1998 Fiscal Year Final Research Report Summary
Photovoltaic Effects of Low-Dimensional Structures
| Project/Area Number |
09044187
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| Research Category |
Grant-in-Aid for international Scientific Research
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| Allocation Type | Single-year Grants |
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| Section | Joint Research |
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| Research Field |
電子デバイス・機器工学
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| Research Institution | Toyota Technological Institute |
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Principal Investigator |
YAMAGUCHI Masafumi Toyota Technological Institute, Professor, 大学院・工学研究科, 教授 (50268033)
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| Co-Investigator(Kenkyū-buntansha) |
BAMHAM Keith Imperial College, Blancket Laboratory, Professor, Blancket Laboratory, Professor
YAMAMOTO Akio Fukui University, Department of Engineering, Professor, 工学部, 教授 (90210517)
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| Project Period (FY) |
1997 – 1998
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| Keywords | Quantum Well Structure / Solar Cell / Photovoltaic Effect / Gallium Arsenide / Indium Gallium Arsenide / Indium Gallium Phosphide / Gallium Nitride / Indium Nitride |
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| Research Abstract |
Low dimensional structures such as quantum wells (QWs) have potential of high-efficiency photovoltaic energy conversion with a conversion efficiency of more than 30%. The purposes of this project are to c1arify properties of various QW structure solar cells, those of tandem structures and those of them under concentrator condition, and realize high-efficiency.
Properties of GaAs/InGaAs QW structure solar cells under concentrator conditions have been studied. The efficiency is found to increase super-linearly with light intensity. At a ratio of 10-suns, 23% has been obtained. Analytical calculation suggests that minority-carrier lifetime increases with increase in light intensity because of saturation of minority-carrier trapping to the recombination center. Concentrator operation of InGaP/GaAs tandem solar cells has also been examined. High-efficiency of 31.2% has been realized under 5-suns of AM1.5 illumination.
Properties of GaAs/InGaAs, AlGaAs/GaAs and InGaP/GaAs QW structures grown by molecular beam epitaxy have been studied. Potential of InGaP/GaAs system for high-efficiency solar cell application and thermo-photovo1taic application are suggested. Properties of new materials such as InN and GaN grown by metal organic chemical vapor deposition have also been studied. GaN nano-column structure has successfully been fonned by nitridation. Photon recycling effect has been studied for InP solar cells with Bragg reflector. Conversion efficiency is found to increase by about 3% using photon-recycling effect as results of increase in photocurrent and open-circuit voltage.
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