Effect of morphology on the phonon thermal conductivity in Si/Ge superlattice nanowires

We used nonequilibrium molecular dynamics to investigate the role of morphology in the phonon thermal conductivity of 100, 110, 111 and 112-oriented Si/Ge superlattice nanowires at 300 K. Such nanowires with 112 growth direction were found to possess the lowest values of the thermal conductivity [1.6 W/(m center dot K) for a Si and Ge segment thickness of similar to 3 nm] due to the lowest average group velocity and highly effective {113} facets and Si/Ge(112) interface for phonon-surface and phonon-interface scattering, respectively. Comparison with homogeneous and core/shell Si and Ge nanowires showed that the superlattice morphology is the most efficient to suppress the thermal conductivity.

Automated summary

We used nonequilibrium molecular dynamics to study the effect of morphology on the phonon thermal conductivity of Si/Ge superlattice nanowires with different orientations. The 112-oriented nanowires showed the lowest thermal conductivity due to their unique structure featuring effective phonon-surface and phonon-interface scattering. Comparison with other types of nanowires revealed that the superlattice morphology is the most efficient in reducing thermal conductivity.