Transport and quantum electron mobility in the modulation Si delta-doped pseudomorphic GaAs/In0.2Ga0.8As/Al0.2Ga0.8As quantum well grown by metalorganic vapor phase epitaxy

A study of transport and quantum mobility of electrons in two-dimensional e lectron gas (2DEG) in the modulation Si delta-doped pseudomorphic GaAs/In0. 2Ga0.8As/Al0.2Ga0.8As quantum well (QW) grown by metalorganic vapor phase e pitaxy is presented. Well-resolved Shubnikov-de Haas oscillations of the ma gnetoresistivity observed at T = 4.2 K suggest that the 2DEG with high elec tron mobility (mu(t) approximate to 46 000 cm(2)/V s) formed in the QW with no significant parallel conduction. A persistent photoconductivity effect resulted in an increase in electron sheet density. An increase of transport and quantum mobilities up to the onset of the second subband occupancy was observed. Further illumination resulted in a decrease of both mobilities. Strong dependence of the quantum mobility on the thermal history of the inv estigated sample was attributed to the effect of actual distribution of ion ized centers in the sample. (C) 2000 American Institute of Physics. [S0003- 6951(00)02833-3].