Type-II Bi<sub>2</sub>O<sub>2</sub>Se/MoTe<sub>2</sub> van der Waals Heterostructure Photodetectors with High Gate-Modulation Photovoltaic Performance
Zhiying Dan, Baoxiang Yang, Qiqi Song, Jianru Chen, Hengyi Li, Wei Gao, Le Huang, Menglong Zhang, Mengmeng Yang, Zhaoqiang Zheng, Nengjie Huo, Lixiang Han, Jingbo Li
Abstract
In recent years, two-dimensional (2D) nonlayered Bi 2 O 2 Se-based electronics and optoelectronics have drawn enormous attention owing to their high electron mobility, facile synthetic process, stability to the atmosphere, and moderate narrow band gaps. However, 2D Bi 2 O 2 Se-based photodetectors typically present large dark current, relatively slow response speed, and persistent photoconductivity effect, limiting further improvement in fast-response imaging sensors and low-consumption broadband detection. Herein, a Bi 2 O 2 Se/2H-MoTe 2 van der Waals (vdWs) heterostructure obtained from the chemical vapor deposition (CVD) approach and vertical stacking is reported. The proposed type-II staggered band alignment desirable for suppression of dark current and separation of photoinduced carriers is confirmed by density functional theory (DFT) calculations, accompanied by strong interlayer coupling and efficient built-in potential at the junction. Consequently, a stable visible (405 nm) to near-infrared (1310 nm) response capability, a self-driven prominent responsivity ( R ) of 1.24 A·W –1, and a high specific detectivity ( D *) of 3.73 × 10 11 Jones under 405 nm are achieved. In particular, R, D *, fill factor, and photoelectrical conversion efficiency (PCE) can be enhanced to 4.96 A·W –1, 3.84 × 10 12 Jones, 0.52, and 7.21% at V g = −60 V through a large band offset originated from the n + –p junction. It is suggested that the present vdWs heterostructure is a promising candidate for logical integrated circuits, image sensors, and low-power consumption detection.