Effects of Sulfurization Temperature on Cu(In, Ga)S2 Thin Film Solar Cell Performance by Rapid Thermal Process

Cu(In, Ga)S2 (CIGS) absorbers were prepared using two-step process. Cu-In-Ga precursors were deposited by sputtering method and then were sulfurized by rapid thermal process based on H2S gas. Sulfurization temperature was changed from 470 degrees C to 510 degrees C. As the processing temperature increased, larger grains and denser absorbers were observed. The polycrystalline chalcopyrite structure of CuInGaS2 was shown in all samples, and their XRD peak was dominantly observed at (112) direction. CIGS thin film solar cells were fabricated with wide-bandgap absorbers obtained by varying sulfurization temperature. The best efficiency was shown with the processing temperature of 490 degrees C and 8.93% with 1.507 eV of wide optical bandgap.