Study of Nonthermal-Equilibrium Carrier Recombination and Transport in β–Ga₂O₃Metal–Semiconductor–Metal Deep-Ultraviolet Photodetectors

Abstract

Ultrawide bandgap semiconductor gallium oxide (Ga2O3) demonstrates a considerable advantage in detecting deep-ultraviolet (DUV) light signals in extreme environments. Relevant studies have shown that the Ga2O3 DUV photodetector (PD) is a promising candidate for high-temperature applications; however, its temperature-influenced photodetection performance has yet to be investigated. In this work, a Ga2O3 metal–semiconductor–metal (MSM) DUV PD was fabricated, and its temperature-dependent photodetection performance was studied. Decent detection metrics, including a photo-to-dark current ratio (PDCR) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1.1\times 10^{{6}}$ </tex-math></inline-formula> , a responsivity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}$ </tex-math></inline-formula> ) of 45.83 mA/W, a specific detectivity ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${D}^{\ast }$ </tex-math></inline-formula> ) of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.4\times 10^{{13}}$ </tex-math></inline-formula> Jones, and an external quantum efficiency (EQE) of 22.4%, were achieved but decreased with increasing temperature. The increased operation temperature led to an increase in the dark current and a decrease in the photocurrent. In addition, the impact of high temperature on the photocurrent gain mechanism was examined in detail based on carrier recombination and transport processes. In general, impressive robustness of the Ga2O3 MSM DUV PD was achieved, further stressing the detection capability of Ga2O3 DUV PDs in harsh environments.