Interface chemistry and electronic structure of GaN/ MgAl₂ O₄ revealed by angle-resolved photoemission spectroscopy

By modifying the MgAl₂ O₄ substrate surface using chemical etching and thermal passivation, high-quality GaN films have been achieved on the MgAl₂ O₄ (111) substrate via metalorganic chemical vapor deposition. The interface chemistry and electronic structure of GaN/ MgAl₂ O₄ interface have been investigated by angle-resolved photoemission spectroscopy. It has been noted that thermal passivation leads to the formation of Al₂ O₃ buffered layer, which remains thermally stable during deposition and are primarily responsible for the epitaxial growth of GaN on MgAl₂ O₄ (111) substrate.