Templated self-assembly of sub-10 nm quantum dots

Abstract

Patterned templates can guide the self-assembly of nanoparticles into ordered arrays. Our motivation in pursuing templated self-assembly is to develop a robust method for the creation of ordered structures at length scales below ten nanometers. The basic process entails creating surface relief templates via electron-beam lithography, and spin-coating a suspension of colloidal nanoparticles onto the template. As the solvent evaporates, the quantum dots self-assemble primarily through the capillary forces created by the dewetting of the template. We demonstrate this technique at sub-10nm length scales by spin-coating a solution of organically-capped CdZnS semiconducting quantum dots onto nanopatterned grating structures on silicon substrates. We observe the geometric confinement of the quantum dots via physical templating and capillary forces into well-ordered monolayer aggregates with defined lattice orientations. While recent research has demonstrated the ability to self-assemble sub-10nm metallic nanoparticles via capillary forces into physical templates of similar size, this work is unique in the demonstration of lattice orientation control via physical templating at sub-10nm length scales.