Series connection of four quantum Hall effect (QHE) devices based on epitaxial graphene films was studied for realization of a quantum resistance standard with an up-scaled value. The tested devices showed quantum Hall plateaux RH,2 at filling factor i = 2 starting from relatively low magnetic field (between 4 T and 5 T) when temperature was 1.5 K. Precision measurements of quantized Hall resistance of four QHE devices connected by triple series connections and external bonding wires were done at B = 7 T and T = 1.5 K using a commercial precision resistance bridge with 50 microA current through the QHE device. The results showed that the deviation of the quantized Hall resistance of the series connection of four graphene-based QHE devices from the expected value of 4*RH,2 = 2h/e^2 was smaller than the relative standard uncertainty of the measurement (< 1*10^-7) limited by the used resistance bridge.
@article{arxiv.1512.03163,
title = {Mini array of quantum Hall devices based on epitaxial graphene},
author = {S. Novikov and N. Lebedeva and J. Hamalainen and I. Iisakka and P. Immonen and A. J. Manninen and A. Satrapinski},
journal= {arXiv preprint arXiv:1512.03163},
year = {2016}
}