Facile growth of epitaxial vanadium monoxide on SrTiO3 via substrate oxygen scavenging

The deposition of vanadium metal on SrTiO3 results in the spontaneous scavenging of oxygen ions from SrTiO3 to oxidize vanadium to VOx, where x = 0.3–1.1, depending on the deposition temperature. At temperatures above 700 °C, an epitaxial film of the rock salt compound vanadium monoxide is formed on both SrTiO3 (111) and SrTiO3 (100) substrates. Surprisingly, oxygen scavenging and epitaxy persist for thicknesses over 800 Å with no sign of degradation. We describe the growth process and layer-by-layer characterization of the films using in situ reflection high-energy electron diffraction and x-ray photoelectron spectroscopy, as well as ex situ in-plane and out-of-plane x-ray diffraction and cross-sectional scanning transmission electron microscopy. This easy method of growing vanadium monoxide with controlled stoichiometry can provide new opportunities to study this normally hard to synthesize material known for the highly correlated nature of its electronic structure.