Ultra-sensitive multi-band infrared polarization photodetector based on 1T'-MoTe₂/2H-MoTe₂ van der Waals heterostructure

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.