Systematics in morphological, structural and optoelectrical properties of nanocrystalline CdS thin films grown by electrodeposition method

Abstract In this study, high-quality nanocrystalline CdS films are prepared on fluorine doped tin oxide (FTO) FTO/glass substrates by electrodeposition method. The properties of annealed CdS film are optimized for estimating required thickness and nano-sized grain morphology with better optoelectronic attributes at optimum growth voltages. Field emission SEM images indicate CdS films with compact and nanosized grains are obtained even after a long deposition time at optimized growth voltages. X-ray diffraction reveals the films are polycrystalline in nature with a hexagonal wurtzite structure. CdS layer thickness is obtained by cross-sectional SEM images and compared with estimates from weight gain measurements and Faraday equation. Thicknesses of about 70–100 nm within 75–120 s are obtained. Energy dispersive X-ray (EDX) analyses for elemental analysis indicate very pure CdS layers. UV–Vis spectroscopy is applied to calculate the band gap. The sheet resistance of the films is also measured by four-point probe method.