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| 单层MoS2和WS2的太赫兹近场显微成像研究 |
| Terahertz near-field microscopic imaging study of monolayer MoS2 and WS2 |
| 投稿时间：2021-03-22 |
| DOI：10.3969/j.issn.1005-5630.2022.01.010 |
| 中文关键词: 太赫兹散射式近场光学显微镜 二硫化钼 二硫化钨 光生载流子分布 近场成像 |
| 英文关键词:terahertz scattering-type near-field optical microscope MoS2 WS2 photo-generated carrier distribution near-field imaging |
| 基金项目:国家重点研发计划（2017YFF0106304, 2016YFF0200306） |
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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（THz s-SNOM）研究了化学气相沉积法制备的单层MoS2和WS2晶粒的太赫兹近场响应。在没有可见光激发时，未探测到可分辨的太赫兹近场响应，说明晶粒具有较低的掺杂载流子浓度。有可见光激发时，由于光生载流子的太赫兹近场响应，能够测得与晶粒轮廓完全吻合的太赫兹近场显微图。在相同的光激发条件下，MoS2的太赫兹近场响应强于WS2，反映了两者之间载流子浓度或迁移率的差异。研究结果表明，THz s-SNOM兼具超高的空间分辨率和对光生载流子的灵敏探测能力，对二维半导体材料和器件光电特性的微观机理研究具有独特的优势。 |
| 英文摘要: |
| In this paper, the terahertz near-field response of monolayer MoS2 and WS2 grains prepared by chemical vapor deposition was investigated by terahertz scattering scanning near-field optical microscopy (THz s-SNOM). No resolvable terahertz near-field response was detected in the absence of visible excitation, indicating that the grains have a low doped carrier concentration. With visible light excitation, we were able to measure a terahertz near-field micrograph that exactly matches the grain profile due to the terahertz near-field response of the photogenerated carriers. Under the same photoexcitation conditions, the terahertz near-field response of MoS2 is stronger than that of WS2, it reflects the difference of carrier concentration or mobility between them. The results show that THz s-SNOM combines ultra-high spatial resolution and sensitive detection of photogenerated carriers. It is uniquely suited for micromechanics studies of the optoelectronic properties of two-dimensional semiconductor materials and devices. |
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