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递中起着至关重要的作用，因为表面和界面限制了声子的平均自由程，而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。短周期超晶格和多层，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希望。所提出的工作的目标是通过阐明限制类似材料之间热传递的机制和在不同材料之间产生异常大传输的机制，建立对界面导热性的更好理解。本课题组将研究TiN/MgO外延薄膜；银端h和清洁Si；h端金刚石上的Au和Pt薄膜原子层沉积法制备W/Al2O3纳米层合材料。这些实验将利用该团队在使用时域热反射测量热性能方面的最新进展。在这项工作中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.