Quenching of persistent photocurrent in an oxide UV photodetector

Abstract

The sensitivity to weak light signals is a key parameter for UV photodetectors. However, a highly sensitive device has to suffer slow response speed (with photoconductive gain) or large noise current (with avalanche gain). In this work, a new type of photoconductive gain with controllable response speed is discovered in the Ga₂O₃ photodetector. The persistent photocurrent can be quenched by a 500 μs zero-voltage pulse. The photoconductive gain and the quenching of persistent photocurrent are respectively attributed to the forming and breaking of conductive filaments composed of oxygen vacancies. UV illumination has been demonstrated to accelerate the formation of the filament. This work provides a direction for the combination of speed-control and high sensitivity for photodiodes.