Amorphous Ga<sub>2</sub>O<sub>3</sub>/IGZO Heterojunction Thin-Film Solar-Blind Phototransistors With High Responsivity
Xingqi Ji, Xuemei Yin, Zijian Ding, Shiqi Yan, Xinyu Zhou, Jiawei Zhang, Qian Xin, Aimin Song
Abstract
High-performance phototransistors based on sputtered amorphous ultrathin 15-nm-Ga2O3/9-nm-IGZO heterojunction were fabricated and achieved excellent solar-blind detection performances under 254-nm light illumination with the short rise detection time of 1.18 s, the responsivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.35\times 10^{{3}}\text{A}\cdot \text{W}^{-{1}}$ </tex-math></inline-formula> , detectivity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2.56\times 10^{{17}}$ </tex-math></inline-formula> Jones, and photo-to-dark current ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$5.21\times 10^{{6}}$ </tex-math></inline-formula> . Compared with those of the reference single layer amorphous Ga2O3 and IGZO phototransistors, the Ga2O3/IGZO phototransistors show much higher performances, and this is attributed to the synergistic effect of the effective photocarrier generation in the wide bandgap Ga2O3 layer, the effective separation of the photocarriers at the heterojunction, and the enhanced electron transport in the IGZO channel layer. Furthermore, a high contrast solar-blind imaging of an “N” pattern was realized with the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$10\times10$ </tex-math></inline-formula> array based on these Ga2O3/IGZO phototransistors. The superior solar-blind detection performances, the large area and mass produced sputtering method, and the low maximum preparation temperature of 170°C of these amorphous Ga2O3/IGZO phototransistors, indicate their great application potential in flexible solar-blind imaging and photoelectronic integrated circuits.