1993 Fiscal Year Final Research Report Summary
Electronic States of Negative Electron Affinity GaAs Photocathode Surface Studied with Scanning Tunneling Microscopy
| Project/Area Number |
04650014
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Applied materials
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| Research Institution | Research Institute of Electronics, Shizuoka University |
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Principal Investigator |
HAGINO Minoru Research Institute of Electronics, Shizuoka University, Professor, 電子工学研究所, 教授 (90022128)
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| Co-Investigator(Kenkyū-buntansha) |
NOMURA Takashi Research Institute of Electronics, Shizuoka University, Research Associate, 電子工学研究所, 助手 (90172816)
ISHIKAWA Kenji Research Institute of Electronics, Shizuoka University, Associate Professor, 電子工学研究所, 助教授 (50022140)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Photocathode / Negative Electron Affinity / Scanning Tunneling Microscopy / GaAs / Sulfide Treastment / Residual Gas Adsorption / Molecular Beam Epitaxy / Hetero-epitaxy |
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| Research Abstract |
The purpose of this research is to clarify the mechanism of negative electron affinity (NEA). A well defined, clean GaAs(001) surface has to be prepared to study the activation process of NEA.Therefore, we have constructed the scanning tunneling microscope (STM) which operates in ultra-high vacuum environment and mounts the same sample holder used during the MBE growth. The growth process of GaAs thin film onto an optically transparent substrate, which is essential to apply the NEA photocathode to the image intensifier, is studied by the STM.The degradation process of the NEA photocathode due to the adsorption of residual gases is studied by the temperature programd desorption spectrum (TDS). We showed the degradation is caused by the variation of Cesium/Oxide ratio in the activation layr. The sulfide treatment is also applied to the preparation of GaAs surface to achieve reproducible NEA activation. The desorption process of sulfides from GaAs surface is studied by TDS.
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