  State-of-the-art fabrication and characterization techniques have been
employed to measure the thermal conductivity of suspended, single-crystalline
MoS2 and MoS2/hBN heterostructures. Two-laser Raman scattering thermometry was
used combined with real time measurements of the absorbed laser power, which
allowed us to determine the thermal conductivities without any assumptions.
Measurements on MoS2 layers with thicknesses of 5 and 14 exhibit thermal
conductivity in the range between 12 and 24 Wm-1K-1. Additionally, after
determining the thermal conductivity of a selected MoS2 sample, an hBN flake
was transferred onto it and the effective thermal conductivity of the
heterostructure was subsequently measured. Remarkably, despite that the
thickness of the hBN layer was less than a third of the thickness of the MoS2
layer, the heterostructure showed an almost eight-fold increase in the thermal
conductivity, being able to dissipate more than 10 times the laser power
without any visible sign of damage. These results are consistent with a high
thermal interface conductance between MoS2 and hBN and an efficient in-plane
heat spreading driven by hBN. Indeed, we estimate G 70 MWm-2K-1 which is
significantly higher than previously reported values. Our work therefore
demonstrates that the insertion of hBN layers in potential MoS2 based devices
holds the promise for efficient thermal management.
