Nonpolar m-plane GaN-based light-emitting diodes on LiAlO2 (100) substrate

Abstract

M-plane (\( 1\bar{1}00 \)) GaN-based LED grown on LiAlO2 (100) substrate have been prepared by metal organic chemical vapor deposition. X-ray diffraction shows that FWHM for the m-plane GaN-based LED wafers on LiAlO2 (100) substrate is 0.237°. There exhibits small red shift (2 cm−1) for the E2 mode of GaN as shown in the Raman spectrum, the epitaxial GaN film was under a slight compressive stress as the value of 0.46 GPa, which indicates the as-grown epilayers on LiAlO2 (100) are almost fully relaxed. The optical band gap of m-plane GaN based LED was also investigated by measuring the absorption spectrum, which was calculated to be 3.419 eV. In addition, Excitonic absorption spectrum was observed in absorption spectra. A photoluminescence peak at approximately 440 nm is identified at room temperature. A strong and sharp electroluminescence peak observed at 480 nm is obtained at an injection current of 20 mA. The experimental results prove that high-quality nonpolar m-plane GaN-based LED could be obtained on LiAlO2 (100) substrates.