Institute of Functional Nano and Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University , Suzhou 215123, P. R. China.
Department of Materials Science and Engineering, and ARC Centre of Excellence in Future Low-Energy Electronics Technologies (FLEET), Monash University , Clayton, Victoria 3800, Australia.
ACS Appl Mater Interfaces. 2017 Oct 18;9(41):36137-36145. doi: 10.1021/acsami.7b09889. Epub 2017 Oct 5.
The presence of a direct band gap and high carrier mobility in few-layer black phosphorus (BP) offers opportunities for using this material for infrared (IR) light detection. However, the poor air stability of BP and its large contact resistance with metals pose significant challenges to the fabrication of highly efficient IR photodetectors with long lifetimes. In this work, we demonstrate a graphene-BP heterostructure photodetector with ultrahigh responsivity and long-term stability at IR wavelengths. In our device architecture, the top layer of graphene functions not only as an encapsulation layer but also as a highly efficient transport layer. Under illumination, photoexcited electron-hole pairs generated in BP are separated and injected into graphene, significantly reducing the Schottky barrier between BP and the metal electrodes and leading to efficient photocurrent extraction. The graphene-BP heterostructure phototransistor exhibits a long-term photoresponse at near-infrared wavelength (1550 nm) with an ultrahigh photoresponsivity (up to 3.3 × 10 A W), a photoconductive gain (up to 1.13 × 10), and a rise time of about 4 ms. Considering the thickness-dependent band gap in BP, this material represents a powerful photodetection platform that is able to sustain high performance in the IR wavelength regime with potential applications in remote sensing, biological imaging, and environmental monitoring.
本征直接带隙和高载流子迁移率使得少层黑磷（BP）成为用于红外（IR）光探测的理想材料。然而，BP 的空气稳定性差及其与金属的大接触电阻对制备具有长寿命的高效 IR 光电探测器构成了重大挑战。在这项工作中，我们展示了一种具有超高响应度和长寿命的石墨烯-BP 异质结构光电探测器，用于 IR 波长。在我们的器件结构中，顶层石墨烯不仅作为封装层，而且作为高效输运层。在光照下，BP 中产生的光生电子-空穴对被分离并注入石墨烯中，这显著降低了 BP 和金属电极之间的肖特基势垒，从而实现了高效的光电流提取。该石墨烯-BP 异质结构光电晶体管在近红外波长（1550nm）下表现出长时的光响应，具有超高的光响应度（高达 3.3×10^4 A W^-1）、光电导增益（高达 1.13×10^3）和约 4ms 的上升时间。考虑到 BP 中厚度相关的带隙，这种材料代表了一种强大的光电探测平台，能够在 IR 波长范围内保持高性能，具有在遥感、生物成像和环境监测等领域的潜在应用。
