A team at the Department of Energy’s Oak Ridge National Laboratory and North Carolina State University has found a way to grow narrow ribbons of graphene without the use of metal substrates.

Narrow graphene ribbons can perform as a semiconductor if the ribbons are made with a specific edge shape, but to grow graphene nanoribbons with controlled width and edge structure from polymer precursors, is not a simple task. Previous researchers had used a metal substrate to catalyse a chemical reaction, but the metal substrate suppresses useful edge states and shrinks the desired band gap. The team in this work managed to grow graphene nanoribbons without a metal substrate. Instead, they injected charge carriers that promote a chemical reaction that converts a polymer precursor into a graphene nanoribbon.

According to the researchers, the technique could provide the basis for an electronic device that could carry current with virtually no resistance, even at room temperature. “It’s a way to tailor physical properties for energy applications,” they said. “This is an excellent example of direct writing. You can direct the transformation process at the molecular or atomic level.” Plus, the process could be scaled up and automated.