PROPERTIES OF A HIGH-MOBILITY 2-DIMENSIONAL ELECTRON-GAS IN MODULATION-DOPED QUANTUM-WELL STRUCTURES OF GAINAS ALINAS AND GAINAS/(GA1-XALX)INAS HETEROSTRUCTURES/

The electronic and magnetotransport properties of the two-dimensional electron gas (2DEG) in MBE-grown GaInAs/AlInAs and GaInAs/(Ga1-xAlx)In As heterostructures are investigated in magnetic fields up to 12 T. Th e quantum oscillations of the magnetoresistivity (SdH effect) and the observation of pronounced quantum Hall effect demonstrate the existenc e of a high-mobility 2DEG in the GaInAs potential well. The characteri stic parameters of the electronic band structure of the 2DEG are deter mined and are compared with self-consistent solutions of the coupled P oisson and Schrodinger equations. The influence of hydrostatic pressur e on the magnetotransport properties is studied. A surprisingly weak c hange of the subband occupation with pressure is revealed.