First-principles investigations of structural, electronic and thermoelectric properties of Sb/Bi2Se3 van der Waals heterostructure

Abstract

Herein, we report first-principles calculations combined with the semi-classical Boltzmann theory in order to highlight the great thermoelectric potential of Sb/Bi2Se3 van der Waals (vdW) heterostructure. The electronic structure and thermoelectric properties of Sb and Bi2Se3 monolayers, and Sb/Bi2Se3 heterostructure have been investigated. The predicted results exhibited all studied materials present a semiconducting behavior, with band gaps found to be Eg=1.29, 0.85, and 0.25eV for Sb and Bi2Se3 monolayers and Sb/Bi2Se3 vdW heterostructure, respectively. The effect of the temperature and chemical potential on transport properties has been demonstrated. It is worth mentioning that the electronic figure of merit (ZTe) exhibits two peaks at room temperature, with an uttermost value of 11.22 at −0.054 Ry and 11.19 at 0.044 Ry, suggesting that a remarkable value of ZTe can be attained through n-type/p-type doping for Sb/Bi2Se3 vdW heterostructure. Moreover, ZTe increases sharply above 400 K and reaches a value of 18.34 at 500 K for Sb/Bi2Se3 vdW heterostructure. This finding could indicate a good future thermoelectric potential to integrate this of this Sb/Bi2Se3 heterostructure into the application of clean electric energy production.