Highly In‐Plane Anisotropic 2D PdSe2 for Polarized Photodetection with Orientation Selectivity

Abstract Polarized photodetection based on anisotropic two‐dimensional materials display promising prospects for practical application in optical communication and optoelectronic fields. However, most of the reported polarized photodetection are limited by the lack of valid tunable strategy and low linear dichroism ratio. A peculiar noble metal dichalcogenide—PdSe 2 with a puckered pentagonal structure and abnormal linear dichroism conversion—potentially removes these restrictions and is demonstrated in this study. Herein, azimuth‐dependent reflectance difference microscopy combined with anisotropic electrical transport measurements indicate strong in‐plane anisotropic optical and electrical properties of two‐dimensional PdSe 2 . Remarkably, the typical polarization‐resolved photodetection exhibits anisotropic photodetection characteristics with a dichroic ratio up to ≈1.8 at 532 nm and ≈2.2 at 369 nm, and their dominant polarization orientation differs by 90° corresponding to the a ‐axis and b ‐axis, respectively. The unique orientation selection behavior in polarization‐dependent photodetection can be attributed to the intrinsic linear dichroism conversion. The results make 2D PdSe 2 a promising platform for investigating anisotropic structure–property correlations and integrated optical applications for novel polarization‐sensitive photodetection.