Conduction studies on copper indium diselenide thin films

Thin films of CuInSe2 were prepared by thermal evaporation onto well cleaned glass substrates kept at 303 K. The thicknesses of the films were measured by Tolansky (Fizeau fringes) technique. XRD results reveal that the films are polycrystalline in nature. Thin film capacitors of the type (Al-CuInSe2-Al) have been fabricated. Dielectric and ac conduction studies were performed on a stabilised sample of thickness 175 nm at various frequencies (10 kHz to 5 MHz) and temperatures (303-353 K). DC conduction studies were also carried out on a sample of thickness 230 nm. The value of dielectric constant has been evaluated as 10.8 at 5 MHz and at room temperature. From the ac conduction studies, it was confirmed that the mechanism responsible for the conduction process is electronic hopping. From the de conduction mechanism, it has been observed that the Schottky type of conduction is predominant in the high field region and the Schottky barrier height has been determined as 0.1 eV. The ac and de activation energies have also been calculated as 0.12 and 0.27 eV, respectively. (C) 1999 Elsevier Science S.A. All rights reserved.