Atomic structure analysis of gallium oxide at the Al2O3/GaN interface using photoelectron holography

Abstract

The atomic structure of gallium oxide at the Al2O3/GaN interface was investigated using photoelectron holography. An amorphous Al2O3 layer was formed on a homoepitaxially grown n-type GaN surface by atomic layer deposition at 300 °C. The photoelectron holograms were measured by a display-type retarding field analyzer. From the forward-focusing peaks in the photoelectron hologram of Ga 3d, we confirmed that a layer of gallium oxide ordered structure is found at the Al2O3/GaN interface, and the Ga–O–Ga lattice constant on the c-axis was 1.2 times longer than the Ga–N–Ga distance of the GaN crystal structure.