Studies on optical characteristics of CuInSe2 thin films

Abstract

CuInSe2 is considered as a striking semiconductor for second generation solar cells. An investigation of optical properties of CuInSe2 thin films is essential to evaluate its perfectibility as high efficiency solar cells. The films were fabricated by thermal co-evaporation technique. For this experiment, a shimadzu spectrophotometer of model number 1201 is used. The optical properties of these films are determined for the wavelength range 350 nm - 1100 nm. From the experiment it is evident that the reflectance and transmittance of the films are negligible in comparison to the absorption of these films. The high absorption coefficient of the order of 104/cm of the film material also supports this. The band gap of the CuInSe2 films was evaluated to be 1.1 eV. From XRD and EDAX analysis it is evident that CuInSe2 films are polycrystalline in nature having ideal stoichiometric composition.