Strain and Doping in Two-Dimensional SnTe Nanosheets: Implications for Thermoelectric Conversion

Among thermoelectric materials, tin telluride has been attracting significant interest for its nontoxic and eco-friendly nature. Meanwhile, band engineering and ultrathin film technologies have been reported to be promising in improving the performance of thermoelectric materials. In this work, we explore the potential of two-dimensional (2D) SnTe’s thermoelectric performance, following the recent successful synthesis of 2D SnTe. It is found that pristine 2D SnTe is more likely to be a p-type semiconductor due to the existence of Sn vacancies. The electrical transport properties of 2D SnTe when it is (i) under compressive stress and (ii) doped with either nitrogen group or halogen group elements (including As, Sb, Bi, Br, and I) have been studied from first-principles electronic structure calculations. Boltzmann transport study illustrates that equibiaxial compressive stress may enhance the electrical transport properties of 2D SnTe. Moreover, our calculations suggest that iodine and arsenic can be effective n-type and p-type dopants, respectively.