Gate-tunable polarization-sensitive broadband photodetector based on PdSe₂/2H-MoTe₂heterostructure

The vertical stacking of diverse materials provides a versatile platform for constructing multifunctional optoelectronic devices. However, for layered anisotropic materials, which can offer an additional degree of freedom to control in-plane optoelectronic performance, their stacking for multifunctional device applications remains limited. Here, an anisotropic PdSe₂/2 H-MoTe₂van der Waals heterojunction is designed and fabricated, and gate-programmable photocurrent polarity reversal and operation-mode switching for polarization-sensitive broadband photodetection. Benefiting from the dual-gate tunability of the 2 H-MoTe₂, the reversible photoconductive and photovoltaic operation modes are realized, where an enhanced rectification ratio of 9.2 × 10³at a positive gate bias and a pronounced negative photoresponse with an extremelyRof -25.6 A W^-1at a negative gate bias are highlighted. Broadband detection from 520 to 2000 nm with a peak responsivity of 151.1 A W^-1and polarization-dependent photoresponse from 520 to 1550 nm with a maximum polarization ratio up to 3.34 are demonstrated. Such multifunctional integration offers new insights into developing the highly integrated and intelligent optoelectronic systems by constructing the anisotropic heterostructures.