Theoretical study on thermal properties of molybdenum disulfide/silicon heterostructures

JF Wang and S Wu and HQ Xie and LT Xiong, COMPUTATIONAL MATERIALS SCIENCE, 200, 110835 (2021).

DOI: 10.1016/j.commatsci.2021.110835

Because of the wide application of molybdenum disulfide in electronics and catalysis fields, the thermal management of MoS2/Si heterogeneous devices is very important. The structures of the molybdenum disulfide/silicon (MoS2/Si) heterostructure were optimized by the First- principles density functional theory. The interfacial thermal conductance of 16 layers MoS2/Si was investigated by the molecular dynamics. The phonon density of states (DOS) curve for a single atom in MoS2/Si has a weak peak height compared with Si and MoS2 layers because the interface structure interferes with the vibration of the single atom. Compared with the isolated MoS2 layers, the phonon DOS peak of the atom Mo in MoS2/Si is almost remaining unchanged while the atom S peak is slightly shifted. The peak position and peak height of curves of the single Si atom in MoS2 /Si and Si bulk are different in the same direction. The thermodynamic properties of MoS2 /Si are calculated based on the phonon properties. We analyzed how the heat capacity (C-nu), the total energy (E-T), Helmholtz free energy (A(T)), and entropy (S-T) of MoS2 /Si change with temperature and compared them with those of Si bulk and MoS2 layers. The results show that each thermodynamic faction curve of MoS2 /Si has a similar trend with temperature as that of Si and MoS2 layers. The obtained thermal conductance (G) between 16 layers MoS2 and Si bulk is 17.05 MWm(-2) K-1 at 300 K based on the molecular dynamics. The G of interface increases with interactions between Si and MoS2 layers, and temperature. This study will play an important role in the application of MoS2 in thermal management of electronic devices.

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