Park, W., Ahn, E., Kodama, T., Park, J., Barako, M. T., Sohn, J., Cho, J., Kim, S., Marconnet, A. M., Asheghi, M., Sinclair, R., and Goodson, K. E., “Phonon Conduction in Silicon Nanobeam Labyrinths,” Scientific Reports, Vol. 7, article 6233.
Abstract
PDFHere we study single-crystalline silicon nanobeams having 470nm width and 80nm thickness cross section, where we produce tortuous thermal paths (i.e. labyrinths) by introducing slits to control the impact of the unobstructed “line-of-sight” (LOS) between the heat source and heat sink. The labyrinths range from straight nanobeams with a complete LOS along the entire length to nanobeams in which the LOS ranges from partially to entirely blocked by introducing slits, s=95, 195, 245, 295 and 395nm. The measured thermal conductivity of the samples decreases monotonically from ~47Wm−1K−1 for straight beam to ~31Wm−1K−1 for slit width of 395nm. A model prediction through a combination of the Boltzmann transport equation and ab inition calculations shows an excellent agreement with the experimental data to within ~8%. The model prediction for the most tortuous path (s=395nm) is reduced by ~14% compared to a straight beam of equivalent cross section. This study suggests that LOS is an important metric for characterizing and interpreting phonon propagation in nanostructures.
