title: Influence of a nano phase segregation on the thermoelectric properties of the p-type doped stannite compound Cu(2+x)Zn(1-x)GeSe4.
abstract: Engineering nanostructure in bulk thermoelectric materials has recently been established as an effective approach to scatter phonons, reducing the phonon mean free path, without simultaneously decreasing the electron mean free path for an improvement of the performance of thermoelectric materials. Herein the synthesis, phase stability, and thermoelectric properties of the solid solutions Cu(2+x)Zn(1-x)GeSe(4) (x = 0-0.1) are reported. The substitution of Zn(2+) with Cu(+) introduces holes as charge carriers in the system and results in an enhancement of the thermoelectric efficiency. Nano-sized impurities formed via phase segregation at higher dopant contents have been identified and are located at the grain boundaries of the material. The impurities lead to enhanced phonon scattering, a significant reduction in lattice thermal conductivity, and therefore an increase in the thermoelectric figure of merit in these materials. This study also reveals the existence of an insulator-to-metal transition at 450 K.
authors.affiliation: Institut für Anorganische Chemie und Analytische Chemie der Johannes Gutenberg-Universität, Duesbergweg 10-14, D-55099 Mainz, Germany.
authors.forename: Wolfgang G
authors.initials: WG
authors.lastname: Zeier
authors.forename: Aaron
authors.initials: A
authors.lastname: LaLonde
authors.forename: Zachary M
authors.initials: ZM
authors.lastname: Gibbs
authors.forename: Christophe P
authors.initials: CP
authors.lastname: Heinrich
authors.forename: Martin
authors.initials: M
authors.lastname: Panthöfer
authors.forename: G Jeffrey
authors.initials: GJ
authors.lastname: Snyder
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Tremel