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

Tunnel-injection structures composed of an In0.53Ga0.47As/In0.53Ga0.23Al0.24As quantum well (QW) and a layer of InAs quantum dashes (QDashes) separated by In0.53Ga0.23Al0.24As barriers of various thicknesses have been investigated by contactless electroreflectance. The observed spectral features have been explained taking into account the optical transitions in a combined system of In0.53Ga0.47As QW and InAs QDash wetting layer. It has been shown that there exist electron and hole states which are localized on both sides of such an asymmetric confinement potential. The latter has allowed concluding that the QDash region in tunnel-injection structures can be easily penetrated by the carriers due to the presence of the wetting layer in the self-assembled structure.

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On the mechanisms of energy transfer between quantum well and quantum dashes

Sęk¹,

Kudrawiec²,

Podemski³

et al. 2012

Journal of Applied Physics

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We investigate energy transfer mechanisms from a quantum well (QW) to quantum dashes (QDashes) separated by a few nanometer thick barrier in InAs/InGaAs/InGaAlAs/InP material system. We show that at sufficiently low temperatures excitons, which are non-resonantly photogenerated in the QW and then transferred to the ground state via phonon relaxation, can be retrieved by QDashes. The excess of the transferred energy, defined by the energy difference between the QW and QDash exciton states, can be dissipated via interaction with LO phonons if the respective energy matching is satisfied. This kind of exciton injection from QW to QDashes is a process insensitive to the energy level structure of the individual exciton components, i.e., electrons and holes. It is shown that within the single particle picture, the electron energy in QDashes is higher by more than 50 meV compared to the corresponding QW energy, which prevents the electron transfer from quantum well to the dashes. We show experimentally that despite this unfavorable energy difference for single carriers whole QW excitons are efficiently transferred to QDashes and recombine there radiatively.

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

Cited by 3 publications

References 31 publications

Optical Modulation Spectroscopy

Optical Modulation Spectroscopy

Contactless electroreflectance of optical transitions in tunnel-injection structures composed of an In0.53Ga0.47As/In0.53Ga0.23Al0.24As quantum well and InAs quantum dashes

On the mechanisms of energy transfer between quantum well and quantum dashes

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