Photocharge Transport and Recombination Measurements in Amorphous Silicon Films and Solar Cells by Photoconductive Frequency Mixing: Annual Subcontract Report, 13 May 1994 - 12 May 1995

This report describes work performed by the University of California at Los Angeles (UCLA) during Phase I of a subcontract with members of the National Renewable Energy Laboratory (NREL) Wide-Band-Gap Alloy Team and the Metastability and Mid-Band-Gap Alloy Team. Work was conducted in a number of areas. The technique of photoconductive frequency mixing was employed to separately determine themobility and lifetime in a-Si:H and a-SiC:H. The effects of deposition temperature and hydrogen dilution ratio and the transport properties of a-Si:H and a-SiC:H were investigated. Measurements of the electric field dependence of the drift mobility indicated that an empirical relationship exists between the field dependence and the stability of a-Si:H. In-air scanning photoemission measurementsof bare and a-Si:H-coated transparent conductor surfaces revealed inhomogeneities of composition or surface contaminates.