Two-dimensional electron gas systems at semiconductor interfaces.

The heterointerface between epitaxial layers of dissimilar semiconductors forms a useful locus for confinement of electrons to two-dimensional motion. Electrons with high mobilities and long scattering times may be introduced by modulation doping and display strong magneto quantum effects including quantum Hall effect and fractional quantization of the Hall effect indicative of new ordered states of the two-dimensional electrons. Holes may be confined and introduced by similar techniques and also exhibit enhanced lifetimes and integral and fractional Hall effect quantization.