Preparation of CdS semiconductor thin films by a solution growth technique

CdS semiconductor thin films have been chemically prepared from an aqueous solution containing CdSO 4, thiourea and NH 4OH. X-ray diffraction studies of the air-annealed films indicate the presence of polycrystallines with mixed cubic and hexagonal phases of CdS in the deposit. Scanning electron microscopy analysis of the deposit indicates the surface to be non-uniform and spongy. Rutherford backscattering spectroscopy (RBS) and proton-induced X-ray emission (PIXE) analysis have been carried out to estimate the Cd-to-S ratio and found to be 1.06 (RBS) and 0.905 (PIXE) respectively. The band gap has been estimated from optical absorption studies and found to be 2.47 eV. The photoactivity of the CdS films has been tested with a polysulfide electrolyte which gave an open circuit photovoltage ∼ 160 mV and a short circuit photocurrent density ∼ 720 μA cm −2 respectively under 40 mW cm −2 intensity of illumination.