Optimizing the thermoelectric transport properties of Bi2O2Se monolayer via biaxial strain

Abstract

Recent studies have shown that the two-dimensional semiconductor Bi₂O₂Se is a promising thermoelectric (TE) material, whereas its TE performance needs to be further improved. By using first-principles methods combined with semi-classical Boltzmann transport theory, we systemically investigate the effects of biaxial strain on the TE transport properties of Bi₂O₂Se monolayer. Under −2–2% strain, the maximum power factors of 3.63–3.79 and 1.43–1.79 mW m⁻¹ K⁻² are found for p-type and n-type doped Bi₂O₂Se monolayer, respectively. The figure of merit ZT of p-type doped Bi₂O₂Se monolayer is enhanced to 1.14 by 2% tensile strain at 300 K and it reaches as high as 4.22 at 800 K (as compared with the highest value of 1.42 for bulk Bi₂O₂Se at 800 K). This study demonstrates that the TE performance of Bi₂O₂Se can be significantly improved by application of tensile strain and the Bi₂O₂Se monolayer has great potential as a TE material.