基于界面电荷转移的关联荧光辐射行为的调控与表征

The diverse internal electronic motions are heart factors for semiconductor devices. Control of carrier transport (exchange) at low-dimensional semiconductor heterojunction interfaces, enables many unusual physical/chemical properties and observation of quantum phenomena. This project is motivated by the intriguing intermittent charge transfer behavior in weakly contacted 2D semiconductor heterojunctions with appropriate interfacial interactions. With the aid of light or an electrical filed, we will explore ways towards fine control on motions of electron/holes in both type I and type II heterostructures, and towards the realization of a series of novel phenomena related with dynamically correlated fluorescence emission, including switching of correlation sign, state-distribution control, “blinking” photo-current, or even acquisition of alternating photo-current signals. Meanwhile, we will develop a series of novel dynamic, multi-channel spectroscopy and optical imaging methods for further in-depth investigations. Through the above studies on acquisition, control and characterization of dynamically correlated fluorescence emission and blinking/alternating photo-current signals, we will have a better understanding on the general rules of carrier motions at 2D heterojunction interface, which helps to develop systematic strategies towards controllable carrier motions at nanoscale interface. Our study will provide new concepts for the design/development of novel semiconductor optoelectronic devices.

半导体器件的核心是其内部多样化的电子运动，控制低维半导体异质结界面的载流子传输（交换），可以实现诸多不同寻常的物理化学性质与量子现象。本项目从弱界面相互作用条件下二维发光材料单元间的间歇性界面电荷转移行为出发，利用光、电等外场手段对I型和II型二维异质结中电子和空穴传输行为进行精细调控，探索一系列新奇动态荧光辐射现象的可控实现方法，包括相关性符号、动态变化规律的调控以及动态光电流、交变光电流信号的获取等。在开展上述探索性研究同时，积极发展密切相关的动态、多通道的新型光谱学分析与光学成像方法。通过这些基于界面电荷转移的动态关联荧光信号、交变光电流信号的获取、调控与表征实验，我们将深入认识与理解二维异质结界面载流子运动规律，发展纳尺度界面载流子行为的系统调控方法，相关研究成果将为新型光电器件的设计与开发提供新思路。

认识与调控低维半导体异质结界面的载流子传输行为是实现诸多不同寻常的物理化学性质与量子现象的关键。本项目围绕二维半导体发光材料中界面载流子行为的调控、表征与功能开展了一系列原创性探索。通过项目的实施，我们取得了多方面的进展：1）发展了时空分辨的多点激发动态关联荧光成像技术；2）通过间隙结构WS2/WSe2二维异质结的精细构筑，观测到了半导体中的自发极性跳跃现象，并利用静电注入实现了对两组分涨落关联性的按需调控；3）通过构筑弱耦合状态电子给体—受体回路，直接捕获了二维异质结层间的闪烁光电流，并精确测量了涨落事件中流过界面的电荷量； 4）通过光、磁场和晶格应力实现了不同场景中激子发光与载流子输运行为的表征与可控调制。这些进展将为人们认识和理解二维异质结界面载流子运动规律，发展纳尺度界面载流子行为的系统调控方法以及新型光电器件的设计与开发提供新的途径和思路。项目实施以来共发表高水平学术论文7篇，获授权中国专利1项，作国内外学术会议邀请报告4次，培养博士毕业生1名，培养硕士毕业生1名。