title: Nanocavity crossbar arrays for parallel electrochemical sensing on a chip.
abstract: We introduce a novel device for the mapping of redox-active compounds at high spatial resolution based on a crossbar electrode architecture. The sensor array is formed by two sets of 16 parallel band electrodes that are arranged perpendicular to each other on the wafer surface. At each intersection, the crossing bars are separated by a ca. 65 nm high nanocavity, which is stabilized by the surrounding passivation layer. During operation, perpendicular bar electrodes are biased to potentials above and below the redox potential of species under investigation, thus, enabling repeated subsequent reactions at the two electrodes. By this means, a redox cycling current is formed across the gap that can be measured externally. As the nanocavity devices feature a very high current amplification in redox cycling mode, individual sensing spots can be addressed in parallel, enabling high-throughput electrochemical imaging. This paper introduces the design of the device, discusses the fabrication process and demonstrates its capabilities in sequential and parallel data acquisition mode by using a hexacyanoferrate probe.
authors.affiliation: Institute of Bioelectronics (PGI-8/ICS-8) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany. Current address: Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom.
authors.forename: Enno
authors.initials: E
authors.lastname: Kätelhön
authors.affiliation: Institute of Bioelectronics (PGI-8/ICS-8) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Dirk
authors.initials: D
authors.lastname: Mayer
authors.affiliation: Institute of Bioelectronics (PGI-8/ICS-8) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany.
authors.forename: Marko
authors.initials: M
authors.lastname: Banzet
authors.affiliation: Institute of Bioelectronics (PGI-8/ICS-8) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany ; Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Offenhäusser
authors.affiliation: Institute of Bioelectronics (PGI-8/ICS-8) and JARA-Fundamentals of Future Information Technology, Forschungszentrum Jülich, 52425 Jülich, Germany ; Institute of Physics, RWTH Aachen University, 52074 Aachen, Germany.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Wolfrum
keywords: electrochemical imaging; nanoelectrochemistry; redox cycling