Comparative microstructural studies using different methods: Effect of Cd-addition on crystallography, microstructural properties, and crystal imperfections of annealed nano-structural thin CdxZn1-xSe films

Abstract

Thermally evaporated zinc-cadmium selenide (CdxZn1-xSe) thin films with different Cd-concentration (0.0≤x≤1.0, at%) have been prepared. The deposition process of films was controlled where the vacuum was fixed at ≈10−5 Pa, the film thickness at 7500 Å, and the rate of deposition at ≈100 Å/s. These prepared films have been annealed under vacuum at 500⁰C for 2-hrs. X-ray diffraction, XRD study confirmed the crystallinity nature of annealed CdxZn1-xSe films with a face-centered cubic structure, which is transformed into a hexagonal structure with increasing the cadmium. Energy-dispersive X-ray analysis shows that there is good consistency between the detected and selected element ratios. Scherrer, Williamson-Hall, Size-Strain plot, and Halder-Wagner methods were used to examine the crystallite size and microstrain using XRD peak-broadening analysis. According to the Williamson-Hall method the crystallite size increased from 14.70 nm to 31.30 nm and microstrain decreased from 14.19×10−3 to 7.29×10−3. The Cd-addition leads to improving the film crystallinity and reducing the crystal imperfections.