Opal chips: vectorial growth of colloidal crystal patterns inside silicon wafers

Abstract
A simple, quick, reproducible and inexpensive method is described that combines self-assembly, micro-fluidics and soft lithography, to achieve a novel example of vectorial control of thickness, area, orientation and registry of patterned single crystal silica colloidal crystals in silicon wafers, coined opal chips, for potential applications in photonic chip and lab-on-chip technologies.