Simultaneous measurements of thermal conductivity and Seebeck coefficients of roughened nanowire arrays

J. S. Sadhu, T. Hongxiang, J. Ma, J. Kim, S. Sinha

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We report simultaneous measurements of thermal conductivity and Seebeck coefficient on array-scale silicon nanowires fabricated by metal assisted chemical etching. The measurements are conducted on the solid and the mesoporous nanowire arrays (NWAs) obtained from etching 1 ohm-cm and 0.002 ohm-cm Si substrates respectively. We demonstrate control on sidewall morphology and doping of the arrays that have an aspect ratio up to 20 and 30% areal coverage. We employ differential frequency-domain measurements, separately on the array and the corresponding substrate to obtain the temperature drop and Seebeck voltage contribution of the nanowire array. The technique is validated by measurements on bulk silicon across the resistivity 0.002-1 ohm-cm. The Seebeck measurements reveal quenching of the phonon drag in the nanowires in comparison to the bulk in the measured temperature range of 300 K- 500 K. The Seebeck coefficient shows a ∼18% decrease in the solid NWAs and ∼22% increase in the mesoporous NWAs at room temperature. The thermal conductivity is close to Casimir limit for the solid wires while it drops to ∼2.5 W/mK in the mesoporous nanowires.

Original languageEnglish (US)
Title of host publicationNanoscale Thermoelectrics 2012 - Materials and Transport Phenomena
Pages25-32
Number of pages8
DOIs
StatePublished - Dec 1 2012
Event2012 MRS Spring Meeting - San Francisco, CA, United States
Duration: Apr 9 2012Apr 13 2012

Publication series

NameMaterials Research Society Symposium Proceedings
Volume1456
ISSN (Print)0272-9172

Other

Other2012 MRS Spring Meeting
CountryUnited States
CitySan Francisco, CA
Period4/9/124/13/12

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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    Sadhu, J. S., Hongxiang, T., Ma, J., Kim, J., & Sinha, S. (2012). Simultaneous measurements of thermal conductivity and Seebeck coefficients of roughened nanowire arrays. In Nanoscale Thermoelectrics 2012 - Materials and Transport Phenomena (pp. 25-32). (Materials Research Society Symposium Proceedings; Vol. 1456). https://doi.org/10.1557/opl.2012.1371