Study of the physical properties of CdTe (200): synthesized nanoparticles and grown thin films

In this work, cadmium telluride nanoparticles (CdTe NPs) were synthesized by the sonochemical method; then thin films with thicknesses about 100 nm were deposited on glass substrates using the thermal evaporation technique at substrate temperature of 200 °C and vacuum pressure of 2×10-5 mbar. The Sonochemical method is one of the best methods for synthesizing nanomaterials with very small particle sizes. After synthesis and deposition, the prepared films were subjected to x-ray diffraction (XRD), ultravioletvisible (UV-Vis) spectroscopy, and scanning electron microscopy (SEM) to study the structure, optical properties, and morphology of the films. XRD patterns indicated that the grown films were polycrystalline with a cubic structure on the preferred orientation (200). The size of the synthesized nanoparticles and crystallite size of the thin film grown on glass in the preferred orientation (200) were 16 nm and 10.65 nm, respectively. Light absorbance spectra of nanoparticles and the thin film obtained by UV-Vis spectroscopy at the wavelength range 600-1600 nm showed the increase of light absorption after deposition. The optical energy band gap was also increased from 1.48 eV for nanoparticles to 1.51 eV for the deposited films. Further the SEM images taken on the scale of 500 nm from nanoparticles and thin films showed homogeneity and uniformity of both of them