Effect of structural features on the thermal conductivity of SiGe-based materials

HAHN, KONSTANZE REGINA;MELIS, CLAUDIO;COLOMBO, LUCIANO

2014-01-01

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Abstract

Approach-to-equilibrium molecular dynamics have been utilized to investigate the thermal transport in SiGe based materials focusing on the effect of structural changes while the chemical composition has been kept constant. At a Si:Ge ratio of 1:1, the thermal conductivity has been evaluated for crystalline SiGe with a periodic (ZnS-like) and random (alloy) distribution of Si and Ge atoms, for SiGe nanocomposite and for amorphous SiGe. Thermal conductivity has been found to be lowest in amorphous SiGe (0.9 W/mK). In the regime studied here, a non-linear behavior of 1/κ to 1/Lz has been observed for amorphous SiGe, while a linear trend is found for all crystalline materials (ZnS-like, alloy and nanocomposite). This has been attributed to a wide spread in the mean free path of phonons dominating the thermal transport in the amorphous system.