二维材料热输运的反常基底效应研究

The research on the thermal transport mechanisms of two-dimensional materials has become a hot spot in the field of engineering thermophysics. Many two-dimensional materials exhibit superior thermal/electrical transport properties. However, no matter the experimental measurements or numerical simulations, the research on the thermal transport in two-dimensional materials mainly focuses on the suspended materials. Few studies have focused on the influence of the substrate on the thermal transport properties of two-dimensional materials. In the current research work, most researchers think that the substrates have only one effect on the thermal transport in the two-dimensional materials that they support, which generates strong phonon scattering in the two-dimensional materials so that the thermal conductivities of the two-dimensional materials are greatly reduced; our previous research results show that the presence of the substrate can not only reduce, but also improve the thermal conductivities of the two-dimensional materials, showing an abnormal substrate effect. The project uses 3-omega, time-domain thermoreflectance (TDTR) measurement methods, molecular dynamics simulations and first-principles calculations of the abnormal substrate effects on the thermal transport in supported two-dimensional materials and films to explore the effect of substrate type, substrate roughness, and external pressure on the thermal transport properties of two-dimensional materials and films and the mechanisms of phonon transport, which laid the foundation for the application of two-dimensional materials and films in the thermal management of electronic / optoelectronic devices.

二维材料热输运机理的研究已经成为当前工程热物理领域的研究热点，很多二维材料表现出了非常优异的热/电输运特性。然而目前，无论是实验测量还是数值模拟，对二维材料热输运的研究主要侧重于悬空材料，很少有研究关注基底对二维材料热输运性质的影响规律。现有的研究工作中，大多数学者认为基底对其所支撑的二维材料的热输运只有一种效应，就是会在二维材料中产生强烈的声子散射，从而使二维材料的热导率大大降低；而我们的前期研究结果表明，基底的存在不仅可以降低，也可以提高二维材料的热导率，呈现出反常的基底效应。本项目采用3-omega、时域热反射（TDTR）测量方法以及分子动力学模拟和第一性原理计算对这种二维材料热输运的反常基底效应进行研究，探索基底种类、基底粗糙度以及外界压力对二维材料和薄膜热输运性质的影响规律和声子输运机理，为二维材料和薄膜在电子/光电子器件热管理中的应用奠定基础。

二维材料热输运机理的研究已经成为当前工程热物理领域的研究热点，很多二维材料表现出了非常优异的热/电输运特性。然而目前，无论是实验测量还是数值模拟，对二维材料热输运的研究主要侧重于悬空材料，很少有研究关注基底对二维材料热输运性质的影响规律。本项目围绕二维材料和薄膜热输运特性的基底效应展开研究，通过分子动力学模拟和第一性原理计算，研究了基底种类（如Si，6H-SiC，3C-SiC等）对基底支撑的半导体材料（如立方III-V化合物BX（P，N，As，Sb））界面热输运的影响规律，并分析了层间作用力对双层石墨烯和石墨晶格热导率的影响规律，同时研究了外界压力、应力、外加电场、元素掺杂等调控手段对单层和双层五边形石墨烯、二维过渡金属二卤化物、二维Zintl相锑化镁、二维InSe等二维材料热和热电输运特性的影响规律。研究结果为二维材料和薄膜在光电子/电子器件热管理以及热电能源转换领域的广泛应用奠定了理论和实验基础。.在本项目资助下，共发表SCI论文15篇，发表学术会议论文2篇，参加国际会议报告4次，国内会议报告3次，培养博士毕业生和硕士毕业生各1名。