Transport Properties of p-Type GaAs-(GaAl)As Heterojunctions in High Magnetic Fields

Abstract

In the last few years p-type inversion layers in GaAs-(GaAl)As heterojunctions have been investigated by various groups. The work was motivated by unusual physical properties, especially by the very high hole mobility at low temperatures. Actually, the interest in p-type inversion layers is not new. The first silicon field effect transistors had p-channels for technological reasons. When it was realized that n-channel MOSFETs were advantageous because of the considerably higher electron mobility, more and more attention was attributed to these devices. Never the less quantum effects in p-type silicon in version layers were investigated in detail in the 70’s because it turned out that they had interesting physical properties. In particular, it is possible to modify the subband structure by the surface electric field. The effective masses are strongly dependent on the orientation of the interface and on the magnitude on the electric field present. It was predicted that due to lacking inversion symmetry the Kramers-degeneracy was lifted at finite wave vectors /l, 2/. However, the calculated splitting turned out to be rather small and was never seen in Shubnikov-de Haas experiments. Only recently the splitting was seen in an optical experiment /3/. The previous work on p-type silicon inversion layers has been reviewed by ANDO, FOWLER and STERN /4/.KeywordsHigh Magnetic FieldHole MobilityHeavy HoleQuantum Hall EffectHall ResistanceThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.