Study the effect of thiourea concentration on optical and structural properties of CdS-nanocrystalline thin films prepared by CBD technique

Nano crystalline CdS thin films have been deposited on glass substrate employing chemical bath deposition technique by varying thiourea concentration in two different cadmium sources as cadmium chloride (S1) and cadmium acetate (S2). The aim of this research is to investigate the effect of thiourea concentration on optical and structural properties of the deposited CdS thin films. XRD analysis reveals that the CdS thin films fabricated by using S1 have zinc blende cubic structure and S2 have hexagonal as well as cubic structure. UV–vis studies demonstrate that as the thiourea concentration increases transmission spectra shift towards the shorter wavelength and optical band gap of CdS thin films also increases from 2.45 to 2.71 eV in S1 and 2.65–2.74 eV in S2. In absorption spectra, a blue shift in the band gap was observed which indicates the formation of CdS nanoparticles measured as 31–9.91 nm in S1 and 30–15.02 nm in S2.