Abstract

Near infrared polarized photodetectors are widely used, and van der Waals heterostructures based on transition metal dichalcogenides are important platforms for device research and application. Homologous polymorphic two-dimensional chalcogenides refer to two-dimensional chalcogenides with the same chemical composition but different crystal structures. Homologous polymorphic two-dimensional chalcogenides have shown great potential in near-infrared detection due to their unique bandgap characteristics, exciton effects, and controllable optoelectronic properties.

This paper studies a near-infrared polarized photodetector based on 1T'-MoTe₂/2H-MoTe₂ structure, in which the semimetallic 1T'-MoTe₂ has attracted attention due to its low work function and excellent electrical performance. 1T'-MoTe₂ and 2H-MoTe₂ form a favorable bandgap structure after forming a heterojunction, which improves carrier separation efficiency and photoelectric response. This device exhibits excellent high-sensitivity optoelectronic detection performance in the wideband region (532–2200 nm), such as significant high responsivity (3.06 A·W–1) under 1310 nm laser, specific detectivity (3.2 × 109 Jones), good external quantum efficiency (289%), and fast rise and decay response times of 10.56 ms/6.26 ms.

In addition, the device has polarization detection capability, achieving a high polarization sensitivity of 20.1. The device has successfully achieved imaging from visible light to near-infrared light, highlighting the potential of 1T'-MoTe₂/2H-MoTe₂ heterojunction as a polarization sensitive detector.