

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    出版者・発行元:Physica B: Condensed Matter  

    Composite films of polyvinyl alcohol/lead iodide (PVA/PbI2) were prepared with different concentrations of PbI2 using low-cost casting process. The characteristics of the prepared films were analyzed by XRD and SEM. The XRD results showed increased crystalline nature with PbI2 content and the SEM micrographs revealed homogeneous particles distribution of PbI2 within the polymer. The optical parameters of PVA/PbI2 films were measured through UV–Vis absorption-transmittance spectroscopy. The indirect energy gap for PVA was found to be 4.75 eV, while the PVA/PbI2 film with 10 wt% PbI2 showed direct transition of 2.47 eV and indirect transition of 2.15 eV. The PVA film resistivity was found to be 1.79 × 109 Ω cm in the dark and decreased to1.85 × 108 Ω cm at 7000 lux. The film resistivity was found to decrease as the PbI2 content ratio increased up to 10 wt%. The results also showed gradual increase in photo sensitivity with increasing PbI2 content ratio in the composite films. The optical properties revealed that the composite films (PVA/PbI2) could be used in different optoelectronic applications.

    DOI: 10.1016/j.physb.2021.413604

    Scopus

  • Pronounced effect of PbI2 nanoparticles doping on optoelectronic properties of PVA films for photo-electronic applications 招待 査読 国際誌

    Adel A El-Zahhar, IM Ashraf, Abubakr M Idris, Abdelrahman Zkria

    Physica B: Condensed Matter   2022年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1016/j.physb.2021.413604

  • Laser-induced novel ohmic contact formation for effective charge collection in diamond detectors

    Abubakr E., Ohmagari S., Zkria A., Ikenoue H., Yoshitake T.

    Materials Science in Semiconductor Processing   139   2022年3月   ISSN:13698001

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    出版者・発行元:Materials Science in Semiconductor Processing  

    In this study, we employed an authentic process for the device fabrication of diamond detectors, wherein thin, highly conductive surface layers were processed in bulk diamond substrate using a nanosecond-pulsed excimer laser with liquid-immersion irradiation. The incorporation of high-concentration phosphorus dopants at 40 nm under the irradiated surface characterized the irradiated areas with much lower electrical resistivity, which was adequate for demonstrating ohmic contacts even with the tungsten probe heads at room temperature. In particular, a low activation energy (<54 meV) of irradiated surfaces enabled space-charge-free build-up effects between the diamond film and external connection. Moreover, the electrical characterization revealed an improved carrier-collection efficiency that was more than three orders of magnitude greater than that of typical Ti/Au diamond ohmic contacts, including a high-response speed of the current pulse to irradiation burst. The laser treatment of diamond films displayed promising results for the fabrication of diamond detectors with minimum power consumption, fastest process rate, and highest visible-light detection that could maintain smooth and stable charge transport. The process allowed selective, patterned doping of the diamond surface, which could be electrically contacted more readily. Furthermore, they could be operated at high temperatures and in radiation-harsh environments with sustainable efficiency.

    DOI: 10.1016/j.mssp.2021.106370

    Scopus

  • Correlated Electrical Conductivities to Chemical Configurations of Nitrogenated Nanocrystalline Diamond Films 招待 査読 国際誌

    Abdelrahman Zkria, Hiroki Gima, Eslam Abubakr, Ashraf Mahmoud, Ariful Haque, and Tsuyoshi Yoshitake

    Nanomaterials   ( 854 )   2022年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.3390/nano12050854

  • Correlated Electrical Conductivities to Chemical Configurations of Nitrogenated Nanocrystalline Diamond Films

    Zkria A., Gima H., Abubakr E., Mahmoud A., Haque A., Yoshitake T.

    Nanomaterials   12 ( 5 )   2022年3月

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    出版者・発行元:Nanomaterials  

    Diamond is one of the fascinating films appropriate for optoelectronic applications due to its wide bandgap (5.45 eV), high thermal conductivity (3320 W m−1·K−1 ), and strong chemical stability. In this report, we synthesized a type of diamond film called nanocrystalline diamond (NCD) by employing a physical vapor deposition method. The synthesis process was performed in different ratios of nitrogen and hydrogen mixed gas atmospheres to form nitrogen-doped (n-type) NCD films. A high-resolution scanning electron microscope confirmed the nature of the deposited films to contain diamond nanograins embedded into the amorphous carbon matrix. Sensitive spectroscopic investigations, including X-ray photoemission (XPS) and near-edge X-ray absorption fine structure (NEXAFS), were performed using a synchrotron beam. XPS spectra indicated that the nitrogen content in the film increased with the inflow ratio of nitrogen and hydrogen gas (IN/H ). NEXAFS spectra revealed that the σ*C–C peak weakened, accompanied by a π*C=N peak strengthened with nitrogen doping. This structural modification after nitrogen doping was found to generate unpaired electrons with the formation of C–N and C=N bonding in grain boundaries (GBs). The measured electrical conductivity increased with nitrogen content, which confirms the suggestion of structural investigations that nitrogen-doping generated free electrons at the GBs of the NCD films.

    DOI: 10.3390/nano12050854

    Scopus

  • Monothetic analysis and response surface methodology optimization of calcium alginate microcapsules characteristics 招待 査読 国際誌

    Joshua Anani, Hussien Noby, Abdelrahman Zkria, Tsuyoshi Yoshitake, Marwa ElKady

    Polymers   2022年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.3390/polym14040709

  • Monothetic Analysis and Response Surface Methodology Optimization of Calcium Alginate Microcapsules Characteristics

    Anani J., Noby H., Zkria A., Yoshitake T., Elkady M.

    Polymers   14 ( 4 )   2022年2月

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    出版者・発行元:Polymers  

    Owing to bio-polymer’s low-cost, environmental friendliness and mechanically stable nature, calcium alginate microcapsules have attracted much interest for their applications in numerous fields. Among the common production methods, the Electrospraying technique has shown a great potential due to smaller shape capsule production and ease of control of independent affecting parameters. Although one factor at a time (OFAT) can predict the trends of parameter effect on size and sphericity, it is inefficient in explaining the complex parameter interaction of the electrospray process. In the current study, the effects of the main parameters affecting on size and sphericity of the microcapsules using OFAT were optimized to attain calcium alginate microcapsules with an average diameter below 100 µm. Furthermore, we propose a statistical model employing the Surface Responses Methodology (RSM) and Central Composite Design (CDD) to generate a quadratic order linear regression model for the microcapsule diameter and sphericity coefficient. Experimentally, microcapsules with a size of 92.586 µm and sphericity coefficient of 0.771 were predicted and obtained from an alginate concentration of 2.013 w/v, with a flowrate of 0.560 mL/h, a needle size of 27 G and a 2.024 w/v calcium chloride concentration as optimum parameters. The optimization processes were successfully aligned towards formation of the spherical microcapsules with smaller average diameter of less than 100 µm, owing to the applied high voltage that reached up to 21 kV.

    DOI: 10.3390/polym14040709

    Scopus

  • Formation of p-n<sup>+</sup> diamond homojunctions by shallow doping of phosphorus through liquid emersion excimer laser irradiation

    Abubakr E., Ohmagari S., Zkria A., Ikenoue H., Pernot J., Yoshitake T.

    Materials Research Letters   10 ( 10 )   666 - 674   2022年

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    出版者・発行元:Materials Research Letters  

    We report the fabrication of p-n + diamond homojunction through an innovative approach of laser irradiation in liquid-ambient. A shallow phosphorus-doped layer with a high electric conductivity is processed on top of a p-type diamond substrate to form the p-n + homojunction. The current–voltage measurements at room temperature confirmed high conductivity of the induced n+ layer and showed exceptional rectification properties with an ideality factor of 1.07, excellent low on-resistance of 3.7 × 10−2 Ωcm2, and current density over 260 Acm−2 at forward-biasing of 10 V. Furthermore, undetectable leakage-current provides a rectification ratio exceeding 1010 at ±6 V, promoting the junction in UV detection applications.

    DOI: 10.1080/21663831.2022.2083457

    Scopus

  • Temperature-dependent impedance spectra of nitrogen-doped ultrananocrystalline diamond films grown on Si substrates 招待 査読 国際誌

    Mahmoud Shaban, Abdelrahman Zkria, Tsuyoshi Yoshitake

    IEEE Access   2020年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: DOI: 10.1109/ACCESS.2020.3046969

  • Diode parameters and ultraviolet light detection characteristics of n-type silicon/p-type nanocrystalline diamond heterojunctions at different temperatures 招待 査読 国際誌

    Rawiwan Chaleawpong, Nathaporn Promros, Abdelrahman Zkria, Peerasil Charoenyuenyao, Eslam Abubakr, Tsuyoshi Yoshitake

    Thin Solid Films   2020年9月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1016/j.tsf.2020.138222

  • Analysis of electrical characteristics of Pd/n-nanocarbon/p-Si heterojunction diodes: By CVf and G/wVf 招待 査読 国際誌

    Abdelrahman Zkria, Eslam Abubakr, Phongsaphak Sittimart, Tsuyoshi Yoshitake

    Journal of Nanomaterials   2020年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

  • Characterization and design optimization of heterojunction photodiodes comprising n-type ultrananocrystalline diamond/hydrogenated amorphous carbon composite and p-type Si 招待 査読 国際誌

    Mahmoud Shaban, Abdelrahman Zkria, Tsuyoshi Yoshitake

    Materials Science in Semiconductor Processing   2018年11月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: https://doi.org/10.1016/j.mssp.2018.06.028

  • Chemical bonding structural analysis of nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite films prepared by coaxial arc plasma deposition 招待 査読 国際誌

    #Hiroki Gima, #Abdelrahman Zkria, @Yuki Katamune, @Ryota Ohtani, @Satoshi Koizumi, @Tsuyoshi Yoshitake

    Applied Physics Express   10 ( 1 )   2017年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Nitrogen-doped ultra-nanocrystalline diamond/hydrogenated amorphous carbon composite films prepared in hydrogen and nitrogen mixed-gas atmospheres by coaxial arc plasma deposition with graphite targets were studied electrically and chemical-bonding-structurally. The electrical conductivity was increased by nitrogen doping, accompanied by the production of n-type conduction. From X-ray photoemission, near-edge X-ray absorption fine-structure, hydrogen forward-scattering, and Fourier transform infrared spectral results, it is expected that hydrogen atoms that terminate diamond grain boundaries will be partially replaced by nitrogen atoms and, consequently, π C–N and C= N bonds that easily generate free electrons will be formed at grain boundaries.

    DOI: 10.7567/APEX.10.015801

  • Current transport mechanisms in n-type ultrananocrystalline diamond/p-type Si heterojunctions 招待 査読 国際誌

    #Abdelrahman Zkria, @Mahmoud Shaban, #Takanori Hanada, @Nathaporn Promros, @Tsuyoshi Yoshitake

    Journal of Nanoscience and Nanotechnology   16 ( 12 )   12749 - 12753   2016年12月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    Nitrogen-doped ultrananocrystalline diamond/hydrogenated amorphous carbon composite (UNCD/a-C:H) films were deposited on P-type Si substrates by coaxial arc plasma deposition. The deposited films possessed N-type conduction, and evidently formed pn heterojunctions with P-type Si substrates. The heterojunction devices showed typical rectification properties similar to those observed for conventional abrupt pn heterojunctions. The conduction mechanisms that govern current transport in these devices were analyzed using dark current–voltage measurements in the temperature range from 300 K to 80 K. The results revealed that a trap-assisted multi-step tunneling process is a dominant mechanism at lower temperatures and low forward bias. At least two defect levels with activation energies of 42 and 24 meV appear to activate this process. At moderate forward bias, the current followed a power-law …

    DOI: 10.1166/jnn.2016.13663

  • Effects of nitrogen doping on the electrical conductivity and optical absorption of ultrananocrystalline diamond/hydrogenated amorphous carbon films prepared by coaxial arc plasma deposition 招待 査読 国際誌

    Abdelrahman Zkria, Yūki Katamune, Tsuyoshi Yoshitake

    Japanese journal of applied physics   2016年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)  

    DOI: DOI 10.7567/JJAP.55.07LE01

    その他リンク: https://iopscience.iop.org/article/10.7567/JJAP.55.07LE01/meta

▼全件表示

書籍等出版物

  • Nanodiamond/Conducting Polymer Nanocomposites for Supercapacitor Applications

    Abdelrahman Zkria, Ali M Ali, Imtenan Mahmoud, Abdalla Abdelwahab, Waleed MA El Rouby, Tsuyoshi Yoshitake

    2022年3月 

     詳細を見る

    記述言語:英語  

    Supercapacitors, known as electrochemical capacitors, are very attractive as energy storage devices due to their high-power density (up to 410 kW kg−1), their unique ability to undergo charge/discharge quickly and their long cycling life (that could reach 4105 cycles). Efforts have been dedicated to develop various carbon-based nanomaterials for energy storage, specially supercapacitors. Carbon-based materials and conducting polymers (ie; Polypyrrole and Polyaniline) are considered the most promising candidates for capacitive materials, as they offer high charging capacity through diverse mechanisms. Among these carbon-based materials are nano-crystalline diamond (NCD) films, which were widely studied during the past decades due to their special features like; short-range sp3 bonded carbon atoms and large surface to volume ratio. Artificial fabrication of NCD films was developed using various techniques like; high-pressure high-temperature (HPHT), chemical vapor deposition, plasma-discharge-stimulated, laser ablation,hot-filament technique,, and coaxial arc plasma deposition. Although carbon-based nanomaterials display good stability in energy storage applications, the capacitance values are yet limited by the microstructures within the materials; Therefore, their nanocomposites with conducting polymers provide higher performance and improved properties. This chapter aims to summarize and discuss the recent synthetic developments of nanocrystalline diamond/conducting polymer nanocomposites, and their applications to energy storage and supercapacitor.

  • Optimization of the Electrospraying Parameters for Formulation of Biopolymeric Microcapsules

    Anani J., Noby H., Zkria A., Yoshitake T., Elkady M.

    Materials Science Forum  2022年    ISSN:02555476

     詳細を見る

    There has been a surge in applying alginate microcapsules in diverse fields due to the numerous advantages of their non-toxicity, simple synthesis, and mechanical and chemical stability. Electrospraying is a simple and excellent technique for producing small microcapsules. This study aimed to analyze the trends in the operational parameters of the electrospraying technique, observed extreme conditions of the electrospraying, and selected the best performing parameters for producing small and spherical microcapsules. Alginate concentration was found to produce smaller microcapsules when kept at a minimum. However, the Implosion of microcapsules formed with less than 2%w/v alginate concentration was observed. Voltage increment produced smaller capsules, and fibre formation began at 21kV. Lower feed rates favoured both smaller microcapsules and better sphericity. Reduction in the needle orifice also favoured the formation of smaller microcapsules with less sphericity. Overall, a needle gauge of 27G, a voltage of 21kV, a flowrate of 0.5ml/h, and 2% w/v calcium chloride concentration were the best parameter combinations for producing small and spherical microcapsules.

    DOI: 10.4028/p-hkud3w

    Scopus

  • Nanodiamond/Conducting Polymer Nanocomposites for Supercapacitor Applications

    Zkria A., Ali A.M., Mahmoud I., Abdelwahab A., El Rouby W.M.A., Yoshitake T.

    Engineering Materials  2022年    ISSN:16121317

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    Supercapacitors, known as electrochemical capacitors, are very attractive as energy storage devices due to their high-power density (up to 410 kW kg−1), their unique ability to undergo charge/discharge quickly and their long cycling life (that could reach 4105 cycles). Efforts have been dedicated to develop various carbon-based nanomaterials for energy storage, specially supercapacitors. Carbon-based materials and conducting polymers (ie; Polypyrrole and Polyaniline) are considered the most promising candidates for capacitive materials, as they offer high charging capacity through diverse mechanisms. Among these carbon-based materials are nano-crystalline diamond (NCD) films, which were widely studied during the past decades due to their special features like; short-range sp3 bonded carbon atoms and large surface to volume ratio. Artificial fabrication of NCD films was developed using various techniques like; high-pressure high-temperature (HPHT), chemical vapor deposition, plasma-discharge-stimulated, laser ablation,hot-filament technique,, and coaxial arc plasma deposition. Although carbon-based nanomaterials display good stability in energy storage applications, the capacitance values are yet limited by the microstructures within the materials; Therefore, their nanocomposites with conducting polymers provide higher performance and improved properties. This chapter aims to summarize and discuss the recent synthetic developments of nanocrystalline diamond/conducting polymer nanocomposites, and their applications to energy storage and supercapacitor.

    DOI: 10.1007/978-3-030-94319-6_32

    Scopus

講演・口頭発表等

  • Enhanced corrosion resistance of Mg-based alloys by Quenched diamond coatings 招待 国際共著 国際会議

    Abdelrahman Zkria Ahmed

    International Thin Films Conference (TACT)-2025  2025年10月  Taiwan Association for Coating and Thin Film Technology

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    開催年月日: 2025年10月

    記述言語:英語   会議種別:口頭発表(招待・特別)  

    開催地:GIS TAIPEI TECH Convention Center   国名:台湾  

  • Quenched-produced Diamond for Environmental Applications 招待 国際共著 国際会議

    Abdelrahman Zkria Ahmed

    The 5th International Conference of Chemical, Energy and Environmental Engineering - ICCEEE 2025The 5th International Conference of Chemical, Energy and Environmental Engineering - ICCEEE 2025  2025年7月  Egypt-Japan university of Science and technology

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    開催年月日: 2025年7月

    記述言語:英語   会議種別:口頭発表(招待・特別)  

    開催地:Egypt-Japan university of Science and technology   国名:エジプト・アラブ共和国  

    その他リンク: https://icceee.ejust.edu.eg/

  • Nanodiamond Composite Films Via Physical Vapor Deposition: Pioneering Sustainable Manufacturing 国際共著 国際会議

    Abdelrahman Zkria Ahmed

    ACS Qatar Chapter/RSC MEA Conference  2024年11月  American Chemical Society

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    開催年月日: 2024年11月

    記述言語:英語   会議種別:口頭発表(一般)  

    開催地:Doha, Qatar  

  • Bridging Japan & Arab Region in STI (Study and Research in Japan) 招待 国際会議

    Abdelrahman Zkria

    Qatar- Japan Research Forum  2024年1月  Qatar University

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    開催年月日: 2024年1月

    記述言語:英語   会議種別:口頭発表(招待・特別)  

    開催地:Qatar University   国名:その他  

    Japan is known as the land of sunrise, it enjoys a rich cultural heritage with unique characteristics and world-class career opportunities. In recent years, the Japanese government has increasingly sought to attract highly-skilled and well-educated foreigners who can contribute to its high-tech and strong economy. In this session, we will listen to expert tips for studying in Japan through governmental and private scholarships and also the skills required for the Japanese job market. We will shed the light on the activities of internationalization at Kyushu University, and highlight the recent research in diamond materials field.

  • Growth of Quenched-produced Diamond (Q-dia.) by Coaxial Arc Plasma Deposition (CAPD) for Biomedical Applications 国際会議

    Abdelrahman Zkria

    International Thin Films Conference (TACT 2023) Taipei, Taiwan  2023年11月 

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    開催年月日: 2023年11月

    記述言語:英語   会議種別:公開講演,セミナー,チュートリアル,講習,講義等  

    開催地:National Taipei University of Technology, Taipei, Taiwan   国名:台湾  

    Recently, our research group has successfully fabricated a new metastable solid-state of carbon, namely quenched-produced diamond (Q-dia), using coaxial arc plasma deposition (CAPD) at room temperature and low pressure. We have realized the adhesion of Q-dia films on Ti substrates at room temperature, using a hybrid design of ion etching gun and coaxial arc plasma deposition (IG/CAPD). By employing in situ Ar+ ion etching, we efficiently eliminated the native titanium oxide layer (TiO2) that constrained the adhesion of Q-dia films on Ti at room temperature and ensured further safeguarding against oxidation before film deposition.

    その他リンク: https://tact2023.conf.tw/site/page.aspx?pid=901&sid=1481&lang=en

  • Structural evolution of nanostructure carbon films by ultrafast pulsed laser annealing 招待

    Abdelrahman Zkria

    30th International Conference on Diamond and Carbon Materials  2019年9月 

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    開催年月日: 2023年7月

    記述言語:英語  

    開催地:Seville, Spain   国名:スペイン  

    その他リンク: https://www.elsevier.com/events/conferences/international-conference-on-diamond-and-carbon-materials/about/previous-events

  • Thermal stability of nanodiamond composite films prepared by arc plasma deposition method 国際会議

    Abdelrahman Zkria

    International Thin Films Conference (TACT 2021) Taipei, Taiwan  2021年11月 

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    開催年月日: 2021年11月

    記述言語:英語  

    開催地:Taipei, Taiwan   国名:台湾  

    その他リンク: https://tact2021.conf.tw/site/page.aspx?pid=901&sid=1365&lang=en

  • Application of laser-induce doping for singlecrystalline diamond 国際会議

    Abdelrahman Zkria

    Material Research Society (MRS)  2019年11月 

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    開催年月日: 2018年11月

    記述言語:英語   会議種別:口頭発表(一般)  

    開催地:Hynes Convention Center, Boston   国名:アメリカ合衆国  

    その他リンク: https://www.mrs.org/meetings-events/fall-meetings-exhibits

  • Nanodiamond films prepared by Coaxial Arc Plasma Deposition and their various applications 招待 国際共著 国際会議

    Abdelrahman Zkria Ahmed

    9th International Exchange and Innovation Conference on Engineering & Sciences  2023年10月  Faculty of Engineering Sciences, Kyushu University

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    開催年月日: 2023年10月

    記述言語:英語   会議種別:口頭発表(基調)  

    開催地:C-Cube Hall, Faculty of Engineering Sciences, Kyushu University   国名:日本国  

  • Application of nanosecond laser annealing to diamond materials

    Abdelrahman Zkria

    Japan Society of Applied Physics  2023年3月 

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    開催年月日: 2023年7月

    記述言語:英語  

    開催地:Sophia University, Tokyo   国名:日本国  

▼全件表示

MISC

所属学協会

学術貢献活動

  • Scientific committee-International Conference of Chemical, Energy and Environmental Engineering

    役割:パネル司会・セッションチェア等, 審査・評価

    Egypt-Japan university of Science and technology   2023年11月 - 現在

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    種別:大会・シンポジウム等 

  • Asian APC Conference-Organization Committee 国際学術貢献

    役割:パネル司会・セッションチェア等

    Japan Society for Applied Physics-Kyushu Chapter  ( Kyushu University Japan ) 2023年11月

     詳細を見る

    種別:学会・研究会等 

共同研究・競争的資金等の研究課題

  • New Generation of Multielement-Doped Nanodiamond Thin Films by Coaxial Arc Plasma Deposition as Robust NanoCatalysts for Electroreduction of CO2 to C2+ Products 国際共著

    2023年8月 - 2024年9月

    Marubeni company-Qatar  Qatar-Japan Research Collaboration program (QJRC) 

    吉武 剛

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    担当区分:研究分担者  資金種別:科研費以外の競争的資金

    This is a Joint- project supported with Qatar University under the Qatar-Japan Research Collaboration program (QJRC-2) funded by funded by Marubeni, which brings together Qatar University and Japanese Universities to collaborate on research topics of mutual interest. In this project, we are developing Multielement-Doped Nanodiamond Thin Films by Coaxial Arc Plasma Deposition for the Electroreduction of CO2 to C2+ Products.

  • AY2023 Researcher Network Formation Promotion Program

    2023年7月 - 2024年3月

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    担当区分:研究代表者  資金種別:その他産学連携による資金

  • Multielement-Doped Nanodiamond as Robust NanoCatalysts for Electroreduction of CO2

    2023年 - 2024年

    QATAR-JAPAN RESEARCH COLLABORATION

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    担当区分:研究代表者  資金種別:受託研究

  • A new physical approach to form single-photon sources in nanodiamonds for quantum applications

    2022年4月 - 2023年3月

    Kyushu University 

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    担当区分:研究代表者 

  • A new physical approach to form single-photon sources in nanodiamond for quantum applications

    2022年 - 2024年

    2022 Research Start Program-Young Researcher

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    担当区分:研究代表者  資金種別:学内資金・基金等

  • Ultrananocrystalline diamond films for quantum center applications

    2021年4月 - 2023年3月

    The Japan Society for the Promotion of Science, Japan 

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    担当区分:研究分担者 

  • Ultrananocrystalline diamond films preparation and the application to Photovoltaics and hard coating

    2019年4月 - 2021年3月

    The Japan Society for the promotion of Science, Japan 

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    担当区分:研究分担者 

  • Development of nanocarbon thin films for all-carbon photovoltaics

    2017年11月 - 2019年11月

    The Japan Society for the Promotion of Science, Japan 

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    担当区分:研究代表者 

  • Development of nanocarbon thin films for all-carbon photovoltaics

    2017年 - 2019年

    日本学術振興会  海外特別研究員

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    資金種別:共同研究

▼全件表示

教育活動概要

  • From 2024, Dr. Abdelrahman is working for the Department of Internationalization and Future Conception (IFC) at the Faculty of Engineering Science to promote the international educational activities. Before that, he worked for the Center for Japan-Egypt Cooperation in Science and Technology (EJUST Center). He was contributing to the supervision and teaching of domestic and international students at the Japan-Egypt University of Science and Technology (E-JUST) supported by TICAD-JICA Scholarship.

担当授業科目

  • Fundamentals of Green Energy and Engineering

    2024年12月   秋学期

  • Academic writing for postgraduate students

    2024年10月 - 現在   通年

FD参加状況

  • 2025年3月   役割:司会   名称:Japan-Taiwan Symposium on Anticorrosion Coating

    主催組織:部局

  • 2024年8月   役割:講演   名称:IGSES, IEI Program information session

    主催組織:部局

  • 2023年10月   役割:講演   名称:9th International Exchange and Innovation Conference on Engineering & Sciences (IEICES 2023)

    主催組織:部局

他大学・他機関等の客員・兼任・非常勤講師等

  • 2025年  National Taiwan University   区分:非常勤講師  国内外の区分:国外 

    学期、曜日時限または期間:From 11 February to 21 March 2025

国際教育イベント等への参加状況等

  • 2025年3月

    Faculty of Engineering Sciences, Kyushu University

    Japan-Taiwan Symposium on Anticorrosion Coating

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    開催国・都市名:Japan

    参加者数:30

  • 2025年3月

    CAMPUS Asia, Kyushu University

    CAMPUS Asia + EEST Reunion Symposium 2025

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    開催国・都市名:Japan

  • 2025年1月

    Faculty of Engineering, Kyushu University

    Sakura Science Program

      詳細を見る

    開催国・都市名:Japan

  • 2025年1月

    Kyoto University

    4th IAfP: Africa-Japan University Education Exchange Meeting

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    開催国・都市名:Japan

    参加者数:30

  • 2024年10月

    Qatar University

    Qatar-Japan Research Forum

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    開催国・都市名:State of Qatar

    参加者数:150

  • 2024年10月

    Kyushu University Institute for Asian and Oceanian Studies (Q-AOS)

    Egypt & Japan Academic Collaboration Forum/KYUDAI NOW in Egypt

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    開催国・都市名:Egypt

    参加者数:800

  • 2024年2月

    Faculty of Engineering Sciences, Kyushu University

    Sakura Science Program

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    開催国・都市名:Japan

  • 2023年1月

    Egypt-Japan University of Science and Technology (E-JUST)

    Research and Study in Japan Forum

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    開催国・都市名:Egypt

  • 2022年9月

    The Arab-German Young Academy of Sciences and Humanities (AGYA)

    2nd Practical AGYA Training: Improving Academic and Professional Skills

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    開催国・都市名:Egypt

    参加者数:300

▼全件表示

指導学生の受賞

  • TSMC International Internship

    授与年月:2025年8月

    受賞学生の区分:修士   受賞学生氏名:Mahmoud Youssef Talaat

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その他教育活動及び特記事項

  • 2024年  その他特記事項  さくらサイエンスプログラム

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    Co-organized the Sakura Science Program funded by JST. In this program ten international academics and students from three different countries (Malaysia, Qatar, Egypt) visited Kyushu University for one week.

社会貢献・国際連携活動概要

  • * 九州大学とエジプト日本科学技術大学(E-JUST)の国際協力の推進
    * 国立台湾大学とのコラボレーションを開始
    * カタール大学との日カタール研究協力プログラムの開始

外国人研究者等の受け入れ状況

  • Faculty of Sciences, South Valley University

    受入れ期間: 2025年8月 - 2026年1月   (期間):1ヶ月以上

    国籍:エジプト・アラブ共和国

    専業主体:外国政府・外国研究機関・国際機関

  • Faculty of Energy Engineering, Aswan University

    受入れ期間: 2024年11月 - 2025年5月   (期間):1ヶ月以上

    国籍:エジプト・アラブ共和国

    専業主体:外国政府・外国研究機関・国際機関

  • Egypt-Japan University of Science and Technology (E-JUST)

    受入れ期間: 2024年9月 - 2025年6月   (期間):1ヶ月以上

    国籍:エジプト・アラブ共和国

    専業主体:外国政府・外国研究機関・国際機関

  • Egypt-Japan University of Science and Technology (E-JUST)

    受入れ期間: 2024年4月 - 2025年1月   (期間):1ヶ月以上

    国籍:エジプト・アラブ共和国

    専業主体:外国政府・外国研究機関・国際機関

海外渡航歴

  • 2025年9月

    滞在国名1:アイスランド共和国   滞在機関名1:University of Iceland

  • 2025年2月 - 2025年3月

    滞在国名1:台湾   滞在機関名1:National Taiwan University

    滞在国名2:台湾   滞在機関名2:National Tsing Hua University

    滞在国名3:台湾   滞在機関名3:Feng Chia University

    滞在国名(その他):Taiwan, Province of China   滞在機関名(その他):Industrial Technology Research Institute (ITRI)

  • 2024年1月

    滞在国名1:エジプト・アラブ共和国   滞在機関名1:Egypt-Japan University for Science and Technology (E-JUST)

    滞在機関名2:Alexandria University

    滞在機関名3:Aswan University

  • 2018年11月 - 2019年3月

    滞在国名1:アメリカ合衆国   滞在機関名1:North Carolina State University

    滞在国名2:オーストリア共和国   滞在機関名2:Graz University

    滞在国名3:エジプト・アラブ共和国   滞在機関名3:Aswan University

  • 2010年9月 - 2011年7月

    滞在国名1:オーストリア共和国   滞在機関名1:Graz University

学内運営に関わる各種委員・役職等

  • その他 Associate Professor (准教授)