Abstract

Cu–In–Se–Te thin films have been produced by electrodeposition on molybdenum electrodes supported on glass substrates. The composition of the films is a function of the growth conditions. The best conditions for a near-stoichiometric composition are a deposition potential of −0.5 V vs. SCE and a time greater than 4000 s. After electrodeposition the samples are amorphous. However, crystallization of the films can be achieved by various thermal treatments, for example, annealing in a Te atmosphere at 550 °C for 30 minutes followed by annealing under vacuum at 400 °C for 1 h. This produces crystalline quaternary phases, as confirmed by X-ray diffraction. In order to study the optical properties of the films, some samples were grown on indium tin oxide (ITO) electrodes and annealed at 550 °C for 30 min. The observed absorption coefficients showed two regions corresponding to two energy gaps having values of E_g1 = 0.81 eV and E_fg1 = 1.28 eV. The same films exhibited photoelectrochemical responses with flatband potentials of −0.15 V. All samples exhibited p-type conduction.