Dip Pen Nanolithography of Conductive Silver Traces

Abstract

We report the first demonstration of subμm, sub-50-μΩ·cm conductive traces directly written by Dip Pen Nanolithography (DPN). We achieved subμm Ag lines with 28.8 μΩ·cm average resistivity after direct-write printing from a silver nanoparticle-based ink suspension and annealing at 150 °C for 10 min. This compares to Ag bulk resistivity of 1.63 μΩ·cm, where the difference is within the range of previously reported variations in conductivity of Ag-based inks due to annealing conditions and larger width scales. We leveraged DPN’s ability to directly place materials at specific locations in order to fabricate and characterize these conductive silver (Ag) traces on electrode patterns and multiple substrates (SiO2, Kapton, mica). The low viscosity of the AgNP ink solution allowed write speeds up to 1600 μm/s, almost 4 orders of magnitude higher than typical thiol-on-gold DPN writing speeds. This direct-write methodology paves the way for site-specific deposition of metallic materials for use in applications such as circuit repair, sensor element functionalization, failure analysis, gas sensing, and printable electronics.