Electronic properties of chemically doped graphene

Chemical doping of graphene is the most robust way of modifying graphene's electronic properties. We review here the results obtained so far on the electronic structure and transport properties of chemically doped graphene, focusing on the results obtained with scanning tunneling microscopy/spectroscopy (STM/S), angle-resolved photoemission spectroscopy (ARPES), and magnetoresistance measurements. The majority of the results reported have been obtained on nitrogen-doped samples, but boron-doped graphene has also been well documented. Aside from the appearance of the dopant on STM topographic images, the main questions that have been addressed are the atomic configurations of the doping and their doping efficiency (number of electrons/holes brought to the graphene lattice). Both can be addressed by a local probe such as STM/S. The doping efficiency has also been complementarily studied via direct visualization of the band structure with ARPES. The effect of the dopants on the electronic transport properties and in particular their influence on the scattering mechanisms is also presented. Finally, avenues for future research efforts are suggested.