Thermal Conductance at the 2D MoS$_{\mathrm{2}}$-hexagonal Boron Nitride Interface

In recent years, a number of 2D heterostructure devices have emerged, including graphene/hexagonal boron nitride ($h$-BN), graphene/MoS$_{\mathrm{2}}$ and MoS$_{\mathrm{2}}$/$h$-BN. Among them, MoS$_{\mathrm{2}}$/$h$-BN field-effect transistors with MoS$_{\mathrm{2}}$~channels and~$h$-BN dielectric have been reported to have higher carrier mobility and reduced hysteresis compared to MoS$_{\mathrm{2}}$~on SiO$_{\mathrm{2}}$. Despite relatively high in-plane thermal conductivity of MoS$_{\mathrm{2}}$~and~$h$-BN, heat dissipation from these 2D devices is mainly limited by heat transfer in the vertical direction. Consequently, their operating temperatures are strongly influenced by the interface thermal conductance. In this work, we demonstrate the measurement of interface thermal conductance between MoS$_{\mathrm{2}}$~and~$h$-BN. This is realized by electrically heating MoS$_{\mathrm{2}}$~and monitoring their temperatures through Raman spectroscopy. The obtained interface thermal conductance between MoS$_{\mathrm{2}}$~and~$h$-BN is 1.77 MW/m$^{\mathrm{2}}$K, smaller than the reported value for the graphene/$h$-BN interface, due to the weak coupling of phonon modes between MoS$_{\mathrm{2}}$~and~$h$-BN based on our NEGF calculation. The low interface thermal conductance value suggests this interface is not favorable for heat dissipation, and should be considered carefully for the design of electronic and optoelectronic devices based on MoS$_{\mathrm{2}}$/$h$-BN heterostructures.