Mini array of quantum Hall devices based on epitaxial graphene.

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 R_H,2 at a filling factor ν=2 starting from a relatively low magnetic field (between 4 T and 5 T) when the temperature was 1.5 K. The 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=1.5K using a commercial precision resistance bridge with 50 μA 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?R_H,2=2 h/e² was smaller than the relative standard uncertainty of the measurement (<1?10^-7) limited by the used resistance bridge. [ABSTRACT FROM AUTHOR]