Effect of CdS Thickness on the Optical and Structural Properties of TiO2/CdS Nanocomposite Film

Abstract

Efficient modification of energy band gap to absorb visible light in TiO2 semiconductor nanocomposites is challenging. The effect of the varying CdS thickness (50-100 nm) on the structural and optical properties of TiO2/CdS nanocomposite films (NCF) grown by electron beam deposition is reported. The surface morphology and optical behaviors are characterized via XRD, AFM and UV-Vis measurements. The lattice parameters and nanocrystallinity of TiO2/CdS NCF determined from XRD patterns are found to increase gradually with the increase of CdS thickness. The mean particles size estimated using Scherer formula and AFM micrographs lies in the range of 10.29 -59.71 nm for various CdS thickness. The increase in root mean square roughness with the increase of CdS thickness is revealed by AFM micrographs. The UV-Vis measurement shows a significant enhancement in the absorption of NCFs in the range of 340 to 500 nm due to the addition of a small portion of CdS. Interestingly, Our results suggest that the optical and structural properties of TiO2 films can significantly be improved and finely tuned by varying the thicknesses of CdS film useful for applications.