The gas field ion source (GFIS) can be used to generate beams of helium, neon, hydrogen, and nitrogen ions, among others. Due to the low energy spread and the atomically small virtual source size, highly focused ion beams (FIB) can be obtained. We discuss the history of the GFIS and explain the field ionization and field evaporation process in general. Then, the unique properties of the nitrogen ionization, originating from the molecular nature, are explained. We show how the nitrogen ion microscopy (N2IM) can be used to image and pattern samples. The unique contrast observed in samples with graphene or carbon is reported. Finally, we conclude with an outlook of the technology and possible key applications such as spatially localized nitrogen-vacancy center implantation.
Part of the book: Ion Beam Applications