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Download fileIdentifying the Manipulation of Individual Atomic-Scale Defects for Boosting Thermoelectric Performances in Artificially Controlled Bi2Te3 Films
journal contribution
posted on 08.03.2021, 14:41 authored by Min Zhang, Wei Liu, Cheng Zhang, Sen Xie, Zhi Li, Fuqiang Hua, Jiangfan Luo, Zhaohui Wang, Wei Wang, Fan Yan, Yu Cao, Yong Liu, Ziyu Wang, Ctirad Uher, Xinfeng TangThe
manipulation of individual intrinsic point defects is crucial
for boosting the thermoelectric performances of n-Bi2Te3-based thermoelectric films, but was not achieved in previous
studies. In this work, we realize the independent manipulation of
Te vacancies VTe and antisite defects of TeBi and BiTe in molecular beam epitaxially grown n-Bi2Te3 films, which is directly monitored by a scanning
tunneling microscope. By virtue of introducing dominant TeBi antisites, the n-Bi2Te3 film can achieve the
state-of-the-art thermoelectric power factor of 5.05 mW m–1 K–2, significantly superior to films containing
VTe and BiTe as dominant defects. Angle-resolved
photoemission spectroscopy and systematic transport studies have revealed
two detrimental effects regarding VTe and BiTe, which have not been discovered before: (1) The presence of BiTe antisites leads to a reduction of the carrier effective
mass in the conduction band; and (2) the intrinsic transformation
of VTe to BiTe during the film growth results
in a built-in electric field along the film thickness direction and
thus is not beneficial for the carrier mobility. This research is
instructive for further engineering defects and optimizing electronic
transport properties of n-Bi2Te3 and other technologically
important thermoelectric materials.
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V TeTe vacancies V TeBi Te antisitesscanning tunneling microscopeAngle-resolved photoemission spectr...n-Bi 2 Te 3 filmTe Bi antisitesBi Ten-Bi 2 Te 3film thickness directionn-Bi 2 Te 3 filmsBoosting Thermoelectric PerformancesArtificially Controlled Bi 2 Te 3 FilmsIndividual Atomic-Scale Defectsfilm growth results