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

Abstract Efforts have been made to reduce the density of defects in corundum-structured α-Ga 2 O 3 thin films on sapphire substrates by applying quasi-graded α-(Al x Ga 1− x ) 2 O 3 buffer layers. Transmission electron microscopy images revealed that most strains were located in the α-(Al x Ga 1− x ) 2 O 3 buffer layers, and that the total density of dislocations in the α-Ga 2 O 3 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 × 10 8 and 6 × 10 8 cm −2 , respectively.