Growth of bulk functionalized silicon nanowires: importance of the gaseous phase
Résumé
Silicon nanowires (SiNWs) have remarkable properties allowing new applications. For
example, Li-ion batteries performances can be significantly improved[1]. It is therefore interesting to
produce them in an easy and quantitative way, and our team recently patented a new innovative growth
process in this way. It allows high yield and bulk production of SiNWs, thanks to a non-dangerous
organosilane precursor, a gold nanoparticle catalyst, and a sacrificial support in NaCl[2]
. The assynthetized SiNWs are surface functionalized, which is very useful for making SiNWs/carbon
composites. With this new process, the SiNWs diameter is always close to 10 nm with a sharp
distribution; the reason is not clear. In the present work we focus on the reaction mechanism, with the
aim to understand the size limitation and the way the functionalization is happening. Electronic
microscopy on SiNWs after a short reaction time revealed that 2 distinct populations of SiNWs with
different diameters (6nm and 10nm) are formed separately at different reaction times. Also, by using
NMR spectroscopy and a scavenger, we show that silylenes are part of the process as reaction
intermediates. The gaseous phase plays for sure a key role in the mechanism, and the understanding
of the steps occurring there is fundamental for the tunability of the SiNWs.
1. Chan C.K., Peng H., Liu G. McIlwrath K., Zhang X.F., Huggins R.A. and Cui Y., Nature Nano., 2008, 3, 31-34
2. Chenevier P., Reiss P., Burchak O., Method for Producing Silicon Nanowires, FR3022234 (A1), 2015