金属半导体超晶格热离子发射制冷器通过热电子过滤原理可以潜在地提高固态制冷器的性能系数，在热管理和能源转化方面具有广泛的应用前景。本项目将结合理论分析和实验测试，探讨金属半导体Al/GaN界面，电子、声子对界面热传递的贡献，以及声子非弹性散射对界面热阻的影响。另外，通过对Si/Ge超晶格结构热导率的理论计算，本项目将给出超晶格周期长度与声子群速度和声子平均自由程的关系。本项目还将使用飞秒激光TDTR技术对金属基氮化物超晶格TiN/GaN结构的热导率进行测量。同已有文献相比，本项目考虑了电子—声子耦合效应，并能单独定量分析非弹性声子散射对界面热阻的影响，可以在原子尺度分析不同频率、不同波长声子对热导率的贡献。这些研究工作将为金属半导体超晶格热离子发射制冷器的设计和优化提供指导作用。

Thermionic refrigerator based on metal-semiconductor superlattices can improve the figure of merit potentially by hot electron filter, and have a wide range of applications in thermal management and energy conversion. The present project will investigate the interfacial thermal conductance of electron and phonon between Al and GaN, as well as the effects of inelastic scattering to interfacial thermal resistance. In addition, by calculating the thermal conductivity of Si/Ge superlattice, we will build a relation between the superlattice period length and the phonon group velocity and mean free path. We will also measure the thermal conductivity of TiN/GaN using TDTR technique based on femtosecond laser. Compared with the existing literature, the present project considers the electron-phonon coupling and the inelastic scattering effects, and can give a detail contribution of phonon with different frequency and wavelengths to thermal conduction. These investigations will provide guidance to the design and optimization of thermionic refrigerator based on metal-semiconductor superlattices.