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Preservation of Surface Conductivity and Dielectric Loss Tangent in Large‐Scale, Encapsulated Epitaxial Graphene Measured by Noncontact Microwave Cavity Perturbations
Author(s) -
Rigosi Albert F.,
Glavin Nicholas R.,
Liu ChiehI,
Yang Yanfei,
Obrzut Jan,
Hill Heather M.,
Hu Jiuning,
Lee HsinYen,
Hight Walker Angela R.,
Richter Curt A.,
Elmquist Randolph E.,
Newell David B.
Publication year - 2017
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201700452
Subject(s) - materials science , dissipation factor , dielectric , graphene , microwave , conductivity , boron nitride , dielectric loss , surface conductivity , optoelectronics , composite material , nanotechnology , chemistry , quantum mechanics , physics
Regarding the improvement of current quantized Hall resistance (QHR) standards, one promising avenue is the growth of homogeneous monolayer epitaxial graphene (EG). A clean and simple process is used to produce large, precise areas of EG. Properties like the surface conductivity and dielectric loss tangent remain unstable when EG is exposed to air due to doping from molecular adsorption. Experimental results are reported on the extraction of the surface conductivity and dielectric loss tangent from data taken with a noncontact resonance microwave cavity, assembled with an air‐filled, standard R100 rectangular waveguide configuration. By using amorphous boron nitride ( a‐ BN) as an encapsulation layer, stability of EG's electrical properties under ambient laboratory conditions is greatly improved. Moreover, samples are exposed to a variety of environmental and chemical conditions. Both thicknesses of a‐ BN encapsulation are sufficient to preserve surface conductivity and dielectric loss tangent to within 10% of its previously measured value, a result which has essential importance in the mass production of millimeter‐scale graphene devices demonstrating electrical stability.