A simple, convenient, low temperature route to grow polycrystalline copper selenide thin films

A simple, convenient, low temperature method has been developed to grow cubic Cu2−xSe (x=0.2) semiconductor, semitransparent thin films, based on the reaction of CuSO4, triethanolamine, sodium selenosulphate (Na2SeSO3) in aqueous alkaline medium at 5 °C. The films were characterised by X-ray diffraction (XRD), optical absorption, Electrical measurements and AAS. The as grown film was found to be semitransparent, uniform, well adherent, dark red, diffusely reflecting, polycrystalline in FCC (cubic) with non-stoichiometric factor (x=0.2). The film shows a double band gap at 2.2 (direct allowed) and 1.4 eV (indirect forbidden). The three-dimensional (3D) optical absorption model gave results similar to those obtained from two-dimensional (2D). TEP measurements shows p-type conduction mechanism.