Abstract
CuIn1-x Ga (x) Se (CIGS) powder was synthesized via the direct reaction of elemental copper, indium, gallium and selenium using ball milling. CIGS thin films were deposited onto glass substrates by using electron beam deposition at different substrate temperatures ranging from 200 a"integral to 500 a"integral. The effect of substrate temperature on the structure, surface morphology and optical properties of the films were investigated by using X-ray diffraction, energy dispersive X-ray analysis, atomic force microscopy and optical spectroscopy. Increasing the substrate temperature improved the crystallinity of the films; in addition, the (112) preferred orientation became stronger, the grain size increased from 222 to 414 and the unit cell volume increased from 350.4 (3) to 384.1 (3). The stoichiometry of the films varied with the substrate temperature. The optical properties, band gap and refractive index were reduced as the substrate temperature was increased.