Abstract
Photo-conducting CdS films were coated on glass at 450 °C using cadmium chloride and thiourea as Cd and S sources, respectively, with different concentrations. The sprayed CdS films are crystallized in the hexagonal structure and orienting along (0 0 2) plane with good adherence. All the films have high optical absorption in the visible region showing optical bandgap values in the range of 2.39–2.43 eV. The variation of precursor alters the surface morphology of the films. The formed grains are uniformly spread over the substrate and highly agglomerated at 0.15 M concentration. Band to band emission and defect-related emission are reported using photoluminescence (PL) measurements. The CdS device shows relatively high photosensitivity of 0.4 A/W, detectivity of 8.46 × 10
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Jones, external quantum efficiency (EQE of 140%) with a rise time about 0.2 s and decay time about 0.3 s. These results propose that the CdS thin films are potential candidates for the visible photo-detector applications prepared using an easy and low-cost fabrication method.