2015 Fiscal Year Research-status Report
Investigation of co-doped GaAs:NSb/AlGaAs IBSC with ideal transition energies for high efficiency Solar Cells
| Project/Area Number |
26790007
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| Research Institution | National Institute for Materials Science |
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Principal Investigator |
エルボーグ マーティン 国立研究開発法人物質・材料研究機構, 若手国際研究センター, ICYS研究員 (60724630)
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| Project Period (FY) |
2014-04-01 – 2017-03-31
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| Keywords | 太陽電池 / 量子構造 / MBE / GaNAs / エピタキシャル |
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| Outline of Annual Research Achievements |
Using dilute-N GaAs quantum structures I am working on improving the crystal quality and growth procedure of the material. I investigate the co-doping with Sb to compensate lattice strain induced by the small N atoms to achieve a low defect density. Futhermore, influence of N plasma condition and substrate temperature during growth were investigated.
Embedded in AlGaAs or GaAs I characterize GaNAs quantum wells as a model system of Intermediate Band Solar Cells for their opto-electronic and photovoltaic properties with the goal to of realizing an operational Intermediate Band Solar Cell (IBSC).
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
- In growth experiments the Sb incorporation rates under different growth conditions have been determined. Optical quality of GaNAs has been improved by Sb incorporation confirmed by PL.
- Close-to-ideal transition energies for IBSCs have been achieved by fabricating GaNAs/AlGaAs QW structures with 3% N and 30% Al.
- Deep-level transient spectroscopy experiments have been carried out to determine the activation energy GaNAs/AlGaAs QW of low N composition and GaAs/AlGaAs QWs. The opto-electronic properties of GaNAs with varying N concentration have been investigated.
- A major step of achieving a working IBSC has been achieved by realizing an open-circuit voltage beyond the level of the lowest present transition energy in deep GaNAs QW samples.
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| Strategy for Future Research Activity |
DLTS measurements of further GaNAs/AlGaAs QW samples with different N concentrations as well as different doping of the QW structure will be investigates to characterize carrier escape from the confinement.
Changing the host material to GaAs, to grow GaNAs QW embedded in GaAs is an extremely interesting band configuration where preliminary results show that there is almost no valance band offset. DLTS measurement will be performed to determine if holes can freely pass the QW region without recombination. This would be a highly advantages structure compared to usual quantum structure embedded solar cells, where a confinement of both electrons and holes leads to excessive recombination.
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| Causes of Carryover |
Using existing NIMS equipment saved research grant money. This will be used for more sophisticated measurements with powerful DLTS equipment in collaboration with Technical University Freiberg from April/May.
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| Expenditure Plan for Carryover Budget |
DLTS measurements of further GaNAs/AlGaAs QW samples with different N concentrations as well as different doping of the QW structure will be investigates to characterize carrier escape from the confinement.
Changing the host material to GaAs, to grow GaNAs QW embedded in GaAs is an extremely interesting band configuration where preliminary results show that there is almost no valance band offset. DLTS measurement will be performed to determine if holes can freely pass the QW region without recombination. This would be a highly advantages structure compared to usual quantum structure embedded solar cells, where a confinement of both electrons and holes leads to excessive recombination.
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Research Products
(4 results)
