Science Daily December 21, 2021
Often the thermal energy generated in the device during operation must cross several dissimilar materials during the process and the interface between these materials can impede heat flow. An international team of researchers (Georgia Institute of Technology, University of Notre Dame, UC Irvine, US.S. Naval Research Laboratory, UCLA, Oak Ridge National Laboratory, South Korea) observed the interfacial phonon modes experimentally at a high-quality Si-Ge epitaxial interface by using Raman Spectroscopy and high-energy resolution electron energy-loss spectroscopy (EELS). To figure out the role of interfacial phonon modes in heat transfer at interfaces, they used time-domain thermoreflectance to determine the temperature-dependent thermal conductance across these interfaces. They also observed a clean additional peak when they measured the sample with Si-Ge interface, which was not observed when they measured a Si wafer and a Ge wafer with the same system. Interfacial modes and thermal boundary conductance were confined to the interfacial region as predicted by theory. The discovery opens new pathways for engineering thermal conductance at interfaces for electronics cooling and other applications where phonons are majority heat carriers at material interfaces…read more. Open Access TECHNICAL ARTICLEÂ
Raman detection of interfacial modes at the Si-Ge interface. Credit: Nature Communications volume 12, Article number: 6901 (2021