title: Control of shape and material composition of solid-state nanopores.
abstract: Solid-state nanopores fabricated by a high-intensity electron beam in ceramic membranes can be fine-tuned on three-dimensional geometry and composition by choice of materials and beam sculpting conditions. For similar beam conditions, 8 nm diameter nanopores fabricated in membranes containing SiO(2) show large depletion areas (70 nm in radius) with small sidewall angles (55 degrees ), whereas those made in SiN membranes show small depletion areas (40 nm) with larger sidewall angles (75 degrees ). Three-dimensional electron tomograms of nanopores fabricated in a SiO(2)/SiN/SiO(2) membrane show a biconical shape with symmetric top and bottom and indicate a mixing of SiN and SiO(2) layers up to 30 nm from the edge of nanopore, with Si-rich particles throughout the membrane. Electron-energy-loss spectroscopy (EELS) reveals that the oxygen/nitrogen ratio near the pore depends on the beam sculpting conditions.
authors.affiliation: Kavli Institute of Nanoscience, Delft University of Technology, Lorentzweg 1, 2628 CJ Delft, The Netherlands.
authors.forename: Meng-Yue
authors.initials: MY
authors.lastname: Wu
authors.forename: Ralph M M
authors.initials: RM
authors.lastname: Smeets
authors.forename: Mathijs
authors.initials: M
authors.lastname: Zandbergen
authors.forename: Ulrike
authors.initials: U
authors.lastname: Ziese
authors.forename: Diego
authors.initials: D
authors.lastname: Krapf
authors.forename: Philip E
authors.initials: PE
authors.lastname: Batson
authors.forename: Nynke H
authors.initials: NH
authors.lastname: Dekker
authors.forename: Cees
authors.initials: C
authors.lastname: Dekker
authors.forename: Henny W
authors.initials: HW
authors.lastname: Zandbergen
mesh_terms: 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; D044367:Phase Transition; D016062:Porosity; D017655:Silicon Compounds / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties
chemical_list: D046911:Macromolecular Substances; D017655:Silicon Compounds; D012822:Silicon Dioxide; C032734:silicon nitride