Colloidal lithography--the art of nanochemical patterning.

Nanochemical printmaking: Colloidal lithography paves a powerful nanochemical way for patterning on planar substrates and microparticles. The feature size can easily be scaled down to 100 nm by reducing the diameter of the microspheres and the feature shape diversified by the crystalline structure of a colloidal crystal mask, the mask etching time, the incidence angle of the vapor beam, and the mask registry (the azimuth angle of the vapor beam). Colloidal lithography relies on using colloidal crystals as masks for etching and deposition, and allows fabrication of various nanostructures on planar and non-planar substrates with low-cost, high-throughput-processing, large fabrication area, and a broad choice of materials. The feature size can easily shrink by decreasing the microsphere diameter in the colloidal mask. The feature shape can be diversified by varying the crystal structure of the colloidal mask, etching the mask, altering the incidence angle of the vapor beam, and stepwise manipulation of the mask registry. This nanochemical patterning strategy paves a complementary way to conventional top-down lithography. This focus review provides an overview of the principle of colloidal lithography, and surveys the recent developments as well as outlining the future challenges.