Structural transformation and tuning of electronic transitions by W-doping in VO2 thin films

Abstract

V1-xWxO2 (x = 0, 0.005, 0.01, 0.015, 0.02, 0.03, 0.04) thin films have been deposited on single-crystal sapphire substrates using pulsed laser deposition (PLD) technique. The PLD-grown films are pure and crystallographically oriented. The films are found to sustain their crystallinity even at higher percentages of doping. Even a minor inclusion of tungsten (W) starts the process of driving the lattice towards rutile phase, which is confirmed by structural analysis. The doping of W at V-site was confirmed by beamline experiments of X-ray photoemission spectroscopy. As observed from the resistivity curves, initially the transition temperature reduced up to 10 K per 0.5 at % of W doping at V-site, and this decrement is further amplified with an increase in doping. Thus, W doping was successfully employed to alter the structure quite systematically with a significant reduction in the phase transition temperature. © 2021 Elsevier Ltd