20% (AM1.5) efficiency GaAs solar cells on sub-mm grain-size poly-Ge and its transition to low-cost substrates
- Research Triangle Inst., Research Triangle Park, NC (United States)
- National Renewable Energy Lab., Golden, CO (United States)
Some of the key material and device issues related to the development of GaAs solar cells on poly-Ge substrates, including the dark-current reduction mechanism with an undoped spacer at the p{sup +}-n depletion layer, are discussed. Device-structure optimization studies that have led the authors to achieve an AM1.5 efficiency of {approximately}20% for a 4-cm{sup 2}-area GaAs cell on sub-mm grain-size poly-Ge and an efficiency of {approximately}21% for a 0.25-cm{sup 2}-area cell are presented. This successful demonstration of high-efficiency GaAs cells on sub-mm grain-size poly-Ge substrates have motivated us to consider the development of high-quality GaAs materials on significantly lower-cost substrates such as glass and moly foils. To date, the authors have achieved a best minority-carrier lifetime of 0.41 nsec in an n-GaAs thin-film on moly. The role of Group-VI dopant in the possible passivation of grain-boundaries in poly-GaAs is discussed. Development of PV-quality GaAs material, with minority-carrier lifetime of 1 to 2 nsec, on los-cost moly foils can significantly impact both the terrestrial and the space PV applications.
- Sponsoring Organization:
- National Renewable Energy Lab., Golden, CO (United States)
- OSTI ID:
- 304380
- Report Number(s):
- CONF-970953-; TRN: IM9905%%72
- Resource Relation:
- Conference: 26. IEEE photovoltaic specialists conference, Anaheim, CA (United States), 29 Sep - 3 Oct 1997; Other Information: PBD: 1997; Related Information: Is Part Of Conference record of the twenty sixth IEEE photovoltaic specialists conference -- 1997; PB: 1477 p.
- Country of Publication:
- United States
- Language:
- English
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