Control of surface morphology and crystal structure of silicon nanowires and their coherent phonon transport characteristics
- Authors
- Lee, Seung-Yong; Kim, Gil-Sung; Lim, Jongwoo; Han, Seungwoo; Li, Baowen; Thong, John T. L.; Yoon, Young-Gui; Lee, Sang-Kwon
- Issue Date
- Feb-2014
- Publisher
- PERGAMON-ELSEVIER SCIENCE LTD
- Keywords
- Silicon nanowires; Thermal conductivity; Stacking fault; Phonon boundary scattering; Coherent phonon transport
- Citation
- ACTA MATERIALIA, v.64, pp 62 - 71
- Pages
- 10
- Journal Title
- ACTA MATERIALIA
- Volume
- 64
- Start Page
- 62
- End Page
- 71
- URI
- https://scholarworks.bwise.kr/cau/handle/2019.sw.cau/12534
- DOI
- 10.1016/j.actamat.2013.11.042
- ISSN
- 1359-6454
1873-2453
- Abstract
- We report on the first experimental observation of coherent phonon transport characteristics in silicon nanowires (SiNWs) synthesized by a one-step surface reconstruction growth mechanism. As-grown SiNWs taper down along the growth direction alongside a decrease in both roughness and stacking fault density. Furthermore, by systematically measuring the temperature-dependent thermal conductivity using a conventional thermal bridge method, we found that the measured thermal conductivity values of surface-reconstructed (SR)-SiNWs (13-20W m(-1) K-1) at room temperature are markedly lower than that predicted from the conventional diffuse phonon transport model for given NW diameters. We also observed that the thermal conductivities of SR-SiNWs exhibit an unexpected power law of similar to T-alpha (1.6 <= alpha <= 1.9) in the temperature range of 25-60 K, which cannot be explained by the typical similar to Debye T-3 behavior. Interestingly, our experimental results are consistent with a frequency-dependent model, which can be induced by coherence in the diffuse reflection and backscattering of phonons at the rough surface and stacking faults on SR-SiNWs, resulting in the suppressed thermal conductivity. Therefore, the demonstrated rational synthesis model and measurement technique promise great potential for improving the performance of a wide range of one-dimensional NW-based thermoelectric devices. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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Collections - College of Natural Sciences > Department of Physics > 1. Journal Articles
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