Rectifying characteristics and solar-blind photoresponse in β-Ga₂O₃/ZnO heterojunctions

Heterojunctions composed of β-Ga₂O₃ and ZnO films are fabricated on sapphire substrates by using the laser molecular beam epitaxy method. The heterojunction possesses excellent rectifying characteristics with an asymmetry ratio over 10⁵. Prominent solar-blind photoresponse effect is also observed in the formed heterojunction. The photodetector exhibits a self-powered behavior with a fast response speed (rise time and decay time are 0.035 s and 0.032 s respectively) at zero bias. The obtained high performance can be related to the built-in field driven photogenerated electron-hole separation.