A microprobe technique for simultaneously measuring thermal conductivity and Seebeck coefficient of thin films

Yanliang Zhang, Claudiu L. Hapenciuc, Eduardo E. Castillo, Theodorian Borca-Tasciuc, Rutvik J. Mehta, Chinnathambi Karthik, Ganpati Ramanath

Research output: Contribution to journalArticlepeer-review

67 Scopus citations

Abstract

We demonstrate a microprobe technique that can simultaneously measure thermal conductivity κ and Seebeck coefficient α of thin films. In this technique, an alternative current joule-heated V-shaped microwire that serves as heater, thermometer and voltage electrode, locally heats the thin film when contacted with the surface. The κ is extracted from the thermal resistance of the microprobe and α from the Seebeck voltage measured between the probe and unheated regions of the film by modeling heat transfer in the probe, sample and their contact area, and by calibrations with standard reference samples. Application of the technique on sulfur-doped porous Bi 2 Te3 and Bi2 Se3 films reveals α=-105.4 and 1.96 μV/K, respectively, which are within 2% of the values obtained by independent measurements carried out using microfabricated test structures. The respective κ values are 0.36 and 0.52 W/mK, which are significantly lower than the bulk values due to film porosity, and are consistent with effective media theory. The dominance of air conduction at the probe-sample contact area determines the microscale spatial resolution of the technique and allows probing samples with rough surfaces.

Original languageEnglish
Article number062107
JournalApplied Physics Letters
Volume96
Issue number6
DOIs
StatePublished - 2010
Externally publishedYes

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