CIGS Thin Film Solar Cells By Two-Selenizations Process Using Se Vapor
A novel process consisting of two-selenizations of magnetron sputtered metallic precursors using Se vapor and a method for Ga incorporation using a single Cu-Ga(22 at.%) alloy target without deleterious indium-gallium interaction have been developed for preparation of well-ad-herent, large, compact, well-faceted-polyhedral-grain CIGS thin films having optimum composition of Cu:In:Ga:Se in atomic percent of 24.25:22.21:4.40:49.14. Higher indium proportion in the first precursor resulted in elimination of pits in the CIGS films, which made them more suitable for preparation of solar cells with thin CdS heterojunction partner layers. Optimized selenization parameters with the maximum temperature of 550-560 C and a Se vapor incidence rate of 50-75 A/s resulted in improved morphology and enhanced gallium content of completed CIGS thin films. The best solar cell had an open-circuit voltage Voc of 451.8 mV, a short-circuit current density Jsc of 34.5 mA, a fill factor of 57.87%, a total-area efficiency of 9.02%, and a fairly constant spectral response over the entire spectral range.
Florida Solar Energy Center and Dhere, Neelkanth, "CIGS Thin Film Solar Cells By Two-Selenizations Process Using Se Vapor" (1996). FSEC Energy Research Center®. 790.