Nonlinear optical properties of nitrogen-doped bilayer graphene

Abstract

The electronic properties of graphene can be controlled by substitutional doping to obtain p-type or n-type characteristics. To this end, bilayer graphene films are synthesized using CVD method and substitutionally doped with Nitrogen (N). Previously, XPS measurements done in tandem with Raman spectroscopy revealed that the rich chemistry between carbon and nitrogen can result in pyridinic, pyrrolic, or graphitic con¿JXUDWLRQV The nonlinear optical properties (NLO) of both pristine and N-doped graphene samples are studied in both nanosecond and femtosecond excitation regimes using open aperture Z-scan method. Similar to the previous observations with Raman spectroscopy, we see that the NLO properties are more sensitive to the local bonding environments which determine the defect density in the graphene lattice, rather than just the dopant percentage. Our results give more insights into the effect of defects on the NLO properties of doped graphene which help in tailor making graphene samples for applications like modelocking and optical switching.

Nonlinear optical effects in nitrogen-doped graphene

“…2b) consists of three peaks, which indicates that the N 24 The Raman spectrum of N-doped graphene is shown in Fig. 3 and is very similar to those reported by Anand et al 25 The N doping creates a large amount of topological defects, and the sp 2 C of these defects induces the much stronger D band Raman peak at $1330 cm À1 . On the contrary, for pure graphene, this peak is very faint.…”

“…On the contrary, for pure graphene, this peak is very faint. 25 Thus, the obvious D band Raman peak in Fig. 3 reects the effective N doping and the increasing of lattice disorder.…”