LAUSR

In this work, and experimentally propose inserting an SiO2 intermediate layer between the Ti and n-AlGaN layer to improve the electron injection efficiency. When the SiO2 intermediate layer is adopted, the SiO2 layer can share a part of the applied voltage and then weakens the surface depletion effect, which is confirmed by the capacitance–voltage measurement. Furthermore, the energy bending of the SiO2 layer pushes the affinity of Ti to be even higher than the conduction band of the Al0.60Ga0.40N layer, which then screens the Schottky barrier and favors the election injection. The influence of the thickness of the SiO2 intermediate layer is also investigated in this work. When the SiO2 layer becomes thick, the tunneling capability of the electrons will be significantly limited due to the increased tunnel region width, leading to increased forward voltage.