Thermopower enhancement in nanowires via junction effects

Nicolas B. Duarte, Gerald D. Mahan, Srinivas Tadigadapa

Research output: Contribution to journalArticle

22 Citations (Scopus)

Abstract

We present thermopower measurements on free-standing, straight and "junctioned" gold nanowires using a micromachined thermoelectric workbench. Measurements on straight 70 nm diameter gold nanowires show a thermopower similar to that of bulk gold; however for "junctioned" gold nanowires we observed a hitherto unreported peak in the thermopower near room temperature. The observed enhancement can be explained by approximating the "junctioned" nanowires as tunnel junctions in combination with Coulombic effect of the electrons crossing the junction. The electron transfer across the barrier can be expected to be stochastic in nature. Under thermal equilibrium conditions and in the absence of temperature gradient across the tunnel junction, the time averaged random fluctuation of the electrons across the tunnel junction results in a net zero voltage. However, in the presence of a temperature gradient across the junction, the time averaged fluctuation of the electrons across the junction is now offset by the tunnel junction thermoelectric effect and is measured by the lock-in amplifier. A hundredfold enhancement in the ZT of "junctioned" nanowires has been observed for the gold nanowires measured over several samples.

Original languageEnglish (US)
Pages (from-to)617-622
Number of pages6
JournalNano letters
Volume9
Issue number2
DOIs
StatePublished - Feb 11 2009

Fingerprint

Thermoelectric power
Nanowires
nanowires
Gold
Tunnel junctions
tunnel junctions
augmentation
gold
Electrons
Thermal gradients
temperature gradients
Thermoelectricity
electrons
electron transfer
amplifiers
Electric potential
electric potential
room temperature

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

Cite this

Duarte, N. B., Mahan, G. D., & Tadigadapa, S. (2009). Thermopower enhancement in nanowires via junction effects. Nano letters, 9(2), 617-622. https://doi.org/10.1021/n1802882h
Duarte, Nicolas B. ; Mahan, Gerald D. ; Tadigadapa, Srinivas. / Thermopower enhancement in nanowires via junction effects. In: Nano letters. 2009 ; Vol. 9, No. 2. pp. 617-622.
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Duarte, NB, Mahan, GD & Tadigadapa, S 2009, 'Thermopower enhancement in nanowires via junction effects', Nano letters, vol. 9, no. 2, pp. 617-622. https://doi.org/10.1021/n1802882h

Thermopower enhancement in nanowires via junction effects. / Duarte, Nicolas B.; Mahan, Gerald D.; Tadigadapa, Srinivas.

In: Nano letters, Vol. 9, No. 2, 11.02.2009, p. 617-622.

Research output: Contribution to journalArticle

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