Characterization of defects in β-Ga2O3 single crystals

We have investigated defects in beta-type gallium oxide (beta-Ga2O3)single crystals by X-ray topography, selective etching, and transmission electron microscopy. Two types of defects, namely, dislocations and nanopipes, were found. Dislocations are screw dislocations with Burgers vector parallel to [010]. The majority of them lie on ((2) over bar 01) and (001). Nanopipes are hollow pipes of 0.1 mu m diameter and of at least 15 mu m length elongated along [010]. No strain field was found around them. From the observation results, we have discussed the formation mechanisms of these defects. (C) 2015 The Japan Society of Applied Physics