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, azimuthdependent 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 polarizationdependent 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.

Two‐Dimensional Guanidine‐Based Hybrid Perovskites with Strong Dichroism for Multiwavelength Polarization‐Sensitive Detection

“…The dichroic ratios ( I max / I min ) are calculated to be 2.2, 1.29 and 1.23 for 520, 405 and 637 nm incident polarized‐light. For so large of these values, as far as we know, can be compared with those of some other 2D materials, such as PdSe 2 (∼2.2 and 1.8 for 369 and 532 nm, respectively), GeSe (∼2.16) and (TRA) 2 CsPb 2 Br 7 (∼2.1) (Figure S7 and Table S4, Supporting Information) [6,36,46] . Finally, the dichroic ratio of above‐mentioned three wavelengths of 10 crystal‐based devices was measured, the test results demonstrate that our devices hold large dichroic ratios (Figure 5d).…”

“…For so large of these values, as far as we know, can be compared with those of some other 2D materials, such as PdSe 2 (~2.2 and 1.8 for 369 and 532 nm, respectively), GeSe (~2.16) and (TRA) 2 CsPb 2 Br 7 (~2.1) (Figure S7 and Table S4, Supporting Information). [6,36,46] Finally, the dichroic ratio of above-mentioned three wavelengths of 10 crystal-based devices was measured, the test results demonstrate that our devices hold large dichroic ratios (Figure 5d). All these attributes make (BA) 2 (GA)Pb 2 I 7 as an inherent linear dichroic component for potential high-performance multiwavelength polarizationsensitive detection.…”

“…A complete "on/off" cycle was extracted from Figure 4d to obtain response time (τ), that the approximate values of rise and decay time are 320 μs and 315 μs, respectively, faster than majority of 2D inorganic system photodetectors. [46] All of these outstanding semiconductive characteristics of (BA) 2 (GA)Pb 2 I 7 meets the requirement of highperformance photodetection further the polarized-light detection.…”

2D NbOI2: A Chiral Semiconductor with Highly In‐Plane Anisotropic Electrical and Optical Properties

“…The value of R c /R b is 1.7 for the 2D NbOI 2 flake, which is comparable to 1.83, 2.2, 2.0, and 2.1 of 2D GeP, PdSe 2 , GeAs 2 , and GeS 2 flakes, respectively. [46][47][48] After exposure to the atmosphere for four months, the in-plane anisotropic photoresponsivity of the device remains unchanged, indicating its long-term stability (Figure S10, Supporting Information). The anisotropy factor of photoresponsivity of 2D NbOI 2 flake is larger than that of resistance.…”

Nondegenerate P‐Type In‐Doped SnS2 Monolayer Transistor

“…2D layered semiconductors with atomic thickness have become an important part of future electronics and optoelectronics for their unique chemical and physical properties. [ 9–20 ] A series of strategies, such as thickness modulation, [ 21,22 ] metal‐semiconductor interface improvement, [ 23 ] and doping, can affect the electrical performance of 2D materials. Among them, doping can effectively change the band structure of 2D materials and further regulate their electrical, [ 24–28 ] photoelectric, [ 7,29,30 ] and magnetic properties, [ 31–34 ] which can expand the application of 2D materials in future electronics/photonics systems.…”