title: Self-assembly and nanosphere lithography for large-area plasmonic patterns on graphene.
abstract: Plasmonic structures on graphene can tailor its optical properties, which is essential for sensing and optoelectronic applications, e.g. for the enhancement of photoresponsivity of graphene photodetectors. Control over their structural and, hence, spectral properties can be attained by using electron beam lithography, which is not a viable solution for the definition of patterns over large areas. For the fabrication of large-area plasmonic nanostructures, we propose to use self-assembled monolayers of nanospheres as a mask for metal evaporation and etching processes. An optimized approach based on self-assembly at air/water interface with a properly designed apparatus allows the attainment of monolayers of hexagonally closely packed patterns with high long-range order and large area coverage; special strategies are devised in order to protect graphene against damage resulting from surface treatment and further processing steps such as reactive ion etching, which could potentially impair graphene properties. Therefore we demonstrate that nanosphere lithography is a cost-effective solution to create plasmonic patterns on graphene.
authors.affiliation: Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland. Electronic address: lotito@biomed.ee.ethz.ch.
authors.forename: Valeria
authors.initials: V
authors.lastname: Lotito
authors.affiliation: Laboratory of Biosensors and Bioelectronics, Institute for Biomedical Engineering, ETH Zurich, Gloriastrasse 35, 8092 Zurich, Switzerland.
authors.forename: Tomaso
authors.initials: T
authors.lastname: Zambelli
mesh_terms: D006108:Graphite / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D054118:Nanospheres / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods*; D012825:Silicon / Q000737:chemistry*; D020349:Surface Plasmon Resonance; D013499:Surface Properties
chemical_list: D006108:Graphite; D012825:Silicon
keywords: Colloidal lithography; Graphene; Nanosphere lithography; Plasmonic structures; Self-assembly