Room-temperature metal-insulator transition of MBE grown VO_2 film investigated by temperature dependent resistance and transmittance

摘要

VO_2 films were grown on TiO_2 (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 VO_2. 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 VO_2 film and TiO_2 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 VO_2-based devices where RT MIT is necessary.