Influence of Ionized Impurities on the Transport Properties of a Two-DimensionalElectron Gas

摘要

Experiments on 2-Dimensional Electron Gases (2DEG) in GaAs/Al(x)Ga(1-x)Asheterostructures and Si delta doped GaAs structures are studied. Focus is on the influence of ionized impurities on the transport properties of a 2DEG. In the first heterostructures the changing of the interaction between the electrons and the charged impurities by illumination and by the application of a backgate voltage are studied. In the GaAs structures the influence of the charged impurities on the electrons in the various populated sub-bands are studied. The influence of the ionized donors on the integer and fractional Quantum Hall Effect (QHE) are studied. The integer and fractional QHE are shown to have a different physical origin.