Transport and quantum electron mobility in the modulation Si δ-doped pseudomorphic GaAs/In_(0.2)Ga_(0.8)As/Al_(0.2)Ga_(0.8)As quantum well grown by metalorganic vapor phase epitaxy

摘要

A study of transport and quantum mobility of electrons in two-dimensional electron gas (2DEG) in the modulation Si δ-doped pseudomorphic GaAs/In_(0.2)Ga_(0.8)As/Al_(0.2)Ga_(0.8)As quantum well (QW) grown by metalorganic vapor phase epitaxy is presented. Well-resolved Shubnikov-de Haas oscillations of the magnetoresistivity observed at T=4.2 K suggest that the 2DEG with high electron mobility (μ_(t)≈46000 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 investigated sample was attributed to the effect of actual distribution of ionized centers in the sample.