MEASURING PHONON MEAN FREE PATHS USING THERMAL CONDUCTIVITY SPECTROSCOPY
Austin J. Minnich
Size effects in heat conduction, which occur when phonon mean free paths (MFPs) are comparable to characteristic lengths, are being extensively explored in many nanoscale systems for energy applications. Knowledge of MFPs is essential to understanding size effects, yet MFPs are largely unknown for most materials. In this chapter we provide a comprehensive overview of thermal conductivity spectroscopy, a recently developed technique that allows the direct measurement of phonon MFPs over a wide range of materials and length scales. We first introduce the physical principle of the technique and how the measurement is performed and interpreted, and then describe several experimental implementations that have allowed MFP distributions to be measured over length scales spanning nearly three orders of magnitude in silicon, gallium arsenide, and sapphire. Finally, we discuss how this newly developed technique may be applied over a much wider range of materials and length scales, as well as how the measurements can be used in the nanoscale heat transfer field and for energy applications.
|Portal Digitalde||Biblioteca Digital||eLibros||Revistas||Referencias y Libros de Ponencias||Colecciones|