Novel fabrication of extremely high aspect ratio and straight nanogap and array nanogap electrodes

We reported a reproducible, simple and novel method for fabricating electrodes with high aspect ratio and highly straight nanometer size gap. The gap size could be controlled in a wide range between several nm up to several hundreds of nm, although in this work our individual gap size was 172 nm. In this method a single nanofiber was aligned as a sacrificial structure using a secondary electrical field and its diameter lowered through thermal treatment to obtain smallest gap size. Then, after deposition of blanket metal, nanofiber was removed obtaining nano scale gap. We predict the application of these simple fabricated gaps for diverse fields. The expensive, time consuming, none-reproducible and low accuracy fabrication methods can supersede by this cost effective, facile and fast method. It can provide mass production for precisely positioned nanoscale gaps, ignoring electrode and substrate materials. The electrodes hold the advantage of maximum straightness comparing to other similar nano fabrication methods. Fabricated gaps have large aspect ratio (in the order of 10⁶). Also array gaps with average gap size of 400 nm were fabricated. Same size gaps could be fabricated in a row by this method. Different parameters in alignment were taken into account and studied. The process shows great potential for facile and batch fabrication of parallel submicron gaps for diverse applications including gas sensing, bio-sensing and nanofluidic systems.