Enhancement of the Seebeck Coefficient of C doped SnSe: First Principles Study

Abstract

The effect of C dopant on the electronic structure and thermoelectric properties of SnSe has been studied using density functional theory (DFT) and by solving the Boltzmann transport equation (BTE). We found that the substitution of C into the Sn site creates a strongly localized defect state with a sharp density for the state peak. This strong modification of band structure reduces the band gap from 0.61 eV to 0.42 eV. It was found that the maximal Seebeck coefficient can be enhanced up to 17.1% and the maximal temperature reduces from 525 K to 280 K. These behaviors can be understood using the Mott equation and Goldsmid – Sharp relation.