Growth and Band Gap Control of Corundum-Structured α-(AlGa)2O3 Thin Films on Sapphire by Spray-Assisted Mist Chemical Vapor Deposition

Following the previous achievement of highly crystalline α-Ga 2 O 3 thin films on c -plane sapphire, the growth of corundum-structured α-(Al x Ga 1- x ) 2 O 3 was examined aiming at the future application of α-(Al x Ga 1- x ) 2 O 3 /Ga 2 O 3 heterostructures to power devices and other functional devices. The results show the control of x and band gap up to 0.81 and 7.8 eV, respectively, maintaining the dominant corundum structure. The transmission electron microscope observation suggested the formation of the crystallographically good interface of α-(Al x Ga 1- x ) 2 O 3 /Ga 2 O 3 without the severe generation of threading dislocation lines from the interface.