Wu Jing-Yuan, Jiang Hai-Yang, Wen Zhao-Yang, Wang Chun-Rui, Zhang Tong
Department of Optoelectronic Science and Engineering, College of Science, Donghua University, Shanghai 201620, China.
Joint International Research Laboratory of Information Display and Visualization, School of Electronic Science and Engineering, Southeast University, Nanjing 210096, China.
ACS Appl Mater Interfaces. 2024 Jun 26;16(25):32357-32366. doi: 10.1021/acsami.4c04023. Epub 2024 Jun 15.
Metal-semiconductor junctions play an important role in the development of electronic and optoelectronic devices. A Schottky junction photodetector based on two-dimensional (2D) materials is promising for self-powered photodetection with fast response speed and large signal-to-noise ratio. However, it usually suffers from an uncontrolled Schottky barrier due to the Fermi level pinning effect arising from the interface states. In this work, all-2D Schottky junctions with near-ideal Fermi level depinning are realized, attributed to the high-quality interface between 2D semimetals and semiconductors. We further demonstrate asymmetric diodes based on multilayer graphene/MoS/PtSe with a current rectification ratio exceeding 10 and an ideality factor of 1.2. Scanning photocurrent mapping shows that the photocurrent generation mechanism in the heterostructure switches from photovoltaic effect to photogating effect at varying drain biases, indicating both energy conversion and optical sensing are realized in a single device. In the photovoltaic mode, the photodetector is self-powered with a response time smaller than 100 μs under the illumination of a 405 nm laser. In the photogating mode, the photodetector exhibits a high responsivity up to 460 A/W originating from a high photogain. Finally, the photodetector is employed for single-pixel imaging, demonstrating its high-contrast photodetection ability. This work provides insight into the development of high-performance self-powered photodetectors based on 2D Schottky junctions.
金属-半导体结在电子和光电器件的发展中起着重要作用。基于二维（2D）材料的肖特基结光电探测器有望实现自供电光探测，具有快速响应速度和大信噪比。然而，由于界面态引起的费米能级钉扎效应，它通常会受到不受控制的肖特基势垒的影响。在这项工作中，实现了具有近乎理想费米能级脱钉的全二维肖特基结，这归因于二维半金属和半导体之间的高质量界面。我们进一步展示了基于多层石墨烯/MoS/PtSe的非对称二极管，其电流整流比超过10，理想因子为1.2。扫描光电流映射表明，在不同的漏极偏压下，异质结构中的光电流产生机制从光伏效应转变为光门控效应，这表明在单个器件中实现了能量转换和光学传感。在光伏模式下，该光电探测器在405 nm激光照射下自供电，响应时间小于100 μs。在光门控模式下，该光电探测器由于高光增益而表现出高达460 A/W的高响应度。最后，该光电探测器被用于单像素成像，展示了其高对比度光探测能力。这项工作为基于二维肖特基结的高性能自供电光电探测器的发展提供了见解。
