Electromodulation spectroscopy of In0.53Ga0.47As/In0.53Ga0.23Al0.24As quantum wells

In0.53Ga0.47As/In0.53Ga0.23Al0.24As quantum wells (QWs) of various widths have been grown by molecular beam epitaxy on the InP substrate and investigated by electromodulation spectroscopy, i.e. photoreflectance (PR) and contactless electroreflectance (CER). The optical transitions related to the QW barrier and the QW ground and excited states have been clearly observed in PR and CER spectra. The experimental QW transition energies have been compared with theoretical predictions based on an effective mass formalism model. A good agreement between experimental data and theoretical calculations has been observed when the conduction band offset for the In0.53Ga0.47As/In0.53Ga0.23Al0.24As interface equals ∼60%. In addition, it has been concluded that the conduction band offset for the In0.53Ga0.23Al0.24As/InP interface is close to zero. The obtained results show that InGa(Al)As alloys are very promising materials in the band gap engineering for structures grown on InP substrate.