Phonon Thermal Properties of Transition-Metal Dichalcogenides MoS2 and MoSe2 Heterostructure

Two prototype transition-metal dichalcogenide (TMDC) materials, MoS2 and MoSe2, have attracted growing attention as promising 2D semiconductors. The heterostructure created by stacking the 2D monolayers in the out-of-plane direction exhibits peculiar properties that can be utilized in electronic applications. The lateral and flexural phonon transport behaviors in MoS2/MoSe2 heterobilayer are comprehensively investigated using classical molecular dynamics simulations. In-plane thermal conductivity (kappa) and out-of-plane interfacial thermal resistance (R) are calculated by nonequilibrium molecular dynamics (NEMD) and transient pump probe methods, respectively. Thermal conductivity of MoS2/MoSe2 bilayer 2D sheet is characterized as 28.8 W/m.K, which preserves the high thermal conductivity of most TMDC materials. The maximum K reductions of MoS2, MoSe2, and heterobilayer amount to 83.0, 68.9, and 77.1%, respectively, with increasing temperatures from 100 to 500 K. It is also found that the basal-plane thermal performance of MoS2/MoSe2 bilayer will not be affected by interfacial interactions, which is important in industrial applications. The predicted out-of-plane flexural phonon conductance results reveal that heat flux runs preferably from MoS2 to MoSe2 than in the reverse direction.