GaN Thin Film Growth on LiGaO2 Substrate with a Multi-Domain Structure

We investigated the differences in the growth morphologies of hexagonal GaN thin films on {001}LiGaO2 substrates with a multi-domain structure. GaN thin films grown on one domain, where the etching rate was high using an aqueous solution of nitric acid (H2O:HNO3=1:1), peeled off. On the other hand, GaN thin films with good crystallinity grew epitaxially on the other domain, where the etching rate was low. These results strongly suggest that the peeling-off of GaN film from a {001}LiGaO2 substrate must be closely related to the differences in the chemical stability and/or polarity of the two domains.