Synthesis and characterization of nanostructural CuS-ZnS binary compound thin films prepared by spray pyrolysis

We have investigated the effect of zinc concentration ([Zn]/(Cu] = 0-100 at%) on nanostructural, optical and electrical properties of CuS-ZnS binary thin films grown on glass substrate by the spray pyrolysis technique. X-ray diffraction analysis showed that the films were crystallized with mixed structures of CuS hexagonal and ZnS cubic structure. UV-vis optical measurements analysis showed that these binary films have a relatively high absorption coefficient (similar to 10(5) cm(-1)) in the visible spectrum with a direct band gap in the range of 2.57-2.45 eV in agreement with the corresponding room temperature PL spectra. The electrical studies showed that all these samples have a p-type conductivity and the free hole density decreases with increasing [Zn]/[Cu] molar ratio, in agreement with the reflectance spectra of the layers, originating from plasma oscillations. (C) 2012 Elsevier B.V. All rights reserved.