Formation of Hybrid Silicon Nanostructures via Capillary Instability Triggered in Inductively‐Coupled‐Plasma Torch Synthesized Ultra‐Thin Silicon Nanowires

Abstract

This paper provides a report on the formation of two main classes of hybrid silicon nanostructures via the capillary instability induced in ultra‐thin silicon nanowires (SiNWs) when subject to high temperature annealing. The first class of hybrid Si nanostructures shows a high‐level nanostructural order, and regroups (i) periodic strings of almond‐shaped Si nanocrystals (SiNCs) having average dimension of 3 nm and connected by ultra‐thin (≈2 nm) SiNWs and (ii) spherical SiNC chains (mean diameter of 6 nm, spaced by 16 nm on average), both embedded into silica NWs. In the second class of hybrid Si nanostructures, the SiNCs have different dimensions (in the 3–14 nm size range) and shapes, or a modulated Si core inside a SiO2 shell, thus exhibiting much higher nanostructural complexity. The self‐assembly of such nanostructures is related to the gas ambient under which the thermal treatment is performed. However, by increasing the annealing temperature, the SiNWs’ cores preferentially evolve toward the spherical SiNC chain morphology. The ultra‐thin diameter (2–3 nm) of the initial SiNWs is a key feature to induce the hybrid Si nanostructures formation. This study opens up the prospects of in situ controlling the formation of Si nanocrystals inside silica NWs, which will lead to the tailoring of their optoelectronic properties.

Ultrafast Carrier Relaxation Dynamics in Quantum Confined Non-Isotropic Silicon Nanostructures Synthesized by an Inductively Coupled Plasma Process

“…The morphologies of both as-grown and centrifuged silicon nanopowder have been investigated in details by scanning electron microscopy (SEM) and TEM, as reported elsewhere [ 15 , 29 ]. The AG silicon nanopowder consists of entangled few-µm-long NW and nanospheres (NSP) with various sizes (from few to 100 nm-diam.).…”