Reduction in edge dislocation density in corundum-structured α-Ga2O3 layers on sapphire substrates with quasi-graded α-(Al,Ga)2O3 buffer layers

Efforts have been made to reduce the density of defects in corundum-structured alpha-Ga2O3 thin films on sapphire substrates by applying quasi-graded alpha-(AlxGa1-x)(2)O-3 buffer layers. Transmission electron microscopy images revealed that most strains were located in the alpha-(AlxGa1-x)(2)O-3 buffer layers, and that the total density of dislocations in the alpha-Ga2O3 thin films was successfully decreased by more than one order of magnitude compared with that without buffer layers, that is, the screw and edge dislocation densities were about 3 x 10(8) and 6 x 10(8) cm(-2), respectively. (C) 2016 The Japan Society of Applied Physics