Synthesis of nitrogen-doped graphene on copper from azafullerene

Graphene is a fascinating material with many potential applications. Doping graphene with heteroelements like nitrogen is an effective approach to improving its performance in supercapacitors, transistors, batteries, fuel cells, solar cells, sensors, and gas storage. It is always desired to develop new approaches for the synthesis of large-scale, high-quality N-doped graphene with controlled doping properties. In this research, we have achieved the synthesis of N-doped single-layer graphene on the Cu(111) surface using the N-containing sole precursor azafullerene (C59NH). The synthesis process includes cycles of precursor deposition at room temperature and subsequent annealing in ultrahigh vacuum (UHV). The synthesis process and doping properties have been investigated on the atomic scale using scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) measurements. The existence of graphitic and pyridinic N atoms in the graphene layer is suggested by STM and XPS results. For the first time, we observed the rings of N dopants, which provide valuable information about the growth process.