Influence of fabrication parameters on the nanostructure of Si-NWs under HF/Fe(NO3)3 etching system

Abstract Large-area and oriented silicon nanowire arrays have been successfully fabricated through a two-step metal-assisted chemical etching process at room temperature. The effects of key fabrication parameters (AgNO 3 concentration, Fe(NO 3 ) 3 concentration, and etching time) on the silicon nanowire nanostructure were carefully investigated. The Raman spectra of silicon nanowires prepared under different etching times have been recorded and analyzed. The porosity and length of the nanowire increases with the increase in AgNO 3 concentration from 0.002 mol L −1 to 0.1 mol L −1 , which indicates that the re-dissolved Ag + ions would work as the main oxidative species and catalyze the vertical and lateral etching of nanowires, leading to silicon nanowire growth and porous structure formation.