No abstract

Among light-based free-space communication platforms, mid-infrared (MIR) light pertains to important applications in biomedical engineering, environmental monitoring, and remote sensing systems. Integrating MIR generation and reception in a network using two identical devices is vital for the miniaturization and simplification of MIR communications. However, conventional MIR emitters and receivers are not bidirectional due to intrinsic limitations of low performance and often require cryogenic cooling. Here, we demonstrate that macroscopic graphene fibres (GFs) assembled from weakly-coupled graphene layers allow room-temperature MIR detection and emission with megahertz modulation frequencies due to the persistence of photo-thermoelectric effect in millimeter-length and the ability to rapidly modulate gray-body radiation. Based on the dual-functionality of GFs, we set up a system that conducts bidirectional data transmission by switching modes between two identical GFs. The room-temperature operation of our systems and the potential to produce GFs on industrial textile-scale offer opportunities for simplified and wearable optical communications.

Graphene with linear energy dispersion and weak electron-phonon interaction is highly anticipated to harvest hot electrons in a broad wavelength range. However, the limited absorption and serious backscattering of hot-electrons result in inadequate quantum yields, especially in the mid-infrared range. Here, we report a macroscopic assembled graphene (nMAG) nanofilm/silicon heterojunction for ultrafast mid-infrared photodetection. The assembled Schottky diode works in 1.5-4.0 μm at room temperature with fast response (20-30 ns, rising time, 4 mm 2 window) and high detectivity (1.6 Â 10 11 to 1.9 Â 10 9 Jones from 1.5 to 4.0 μm) under the pulsed laser, outperforming single-layer-graphene/silicon photodetectors by 2-8 orders. These performances are attributed to the greatly enhanced Li Peng and Lixiang Liu contributed equally to this work.

Among various 1D materials, antimony selenide (Sb 2 Se 3) has the large visible to near-infrared (Vis-NIR) absorption cross section and excellent stability, thus it shows a huge potential to be applied as photodetectors. However, low electrical conductivity (10-6 Ω-1 •m-1 in bulk state) largely limits the extensive applications of Sb 2 Se 3. By a hot-injection based Sn/Sb substitution strategy,

GeSe micro‐sheets and micro‐belts have been synthesized by a facile one‐pot wet chemical method in 1‐octadecene solvent and oleic acid solvent, respectively. The adsorption of more oleic acid molecules on the (002) plane promoted growth along [010] direction of the GeSe micro‐belts and limited carrier transport in this direction, resulting in higher carrier concentration and mobility of the GeSe micro‐belts. The performance of the photodetectors based on the single GeSe micro‐sheet and the single GeSe micro‐belt was investigated under illumination at 532 nm, 980 nm and 1319 nm. Both, photodetectors based on a single GeSe micro‐sheet and a single GeSe micro‐belt, exhibit a high photoresponse, short response/recovery times, and long‐term durability. Moreover, the photodetector based on a single GeSe micro‐belt displays a broadband response with a high responsivity (5562 A/W at 532 nm, 1546 A/W at 980 nm) and detectivity (3.01×1012 Jones at 532 nm, 8.38×1011 Jones at 980 nm). These excellent characteristics render single GeSe micro‐belts very interesting for use as highly efficient photodetectors, especially in the NIR region.