九州大学-研究者情報 [山下尚人 (助教) システム情報科学研究院 I&Eビジョナリー特別部門]

山下尚人（やましたなおと）

データ更新日：2023.06.19

助教　／　システム情報科学研究院 I&Eビジョナリー特別部門

原著論文

1.	M. Otaka, T. Arima, J. Lai, K. Ikeda, K. Kamataki, N. Yamashita, T. Okumura, N. Itagaki, K. Koga, M. Shiratani, Spatio-temporal measurements Ar 2p1 excitation rates and optical emission spectroscopy by capacitively coupled Ar and Ne mixed gas plasma, MRS Adv., 10.1557/s43580-022-00306-2, 2022.07, [URL].
2.	S. Ono, S. H. Hwang, T. Okumura, K. Kamataki, N. Yamashita, N. Itagaki, K. Koga, M. Shiratani, J. S. Oh, S. Takabayashi, T. Nakatani, Raman spectral analysis of the as-deposited aC: H films prepared by CH4+ Ar plasma CVD, MRS Adv., 10.1557/s43580-022-00310-6, 7, 718–722, 2022.07, [URL].
3.	T. Okumura, P. Attri, K. Kamataki, N. Yamashita, Y. Tsukada, N. Itagaki, M. Shiratani, Y. Ishibashi, K. Kuchitsu, K. Koga, Detection of NO3− introduced in plasma-irradiated dry lettuce seeds using liquid chromatography-electrospray ionization quantum mass spectrometry (LC-ESI QMS), Sci. Rep., 10.1038/s41598-022-16641-1, 12, 12525, 2022.07, [URL].
4.	K. Kamataki, D. Nagamatsu, T. Yang, K. Abe, A. Yamamoto, I. Nagao, T. Arima, M. Otaka, Y. Yamamoto, D. Yamashita, T. Okumura, N. Yamashita, N. Itagaki, K. Koga, M. Shiratani, Effects of amplitude modulated discharge on growth of nanoparticles in TEOS/O2/Ar capacitively coupled plasma, AIP Adv, 10.1063/5.0097691, 12, 8, 085220, 2022.08, [URL].
5.	K. Kamataki, D. Nagamatsu, T. Yang, K. Abe, A. Yamamoto, I. Nagao, T. Arima, M. Otaka, Y. Yamamoto, D. Yamashita, T. Okumura, N. Yamashita, N. Itagaki, K. Koga, M. Shiratani, Effects of amplitude modulated discharge on growth of nanoparticles in TEOS/O2/Ar capacitively coupled plasma, AIP Adv., 10.1063/5.0097691, 12, 085220, 2022.08, [URL].
6.	K. Abe, K. Kamataki, A. Yamamoto, I. Nagao, M. Otaka, D. Yamashita, T. Okumura, N. Yamashita, N. Itagaki, K . Koga, M. Shiratani, Effects of amplitude modulated capacitively coupled discharge Ar plasma on kinetic energy and angular distribution function of ions impinging on electrodes:particle-in-cell/Monte Carlo collision model simulation, Jpn. J. Appl. Phys., 10.35848/1347-4065/ac7626, 61, 10, 106003, 2022.09, [URL].
7.	K. Koga, P. Attri, T. Okumura, T. Anan, T. Nakao, K. Kamataki, N. Yamashita, N. Itagaki, M. Shiratani, Role of short-lived nitrogen species generated at low-pressure RF plasma on the germination and seedling growth, Bull. Am. Phys. Soc., 2022.10, [URL].
8.	K. Kamataki, T. Sato, K. Tomita, P. Yimin, D. Yamashita, N. Yamashita, T. Okumura, N. Itagaki, K. Koga, M. Shiratani, Measurements of strength and fluctuation of 2D electric fields in plasmas using a fine particle trapped with laser tweezers, Bull. Am. Phys. Soc., 2022.10, [URL].
9.	I. Nagao, A. Yamamoto, Y. Yamamoto, K. Kamataki, T. Okumura, N. Yamashita, N. Itagaki, K. Koga, M. Shiratani, Effects of amplitude modulation discharge on behavior of oxygen ions in Ar/O2 capacitively coupled plasma studied by particle-in-cell/Monte Carlo collision model, Bull. Am. Phys. Soc., 2022.10, [URL].
10.	A. M. Nurut, N. Yamashita, K. Kamataki, K. Koga, N. Itagaki, M. Shiratani, Control of magnetic transition of ZnO: Co grown by RF-sputter using post-annealing, ICIEE, 10.1109/ICIEE55596.2022.10010108, 2022.10, [URL].
11.	M. Otaka, T. Arima, J. Lai, K. Ikeda, K. Kamataki, N. Yamashita, T. Okumura, N. Itagaki, K. Koga, M. Shiratani, Pressure dependence on spatio-temporal distribution of excitation rates of Ar 2p1 and Ne 2p1 in Ar and Ar/Ne capacitively coupled plasmas, Bull. Am. Phys. Soc., 2022.10, [URL].
12.	T. Anan, T. Nakao, T. Okumura, P. Attri, K. Kamataki, N. Yamashita, N. Itagaki, K. Koga, M. Shiratani, Effect of plasma irradiation on germination of lettuce seeds with fluctuating dormancy, Bull. Am. Phys. Soc., 2022.10, [URL].
13.	M. Shiratani, D. Takahashi, N. Yamashita, N. Itagaki, Sputter epitaxy of Mg-doped ZnO films on sapphire substrates using inverted Stranski-Krastanov mode, Bull. Am. Phys. Soc., 2022.10, [URL].
14.	S. Ono, T. Okumura, K. Kamataki, N. Yamashita, N. Itagaki, K. Koga, M. Shiratani, Process analysis of cracking aC: H/CNP/aC: H sandwich films under stress using nanoindentation, Bull. Am. Phys. Soc., 2022.10, [URL].
15.	T. Okumura, T. Anan, P. Attri, Y. Tsukada, K. Kamataki, N. Yamashita, N. Itagaki, K. Koga, M. Shiratani, Y. Ishibashi, Plasma irradiation-introduced RONS amount into plant seeds and their response analysis, Bull. Am. Phys. Soc., 2022.10, [URL].
16.	R. Narishige, N. Yamashita, K. Kamataki, T. Okumura, K. Koga, M. Shiratani, H. Yabuta, N. Itagaki , Effects of substrate surface polarity on heteroepitaxial growth of pseudobinary ZnO–InN alloy films on ZnO substrates(Invited), J. Mater. Res., 10.1557/s43578-022-00827-4, 2022.11, [URL].
17.	I. Nagao, K. Kamataki, A. Yamamoto, M. Otaka, Y. Yamamoto, D. Yamashita, N. Yamashita, T. Okumura, N. Itagaki, K. Koga, M. Shiratani, One-dimensional particle-in-cell/Monte Carlo collision simulation for investigation of amplitude modulation effects in RF capacitive discharges, MRS Adv., 10.1557/s43580-022-00417-w, 7, 911-917, 2022.12, [URL].
18.	N. Yamashita, R. Mitsuishi, Y. Nakamura, K. Takeda, M. Hori, K. Kamataki, T. Okumura, K. Koga, M. Shiratani, Role of insoluble atoms in the formation of a three-dimensional buffer layer in inverted Stranski–Krastanov mode, J. Mater. Res, 10.1557/s43578-022-00886-7, 1-8, 2023.01, [URL].
19.	M. N. Agusutrisno, R. Narishige, K. Kamataki, T. Okumura, N. Itagaki, K. Koga, M. Shiratani, N. Yamashita, Control of Inhomogeneity and Magnetic Properties of ZnO:Co Films Grown by Magnetron Sputtering Using Nitrogen, Mater Sci Semicond Process, 10.1016/j.mssp.2023.107503, 162, 107503, 2023.08, [URL].
20.	K. Kamataki, Y. Sasaki, I. Nagao, D. Yamashita, T. Okumura, N. Yamashita, N. Itagaki, K. Koga, M. Shiratani, Low-temperature fabrication of silicon nitride thin films from a SiH4+N2 gas mixture by controlling SiNx nanoparticle growth in multi-hollow remote plasma chemical vapor deposition, Mater Sci Semicond Process, 10.1016/j.mssp.2023.107613, 164, 107613, 2023.09, [URL].
21.	Michihiro Otaka, Toshiaki Arima, Jiansyun Lai, Kizuki Ikeda, Kunihiro Kamataki, Naoto Yamashita, Takamasa Okumura, Naho Itagaki, Kazunori Koga, Masaharu Shiratani, Spatio-temporal measurements Ar 2p1 excitation rates and optical emission spectroscopy by capacitively coupled Ar and Ne mixed gas plasma, MRS Advances, 10.1557/s43580-022-00306-2, 7, 31, 918-922, 2022.07.
22.	N. Yamashita, E. Shigematsu, S. Honda, R. Ohshima, M. Shiraishi, Y. Ando, Realization of efficient tuning of the Fermi level in iron-based ferrimagnetic alloys, Physical Review Materials, 10.1103/physrevmaterials.6.104405, 6, 10, 104405, 2022.10, The Stoner criterion allows only three single elements possessing room-temperature (RT) ferromagnetism: cobalt (Co), nickel (Ni), and iron (Fe). Although these three elements have played central roles in magnetism-based materials, their large work function (4.5∼5.2eV) is becoming a non-negligible obstacle for realization of spin devices using nonmetallic materials with finite energy gaps, because injection of electron spins into these nonmetallic materials is strongly hampered due to the large Schottky barrier height. Hence, a novel ferromagnetic or ferrimagnetic material simultaneously possessing RT ferromagnetism or ferrimagnetism and high Fermi energy is strongly required. Here, we show that an Fe-based alloy, iron-gadolinium (FeGd), allows circumvention of the obstacle. Surprisingly, only 20% of Gd incorporation in Fe dramatically modulates the Fermi energy from -4.8 to -3.0 eV, which is the largest modulation in all metallic alloys reported thus far. The coexistence of ferrimagnetism and nonzero spin polarization at RT of FeGd supports its abundant potential for future applications in low-carrier-density materials such as monolayer, organic, and nondegenerate inorganic semiconductors..
23.	Shinjiro Ono, Sung Hwa Hwang, Takamasa Okumura, Kunihiro Kamataki, Naoto Yamashita, Naho Itagaki, Kazunori Koga, Masaharu Shiratani, Jun-Seok Oh, Susumu Takabayashi, Tatsuyuki Nakatani, Raman spectral analysis of the as-deposited a-C:H films prepared by CH4+ Ar plasma CVD, MRS ADVANCES, 10.1557/s43580-022-00310-6, 7, 30, 718-722, 2022.11, Applicability of precise Raman spectral analysis of a-C:H films deposited using a plasma chemical vapor deposition (CVD) method has been discussed based on the sensitivity to initial conditions in peak separation. The spectral analysis offers to deconvolute the spectra into five peaks, while the as-deposited films prepared by plasma CVD is difficult to the five-peak separation. We found the peak position and the peak height ratio of the D-band to the G(+)-band can be employed to discuss the structure of the as-deposited films. We examined the structural difference between the films deposited at the powered electrode and that at grounded electrode. We found graphene nanoribbon-like structures may be formed in the films deposited on the grounded substrate. This result suggests that the substrate position is an important factor to form the graphene nanoribbon-like structure..
24.	Iori Nagao, Kunihiro Kamataki, Akihiro Yamamoto, Michihiro Otaka, Yuma Yamamoto, Daisuke Yamashita, Naoto Yamashita, Takamasa Okumura, Naho Itagaki, Kazunori Koga, Masaharu Shiratani, One-dimensional particle-in-cell/Monte Carlo collision simulation for investigation of amplitude modulation effects in RF capacitive discharges, MRS Advances, 10.1557/s43580-022-00417-w, 7, 31, 911-917, 2022.12.
25.	Daichi Takahashi, Naoto Yamashita, Daisuke Yamashita, Takamasa Okumura, Kunihiro Kamataki, Kazunori Koga, Masaharu Shiratani, Naho Itagaki, Epitaxial growth of Zn1−xMgxO films on sapphire substrates via inverted Stranski-Krastanov mode using magnetron sputtering, MRS Advances, 10.1557/s43580-022-00234-1, 2022.02.
26.	Ryota Narishige, Naoto Yamashita, Kunihiro Kamataki, Takamasa Okumura, Kazunori Koga, Masaharu Shiratani, Hisato Yabuta, Naho Itagaki, Effects of substrate surface polarity on heteroepitaxial growth of pseudobinary ZnO–InN alloy films on ZnO substrates, Journal of Materials Research, 10.1557/s43578-022-00827-4, 38, 7, 1803-1812, 2022.11.
27.	Kohei Abe, Kunihiro Kamataki, Akihiro Yamamoto, Iori Nagao, Michihiro Otaka, Daisuke Yamashita, Takamasa Okumura, Naoto Yamashita, Naho Itagaki, Kazunori Koga, Masaharu Shiratani, Effects of amplitude modulated capacitively coupled discharge Ar plasma on kinetic energy and angular distribution function of ions impinging on electrodes: particle-in-cell/Monte Carlo collision model simulation, Japanese Journal of Applied Physics, 10.35848/1347-4065/ac7626, 61, 10, 106003-106003, 2022.09, Abstract We investigated the effects of amplitude modulated (AM) capacitively coupled Ar discharge plasma on the ion energy distribution function (IEDF) and the ion angular distribution function (IADF) incident on electrodes using the particle-in-cell/Monte Carlo collision model. For AM discharge, the electron density and electron temperature and the kinetic energy and angle of ions incident on the ground electrode change periodically with AM frequency, whereas ones for continuous wave discharge are almost constant. For AM discharge, the plasma had hysteresis characteristics. The peak energy of IEDF varies from 53 to 135 eV and the FWHM of IADF varies from 1.82 to 3.34 degrees for gas pressure 10mTorr, the peak-to-peak input voltage 400 V and AM level of 50%. The variation width of the peak energy of IEDF and FWHM of IADF increases with the AM level. These effects of AM method discharge are more noticeable at lower pressures. Thus, the AM discharge offers a way to control simultaneously IEDF and IADF, which opens a new avenue for plasma processes such as an ALD-like PECVD..
28.	Naoto Yamashita, Ryo Mitsuishi, Yuta Nakamura, Keigo Takeda, Masaru Hori, Kunihiro Kamataki, Takamasa Okumura, Kazunori Koga, Masaharu Shiratani, Role of insoluble atoms in the formation of a three-dimensional buffer layer in inverted Stranski–Krastanov mode, Journal of Materials Research, 10.1557/s43578-022-00886-7, 38, 5, 1178-1185, 2023.01.
29.	D. Takahashi, N. Yamashita, D. Yamashita, T. Okumura, K. Kamataki, K. Koga, M. Shiratani, N. Itagaki, Epitaxial Growth of Zn1-xMgxO Films on Sapphire Substrates via Inverted Stranski-Krastanov Mode Using Magnetron Sputtering, MRS Adv., 10.1557/s43580-022-00234-1, 2022.02, [URL].
30.	Yuta Nakamura, Naoto Yamashita, Kunihiro Kamataki, Takamasa Okumura, Kazunori Koga, Masaharu Shiratani, Naho Itagaki, Growth of Single-Crystalline ZnO Films on 18%-Lattice-Mismatched Sapphire Substrates Using Buffer Layers with Three-Dimensional Islands, Crystal Growth & Design, 10.1021/acs.cgd.2c00145, 22, 6, 3770-3777, 2022.06.
31.	Soobeom Lee, Hayato Koike, Minori Goto, Shinji Miwa, Yoshishige Suzuki, Naoto Yamashita, Ryo Ohshima, Ei Shigematsu, Yuichiro Ando, Masashi Shiraishi, Synthetic Rashba spin–orbit system using a silicon metal-oxide semiconductor, Nature Materials, 10.1038/s41563-021-01026-y, 20, 9, 1228-1232, 2021.06.
32.	N. Yamashita, S. Lee, R. Ohshima, E. Shigematsu, H. Koike, Y. Suzuki, S. Miwa, M. Goto, Y. Ando, M. Shiraishi, Investigation of the thermal tolerance of silicon-based lateral spin valves, Scientific Reports, 10.1038/s41598-021-90114-9, 11, 1, 10583, 2021.05, AbstractImprovement in the thermal tolerance of Si-based spin devices is realized by employing thermally stable nonmagnetic (NM) electrodes. For Au/Ta/Al electrodes, intermixing between Al atoms and Au atoms occurs at approximately 300 °C, resulting in the formation of a Au/Si interface. The Au–Si liquid phase is formed and diffuses mainly along an in-plane direction between the Si and AlN capping layers, eventually breaking the MgO layer of the ferromagnetic (FM) metal/MgO electrodes, which is located 7 µm away from the NM electrodes. By changing the layer structure of the NM electrode from Au/Ta/Al to Au/Ta, the thermal tolerance is clearly enhanced. Clear spin transport signals are obtained even after annealing at 400 °C. To investigate the effects of Mg insertion in FM electrodes on thermal tolerance, we also compare the thermal tolerance among Fe/Co/MgO, Fe/Co/Mg/MgO and Fe/Co/MgO/Mg contacts. Although a highly efficient spin injection has been reported by insertion of a thin Mg layer below or above the MgO layer, these thermal tolerances decrease obviously..
33.	N. Yamashita, S. Lee, R. Ohshima, E. Shigematsu, H. Koike, Y. Suzuki, S. Miwa, M. Goto, Y. Ando, M. Shiraishi, Enhancement of spin signals by thermal annealing in silicon-based lateral spin valves, AIP Advances, 10.1063/5.0022160, 10, 9, 095021-095021, 2020.09.
34.	Naoto Yamashita, Yuichiro Ando, Hayato Koike, Shinji Miwa, Yoshishige Suzuki, Masashi Shiraishi, Thermally Generated Spin Signals in a Nondegenerate Silicon Spin Valve, Physical Review Applied, 10.1103/physrevapplied.9.054002, 9, 5, 054002, 2018.05.
35.	Soobeom Lee, Naoto Yamashita, Yuichiro Ando, Shinji Miwa, Yoshishige Suzuki, Hayato Koike, Masashi Shiraishi, Investigation of spin scattering mechanism in silicon channels of Fe/MgO/Si lateral spin valves, Applied Physics Letters, 10.1063/1.4982966, 110, 19, 192401-192401, 2017.05.

九大関連コンテンツ

pure2017年10月2日から、「九州大学研究者情報」を補完するデータベースとして、Elsevier社の「Pure」による研究業績の公開を開始しました。

QIR　九州大学学術情報リポジトリシステム情報科学研究院

システム情報科学研究院


	※ 研究者情報全体を検索する場合は右端の「すべて」を選択して下さい。