薄层 MoS₂ 光电导效应的太赫兹近场显微研究

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中图分类号：0433文献标志码：A

Terahertz near-field microscopic study of photoconductive effect of thin layer MoS2

LI Xuebao， YOU Guanjun （School of Optical-Electrical and Computer Engineering， University of Shanghai for Science and Technology， Shanghai200093，China）

Abstract： This study demonstrates the photoconductive effect of thin layer MoS2 and the influence of MoS2/ substrate interface on its photoconductive effect at the nanoscale by using a terahertz scattering-type scanning near-field optical microscopy （THz s-SNOM）. When the thin layer MoS2 wasexcited with visible light，the THz near-field signal under visible light excitation was significantly increased compared to that without light excitation， indicating the occurrence of photoconductive effect in thin layer MoS2 . After the excitation laser was turned off， the thin layer MoS2 exhibited persistent photoconductivity， which was due to the photo-generated carriers being captured by the defect states. Under the same photoexcitation conditions， inserting h-BN between MoS2 and SiO2 resulted in a two-thirds reduction in the photoconductive effect of thin layer MoS2 indicating the significant impact of the MoS2/ substrate interface on the photoconductive effect of thin layer MoS2 . The research results demonstrate that the THz s-SNOM system， with its nanoscale spatial resolution and high sensitivity in carrier concentration detection， presents unique advantages in characterizing the optical properties of two-dimensional semiconductor materials.

Keywords：terahertzscattering-typescanningnear-field opticalmicroscopy； MoS2 photoconductive effect; persistent photoconductivity

二维材料具有独特的物理性质和广阔的应用前景，已经成为材料科学的一个研究热点。（剩余11573字）