Epitaxial relationship of NiO on ( 1̅ 02) β-Ga2O3

Abstract

Abstract We investigated the epitaxial relationship of an electron-beam-evaporated NiO film on a custom-ordered ( 1 ¯ 02) β-Ga2O3 substrate with a surface orientation rotated by 13.8° around [010] axis relative to the commonly-used (001) substrate. X-Ray diffraction and transmission electron microscopy measurements confirmed that the film was monocrystalline with out-of-plane and in-plane alignments of (110)NiO||( 1 ¯ 02)β-Ga2O3 and 1 ¯ 10 NiO||[010]β-Ga2O3, respectively, indicating that the film grew on the substrate while maintaining the orientation of the cubic-close-packed (ccp) oxygen sublattice across the interface. The use of the low-index (110) epitaxial plane within the ccp lattice may be preferred for pn-heterojunctions over the higher-index (331) plane on the (001) β-Ga2O3 substrate.