Thickness dependence of Cr-doped VO2 thin films deposition by reactive pulsed magnetron sputtering

Due to the interesting phase transition properties, Vanadium dioxide is a promising materials for smart windows. But phase transition temperature of 68° is high for this application. Doping is an useful method for transition temperature reducing in previous works. In this paper, different thickness VO₂ films were prepared by reactive pulsed magnetron sputtering, and a novel doping method was employed to reduce transition temperature. The results of XRD, Raman, transmittance spectra, and thermal hysteresis reveal that the transition temperature of un-doped samples is about 54~58°, and the increasing of phase transition amplitude and optical transmittance in visible decreasing with film thickness was observed. While for doped samples, all the transition temperatures reduced below 37°. For the thin thickness 12.5nm and 25nm, which phase transition performance deteriorated seriously. The thickness 25nm deposited for 1.5 h has the optimal performance of high optical transmittance and high IR adjustment ability.