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Atmospheric doping effects in epitaxial graphene: correlation of local and global electrical studies

V. Panchal ; C. E. Giusca ; Arseniy Lartsev (Institutionen för mikroteknologi och nanovetenskap, Kvantkomponentfysik) ; N. A. Martin ; N. Cassidy ; R. L. Myers-Ward ; D. K. Gaskill ; O. Kazakova
2d Materials (2053-1583). Vol. 3 (2016), 1,
[Artikel, refereegranskad vetenskaplig]

We directly correlate the local (20 nm scale) and global electronic properties of a device containing mono-, bi- and tri-layer epitaxial graphene (EG) domains on 6H-SiC (0001) by simultaneously performing local surface potential measurements using Kelvin probe force microscopy and global transport measurements. Using well-controlled environmental conditions we investigate the doping effects of N-2, O-2, water vapour and NO2 at concentrations representative of the ambient air. We show that presence of O-2, water vapour and NO2 leads to p-doping of all EG domains. However, the thicker layers of EG are significantly less affected. Furthermore, we demonstrate that the general consensus of O-2 and water vapour present in ambient air providing majority of the p-doping to graphene is a common misconception. We experimentally show that even the combined effect of O-2, water vapour, and NO2 at concentrations higher than typically present in the atmosphere does not fully replicate p-doping from ambient air. Thus, for EG gas sensors it is essential to consider naturally occurring environmental effects and properly separate them from those coming from targeted species.

Nyckelord: epitaxial graphene, environmental doping, Hall sensor, Kelvin probe force microscopy, gas sensor



Denna post skapades 2016-05-20. Senast ändrad 2016-07-07.
CPL Pubid: 236773

 

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Projekt

Denna publikation är ett resultat av följande projekt:


Graphene-Based Revolutions in ICT And Beyond (GRAPHENE) (EC/FP7/604391)