Core–shell Si1−xGex nanowires with controlled structural defects for phonon scattering enhancement

We demonstrate for the first time core-shell Si1-xGex alloy nanowires that can suppress the phonon propagation in nanowires without reducing the electrical conductivity. Non-uniformly distributed structural defects in the outer shells of the Si1-xGex nanowires enhance boundary scattering during phonon transport, while a defect-free core provides a current path for electrical carriers.