A continuous process for Si nanowires with prescribed lengths

A simple top-down approach for the continuous mass preparation of single crystalline silicon nanowires (SiNWs) with controlled lengths was developed. The approach is based on periodic pulsing of anodic bias during gold-assisted chemical etching of a silicon substrate and subsequent ultrasonic treatment of the resulting porosity-patterned SiNWs for selective breakage of nanowires at the porous segments, and allows us to overcome some of the drawbacks in conventional bottom-up methods for SiNW growth.