Semimetal to semiconductor transition in Bi/TiO2 core/shell nanowires

Abstract: We demonstrate the full thermoelectric and structural characterization of individual bismuth-based (Bi-based) core/shell nanowires. The influence of strain on the temperature dependence of the electrical conductivity, the absolute Seebeck coefficient and the thermal conductivity of bismuth/titanium dioxide (Bi/TiO2) nanowires with different diameters is investigated and compared to bismuth (Bi) and bismuth/tellurium (Bi/Te) nanowires and bismuth bulk. Scattering at surfaces, crystal defects and interfaces between the core and the shell reduces the electrical conductivity to less than 5% and the thermal conductivity to less than 25% to 50% of the bulk value at room temperature. On behalf of a compressive strain, Bi/TiO2 core/shell nanowires show a decreasing electrical conductivity with decreasing temperature opposed to that of Bi and Bi/Te nanowires. We find that the compressive strain induced by the TiO2 shell can lead to a band opening of bismuth increasing the absolute Seebeck coefficient by 10% to 30% compared to bulk at room temperature. In the semiconducting state, the activation energy is determined to |41.3 ± 0.2| meV. We show that if the strain exceeds the elastic limit the semimetallic state is recovered due to the lattice relaxation

Location
Deutsche Nationalbibliothek Frankfurt am Main
Extent
Online-Ressource
Language
Englisch
Notes
Nanoscale advances. - 3, 1 (2021) , 263-271, ISSN: 2516-0230

Event
Veröffentlichung
(where)
Freiburg
(who)
Universität
(when)
2021
Creator
Kockert, Maximilian
Mitdank, Rüdiger
Moon, Hongjae
Kim, Jeongmin
Mogilatenko, Anna
Moosavi, Seyedeh Hoda
Kröner, Michael
Woias, Peter
Lee, Wooyoung
Fischer, Saskia F.

DOI
10.1039/d0na00658k
URN
urn:nbn:de:bsz:25-freidok-2187493
Rights
Kein Open Access; Der Zugriff auf das Objekt ist unbeschränkt möglich.
Last update
25.03.2025, 1:41 PM CET

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Associated

Time of origin

  • 2021

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