Photoelectrochemical characterization of the Cu(In,Ga)S2 thin film prepared by evaporation

Cu(In,Ga)S2 chalcopyrite thin films have been characterized in order to determine the band edges potential position for photoelectrolysis water splitting. These values are correlated with the atomic composition of the samples. The characterization includes structural and atomic composition of the films. Sputtering/Sulphurization technique was used to prepare the films using different types of Cu-Ga and In targets. According to the capacitance measurements all of the films tested were p-type and the photoresponse technique shows that the band-gap values are between 1.38 and 1.74 eV. We distinguish three type of samples, low, medium and high content of Ga in the films, and the band edges potential position values depend on the amount of Ga in the films and also these values shift more positive when the pH of solution increases.