Improvement of thermoelectric properties induced by uniquely ordered lattice field in Bi2Se0.5Te2.5 pillar array

In this study, it was found that uniquely ordered lattice field favors transport of carriers but hinder that of phonons. The Bi2Se0.5Te2.5 pillar array film with a thermoelectric dimensionless figure-of-merit ZT=1.28 was obtained at room temperature. The in-plane transport mechanisms of the ordered pillar array and the ordinary structures, the lattice field model, are proposed and investigated. The specially ordered lattice field is the main reason for the properties enhancement observed in the Bi2Se0.5Te2.5 pillar array. Introduction of such uniquely ordered lattice field into TE films is therefore a very promising approach. In (a) TEM and (b) HRTEM images of the ordered Bi2Se0.5Te2.5 column array.