Broadband Visible−Near Infrared Two‐Dimensional WSe<sub>2</sub>/In<sub>2</sub>Se<sub>3</sub> Photodetector for Underwater Optical Communications
Jihua Zou, Yizhen Ke, Xiangyu Zhou, Yixuan Huang, Wen Du, Lin Lin, Shunyong Wei, Lingzhi Luo, Hezhuang Liu, Chuanlin Li, Kai Shen, Aobo Ren, Jiang Wu
Abstract
Abstract P–n junctions based on 2D materials can be achieved using a selective doping technique, while such a method is challenged by the complex fabrication process. Here, a facile van der Waals (vdWs) structured p–n heterojunction is demonstrated by simply transferring an n‐type multilayer α‐In 2 Se 3 (direct bandgap) on a p‐type ultra‐thin WSe 2 nanosheet. The vdWs stacked photodetector with an improved type‐II band alignment not only realizes a broadband spectral response from visible to near infrared (405–905 nm), but also operates well with a diode‐like behavior. This behavior is further confirmed by the high‐resolution scanning photocurrent mapping. As a result, the as‐fabricated device exhibits a short response time (<120 µs) and a high responsivity of 1.84 A W −1 under 520 nm laser illumination. Accordingly, an underwater optical communication system based on the WSe 2 /α‐In 2 Se 3 p‐n heterojunction photodetector is demonstrated, which is promising for next‐generation high‐performance and low‐power detection applications.