Thermoelectric Properties of Sn-Containing Mg 2 Si Nanostructures
Abstract
The thermoelectric performance of Mg2Si-
containing nanomaterials are predicted based on density-
functional and Boltzmann’s transport theories. The investigated
materials are Mg2Si1−xSnx thin films with x = 0.125 and x =
0.625, and (Mg2Si)1−x (Mg2Sn)x (x = 0.4 and x = 0.6) in the
form of either superlattices or assembled nanosticks. The
calculated properties (Seebeck coefficient S, electrical con-
ductivity σ, and power factor S2σ) are compared with those of
bulk Mg2Si1−xSnx. It is shown that the thin films outperform the
bulk materials at low temperature (350 K) as they exhibit a
higher Seebeck coefficient and comparable electrical conductiv-
ity. A low electrical conductivity at 900 K is responsible for the
counter-performance of the films. Superlattices are attractive
structures as p-doped materials at both low charge carrier
concentration/high temperature and high charge carrier concentration/high temperature. The assembled nanosticks are interesting materials at low carrier concentration/low temperature only.