title: Maskless fabrication of nanowells using chemically reactive colloids.
abstract: This letter describes the maskless fabrication of nanowells on a silicon substrate using chemically reactive nanoparticles. The amidine-functionalized polystyrene latex (APSL) colloids are adhered onto a silicon wafer, and hydrolysis of the particles' amidine groups generates the ammonium hydroxide etchant locally. The localized release of reactive species and its fast diffusion into the bulk liquid ensure that the silicon etching takes place only under the APSL colloids. Thus, the basal length of the nanowells is precisely controlled by the diameter of the APSL particles. The shape of the nanowells depends on the structure of the substrate: inverted pyramids on silicon (100) and hexagonal pits on silicon (111). The method described here provides an easy, inexpensive, safe, and high-throughput approach for generating nanowells on silicon surfaces. This maskless and simple nanofabrication method will open doors for new applications with locally generated or locally delivered chemistry from nanoparticles.
authors.affiliation: Department of Chemical Engineering, Pennsylvania State University , University Park, Pennsylvania 16802, USA.
authors.forename: Neetu
authors.initials: N
authors.lastname: Chaturvedi
authors.forename: Erik
authors.initials: E
authors.lastname: Hsiao
authors.forename: Darrell
authors.initials: D
authors.lastname: Velegol
authors.forename: Seong H
authors.initials: SH
authors.lastname: Kim
mesh_terms: D003102:Colloids / Q000737:chemistry*; D003460:Crystallization / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D036103:Nanotechnology / Q000379:methods*; D010316:Particle Size; D013499:Surface Properties
chemical_list: D003102:Colloids; D046911:Macromolecular Substances