QUANTUM TRANSPORT EFFECTS IN A 2-DIMENSIONAL ELECTRON-GAS AS A TOOL FOR THE INVESTIGATION OF HETEROINTERFACES

We have studied the influence of interface defects on low temperature galvanomagnetic effects in a two-dimensional electron gas (2DEG). Experiments have shown a non-ideal character of the InP/In0.53Ga0.47As interface in modulation-doped structures with 2DEG grown by liquid phase epitaxy. That is why such structures have been chosen for investigation. The following galvanomagnetic effects were investigated at liquid helium temperatures: the Hall mobility; the oscillatory magnetoresistance in a magnetic field perpendicular to the heterointerface; the negative magnetoresistance in a weak magnetic field parallel to 2DEG. The quantitative analysis of these effects allowed one to determine the interface parameters: the amplitude delta = 7-10 Angstrom and the lateral size Lambda = 50-70 Angstrom of small-scale interface fluctuation, the interface charge density N-z = (8 +/- 2) X 10(9) cm(-2) and the amplitude of large-scale 2DEG density fluctuations delta n(s)/n(s) approximate to 5%.