Electrical, optical and structural properties of pure and gold-coated VO2 thin films on quartz substrate

In the present study, vanadium dioxide films were grown on quartz glass substrate by reactive KrF laser ablation technique using a vanadium dioxide target. The gold films of various thicknesses were then deposited on the VO2 film by sputtering technique. Films were characterized by X-ray diffraction to determine crystallography, by four-point probe to determine the electrical property and by double-beam spectrophotometry to determine optical reflection and transmission behaviour in the 200-2500 nm spectral region. The resistance per square of VO2 thin film decreases by two orders of magnitude across the metal insulator transition (MIT). The optical transmittance and reflectance exhibits, strong temperature dependence in the infrared region without a significant change in the visible region for VO2 thin films. The presence of gold layer on VO2 films significantly reduces the resistance per square, the critical temperature and percentage transmittance of the materials.