Effect of vanadium doping on the structural and optical characteristics of nano ZnCdS

Abstract

Nano Zn0.75-xCd0.25VxS (0≤x≤0.2, step 0.05) samples were formed by the molten salt solid state reaction method at low temperature. Synchrotron x-ray diffraction phase identification revealed biphasic ZnS structure for all samples, cubic zinc blende and hexagonal wurtzite. Rietveld analysis was applied to determine the effect of V-doping on the percentage of each phase and their structural and microstructural parameters. The existence of V ions in the Zn0.75Cd0.25S (ZnCdS) lattice is confirmed by Fourier-transform infrared spectroscopy (FTIR) technique. Utilizing the UV-vis diffuse reflectance spectroscopy, the effect of V-doping on the absorption, reflectance, refractive index, extinction coefficient and electric properties of ZnCdS were studied in detail. The optical bandgap (Eg) significantly decreased from 2.82 eV for zero V-doping to 2.55 eV for x=0.2. Also, the refractive index decreased sharply in the wavelength region 450-900 nm. ZnCdS sample has anomalous dispersion behavior while the doped samples have anomalous and normal dispersion features. The photoluminescence intensity and emitted colors in the UV and visible regions were affected by the amount of doping.