The influence of temperature on structural and third order nonlinear properties of cadmium sulfide nanoparticle films prepared by chemical reaction method

Abstract

In this work Cadmium sulfide nanoparticles)CdS-NPs(was deposited on glass substrates using a polymerassisted chemical reaction method (CRM) and annealed at different temperatures, 300∘C, 400∘Cand 500∘C. The structural and optical characteristics of CdS-NPs films were investigated using X-ray diffraction (XRD), FTIR analysis, UV–Vis absorption spectroscopy and scanning electron microscopy (SEM). X-ray diffraction (XRD) and selected area electron diffraction studies confirmed the formation of nanocrystalline cubic phase of CdS in the films. The calculation shows that the CdS crystallized in cubic phase and formed NPs with average crystallite sizes of 17.2, 20.1 and 23.3 nm and the microstrain is about 0.034, 0.030 and 0.026 for CdS films annealed at 300∘C, 400∘C and 500∘C. The UV–Vis spectrophotometer measurements showed that the films were highly transparent value of 97 % at annealing temperature of 300∘Cand 400∘C. The direct allowed bandgaps have been determined and they lie in the range 2.49 -205 eV for CdS-NPs film annealed at temperatures of 300 ∘C–500∘C. The thermal non-linear refractive indices (n2) of the CdS-NPs are determined using open and closed aperture Z-scan techniques. The optical limiting (OL) behaviours have been studied. It was shown that the OL efficiency depended on the CdS-NPs temperature. Under laser irradiation, self-diffraction rings were seen in CdS-NPs-300∘C, CdS-NPs-400∘C and CdS-NPs-500∘C. With increased input power, each pattern is created by a rise in the number of rings and the diameter of the outermost ring. The aim of the current project studies is to investigate the linear and nonlinear optical characteristics to find fresh applications for CdS-NPs in the world of optical modulators.