Water mask enables graphene 'nanoribbon' etching

The surreptitious discovery by Vera Abramova and co-author Alexander Slesarev, both graduate students in the lab of Rice chemist James Tour, appears online this month in the American Chemical Society journal ACS Nano.

A quantity of water adsorbed from the atmosphere was found to act as a mask in a process that begins with the creation of patterns via lithography and ends with very long, very thin graphene nanoribbons. The ribbons form wherever water gathers at the wedge between the raised pattern and the graphene surface.

The water formation is called a meniscus; it is created when the surface tension of a liquid causes it to curve. In the Rice process, the meniscus mask protects a tiny ribbon of graphene from being etched away when the pattern is removed.

In a statement Tour said any method to form long wires only a few nanometres wide should catch the interest of microelectronics manufacturers.

‘They can never take advantage of the smallest nanoscale devices if they can’t address them with a nanoscale wire,’ he said. ‘Right now, manufacturers can make small features, or make big features and put them where they want them. But to have both has been difficult. To be able to pattern a line this thin right where you want it is a big deal because it permits you to take advantage of the smallness in size of nanoscale devices.’