Phonon Conduction in Silicon Nanobeam Labyrinths.

ABSTRACT: Here we study single-crystalline silicon nanobeams having 470?nm width and 80?nm 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 395?nm. The measured thermal conductivity of the samples decreases monotonically from ~47?W?m-1?K-1 for straight beam to ~31?W?m-1?K-1 for slit width of 395?nm. A model prediction through a combination of the Boltzmann transport equation and ab initio calculations shows an excellent agreement with the experimental data to within ~8%. The model prediction for the most tortuous path (s?=?395?nm) 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.

SUBMITTER: Park W 

PROVIDER: S-EPMC5524879 | biostudies-other | 2017 Jul

REPOSITORIES: biostudies-other