Thin-Film Amorphous Silicon Alloy Research Partnership: Phase II Annual Technical Progress Report, 2 February 1996 - 1 February 1997

This report describes the research performed during Phase II of a three-phase, 3-year program. The research program is intended to expand, enhance, and accelerate knowledge and capabilities for developing high-performance, two-terminal multijunction amorphous silicon (a-Si) alloy modules. We discuss investigations on back reflectors to improve cell performance, and investigate uniformity inperformance over a 1-sq.-ft. area. We present results on component cell performance, both in the initial and in the light-degraded states, deposited over a 1-sq.-ft. area. The uniformity in deposition is investigated by studying the performance of subcells deposited over the entire area. We also present results on the performance of triple-junction cells and modules. The modules use grid-linesand encapsulants compatible with our production technology. We discuss the novel laser-processing technique that has been developed at United Solar to improve energy-conversion efficiency and reduce manufacturing costs. We discuss in detail the optimization of the processing steps, and the performance of a laser-processed, triple-junction device of 12.6 cm2 area is presented. We also presentexperimental results on investigations of module reliability.