Thermoelectric Transport in a ZrN/ScN Superlattice

Mona Zebarjadi, University of California - Santa Cruz
Zhixi Bian, University of California - Santa Cruz
Rajeev Singh, University of California - Santa Cruz
Ali Shakouri, University of California - Santa Cruz
Robert Wortman, Purdue University - Main Campus
Vijay Rawat, Purdue University - Main Campus
Timothy D. Sands, Purdue University

Date of this Version

7-2009

Citation

DOI: 10.1007/s11664-008-0639-5

This document has been peer-reviewed.

 

Abstract

Metal/semiconductor superlattices have the potential for a high thermoelectric figure of merit. The thermopower of these structures can be enhanced by controlling the barrier height using high-energy electron filtering. In addition, phonon scattering at interfaces can reduce the lattice contribution to the thermal conductivity. In this paper, we present theoretical and experimental studies of the thermoelectric transport in ZrN/ScN metal/semiconductor superlattices. Preliminary measurement results show an exponential increase in the cross-plane electrical conductivity with increasing temperature, which indicates the presence of the barrier. Fit of the Boltzmann transport-based model with the data indicates a barrier height of 280 meV. The cross-plane Seebeck coefficient of the sample is also measured by combining Seebeck voltage transient measurements with the thermal imaging technique. A Seebeck coefficient of 820 mu V/K at room temperature is extracted, which is in good agreement with the simulation result of 800 mu V/K. Theoretical calculations predict that the ZrN/ScN structure can exhibit a ZT of 1.5 at 1300 K assuming lateral momentum is conserved and that a ZT of 3 is achievable if the lateral momentum is not conserved.

Discipline(s)

Engineering | Nanoscience and Nanotechnology

 

Share