AgNO3-Dependent Morphological Change of Si Nanostructures Prepared by Single-Step Metal Assisted Etching Method

Abstract

The morphological changes of a nanostructured Si surface prepared by metal assisted etching were investigated. We used a mixture of silver nitrate (AgNO3) and hydrofluoric acid (HF) as an electroless plating bath of Ag, as well as an etching solution of Si. With a change in silver ion concentration in the etching solution, three types of etched Si nanostructures were observed: “nanowire”, “porous wall”, and “polished”. We developed a phase diagram of the morphology of the etched Si surface. With increasing concentration of AgNO3 in the etching solution, the surface morphology of etched Si changes from nanowire to porous wall, and finally, polished for regardless of Si resistivity.