Plasmonic nanosponges are a powerful platform for various nanophotonic applications owing to extremely high local field enhancement in metallic nanopores. The filling of the nanopores with high-refractive index semiconductors (e.g. Si, Ge, GaP, etc.) opens up opportunities for the enhancement of nonlinear effects in these materials. However, this task remains challenging due to the lack of knowledge on the integration process of metal and high-index semiconductor components in such nanoobjects. Here, we investigate metal-dielectric nanoparticles fabricated from bilayer Si/Au films by the laser printing technique via a combination of theoretical and experimental methods. We reveal that these hybrid nanoparticles represent the Au sponge-like nanostructure filled with Si nanocrystallites. We also demonstrate that the Au net provides strong near-field enhancement in the Si grains increasing the white light photoluminescence in the hybrid nanostructures compared to uniform Si nanoparticles. These results pave the way for engineering the internal structure of the sponge-like hybrid nanoparticles possessing white light luminescence and control of their optical properties on demand.

High-throughput laser printing of resonant silicon nanoparticles has emerged as a novel tool for the fabrication of deeply subwavelength objects with various functionalities. The applications of resonant silicon nanoparticles crucially depend on their crystalline state. However, the ways to control the crystalline structure during laser printing remain unstudied. Here we demonstrate, both experimentally and theoretically, how the crystalline structure of silicon nanoparticles fabricated by a laser printing technique can be varied from almost amorphous to a polycrystalline state. In particular, we propose a method of crystalline structure control via changing the distance between the irradiated silicon film and the receiving substrate. This study allows the most optimal conditions for second harmonic generation to be revealed. We believe that the proposed method opens the door to fully controllable laser printing of functional nanoparticles and nanostructures.

The glass transition of an overcooled aluminum melt upon isobaric and isochoric cooling is studied by means of molecular dynamics. The embedded-atom potential is used to model the aluminum. Three criteria of glass transition (splitting of the second peak of the pair correlation function, an increase in the number of icosahedral clusters, and a change in the activation energy of self-diffusion) are considered. It is shown that the glass transition temperatures determined by these three criteria coincide within the error range. The dependence of the glass transition temperature on the cooling rate is determined from the modeling results and agrees with the Bartenev theoretical model.