Jiang Jie, Ling Chongyi, Xu Tao, Wang Wenhui, Niu Xianghong, Zafar Amina, Yan Zhenzhong, Wang Xiaomu, You Yumeng, Sun Litao, Lu Junpeng, Wang Jinlan, Ni Zhenhua
School of Physics and Key Laboratory of MEMS of the Ministry of Education, Southeast University, Nanjing, 211189, China.
SEU-FEI Nano-Pico Center, Key Laboratory of MEMS of Ministry of Education, Southeast University, Nanjing, 210096, China.
Adv Mater. 2018 Aug 31:e1804332. doi: 10.1002/adma.201804332.
Defect-induced trap states are essential in determining the performance of semiconductor photodetectors. The de-trap time of carriers from a deep trap can be prolonged by several orders of magnitude as compared to shallow traps, resulting in additional decay/response time of the device. Here, it is demonstrated that the trap states in 2D ReS can be efficiently modulated by defect engineering through molecule decoration. The deep traps that greatly prolong the response time can be mostly filled by protoporphyrin molecules. At the same time, carrier recombination and shallow traps in-turn play dominant roles in determining the decay time of the device, which can be several orders of magnitude faster than the as-prepared device. Moreover, the specific detectivity of the device is enhanced (as high as ≈1.89 × 10 Jones) due to the significant reduction of the dark current through charge transfer between ReS and molecules. Defect engineering of trap states therefore provides a solution to achieve photodetectors with both high responsivity and fast response.
缺陷诱导的陷阱态对于决定半导体光电探测器的性能至关重要。与浅陷阱相比，载流子从深陷阱的脱陷阱时间可以延长几个数量级，从而导致器件额外的衰减/响应时间。在此，证明了二维ReS中的陷阱态可以通过分子修饰的缺陷工程有效地调制。极大延长响应时间的深陷阱可以大部分被原卟啉分子填充。同时，载流子复合和浅陷阱反过来在决定器件的衰减时间方面起主导作用，其比制备的器件快几个数量级。此外，由于通过ReS与分子之间的电荷转移显著降低了暗电流，器件的比探测率得到提高（高达≈1.89×10琼斯）。因此，陷阱态的缺陷工程为实现具有高响应度和快速响应的光电探测器提供了解决方案。
