Interference lithographically defined and catalytically etched, large-area silicon nanoconesfrom nanowires

Abstract

We report a simple and cost effective method for the synthesis of large-area, preciselylocated silicon nanocones from nanowires. The nanowires were obtained fromour interference lithography and catalytic etching (IL-CE) method. We foundthat porous silicon was formed near the Au catalyst during the fabrication ofthe nanowires. The porous silicon exhibited enhanced oxidation ability whenexposed to atmospheric conditions or in wet oxidation ambient. Very well locatednanocones with uniform sharpness resulted when these oxidized nanowires wereetched in 10% HF. Nanocones of different heights were obtained by varying thedoping concentration of the silicon wafers. We believe this is a novel method ofproducing large-area, low cost, well defined nanocones from nanowires both interms of the control of location and shape of the nanocones. A wide range ofpotential applications of the nanocone array can be found as a master copy fornanoimprinted polymer substrates for possible biomedical research; as a candidate formaking sharp probes for scanning probe nanolithography; or as a building block forfield emitting tips or photodetectors in electronic/optoelectronic applications.