Microstructure evolution of Si nanoparticles during the melting process: Insights from molecular dynamics simulation

Si nanomanufacturing has attracted considerable attention in the manufacturing of advanced thermoelectric materials and microelectronics owing to its compatibility with the semiconductor industry. The microstructure determines physical and chemical characteristics of a material; however, it is difficult to observe the microstructural evolution using traditional experimental methods. In this study, the melting process of Si nanoparticles is studied in depth by classical molecular dynamics (MD) simulation. Using the entropy of the largest standard cluster and the pair distribution function, the microstructural evolution characteristics can be determined. The transformation of Si-like structures was examined by largest standard cluster analysis (LaSCA). The results show that the melting process begins at the surface and rapidly penetrates into the nanoparticles at a high heating rate, indicating a liquid nucleation and growth (LNG) mode. At a higher heating rate, the temperature range of the solid and liquid coexistence will be larger. This study provides an understanding of the melting behavior of Si nanoparticles at the atomic scale and a useful reference for the preparation and processing of nanodevices.