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

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 (approximate to 5.3x10(4)) and a responsivity (R-i) of about 223.5AW(-1) at 520nm, as well as an outstanding detectivity (D*) of about 2.05x10(14) Jones at 808nm near-IR waveband. However, the optimized noise equivalent power (NEP) is evaluated about 6.17x10(-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.