二硫化钼-石墨烯异质结界面物理及其压电调控研究

Recently, the heterostructures formed by the stacking of 2-dimensional materials through weak van der Waal (VDW) forces draw intensive attention. A typical representative is MoS2/graphene VDW heterojunction, which effectively combines the excellent optical-electrical characteristic of MoS2 and the high in-plane carrier mobility of graphene. Fruitful research on the electronic structures and photoelectric conversion of MoS2/graphene heterojunction have been carried out, while there is enormous blank in the study on the thermal and mechanical properties of the interface. This project aims to carry out a series of experimental studies on the interfacial thermal transport, electrical transport and mechanical coupling of the heterojunction, and measure the actual parameters of interface physics. The mechanism of interfacial heat transfer and its potential regulation methods will be explored, the influence of charge tunneling at the interface on thermal transport is going to be analyzed, and the possible modulation on heat transfer in heterojunction of piezoelectric effect of MoS2 will be investigated. The influence of VDW interaction on interlaminar slip and shear deformation is going to be clarified. We will discuss the correlation and transformation mechanism among the thermal, mechanical, electrical and piezoelectric properties of the heterojunction, and construct a comprehensive theoretical image for the physical properties of the heterojunction, which will lay a solid experimental and theoretical foundation for the application of the heterojunction in new thermoelectric, piezoelectric and flexible sensing devices, and provide a rich theoretical reference for the study of similar heterostructures.

近年来，由不同二维材料依靠原子间微弱的范德华力堆叠而成的异质结构受到了广泛的关注，二硫化钼-石墨烯范德华异质结则是其中的典型代表。该异质结有效结合了二硫化钼优异的光电特性和石墨烯超高的面内载流子迁移率。国内外针对二硫化钼-石墨烯异质结的电子结构和光电转化开展了卓有成效的研究。然而，对其界面热学、力学特性的研究还亟待深入。本项目拟针对该异质结的界面热导、电导、力学耦合开展系列实验研究，测量得到其各物理特性的实际参数；探明界面热传输机制及其潜在调控方法，分析电荷在界面的隧穿传输对热导的影响，探究二硫化钼的压电效应对异质结热传输的可能调控作用；明晰范德华相互作用对异质结层间滑动和剪切形变的影响；探讨该异质结的热、力、电和压电特性的相互关联和转化机制，构建该异质结物理特性的完整理论图像，为其在新型热电、压电和柔性传感器件中的应用打下坚实的实验和理论基础，为同类异质结构的研究提供丰富的理论参考。

二硫化钼和石墨烯是二维材料的典型代表，由二者构成的范德华异质结，由于继承了二者的优点，更是受到了广泛关注。为构筑该异质结构物理特性的完整图像，本项目针对其界面热导、界面力学耦合、电荷传输及其力热电特性相互转化机制展开了系统研究。代表性结果如下：1）利用微加工工艺和显微操控技术，实现了不同类型衬底上异质结及器件的高效制备；2）通过变温拉曼和光热拉曼技术，测量了异质结界面热导，结合晶体管电学调控，揭示了界面热导的电学可控性，分析并提出电子输运对界面热导的影响；3)通过对异质结的力电响应、光电响应、热释电效应及电学特性的光、力同步调控等的测试，从界面势垒、界面耦合等微观层面分析了异质结热、电、力特性的相互关联；4)设计制备了多种以二维材料及其异质结构为基础的高性能光电、力电、温度和气体传感器，为其实际应用打下了理论和技术基础。本项目的研究揭示了二维范德华异质结体系的热导新机制，进一步阐明了二硫化钼-石墨烯异质结界面原子、电子相互作用对其界面热、力、电等特性的影响，为其在热电器件、柔性电子和微纳机电系统中的应用提供了理论参考。