Rectification behavior of type-Ⅱ CuGa2O4/β-Ga2O3 heterojunction diode

Abstract

Engineering heterojunction with different energy band structures is critical for designing wide bandgap devices with controllable versatility and improved performance. The CuGa2O4/β-Ga2O3 heterojunction diode is fabricated for the first time by thermal annealing. In this work, we reported a CuGa2O4/β-Ga2O3 heterojunction diode with a typical rectification characteristic. It has lower leakage current, lower turn-on voltage (1.7 V), lower specific on-resistance (3.55 Ω·cm−2), higher rectification ratio (over 106), and higher breakdown voltage (174 V) as compared to Au/β-Ga2O3 Schottky diode. TEM results show that the large lattice mismatch between CuGa2O4 and β-Ga2O3 leads to distorted regions with lots of interfacial states at the heterointerface. The band alignment type for CuGa2O4/β-Ga2O3 heterojunction is identified at Ⅱ with a 1.41 eV valence band offset (VBO) and a 0.36 eV conduction band offset (CBO), respectively. The recombination-tunneling model is the carriers transport mechanism for CuGa2O4/β-Ga2O3 heterojunction according to large ideality factor and TEM results. The type-Ⅱ CuGa2O4/β-Ga2O3 heterojunction may facilitate the design of β-Ga2O3 based electronic devices.