Nanostructure‐Assisted Enhanced MoTe ₂ /ReSe ₂ Heterostructures for Self‐Powered and Broad‐Spectral Photodetector

Abstract Photodetectors with broad‐spectrum sensitivity and high responsivity hold significant potential for applications across various domains, including optical communication and imaging. 2D transition metal dichalcogenides (TMDs) exhibit promising prospects in the realm of broad‐spectrum detection due to their distinct electrical and optical characteristics. These materials can be integrated through stacking to create van der Waals (vdW) heterostructure. Nevertheless, the inherent weak light absorption of such vdW heterojunctions limits their practical performance. In this study, a strategy is proposed to enhance the performance of vdW heterostructure by significantly improving light absorption through nanostructures with Mie‐type resonance. A photodetector based on a MoTe ₂ /ReSe ₂ heterojunction integrated with this Si nanostripe array (OA) achieves broadband photodetection spanning the visible to near‐infrared spectrum (405–1550 nm), with a peak responsivity of 277 A W ⁻¹ and a specific detectivity of 9.46×10 ¹² Jones at 532 nm. In particular, in self‐powered mode, the responsivity of MoTe ₂ /ReSe ₂ photodetector on the Si nanostripe optical array (4.58 A W ⁻¹ ) is nearly two orders of magnitude higher than that on the Si/SiO ₂ substrate. Additionally, the device exhibits a distinct polarization sensitivity (ratio of 2.2), attributed to the anisotropic optical properties of ReSe ₂ flakes, and demonstrates high‐contrast polarimetric imaging capabilities.