Research on High-Efficiency, Single-Junction, Monolithic, Thin-Film Amorphous Silicon Solar Cells: Phase 2 Semiannual Subcontract Report, 1 February 1985-31 July 1985.

摘要

This report presents results of the second phase of research in high-efficiency, single-junction, monolithic, thin-film a-Si solar cells. Five glow-discharge deposition systems, including a new in-line, multichamber system, were used to grow both doped and undoped a-Si:H. Strong correlations were found between the breakdown voltage, the deposition rate, and the diffusion length for varying cathode-anode separations in a DC glow-discharge deposition mode. Tin oxide films were grown by chemical vapor deposition using either tetramethyl tine (TMT) or tin tetrachloride (TTC). The best films were grown with TMT, but those grown with TTC had a more controlled texture for light trapping and provided a better contact to the p-layer. Tests indicated that Ti/Al provides a stable, low-resistance back metal contact. Efficiencies of more than 10% were obtained with a p-i-n structure in which a thin, undoped a-Si:C:H layer is first deposited on the tin-oxide-coated glass. The stability of a-Si:H cells was improved by light doping of the i-layer, but the doping also caused a loss in initial performance. A new baseline submodule was designed and an active-area (350 cm sup 2 ) efficiency of 6.7% was obtained. An active-area (82.5 cm sup 2 ) efficiency of 6.7% was also obtained with laser scribing techniques. 7 refs., 31 figs., 7 tabs. (ERA citation 14:012772)