The fabrication of long-range ordered nanocrescent structures based on colloidal lithography and parallel imprinting.

A method for fabricating nanocrescent structures is presented based on a combination of colloidal lithography and parallel imprinting. In this process, non-close-packed colloidal spheres were prepared by a simple lift-up soft lithography technique, and subsequently the individual particles were used as shadow masks to angle deposit a layer of silver on the silicon substrates. Then, the silver-coated samples were etched to get silicon crescent nanohole arrays, which served as templates to mold patterned photocurable resin membranes. The patterned photocurable resin membranes were used to print gold nanocrescent nanostructures onto glass substrates. The size of the opening and the width of the gold nanostructures could be freely adjusted by changing the azimuth angle and tilt angle. Very importantly, the central angle of the nanocrescents could be adjusted in the range of 0°-360°. This method provides a low-cost and highly reproducible way to prepare complex nanostructure arrays for applications related to near field enhancement materials, optical sensors and surface-enhanced Raman spectroscopy, etc.