Van der Waals Integrated LiNbO<sub>3</sub>/WS<sub>2</sub> for High‐Performance UV–Vis–NIR Photodetection
Xijie Liang, Heyuan Guan, Kaiwen Luo, Zhigang He, Aijie Liang, Weina Zhang, Qijing Lin, Zuoxin Yang, Haoran Zhang, Cheng Xu, Hanrong Xie, Fengli Liu, Fengkai Ma, Tiefeng Yang, Huihui Lu
Abstract
Abstract Lithium niobate (LN) is widely used in various optoelectronic systems due to its structural anisotropy and ferroelectric feature, which is one of the most essential platforms for next‐generation integrated optoelectronics. However, the insulating and optically transparent characteristics of LN have greatly limited the application in photodetection. Here, a high‐performance LN/WS 2 based photodetector is achieved through a van der Waals integration strategy in which the pyroelectric property of LN and the moderate bandgap of WS 2 are well combined. Upon light illumination, the light induced carriers in WS 2 would increase and the pyroelectric charges of LN will cross the interfacial gap and asymmetrically inject into the WS 2 , creating an n − /n + homojunction, thus improving the on‐state current. Under dark conditions, the sudden removal of the laser would introduce an instantaneous enhancement of polarization in the LN lattice, leading to an improved confinement on the remaining carriers in WS 2 , achieving a lower dark current. In this regard, the configurated device acquires a high on/off ratio more than 10 4 under zero bias, which represents the best among all the reported LN‐based photodetectors. This work realizes the complementary integration of 2D materials and ferroelectric LN and provides a feasible way for high‐performance photodetectors based on the LN platform.