Growth behavior of nonpolar GaN on the nearly lattice-matched (1 0 0) γ-LiAlO₂ substrate by chemical vapor deposition

Nonpolar gallium nitride (GaN) epitaxial film was grown on a nearly lattice-matched (1 0 0) γ-LiAlO₂ substrate by a versatile chemical vapor deposition (CVD) method. LiAlO₂ single crystal was grown by the Czochralski (Cz) method. Epi-ready LiAlO₂ single-crystal substrate with RMS roughness of 0.24-0.32 nm were used for all experiments. The dependence of growth characteristics on the growth temperatures and deposition time was investigated. The orientation of GaN film was identified as (1 0 1̄ 0) m-plane by X-ray diffraction pattern. The characterization of detailed structure of the nonpolar GaN epilayer was done by transmission electron microscopy (TEM). Optical properties examined by photoluminescence spectra exhibit a strong near-band-edge emission peak at 3.37 eV and a weak yellow band emission.