Low Temperature Enhancement of the Thermoelectric Seebeck Coefficient in Semiconductor Nanoribbons

By Kommini Adithya1, Zlatan Aksamija1

1. Electrical and Computer Engineering, University of Massachusetts Amherst, Amherst, MA

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Abstract

<a href="/groups/iwce2015">IWCE 2015</a> Presentation. An increasing need for effective thermal sensors, together with dwindling energy resources, have created renewed interests in thermoelectric (TE), or solid-state, energy conversion and refrigeration using semiconductor based nanostructures. Effective control of electron and phonon transport due to confinement, interface, and quantum effects has made nanostructures a good way to achieve more efficient thermoelectric energy conversion. Theoretically, a narrow delta-function shaped transport distribution function (TDF) is believed to provide the highest Seebeck coefficient, but has proven difficult to achieve in practice. We propose a novel approach to achieving a narrow window-shaped TDF through a combination of a step-like 2-dimensional density-of-states (DOS) and inelastic optical phonon scattering. A shift in the onset of scattering with respect to the step-like DOS creates a TDF which peaks over a narrow band of energies. We perform a numerical simulation of carrier transport in silicon nanoribbons based on numerically solving the coupled Schrödinger-Poisson equations together with transport in the semi-classical Boltzmann formalism. Our calculations confirm that inelastic scattering of electrons, combined with the step-like DOS in 2-dimensional nanostructures leads to the formation of a narrow window-function shaped TDF and results in enhancement of Seebeck coefficient beyond what was already achieved through confinement alone. A further analysis on maximizing this enhancement by tuning the material properties is also presented.

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Cite this work

Researchers should cite this work as follows:

  • A. Kommini, Z. Aksamija, Low Temperature Enhancement of the Thermoelectric Seebeck Coefficient in Semiconductor Nanoribbons, 2015 International Workshop on Computational Electronics (IWCE), West Lafayette, IN, 2015.

  • Kommini Adithya; Zlatan Aksamija (2016), "Low Temperature Enhancement of the Thermoelectric Seebeck Coefficient in Semiconductor Nanoribbons," https://nanohub.org/resources/25139.

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North Ballroom, PMU, Purdue University, West Lafayette, IN

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