Room-temperature metal-insulator transition of MBE grown VO2 film investigated by temperature dependent resistance and transmittance

VO2 films were grown on TiO2 (001) substrate by a radio frequency (RF)-plasma assisted oxide molecular beam epitaxy. An excellent reversible metal-to-insulator (MIT) transition accompanied with an abrupt change in both resistivity and infrared transmittance was observed at room temperature (RT), which was much lower than the 341 K for bulk single crystal VO2. Remarkably, the MIT transition temperature (T-MIT) deduced from resistivity-temperature curve was well consistent with that obtained from the temperature dependent IR transmittance. The lowed T-MIT was supposed to be originated from the internal stress induced by the interface lattice mismatch between VO2 film and TiO2 substrate, this assumption was supported by both Raman measurement and X-ray diffraction (XRD) 2theta peak shift. This achievement will potentially open up new opportunities for advanced applications of VO2-based devices where RT MIT is necessary.