Solvent-induced formation of unidirectionally curved and tilted Si nanowires during metal-assisted chemical etching

Abstract

We present a new approach for inducing the formation of unidirectionally slanted or curved silicon nanowires (SiNWs) via metal-assisted chemical etching by introducing various co-solvents to the etching solution. The effects of adding methanol, ethanol, 2-propanol, and acetonitrile to the HF–H₂O₂–H₂O system are studied. It is demonstrated that simply by controlling the type and the amount of co-solvent, such wires can be fabricated over a large area and the wire curvature can be tuned.