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 (1.5 cm x 1.5 cm) ''quick and dirty '' prepared III-V heterostucture samples with van der Pauw and modifie d Corbino geometries at 1.3 K. We compare our results with (i) data ta ken 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 e xpected robustness of the IQHE which favors the development of wide pl ateaux for small filling factors and very large samples sizes (here wi th areas 10 000 times larger than in standard arrangements).