Effective patterning and cleaning of graphene by plasma etching and block copolymer lithography for nanoribbon fabrication

At a sub-20 nm resolution, patterning 2D materials is necessary in a large number of applications to enhance or control the overall material and device properties. In this work, the authors present their results on the fabrication of graphene nanoribbons using a block copolymer thin film as a lithography mask. A special emphasis is given to the development of new plasma etching processes to pattern graphene and to chemically clean the fabricated nanostructures. At the end, clean 10 nm wide graphene nanoribbons are obtained as confirmed by Raman spectroscopy, x-ray photoelectron spectroscopy, atomic force microscopy, and SEM characterizations. Block copolymer lithography and proper plasma etching conditions allow for easier graphene patterning on a large area and low-cost processing.