title: Lift-Off Free Fabrication Approach for Periodic Structures with Tunable Nano Gaps for Interdigitated Electrode Arrays.
abstract: We report a simple, low-cost and lift-off free fabrication approach for periodic structures with adjustable nanometer gaps for interdigitated electrode arrays (IDAs). It combines an initial structure and two deposition process steps; first a dielectric layer is deposited, followed by a metal evaporation. The initial structure can be realized by lithography or any other structuring technique (e.g., nano imprint, hot embossing or injection molding). This method allows the fabrication of nanometer sized gaps and completely eliminates the need for a lift-off process. Different substrate materials like silicon, Pyrex or polymers can be used. The electrode gap is controlled primarily by sputter deposition of the initial structure, and thus, adjustable gaps in the nanometer range can be realized independently of the mask or stamp pattern. Electrochemical characterizations using redox cycling in ferrocenemethanol (FcMeOH) demonstrate signal amplification factors of more than 110 together with collection factors higher than 99%. Furthermore, the correlation between the gap width and the amplification factor was studied to obtain an electrochemical performance assessment of the nano gap electrodes. The results demonstrate an exponential relationship between amplification factor and gap width.
authors.affiliation: Vorarlberg University of Applied Sciences , 6850 Dornbirn, Austria.|Department of Microsystem Engineering (IMTEK), University of Freiburg , 79110 Freiburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Partel
authors.affiliation: Department of Microsystem Engineering (IMTEK), University of Freiburg , 79110 Freiburg, Germany.|Freiburg Materials Research Center (FMF), University of Freiburg , 79104 Freiburg, Germany.
authors.forename: Can
authors.initials: C
authors.lastname: Dincer
authors.affiliation: Vorarlberg University of Applied Sciences , 6850 Dornbirn, Austria.
authors.forename: Stephan
authors.initials: S
authors.lastname: Kasemann
authors.affiliation: Department of Microsystem Engineering (IMTEK), University of Freiburg , 79110 Freiburg, Germany.
authors.forename: Jochen
authors.initials: J
authors.lastname: Kieninger
authors.affiliation: Vorarlberg University of Applied Sciences , 6850 Dornbirn, Austria.
authors.forename: Johannes
authors.initials: J
authors.lastname: Edlinger
authors.affiliation: Department of Microsystem Engineering (IMTEK), University of Freiburg , 79110 Freiburg, Germany.|Freiburg Materials Research Center (FMF), University of Freiburg , 79104 Freiburg, Germany.
authors.forename: Gerald
authors.initials: G
authors.lastname: Urban
keywords: amperometric biosensor; electrochemical impedance spectroscopy; interdigitated electrode array; lift-off free fabrication; redox cycling; tunable nano gaps