@article{SyperekAndrzejewskiRudnoRudzińskietal.2017,
  author    = {Syperek, M. and Andrzejewski, J. and Rudno-Rudziński, W. and Maryński, A. and Sȩk, G. and Misiewicz, J. and Reithmaier, J. P. and Somers, A. and H{\"o}fling, S.},
  title     = {The issue of 0D-like ground state isolation in GaAs- and InP-based coupled quantum dots-quantum well systems},
  series = {Journal of Physics: Conference Series},
  volume    = {906},
  journal   = {Journal of Physics: Conference Series},
  number    = {1},
  issn      = {1742-6588},
  doi       = {10.1088/1742-6596/906/1/012019},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-262876},
  year      = {2017},
  abstract  = {The issue of quantum mechanical coupling between a semiconductor quantum dot and a quantum well is studied in two families of GaAs- and InP- based structures at cryogenic temperatures. It is shown that by tuning the quantum well parameters one can strongly disturb the 0D-character of the coupled system ground state, initially located in a dot. The out-coupling of either an electron or a hole state from the quantum dot confining potential is viewed by a significant elongation of the photoluminescence decay time constant. Band structure calculations show that in the GaAs-based coupled system at its ground state a hole remains isolated in the dot, whereas an electron gets delocalized towards the quantum well. The opposite picture is built for the ground state of a coupled system based on InP.},
  language  = {en}
}
@article{RyczkoMisiewiczHoflingetal.2017,
  author    = {Ryczko, K. and Misiewicz, J. and Hofling, S. and Kamp, M. and Sęk, G.},
  title     = {Optimizing the active region of interband cascade lasers for passive mode-locking},
  series = {AIP Advances},
  volume    = {7},
  journal   = {AIP Advances},
  number    = {1},
  doi       = {10.1063/1.4973937},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181790},
  year      = {2017},
  abstract  = {The work proposes possible designs of active regions for a mode-locked interband cascade laser emitting in the mid infrared. For that purpose we investigated the electronic structure properties of respectively modified GaSb-based type II W-shaped quantum wells, including the effect of external bias in order to simultaneously fulfil the requirements for both the absorber as well as the gain sections of a device. The results show that introducing multiple InAs layers in type II InAs/GaInSb quantum wells or introducing a tensely-strained GaAsSb layer into "W-shaped" type II QWs offers significant difference in optical transitions' oscillator strengths (characteristic lifetimes) of the two oppositely polarized parts of such a laser, being promising for utilization in mode-locked devices.},
  language  = {en}
}
@article{RudnoRudzińskiSyperekAndrezejewskietal.2017,
  author    = {Rudno-Rudziński, W. and Syperek, M. and Andrezejewski, J. and Maryński, A. and Misiewicz, J. and Somers, A. and H{\"o}fling, S. and Reithmaier, J. P. and Sęk, G.},
  title     = {Carrier delocalization in InAs/InGaAlAs/InP quantum-dash-based tunnel injection system for 1.55 μm emission},
  series = {AIP Advances},
  volume    = {7},
  journal   = {AIP Advances},
  number    = {1},
  doi       = {10.1063/1.4975634},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-181787},
  year      = {2017},
  abstract  = {We have investigated optical properties of hybrid two-dimensional-zero-dimensional (2D-0D) tunnel structures containing strongly elongated InAs/InP(001) quantum dots (called quantum dashes), emitting at 1.55 μm. These quantum dashes (QDashes) are separated by a 2.3 nm-width barrier from an InGaAs quantum well (QW), lattice matched to InP. We have tailored quantum-mechanical coupling between the states confined in QDashes and a QW by changing the QW thickness. By combining modulation spectroscopy and photoluminescence excitation, we have determined the energies of all relevant optical transitions in the system and proven the carrier transfer from the QW to the QDashes, which is the fundamental requirement for the tunnel injection scheme. A transformation between 0D and mixed-type 2D-0D character of an electron and a hole confinement in the ground state of the hybrid system have been probed by time-resolved photoluminescence that revealed considerable changes in PL decay time with the QW width changes. The experimental discoveries have been explained by band structure calculations in the framework of the eight-band k·p model showing that they are driven by delocalization of the lowest energy hole state. The hole delocalization process from the 0D QDash confinement is unfavorable for optical devices based on such tunnel injection structures.},
  language  = {en}
}
@article{MotykaDyksikRyczkoetal.2016,
  author    = {Motyka, M. and Dyksik, M. and Ryczko, K. and Weih, R. and Dallner, M. and H{\"o}fling, S. and Kamp, M. and Sęk, G. and Misiewicz, J.},
  title     = {Type-II quantum wells with tensile-strained GaAsSb layers for interband cascade lasers with tailored valence band mixing},
  series = {Applied Physics Letters},
  volume    = {108},
  journal   = {Applied Physics Letters},
  number    = {10},
  doi       = {10.1063/1.4943193},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-189795},
  year      = {2016},
  abstract  = {Optical properties of modified type II W-shaped quantum wells have been investigated with the aim to be utilized in interband cascade lasers. The results show that introducing a tensely strained GaAsSb layer, instead of a commonly used compressively strained GaInSb, allows employing the active transition involving valence band states with a significant admixture of the light holes. Theoretical predictions of multiband k.p theory have been experimentally verified by using photoluminescence and polarization dependent photoreflectance measurements. These results open a pathway for practical realization of mid-infrared lasing devices with uncommon polarization properties including, for instance, polarization-independent midinfrared light emitters.},
  language  = {en}
}