Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1103/PhysRevB.108.075408

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.ultramic.2023.113747

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1103/PhysRevB.107.165421

Language：English   Publishing type：Research paper (scientific journal)  

Multilayer hexagonal boron nitride (hBN) can be used to preserve the intrinsic physical properties of other two-dimensional materials in device structures. However, integrating the material into large-scale two-dimensional heterostructures remains challenging due to the difficulties in synthesizing high-quality large-area multilayer hBN and combining it with other two-dimensional material layers of the same scale. Here we show that centimetre-scale multilayer hBN can be synthesized on iron–nickel alloy foil by chemical vapour deposition, and then used as a substrate and as a surface-protecting layer in graphene field-effect transistors. We also develop an integrated electrochemical transfer and thermal treatment method that allows us to create high-performance graphene/hBN heterostacks. Arrays of graphene field-effect transistors fabricated by conventional and scalable methods show an enhancement in room-temperature carrier mobility when hBN is used as an insulating substrate, and a further increase—up to a value of 10,000 cm2 V−1 s−1—when graphene is encapsulated with another hBN sheet.

DOI： 10.1038/s41928-022-00911-x

Other Link： https://www.nature.com/articles/s41928-022-00911-x

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1103/PhysRevApplied.19.014015

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.carbon.2022.09.021

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/D2NA00479H

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsnano.2c03997

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1080/14686996.2022.2062576

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsanm.1c03928

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acs.nanolett.1c03689

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1002/adma.202105898

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.cej.2020.127721

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsanm.1c00192

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsaelm.0c00601

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/D0CP02652B

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/acsnano.0c00645

Language：English   Publishing type：Research paper (scientific journal)  

Monolayers of transition metal dichalcogenides (TMDCs) have attracted a great interest for post-silicon electronics and photonics due to their high carrier mobility, tunable bandgap, and atom-thick 2D structure. With the analogy to conventional silicon electronics, establishing a method to convert TMDC to p- and n-type semiconductors is essential for various device applications, such as complementary metal-oxide-semiconductor (CMOS) circuits and photovoltaics. Here, a successful control of the electrical polarity of monolayer WSe₂ is demonstrated by chemical doping. Two different molecules, 4-nitrobenzenediazonium tetrafluoroborate and diethylenetriamine, are utilized to convert ambipolar WSe₂ field-effect transistors (FETs) to p- and n-type, respectively. Moreover, the chemically doped WSe₂ show increased effective carrier mobilities of 82 and 25 cm² V⁻¹s⁻¹ for holes and electrons, respectively, which are much higher than those of the pristine WSe₂. The doping effects are studied by photoluminescence, Raman, X-ray photoelectron spectroscopy, and density functional theory. Chemically tuned WSe₂ FETs are integrated into CMOS inverters, exhibiting extremely low power consumption (≈0.17 nW). Furthermore, a p-n junction within single WSe₂ grain is realized via spatially controlled chemical doping. The chemical doping method for controlling the transport properties of WSe₂ will contribute to the development of TMDC-based advanced electronics.

DOI： 10.1002/adma.201903613

Language：English   Publishing type：Research paper (scientific journal)  

Hexagonal boron nitride (h-BN), an insulating two-dimensional (2D) layered material, has attracted increasing interest due to its electrical screening effect, high-temperature-resistant gas barrier properties, and other unique applications. However, the presence of grain boundaries (GBs) in h-BN is a hindrance to obtain these properties. Here, we demonstrate the epitaxial growth of monolayer h-BN by chemical vapor deposition (CVD) on Ni(111) thin films deposited on c-plane sapphire. The Ni(111) films showed higher thermal stability than Cu(111) and Cu-Ni(111) alloy films, allowing us to perform CVD growth at a high temperature of 1100 °C. This resulted in an increase of the h-BN grain sizes to up to 0.5 millimeter, among the highest reported so far, and in a well-defined triangular grain shape. Low-energy electron microscopy (LEEM) revealed the epitaxial relationship between h-BN and the underlying Ni(111) lattice, leading to a preferential alignment of the h-BN grains. Both the large grain size and the alignment are expected to facilitate the synthesis of h-BN with a low density of GBs. We also found that the addition of N₂ gas during the CVD improves the crystalline shape of the h-BN grains, changing from an irregular, truncated to a sharp triangle. The growth behavior of monolayer h-BN is further discussed in terms of the dependences on growth temperature and pressure, as well as on the structural evolution of the Ni metal catalyst. Our findings not only help understand the h-BN growth mechanism but also offer a new route to grow high-quality, monolayer h-BN films.

DOI： 10.1039/c9nr03525g

Language：English   Publishing type：Research paper (scientific journal)  

Multilayer hexagonal boron nitride (h-BN) is an ideal insulator for two-dimensional (2D) materials, such as graphene and transition metal dichalcogenides, because h-BN screens out influences from surroundings, allowing one to observe intrinsic physical properties of the 2D materials. However, the synthesis of large and uniform multilayer h-BN is still very challenging because it is difficult to control the segregation process of B and N atoms from metal catalysts during chemical vapor deposition (CVD) growth. Here, we demonstrate CVD growth of multilayer h-BN with high uniformity by using the Ni-Fe alloy film and borazine (B₃H₆N₃) as catalyst and precursor, respectively. Combining Ni and Fe metals tunes the solubilities of B and N atoms and, at the same time, allows one to engineer the metal crystallinity, which stimulates the uniform segregation of multilayer h-BN. Furthermore, we demonstrate that triangular WS₂ grains grown on the h-BN show photoluminescence stronger than that grown on a bare SiO₂ substrate. The PL line width of WS₂/h-BN (the minimum and mean widths are 24 and 43 meV, respectively) is much narrower than those of WS₂/SiO₂ (44 and 67 meV), indicating the effectiveness of our CVD-grown multilayer h-BN as an insulating layer. Large-area, multilayer h-BN realized in this work will provide an excellent platform for developing practical applications of 2D materials.

DOI： 10.1021/acsnano.8b03055

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Aligned growth of transition metal dichalcogenides and related two-dimensional (2D) materials is essential for the synthesis of high-quality 2D films due to effective stitching of merging grains. Here, we demonstrate the controlled growth of highly aligned molybdenum disulfide (MoS₂) on c-plane sapphire with two distinct orientations, which are highly controlled by tuning sulfur concentration. We found that the size of the aligned MoS₂ grains is smaller and their photoluminescence is weaker as compared with those of the randomly oriented grains, signifying enhanced MoS₂-substrate interaction in the aligned grains. This interaction induces strain in the aligned MoS₂, which can be recognized from their high susceptibility to air oxidation. The surface-mediated MoS₂ growth on sapphire was further developed to the rational synthesis of an in-plane MoS₂-graphene heterostructure connected with the predefined orientation. The in-plane epitaxy was observed by low-energy electron microscopy. Transmission electron microscopy and scanning transmission electron microscopy suggest the alignment of a zigzag edge of MoS₂ parallel to a zigzag edge of the neighboring graphene. Moreover, better electrical contact to MoS₂ was obtained by the monolayer graphene compared with a conventional metal electrode. Our findings deepen the understanding of the chemical vapor deposition growth of 2D materials and also contribute to the tailored synthesis as well as applications of advanced 2D heterostructures.

DOI： 10.1021/acsnano.8b04612

Language：English   Publishing type：Research paper (scientific journal)  

We demonstrate the synthesis of unique heterostructures consisting of SnS and WS₂ (or SnS and MoS₂) by two-step chemical vapor deposition (CVD). After the first CVD growth of triangular WS₂ (MoS₂) grains, the second CVD step was performed to grow square SnS grains on the same substrate. We found that these SnS grains can be grown at very low temperature with the substrate temperature of 200 °C. Most of the SnS grains nucleated from the side edges of WS₂ (MoS₂) grains, resulting in the formation of partly stacked heterostructures with a large overlapping area. The SnS grains showed doped p-type transfer character with a hole mobility of 15 cm² V^-1 s^-1, while the WS₂ and MoS₂ grains displayed n-type character with a high on/off ratio of >10⁶. The SnS-WS₂ and SnS-MoS₂ heterostructures exhibited clear rectifying behavior, signifying the formation of p-n junctions at their interfaces. This heterostructure growth combined with the low temperature SnS growth will provide a promising means to exploit two-dimensional heterostructures by avoiding possible damage to the first material.

DOI： 10.1039/c7cp06823a

Language：English   Publishing type：Research paper (scientific journal)  

Recently, research on transition metal dichalcogenides (TMDCs) has been accelerated by the development of large-scale synthesis based on chemical vapor deposition (CVD). However, in most cases, CVD-grown TMDC sheets are composed of randomly oriented grains, and thus contain many distorted grain boundaries (GBs) which deteriorate the physical properties of the TMDC. Here, we demonstrate the epitaxial growth of monolayer tungsten disulfide (WS₂) on sapphire by introducing a high concentration of hydrogen during the CVD process. As opposed to the randomly oriented grains obtained in conventional growth, the presence of H₂ resulted in the formation of triangular WS₂ grains with the well-defined orientation determined by the underlying sapphire substrate. Photoluminescence of the aligned WS₂ grains was significantly suppressed compared to that of the randomly oriented grains, indicating a hydrogen-induced strong coupling between WS₂ and the sapphire surface that has been confirmed by density functional theory calculations. Scanning transmission electron microscope observations revealed that the epitaxially grown WS₂ has less structural defects and impurities. Furthermore, sparsely distributed unique dislocations were observed between merging aligned grains, indicating an effective stitching of the merged grains. This contrasts with the GBs that are observed between randomly oriented grains, which include a series of 8-, 7-, and alternating 7/5-membered rings along the GB. The GB structures were also found to have a strong impact on the chemical stability and carrier transport of merged WS₂ grains. Our work offers a novel method to grow high-quality TMDC sheets with much less structural defects, contributing to the future development of TMDC-based electronic and photonic applications.

DOI： 10.1021/acs.chemmater.7b04149

Language：English   Publishing type：Research paper (scientific journal)  

The electrical contact is one of the main issues preventing semiconducting 2D materials to fulfill their potential in electronic and optoelectronic devices. To overcome this problem, a new approach is developed here that uses chemical vapor deposition grown multilayer graphene (MLG) sheets as flexible electrodes for WS₂ field-effect transistors. The gate-tunable Fermi level, van der Waals interaction with the WS₂, and the high electrical conductivity of MLG significantly improve the overall performance of the devices. The carrier mobility of single-layer WS₂ increases about a tenfold (50 cm² V⁻¹ s⁻¹ at room temperature) by replacing conventional Ti/Au metal electrodes (5 cm² V⁻¹ s⁻¹) with the MLG electrodes. Further, by replacing the conventional SiO₂ substrate with a thin (1 µm) parylene-C flexible film as insulator, flexible WS₂ photodetectors that are able to sustain multiple bending stress tests without significant performance degradation are realized. The flexible photodetectors exhibited extraordinarily high gate-tunable photoresponsivities, reaching values of 4500 A W⁻¹, and with very short (<2 ms) response time. The work of the heterostacked structure combining WS₂, graphene, and the very thin polymer film will find applications in various flexible electronics, such as wearable high-performance optoelectronics devices.

DOI： 10.1002/adfm.201703448

Language：English   Publishing type：Research paper (scientific journal)  

Bilayer graphene (BLG) comprises a 2D nanospace sandwiched by two parallel graphene sheets that can be used to intercalate molecules or ions for attaining novel functionalities. However, intercalation is mostly demonstrated with small, exfoliated graphene flakes. This study demonstrates intercalation of molybdenum chloride (MoCl₅) into a large-area, uniform BLG sheet, which is grown by chemical vapor deposition (CVD). This study reveals that the degree of MoCl₅ intercalation strongly depends on the stacking order of the graphene; twist-stacked graphene shows a much higher degree of intercalation than AB-stacked. Density functional theory calculations suggest that weak interlayer coupling in the twist-stacked graphene contributes to the effective intercalation. By selectively synthesizing twist-rich BLG films through control of the CVD conditions, low sheet resistance (83 Ω ▫⁻¹) is realized after MoCl₅ intercalation, while maintaining high optical transmittance (≈95%). The low sheet resistance state is relatively stable in air for more than three months. Furthermore, the intercalated BLG film is applied to organic solar cells, realizing a high power conversion efficiency.

DOI： 10.1002/adma.201702141

Language：English   Publishing type：Research paper (scientific journal)  

With the profuse amount of two-dimensional (2D) materials discovered and the improvements in their synthesis and handling, the field of 2D heterostructures has gained increased interest in recent years. Such heterostructures not only overcome the inherent limitations of each of the materials, but also allow the realization of novel properties by their proper combination. The physical and mechanical properties of graphene mean it has a prominent place in the area of 2D heterostructures. In this review, we will discuss the evolution and current state in the synthesis and applications of graphene-based 2D heterostructures. In addition to stacked and in-plane heterostructures with other 2D materials and their potential applications, we will also cover heterostructures realized with lower dimensionality materials, along with intercalation in few-layer graphene as a special case of a heterostructure. Finally, graphene heterostructures produced using liquid phase exfoliation techniques and their applications to energy storage will be reviewed.

DOI： 10.1039/c7cs00160f

Language：English   Publishing type：Research paper (scientific journal)  

Hexagonal boron nitride (h-BN), an atomically thin insulating material, shows a large band gap, mechanical flexibility, and optical transparency. It can be stacked with other two-dimensional (2D) materials through van der Waals interactions to form layered heterostructures. These properties promise its application as an insulating layer of novel 2D electronic devices due to its atomically smooth surface with a large band gap. Herein, we demonstrated the ambient-pressure chemical vapour deposition (CVD) growth of high-quality, large-area monolayer h-BN on a Cu(111) thin film deposited on a c-plane sapphire using ammonia borane (BH₃NH₃) as the feedstock. Highly oriented triangular h-BN grains grow on Cu(111), which finally coalescence to cover the entire Cu surface. Low-energy electron diffraction (LEED) measurements indicated that the hexagonal lattice of the monolayer h-BN is well-oriented along the underlying Cu(111) lattice, thus implying the epitaxial growth of h-BN, which can be applied in various 2D electronic devices.

DOI： 10.1039/c6cp08903h

Language：English   Publishing type：Research paper (scientific journal)  

In spite of recent progress of graphene growth using chemical vapor deposition, it is still a challenge to precisely control the nucleation site of graphene for the development of wafer-scale single-crystal graphene. In addition, the postgrowth patterning used for device fabrication deteriorates the quality of graphene. Herein we demonstrate the site-selective nucleation of single-crystal graphene on Cu foil based on spatial control of the local CH₄ concentration by a perforated Ni foil. The catalytically active Ni foil acts as a CH₄ modulator, resulting in millimeter-scale single-crystal grains at desired positions. The perforated Ni foil also allows to synthesize patterned graphene without any postgrowth processing. Furthermore, the uniformity of monolayer graphene is significantly improved when a plain Ni foil is placed below the Cu. Our findings offer a facile and effective way to control the nucleation of high-quality graphene, meeting the requirements of industrial processing.

DOI： 10.1021/acsnano.6b06265

Language：English   Publishing type：Research paper (scientific journal)  

Band gap opening in bilayer graphene (BLG) under a vertical electric field is important for the realization of high performance graphene-based semiconductor devices, and thus, the synthesis of uniform and large-area BLG is required. Here we demonstrate the synthesis of a highly uniform BLG film by chemical vapor deposition (CVD) over epitaxial Cu-Ni (111) binary alloy catalysts. The relative concentration of Ni and Cu as well as the growth temperature and cooling profile was found to strongly influence the uniformity of the BLG. In particular, a slow cooling process after switching off the carbon feedstock is important for obtaining a uniform second layer, covering more than 90% of the total area. Moreover, low-energy electron microscopy (LEEM) study revealed the second layer grows underneath the first layer. We also investigated the stacking order by Raman spectroscopy and LEEM and found that 70-80% of bilayer graphene has Bernal stacking. The metastable 30°-rotated orientations were also observed both in the upper and lower layers. From our experimental observations, a new growth mode is proposed; the first layer grows during the CH₄ supply on Cu-Ni alloy surface, while the second layer is segregated from the bulk alloy during the cooling process. Our work highlights the growth mechanism of BLG and offers a promising route to synthesize uniform and large-area BLG for future electronic devices.

DOI： 10.1021/acs.chemmater.6b01137

Language：English   Publishing type：Research paper (scientific journal)  

The presence of grain boundaries in two-dimensional (2D) materials is known to greatly affect their physical, electrical, and chemical properties. Given the difficulty in growing perfect large single-crystals of 2D materials, revealing the presence and characteristics of grain boundaries becomes an important issue for practical applications. Here, we present a method to visualize the grain structure and boundaries of 2D materials by epitaxially growing transition metal dichalcogenides (TMDCs) over them. Triangular single-crystals of molybdenum disulfide (MoS₂) epitaxially grown on the surface of graphene allowed us to determine the orientation and size of the graphene grains. Grain boundaries in the polycrystalline graphene were also visualized reflecting their higher chemical reactivity than the basal plane. The method was successfully applied to graphene field-effect transistors, revealing the actual grain structures of the graphene channels. Moreover, we demonstrate that this method can be extended to determine the grain structure of other 2D materials, such as tungsten disulfide (WS₂). Our visualization method based on van der Waals epitaxy can offer a facile and large-scale labeling technique to investigate the grain structures of various 2D materials, and it will also contribute to understand the relationship between their grain structure and physical properties.

DOI： 10.1021/acsnano.5b05879

Language：English   Publishing type：Research paper (scientific journal)  

Control of the type and density of charge carriers in graphene is essential for its implementation into various practical applications. Here, we demonstrate the gate-tunable doping effect of adsorbed piperidine on graphene. By gradually increasing the amount of adsorbed piperidine, the graphene doping level can be varied from p-to n-type, with the formation of p-n junctions for intermediate coverages. Moreover, the doping effect of the piperidine can be further tuned by the application of large negative back-gate voltages, which increase the doping level of graphene. In addition, the electronic properties of graphene are well preserved due to the noncovalent nature of the interaction between piperidine and graphene. This gate-tunable doping offers an easy, controllable, and nonintrusive method to alter the electronic structure of graphene.

DOI： 10.1021/acsnano.6b00064

Language：English   Publishing type：Research paper (scientific journal)  

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DOI： 10.1021/acs.chemmater.5b01871

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DOI： 10.1021/cm501854r

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Microreactor utilizing a vertically-aligned carbon nanotube array grown inside the channels

Language：English   Publishing type：Research paper (scientific journal)  

Competition and cooperation between lattice-oriented growth and step-templated growth on aligned carbon nanotubes on sapphire

Language：English   Publishing type：Research paper (scientific journal)  

Gas analysis of CVD process for high yield growth of carbon nanotubes over metal-supported catalysts

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1016/j.cplett.2005.04.054

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DOI： 10.1021/jp050307q

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DOI： 10.1016/j.cap.2004.06.004

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Language：English   Publishing type：Research paper (scientific journal)  

We have studied the growth of carbon nanotubes by chemical vapor deposition (CVD) on the nanoparticles of iron oxide with two different diameters, 4 and 10 nm, supported on MgO powder. Both nanoparticles catalyzed the growth of double-wall carbon nanotubes (DWNTs) together with a small amount of single-wall carbon nanotubes (SWNTs). We found that the inner- and outer-diameters of the DWNTs were modified by the initial nanoparticle size; smaller nanoparticles catalyzed the growth of the DWNTs with smaller diameters. These results suggest that the MgO support strongly influence the catalytic activity of nanoparticles by reduction of the catalytically-active size.

DOI： 10.1016/j.cplett.2004.04.110

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DOI： 10.1117/1.JATIS.10.2.026006

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DOI： 10.35848/1347-4065/acb77a

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DOI： 10.1063/5.0092558

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.11470/oubutsu.90.10_617

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DOI： 10.1016/j.carbon.2022.09.021

Other Link： https://www.sciencedirect.com/science/article/pii/S0008622322007461

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DOI： 10.1364/OME.457545

Language：Japanese   Publishing type：Research paper (scientific journal)  

DOI： 10.1380/vss.65.177

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DOI： 10.1021/acs.langmuir.1c01589

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DOI： 10.1021/acs.jpcc.0c06566

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DOI： 10.1016/j.cej.2020.127721

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DOI： 10.1021/acsomega.0c01207

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DOI： 10.1021/acsnano.0c01729

Language：Others   Publishing type：Research paper (scientific journal)  

High output voltage generation of over 5 V from liquid motion on single-layer MoS2

Language：English   Publishing type：Research paper (scientific journal)  

Water stores a large amount of clean energy in its dynamic forms. Owing to the wide availability of water and the rising demand for clean energy sources, the direct electricity generation from liquid motion by low-dimensional materials such as graphene has gained much interest. Electricity generation is induced by the motion of an electric double layer at the interface between the liquid droplet and solid surface. However, the output voltage with materials such as graphene is still limited to several hundred millivolts. In this report, we present a large-area single-layer MoS₂ film grown by chemical vapor deposition as a nanogenerator, which is capable of generating a large output voltage of more than 5 V from the motion of an aqueous NaCl droplet. Our findings indicate that the high shunt resistance of MoS₂ results in a large generated voltage. Furthermore, we demonstrate the possibility to scale up the MoS₂ nanogenerator by arranging them in series and parallel connections, which respectively increase the output voltage and current, with a three-times increase with an array of three MoS₂ nanogenerators. Our work opens the application of single-layer MoS₂ for harvesting electricity from the dynamic movement of liquid, such as the capability to harvest ocean wave energy, which is also demonstrated here.

DOI： 10.1016/j.nanoen.2019.104370

Language：English   Publishing type：Research paper (scientific journal)  

Large-area graphene films have substantial potential for use as next-generation electrodes because of their good chemical stability, high flexibility, excellent carrier mobility, and lightweight structure. However, various issues remain unsolved. In particular, high-density carrier doping within a short time by a simple method, and air stability of doped graphene films, are highly desirable. Here, we demonstrate a solution-based high-density (>10¹⁴ cm⁻²) hole doping approach that promises to push the performance limit of graphene films. The reaction of graphene films with a tetrakis(pentafluorophenyl)borate salt, containing a two-coordinate boron cation, achieves doping within an extremely short time (4 s), and the doped graphene films are air stable for at least 31 days. X-ray photoelectron spectroscopy reveals that the graphene films are covered by the chemically stable anions, resulting in an improved stability in air. Moreover, the doping reduces the transmittance by only 0.44 ± 0.23%. The simplicity of the doping process offers a viable route to the large-scale production of functional graphene electrodes.

DOI： 10.1038/s41699-019-0090-x

Language：English   Publishing type：Research paper (scientific journal)  

The moisture barrier properties of stacked graphene layers on Cu surfaces were investigated with the goal of improving the moisture barrier efficiency of single-layer graphene (SLG) for Cu metallization. SLG with large grain size were stacked on Cu surfaces coated with CVD-SLG to cover the grain-boundaries and defective areas of the underneath SLG film, which was confirmed to be oxidized by Raman spectroscopy measurements. To evaluate the humidity resistance of the graphene-coated Cu surfaces, temperature humidity storage (THS) testing was conducted under accelerated oxidation conditions (85 °C and 85% relative humidity) for 100 h. The color changes of the Cu surfaces during THS testing were observed by optical microscopy, while the oxidized Cu into Cu ₂ O and CuO was detected by X-ray photoelectron spectroscopy (XPS). The experimental results were accord with the results of first-principle simulation for the energetic barrier against water diffusion through the stacked graphene layers with different overlap. The results demonstrate the efficiency of SLG stacking approach against moisture for Cu metallization.

DOI： 10.1038/s41598-019-40534-5

Language：English   Publishing type：Research paper (scientific journal)  

The distribution of defects and dislocations in graphene layers has become a very important concern with regard to the electrical and electronic transport properties of device applications. Although several experiments have shown the influence of defects on the electrical properties of graphene, these studies were limited to measuring microscopic areas because of their long measurement times. Here, we successfully imaged various local defects in a large area of chemical vapor deposition graphene within a reasonable amount of time by using lock-in thermography (LIT). The differences in electrical resistance caused by the micrometer-scale defects, such as cracks and wrinkles, and atomic-scale domain boundaries were apparent as nonuniform Joule heating on polycrystalline and epitaxially grown graphene. The present results indicate that LIT can serve as a fast and effective method of evaluating the quality and uniformity of large graphene films for device applications.

DOI： 10.1126/sciadv.aau3407

Language：English   Publishing type：Research paper (scientific journal)  

Organic-inorganic hybrid perovskites have attracted increased interest owing to their exceptional optoelectronic properties and promising applications. Monolayers of transition metal dichalcogenides (TMDCs), such as tungsten disulfide (WS₂), are also intriguing because of their unique optoelectronic properties and their atomically thin and flexible structures. Therefore, the combination of these different types of materials is very attractive in terms of fundamental science of interface interaction, as well as for the realization of ultrathin optoelectronic devices with high performance. Here, we demonstrate the controlled synthesis of two-dimensional (2D) perovskite/WS₂ heterostructures by an all vapor-phase growth approach. This involves the chemical vapor deposition (CVD) growth of monolayer WS₂, followed by the vapor-phase selective deposition of 2D PbI₂ onto the WS₂ with the successive conversion of PbI₂ to organic-inorganic perovskite (CH₃NH₃PbI₃). Moreover, the selective growth of the perovskite on prepatterned WS₂ enables the direct synthesis of patterned heterostructures, avoiding any damage to the perovskite. The photodetectors utilizing the perovskite/WS₂ heterostructure show increased responsivities compared with isolated thin perovskite obtained by conventional solution methods. The integration of 2D perovskite with TMDCs opens a new avenue to fabricate advanced devices by combining their unique properties and overcoming current processing difficulties of perovskites.

DOI： 10.1021/acsami.9b13904

Language：English   Publishing type：Research paper (scientific journal)  

The moisture barrier properties of large-grain single-layer graphene (SLG) deposited on a Cu(111)/sapphire substrate are demonstrated by comparing with the bare Cu(111) surface under an accelerated degradation test (ADT) at 85°C and 85% relative humidity (RH) for various durations. The change in surface color and the formation of Cu oxide are investigated by optical microscopy (OM) and X-ray photoelectron spectroscopy (XPS), respectively. First-principle simulation is performed to understand the mechanisms underlying the barrier properties of SLG against O diffusion. The correlation between Cu oxide thickness and SLG quality are also analyzed by spectroscopic ellipsometry (SE) measured on a non-uniform SLG film. SLG with large grains shows high performance in preventing the Cu oxidation due to moisture during ADT.

DOI： 10.7567/JJAP.57.04FC08

Language：English   Publishing type：Research paper (scientific journal)  

A comparative study was carried out on the degradation of methyl orange (MO) by TiO₂ and Au/TiO₂ photocatalysts in neutral and acidic solutions. Au/TiO₂ photocatalysts with an Au : Ti atomic ratio of 1.5±0.1% : 98.5±0.1% were prepared by using a microwave-polyol method in the presence of P25 TiO₂. Initial degradation rates of MO by TiO₂ and Au/TiO₂ were 0.13 and 0.22 min⁻¹ at pH 7, whereas they increased to 0.96 and 3.06 min⁻¹ at pH 2, respectively. These results indicate that the MO degradation rates are enhanced by loading Au nanoparticles on TiO₂ in neutral and acidic solutions by factors of 1.7 and 3.2, respectively. Mass spectroscopic studies lead us to conclude that major reaction products are formed by demethylation and OH addition of benzenoid form of MO in neutral solutions, whereas they are produced through ring opening and carboxylation of quinonoid form of MO after scission of a center N-NH bond in acidic solutions. The relative importance of electron trapping and surface plasmon resonance (SPR) effects of Au nanoparticles is discussed for the enhancement of photocatalytic activity of Au/TiO₂.

DOI： 10.1002/slct.201702664

Language：English   Publishing type：Research paper (scientific journal)  

Recently, transition metal dichalcogenides (TMDCs) have attracted great interest due to their unique electronic and optical properties. Chemical vapor deposition (CVD) has been regarded as the most promising method for the synthesis of large-area TMDCs with high reproducibility. Having similar hexagonal crystal structures with many TMDCs, c-plane sapphire is commonly used as a growth substrate in CVD. However, few studies have been reported on the influence of the sapphire substrate on the growth behavior and physical properties of TMDCs. In this work, we demonstrate that higher strain is induced in epitaxially grown WS₂ grains via van der Waals interactions with sapphire as compared with misaligned WS₂ grains. In addition, this strain was found to enhance overlayer deposition on monolayer WS₂, while multilayer growth was not observed in non-epitaxial WS₂. Photoluminescence (PL) of the epitaxially grown WS₂ grains was reduced, reflecting the effective van der Waals interaction with sapphire. Moreover, low-temperature PL measurements revealed strong influence of the c-plane sapphire surface on the optical properties of WS₂. Density functional theory (DFT) calculation supports that the aligned WS₂ grains are more strongly bound to the sapphire surface, as compared with misaligned WS₂. Our work offers a new insight into the understanding of the influence of the substrate on the CVD-grown TMDC materials.

DOI： 10.1039/c8cp04418j

Language：English   Publishing type：Research paper (scientific journal)  

We demonstrate that dark-field (DF) optical microscopy is a powerful tool to visualize grain boundaries (GBs) and grain structure of graphene grown by chemical vapor deposition (CVD). Copper oxide nanoparticles sparsely formed along the graphene GBs by postgrowth mild oxidation allow one to determine the position and structure of the GBs by the DF microscope. As DF imaging offers a much higher sensitivity than bright-field (BF) microscopy, some GBs were observed even without the postgrowth oxidation. We found that periodic Cu steps formed below graphene can be also used to visualize the grain structure of the as-grown graphene by DF microscopy. Moreover, DF imaging is applicable to study of the gas barrier property of CVD graphene. Interestingly, the dissolved oxygen inside Cu foil enhanced oxidation of the Cu surface below graphene in spite of the fact that the graphene protects the underlying Cu from the exterior gas. Our work highlights the wide availability of DF optical microscopy in characterizing graphene and related two-dimensional materials grown on metal substrates.

DOI： 10.1021/acs.jpcc.7b10210

Language：English   Publishing type：Research paper (scientific journal)  

Decreasing the nucleation density of graphene grown on copper (Cu) foil by chemical vapor deposition (CVD) is essential for the synthesis of large-area single-crystalline graphene. Here, the behavior of the copper oxide layer and its impact on the graphene growth have been investigated. We found that a small amount of oxygen dissolves into the Cu when the oxide layer decomposes during the heating up in a non-reducing Ar environment. The remaining oxygen in the Cu foil can play an important role in decreasing the graphene nucleation density. The dissolved oxygen can withstand at high temperatures even in reducing H₂ environments without completely losing its effectiveness for maintaining a low graphene nucleation density. However, heating up in a H₂ environment significantly reduces the copper oxide layer during the very first moments of the process at low temperatures, preventing the oxygen to dissolve into the Cu and significantly increasing the nucleation density. These findings will help to improve the graphene growth on Cu catalyst by increasing the grain size while decreasing the grain density.

DOI： 10.1016/j.apsusc.2017.02.250

Language：English   Publishing type：Research paper (scientific journal)  

Graphene has been actively investigated as an electronic material owing to many excellent physical properties, such as high charge mobility and quantum Hall effect, due to the characteristics of a linear band structure and an ideal two-dimensional electron system. However, the correlations between the transport characteristics and the spin states of charge carriers or atomic vacancies in graphene have not yet been fully elucidated. Here, we show the spin states of single-layer graphene to clarify the correlations using electron spin resonance (ESR) spectroscopy as a function of accumulated charge density using transistor structures. Two different electrically induced ESR signals were observed. One is originated from a Fermi-degenerate two-dimensional electron system, demonstrating the first observation of electrically induced Pauli paramagnetism from a microscopic viewpoint, showing a clear contrast to no ESR observation of Pauli paramagnetism in carbon nanotubes (CNTs) due to a one-dimensional electron system. The other is originated from the electrically induced ambipolar spin vanishments due to atomic vacancies in graphene, showing a universal phenomenon for carbon materials including CNTs. The degenerate electron system with the ambipolar spin vanishments would contribute to high charge mobility due to the decrease in spin scatterings in graphene.

DOI： 10.1038/srep34966

Language：English   Publishing type：Research paper (scientific journal)  

We demonstrate a general process for fabricating graphene nanoelectronic devices that have next several features: free-standing, micrometer-sized monolayer graphene with high quality, arbitrarily-shaped metallic electrodes or sensors. In contrast to the normal routes, a gas etching process is used to create a deep trench in silicon for suspending the whole graphene device in a much larger area. User-designed electrodes or sensors are fabricated on the suspended graphene at the same time for realizing multiple functions. In this work, a suspended gold nanofilm sensor is designed to measure the intrinsic electrical and thermal properties of graphene on site. The sensor serves as both electrode and precise resistance thermometer at the same time. By simply changing the metallic electrode shape and electrical circuit, the free-standing graphene can be made into different devices, such as single-molecule detector or nano-resonator. In order to test the robustness of graphene device, a high electrical current is applied to heat the graphene in vacuum until it breaks. The breakdown current density is measured to be 1.86 mA/μm. More importantly, this method is not only limited to graphene, but also can be applied to any other two-dimensional materials.

DOI： 10.1016/j.sna.2016.05.002

Language：English   Publishing type：Research paper (scientific journal)  

We measured both in-plane electrical and thermal properties of the same suspended monolayer graphene using a novel T-type sensor method. At room temperature, the values are about 240 000 Ω^-1 m^-1 and 2100 W m^-1 K^-1 for the electrical and thermal conductivities, respectively. Based on the Wiedemann-Franz law, the electrons have negligible contribution to the thermal conductivity of graphene, while the in-plane LA and TA modes phonons are the dominant heat carriers. In monolayer graphene, the absence of layer-layer and layer-substrate interactions enhances the contribution of long wave-length phonons to the heat transport and increases the thermal conductivity accordingly. The reported method and experimental data of suspended monolayer graphene are useful for understanding the basic physics and designing the future graphene electronic devices.

DOI： 10.1063/1.4954677

Language：English   Publishing type：Research paper (scientific journal)  

We report the decrease in absorption caused by a near-infrared laser pulse in the visible region in monolayer graphene. This absorption decrease shows the existence of a two-step excitation process of carriers, in which one-photon absorption and Auger recombination sequentially occur. This process results from the linear dispersion nature of monolayer graphene. In addition, the monolayer graphene shows the ultrafast decay of carrier population. The observed properties are of importance for ultrafast optical switching utilizing the optical nonlinearity induced by carrier excitation.

DOI： 10.1021/acs.jpcc.6b01490

Language：English   Publishing type：Research paper (scientific journal)  

As a solid-state membrane with only one-atom thickness, nano-porous graphene has attracted intense attention in many critical applications. Here, the key challenge is to suspend a single-layer graphene (SLG) and drill nanopores with precise dimensions. Here, we report a simple and reliable route for making suspended fluorinated SLG with size-tunable nanopores. Our method consists of two steps: 1. a free-standing SLG ribbon was created between two gold pads after deep dry etching of silicon substrate by xenon difluoride. The SLG was fluorinated by 5-13%. Superior to the normal wet etching method, the dry etching process is much simpler and results in less hole-defect and edge deformation. A large area fluorinated SLG can be suspended due to the sufficient etch depth. 2. a focused ion beam was introduced to drill nanopores in graphene with an initial diameter around 20 nm. Followed by an electron beam induced carbon deposition, the diameter of nanopore was gradually decreased to sub-10 nm. By changing the deposition time, the size of nanopore can be precisely controlled. High-cost transmission electron microscope is no longer needed. Our method provides a simple and effective way for preparing free-standing fluorinated SLG ribbon suitable for single-molecule detection.

DOI： 10.1016/j.carbon.2015.12.070

Language：English   Publishing type：Research paper (scientific journal)  

The small spin-orbit interaction of carbon atoms in graphene promises a long spin diffusion length and the potential to create a spin field-effect transistor. However, for this reason, graphene was largely overlooked as a possible spin-charge conversion material. We report electric gate tuning of the spin-charge conversion voltage signal in single-layer graphene. Using spin pumping from an yttrium iron garnet ferrimagnetic insulator and ionic liquid top gate, we determined that the inverse spin Hall effect is the dominant spin-charge conversion mechanism in single-layer graphene. From the gate dependence of the electromotive force we showed the dominance of the intrinsic over Rashba spin-orbit interaction, a long-standing question in graphene research.

DOI： 10.1103/PhysRevLett.116.166102

Language：English   Publishing type：Research paper (scientific journal)  

Utilizing nanomachining technologies, it is possible to manipulate the heat transport in graphene by introducing different defects. However, due to the difficulty in suspending large-area single-layer graphene (SLG) and limited temperature sensitivity of the present probing methods, the correlation between the defects and thermal conductivity of SLG is still unclear. In this work, we developed a new method for fabricating micro-sized suspended SLG. Subsequently, a focused ion beam (FIB) was used to create nanohole defects in SLG and tune the heat transport. The thermal conductivity of the same SLG before and after FIB radiation was measured using a novel T-type sensor method on site in a dual-beam system. The nanohole defects decreased the thermal conductivity by about 42%. It was found that the smaller width and edge scrolling also had significant restriction on the thermal conductivity of SLG. Based on the calculation results through a lattice dynamics theory, the increase of edge roughness and stronger scattering on long-wavelength acoustic phonons are the main reasons for the reduction in thermal conductivity. This work provides reliable data for understanding the heat transport in a defective SLG membrane, which could help on the future design of graphene-based electrothermal devices.

DOI： 10.1038/srep21823

Language：English   Publishing type：Research paper (scientific journal)  

The effects of photoirradiation for the production of hydrogen from the decomposition of formic acid (FA) were studied using Ag₉₃Pd₇@Pd/TiO₂ (anatase (A) or P25 (P)) nanocatalysts. The catalytic activity was enhanced by a factor of 1.5-1.6 under UV and visible (vis) photoirradiation at room temperature for both TiO₂ supports. It was explained by the formation of an electron-rich Pd shell because of the migration of photogenerated electrons from the TiO₂ surface. The catalytic activity of Ag₉₃Pd₇@Pd/TiO₂ (A) was 1.7-7.3 times higher than that of Ag₉₃Pd₇@Pd/TiO₂ (P) without and under photoirradiation at 27-90 °C. The catalytic activity of Ag₉₃Pd₇@Pd/TiO₂ (A) under photoirradiation at 27 °C with 468 mmol H₂ g per catalyst per h, is the best value ever reported out of all of the heterogeneous catalysts using TiO₂ (A) as a photocatalyst at room temperature.

DOI： 10.1039/c6ta05699g

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/c5ta01434d

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.4907699

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1039/c4nr07007k

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DOI： 10.1016/j.sse.2014.07.009

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DOI： 10.1016/j.carbon.2014.07.010

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DOI： 10.1007/s11426-014-5073-3

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Experimental study on thermal characteristics of suspended platinum nanofilm sensors

Language：English   Publishing type：Research paper (scientific journal)  

Mechanical Immobilization of Hela Cells on aligned carbon nanotube array

Language：English   Publishing type：Research paper (scientific journal)  

Experimental study on thermal characteristics of suspended platinum nanofilm sensors

Language：English   Publishing type：Research paper (scientific journal)  

Nonlinear optical response and relaxation dynamics in double-walled carbon nanotubes

Language：English   Publishing type：Research paper (scientific journal)  

Synthesis of horizontally-aligned single-walled carbon nanotubes with controllable density and polarized Raman spectroscopy

Language：English   Publishing type：Research paper (scientific journal)  

Supramoleclar catalysts for the gas-phase synthesis of single-walled carbon nanotubes

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1103/PhysRevLett.95.065502

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1021/jp044200z

Language：English   Publishing type：Research paper (scientific journal)  

DOI： 10.1063/1.1921350

Language：English   Publishing type：Research paper (scientific journal)  

Language：English   Publishing type：Research paper (scientific journal)  

Physisorption of linear-chain alkane and fatty acid molecules on the outer surface of single-wall carbon nanotubes (SWNTs) have been studied by scanning tunneling microscopy (STM) measurements. These molecules are known to organize and form a self-assembled monolayer on a basal plane of graphite, showing a lamellar pattern. We have found that stearic acid molecules (C17H35COOH) also show a lamellar pattern on the SWNT surface. This suggests that stearic acid forms a self-assembled monolayer and modulates the surface charge density of SWNT. Formation of the self-assembled monolayer has been observed on the SWNTs surface less frequently than on the graphite surface. This is explained in terms of an inhomogeneous chirality distribution of the SWNTs and weak van der Waals interaction between the molecules and SWNTs.

DOI： 10.1016/j.cplett.2003.11.053

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Language：Japanese   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Responsible for pages：高品質グラフェンのCVD成長   Language：Japanese   Book type：Scholarly book

Responsible for pages：グラフェン上でのカルコゲナイド系層状物質のCVD成長   Language：Japanese   Book type：Scholarly book

Responsible for pages：CVD Growth of High-Quality Single-Layer Graphene   Language：English   Book type：Scholarly book

Responsible for pages："エレクトロニクス応用を目指したCVD成長 －ヘテロエピタキシャル触媒によるグラフェンの高品質化－"   Language：Japanese   Book type：Scholarly book

Responsible for pages：基礎編 第3章　４．大環状芳香族分子   Language：Japanese   Book type：Scholarly book

Responsible for pages：第1章1-1-1[5]　水平配向SWNT   Language：Japanese   Book type：Scholarly book

Responsible for pages：第31章　カーボンナノチューブ成長のための金属ナノ粒子の触媒パターニング   Language：Japanese   Book type：Scholarly book

Responsible for pages：第11章　仕事関数および半導体との接合デバイス, p.155-163.   Language：Japanese   Book type：Scholarly book

Carbon Nanotubes - Challenge to nanodevices - Chap. 11; Workfunction and integrated devices with semiconductors, H. Ago K. Tanaka ed.

Responsible for pages：Frontiers in Carbon Nanotubes and Beyond, Chap. 14, p.163-183   Language：English   Book type：Scholarly book

The Science and Technology of Carbon Nanotubes Chap. 14; Frontiers in Carbon Nanotubes and Beyond, H. Ago K. Tanaka, T. Yamabe, and K. Fukui ed.

Responsible for pages："CVD法によるグラフェンの合成技術"   Language：Japanese   Book type：Scholarly book

Language：Japanese   Book type：Scholarly book

Nano-Carbon Material -New material for chasing dreams- Natl. Inst. Adv. Ind. Sci. Tech. (AIST) ed.

Event date： 2023.10

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Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：新潟   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2010.10

Presentation type：Oral presentation (general)  

Venue：京都   Country：Japan  

Event date： 2010.6

Presentation type：Oral presentation (general)  

Venue：アモイ   Country：China  

Event date： 2009.9

Presentation type：Oral presentation (general)  

Venue：つくば   Country：Japan  

Event date： 2009.6

Presentation type：Oral presentation (general)  

Venue：仙台   Country：Japan  

Event date： 2008.12

Presentation type：Oral presentation (general)  

Venue：Boston   Country：United States  

Event date： 2008.9

Presentation type：Oral presentation (general)  

Venue：愛知   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Sendai   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：熊本   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Nagoya   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Shimane   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Suwon   Country：Korea, Republic of  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：つくば   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Yokohama   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Hokkaido   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Tokyo   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Korea, Republic of  

Language：English  

Venue：Hsinchu   Country：Taiwan, Province of China  

Language：Japanese   Presentation type：Symposium, workshop panel (public)  

Venue：オンライン   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：France  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：オンライン   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：新潟   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Kuala Lumpur,   Country：Malaysia  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：名古屋   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Barcelona   Country：Spain  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：京都   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：京都   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：京都   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Seoul   Country：Korea, Republic of  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Suzhou   Country：China  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：埼玉   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Perugia   Country：Italy  

Language：English   Presentation type：Oral presentation (general)  

Venue：Daejeon   Country：Korea, Republic of  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：鹿児島   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：大阪   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Kyoto   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Tokyo   Country：Japan  

Language：English   Presentation type：Oral presentation (general)  

Venue：Sendai   Country：Japan  

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：大阪   Country：Japan  

Presentation type：Oral presentation (invited, special)  

Venue：滋賀   Country：Japan  

Aligned growth of single-walled carbon annotubes and their characterization

Presentation type：Oral presentation (invited, special)  

Venue：東京   Country：Japan  

Aligned growth of single-walled carbon nanotubes programmed by single crystal surface

Venue：Texas   Country：United States  

Surface atomic arrangement-programmed growth of horizontally-aligned SWNTs on sapphire

Presentation type：Oral presentation (general)  

Venue：京都   Country：Japan  

Presentation type：Oral presentation (general)  

Venue：Boston   Country：United States  

Presentation type：Oral presentation (invited, special)  

Venue：神奈川   Country：Japan  

Event date： 2023.7

Language：English   Presentation type：Oral presentation (general)  

Venue：Osaka University   Country：Japan  

Event date： 2023.6

Language：English   Presentation type：Oral presentation (general)  

Venue：online   Country：Japan  

Event date： 2023.6

Language：English   Presentation type：Symposium, workshop panel (public)  

Venue：オンライン   Country：China  

Event date： 2023.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東北大学   Country：Japan  

Event date： 2021.11

Language：Japanese  

Venue：オンライン   Country：Japan  

Event date： 2021.9

Language：English  

Venue：online   Country：Japan  

Event date： 2021.8

Language：English  

Venue：online   Country：France  

Event date： 2021.7

Language：English  

Venue：online   Country：Japan  

Event date： 2021.6

Language：English  

Venue：online   Country：Japan  

Event date： 2016.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2016.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.4

Language：English   Presentation type：Oral presentation (general)  

Country：Italy  

Event date： 2016.3

Language：English   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.2

Language：English   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2016.2

Language：English   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2015.11

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.11

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.11

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.11

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：名古屋   Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.9

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.6 - 2015.7

Language：English   Presentation type：Oral presentation (general)  

Venue：名古屋   Country：Japan  

Event date： 2015.6 - 2015.7

Language：English   Presentation type：Oral presentation (general)  

Venue：名古屋   Country：Japan  

Event date： 2015.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北九州   Country：Japan  

Event date： 2015.6

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：北九州   Country：Japan  

Event date： 2015.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神奈川   Country：Japan  

Event date： 2015.3

Language：English   Presentation type：Oral presentation (general)  

Venue：神奈川   Country：Japan  

Event date： 2015.3

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：神奈川   Country：Japan  

Event date： 2015.2

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2015.2

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2015.2

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：東京   Country：Japan  

Event date： 2015.2

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.2

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.2

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.1

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2015.1

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2014.12

Language：English   Presentation type：Oral presentation (general)  

Venue：北海道   Country：Japan  

Event date： 2014.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2014.12

Language：Japanese   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan  

Event date： 2014.11 - 2014.12

Language：English   Presentation type：Oral presentation (general)  

Venue：ボストン   Country：United States  

Event date： 2014.11 - 2014.12

Language：English   Presentation type：Oral presentation (general)  

Venue：ボストン   Country：United States  

Event date： 2014.11

Language：English   Presentation type：Oral presentation (general)  

Venue：福岡   Country：Japan