Structural and Optical properties of CdTe:CuThin Films by Pulsed Laser Deposition technique

Abstract

Polycrystalline cadimumtelluride : copper composite thin films were deposited on a glass substrate by pulsed laser deposition technique(PLD).Using Nd:YAG with 1064 nm wavelengthconstant energy 600 mJ, repetition rate (6) Hz and No. of pulse (150) for each sample.The pure of bulk (CdTe) and Mixture of bulk (CdTe:Cu) percentages (x=0.0, 0.3, 0.5 and 0.7)wt% were prepared. The structural, optical and morphological properties were inspected for the produced thin films.The energy band gap decreasing from 2.4 to 1.7eV with increase of Cu concentration. XRD patterns showed the domination of polycrystalline nature of cubic structure but in adding 0.5, and 0.7% Cu the nature of thin films became amorphous. AFM results demonstrated the increase of particle size from 73.66 nm to 76.67 nm at percentage of 0.5% Cu. The optical properties has been including the study of measuring the spectrum of transmittance, absorbance, Absorption coefficient (α), Optical Energy Gap (Eg), Reflectance (R), Refractive index, Extinction Coefficient, Dielectric Constant and Optical Conductivity (σ) of the wavelength range (320-1100) nm. The results have been show that the films have good transmittance for all films around 60-94% in the visible region and NIR of the spectrum that we can use them as optical windows in solar cells.