High performance of self-powered Ga2O3:Si/p-GaN heterojunction UV photodetectors

Abstract

High performance ultraviolet (UV) photodetectors have garnered much interest for their wide range of potential in uses. On the basis of this, a self-powered UV photodetectors (PDs) based on β-Ga2O3:Si/p-GaN heterojunctions were fabricated by pulsed laser deposition (PLD) system equipped with a neodymium-doped yttrium aluminum garnet (Nd:YAG) laser at wavelength center of 266 nm. Then, the Ga2O3 (99.9 %) doped with 0.1 wt% Si was used as source to deposit Ga2O3:Si thin films on the p-GaN layer, which were deposited on c-sapphire substrates by sputtering technique. The high quality of β-Ga2O3:Si thin films are formed by well controlling the oxygen pressure during deposition, which significantly enhances the device performance. In the self-powered mode with the bias voltage of 0V, the photodetectors fabricated under oxygen pressure of 5 mTorr with low dark current of 0.6 nA, high photoresponsivity and detectivity of 2.44 × 10−2 A/W and 2.45x1011 cmHz1/2W, respectively. This study represents one of the initial self-powered UV photodetectors with unique properties, which greatly enhances the progress of multifunctional UV photodetectors.