Fabrication of nonspherical colloidal particles via reactive ion etching of surface-patterned colloidal crystals

We have created multilayered nonspherical colloidal particles by reactive ion etching (RIE) of surface-patterned colloidal crystals. The effectiveness of the Au patterns as etching masks in defining and controlling the particle morphologies depend on their relative dimensions to the particles and the RIE conditions. As a result, nonspherical particles with shape and size more diversiform and controllable than those obtained via RIE of pure colloidal crystals were fabricated. This approach can be applied to a wide of particles (ceramic, metal, semiconductor) as long as the selective RIE between the masks and particles is afforded, which definitely provides a facile and controllable route to produce nonspherical particles of various morphologies. Furthermore, we demonstrated that the patterned particles could be used as templates for fabricating novel nanostructures.