Robustness of the quantum Hall effect, sample size versus sample   topology, and quality control management of III-V molecular beam epitaxy
  We measure the IQHE on macroscopic (1.5cm x 1.5cm) "quick 'n' dirty" prepared III-V heterostructure samples with van der Pauw and modified Corbino geometries at 1.3 K. We compare our results with (i) data taken on smaller specimens, among them samples with a standard Hall bar geometry, (ii) results of our numerical analysis taking inhomogenities of the 2DEG into account. Our main finding is a confirmation of the expected robustness of the IQHE which favours the development of wide plateaux for small filling factors and very large sample sizes (here with areas 10,000 times larger than in standard arrangements). 
Ralf D. Tscheuschner, Sascha Hoch, Eva Leschinsky, Cedrik Meier,   Sabine Theis, and Andreas D. Wieck