Direct patterning of negative nanostructures on self-assembled monolayers of16-mercaptohexadecanoic acid on Au(111) substrate via dip-pen nanolithography

Abstract

Both bare and self-assembled monolayer (SAM) protected gold substrate could be etchedby allyl bromide according to atomic force microscopy (AFM), x-ray photoelectronspectroscopy (XPS) and inductively coupled plasma mass spectrometric (ICPMS) analysisresults. With this allyl bromide ink material, negative nanopatterns could be fabricateddirectly by dip-pen nanolithography (DPN) on SAMs of 16-mercaptohexadecanoic acid(MHA) on Au(111) substrate. A tip-promoted etching mechanism was proposed wherethe gold-reactive ink could penetrate the MHA resist film through tip-induceddefects resulting in local corrosive removal of the gold substrate. The fabricationmechanism was also confirmed by electrochemical characterization, energy dispersivespectroscopy (EDS) analysis and fabrication of positive nanopatterns via a used DPNtip.