Influence of Compensating Defect Formation on the Doping Efficiency and Thermoelectric Properties of Cu2ySe1xBrx
Abstract
The super ionic conductor Cu2Se has been shown to be a promising thermoelectric at higher temperatures because of very low lattice thermal conductivities, attributed to the liquid-like mobility of copper ions in the super ionic phase. In this work, we present the potential of copper selenide to achieve a high figure of merit at room temperature, if the intrinsically high hole carrier concentration can be reduced. Using bromine as a dopant, we show that reducing the charge carrier concentration in Cu2Se is in fact possible. Furthermore, we provide profound insight into the complex defect chemistry of bromine doped Cu2Se via various analytical methods and investigate the consequential influences on the thermoelectric transport properties. Here, we show, for the first time, the effect of copper vacancy formation as compensating defects when moving the Fermi level closer to the valence band edge. These compensating defects provide an explanation for the often seen doping inefficiencies in thermoelectrics via defect chemistry and guide further progress in the development of new thermoelectric materials.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 24, 2015
- Accession Number
- AD1015570
Entities
People
- Bor-rong Chen
- G. Jeffrey Snyder
- Kai S. Weldert
- Klaus P. Jochum
- Martin Panthöfer
- Michael Bedzyk
- Stephanie L. Moffitt
- Tristan W. Day
- Ulrike Weis
- Wolfgang G Zeier
- Wolfgang Tremel
Organizations
- California Institute of Technology