Effects of Substrate Temperature on Structural and Optical Properties of Spray-Pyrolyzed Cu(Ga0.3In0.7)Se-2 Thin Films on Polyimide Plastic Substrate

摘要

Chalcopyrite copper indium gallium diselenide Cu(Ga0.3In0.7)Se-2 films have been deposited on polyimide (PI) plastic substrate by chemical spray pyrolysis using different substrate temperatures in the range from 350A degrees C to 395A degrees C. The influence of substrate temperature on the structural and optical properties of the CIGS films was studied. High-resolution x-ray diffraction results revealed that the films exhibited chalcopyrite-type structure. The crystallite size of the films increased with increasing substrate temperature, as did their root-mean-square surface roughness. Optical transmission measurements by ultraviolet-visible (UV-Vis) spectrophotometer showed that the optical bandgap decreased from 1.28 eV to 1.16 eV as the substrate temperature was increased. This variation of the crystallite size and energy bandgap with substrate temperature makes such films a promising candidate for application in optoelectronic devices such as photoconductors and solar cells.