Masanta Suvadip, Nayak Chumki, Agarwal Pooja, Das Kaustuv, Singha Achintya
Department of Physics, Bose Institute, 93/1 Acharya Prafulla Chandra Road, Kolkata 700009, India.
Saha Institute of Nuclear Physics, HBNI, Kolkata 700064, India.
ACS Appl Mater Interfaces. 2023 Mar 7. doi: 10.1021/acsami.2c20707.
Transition metal dichalcogenides (TMDCs) are potential two-dimentional materials as natural partners of graphene for highly responsive van der Waals (vdW) heterostructure photodetectors. However, the spectral detection range of the detectors is limited by the optical bandgap of the TMDC, which acts as a light-absorbing medium. Bandgap engineering by making alloy TMDC has evolved as a suitable approach for the development of wide-band photodetectors. Here, broadband (visible to near-infrared) photodetection with high sensitivity in the near-infrared region is demonstrated in a MoSSe/graphene heterostructure. In the ambient environment, the photodetector exhibits high responsivity of 0.6 × 10 A/W and detectivity of 7.9 × 10 Jones at 800 nm excitation with a power density of 17 fW/μm and 10 mV source-drain bias. The photodetector shows appreciable responsivity in self-bias mode due to nonuniform distribution of MoSSe flakes on the graphene layer between the source and drain end and the asymmetry between the two electrodes. Time-dependent photocurrent measurements show fast rise/decay times of ∼38 ms/∼48 ms. A significant gate tunability on the efficiency of the detector has been demonstrated. The device is capable of low power detection and exhibits high operational frequency, gain, and bandwidth. Thus, the MoSSe/graphene heterostructure can be a promising candidate as a high-speed and highly sensitive near-infrared photodetector capable of operating at ambient conditions with low energy consumption.
过渡金属二硫属化物（TMDCs）作为石墨烯的天然伙伴，是用于高响应性范德华（vdW）异质结构光电探测器的潜在二维材料。然而，探测器的光谱检测范围受到作为光吸收介质的TMDC的光学带隙的限制。通过制备合金TMDC进行带隙工程已发展成为开发宽带光电探测器的一种合适方法。在此，在MoSSe/石墨烯异质结构中展示了在近红外区域具有高灵敏度的宽带（可见光到近红外）光电探测。在环境环境中，该光电探测器在800 nm激发下，功率密度为17 fW/μm且源漏偏压为10 mV时，表现出0.6×10 A/W的高响应度和7.9×10琼斯的探测率。由于源极和漏极端之间的石墨烯层上MoSSe薄片的不均匀分布以及两个电极之间的不对称性，该光电探测器在自偏压模式下显示出可观的响应度。随时间变化的光电流测量显示快速上升/下降时间约为38 ms/约48 ms。已证明对探测器效率有显著的栅极可调性。该器件能够进行低功耗检测，并具有高工作频率、增益和带宽。因此，MoSSe/石墨烯异质结构有望成为一种能够在环境条件下以低能耗运行的高速、高灵敏度近红外光电探测器。
