VietNam 2013 

IXth Rencontres du Vietnam
Quy-Nhon, August 4-10, 2013


 Nanophysics: from fundamentals to applications

(the return)


Tuesday 6
Poster Session

› 21:00 - 23:00 (2h)
Quantum Hall effect in graphene for metrology
Fabien Lafont  1@  , Rebeca Ribeiro  1@  , Félicien Schopfer  1@  , Wilfrid Poirier  1, *@  
1 : Laboratoire National de Métrologie et d'Essais
Laboratoire National de Métrologie et d’Essais
29, avenue Roger Hennequin, 78197 Trappes Cedex, France -  France
* : Corresponding author

The quantum Hall effect (QHE) observed in graphene is promising for an application to metrology. Its robustness is an advantage to develop a resistance standard surpassing the GaAs-based one in operating at B » 2 T, at T > 4 K and with higher measurements currents. This would ease the dissemination of the quantum resistance standard. Besides, graphene can be used for a fundamental test of the QHE universality, useful for the SI redefinition.

Previously we have achieved a 10-7 accuracy in the quantized Hall resistance measurements in mono and bilayer exfoliated graphene deposited on SiO2/Si [1]. This work evidenced limitations of such devices: their small size and charged impurities which lead to low QHE breakdown currents via quasi-elastic inter-Landau level scattering.

 It also confirmed prerequisites for this application: large area graphene with controlled environment to get high charge carrier mobility (»10000cm2V-1s-1) and homogeneous low carrier density (~1011cm-2). We will present promising recent results about the QHE in graphene grown by sublimation of SiC and also by CVD on metals. In the first case the role of SiC substrate is addressed [2] and in the second we have pointed out the role of grain boundaries in the dissipation mechanism.

[1] J. Guignard et al, Phys. Rev. B 85, 165420 (2012)

[2] E. Pallecchi et al., Appl. Phys. Lett. 100, 253109 (2012)

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