Influence of Film Thickness on the Optical Properties of Antimony Sulphide Thin Films Grown by the Solution Growth Technique

P.A. Nwofe

Abstract

In this study, the effect of film thickness on the optical properties of antimony sulphide (Sb2S3) thin films grown on soda-lime glass substrate using the solution growth technique is reported. The film thickness was varied by altering the deposition time. The deposition time was between 1h to 5h and the other deposition variables were kept constant. The results show that the film thickness increased with an increase in the deposition time, and attained a maximum thickness at the deposition time of 4h and decreased thereafter. The film thickness was obtained in the range of 35 nm to 98 nm. The optical properties of the films were investigated using a UV-spectrophotometer to determine the transmittance and absorbance versus wavelength in the range of 400 nm to 1250 nm. Analysis from the optical characterisation reveals that the optical constant; energy bandgap, extinction coefficient, and the optical density varied with the film thickness. The optical energy bandgap was direct and in the range of 2.05 eV to 2.10 eV. The extinction coefficient was in the range 0.01 ≤ 0.27 while the optical density was between 0.01 ≤ 0.34.