OPTICAL ANALYSIS OF SPRAY PYROLYSIS SYNTHESIZED CDS THIN FILMS FOR SOLAR CELL APPLICATIONS

Abstract: Here we report, room temperature deposition of CdS thin film on antimony doped tin oxide (ATO) substrate through spray pyrolysis technique. The optical properties of the CdS thin film are studied using UV-Vis-spectrophotometer, which operated the UV to the visible wavelength range. Analysis indicates that the absorbance of thin films decreases sharply at a critical wavelength (around 330nm to 349nm). Average absorption was found to be 17%. Optical absorption coefficient was estimated in the energy range. The recorded total reflectance spectra of deposited CdS thin films in the range of 250 nm to 800 nm, on glass substrates. Average reflection was approximately 10% for samples. The calculated values of the band gap of the films were found to be 2.88 eV (by Tauc plot) and 2.82 eV (ASF method). Also, the calculated value of urbach energy for CdS film is 510meV.

Keywords: Spray pyrolysis, CdS, optical characteristics, absorption, reflection, band gap, urbach energy etc.