范德瓦尔斯异质结中界面电荷转移的超快光学研究

项目名称： 范德瓦尔斯异质结中界面电荷转移的超快光学研究

项目编号： No.11504062

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 王瑞

作者单位： 国家纳米科学中心

项目金额： 24万元

中文摘要： 由二维层状材料堆叠形成的范德瓦尔斯异质结在新型半导体器件领域有着广泛的应用前景，如场效应隧穿晶体管、光伏器件等。该类器件的关键性能往往取决于单原子层（或少层）材料的界面电子态结构和电荷转移过程。然而目前的研究工作大多关注于器件的宏观电学输运，对界面能带的耦合及载流子动力学过程认识有限。在此申请项目中，我们拟利用超快时间分辨动力学技术研究发生在这类原子层晶体异质结界面的载流子的能量和动量弛豫过程，利用光激发跃迁探测处于范德瓦尔斯异质结界面的能级和电子态结构，从而揭示几种典型范德瓦尔斯异质结器件电荷转移的微观机制，为二维层状材料异质结器件的制备和性能提升提供实验和理论依据。

中文关键词： 范德瓦尔斯异质结；界面电荷转移；超快动力学

英文摘要： Two dimensional layered (2D) materials, such as graphene, and transition metal dichalcogenides (TMDs), have sparked wide interest in both device physics and technological application at the atomic monolayer limit. These 2D monolayer can be stacked together vertically with precise control to form novel van der Waals heterostructure for new functionalities. Such a concept has already proved fruitful for a number of optoelectronic and photoactive applications in the area of ultrathin devices, such as photovoltaic and field effect tunneling transistor. So far, most studies focus on electronic measurement, which just provide total effect, not include carrier dynamics and band structure information. Hence, in order to fully understand why and how charge carrier transfer happens in heterostructure, it is very necessary to study charge transfer by using ultrafast pump-probe technique. Through this technique, we can obtain carrier relaxation in energy and momentum. Based on our experiment, we can explain how to prepare better device and how to improve the performance of devices which are based on van der Waals heterostructure theoretically and experimentally.

英文关键词： van der Waals heterostructure;interface charge transfer;ultrafast dynamics