摘要
采用太赫兹散射式扫描近场光学显微镜(terahertz scattering-type scanning near-field optical microscopy,THz s-SNOM),在纳米尺度上研究了薄层MoS_(2)的光电导效应以及MoS_(2)/衬底界面对其光电导效应的影响。对于薄层MoS_(2),可见光激发时其太赫兹近场信号相较于无光激发时明显增强,说明薄层MoS_(2)产生了光电导效应。在激发光关闭后,薄层MoS_(2)会表现出持久的光电导效应,这应该与光生载流子被缺陷态捕获有关。在相同的光激发条件下,在MoS_(2)和SiO_(2)之间插入h-BN后,薄层MoS_(2)的光电导效应强度降低了2/3,说明MoS_(2)/衬底界面对薄层MoS_(2)的光电导效应有重要影响。研究结果表明,THz s-SNOM系统以其纳米级的空间分辨率和高灵敏度的载流子浓度分辨能力,在二维半导体材料光电性质的表征方面具有独特的优势。
This study demonstrates the photoconductive effect of thin layer MoS_(2) and the influence of MoS_(2)/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 MoS_(2) was excited 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 MoS_(2).After the excitation laser was turned off,the thin layer MoS_(2) 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 MoS_(2) and SiO_(2) resulted in a two-thirds reduction in the photoconductive effect of thin layer MoS_(2),indicating the significant impact of the MoS_(2)/substrate interface on the photoconductive effect of thin layer MoS_(2).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.
作者
李学宝
游冠军
LI Xuebao;YOU Guanjun(School of Optical-Electrical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)
出处
《光学仪器》
2025年第6期66-73,共8页
Optical Instruments
基金
国家重点研发计划(2023YFF0719200)。
关键词
太赫兹散射式扫描近场光学显微镜
二硫化钼
光电导效应
持久光电导
terahertz scattering-type scanning near-field optical microscopy
MoS_(2)
photoconductive effect
persistent photoconductivity
