Anufriev Roman, Gluchko Sergei, Volz Sebastian, Nomura Masahiro
Institute of Industrial Science, The University of Tokyo, Tokyo 153-8505, Japan.
Nanoscale. 2019 Jul 28;11(28):13407-13414. doi: 10.1039/c9nr03863a. Epub 2019 Jul 5.
Ballistic heat conduction in semiconductors is a remarkable but controversial nanoscale phenomenon, which implies that nanostructures can conduct thermal energy without dissipation. Here, we experimentally probed ballistic thermal transport at distances of 400-800 nm and temperatures of 4-250 K. Measuring thermal properties of straight and serpentine silicon nanowires, we found that at 4 K heat conduction is quasi-ballistic with stronger ballisticity at shorter length scales. As we increased the temperature, quasi-ballistic heat conduction weakened and gradually turned into diffusive regime at temperatures above 150 K. Our Monte Carlo simulations illustrate how this transition is driven by different scattering processes and linked to the surface roughness and the temperature. These results demonstrate the length and temperature limits of quasi-ballistic heat conduction in silicon nanostructures, knowledge of which is essential for thermal management in microelectronics.
半导体中的弹道热传导是一种显著但颇具争议的纳米尺度现象，这意味着纳米结构能够在无热耗散的情况下传导热能。在此，我们通过实验探究了在400 - 800纳米距离以及4 - 250开尔文温度下的弹道热输运。通过测量直的和蜿蜒的硅纳米线的热性质，我们发现，在4开尔文时热传导为准弹道式，且在较短长度尺度下弹道性更强。随着温度升高，准弹道热传导减弱，并在温度高于150开尔文时逐渐转变为扩散模式。我们的蒙特卡罗模拟展示了这种转变是如何由不同散射过程驱动的，以及如何与表面粗糙度和温度相关联。这些结果表明了硅纳米结构中准弹道热传导的长度和温度极限，了解这些对于微电子学中的热管理至关重要。
