Controlling Thermal Diffusion by Nanoscale Structural Arrangement in SiGe Superlattices

ABSTRACT

Superlattices are considered one of the most promising material systems for nanotechnological applications owing to the possibility that these materials could be tailored to obtain desired thermal properties. In this study, non-equilibrium molecular dynamics (NEMD) simulations are performed to obtain an understanding of the effect of monolayer film thickness, periodicity, heat flow direction, straining, and temperature of operation on the thermal conductivity of Si-Ge superlattices at three different temperatures (400K, 600K, and 800K). The thermal conductivity is found to increase with an increase in the number of periods as well as with increase in the period thickness. The dependence of thermal conductivity on the direction of heat flow is found to be sensitive to the extent of acoustic mismatch at the interface. Both compressive and tensile strains are observed to be an important factor in tailoring the thermal conductivity of the analyzed superlattices.

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