New research has shown that graphene ribbons can be formed by irradiating the surface of a bulk graphite crystal with a single laser pulse1. This technique may provide a cheap and simple way of making graphene ribbons for use in various electronic devices.
Electrons travel through graphene without scattering. As a result, electrons encounter no resistance, and no energy dissipation occurs in the conduction channel. These electronic properties can be tuned from semimetallic to semiconducting by reducing the graphene sample's lateral dimensions to a few tens of nanometres.
Existing techniques for producing graphene ribbons are time-consuming and expensive. In addition, such techniques employ two or more laser beams that require the use of complex optical instruments. To devise a cheap and simple alternative method, the researchers delivered a single laser beam through a commercial CD containing an array of parallel lines with a width of 1 μm, a spacing of 500 nm and a height of 180 nm. The CD was placed in contact with a highly oriented pyrolytic graphite (HOPG) surface.
A single laser pulse was sufficient to produce ribbon-like patterns of the CD on the HOPG surface. The researchers then transferred the graphene ribbons onto a silica surface using polydimethylsiloxane (PDMS).
Most of the transferred ribbons contained either a few layers (thickness of <3 nm) or multiple layers (thickness of 30–40 nm). The ribbons were several micrometres long and had a width of around 1 μm. A CD, DVD or any similar media can be used to create graphene ribbons on the HOPG surface. The CD material — polycarbonate — absorbs wavelengths only below 300 nm, which allows the use of optical and ultraviolet lasers.
The researchers say that this technique can also be used on surfaces such as metals, semiconductors and insulators.
