Abstract
The discovery of band convergence has opened an effective avenue for significantly enhancing thermo-electric performance of SnTe,while alloying CdTe in SnTe is evidenced efficient for improving the valley degeneracy.However,the thermoelectric transport properties are limited due to the low solubility of CdTe in SnTe (～3％).Inspired by the improvement of dimensionless figure of merit zT in Cu or Se-doped SnTe,investigating the effect of Cu2Se on the electronic and phonon transport properties of SnTe-CdTe alloys is highly desired.Traditionally,improving the quality factor can trigger an increase of the potential of a compound for higher zT,which is of importance for design of thermoelectric materials.Here,alloyed 3％ Cu2Se in SnTe-3％CdTe system enables an increased peak zT,which is attributed by the optimization of electronic performance (～21 μW cm-1 K-2 at 800 K),as well as the decreased lattice thermal conductivity owing to the enhanced mass and strain fluctuations.More importantly,alloying Cu2Se not only improves the quality factor from ～0.25 to ～0.45,resulting in a higher maximum potential zT,but also effectively preserves the Fermi energy in a relative optimized level.The current findings demonstrate the role of Cu2Se for manipulating thermoelectrics in SnTe.
基金项目
National Key Research and Development Program of China(2018YFA0702100)
Joint Funds of the National Natural Science Foundation (NNSF) of China()
Chinese Academy of Sciences' Large-Scale Scientific Facility(U1932106)
NNSF of China(51771126)
Nuclear Power Technol-ogy Innovation Center(NPTIC) of China(HG2020065)
Sichuan University Innovation Research Program of China(2020SCUNL112)
World First-Class University Con-struction Funding of China()
NETL
NSTL
万方数据