Structural, compositional and optical properties of gallium selenide thin films doped with cadmium

Polycrystalline cadmium doped gallium selenide thin films were obtained by the thermal co-evaporation of GaSe crystals and Cd grains onto glass substrates. The structural, compositional and optical properties of these films have been investigated by means of X-ray diffraction, energy dispersive X-ray analysis and UV-visible spectroscopy techniques, respectively. Particularly, the elemental analysis, the crystalline nature, the energy band gap, the refractive index, the dispersion energy and static dielectric constant have been identified. The absorption coefficient spectral analysis in the sharp absorption region revealed a direct forbidden energy band gap of 1.22 eV. The cadmium doping has caused a significant decrease in the values of the energy band gap and in all the dispersive optical parameters, as well. (C) 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinbeim.