Orientation and size effects on phonon thermal conductivity in silicon/germanium multilayer structures

Abstract

We study the effect of morphology on the in- and cross-plane phonon thermal conductivity of the (001), (110), and (111) oriented Si/Ge multilayer films by means of non-equilibrium molecular dynamics at 300 K. The extended comparison of the estimated values for the multilayer films to one for the appropriate homogeneous Si and Ge films has been performed. The results revealed a significant advantage in reducing the thermal conductivity of the Si/Ge multilayer films compared to the referenced homogeneous Ge and Si films for the cross-plane transport regardless of the film orientation, and for the in-plane transport only for (001)/[1¯10], (110)/[001] directions with an increase in the number of periods, which indicated the prospects of such layered structures.