Al 3+-doped vanadium dioxide thin films deposited by PLD

Abstract

Thin films of vanadium dioxide (VO 2) and Al 3+-doped VO 2 were deposited on silicon and glass substrates using pulsed laser deposition (PLD). Optimized processing conditions were determined for depositing pure VO 2 with monoclinic phase by laser ablation of a V 2O 5 target. Al 3+-doping levels in the VO 2 films were varied by altering the relative laser ablation time on the Al 2O 3 and V 2O 5 targets. The change in electrical conductivity with temperature in the semiconductor to metallic phase transition was measured for pure VO 2 and Al 3+-doped VO 2 films. Doping the VO 2 films with Al 3+ lowered the transition temperature directly on increasing the Al 3+ content from 67 °C for the pure VO 2 films to 40 °C at 10% Al 3+. The magnitude of the resistance change from semiconductor to metallic states also decreased with increase in Al 3+ doping. The results imply that Al 3+-doped VO 2 films could be a good candidate for energy-efficient “smart window” coatings used for architecture applications.