单层MoS_(2)和WS_(2)的太赫兹近场显微成像研究  

Terahertz near-field microscopic imaging study of monolayer MoS_(2) and WS_(2)

作　　者：叶鑫林 游冠军 YE Xinlin;YOU Guanjun(School of Optical-Electrical and Computer Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学光电信息与计算机工程学院,上海200093

出　　处：《光学仪器》2022年第1期63-69,共7页Optical Instruments

基　　金：国家重点研发计划(2017YFF0106304,2016YFF0200306)。

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MoS_(2)和WS_(2)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,MoS_(2)的太赫兹近场响应强于WS_(2),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。In this paper,the terahertz near-field response of monolayer MoS_(2) and WS_(2) 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 MoS_(2) is stronger than that of WS_(2),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.

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 

分 类 号：O433[机械工程—光学工程]