Nanowires fine tunable fabrication by varying the concentration ratios, the etchant and the plating spices in metal-assisted chemical etching of silicon wafer.

The metal-assisted chemical etching (MACE) was used to synthesis silicon nanowires. The effect of etchant concentration, etching and chemical plating time and doping density on silicon nanowires length were investigated. It is held that the increasing of HF and H2O2 concentrations lead to etching rate increment and formation of wire-like structure. The results show that, the appropriate ratio of concentration to form the silicon nanowires obeyed the [HF]/[H2O2]  = R equation when R= 2.5, 3 and 3.5 and any deviation of these ratio, cause to destruction of wire-like structure. Moreover, the critical etching rates to form the SiNWs are in the range of 4nm/s to 5nm/ s.