Thermoelectric properties of highly doped n-type polysilicon inverse opals

Jun Ma, Sanjiv Sinha

Research output: Contribution to journalArticlepeer-review

Abstract

Nanostructured single-crystal silicon exhibits a remarkable increase in the figure of merit for thermoelectric energy conversion. Here we theoretically investigate a similar enhancement for polycrystalline silicon inverse opals. An inverse opal provides nanoscale grains and a thin-film like geometry to scatter phonons preferentially over electrons. Using solutions to the Boltzmann transport equation for electrons and phonons, we show that the figure of merit at 300 K is fifteen times that of bulk single-crystal silicon. Our models predict that grain boundaries are more effective than surfaces in enhancing the figure of merit. We provide insight into this effect and show that preserving a grain size smaller than the shell thickness of the inverse opal increases the figure of merit by as much as 50% when the ratio between the two features is a third. At 600 K, the figure of merit is as high as 0.6 for a shell thickness of 10 nm. This work advances the fundamental understanding of charge and heat transport in nanostructured inverse opals.

Original languageEnglish (US)
Article number073719
JournalJournal of Applied Physics
Volume112
Issue number7
DOIs
StatePublished - Oct 1 2012

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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