Structural and optical characterization of sprayed Mg and Ni co-doped CdS thin films for photovoltaic applications

Abstract

In the present work, Mg and Ni co-doped CdS thin films are grown on glass substrates at a temperature of 400 °C through spray pyrolysis. The influence of Mg-doping on structural, morphological and optical properties of CdS:Ni thin films are examined. Mg level is changed from 0 % to 7 % for CdS: Ni samples just as Ni concentration is fixed 2 % for all CdS thin films. It is observed from the X-ray diffraction spectra that all the samples exhibit hexagonal structure of CdS thin films. The scanning electron microscopy (SEM) images showed a dense surface structure composed of crystallites whose average size increase with increasing the Mg doping. The optical transmission curves demonstrate that CdS:Ni thin films exhibit a best optical transparency in the visible range for 1 % Mg content compared to other specimens. The energy of the optical band gap tends to decrease from 2.46 to 2.40 eV with increasing Mg concentration in CdS: Ni.