Determining phonon mean free path spectrum by ballistic phonon resistance within a nanoslot-patterned thin film
Determining phonon mean free path spectrum by ballistic phonon resistance within a nanoslot-patterned thin film
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DOI：
10.1016/j.mtphys.2019.100126
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发表时间：
2019-08-01
影响因子：
11.5
通讯作者：
Chen, Q.
中科院分区：
文献类型：
--
作者：
Hao, Q.;Xiao, Y.;Chen, Q.
在微尺度到纳米尺度上，热传导中的经典尺寸效应在抑制热传输过程中起着重要的作用。当特征长度与热载流子(主要是非金属晶体的声子)的平均自由程(MFP)相称时，就会产生这种效应。除了现有的激光诱导热栅薄膜的实验工作外，本工作还为提取薄膜或片状样品面内热传导的有效声子MFP分布提供了理论分析。在这种方法中，纳米槽是在悬浮的薄膜上形成图案的。如果声子MFP远大于颈部宽度，则声子将以弹道方式通过相邻纳米槽之间的颈部区域。相关的不同颈部尺寸的“弹道热阻”可以用来重建薄膜内的声子MFP分布。当松弛时间近似相当准确时，该技术可以进一步扩展到二维材料。(C)2019爱思唯尔有限公司。保留所有权利。
At microscales to nanoscales, classical size effects in heat conduction play an important role in suppressing the thermal transport process. Such effects occur when the characteristic lengths become commensurate to the mean free paths (MFPs) of heat carriers that are mainly phonons for non-metallic crystals. Beyond existing experimental efforts on thin films using laser-induced thermal gratings, this work provides the theoretical analysis for a new approach to extract the effective phonon MFP distribution for the in-plane heat conduction within a thin film or flake-like sample. In this approach, nanoslots are patterned on a suspended thin film. Phonons will transport ballistically through the neck region between adjacent nanoslots if the phonon MFPs are much longer than the neck width. The associated 'ballistic thermal resistance' for varied neck dimensions can then be used to reconstruct the phonon MFP distribution within the film. The technique can be further extended to two-dimensional materials when the relaxation time approximation is reasonably accurate. (C) 2019 Elsevier Ltd. All rights reserved.