Epitaxial growth of ultrathin Ni films on NiO(100) and TiO 2(110)

Abstract

Epitaxial growth of ultrathin Ni films on (1 × 1) NiO(100) and (1 × 1) TiO 2(100) has been examined using low energy electron diffraction (LEED) and Auger electron spectroscopy (AES). It is found that the epitaxial orientational relationship between Ni overlayers and NiO(100) can be described using site-coincidence growth theory. However, the growth of Ni on TiO 2(110) exhibits a complex behaviour. Two types of Ni islands are formed concurrently on TiO 2(110). The first is a hexagonal structure which is oriented parallel to the substrate, and the second a hexagonal structure whose direction of growth is inclined with reference to the substrate plane. The growth modes of ultrathin Ni films on NiO(100) and TiO 2(110) have also been examined using AES. These three-dimensional epitaxial structures of Ni overlayers can be well described by the Stranski-Krastanov growth mechanism using a quasi-isotropic growth model.