am7b06872_si_001.pdf (1005.03 kB)
Silicon As an Unexpected n‑Type Dopant in BiCuSeO Thermoelectrics
journal contribution
posted on 2017-08-03, 00:00 authored by Jiahong Shen, Yue ChenAs
a promising thermoelectric material, BiCuSeO is of great interest
for energy conversion. A higher figure of merit in n-type BiCuSeO
than that in the p-type was predicted from theory, suggesting a need
of in-depth investigations on the doping effects. In this work, the
influences of group IV elements (Si, Ge, Sn, and Pb) on the electronic
structures of BiCuSeO are studied from first principles. Despite the
similar electronegativities of the group IV elements, Si is found
to be an n-type dopant, being distinctly different from Ge, Sn, and
Pb, which exhibit typical p-type behaviors. Detailed analysis on the
doping effects is performed based on a recently developed band unfolding
technique. Furthermore, Si-doped BiCuSeO is shown to have a higher
power factor than p-type BiCuSeO from the Boltzmann transport theory.