Controllable synthesis of silicon nano-particles using a one-step PECVD-ionic liquid strategy

Abstract

Silicon nano-particles (SiNPs) offer the promise of an environmentally friendly and manufacturable material because of their inherent non-toxicity and compatibility with Si-based technologies. However, their controllable synthesis on a large scale remains a challenge. Herein, we present a facile method that takes advantage of both plasma enhanced chemical vapour deposition (PECVD) and ionic liquid (IL), referred to as PECVD-IL methods to controllably synthesize well-dispersed SiNPs. It has been found that Si-based radicals within silane plasma can be passivated by IL “soft substrates”, and then SiNPs with sizes ranging from 2.3 to 4.5 nm with a narrow size distribution (±0.8 nm) can be readily synthesized. Moreover, the size of the SiNPs can be well controlled by adjusting the residence time of Si radicals in the plasma. This work demonstrates the feasibility of vapour phase deposition on liquid-based substrates, which provides the ability to allow for “species selection” to controllably synthesize well-dispersed SiNPs with small size-distribution.