Whenever I consider the possibilities of dip-pen nanolithography (DPN), I always think of that Xerox commercial from the 1970s in which after toiling for incalculable hours of transcribing a text a monk presents his work to the chief monk who is impressed but asks for 500 more copies.
Let’s face it, taking the tip of an Atomic Force Microscope (AFM) and dipping it into a sort of molecular ink and then drawing patterns on a substrate may be exact but it’s not exactly a fast process.
That understood, I was intrigued by recent work researchers at Stanford University were doing with DPN in creating graphene devices. To date, electron-beam lithography (EBL) has been used for constructing such devices.
The research, which was originally published in the journal ACS Nano, showed that an AFM could be used for creating graphene devices thereby replacing EBL techniques and eliminating some of the inherent problems of working with EBL such as exposing the graphene to electron irradiation.
"DPN has several advantages over EBL, such as no damage from electron irradiation and the ability to pattern nanostructures and image them using one system operating under ambient conditions," Maria Wang, the first author of the research, told Nanowerk. "We have demonstrated that dip-pen nanolithography can be used to create arbitrarily shaped graphene devices for nanoelectronics and identified the process steps that may affect their electrical characterization."
To address issues of scalability, which I facetiously referred to with Xerox commercial, Wang also points out that the DPN process could be done with multipen arrays, establishing a kind of parallel fabrication.
"Parallel fabrication of individual graphene devices using DPN could potentially result in higher yield and faster processing times than serial fabrication using EBL,” suggests Wang. “This increase in fabrication efficiency could potentially accelerate graphene research."
Dexter Johnson is a contributing editor at IEEE Spectrum, with a focus on nanotechnology.