| Project/Area Number |
06650012
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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 science/Crystal engineering
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| Research Institution | YAMANASHI UNIVERSITY |
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Principal Investigator |
MATSUMOTO Takashi Yamanashi University, Dep. of Electrical Eng. and Computer Sci. Professor, 工学部, 教授 (00020503)
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| Project Period (FY) |
1994 – 1995
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| Project Status |
Completed (Fiscal Year 1995)
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| Budget Amount *help |
¥2,000,000 (Direct Cost: ¥2,000,000)
Fiscal Year 1995: ¥800,000 (Direct Cost: ¥800,000)
Fiscal Year 1994: ¥1,200,000 (Direct Cost: ¥1,200,000)
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| Keywords | Copper Gallium Diselenide / Ternary Compound / Chalcopyrite Semiconductor / Epitaxial Growth / MBE / Chloride Source |
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| Research Abstract |
A novel epitaxial growth technique of chalcopyrite semiconductors has been developed, that is chloride multi source epitaxial growth. The c-axis epitaxial layrs of CuGaSe_2 were grown on GaAS (100) substrates using copper monochloride (CuCl), metallic gallium (Ga) and selenium (Se) as source materials. Electrical properties of grown layrs were controlled both by controlling the stoichimetry of the layrs and by extrinsic doping.
Undoped layrs were of p-type conductivity, and there conductivities ranged from 10^<-2>S to 10^3S depending on Se/(CuCl+Ga) and CuCl/Ga supply ratios. High Se/(CuCl+Ga) supply ratios decreased the conductivities, because excess Se acted as compensating donors. Low CuCl/Ga supply ratios increased the conductivities, because Cu vacancies formed acceptor levels. The ionization energy of the acceptor was determined to be 180meV by analyzing temperature dependence of carrier concentrations.
Zn-doped layrs were of p-type conduction with sigma=3*10^<-2>-5*10^2S.The effects of source supply ratios, that is, Se/(CuCl+Ga) and CuCl/Ga supply ratios on the electrical conductivity were studied, and Zn was found to be on the Ga site and to make a 130meV acceptor level. The attempt to realize n-type conduction by introducing Zn atoms into the Cu sites was not successful.
Nitrogen was doped by the technique of active nitrogen doping. Shallow acceptor levels of 40-50mdv activation energies were observed in N doped samles.
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