Strain compensation for InGaAs-AlAs-AlAsSb coupled double quantum wells by controlling the barrier layer composition

A new strain compensation method for the InGaAs/AlAs/AlAsSb coupled double quantum wells (CDQWs) has been proposed. The proposed structure is composed of In0.53Ga0.47As wells, AlAs central barriers, AlAs diffusion-stopping-layers, and AlAsSb external barriers with a high Sb composition which compensate the lattice mismatch produced by the AlAs layers. In the absorption spectra of the fabricated CDQWs, peaks originating from the intersubband transitions (ISBTs) were observed clearly. Furthermore, the intensity and wavelength of the peaks were varied by varying the doping density of the InGaAs wells and the thickness of the AlAs central barriers. The proposed method provides additional latitude in designing all-optical switches based on ISBTs that use the lattice mismatched systems.