Thermal Conductance of Solid-Solid Interfaces

界面在控制纳米结构和纳米结构材料中的热传输中起着关键作用，因为表面和界面限制了声子的平均自由程，并且界面热导的低值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-例如，短周期超晶格和多层以及纳米晶体材料显示出为热电和热障涂层提供低导热率材料的前景。拟议的工作的目标是建立一个更好的理解界面的热导，阐明了机制，限制类似材料之间的热传输和机制，产生巨大的不同材料之间的运输。该研究小组将研究TiN/MgO外延膜;在H端和清洁Si上的Ag;在H端金刚石上的Au和Pt膜;以及通过原子层沉积合成的W/Al 2 O3纳米层压材料。这些实验将利用该团队最近在使用时域热反射测量热性能方面的进展。在这项工作中开发的实验方法也使改进的计量工具，用于表征微尺度器件中的传热。

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.