The effects of interdiffusion on the polarization insensitivity in a tensile-strained barrier GaAs/GaAsP quantum well

The tensile-strained barrier GaAs/GaAsP quantum-well (QW) structure fabricated on GaAs substrate has been used in achieving merged LH and HH valence subbands in order to obtain optical polarization insensitive photonics devices. In this structure, the GaAs QW layer is embedded in tensile-strained GaAsP barriers grown on GaAs substrates. In the case of tensile-strained barrier GaAs/GaAsP QW, a small amount of light-hole (LH) and heavy-hole (HH) splitting is attainable within a large range of well width and P compositions. Through quantum well intermixing, it is possible to cause the coincidence of energy levels of HH and LH resulting in polarization-insensitive device operation. In this paper, the valence HH–LH splitting properties of intermixed GaAs QW with tensile-strained GaAsP barriers are reported.