▎ 摘 要
Studies were conducted on epitaxial VO2 thin films to assess to the effect of remote epitaxy on the metal-insulator transition (MIT). The epitaxial VO2 heterostructures were synthesized on both bare Al2O3 (0001) substrates and Al2O3 substrates coated with two monolayer-thick graphene. While both systems exhibit the MIT, the film grown by remote epitaxy on graphene demonstrates improved transport properties. Electrical transport measurements show that the on/off ratio is enhanced by a factor of similar to 7.5 and the switching temperature window is narrower for VO2 thin films grown on graphene. By characterizing the heterostructures with a suite of structural, chemical, and spectroscopic tools, we find that the graphene interlayer inhibits oxygen vacancy diffusion from Al2O3 (0001) during the VO2 growth, resulting in improved electrical behavior at the MIT.