Size-Dependent Thermal Conductivity of Thick Low-Dimensional Silicon Nanostructures

YF Huang and CF Hou and W Li and G Zhang and W Ge, JOURNAL OF PHYSICAL CHEMISTRY C, 129, 13813-13821 (2025).

DOI: 10.1021/acs.jpcc.5c03543

In this work, using extreme-scale atomistic nonequilibrium molecular dynamics (NEMD) simulation, we simulate silicon nanostructures with a maximum characteristic size of 54.31 nm and a maximum length exceeding 5.2 mu m, which contains up to 0.5 billion silicon atoms. The finite- length effects and characteristic size effects on the thermal conductivity of silicon nanowires and nanofilms are illustrated. The length effects on thermal conductivity are more sensitive in silicon nanofilms than in silicon nanowires, and the transition occurs earlier in silicon nanowires than that in silicon nanofilms. In contrast, silicon nanowires exhibit more significant characteristic size effects than silicon nanofilms. Furthermore, based on the conquered finite- length effects in NEMD simulations and the coupling with the kinetic theory equation, a model is established to effectively predict the thermal conductivity of thick silicon nanostructures with different characteristic sizes and longitudinal lengths. Our model demonstrates good agreement with the characteristic size-dependent and bulk thermal conductivity of silicon measured experimentally.

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