Demonstration on dynamic evolution of energy band offsets based in NiOx/Ga2O3 P-N heterojunction interface under heat effect

NiOx/Ga2O3 heterostructure is widely utilized to Ga2O3 electrics devices, which can work in high power density and at severe ambient temperature. However, the heat effect on band offsets in NiOx/Ga2O3 junction has rarely been reported before, and little study on the interfacial properties is definitive. Here, a novel in-situ temperature-dependent XPS characterization technique was performed to investigate the heat effect on band offsets with the temperature from 300 K to 473 K. It indicates that the conduction band offset (ΔEc) and valence band offset (ΔEv) decreases from 2.06 to 1.56 eV, and from 2.74 to 2.24 eV, respectively. It means that the heat effect advances suppression in band bending. In addition, the NiOx/Ga2O3 pn diode was fabricated and the temperature dependence of I-V measurement was performed to verify the discovery based on XPS analysis. Furthermore, the temperature coefficient is extracted to be −4 meV·K−1, which are projected to determine the band offsets at a specific temperature. This work opens scenario to study interfacial properties and makes suggestion for designing in Ga2O3 power electronics.