Temperature Dependence of Self-Powered Photodetection Performance in Hybrid ε -Ga₂O₃/PEDOT:PSS Heterojunction

Abstract

With the capacity to separate electron-hole pairs under zero bias, the heterojunction photodetectors (PDs) can operate in self-powered manner, while it remains a challenge to maintain high self-powered photodetection performance at an elevated temperature. Herein, a hybrid <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula>-Ga2O3/PEDOT:PSS heterojunction deep ultraviolet (UV) PD was fabricated via the spin-coating method. The designed PD showed excellent signal-to-noise-ratio at room temperature (RT) with a dark current of 35 fA and photocurrent of 55 nA under zero bias. Even at the temperature of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$150~^{\circ }$ </tex-math></inline-formula>C, the PD could still maintain high photograph to a 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">$1\times 10^{{5}}$ </tex-math></inline-formula> and decent responsivity of 1.8 mA/W. As the temperature rising, the dark current of the constructed hybrid heterojunction increased while the photocurrent decreased, which were possibly caused by the enhancement of thermal excitation and the recombination of electron-hole pairs. The outstanding self-powered photoelectrical properties performed at high temperature reveal the great potential of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\varepsilon $ </tex-math></inline-formula>-Ga2O3/PEDOT:PSS heterojunction PDs for future low-power harsh environment photodetection.

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