A Study on Low Cost-Highly Transparent and Conductive Molybdenum Doped Zinc Oxide Thin Films Deposited by Spray Pyrolysis Technique

摘要

Pure zinc oxide (ZnO) and Molybdenum doped zinc oxide (Mo:ZnO) thin films were deposited at 673K on micro slide glass substrates using spray pyrolysis technique. Deposited thin films are characterized by X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and UV-Visible Spectroscopy techniques. X-ray diffraction analysis of the ZnO films confirm the formation of hexagonal wurtzite crystal system and the preferred growth orientation is along (002) plane for pure and Mo doped (0.25 wt.%, 0.75 wt.% and 1 wt.%) ZnO films. For the 0.5 wt.% Mo:ZnO thin film, the (101) peak becomes prominent. The XRD intensity of the (002) peak decreases with increasing Mo doping concentration for 0.25 wt.% and 0.5wt.% then the intensity of (002) plane increases for 0.75 wt.% and 1 wt.% of Mo doping. Lattice parameter, dislocation density and strain were evaluated for the pure and Mo:ZnO thin films. Scanning Electron microscope images show nearly uniform distribution of grains on the surface of the pure and molybdenum doped zinc oxide films (Figure 1). Atomic force microscopy results show that the root mean square roughness decreases with increasing Mo concentration for the film. An average visible transmittance (AVT) of about 88% is recorded in the visible range of 400-800 nm wavelengths. Slight increase in the bandgap of ZnO is observed with increasing Mo.