Illumination as a tool to investigate the quantum mobility of the two-dimensional electron gas in a Si δ-dopedGaAs/In0.15

Abstract

A series of GaAs/InGaAs quantum wells with a silicon δ-doped layer in the top barrier was investigated by Shubnikov-de Haas measurements as a function of the illumination time of the samples. During the illumination process strong modifications of the electronic density and the quantum mobility of each occupied subband were observed. Based on self-consistent calculations, the dominant mechanism which caused the changes in the subband quantum mobilities with illumination was elucidated.

Magnetotransport study on the defect levels of delta-doped In0.22Ga0.78As∕GaAs quantum wells

“…For instance, one can select appropriate alloy compositions and barrier materials for QWs to match the lattice constant of the substrate, e.g., In 0.52 Al 0.48 As/ In 0.53 Ga 0.47 As QW grown on InP substrate, 1,2 or choose the more mature GaAs as a substrate to grow a strain-layered QW, e.g., In x Ga 1−x As/ GaAs QW. [3][4][5][6] Because the lattice constant of InAs ͑6.0583 Å͒ is much greater than that of GaAs ͑5.653 25 Å͒, a strain is built in the In x Ga 1−x As/ GaAs system when the lattice-mismatched QW is grown. To attain the optimum strain properties in the lattice-mismatched QW, one has to overcome two obstacles: ͑i͒ keeping the layer thickness under the critical strainedlayer condition and ͑ii͒ reducing the defects caused by the lattice mismatch.…”