Inspired by metal corrosion in air, we demonstrate that metal-catalyzed electroless etching (MCEE) of silicon can be performed simply in aerated HF/H2O vapor for facile fabrication of three-dimensional silicon nanostructures such as silicon nanowires (SiNW) arrays. Compared to MCEE commonly performed in aqueous HF solution, the present pseudo gas phase etching offers exceptional simplicity, flexibility, environmental friendliness, and scalability for the fabrication of three-dimensional silicon nanostructures with considerable depths, because of replacement of harsh oxidants such as H2O2 and AgNO3 by environmental-green and ubiquitous oxygen in air, minimum water consumption and full utilization of HF.
Nano Letters, 2014
Photographs and SEM images of AgNPs-coated Si substrates after 5h duration (a) In HF-free atmosphere, (b) Submerged in 20% aqueous HF solution, and (c) In atmospheric HF/H2O vapor.
A schematic diagram of experimental set-up used for MCEE of silicon in aerated HF/H2O vapor. Inset shows the photograph of wafer-scale SiNW array on a 4-inch silicon wafer.
