Large scale epitaxial graphite grown on twin free nickel(111)/spinel substrate

Abstract

Single crystal graphite is an extremely useful substrate to grow functional single crystalline films for future electronic and optoelectronic device applications. Due to weak van der Waals interaction, it allows one to grow high quality epitaxial films without the restriction of lattice matching and the films are relaxed at the interface without generating a high density of misfit induced defects even with very large lattice mismatch systems. However, the sizes of single crystalline graphite substrates are typically very small when cleaved from the natural graphite or exfoliated from the commercial highly oriented graphite. In this study we grew large scale single crystalline AB-stacking graphite films by chemical vapor deposition of graphite on wafer size, single crystalline Ni(111) films that were epitaxially grown by magnetron sputtering on spinel (MgAl₂O₄(111)) substrates. Our results show that smooth, single crystalline graphite films can be achieved at temperatures below 925 °C. Growth temperatures higher than 1000 °C promotes much rougher and thicker graphite films resulted from the inhomogeneous graphite segregation and precipitation processes in the Ni film. These large single crystalline graphite films may serve as substrates to grow functional semiconductor films for electronic and optoelectronic device applications.