| Project/Area Number |
14350399
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Metal making engineering
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| Research Institution | KYOTO UNIVERSITY |
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Principal Investigator |
HIRATO Tetsuji KYOTO UNIVERSITY, Dept.Materials Science & Engineering, Associate Professor, 工学研究科, 助教授 (70208833)
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| Co-Investigator(Kenkyū-buntansha) |
AWAKURA Yasuhiro KYOTO UNIVERSITY, Dept.Materials Science & Engineering, Professor, 工学研究科, 教授 (70109015)
MATSUBARA Eiichiro TOHOKU UNIVERSITY, Institute for Materials Research, Professor, 金属材料研究所, 教授 (90173864)
MURASE Kuniaki KYOTO UNIVERSITY, Dept.Materials Science & Engineering, Associate Professor, 工学研究科, 助教授 (30283633)
SAGA Tatsuo SARP COOP, SOLAR SYSTEM DIVISION, DIRECTOR, ソーラーシステム事業部・第一事業部, 部長
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥15,500,000 (Direct Cost: ¥15,500,000)
Fiscal Year 2004: ¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2003: ¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2002: ¥8,400,000 (Direct Cost: ¥8,400,000)
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| Keywords | Cadmium Telluride / Cadmium Sulfide / Compound Semiconductor / Solar Cell / Electrodeposition / Chemical Bath Deposition / Transparent Electroconductive Substrate / Transmission Electron Microscope / 透明電導性基板 |
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| Research Abstract |
To develop a new soft process for CdTe thin layer solar cell, photo-assisted electrodeposition of CdTe from ammoniacal basic electrolytes was investigated. The electrical properties of polycrystalline CdTe layers electrodeposited were examined by resistivity and Hall effect measurement, As-deposited CdTe layers were found to be p-type with resistivity of 10^7-10^9Ω cm, carrier density of 10^9-10^<11> cm^<-3>, and mobility ca. 1 cm^2 V^<-1> s^<-1>. This high resistivity of CdTe layer from basic baths probably leads to low-efficiency solar cells. The microstructures of CdTe layers electrodeposited from basic electrolytes were investigated by transmission electron microscopy and compared with those from a conventional acidic sulfate electrolyte. As^- deposited CdTe layers from a basic electrolyte were composed of randomly oriented crystallites with a grain size of ca.10 nm, while those from an acidic electrolyte consisted of defective columnar grains with a <111> preferred growth orientation. Each of the columnar has a diameter of of ca.150 nm. The small grain size of the polycrystalline CdTe deposits from the basic electrolyte suggests that nucleation of new grains occurs frequently during electrodeposition. By annealing at 573 K for 1 h in an Ar atmosphere, CdTe grains from the basic electrolyte grew by about a factor of four, but at the same time, nano-voids were formed at the grain boundaries. In contrast, CdTe grains from the acidic electrolyte did not grow by annealing the same conditions. Since a large grain size is desirable for CdTe layers to be used in high-efficiency solar cells, it is important to control the nucleation of new grains during electrodeposition and the grain growth of CdTe deposits by annealing.
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