Cu2O quantum dots modified α-Ga2O3 nanorod arrays as a heterojunction for improved sensitivity of self-powered photoelectrochemical detectors

Abstract

Long distance charge transfer will lead to the recombination of carriers, which seriously limits the practical application of photoelectrochemical (PEC) detector. In this work, a self-powered solar-blind photodetector based on a mixed dimensional α-Ga2O3 nanorod arrays and Cu2O quantum dots has been prepared by a simple hydrothermal method and a two-part impregnation method. Cu2O quantum dots can form type Ⅱ heterojunction with α-Ga2O3 and effectively reduce the photoinduced electron and hole recombination due to their short carrier transport distances. Just because of this, α-Ga2O3 photodetectors modified by Cu2O quantum dots present special self-power optical response at 254 nm, with optical flow densities of 13.88 μA/cm2, large responsivity of 4.57 mA/W, high detection sensitivity of 2.107 × 109 Jones and fast photoresponse time of 0.815 s/0.978 s. This kind of thought provides a simple and feasible method for the preparation of α-Ga2O3 and other semiconductor oxides based on PEC photodetectors.