SINGLE-ELECTRON TRANSISTOR AS AN ELECTROMETER ON A 2-DIMENSIONAL ELECTRON-SYSTEM

The magnetic field dependence of the chemical potential of a two-dimen sional electron system (2DES), realized in a GaAs/Al0.33Ga0.67As heter ostructure, is measured by using a metallic single-electron transistor (SET) on top of the 2DES. At low magnetic fields, the Landau level de population with increasing magnetic field is observed. At high magneti c fields, charge fluctuations are detected within the quantum-Hall reg ime. The insulator-like behavior of the 2DES in the quantum-Hall regim e is demonstrated by controlling the SET by a metal-gate electrode und erneath the 2DES. (C) 1998 Elsevier Science B.V. All rights reserved.