Alternative vapor–liquid–solid process in Au-assisted growth of silica nanowires

•Silica nanowires were grown using Si wafer coated with a thick Au film as a catalyst.•The nanowires have Au particles inside them, different from those reported.•An alternative vapor–liquid–solid process for the nanowire growth is presented.

We report the growth process of silica nanowires (NWs) grown by using a thick Au film as a catalyst, and suggest an alternative vapor–liquid–solid mechanism for NW growth. The silica NWs were grown by high-temperature annealing of silicon substrates coated with an Au film measuring either 20 nm or 60 nm thick in a N2 atmosphere. A number of Au particles were observed inside the NWs, unlike NWs grown a single Au particle at their top. The results are attributed to the push-up growth of NWs by the continuous formation of silicon oxide on the top and/or side surfaces rather than underneath of the eutectic liquid Au–Si alloy suggested in the conventional vapor–liquid–solid process.