二维材料异质结构的时空分辨近场光谱研究

二维材料及其异质结构具有优异的光学、电学等性质，在未来的光电探测、能源转换等领域具有重要的应用前景。二维材料及其异质结构中纳米尺度的缺陷、局域掺杂等结构特征的光学信号通常被湮没在远场信号中，而这些缺陷、局域掺杂等对其物理化学性质以及器件性能具有不可忽略的影响。但在常规的光学和光谱表征中，远场光学不能获得材料中局域缺陷等对异质结构光响应和光电性能的影响。本项目拟通过结合近场光学和时间分辨光谱技术，研究局域缺陷或掺杂对二维材料异质结构的光学跃迁的影响；研究面内和层间激子行为，揭示局域缺陷等对光吸收以及激子产生、传输、复合过程的影响，有望对基于二维材料异质结构的光电器件的性能提高具有指导意义。

Two-dimensional (2D) materials and their van der Waals heterostructures have superior optical and electrical properties, and have great potential in future opto-electronic devices and energy conversion. In conventional optical and spectroscopic characterization, due to diffraction limit, far-field characterization can not resolve the influence of local defects and doping to the optical response of the heterostructures and their opto-electrical response. This proposal will combine near-field optical spectroscopy and time-resolved spectroscopic technique to study the effect of local defects to optical transitions, to study the interlayer and intralayer excitons, and reveal the effects to the optical absorption and the generation, diffusion and recombination of excitons. Such studies would be helpful for the improvement of future 2D materials based opto-electronic devices.