Spectroscopic characterization of nitrogen- and boron-doped graphene layers

Nitrogen- and boron-doped graphene layers were grown on copper substrates by alcoholic chemical vapor deposition and characterized by Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and electrical transport measurements. The growth of high-quality monolayer graphene was confirmed by micro-Raman spectroscopy. The G and 2D peaks showed systematic frequency shift and broadening with the impurity concentration. The G peaks showed Fano-like asymmetric line shapes. These behaviors suggested the generation of free carriers by doping. XPS and electrical transport measurements also supported the systematic incorporation of impurities in graphene layers. (C) 2015 The Japan Society of Applied Physics