Mechanochemically Synthesized CIGS Nanocrystalline Powder for Solar Cell Application

Copper Indium Gallium Diselenide (CIGS) is a compound semiconductor material from the group of I-III-VI. The material is a solid solution of copper, indium and selenium (CIS) and copper, gallium and selenium with an empirical formula of CuIn(1 – x)GaxSe2, where 0 x 1. CIGS has an exceptionally high absorption coefficient of more than 105 cm – 1 for 1.5 eV. Solar cells prepared from absorber layers of CIGS materials have shown an efficiency higher than 20 %. CuIn(1 – x)GaxSe2 (x 0.3) nanocrystalline compound was mechanochemically synthesized by high-energy milling in a planetary ball mill. The phase identification and crystallite size of milled powders at different time intervals were carried out by X-ray diffraction (XRD). The XRD analysis indicates chalcopyrite structure and the crystallite size of about 10 nm of high-energy milled CIGS powder after two and half hours of milling. An attempt for preparing the thin film from CIGS nanocrystalline powder was carried out using the flash evaporation technique. Scanning electron microscopy (SEM) reveals uniform distribution of CIGS particles in thin film.