ECR-MBE growth of GaN on LiGaO2

Abstract

GaN thin films were grown at relatively low temperatures on multi-domain LiGaO2 substrates by electron-cyclotron-resonance plasma-excited molecular beam epitaxy (ECR-MBE). LiGaO2 is one of the most promising substrates for GaN epitaxial growth because of its small lattice mismatch of around 0.9%. The multi-domain LiGaO2 substrate has two different polarity domains in the (001) surface. Two different GaN surface morphologies depending on the surface polarities were observed by atomic force microscopy (AFM). The difference was also observed in the shift of photoluminescence (PL) spectra. Each peak corresponding to two inversion domains was shifted in parallel around 2nm. One possible explanation for the cause of the peak wavelength shift is due to the difference of the strains in GaN thin films.