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 Cd3As2/tungsten disulfide (WS2) heterojunction is demonstrated, which is constructed by directly transferring exfoliated 2D few layer WS2 on Cd3As2 nano‐belt and following by annealing treatment. The resulting Cd3As2/WS2 heterojunction device presents superior performance with a high on/off ratio (≈5.3 × 104) and a responsivity (Ri) of about 223.5 AW−1 at 520 nm, as well as an outstanding detectivity (D*) of about 2.05 × 1014 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 Cd3As2/WS2 heterojunction system. This work provides a promising platform to develop a high‐performance optoelectronic device based on 3D Dirac semimetal and 2D TMDs families.

Keywords

• 3D Dirac semimetal
• Cd3As2
• heterojunction photodetectors
• tungsten disulfide
• ultra-low dark current