Oxygen-incorporated and layer-by-layer stacked WS2 nanosheets for broadband, self-driven and fast-response photodetection. Issue 14 (26th March 2019)

• Record Type: Journal Article
• Authors: Xu, Jun; Cheng, Xialan; Liu, Tong; Yu, Yongqiang; Song, Lingling; You, Yu; Wang, Tao; Zhang, Junjun
• Is Part Of: Nanoscale. Volume 11:Issue 14(2019)
• Page Start: 6810
• Page End: 6816
• Publication Date: 2019-03-26
• Subjects: Nanoscience -- Periodicals; Nanotechnology -- Periodicals; 620.505
• DOI: 10.1039/c8nr10350j
• Languages: English
• ISSNs: 2040-3364

Abstract

Abstract : Layer-by-layer stacked and oxygen-incorporated WS2 microrods that exhibit strong absorption in both the visible light region and the 1100–2000 nm NIR light region are synthesized and demonstrated as broadband, self-driven, fast-response photodetectors. Abstract : Two-dimensional (2D) layered WS2 nanosheets have been regarded as exciting and emerging candidate materials in constructing high performance photodetectors. In this work, we develop a facile solvothermal method to synthesize oxygen-doped WS2 microrods composed of layer-by-layer stacked nanosheets. The WS2 microrods exhibit an obvious bandgap of 1.2 eV, together with a broad near-infrared (NIR) absorption after 1100 nm. The unique absorption can be ascribed to the oxygen-incorporation-induced localized surface plasmon resonance (LSPR) effect. A hybrid WS2 /Si heterojunction, which allows the combination of the WS2 microrods with a mature silicon platform, is then constructed by a facile spin-coating fabrication process to investigate the photoresponse properties. Benefitting from the remarkable photovoltaic performance, the WS2 /Si heterojunction acts as a self-driven photodetector with outstanding characteristics. The photodetector exhibits a decent responsivity ( R ) of 1.5 A W −1, a high specific detectivity ( D *) of ∼2 × 10 12 Jones, fast response speeds with rise/fall times of 2.0/7.2 μs, and good ambient stability (2 months) at zero bias. Notably, the photodetector is still sensitive at a broadband wavelength in the NIR region (1100–2000 nm). The broadband response is attributed to the LSPR effect of the oxygen-incorporated WS2 . These results suggest great potential of the oxygen-incorporated WS2 /Si heterojunctions in NIR light detection.