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| 薄层MoS2光电导效应的太赫兹近场显微研究 |
| Terahertz near-field microscopic study of photoconductive effect of thin layer MoS2 |
| 投稿时间:2024-04-02 |
| DOI:10.3969/j.issn.1005-5630.202404020066 |
| 中文关键词: 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 |
| 英文关键词:terahertz scattering-type scanning near-field optical microscopy MoS2 photoconductive effect persistent photoconductivity |
| 基金项目:国家重点研发计划(2023YFF0719200) |
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| 中文摘要: |
| 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MoS2的光电导效应以及MoS2/衬底界面对其光电导效应的影响。对于薄层MoS2,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MoS2产生了光电导效应。在激发光关闭后,薄层MoS2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MoS2和SiO2之间插入h-BN后,薄层MoS2的光电导效应强度降低了2/3,说明MoS2/衬底界面对薄层MoS2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。 |
| 英文摘要: |
| 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 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 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. |
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