Formation of Single-Crystal Spherical Particle Architectures by Plasma-Induced Low-Temperature Coalescence of Silicon Nanocrystals Synthesized by Laser Ablation in Water

Abstract

We report that the synthesis of silicon nanocrystals (SiNCs) by laser ablation in water produces unique surface characteristics and, in particular, hydroxyl-terminated surfaces, which can induce coalescence and formation of micrometer-sized single-crystal Si spherical particles under a low-temperature (∼550 °C) plasma process. We demonstrate that the spherical particles can be self-organized into aggregates that extend with varying gas concentrations. At the same time, SiNCs that were sufficiently apart not to coalesce have shown peculiar photoluminescence properties, which suggest an increased tunneling probability from self-trapped excitonic surface states.