Defect Engineering for Modulating the Trap States in 2D Photoconductors. Issue 40 (31st August 2018)

• Record Type: Journal Article
• Authors: 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
• Is Part Of: Advanced materials. Volume 30:Issue 40(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2018-08-31
• Subjects: defect engineering -- density functional theory -- photoconductive gain -- trap states -- 2D ReS2; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.201804332
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: 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 ReS2 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 13 Jones) due to the significant reduction of the dark current through charge transfer between ReS2 and molecules. Defect engineering of trap states therefore provides a solution to achieve photodetectors with both high responsivity and fast response. Abstract : Defect engineering can modulate the trap states and greatly improve the performance of 2D photoconductors. Deep traps in 2D ReS2 are passivated through defect engineering and molecule decoration. The response time is improved by several orders of magnitude. Moreover, the specific detectivity of the device is enhanced due to the significant reduction of dark current.