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High‐speed and sensitive UV–Vis photodetectors have been constructed based on a typical 1D van der Waals material, antimony sulfide (Sb2S3). Impressively, the Sb2S3 nanowire photodetector demonstrates pronounced photosensitivity exhibiting a remarkable on/off ratio of ≈2800 under a power density of 318 mW cm−2. In addition, a high responsivity, an outstanding detectivity, and a short response/recovery time of 270 A W−1, 4.37 × 1013 Jones, and 10/12 ms are achieved. The competitive photosensitivity is associated with the intrinsic Mie resonance of the Sb2S3 nanowire, which is conducive to enhancing the coupling of the Sb2S3 photosensitive channel with incident light. By virtue of the unique 1D structural nature in both intrinsic and extrinsic perspectives, the Sb2S3 nanowire photodetectors manifest distinct polarization‐discriminating photoresponse with the optimal dichroic ratio reaching ≈7.2. Moreover, the Sb2S3 nanowire photodetectors demonstrate stable photoresponse from room temperature to 160 °C, and these nanodevices are durable against long‐term high‐temperature heating treatment at up to 300 °C. Taking advantage of the excellent thermal robustness, high‐temperature‐proof optoelectronic imaging and dual‐channel optical communication applications are demonstrated based on low‐dimensional van der Waals materials. On the whole, this study provides a new option for an advanced multifunctional optoelectronic system in extreme working environments. [ABSTRACT FROM AUTHOR]

Herein, a facile, catalyst-free, and dry topochemical transformation strategy for transforming the Bi2S3 nanowires to the Bi2Se3 nanowires, which has been realized through an atmospheric pressure high-temperature selenization treatment, has been developed. The complete topochemical transformation has been verified by combining x-ray diffraction, Raman spectroscopy, energy dispersive spectrometer, x-ray photoelectron spectroscopy, transmission electron microscopy, and selected area electron diffraction measurements. Systematical optical characterizations, including polarization-resolved optical microscopy images and polarization-dependent Raman spectra, have revealed the strong anisotropy of the Bi2Se3 nanowires. Furthermore, finite-different time-domain simulations have consolidated that the Bi2Se3 nanowires possess highly anisotropic absorption cross sections across the ultraviolet to far infrared spectral range, laying a solid foundation for the realization of ultra-broadband polarized optoelectronic applications. On the whole, this pioneering study depicts a unique avenue for topological material design accompanied with the integration of additional functionalities beyond the intrinsic counterparts, opening up an attractive research field for polarized photonics and optoelectronics. [ABSTRACT FROM AUTHOR]

The emergence of graphene has opened the prelude of extensive research on 2D layered materials. Especially, the diverse crystal structures and exceptional physical properties of multielement van der Waals semiconductors have provided a brand‐new platform for the implementation of novel optoelectronic devices. In this study, for the first time, the optoelectronic properties of a newly emerged quaternary van der Waals semiconductor, namely silver indium phosphorus sulfide (AgInP2S6), have been systematically investigated. It is revealed that the AgInP2S6 photodetector exhibits a fast response rate with the response/recovery time down to ≈1/2 ms. In addition, the AgInP2S6 device demonstrates stable photoswitching operation even under a high working temperature of up to 160 °C in the ambient environment without using any specific protection means, and the photoswitching characteristic is also well reserved after a 10‐h continuous heating at 150 °C in air. Profiting from the strong immunity to environmental thermal disturbance, a proof‐of‐concept high‐temperature optical communication application is demonstrated. In conclusion, this study provides an intriguing paradigm for the realization of the next‐generation optoelectronic devices against extreme working circumstances, which contributes to further broadening the scope of application of 2D material photodetectors in the upcoming future (e.g., space communication and tracking). [ABSTRACT FROM AUTHOR]

A van der Waals heterojunction photodetector has been constructed by vertically stacking a TaIrTe4 flake, a 2D type-II Weyl semimetal, and a WSe2 flake, a typical isotropic 2D semiconductor. Interestingly, the device exhibits a switchable operating mode depending on the direction of the voltage bias. Specifically, under a source-drain bias of −1 V, the device operates in a photovoltaic mode, featuring rapid response rate. Its response/recovery time is down to 22.5/25.1 ms, which is approximately one order of magnitude shorter than that of a pristine WSe2 photodetector (320/360 ms). In contrast, under a source-drain bias of +1 V, the device operates in a photoconductive mode with high photogain. The optimized responsivity reaches 9.1 A/W, and the corresponding external quantum efficiency and detectivity reach 2776% and 3.09 × 1012 Jones, respectively. Furthermore, the effective wavelength range of the TaIrTe4–WSe2 device has been extended to the long-wavelength region as compared to a WSe2 device. Beyond these, by virtue of the highly anisotropic crystal structure of TaIrTe4, the hybrid device exhibits polarized photosensitivity. Its anisotropy ratio reaches 1.72 (1.75) under a voltage bias of +1 (−1 V). On the whole, this research work provides a paradigm for the design and implementation of 2D materials based multifunctional optoelectronic devices. [ABSTRACT FROM AUTHOR]

In this study, cost-efficient atmospheric pressure chemical vapor deposition has been successfully developed to produce well-aligned high-quality monocrystalline Bi 2 S 3 nanowires. By virtue of surface strain-induced energy band reconstruction, the Bi 2 S 3 photodetectors demonstrate a broadband photoresponse across 370.6 to 1310 nm. Upon a gate voltage of 30 V, the responsivity, external quantum efficiency, and detectivity reach 23 760 A W -1 , 5.55 × 10 6 %, and 3.68 × 10 13 Jones, respectively. The outstanding photosensitivity is ascribed to the high-efficiency spacial separation of photocarriers, enabled by synergy of the axial built-in electric field and type-II band alignment, as well as the pronounced photogating effect. Moreover, a polarization-discriminating photoresponse has been unveiled. For the first time, the correlation between quantum confinement and dichroic ratio is systematically explored. The optoelectronic dichroism is established to be negatively correlated with the cross dimension ( i.e. , width and height) of the channel. Specifically, upon 405 nm illumination, the optimized dichroic ratio reaches 2.4, the highest value among the reported Bi 2 S 3 photodetectors. In the end, proof-of-concept multiplexing optical communications and broadband lensless polarimetric imaging have been implemented by exploiting the Bi 2 S 3 nanowire photodetectors as light-sensing functional units. This study develops a quantum tailoring strategy for tailoring the polarization properties of (quasi-)1D material photodetectors whilst depicting new horizons for the next-generation opto-electronics industry.

Two-dimensional (2D) magnetic materials are of wide research interest owing to their promising applications in spintronic devices. Among them, chromium chalcogenide compounds are some of the limited available systems that present both high stability in air and high Curie temperatures. Epitaxial growth techniques based on chemical vapour deposition (CVD) have been demonstrated to be a robust method for growing 2D non-layered chromium chalcogenides. However, the growth mechanism is not well-understood. Here, we demonstrate the epitaxial growth of Cr 3 Te 4 nanoplates with high quality on mica. Atomic-resolution scanning transmission electron microscopy (STEM) imaging reveals that the epitaxial growth is based on nanosized chromium oxide seed particles at the interface of Cr 3 Te 4 and mica. The chromium oxide nanoparticle exhibits a coherent interface with both mica and Cr 3 Te 4 with a lattice mismatch within 3%, suggesting that, as a buffer layer, chromium oxide can release the interfacial strain, and induce the growth of Cr 3 Te 4 although there is a distinct oxygen-content difference between mica and Cr 3 Te 4 . This work provides an experimental understanding behind the epitaxial growth of 2D magnetic materials at the atomic scale and facilitates the improvement of their growth procedures for devices with high crystalline quality., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)

Low light absorption and limited carrier lifetime are critical obstacles inhibiting further performance improvement of 2D layered material (2DLM) based photodetectors, while scalable fabrication is an ongoing challenge prior to commercialization from the lab to market. Herein, wafer-scale SnS/ZIS hierarchical nanofilms, where out-of-plane SnS (O-SnS) is modified onto in-plane ZIS (I-ZIS), have been achieved by pulsed-laser deposition. The derived O-SnS/I-ZIS photodetector exhibits markedly boosted sensitivity as compared to a pristine ZIS device. The synergy of multiple functionalities contributes to the dramatic improvement, including the pronounced light-trapping effect of O-SnS by multiple scattering, the high-efficiency spatial separation of photogenerated electron-hole pairs by a type-II staggered band alignment and the promoted carrier transport enabled by the tailored electronic structure of ZIS. Of note, the unique architecture of O-SnS/I-ZIS can considerably expedite the carrier dynamics, where O-SnS promotes the electron transfer from SnS to ZIS whilst the I-ZIS enables high-speed electron circulation. In addition, the interlayer transition enables the bridging of the effective optical window to telecommunication wavelengths. Moreover, monolithic integration of arrayed devices with satisfactory device-to-device variability has been encompassed and a proof-of-concept imaging application is demonstrated. On the whole, this study depicts a fascinating functional coupling architecture toward implementing chip-scale integrated optoelectronics.