Graphene has been touted as the new wonder material for electronics. As we have observed earlier, the excitement is due to the extraordinarily high carrier mobilities, among other interesting properties . Unfortunately, graphene has no band gap, so it must be chemically or physically modified to become a useful semiconductor.
Chemical doping is developing apace, with electron donors (like alkali metals)  and hole donors (like bismuth and gold)  now experimentally established. Equally interesting is hydrogen “doping” (see references in ), realized by reacting graphene with hydrogen. This reaction has generally been carried out globally, but it occurs to me that one might use beam technology to drive localized reactions: proton beam, atomic hydrogen beam, or e-beam induction à la Zeiss MeRiT. All these procedures result in simultaneously splitting the valence and conduction bands and moving the fermi level.
Very recently, Chen’s group at Purdue reports a solid-state reaction under 30 kV e-beam bombardment of graphene on a substrate . This reaction likewise modifies the band structure. (The authors claim that the dose, ~1800 μC / cm^2, is “typical” SEM exposure.)
Physically restructuring graphene also results in changes to its electrical properties, due to edge states (akin to surface states in 3-dimensional materials). Extremely high e-beam doses (~30 C / cm^2 at 200 kV) result in material removal from the beam impact point. Drndić’s group reports  creating holes and lines in suspended graphene by this method. The review by Krasheninnikov and Nordlund  is a highly valuable resource in regard to such physical restructuring of materials. The shorter review , also by Krasheninnikov, focuses on carbon materials.
 Berashevich, Chakraborty, “Graphene and graphane: New stars of nanoscale electronics”, arXiv:1003.0044.
 Gierz, et al., “Atomic Hole Doping of Graphene”, arXiv:0808.0621.
 Ohta, et al., “Controlling the Electronic Structure of Bilayer Graphene”, Science 313, 951 (2006).
 Childres, et al., “Effect of electron-beam irradiation on graphene field effect devices”, arXiv:1008.4561.
 Fischbein, Drndić, “Electron Beam Nanosculpting of Suspended Graphene Sheets”, arXiv:0808.2974.
 Krasheninnikov, Nordlund, “Ion and electron irradiation-induced effects in nanostructured materials”, J Appl Phys 107, 071301 (2010).
 Krasheninnikov, Banhart, “Engineering of nanostructured carbon materials with electron or ion beams”, Nature Materials, 6 (2007) 723-33.