Interfacial thermal conductance between few to tens of layered-MoS2 and c-Si: Effect of MoS2 thickness

We report a systematic investigation of interfacial thermal conductance (Gk) between few to tens -layered mechanical exfoliated molybdenum disulfide (MoS2) and crystalline silicon (c-Si). Based on Raman spectroscopy, we find Gk at room temperature increases with increased layer numbers of MoS2 from 0.974 MW m−2 K−1 to 68.6 MW m−2 K−1. The higher Gk of thicker samples reveals their better interface contact with the substrate, leading to accordingly improved interfacial energy coupling. Molecular dynamics (MD) simulations are conducted to interpret and compare with the experimental observations. MD simulations predict a thermal conductance in the range of 53–77 MW m−2 K−1, which agrees well with the upper bound Gk measured in our work. The thickness dependence of measured Gk reflects the improved interface spacing for thicker MoS2 samples. This phenomenon is further confirmed by the Raman intensity enhancement study by the interface spacing and local optical interference calculations.

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