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Title: Thermal conductivity of silicon nanowire arrays with controlled roughness

Abstract

A two-step metal assisted chemical etching technique is used to systematically vary the sidewall roughness of Si nanowires in vertically aligned arrays. The thermal conductivities of nanowire arrays are studied using time domain thermoreflectance and compared to their high-resolution transmission electron microscopy determined roughness. The thermal conductivity of nanowires with small roughness is close to a theoretical prediction based on an upper limit of the mean-free-paths of phonons given by the nanowire diameter. The thermal conductivity of nanowires with large roughness is found to be significantly below this prediction. Raman spectroscopy reveals that nanowires with large roughness also display significant broadening of the one-phonon peak; the broadening correlates well with the reduction in thermal conductivity. The origin of this broadening is not yet understood, as it is inconsistent with phonon confinement models, but could derive from microstructural changes that affect both the optical phonons observed in Raman scattering and the acoustic phonons that are important for heat conduction. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767456]

Authors:
; ; ; ; ; ; ; ; ; ; ;
Publication Date:
Sponsoring Org.:
USDOE Advanced Research Projects Agency - Energy (ARPA-E)
OSTI Identifier:
1211316
DOE Contract Number:  
DE-AR0000041PF-ARRA
Resource Type:
Journal Article
Journal Name:
Journal of Applied Physics
Additional Journal Information:
Journal Volume: 112; Journal Issue: 11; Journal ID: ISSN 0021-8979
Country of Publication:
United States
Language:
English

Citation Formats

Feser, JP, Sadhu, JS, Azeredo, BP, Hsu, KH, Ma, J, Kim, J, Seong, M, Fang, NX, Li, XL, Ferreira, PM, Sinha, S, and Cahill, DG. Thermal conductivity of silicon nanowire arrays with controlled roughness. United States: N. p., 2012. Web. doi:10.1063/1.4767456.
Feser, JP, Sadhu, JS, Azeredo, BP, Hsu, KH, Ma, J, Kim, J, Seong, M, Fang, NX, Li, XL, Ferreira, PM, Sinha, S, & Cahill, DG. Thermal conductivity of silicon nanowire arrays with controlled roughness. United States. https://doi.org/10.1063/1.4767456
Feser, JP, Sadhu, JS, Azeredo, BP, Hsu, KH, Ma, J, Kim, J, Seong, M, Fang, NX, Li, XL, Ferreira, PM, Sinha, S, and Cahill, DG. 2012. "Thermal conductivity of silicon nanowire arrays with controlled roughness". United States. https://doi.org/10.1063/1.4767456.
@article{osti_1211316,
title = {Thermal conductivity of silicon nanowire arrays with controlled roughness},
author = {Feser, JP and Sadhu, JS and Azeredo, BP and Hsu, KH and Ma, J and Kim, J and Seong, M and Fang, NX and Li, XL and Ferreira, PM and Sinha, S and Cahill, DG},
abstractNote = {A two-step metal assisted chemical etching technique is used to systematically vary the sidewall roughness of Si nanowires in vertically aligned arrays. The thermal conductivities of nanowire arrays are studied using time domain thermoreflectance and compared to their high-resolution transmission electron microscopy determined roughness. The thermal conductivity of nanowires with small roughness is close to a theoretical prediction based on an upper limit of the mean-free-paths of phonons given by the nanowire diameter. The thermal conductivity of nanowires with large roughness is found to be significantly below this prediction. Raman spectroscopy reveals that nanowires with large roughness also display significant broadening of the one-phonon peak; the broadening correlates well with the reduction in thermal conductivity. The origin of this broadening is not yet understood, as it is inconsistent with phonon confinement models, but could derive from microstructural changes that affect both the optical phonons observed in Raman scattering and the acoustic phonons that are important for heat conduction. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4767456]},
doi = {10.1063/1.4767456},
url = {https://www.osti.gov/biblio/1211316}, journal = {Journal of Applied Physics},
issn = {0021-8979},
number = 11,
volume = 112,
place = {United States},
year = {Sat Dec 01 00:00:00 EST 2012},
month = {Sat Dec 01 00:00:00 EST 2012}
}