Modeling of formation mechanism and optical properties of Si/Au core-shell nanoparticles

Fabrication of metal/semiconductor (“hybrid”) nanoparticles is still a challenge due to the absence of methods of a metal core coating by crystalline semiconductor shell. We propose a novel principle of formation of a core-shell nanoparticle made of liquid silicon and gold droplets. Molecular dynamics simulations of the droplets behavior demonstrates that the core-shell structure with a gold core and a silicon shell can be formed if the droplets remain in the liquid state until final material redistribution. The main driven force in this process is surface tension governed by surface energies of the droplets, where silicon tends to cover gold due to lower surface energy. Taking into account this mechanism of core-shell nanoparticles formation, we provide numerical modelling, which demonstrates the resulting nanoparticle posses enhanced local electromagnetic field, high Purcell factor and flexible power patterns of scattered light.