Fabrication of nitrogen-doped graphenes by pulsed laser deposition and improved chemical enhancement for Raman spectroscopy

In this letter, we report the in situ growth of N-doped graphene (NG) thin films by ultraviolet pulsed laser deposition (PLD) in the presence of nitrogen. Based on this approach, the concentration of nitrogen-doping can be easily controlled via the nitrogen gas pressure during the PLD process. XPS results confirm that the nitrogen atoms have been successfully doped into graphene lattice. Moreover, the NGs show improved chemical enhancement for Raman spectra of absorbed Rhodamine 6G (R6G) molecules as compared to the pristine graphene (PG). The relative enhancement factor varies with the nitrogen content in the graphene, and the maximum value is about 2.5. The results show that the NG is a promising material for applications in chemical and biological detection because of its excellent enhanced Raman scattering performance.