A nanogap electrode platform for organic monolayer-film devices

The fabrication and electrical characterization of organic monolayer functionalized, planar silicon nanogap electrode devices is described. Highly doped silicon nanogap electrodes were fabricated with contact separation as small as 200 nm by anisotropic etching of silicon-on-insulator (SOI) substrates using KOH and a patterned metal film as the etch mask. Conductance was greatly improved compared to an untreated device by self-assembly of a monolayer of an aromatic organophosphonate in the nanogap. This device is a prototype for development of self-assembled monolayer-functionalized field-effect transistors involving all-silicon contact electrodes.