A large-area 15 nm graphene nanoribbon array patterned by a focused ion beam

Using a focused ion beam, we patterned epitaxial graphene on SiC into an array of graphene nanoribbons as narrow as 15 nm by optimizing the Ga(+) ion beam current, acceleration voltage, dwell time, beam center-to-center distance and ion dose. The ion dose required to completely etch away graphene on SiC was determined and compared with the Monte Carlo simulation result. In addition, a photodetector using an array of 300 20 nm graphene nanoribbons was fabricated and its photoresponse was studied.