Strained interface layer contributions to the structural and electronic properties of epitaxial V₂O₃films

We report on the transport properties of epitaxial vanadium sesquioxide (V2O3) thin films with thicknesses in the range of 1 to 120 nm. Films with the thickness down to nanometer values reveal clear resistivity curves with temperature illustrating that even at these thicknesses, the films are above the percolation threshold and continuous over large distances. The results reveal that with the reducing thickness, the resistivity of the films increases sharply for thicknesses below 4 nm and the metal-insulator transition (MIT) is quenched. We attribute this increase to a strained interface layer of thickness ∼ 4 nm with in-plane lattice parameters corresponding to the Al2O3 substrate. The interface layer displays a suppressed MIT shifted to higher temperatures and has a room temperature resistivity 6 orders of magnitude higher than the thicker V2O3 films.