Direct Light Orbital Angular Momentum Detection in Mid-Infrared Based on the Type-II Weyl Semimetal TaIrTe4

Wafer-Scale Atomic Assembly for 2D Multinary Transition Metal Dichalcogenides for Visible and NIR Photodetection

The tunable properties of 2D transition-metal dichalcogenide (TMDs) materials are extensively investigated for high-performance and wavelength-tunable optoelectronic applications. However, the precise modification of large-scale systems for practical optoelectronic applications remains a challenge. In this study, a wafer-scale atomic assembly process to produce 2D multinary (binary, ternary, and quaternary) TMDs for broadband photodetection is demonstrated. The large-area growth of homogeneous MoS2, Ni0.06Mo0.26S0.68, and Ni0.1Mo0.9S1.79Se0.21 is carried out using a succinct coating of the single-source precursor and subsequent thermal decomposition combined with thermal evaporation of the chalcogen powder. The optoelectrical properties of the multinary TMDs are dependent on the combination of heteroatoms. The maximum photoresponsivity of the MoS2-, Ni0.06Mo0.26S0.68-, and Ni0.1Mo0.9S1.79Se0.21-based photodetectors is 3.51 × 10-4, 1.48, and 0.9 A W-1 for 532 nm and 0.063, 0.42, and 1.4 A W-1 for 1064 nm, respectively. The devices exhibited excellent photoelectrical properties, which is highly beneficial for visible and near-infrared (NIR) photodetection.

Low-Dimensional-Materials-Based Photodetectors for Next-Generation Polarized Detection and Imaging

The vector characteristics of light and the vectorial transformations during its transmission lay a foundation for polarized photodetection of objects, which broadens the applications of related detectors in complex environments. With the breakthrough of low-dimensional materials (LDMs) in optics and electronics over the past few years, the combination of these novel LDMs and traditional working modes is expected to bring new development opportunities in this field. Here, the state-of-the-art progress of LDMs, as polarization-sensitive components in polarized photodetection and even the imaging, is the main focus, with emphasis on the relationship between traditional working principle of polarized photodetectors (PPs) and photoresponse mechanisms of LDMs. Particularly, from the view of constitutive equations, the existing works are reorganized, reclassified, and reviewed. Perspectives on the opportunities and challenges are also discussed. It is hoped that this work can provide a more general overview in the use of LDMs in this field, sorting out the way of related devices for "more than Moore" or even the "beyond Moore" research.

Mid-Infrared Bipolar and Unipolar Linear Polarization Detections in Nb2 GeTe4 /MoS2 Heterostructures

Detecting and distinguishing light polarization states, one of the most basic elements of optical fields, have significant importance in both scientific studies and industry applications. Artificially fabricated structures, e.g., metasurfaces with anisotropic absorptions, have shown the capabilities of detecting polarization light and controlling. However, their operations mainly rely on resonant absorptions based on structural designs that are usually narrow bands. Here, a mid-infrared (MIR) broadband polarization photodetector with high PRs and wavelength-dependent polarities using a 2D anisotropic/isotropic Nb2 GeTe4 /MoS2 van der Waals (vdWs) heterostructure is demonstrated. It is shown that the photodetector exhibits high PRs of 48 and 34 at 4.6  and 11.0 µm wavelengths, respectively, and even a negative PR of -3.38 for 3.7 µm under the zero bias condition at room temperature. Such interesting results can be attributed to the superimposed effects of a photovoltaic (PV) mechanism in the Nb2 GeTe4 /MoS2 hetero-junction region and a bolometric mechanism in the MoS2 layer. Furthermore, the photodetector demonstrates its effectiveness in bipolar and unipolar polarization encoding communications and polarization imaging enabled by its unique and high PRs.

Impinge Weyl advantages on light

Weyl semimetals are emerging topological materials with intriguing physical properties. Now this exotic matter may lead to novel photonic and optoelectronic applications.

Two-Dimensional Van Der Waals Topological Materials: Preparation, Properties, and Device Applications

Over the past decade, 2D van der Waals (vdW) topological materials (TMs), including topological insulators and topological semimetals, which combine atomically flat 2D layers and topologically nontrivial band structures, have attracted increasing attention in condensed-matter physics and materials science. These easily cleavable and integrated TMs provide the ideal platform for exploring topological physics in the 2D limit, where new physical phenomena may emerge, and represent a potential to control and investigate exotic properties and device applications in nanoscale topological phases. However, multifaced efforts are still necessary, which is the prerequisite for the practical application of 2D vdW TMs. Herein, this review focuses on the preparation, properties, and device applications of 2D vdW TMs. First, three common preparation strategies for 2D vdW TMs are summarized, including single crystal exfoliation, chemical vapor deposition, and molecular beam epitaxy. Second, the origin and regulation of various properties of 2D vdW TMs are introduced, involving electronic properties, transport properties, optoelectronic properties, thermoelectricity, ferroelectricity, and magnetism. Third, some device applications of 2D vdW TMs are presented, including field-effect transistors, memories, spintronic devices, and photodetectors. Finally, some significant challenges and opportunities for the practical application of 2D vdW TMs in 2D topological electronics are briefly addressed.