Thermoelectric properties of highly doped n-type polysilicon inverse opals
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. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4758382]
- Sponsoring Organization:
- USDOE Advanced Research Projects Agency - Energy (ARPA-E)
- DOE Contract Number:
- DE-AR0000041PF-ARRA
- OSTI ID:
- 1211314
- Journal Information:
- Journal of Applied Physics, Vol. 112, Issue 7; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Area of contact and thermal transport across transfer-printed metal-dielectric interfaces
First-principles simulation of electron mean-free-path spectra and thermoelectric properties in silicon