High‐Performance Photodetector based on a 3D Dirac Semimetal Cd₃As₂/Tungsten Disulfide (WS₂) van der Waals Heterojunction

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.