2012 Fiscal Year Final Research Report
Properties of 3-dimensional quantum dot superlattice and application to solar cells
| Project/Area Number |
22241035
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| Research Category |
Grant-in-Aid for Scientific Research (A)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Microdevices/Nanodevices
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| Research Institution | The University of Tokyo |
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Principal Investigator |
OKADA Yoshikata 東京大学, 先端科学技術研究センター, 教授 (40224034)
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| Co-Investigator(Kenkyū-buntansha) |
KITA Takashi 神戸大学, 大学院・工学研究科, 教授 (10221186)
AKAHANE Kouichi 情報通信研究機構, 光ネットワーク研究所, 主任研究員 (50359072)
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| Project Period (FY) |
2010 – 2012
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| Keywords | 量子ドット |
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| Research Abstract |
We have studied the epitaxial growth and characteristics of InAs/GaAsSb type-II quantum dot (QD) superlattice and used it to fabricate an intermediate band (IB) solar cell, which is expected to exhibit a high efficiency. First, we have succeeded to observe a clear photocurrent production by 2-step photoabsorption process at room temperature owing to longer carrier lifetimes in type-II QDs. This effect has resulted in an improvement of short-circuit current and efficiency in IB solar cells. Second, we have studied the carrier dynamics in QD structures by ultra-fast optical spectroscopy and clarified the fundamental carrier relaxation process in direct Si-doped QDs. Third, we have studied the optical modes of emission from QD superlattice structure and showed that TM mode starts to increase in proportion to TE mode for a structure with sub-10nm spacing between QD layers indicating a clear formation of QD superlattice miniband, which is required for IB solar cells.
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