Texture and phase control of magnetron-sputtered VO2 thin films with an Al-doped ZnO seed layer using topotactic oxidization

Abstract

We developed a technique to produce stoichiometric VO2 films with a well-defined (010) orientation, using an Al-doped ZnO (AZO) thin film and topotactic oxidation. The AZO seed layer was prepared on a glass substrate by radio frequency magnetron sputtering (RF-MS), and then the V2O3 film was deposited on the AZO film by RF-MS. Finally, the V2O3 film was post-annealed, and underwent topotactic oxidation in air to convert the V2O3 phase to the VO2 phase. The AZO seed layer converted V2O3 to VO2 while maintaining the crystallographic orientation. Consequently, well-defined (010) orientated 200-nm-thick VO2 films with large change in electrical resistivity of 1.55 × 103 times together with large change in optical transmittance of 64.3% at wavelength of 2000 nm, before and after the transition, were successfully obtained by combination with AZO seed layer and topotactic oxidation.