Fabrication of a transparent ultraviolet detector by using n-type Ga2O3 and p-type Ga-doped SnO2 core–shell nanowires

Abstract

This study investigates the feasibility of synthesizing high-density transparent Ga₂O₃/SnO₂:Ga core–shell nanowires on a sapphire substrate at 1000 °C by VLS. The doping Ga concentrations are 0.46, 1.07, 2.30 and 17.53 atomic%. The XRD spectrum and HR-TEM reveal Ga₂O₃ and SnO₂ as having monoclinic and tetragonal rutile structures, respectively. Experimental results indicate that the XRD peak shift of SnO₂ to a larger angle increases with the increasing amount of Ga doping. According to the CL spectrum, SnO₂ and Ga₂O₃ peak at approximately 528–568 nm and 422–424 nm, respectively. The maximum quantum efficiency of Ga₂O₃/SnO₂:Ga core–shell nanowires is around 0.362%. The UV light on–off current contrast ratio of Ga₂O₃/SnO₂:Ga core–shell nanowires is around 1066.7 at a bias of 5 V. Moreover, the dynamic response of Ga₂O₃/SnO₂:Ga core–shell nanowires has an on–off current contrast ratio of around 16. Furthermore, the Ga₂O₃ region functions similar to a capacitor and continues to accumulate SnO₂:Ga excited electrons under UV light exposure.