Study of microstructural, morphological and optical properties of sprayed vanadium doped ZnO nanoparticles

In this paper, transparent conducting thin films based on both undoped and vanadium (V) doped zinc oxide Zn1-xVxO (x-3, 5, 7 at.%), were studied. The thin films were prepared using a simple low cost deposition technique called spray pyrolysis (SP). The layers were deposited onto preheated glass substrates at 450 degrees C. The effect of vanadium on the microstructural, the morphological and the optical properties of ZnO material was carried out using X-ray diffractometer (XRD), micro Raman spectroscope, scanning electron microscope (SEM), energy dispersive analysis by X-ray (EDX) and UV-Vis-NIR spectrophotometer. We have demonstrated that doping with 3 at.% of V enhances the crystallinity of the films by estimating the grain size value, the dislocation density and the residual stress. Also, the SEM images have demonstrated that the vanadium concentrations do effect in the thin films morphology, from hexagonal-shaped grains to rounded crystals for higher doping concentrations. The optical analysis revealed that doping with 3 at.% of vanadium shows a remarkable enhancement in the average transmittance in the visible range 89% and in the band gap energy (3.3 eV). Moreover, the disorder inside the samples was estimated using Urbach equation. Therefore, the microstructural, the morphological and the optical results approve that doping with 3 at.% of V in ZnO lattices gives interesting results for the optical window material for solar cells application.