Growth of Rock-Salt and Spinel Structured Oxides on α-Al2O3, c-ZrO2and MgO

Abstract

ABSTRACTPulsed-laser deposition has been used to grow thin films of the rock-salt and spinel structured oxides NiO, CoO and C03O4on single-crystal substrates of α-Al2O3, MgO and C-Z1O2. The resultant microstructures were characterized in plan-view by transmission electron microscopy and by low-voltage scanning electron microscopy. In all the depositions, the parameters could be controlled to grow predominantly single-crystal films. In the NiO/(0001)α-Al2O3and CoO/(100)c-ZrO2systems, {111}-oriented films were observed which were found to be twinned close to 60° and 90° about <111> respectively. Growth of cobalt oxide films on (100) MgO at 800°C and 15 mTorr of oxygen produced {100}-oriented domains of C03O4meeting at antiphase boundaries. These observations and other recent studies re-emphasize the role of substrate crystallography in governing the orientation relationships in the overlayer.