Single-impurity scattering and carrier mobility in doped Ge/Si core-shell nanowires.

We report electronic transport properties of doped Ge-core/Si-shell and Si-core/Ge-shell nanowires (NWs) from first-principles. We obtain single-impurity scattering properties of electrons and holes using density-functional methods for quantum conductance and then estimate charge-carrier mobilities considering multiple impurity scatterings. It is found that holes in the Ge-core/Si-shell NW with B-doped Si and electrons in the Si-core/Ge-shell NW with P-doped Ge have higher mobilities than holes and electrons in other chemical and doping configurations. These results reflect asymmetric radial confinements of charge carriers in the core-shell NWs and show that Si-core/Ge-shell NWs with electron donors in the shell are as promising for nanoelectronic devices as Ge-core/Si-shell NWs with electron acceptors in the shell.