Heat conduction characteristic of 3D nano-silicon thin films induced by ultrafast laser

In this study, the lattice Boltzmann method was utilized to explore the heat conduction characteristic of 3D nano-silicon thin films subjected to ultrafast laser irradiation. The impacts of boundary conditions and size effects of the film on heat conduction are analyzed. We found that under the high power of the ultrafast laser exposure, the thin film's heat conduction exhibits marked directionality, leading to substantial temperature gradients along the film's radial direction. To mitigate the pronounced temperature gradients, we introduces a novel dual laser heat source strategy, designed to equilibrate internal thermal stresses within the film. Crucially, the manipulation of the dual laser's energy distribution enables control over the film's internal temperature field, offering groundbreaking insights for the thermal management and design of nanoscale films. Furthermore, by compared the D3Q19 model with D2Q9 and D1Q3 counterparts, we found that the transition from 1D to 2D resulted in a 27.03% reduction in the peak value of the thermal wave, while the transition from 2D to 3D further reduced the peak value by 14.46%. From the point of view of wave characteristics, the 3D model can more accurately simulate the complexity of actual heat wave propagation. •Here are the highlights:•D3Q19 lattice Boltzmann method for nano-silicon film heat conduction.•Impact of film size and boundary conditions on heat-transfer properties.•Boundary conditions is crucial for phonon transport in ballistic state.•Dual laser heat sources enable precise temperature control in films.