The use of the grey-Taguchi method for the optimization of a silicon nanowires array synthesized using electroless Ag-assisted etching

A simple and convenient method for the production of silicon nanowires (SiNWs) that are single crystalline, well aligned and which have large area is direct synthesis onto p-type (100) silicon (Si) wafers, using electroless Ag-assisted etching, in which Ag is both the oxidant and the catalyst. This study proposes a method for the optimization of the etching process parameters for SiNW arrays with multiple performance characteristics, using grey-Taguchi analysis. The effect of the etching process parameters (etching time, solution (AgNO₃/HF) temperature, silver nitrate (AgNO₃) concentration and hydrogen fluoride (HF) concentration) on the length, diameter, structure, and morphology of the SiNW arrays were studied. In the confirmation runs, grey relational analysis shows that the length of the SiNW arrays is increased from 15.80 to 23.07 μm, and the diameter is decreased from 76.77 to 66.65 nm. Further, the linear relationship for the SiNW arrays can be adjusted by increasing the etching time (from 15 to 45 min) and the solution temperature (from 25 to 75 °C). The axial orientation of the SiNWs is determined to be along the [001] direction, which is the same as that of the initial Si wafer. The large area SiNW arrays have potential applications in interconnect, bio-technology and optoelectronic devices.