Growth and Characterization of M-Plane GaN Thin Films Grown on γ-LiAlO₂ (100) Substrates

M-plane GaN thin films were grown on LiAlO₂ substrates under different N/Ga flux ratios by plasma-assisted molecular beam epitaxy. An anisotropic growth of M-plane GaN was demonstrated against the N/Ga flux ratio. As the N/Ga flux ratio decreased by increasing Ga flux, the GaN surface trended to a flat morphology with stripes along [11[Formula: see text]0]. According to high-resolution X-ray diffraction analysis, Li₅GaO₄ was observed on the interface between GaN and LiAlO₂ substrate. The formation of Li₅GaO₄ would influence the surface morphology and crystal quality.