Nanofabrication – European Research Labs Apply Dip Pen Nanolithography

Dip Pen Nanolithography® (DPN®) came to light as a novel research tool back in 1999 with a paper in Science from the a group at Northwestern University in the USA (1). Like many new technologies, the early development work was dedicated to understanding the fundamental strengths and weaknesses of the technique. Once DPN spread to other labs with more diverse research interests, DPN become an important tool that is now being used to solve some long-standing problems regarding nanoscale device fabrication. This paper will highlight some ofthese solutions by looking at three European research labs.

SO WHAT IS DPN?
Dip Pen Nanolithography (DPN) is an established method of nanofabrication in which materials are deposited onto a surface via a sharp tip. Molecules are typically transferred from the tip to the surface through a water meniscus which forms in ambient conditions as the tip nears the surface.

DPN enables controlled deposition of a variety of nanoscale materials onto many different substrates. The vehicle for deposition can include pyramidal scanning probe microscope tips, hollow tips, and even tips on thermally actuated cantilevers. Recent advances have demonstrated scalability of the technique with arrays of tips leading to true massive parallelisation with up to 55,000 tips.

The controlled transfer of a molecular ’ink’ from a coated nanoscale tip to a substrate was described and initially developed by a research group at Northwestern University led by Professor Chad Mirkin. Analogous to the macro technique of a quill pen, these authors introduced the term Dip-Pen Nanolithography or DPN to describe their work.