An innovative approach for the high-throughput, rapid, and low-cost fabrication of ultranarrow graphene nanoribbons (GNRs) using nanosphere lithography (NSL) nanopatterning in combination with low-power O2 plasma etching is presented. The intrinsic simplicity of NSL patterning enables this fabrication approach to be applicable for the straightforward on-chip fabrication of GNRs and bandgap tuning of graphene.
The narrow graphene ribbons prepared using this technique exhibit a bandgap, which could make them useful in electronic components such as transistors. Wang and his colleagues demonstrated this utility by constructing a transistor from a graphene sheet and then gradually etching the graphene using their polystyrene bead-based process. The transistor, which did not display transistor function before etching, showed good transistor functionality after etching for just 30 seconds, achieving an on–off ratio of 90 for current switching. The conductivity of the graphene transistor channel was reduced by a factor of about 1,000 times by the etching process.
The fabrication technique is relatively simple and inexpensive, is capable of forming many graphene nanoribbons at the same time, and can even be used to modify finished devices. Future work will include research to understand the effects of the etching process on the ribbon edges, where atomic disorder can strongly affect the device’s electrical properties.