High‐Performance Photodetector based on a 3D Dirac Semimetal Cd<sub>3</sub>As<sub>2</sub>/Tungsten Disulfide (WS<sub>2</sub>) van der Waals Heterojunction
Xingchao Zhang, Rui Pan, Yunkun Yang, Qi Han, Xianchao Liu, Chaoyi Zhang, Hongxi Zhou, Jiayue Han, Jun Gou, Jun Wang
Abstract
Recently, heterojunction photodetectors have attracted significant interest due to the multiple degrees of freedom reorganization, integrating advantages of different typed materials. Herein, a high‐performance photodetector based on a 3D Dirac semimetal Cd 3 As 2 /tungsten disulfide (WS 2 ) heterojunction is demonstrated, which is constructed by directly transferring exfoliated 2D few layer WS 2 on Cd 3 As 2 nano‐belt and following by annealing treatment. The resulting Cd 3 As 2 /WS 2 heterojunction device presents superior performance with a high on/off ratio (≈5.3 × 10 4 ) and a responsivity ( R i ) of about 223.5 AW −1 at 520 nm, as well as an outstanding detectivity ( D* ) of about 2.05 × 10 14 Jones at 808 nm near‐IR waveband. However, the optimized noise equivalent power (NEP) is evaluated about 6.17 × 10 −14 WHz −1/2 by the noise power density spectrum. The excellent performance can be attributed to a high‐quality heterostructure interface, strong light absorption capacity, and ultralow dark current in a Cd 3 As 2 /WS 2 heterojunction system. This work provides a promising platform to develop a high‐performance optoelectronic device based on 3D Dirac semimetal and 2D TMDs families.