Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
鈴木 秀俊*; 仲田 侑加*; 高橋 正光; 池田 和磨*; 大下 祥雄*; 諸原 理*; 外賀 寛崇*; 森安 嘉貴*
AIP Advances (Internet), 6(3), p.035303_1 - 035303_6, 2016/03
被引用回数:4 パーセンタイル:19.68(Nanoscience & Nanotechnology)The formation and evolution of rotational twin (TW) domains introduced by a stacking fault during molecular-beam epitaxial growth of GaAs on Si (111) substrates were studied by in situ X-ray diffraction. To modify the volume ratio of TW to total GaAs domains, GaAs was deposited under high and low group V/group III (V/III) flux ratios. For low V/III, there was less nucleation of TW than normal growth (NG) domains, although the NG and TW growth rates were similar. For high V/III, the NG and TW growth rates varied until a few GaAs monolayers were deposited; the mean TW domain size was smaller for all film thicknesses.
西 俊明*; 佐々木 拓生; 池田 和磨*; 鈴木 秀俊*; 高橋 正光; 下村 憲一*; 小島 信晃*; 大下 祥雄*; 山口 真史*
AIP Conference Proceedings 1556, p.14 - 17, 2013/09
被引用回数:0 パーセンタイル:0.01(Energy & Fuels)X-ray reciprocal space mapping during InGaAs/GaAs(001) MBE growth is performed to investigate effects of substrate misorientations on crystallographic tilting. It was found that evolution of the crystallographic tilt for the InGaAs films is strongly dependent on both layer structures and substrate misorientations. We discuss these observations in terms of an asymmetric distribution of dislocations.
高橋 正光; 仲田 侑加*; 鈴木 秀俊*; 池田 和磨*; 神津 美和; Hu, W.; 大下 祥雄*
Journal of Crystal Growth, 378, p.34 - 36, 2013/09
被引用回数:5 パーセンタイル:42.45(Crystallography)Epitaxial growth of III-V semiconductors on silicon substrates is a longstanding issue in semiconductor technology including optoelectronics, high-mobility devices and solar cells. In addition to a lattice mismatch of 4%, formation of antiphase domain boundaries makes the growth of GaAs/Si(001) more complicated than that of congeneric combinations, such as Ge/Si(001) and InGaAs/GaAs(001). In the present study, defects in GaAs/Si(001) epitaxial films are investigated by three-dimensional X-ray reciprocal-space mapping technique, which we have successfully applied for InGaAs/GaAs(001) growth. Experiments were carried out at a synchrotron beamline 11XU at SPring-8 using a molecular-beam epitaxy chamber integrated with a multi-axis X-ray diffractometer. Streaky scattering extending from the GaAs 022 peak in the directions was observed, indicating development of plane defects, such as facets and stacking faults.
佐々木 拓生*; 鈴木 秀俊*; 稲垣 充*; 池田 和磨*; 下村 憲一*; 高橋 正光; 神津 美和*; Hu, W.; 神谷 格*; 大下 祥雄*; et al.
IEEE Journal of Photovoltaics, 2(1), p.35 - 40, 2012/01
被引用回数:5 パーセンタイル:22.41(Energy & Fuels)Compositionally step-graded InGaAs/GaAs(001) buffers with overshooting (OS) layers were evaluated by several characterization techniques for higher efficiency metamorphic III-V multijunction solar cells. By high-resolution X-ray diffraction, we found that fully relaxed or tensile strained top layers can be obtained by choosing appropriate OS layer thickness. Moreover, from real-time structural analysis using X-ray reciprocal space mapping ( RSM), it was proved that the top layer is almost strained to the OS layers, and it is independent of the thicknesses of the OS layers. Dislocations in the vicinity of the OS layers were observed by transmission electron microscopy, and the validity of results of RSM was confirmed from the viewpoint of misfit dislocation behavior. Finally, by photoluminescence measurements, we showed that tensile strained top layers may be suitable for the improvement of minority-carrier lifetime.
仲田 侑加*; 鈴木 秀俊*; 池田 和磨*; Hu, W.; 神津 美和; 高橋 正光; 大下 祥雄*
no journal, ,
Si上のGaAsの成長には、安価で高効率な太陽電池の実現や光電子集積回路の実現が期待されている。しかし、Si上のGaAsの成長は成長初期から島状成長し、格子不整合や逆位相境界などにより、結晶欠陥も多い。デバイス応用が可能な単結晶膜を実現するためには、成長メカニズムの理解が必要である。本研究では、Si(001)上のGaAs層の成長メカニズムについて、三次元X線逆格子マッピングを用いて調べた。島状成長が進行している成長初期において、平均結晶粒径は成長時間の1/2乗に比例している。島の成長過程は(1)原子の表面拡散と(2)原子の島への取り込みに分けられる。この成長で見られたの依存性は、表面拡散が十分に速く、島への取り込みで成長速度が律速されていることを示している。
高橋 正光; 仲田 侑加*; 鈴木 秀俊*; 池田 和磨*; Hu, W.; 神津 美和; 大下 祥雄*
no journal, ,
Epitaxial growth of III-V semiconductors on silicon substrates is a longstanding issue in semiconductor technology. In the present work, we have employed in situ synchrotron X-ray diffraction to investigate the Volmer-Weber growth of GaAs/Si. From the three-dimensional reciprocal space mappings, structural information, such as strains, crystalline domain size and defects, was obtained during growth. The time evolution of the island size was compared with the prediction from the general nucleation theory. From the power-law exponents, it was concluded that growth processes of GaAs on Si(001) and Si(111) are limited by interface transfer and surface diffusion, respectively.