Inclined ZnO thin films produced by pulsed-laser deposition

ZnO thin films with a uniformly inclined structure are grown by pulsed-laser deposition on SrTiO3. The c-axis of ZnO films is inclined by an angle θ=20±0.5° and θ=42±0.5° against the surface normal of 25° miscut (100) SrTiO3 and (110) SrTiO3 single crystal substrates, respectively. The inclined structure is due to epitaxial growth of hexagonal ZnO on cubic SrTiO3 as evidenced by X-ray diffraction and high-resolution transmission electron microscopy investigations. The range of deposition parameters (substrate temperature, oxygen background pressure) to achieve epitaxial growth is determined. The inclined films are smooth with an rms surface roughness of ∼1.5 nm for layer thicknesses up to 700 nm.