Epitaxial stabilization of single crystal anatase films via reactive sputter deposition

Single crystal-like TiO2 films possessing the anatase crystal structure have been realized on (001) LaAlO3 using reactive sputter deposition. The anatase polymorph could be epitaxially stabilized over a wide range of deposition temperatures and oxygen pressures. Both in-plane and out-of-plane X-ray diffraction measurements reflect a high degree of crystallinity for the deposited films. Thickness oscillations in the X-ray diffraction intensity and atomic force microscopy measurements indicate that the films are remarkably smooth, with surface morphology that is limited by that of the substrate. This result illustrates the effectiveness for epitaxy in stabilizing metastable phases, in particular for anatase, through matching of lattice spacing and nucleation chemistry