Ultrahigh Responsivity β-Ga<sub>2</sub>O<sub>3</sub>/BP Junction Field Effect Phototransistors for UV/IR Dual-Band Detection
Tiwei Chen, Junrong Zhang, Xiaodong Zhang, Cheng Chen, Li Zhang, Yu Hu, Yongjian Ma, Xing Wei, Xin Zhou, Wenbo Tang, Yang An, Botong Li, Shige Dai, Lingling Xu, Wenhua Shi, Houqiang Fu, Yaming Fan, Yong Cai, Zhongming Zeng, Kai Zhang, Baoshun Zhang
Abstract
In this work, a dual-band junction field effect phototransistor (JFEPT) was fabricated by integrating p-type black phosphorus (BP) with Si-doped <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> . The operation principle of the JFEPT was systematically investigated by commercial TACD software SILVACO. The results indicate that the photocurrent is mainly formed by electrons under short-wave radiation, while it is composed of electrons and holes under long-wave irradiation. In addition, the Ga <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> O <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> doping concentration was determined to be <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3\times 10^{{16}}$ </tex-math></inline-formula> cm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{-{3}}$ </tex-math></inline-formula> to obtain a large photo-to-dark current ratio (PDCR). The threshold voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {th}}{)}$ </tex-math></inline-formula> of the fabrication JFEPT was 0.65 V, indicating that the device working in normally- OFF state. The drain current was <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 10^{-{6}}$ </tex-math></inline-formula> mA/mm and the ON/ OFF ratio is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10^{{5}}$ </tex-math></inline-formula> at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{G}$ </tex-math></inline-formula> = −4 V and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {DS}}$ </tex-math></inline-formula> = 5 V. And the device exhibits a low leakage current of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.84\times 10^{-{6}}$ </tex-math></inline-formula> mA/mm. Under 254- and 808-nm illumination, the PDCR were 14713.79 and 5.53, and the responsivity was calculated to be <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.39\times 10^{{6}}$ </tex-math></inline-formula> and 535 mA/W, respectively. In addition, a low noise current of 0.17 nA/Hz <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$^{\text {1/{2}}}$ </tex-math></inline-formula> at 1 Hz is beneficial for the device to detect the ultraweak optical signal. This work provides an important reference for the realization of high-performance UV-IR dual-band detector.