High-Performance and Polarization-Sensitive Imaging Photodetector Based on WS2 /Te Tunneling Heterostructure.

Abstract

Next-generation imaging systems require photodetectors with high sensitivity, polarization sensitivity, miniaturization, and integration. By virtue of their intriguing attributes, emerging 2D materials offer innovative avenues to meet these requirements. However, the current performance of 2Dphotodetectors is stillbelow the requirements forpractical application owing to the severe interfacial recombination, the lack of photoconductive gain, and insufficient photocarrier collection. Here, a tunneling dominant imaging photodetector based on WS2 /Te heterostructure is reported. This device demonstrates competitive performance, including a remarkable responsivity of 402 A W-1 , an outstanding detectivity of 9.28 × 1013 Jones, a fast rise/decay time of 1.7/3.2ms, and a high photocurrent anisotropic ratio of 2.5. These outstanding performances can be attributed to the type-I band alignment with carrier transmission barriers and photoinduced tunneling mechanism, allowing reduced interfacial trapping effect, effective photoconductive gains, and anisotropic collection of photocarriers. Significantly, the constructed photodetector is successfully integrated into a polarized light imaging system and an ultra-weak light imaging system to illustrate the imaging capability. These results suggest the promising application prospect of the device in future imaging systems.