Optical property of InAsP/InP strained quantum wells grown on InP (111)B and (100) substrates

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Abstract
InAsP/InP strained multiple quantum wells (MQWs) were grown on InP (111)B and (100) substrates by gas-source molecular-beam epitaxy. Specular surfaces were obtained under optimized growth conditions on InP (111)B substrates miscut 1° to the 〈110〉 direction. Photoluminescence, absorption and photoluminescence excitation spectra were taken for InAsP/InP strained MQWs at low temperature. Distinct optical transitions were resolved. Energy-level calculations were carried out for both (111)B and (100) MQWs by taking into account the differences in elastic deformation, strain-induced band-edge shift, valence-band anisotropy, and the piezoelectric effect. The peaks were successfully assigned as different interband excitonic transitions. The best fit of the energy-level calculation to the experimental spectra suggests that the valence-band offset ratios (Qv=ΔEv/ΔEg) for (111)B and (100) InAsP/InP heterostructures are 0.35 and 0.30, respectively. This dependence on the substrate orientation was accounted for in terms of the strain-induced band-edge shift.