High temperature Z-meter setup for characterizing thermoelectric material under large temperature gradient

R Amatya; P M Mayer; R J Ram

doi:10.1063/1.4731650

High temperature Z-meter setup for characterizing thermoelectric material under large temperature gradient

Rev Sci Instrum. 2012 Jul;83(7):075117. doi: 10.1063/1.4731650.

Authors

R Amatya¹, P M Mayer, R J Ram

Affiliation

¹ Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, Massachusetts 02139, USA. ramatya@mit.edu

PMID: 22852734
DOI: 10.1063/1.4731650

Abstract

To properly estimate a thermoelectric material's performance, one should be able to characterize a single thermoelectric (TE) element with a large temperature gradient. In this work, we present an experimental setup including a Z-meter that can heat the sample to a very high temperature of 1200 °C in vacuum. The Z-meter can simultaneously measure all three thermoelectric parameters (Seebeck coefficient, thermal conductivity, and electrical conductivity), as well as measure the generated power and the efficiency for a single TE leg. Furthermore, this measurement of power conversion efficiency is used to generate a measure of the material's ZT. An in situ metallurgical bond was used to achieve low thermal (0.05 Kcm(2)/W) and electrical (3 mΩ) contact parasitics. An integrated strain gauge ensures reproducible thermal contact. At high temperature (>600 K), radiative heat transfer is modeled and the instrument is optimized to suppress the systematic error to below 7%. The TE parameters and ZT for a bulk-sample (Bi(2)Te(3)) and a thin-film sample (ErAs:InGaAlAs) with a large temperature gradient (ΔT ∼ 200 K) have been measured and are within 3%-7% of the independently measured values.