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

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.