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Thermal boundary conductance of CVD-grown MoS$_2$ monolayer-on-silica substrate determined by scanning thermal microscopy

We characterize heat dissipation of supported molybdenum disulfide (MoS$_2$) monolayers grown by chemical vapor deposition by means of ambient-condition scanning thermal microscopy (SThM). We find that the thermal boundary conductance of the MoS$_2$ monolayers in contact with 300 nm of SiO$_2$ is around 4.6 $\pm$ 2 MW m$^{-2}$ K$^{-1}$. This value is in the low range of the values determined for exfoliated flakes with other techniques such as Raman thermometry, which span an order of magnitude (0.44-50 MW m$^{-2}$ K$^{-1}$), and underlines the dispersion of measurements. The sensitivity to the in-plane thermal conductivity of supported MoS$_2$ is very low, highlighting that the thermal boundary conductance is the key driver of heat dissipation for the MoS$_2$ monolayer when it is not suspended. In addition, this work also demonstrates that SThM calibration using different thicknesses of SiO$_2$, initially aimed at being used with bulk materials can be extended to 2D materials.