Influence of Rapid Thermal Annealing and Substrate Terrace Width on Self-Organizing Formation of Periodic Straight Nanogroove Array on NiO(111) Epitaxial Thin Film

Abstract

Room-temperature-grown NiO(111) epitaxial thin films on atomically stepped sapphire (0001) substrates by pulsed laser deposition have straight atomic steps. For a terrace width of about 50 nm, a periodic straight nanogroove array with a depth of about 6 nm was formed over the film surface after rapid thermal annealing. When using a substrate with a terrace width of about 250 nm, it is observed that two types of 180°-rotated triangular crystalline domain are alternately grown on each film terrace divided by the nanogrooves.