MESOSCOPIC EFFECTS IN MACROSCOPIC STRUCTURE WITH QUASI-2D HOPPING CONDUCTIVITY

In Si:B MOS-structures (N-B approximate to 10(18) cm(-3)) the formatio n of quasi-2D channel of hopping conductivity occurs in the region, wh ere Fermi energy crosses impurity band, shifted by gate voltage V-g. R ising gate voltage above zero (V-g > 0, the case of depletion) results in reproducible fluctuations of transverse voltage V-y between Hall p robes at temperatures 4.2-30 K and magnetic fields B up to lT, in spit e of macroscopic sizes of tile sample (150 x 50 mu m(2)) and potential probes (15 x 5 mu m(2)). Mesoscopic V-y-fluctuations are not affected by magnetic field (in the range of B studied). Besides, a conventiona l Hall voltage exists, so these fluctuations of hopping conductivity a re high enough to observe them at tile background of free carrier cond uctivity.