A Direct‐Write Single‐Step Positive Etch Resist for Dip‐Pen Nanolithography

Dip-pen nanolithography is used to deposit 1-octadecylamine (ODA) as a positive etch resist on gold substrates and then passivate the unpatterned regions with 1-octadecanethiol (ODT). Selective etching of the ODA-patterned features is achieved to generate nanoholes without the need for any electrochemical desorption steps (see image). Patterns are formed due to the faster etching rates of the ODA-patterned areas compared with the ODT-covered regions in a thiourea and ferric nitrate etching solution.