Enhancement of the electronic thermoelectric properties of bulk strained silicon-germanium alloys using the scattering relaxation times from first principles calculations

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dc.contributor.author Murphy-Armando, Felipe
dc.date.accessioned 2019-12-20T09:58:52Z
dc.date.available 2019-12-20T09:58:52Z
dc.date.issued 2019-12-02
dc.identifier.citation Murphy-Armando, F. (2019) ‘Enhancement of the electronic thermoelectric properties of bulk strained silicon-germanium alloys using the scattering relaxation times from first principles calculations’, Journal of Applied Physics, 126, 215103 (9pp). doi: 10.1063/1.5117345 en
dc.identifier.volume 126 en
dc.identifier.startpage 1 en
dc.identifier.endpage 9 en
dc.identifier.issn 0021-8979
dc.identifier.uri http://hdl.handle.net/10468/9439
dc.identifier.doi 10.1063/1.5117345 en
dc.description.abstract We use first-principles electronic structure methods to calculate the electronic thermoelectric properties (i.e., due to electronic transport only) of single-crystalline bulk n-type silicon-germanium alloys vs Ge composition, temperature, doping concentration, and strain. We find excellent agreement to available experiments for the resistivity, mobility, and Seebeck coefficient. These results are combined with the experimental lattice thermal conductivity to calculate the thermoelectric figure of merit ZT, finding very good agreement with experiments. We predict that 3% tensile hydrostatic strain enhances the n-type ZT by 50% at carrier concentrations of n=1020cm−3 and a temperature of T=1200K. These enhancements occur at different alloy compositions due to different effects: at 50% Ge composition, the enhancements are achieved by a strain induced decrease in the Lorenz number, while the power factor remains unchanged. These characteristics are important for highly doped and high temperature materials, in which up to 50% of the heat is carried by electrons. At 70% Ge, the increase in ZT is due to a large increase in the electrical conductivity produced by populating the high mobility Γ conduction band valley, lowered in energy by strain. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher AIP Publishing en
dc.rights © 2019, the Author. Published under license by AIP Publishing. This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. This article appeared as: Murphy-Armando, F. (2019) ‘Enhancement of the electronic thermoelectric properties of bulk strained silicon-germanium alloys using the scattering relaxation times from first principles calculations’, Journal of Applied Physics, 126, 215103 (9pp), doi: 10.1063/1.5117345, and may be found at https://doi.org/10.1063/1.5117345 en
dc.subject Electronic thermoelectric properties en
dc.subject Single-crystalline bulk n-type silicon-germanium alloys en
dc.subject Ge composition en
dc.subject Temperature en
dc.subject Doping concentration en
dc.subject Strain en
dc.subject Resistivity en
dc.subject Mobility en
dc.subject Seebeck coefficient en
dc.title Enhancement of the electronic thermoelectric properties of bulk strained silicon-germanium alloys using the scattering relaxation times from first principles calculations en
dc.type Article (peer-reviewed) en
dc.internal.authorcontactother Felipe Murphy-Armando, Tyndall National Institute, University College Cork, Cork, Ireland. T: +353-21-490-3000 E: philip.murphy@tyndall.ie en
dc.internal.availability Full text available en
dc.check.info Access to this article is restricted until 12 months after publication by request of the publisher. en
dc.check.date 2020-12-02
dc.description.version Published Version en
dc.contributor.funder Science Foundation Ireland en
dc.description.status Peer reviewed en
dc.identifier.journaltitle Journal of Applied Physics en
dc.internal.IRISemailaddress philip.murphy@tyndall.ie en
dc.identifier.articleid 215103 en
dc.relation.project info:eu-repo/grantAgreement/SFI/SFI Investigator Programme/12/IA/1601/IE/Ultrafast energy dissipation in semimetals and semiconductors: Simulation based on first-principles electronic structure theory/ en
dc.identifier.eissn 1089-7550


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