Substitutional and interstitial impurity p-type doping of thermoelectric Mg2Si: a theoretical study.

ABSTRACT: The narrow-gap magnesium silicide semiconductor Mg2Si is a promising mid-temperature (600-900 K) thermoelectric material. It intrinsically possesses n-type conductivity, and n-type dopants are generally used for improving its thermoelectric performance; however, the synthesis of p-type Mg2Si is relatively difficult. In this work, the hole doping of Mg2Si with various impurity atoms is investigated by performing first principles calculations. It is found that the Ag-doped systems exhibit comparable formation energies ΔE calculated for different impurity sites (Mg, Si, and interstitial 4b ones), which may explain the experimental instability of their p-type conductivity. A similar phenomenon is observed for the systems incorporating alkali metals (Li, Na, and K) since their ΔE values determi

SUBMITTER: Hirayama N 

PROVIDER: S-EPMC6419642 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature