Modification of the G-phonon mode of graphene by nitrogen doping

Authors

Pavel V. Lukashev, University of Nothern IowaFollow
Liuyan Zhao, Columbia UniversityFollow
Tula R. Paudel, University of Nebraska-LincolnFollow
Theanne Schiros, Columbia University
Noah Hurley, University of Northern Iowa
Evgeny Y. Tsymbal, University of Nebraska-LincolnFollow
Aron Pinczuk, Columbia University
Abhay Pasupathy, Columbia University
Rui He, University of Northern IowaFollow

Date of this Version

2016

Citation

APPLIED PHYSICS LETTERS 108, 041907 (2016)

http://dx.doi.org/10.1063/1.4940910

Comments

Copyright 2016 AIP Publishing LLC

Abstract

The effect of nitrogen doping on the phonon spectra of graphene is analyzed. In particular, we employ first-principles calculations and scanning Raman analysis to investigate the dependence of phonon frequencies in graphene on the concentration of nitrogen dopants. We demonstrate that the G phonon frequency shows oscillatory behavior as a function of nitrogen concentration. We analyze different mechanisms which could potentially be responsible for this behavior, such as Friedel charge oscillations around the localized nitrogen impurity atom, the bond length change between nitrogen impurity and its nearest neighbor carbon atoms, and the long-range interactions of the nitrogen point defects. We show that the bond length change and the long range interaction of point defects are possible mechanisms responsible for the oscillatory behavior of the G frequency as a function of nitrogen concentration. At the same time, Friedel charge oscillations are unlikely to contribute to this behavior.