Simultaneous AoLP and DoLP Detection in a Bias‐Switchable PdSe₂ /MoS₂ /PdSe₂ Heterojunction for Polarization Discrimination

uch as black phosphorus (BP)[19–21] and PdSe2,[22–24] have garnered significant attention due to their in- plane anisotropy, layered structure, and unique optical and opto- electronic properties. The layered nature of 2D materials allows for the formation of van der Waals heterojunctions (vdWHs), such as, InSe/PdSe2,[25] 1T’-MoTe2/WSe2,[26] BP/hBN/BP,[27] BP/MoS2/BP,[28] b-AsP/MoS2/BP,[29] Nb2GeTe4//MoS2,[30] which can be tailored for specific functionalities and easily integrated with silicon-based chips without concerns of lattice mismatch.[31] This is pivotal in the realm of linear polarized light detection. Despite the progress made, the polarization de- tectors typically rely on photoconductivity or photovoltaic effect, where the polarity of the current signal obtained is determined by the bias voltage or the direction of the built-in potential, which can only produce unipolar photocurrents. This poses a fundamental challenge: in previous developed polarization detectors, the photocurrents measured at different angles of linear polarization (𝜃) overlap twice within the range of 0° to 180°, making it impossible to differentiate between 𝜃and (180° – 𝜃). Concurrently, the determination of AoLP and DoLP primarily relies on the well-established four-pixel methodology, which involves measurements at orientations of 0°, 45°, 90°, and 135°.[32–34] While effective, this approach has not yet enabled the direct calculation of AoLP and DoLP using a single chip-based detector. To address this gap, recent research has focused on advanc- ing AoLP and DoLP measurement systems by integrating meta- surface nanostructures with 2D materials or designing special- ized structures incorporating 2D materials. These innovations aim to facilitate the measurement of polarized light using a sin- gle device.[35–42] For instance, Wang et al. achieved full-Stokes polarization detection using metasurface nanostructures com- bined with 2D materials.[43] However, this approach is hindered by a complex fabrication process, high cost, and a narrow operat- ing wavelength range due to its resonance characteristics. Mean- while, Zhang et al. successfully measured the polarization angle and intensity of light through an innovative structural design,[44] but their method does not extend to the calculation of DoLP, and the b-AsP material used is known to be air-unstable. Given these limitations, there is a pressing need to develop a structurally ro- bust, single, integrated device capable of detecting both AoLP and DoLP. Herein, we present a novel bias-switchable unipolar bar- rier vdWH based on a PdSe2/MoS2/PdSe2 configuration, where PdSe2 serves as a carrier abso