【Domestic Papers】MSM UV photodetector with low dark current based on GaInO/SrTiO₃ heterojunction

      Researchers from the Jilin University and Institute of Semiconductors, Chinese Academy of Sciences have published a dissertation titled " MSM UV photodetector with low dark current based on GaInO/SrTiO₃ heterojunction " in Materials Science in Semiconductor Processing.

Abstract

      Doping and heterojunction manufacturing processes are widely employed techniques for modifying the energy band of wide band gap semiconductors. In this work, the sol-gel method was employed to introduce indium (In) into Ga₂O₃, leading to the formation of the GaInO (GIO) thin film, which was subsequently combined with SrTiO₃ (STO) to form the heterojunction. The heterojunction was utilized for the fabrication of metal-semiconductor-metal (MSM) structured ultraviolet (UV) photodetectors (PDs). The existence of a built-in electric field (E_bi) generated by the heterojunction at the contact interface of GIO and STO can diminish the density of majority carriers in dark conditions, consequently leading to a decrease in the dark current. The photo-to-dark suppression ratio of GIO/STO exceeds three orders of magnitude (1.157 × 10³), and the dark current of the composite GIO/STO MSM UVPDs (0.178 nA) is one order of magnitude lower than that of the individual GIO (4.028 nA) at 5V bias. Additionally, the E_bi may accelerate the exciton separation for photo-generated exciton, thereby accelerating the response speed. The GIO/STO device demonstrates a shorter rise time of 1.21 s and a decay time of 0.42 s. The utilization of both energy band modification methods offers promising prospects for the application of GIO/STO MSM UVPDs.

Paper Link：https://doi.org/10.1016/j.mssp.2023.107973