Processing of CuInSe2-Based Solar Cells: Characterization of Deposition Processes in Terms of Chemical Reaction Analyses. Annual Subcontract Report, 6 May 1995 - 5 May 1996

This report describes work performed by the University of Florida during Phase I of this subcontract. Researchers developed a nondestructive, contactless, dual-beam optical modulation technique for measuring the excess carrier lifetimes and surface recombination velocities in CuInGaSe2. They tested the method in both a reflectance and transmission mode and generated a model to interpret the data.Measurements on a sample in both modes gave measured lifetimes that agreed within experimental error. Researchers performed critical assessments of the Se unary and the In-Se and Cu-Se binary systems. The results of the Se assessment indicated that the dominant species are Se2 for T> 1000K, Se5 in the range 600<T<1000 K, and Se6 for T<600 K. Equilibrium evaporation fluxes were estimated usingthe assessed thermochemical properties. Researchers also established a cell fabrication infrastructure. The plasma-migration-enhanced epitaxy system was transferred from Boeing, and initial calibration runs were performed. In addition, researchers installed and demonstrated a capability for radio frequency sputtering of Mo, chemical-bath deposition, metal-organic chemical vapor deposition ofCdS, and rapid thermal processing of Mo/glass and Cu-Se/Mo/glass.