Dresden 2006 – scientific programme

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O: Oberflächenphysik

O 39: Nanostructures III

O 39.12: Talk

Thursday, March 30, 2006, 17:45–18:00, PHY C213

Thermal boundary conductance of solid-solid interfaces — •Boris Krenzer, Andreas Janzen, Anja Hanisch, Matthias Wielens, and Michael Horn-von Hoegen — Universität Duisburg-Essen, Fachbereich Physik, Lotharstr. 1, 47057 Duisburg

With decreasing size the thermal properties of nanoscale devices become more and more important. The thermal conductivity of such devices is drastically altered compared to simple heat diffusion given in bulk material. Especially the cross plane thermal conductivity in layered structures is determined by the thermal conductivity of the interface between the neighboring layers. The microscopic picture of this situation is that phonons only have a certain probability to cross the interface and carry energy from one material to the other. The most two basic models for the calculation of the phonon transmission probability are the acoustic mismatch model (AMM) and the diffusive mismatch model (DMM). For low temperatures when the dominant phonon wavelength is much larger than the interface roughness the AMM is used for the calculation. With increasing temperature the dominant phonon wavelength becomes comparable to the interface roughness and the transmission probability is calculated within the DMM. In the past the models explained the observed TBC at low temperatures but failed at higher temperatures where the experimental TBC was found to be orders of magnitude higher than the prediction. Recently we measured the TBC of the Bi/Si-interface which is in good agreement with the predictions. In this talk the AMM and DMM are presented in general and the results of the calculations will be applied to the Bi/Si-system.