TY  - JOUR
A1  - Rudno-Rudziński, W.
A1  - Syperek, M.
A1  - Andrezejewski, J.
A1  - Maryński, A.
A1  - Misiewicz, J.
A1  - Somers, A.
A1  - Höfling, S.
A1  - Reithmaier, J. P.
A1  - Sęk, G.
T1  - Carrier delocalization in InAs/InGaAlAs/InP quantum-dash-based tunnel injection system for 1.55 μm emission
JF  - AIP Advances
N2  - 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.
KW  - physics
KW  - surface collisions
KW  - electronic coupling
KW  - transition radiation
KW  - time-resolved photoluminescence
KW  - photoluminescence excitation
KW  - modulation spectroscopy
KW  - quantum dots
KW  - quantum wells
KW  - delocalization
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181787
VL  - 7
IS  - 1
ER  - 
TY  - JOUR
A1  - Ryczko, K.
A1  - Misiewicz, J.
A1  - Hofling, S.
A1  - Kamp, M.
A1  - Sęk, G.
T1  - Optimizing the active region of interband cascade lasers for passive mode-locking
JF  - AIP Advances
N2  - 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.
KW  - physics
KW  - electrostatics
KW  - transition radiation
KW  - oscillator strengths
KW  - laser spectroscopy
KW  - optical spectroscopy
KW  - atomic and molecular spectroscopy,
KW  - frequency combs
KW  - quantum wells
KW  - laser physics
Y1  - 2017
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181790
VL  - 7
IS  - 1
ER  -