FIB carving of nanopores into suspended graphene films

In this article we report on carving nanopores into suspended graphene sheets using a finely focused and shaped gallium ion beam. We show that in addition to serving as a nearly ideal substrate for high resolution patterning, suspended graphene can be patterned with high accuracy using a methodology that is described. Furthermore, shapes and dimensions of the fabricated nanopores were investigated, showing stable structures that do not follow the circular shape of the FIB probe. These results highlight the role of preferential engraving directions during the carving process of the graphene material. We conclude in confirming the highly insulating properties of such graphene when immersed in an ionic solution, which is of particular interest for experiments such as DNA translocation.