Structural and optical properties of nearly stress-free m-plane ZnO film on (1 0 0) γ-LiAlO2 with a GaN buffer layer by metal-organic chemical vapor deposition

image m-plane ZnO film was epitaxially deposited on (1 0 0) γ-LiAlO2 by metal-organic chemical vapor deposition at 600 °C with a GaN buffer layer. The epitaxial relationships between ZnO and GaN, GaN and (1 0 0) γ-LiAlO2 were determined by X-ray diffraction Φ-scans. There exhibits very small decrease for the E2 mode shift (0.3 cm−1) of ZnO in the Raman spectrum, which indicates the epitaxial ZnO film was under a slight tensile stress (5.77 × 107 Pa). Unlike the highly strained a-plane ZnO, temperature dependent photoluminescence spectra show that the free A exiton emission was observed with the temperature ≤138 K.