Precision quantization of Hall resistance in transferred graphene
  We show that quantum resistance standards made of transferred graphene reach the uncertainty of semiconductor devices, the current reference system in metrology. A large graphene device (150 \times 30 \mum2), exfoliated and transferred onto GaAs, revealed a quantization with a precision of (-5.1 \pm 6.3) \times 10-9 accompanied by a vanishing longitudinal resistance at current levels exceeding 10 \muA. While such performance had previously only been achieved with epitaxially grown graphene, our experiments demonstrate that transfer steps, inevitable for exfoliated graphene or graphene grown by chemical vapor deposition (CVD), are compatible with the requirements of high quality quantum resistance standards. 
Miros{\l}aw Woszczyna, Miriam Friedemann, Martin G\"otz, Eckart Pesel,   Klaus Pierz, Thomas Weimann, Franz J. Ahlers
cond-mat.mes-hall