Studies on growth and characterization of CdS sub(1-x)Se sub(x) (0.0 <= x <= 1.0) alloy thin films by spray pyrolysis

The n-CdS sub(1-x)Se sub(x) thin films of variable composition have been deposited on amorphous glass and FTO-coated glass substrate by simple and cost effective spray pyrolysis technique. The various deposition parameters have been optimized by using photoelectrochemical technique. The structural, surface morphological, compositional, optical and electrical properties have been studied. The X-ray diffraction studies indicated that all the films are polycrystalline in nature with hexagonal structure irrespective of the composition. The lattice parameters 'a' and 'c' vary from 4.1034 to 4.2615 Aa and 6.6664 to 6.9243 Aa respectively with change in composition parameter from x = 0.0 to x = 1.0. Polycrystalline texture with nearly smooth surface and clearly defined grains has been observed for all samples from scanning electron microscopy (SEM). EDAX studies confirmed that CdS sub(1-x)Se sub(x) films have approximately same stoichiometry both initially and finally. The absorption coefficient ' alpha ' is of the order of 10 super(4) cm super(-1). The optical absorption studies reveal that direct allowed transition with band gap energy between 2.44 and 1.74 eV. It is found that resistivity of the films decreased with increase in 'x' up to 0.8 and further it increases for x = 1.0. Semiconducting behavior has been observed from resistivity measurements.