Insight into macroscopic metal-assisted chemical etching for silicon nanowires

To understand the principles of the fabrication of nanowire arrays using macroscopic metal-assisted chemical etching (MACE), Si nanowires (SiNWs) are synthesized using Ag-coated Si substrates and Pt electrodes by the macroscopic MACE. Analysis of the SiNWmorphology coupled with the corresponding current density in the MACE process is applied to systematically investigate the effects of the electrical connection, Ag coating, etching conditions, Si substrates, and light irradiation on the formation of SiNWs. It is found that there is a certain relationship between the current density and the SiNWlength. Amode is proposed to fundamentally understand the mechanisms of the preparation of SiNWs using MACE. Associated opportunities are also discussed.