AFM, micro-PL, and PV analyses of CuIn/sub 1-x/Ga/sub x/S/sub 2/ thin films solar cells on stainless steel foil

A dual-chamber, large-area magnetron-sputtering unit was fabricated. CuIn/sub 1-x/Ga/sub x/S/sub 2/ (CIGS2) thin films were prepared by sulfurization of DC magnetron-sputtered CuGa/In precursor on stainless steel foil substrates in Ar:H/sub 2/S(4%) mixture at 475/spl deg/C. CIGS2 thin films grew with chalcopyrite CuIn/sub 0.7/Ga/sub 0.3/S/sub 2/ phase with a = 5.67 /spl Aring/ and c = 11.34 /spl Aring/ and preferred {112} orientation. Inhomogeneous broadening, and variation of peak position and amplitude of microPL signal were probably caused by rough morphology and variation in the defect chemistry. Best efficiencies of CIGS2 solar cell on SS flexible foil measured at NREL and NASA GRC were 10.4% (AM 1.5) and 8.84% AM 0 respectively.