An inverted AlGaAs/GaAs patterned-Ge tunnel junction cascade concentrator solar cell. Final subcontract report, 1 January 1991--31 August 1992
- Research Triangle Inst., Research Triangle Park, NC (United States)
This report describes work to develop inverted-grown Al{sub 0.34}Ga{sub 0.66}As/GaAs cascades. Several significant developments are reported on as follows: (1) The AM1.5 1-sun total-area efficiency of the top Al{sub 0.34}Ga{sub 0.66}As cell for the cascade was improved from 11.3% to 13.2% (NREL measurement [total-area]). (2) The ``cycled`` organometallic vapor phase epitaxy growth (OMVPE) was studied in detail utilizing a combination of characterization techniques including Hall-data, photoluminescence, and secondary ion mass spectroscopy. (3) A technique called eutectic-metal-bonding (EMB) was developed by strain-free mounting of thin GaAs-AlGaAs films (based on lattice-matched growth on Ge substrates and selective plasma etching of Ge substrates) onto Si carrier substrates. Minority-carrier lifetime in an EMB GaAs double-heterostructure was measured as high as 103 nsec, the highest lifetime report for a freestanding GaAs thin film. (4) A thin-film, inverted-grown GaAs cell with a 1-sun AM1.5 active-area efficiency of 20.3% was obtained. This cell was eutectic-metal-bonded onto Si. (5) A thin-film inverted-grown, Al{sub 0.34}Ga{sub 0.66}As/GaAs cascade with AM1.5 efficiency of 19.9% and 21% at 1-sun and 7-suns, respectively, was obtained. This represents an important milestone in the development of an AlGaAs/GaAs cascade by OMVPE utilizing a tunnel interconnect and demonstrates a proof-of-concept for the inverted-growth approach.
- Research Organization:
- National Renewable Energy Lab., Golden, CO (United States); Research Triangle Inst., Research Triangle Park, NC (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC02-83CH10093
- OSTI ID:
- 10129182
- Report Number(s):
- NREL/TP--411-5289; ON: DE93000073
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
140501
36 MATERIALS SCIENCE
360601
BONDING
CARRIER LIFETIME
CHARGE CARRIERS
EPITAXY
FABRICATION
GALLIUM ARSENIDE SOLAR CELLS
GALLIUM ARSENIDES
PHOTOVOLTAIC CONVERSION
PREPARATION AND MANUFACTURE
PROGRESS REPORT
SEMICONDUCTOR JUNCTIONS
SILICON
SOLAR CONCENTRATORS
SUBSTRATES
THIN FILMS