Optimizing of porous silicon alloying process with bimetallic nanoparticles

Bimetallic Ag–Au alloy nanoparticles with a tunable size and composition were synthesized by laser beam power density. A set of Psi substrates with different morphologies fabricated by laser-assisted etching process with laser power density from 10 to 40?mW/cm² was explored as a substrate for materialization bimetallic Ag–Au alloy nanoparticles by a simple immersion plating process of Psi in a mixture of AgNO3 and HAuCl4 solutions. The materialization of alloy nanoparticles was confirmed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray analysis (EDS). The results showed that the sizes and distribution of Ag–Au alloy nanoparticle sizes were easily well-ordered by changing the surface morphologies of Psi layer. Pore-like structures with different pores shapes: ultra-fine pores, irregular (grotto form), circular, and star full pore shape (gambling pores) with different sizes were prepared by changing the irradiation laser power density. Bimetallic Ag–Au alloy nanoparticles, phases, crystalline size, specific surface area, and growth sites of Ag–Au alloy nanoparticles were significantly influenced by pore shape. The lower nanoparticle size with higher S.S.A was obtained when the laser power intensity was about 30?mW/cm².