Enhanced thermal transport across monolayer MoS2

Characterizing the thermal properties of MoS2 is important for the design of electronic devices based on this material. We used frequency domain thermoreflectance to study the cross-plane thermal transport in mechanically exfoliated MoS2 samples supported on SiO2 and muscovite mica substrates. The thickness of MoS2 ranged between one and five layers, and the MoS2 layers were sandwiched between a metal layer and the substrate. In the case of mica, heat transport into the substrate remained the same whether or not a monolayer of MoS2 was present, whereas, for SiO2, heat transport was reduced by surface roughness. We observed a significant improvement in heat transport across monolayer MoS2 as compared to few layer MoS2. For MoS2 on SiO2, the effective thermal interface conductance was improved by more than three times if a monolayer was used. For MoS2 on mica, the thermal interface conductance was approximately two times better for monolayer MoS2. This implies that monolayer MoS2 has superior thermal properties and can be used in electronic devices as an intermediate layer between two materials. Additionally, we also report on the measurement of anisotropic thermal conductivity in bulk MoS2 and mica.