Wu Di, Guo Jiawen, Wang Chaoqiang, Ren Xiaoyan, Chen Yongsheng, Lin Pei, Zeng Longhui, Shi Zhifeng, Li Xin Jian, Shan Chong-Xin, Jie Jiansheng
School of Physics and Microelectronics, and Key Laboratory of Material Physics, Ministry of Education, Zhengzhou University, Zhengzhou, Henan 450052, China.
Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123, China.
ACS Nano. 2021 Jun 22;15(6):10119-10129. doi: 10.1021/acsnano.1c02007. Epub 2021 May 23.
Broadband photodetectors are of great importance for numerous optoelectronic applications. Two-dimensional (2D) tungsten disulfide (WS), an important family member of transition-metal dichalcogenides (TMDs), has shown great potential for high-sensitivity photodetection due to its extraordinary properties. However, the inherent large bandgap of WS and the strong interface recombination impede the actualization of high-sensitivity broadband photodetectors. Here, we demonstrate the fabrication of an ultrabroadband WS/Ge heterojunction photodetector through defect engineering and interface passivation. Thanks to the narrowed bandgap of WS induced by the vacancy defects, the effective surface modification with an ultrathin AlO layer, and the well-designed vertical nn heterojunction structure, the WS/AlO/Ge photodetector exhibits an excellent device performance in terms of a high responsivity of 634.5 mA/W, a large specific detectivity up to 4.3 × 10 Jones, and an ultrafast response speed. Significantly, the device possesses an ultrawide spectral response spanning from deep ultraviolet (200 nm) to mid-wave infrared (MWIR) of 4.6 μm, along with a superior MWIR imaging capability at room temperature. The detection range has surpassed the WS-based photodetectors in previous reports and is among the broadest for TMD-based photodetectors. Our work provides a strategy for the fabrication of high-performance ultrabroadband photodetectors based on 2D TMD materials.
宽带光电探测器对于众多光电子应用而言至关重要。二维（2D）二硫化钨（WS₂）作为过渡金属二硫属化物（TMDs）的重要家族成员，因其非凡特性在高灵敏度光电探测方面展现出巨大潜力。然而，WS₂固有的大带隙以及强烈的界面复合阻碍了高灵敏度宽带光电探测器的实现。在此，我们通过缺陷工程和界面钝化展示了一种超宽带WS₂/Ge异质结光电探测器的制备。得益于空位缺陷引起的WS₂带隙变窄、超薄Al₂O₃层的有效表面改性以及精心设计的垂直n⁺n异质结结构，WS₂/Al₂O₃/Ge光电探测器在高响应度634.5 mA/W、高达4.3×10¹² Jones的大比探测率以及超快响应速度方面展现出优异的器件性能。值得注意的是，该器件拥有从深紫外（200 nm）到4.6 μm中波红外（MWIR）的超宽光谱响应，以及在室温下卓越的MWIR成像能力。其探测范围超过了先前报道中的基于WS₂的光电探测器，并且在基于TMD的光电探测器中属于最宽的之一。我们的工作为基于二维TMD材料制备高性能超宽带光电探测器提供了一种策略。
