MESOSCOPIC EFFECTS IN THE HOPPING CONDUCTIVITY REGION OF MACROSCOPIC QUASI-2-DIMENSIONAL SYSTEMS

Mesoscopic effects are discovered in the conductivity of macroscopic ( 50X 150 mu m) metal-oxide-semiconductor (MOS) structures based on Si l ayers with a high boron content (10(18) cm(-3)) in the classical held- effect configuration. These effects are manifested as the gate voltage is varied in the form of stationary quasiperiodic fluctuations of the transverse voltage between potential probes located on opposite later al faces of the sample. The fluctuations are observed at relatively hi gh temperatures (less than or equal to 30 K) and are associated with r estructuring of the percolation cluster, which determines the quasi-tw o-dimensional hopping conductivity at the intersection of the bulk imp urity band with the Fermi level. (C) 1997 American Institute of Physic s.