Structural and electrical characterizations of the pulsed-laser-deposition-grown Sc2O3∕GaN heterostructure

Single-crystalline Sc2O3 was grown on GaN/sapphire template using pulsed laser deposition and the interface characteristics of the Sc2O3∕GaN heterostructure were investigated. An epitaxial relationship of [112]Sc2O3‖[213¯0]GaN and (222)Sc2O3‖(0002)GaN was revealed by x-ray diffraction and cross-sectional transmission electron microscopy. A valence band offset of 0.84eV was obtained by x-ray photoelectron spectroscopy, indicating a conduction band offset of 2.04eV across the Sc2O3∕GaN heterointerface. In addition, a low interface state density of 4×1011eV−1cm−2 was estimated from capacitance-voltage measurements. The epitaxial nature with good interface characteristics has rendered a substantially low leakage current of 1μA∕cm2 at a reverse gate bias of 30V in the Sc2O3∕GaN metal-oxide-semiconductor structures.