Microscopic Origins of Metastable Effects in a-Si:H and Deep Defect Characterization in a-Si,Ge:H Alloys: Final Subcontract Report, 1 February 1991 - 31 January 1994
This research supported by NREL Subcontract XG-1-10063-1 over the past three years has involved, first of all, a fairly complete characterization of a two series of a-Si{sub 1-x}Ge{sub x}:H samples: a series of 9 films grown at the University of Delaware by the photo-CVD method (for 0.29 {<=} {times} {<=} 0.62) and series of 6 films grown at U.S.S.C. by the glow discharge method (for 0.20 {<=} {times} {<=} 0.50). Both these series of samples seem to represent what is close to the {open_quotes}state-of-the-art{close_quotes} in current a-Si,Ge:H alloys. The authors detailed comparison of the properties of the glow discharge material with the photo-CVD samples show remarkable similarities rather than significant differences. In particular, measurements of these samples: (1) allowed the assignment of defect energy levels from a detailed analysis of transient sub-band-gap photocapacitance and photocurrent spectra. (2) The authors found the density of deep defects to increase exponentially with the germanium content. (3) The authors found that the trapping lifetimes related {mu}{tau} products for holes decrease in direct proportion to the density of midgap defects in these samples, at least up to Ge fractions of 50at.%. (4) The authors have also made significant progress toward identifying both the optical and thermal defect transitions in the a-Si,Ge:H alloys.
- Research Organization:
- National Renewable Energy Lab. (NREL), Golden, CO (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE)
- DOE Contract Number:
- AC36-08GO28308
- OSTI ID:
- 10183684
- Report Number(s):
- NREL/TP-451-7163; ON: DE94011887; TRN: 94:008462
- Resource Relation:
- Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SILICON ALLOYS
CRYSTAL DEFECTS
GERMANIUM ALLOYS
SILICON
HYDRIDES
PROGRESS REPORT
CHEMICAL VAPOR DEPOSITION
FILMS
ENERGY LEVELS
IMPURITIES
photovoltaics
solar cells
hydrogenated amorphous silicon
defect characterization
germanium
metastability
360602
140501
STRUCTURE AND PHASE STUDIES
PHOTOVOLTAIC CONVERSION