High-quality epitaxial or highly textured NiO thin films can be grown at temperatures of 400–750°C by low-pressure metalorganic chemical vapor deposition (MOCVD) on MgO, SrTiO3, C-cut sapphire, as well as on single crystal and highly textured Ni (200) metal substrates using Ni(dpm)2 (dpm – dipivaloylmethanate) as the volatile precursor and O2 or H2O as the oxidizer/protonolyzer. X-ray diffraction (XRD), scanning electron microscopy/energy dispersive detection (SEM/EDX), and atomic force microscopy (AFM) confirm that the O2-derived NiO films are smooth and that the quality of the epitaxy can be improved by decreasing the growth temperature and/or the precursor flow rate. However, low growth temperatures (400–500 °C) lead to rougher surfaces and carbon contamination. The H2O-derived NiO films, which can be obtained only at relatively high temperatures (650–750 °C), exhibit slightly broader ω scan full width half-maximum (FWHM) values and rougher surfaces but no carbon contamination. Using H2O as the oxidizer/protonolyzer, smooth and highly textured NiO (111) films can be grown on easily oxidized single crystal and highly textured Ni (200) metal substrates, which is impossible when O2 is the oxidizer. The textural quality of these films depends on both the quality of the metal substrates and the gaseous precursor flow rate.
Temperature dependence of the crystalline quality of AlN layer grown on sapphire substrates by metalorganic chemical vapor deposition