Thermal conductivity of silicon nanowire arrays with controlled roughness

Joseph P. Feser, Jyothi S. Sadhu, Bruno P. Azeredo, Keng H. Hsu, Jun Ma, Junhwan Kim, Myunghoon Seong, Nicholas X. Fang, Xiuling Li, Placid M. Ferreira, Sanjiv Sinha, David G. Cahill

Research output: Contribution to journalArticle

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.

Original languageEnglish (US)
Article number114306
JournalJournal of Applied Physics
Volume112
Issue number11
DOIs
StatePublished - Dec 1 2012

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Thermal conductivity of silicon nanowire arrays with controlled roughness'. Together they form a unique fingerprint.

  • Cite this

    Feser, J. P., Sadhu, J. S., Azeredo, B. P., Hsu, K. H., Ma, J., Kim, J., Seong, M., Fang, N. X., Li, X., Ferreira, P. M., Sinha, S., & Cahill, D. G. (2012). Thermal conductivity of silicon nanowire arrays with controlled roughness. Journal of Applied Physics, 112(11), [114306]. https://doi.org/10.1063/1.4767456