Thermal Conductance of Solid-Solid Interfaces

界面在控制纳米结构和纳米材料中的热传输方面起着关键作用，因为表面和界面限制了声子的平均自由程，而低的界面热导抑制了不同材料之间的能量传递。具有高密度内部界面的材料，如短周期超晶格和多层膜，以及纳米晶材料，显示出为热电和热障涂层提供低导热材料的前景。拟议工作的目标是通过阐明限制相似材料之间的热传输的机制以及在不同材料之间产生异常大的传输的机制来更好地理解界面的热导。该研究小组将研究TiN/MgO外延薄膜；H端面和清洁硅上的Ag外延薄膜；H端面金刚石上的Au和Pt薄膜；以及原子层沉积合成的W/Al_2O_3纳米层状物。这些实验将利用该团队在使用时间域热反射测量热物性方面的最新进展。这项工作中正在开发的实验方法也使改进的计量工具能够表征微尺度设备中的热传递。

Interfaces play a critical role in controlling heat transport in nanostructures and nanostructured materials because surfaces and interfaces limit the mean-free-path of phonons and low values of the interface thermal conductance inhibit the transfer of energy between dissimilar materials. Materials with high densities of internal interfaces-e.g., short period superlattices and multilayers, and nanocrystalline materials-show promise of providing low thermal conductivity materials for thermoelectrics and thermal barrier coatings. The goal of the proposed work is to establish a greater understanding of the thermal conductance of interfaces by elucidating the mechanisms that limit heat transport between similar materials and the mechanisms that produce anomalously large transport between dissimilar materials. The research team will study epitaxial films of TiN/MgO; Ag on H-terminated and clean Si; Au and Pt films on H-terminated diamond; and nanolaminates of W/Al2O3 synthesized by atomic-layer-deposition. These experiments will exploit the team's recent advances in thermal property measurement using time-domain thermoreflectance. The experimental methods being developed in this work are also enabling improved metrology tools for characterizing heat-transfer in microscale devices.