EXAFS study of thermoelectric BiCuOSe: Effects of Cu vacancies

Abstract

Excellent thermoelectric performance has been reported for the ZrCuSiAs-type BiCuOSe derivatives; for these materials the transport properties can be effectively adjusted by chemical substitutions or by introducing Cu vacancies. In this work we compare stoichiometric BiCuSeO and its Cu-deficient derivative BiCu0.95SeO by utilizing temperature dependent extended X-ray absorption fine structure (EXAFS) measurements. Such a local probe evidences that Cu vacancies make the lattice more ductile and susceptible to temperature variation. (C) 2015 Elsevier Ltd. All rights reserved.