Self-assembly and nanofabrication approaches towards photonics and plasmonics: Part I: Directed assembly of inorganic nanostructures through chemical and biomimetic templating. Part II: Fabrication of plasmon resonant structures for surface-enhanced sensing and fluorescence.

摘要

Applications of inorganic nanostructures in sensing and optoelectronics are limited by the methods currently available to spatially organize them into desired configurations on solid supports. To address these challenges, a method combining "top-down" lithography and "bottom-up" self-assembly was employed to fabricate nanostructured systems using organic, inorganic and biological building blocks. Lithographic techniques, such as electron beam, colloidal and soft lithography, were used to pattern functional organic molecules and genetically engineered peptides on Au, SiO2/Si, mica and glass substrates with feature sizes ranging from sub-100nm to microscale over a large surface area (1--5 cm2). These surfaces present chemical functionalities or biomolecular recognition to direct the self-assembly of Au nanoparticles and CdSe-ZnS core-shell quantum dots into well-defined arrays in a site-specific, parallel manner. In addition to the lateral ordering imposed by these templates, placement of quantum dots on patterned Ag and Au nanostructures was controlled vertically through layer-by-layer assembly of molecular spacers. This allowed the construction of tunable arrays of quantum dots with surface-plasmon-enhanced fluorescence. In addition to the directed self-assembly of inorganic nanostructures, a novel nanofabrication technique was also developed to generate a new class of periodically arrayed plasmon resonant structures with unique topographical characteristics for ultra-sensitive surface-enhanced molecular sensing.