摘要
A facile compositional tuning by Sb and Cu addition is performed to generate engineered defects in GeTe alloys with ultra-low thermal conductivity.Substitution of Sb and Cu at the Ge-site enhances the power factor due to the optimization of carrier concentration while maintaining the convergence of the valence bands.Furthermore,complex multi-dimensional defect structures including 0D(0-dimensional)substituted Sb_(Ge)and Cu_(Ge),2D twin and inversion boundaries,3D herringbone structures,3D embedded nanostructures,and 3D Cu-rich coherent precipitates are generated,which significantly reduce the lattice thermal conductivity benefitting from a collective phonon scattering.Due to this simultaneous manipulation of electronic and thermal transport properties,a maximum thermoelectric figure of merit(zT)of 1.4 was obtained at 723 K.
基金
supported by grants from the National Research Foundation(NRF)of Korea(No.2021R1A4A2001658)
funded by the Korean government(MSIT).
