The effect of atmospheric doping on pressure-dependent Raman scattering in supported graphene.

Egor A Kolesov,Tae Won Kang,Olga V Korolik,Hak Dong Cho,Gennady N Panin,Olesya O Kapitanova,Mikhail S Tivanov,Xiao Fu

doi:10.3762/bjnano.9.65

Abstract

Atmospheric doping of supported graphene was investigated by Raman scattering under different pressures. Various Raman spectra parameters were found to depend on the pressure and the substrate material. The results are interpreted in terms of atmospheric adsorption leading to a change in graphene charge carrier density and the effect of the substrate on the electronic and phonon properties of graphene. It was found that adsorption of molecules from the atmosphere onto graphene doped with nitrogen (electron doping) compensates for the electron charge. Furthermore, the atmosphere-induced doping drastically decreases the spatial heterogeneity of charge carriers in graphene doped with nitrogen, while the opposite effect was observed for undoped samples. The results of this study should be taken into account for the development of sensors and nanoelectronic devices based on graphene.

Highlights

Graphene is a promising material for a variety of applications due to its unique physical properties [1]
The purpose of this study is to investigate the pressure-dependent behavior of the density of charge carriers in graphene and the effect of the substrate on the adsorption properties of graphene at pressures below atmospheric pressure
For doped graphene (1.11% of nitrogen from XPS data), the D band intensity increases compared to pristine graphene, the second disorder-induced peak becomes evident, the G peak position is upshifted by ≈3 cm−1, while the 2D peak is about normal, naturally indicating electron doping together with I2D/IG values of 1.4–1.6 [13]

Summary

Introduction

Graphene is a promising material for a variety of applications due to its unique physical properties [1]. Among its other outstanding features, one can distinguish its strong sensitivity to adsorbates, leading to a huge number of potential graphene applications in biosensors [2]. Atmospheric adsorption is known to affect graphene charge carrier density, leading to gradual self-sustained hole doping [3]. Adsorption can be an extremely undesirable effect when a nanoelectronic device is designed to operate on the basis of undoped properties of graphene; on the other hand, the adsorption of certain functional groups, for example, can be used as a constituent part of the methods of graphene functionalization [4].

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Conclusion