Research on Defects and Transport in Amorphous-Silicon-Based Semiconductors: Final Subcontract Report, 20 February 1991 - 19 April 1994
This report describes work on three individual tasks as follows. (1) Electron and hole drift measurements in a-Si{sub 1-x}Ge{sub x}:H and a-Si{sub 1-x}C{sub x}:H p-i-n solar cells. Multijunction solar cells incorporating modified band gap a-Si:H in a triple-junction structure are generally viewed as the most promising avenue for achieving an amorphous silicon-based solar call with 15% stabilized conversion efficiency. The specific objective of this task was to document the mobilities and deep-trapping mobility-lifetime products for electrons and holes in a-Si{sub 1-x}Ge{sub x}:H and a-Si{sub 1-x}C{sub x}:H alloys materials. (2) Electroabsorption measurements and built-in potential (V{sub bi}) in solar cells. V{sub bi} in a p-i-n solar call may be limiting the open-circuit voltage (V{sub oc}) in wide-band-gap cells (E{sub g} > 1.8 eV) currently under investigation as the top cell for 15% triple junction devices. The research addressed four issues that need to be resolved before the method can yield an error less than 0.1 V for V{sub bi}. The details are presented in this report. (3) Defect relaxation and Shockley-Read kinetics in a-Si:H. Quantitative modeling of solar cells is usually based on Shockley-Read kinetics.`` An important assumption of this approach is that the rate of emission of a photocarrier trapped on a defect is independent of quasi-Fermi level location.
- 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:
- 10182625
- Report Number(s):
- NREL/TP-451-7164; ON: DE94011888; BR: WM1020000
- Resource Relation:
- Other Information: PBD: Sep 1994
- Country of Publication:
- United States
- Language:
- English
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