Thermoelectric conversion in disordered nanowires

Abstract : This thesis is focused on thermoelectric conversion in disordered semiconductor nanowires in the field effect transistor configuration. We first consider a low temperature regime, when electronic transport is elastic. For a 1D Anderson model, we derive analytical expressions describing the typical thermopower of a single nanowire as a function of the applied gate voltage, and we show that it is largely enhanced at the nanowire band edges. Our results are confirmed by numerical simulations based on a Recursive Green Function calculation of the thermopower. We then consider the case of inelastic transport, achieved by phonon-assisted hopping among localized states (Variable Range Hopping). By solving numerically the Miller Abrahams random resistor network, we show that the thermopower can attain huge values when the nanowire band edges are probed. A percolation theory by Zvyagin extended to nanowires allows to qualitatively describe our results. Also, the mechanism of heat exchange between electrons and phonons at the band edges lead to the generation of hot and cold spots near the boundaries of a substrate. This effect, of interest for cooling issues in microelectronics, is showed for a set of parallel nanowires, a scalable and hence promising system for practical applications. The power factor and figure of merit of the device are also estimated.Finally, we characterize a general three-terminal system within the linear response (Onsager) formalism: we derive local and non-local transport coefficients, as well as generalized figures of merit. The possibility of improving the performance of a generic quantum machine is discussed with the help of two simple examples.
Complete list of metadatas

Cited literature [186 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-01087448
Contributor : Riccardo Bosisio <>
Submitted on : Wednesday, November 26, 2014 - 11:33:44 AM
Last modification on : Thursday, February 7, 2019 - 1:32:20 AM
Long-term archiving on: Friday, February 27, 2015 - 11:05:49 AM

Identifiers

  • HAL Id : tel-01087448, version 1

Citation

Riccardo Bosisio. Thermoelectric conversion in disordered nanowires. Classical Physics [physics.class-ph]. Université Pierre et Marie Curie - Paris VI, 2014. English. ⟨NNT : 2014PA066212⟩. ⟨tel-01087448⟩

Share

Metrics

Record views

484

Files downloads

676