Optical Properties of Sol-gel Deposited ZnS Thin Films: Spectroscopic Ellipsometry

ZnS thin films with different pH (1, 3, 5 and 7) have been deposited on glass substrates using sol-gel spin coating method. The optical study of ZnS thin films is carried out by spectroscopic ellipsometry. Measured spectra and model calculations are observed to be in good agree-ment. Changes in the transmittance, band gap, refractive index and di-electric constant are studied. These results imply that the energy gap of the ZnS films increases with pH. The changes observed in the optical properties of ZnS thin films are consistent to the material's application in optoelectronic devices.