Photoluminescence and Nonlinear Optical Properties of Copper Doped Zinc Sulfide Thin Film

Abstract

In this research, Un-doped zinc sulfide and copper doped thin films in concentrations of 3%, 4% and 7% were deposited on glass substrate by thermal evaporation method, followed by measuring and analyzing linear and non-linear optical properties of the prepared samples using Ultraviolet Visible spectrophotometry (UV-Vis), Photoluminescence (PL) and Z-scan device. The structural properties of the sample and quantitative analysis of data were examined using X-ray diffraction (XRD). Peaks resulted from charts showed that impurities in thin films of zinc sulfide did not led to a new phase in the samples, but relative intensity of peaks increased. Using measured data of the absorption spectrum, the absorption values and the nano-structured band gap of zinc sulfide and doped zinc sulfide with copper were calculated. The photoluminescence illustrated that with increasing concentrations of copper ions, PL intensity decreased. Non-linear optical measurements using continuous wave laser with wavelength of 532 nm for open and closed aperture showed that nonlinear absorption coefficient was positive for the zinc sulfide film and negative for zinc sulfide thin films with copper doped zinc. Furthermore, the refractive index and nonlinear absorption increase with increasing concentration.