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1
Content available remote Temperature of a Single Mn Atom in a CdTe Quantum Dot
100%
Papierska J. , Goryca M. , Wojnar P. , Kossacki P.
Acta Physica Polonica A
|
2009
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tom 116
|
nr 5
899-900
EN
In this work we present a study of the temperature of the single magnetic atom embedded in a semiconductor quantum dot versus excitation power and magnetic field. This temperature is defined by the thermal distribution of spin states of single Mn ion, and results from its interaction with the neighborhood. This temperature was found to be much higher than the temperature of the thermal bath. Its dependence on the excitation power and magnetic field is discussed.
2
Content available remote Photoluminescence Dynamics of CdSe Quantum Dot with Single Mn^{2+} Ion under Modulated Excitation
88%
Pilat M. , Goryca M. , Smoleński T. , Pacuski W. , Kossacki P.
Acta Physica Polonica A
|
2014
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tom 126
|
nr 5
1212-1214
EN
A quantum dot with a single magnetic ion is a perfect model system to investigate spin dynamics of a magnetic ion embedded in semiconductor matrix. In this work we present results of spin dynamics studies of Mn^{2+} ion embedded in CdSe quantum dot, performed under modulated excitation of the dot. In particular, the relaxation time of the Mn^{2+} ion in high magnetic field was determined.
3
Content available remote Numerical Rate Equation Approach to Picosecond Charge State Dynamics in CdTe/ZnTe Quantum Dots
75%
Koperski M. , Kazimierczuk T. , Goryca M. , Wojnar P. , Golnik A. , Kossacki P. , Gaj J.
Acta Physica Polonica A
|
2009
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tom 116
|
nr 5
893-895
EN
The rate equation is used for description of photoluminescence dynamics after pulsed excitation of various states of quantum dots. The picosecond dynamics of averaged charge state of quantum dot is described. We compare our simulations with the experiment and come up with the conclusion that probability of carrier capture weakly depends on quantum dot charge state and that electrons and holes are captured non-synchronously.
4
Content available remote Anisotropic Exchange Interaction between p-Shell Electron and s-Shell Hole in CdTe/ZnTe Quantum Dots
75%
Kazimierczuk T. , Golnik A. , Goryca M. , Wojnar P. , Gaj J. , Kossacki P.
Acta Physica Polonica A
|
2009
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tom 116
|
nr 5
882-884
EN
We study electron-hole exchange interaction in a single CdTe/ZnTe quantum dot by polarization-resolved photoluminescence measurements. We focus on recombination of excitonic states involving p-shell electrons: X^{2-} and XX^-. Recombination lines of X^{2-} and XX^- states exhibit fine structure, which can be consistently explained within a model with four parameters δ_{i}^{αβ} representing strength of iso- and anisotropic parts of interaction between s-hole and s- or p-electron.
5
Content available Long Decays of Excitonic Photoluminescence from CdTe/ZnTe Individual Quantum Dots
75%
Piechal B. , Suffczyński J. , Trajnerowicz A. , Goryca M. , Kossacki P. , Golnik A. , Gaj J.
Acta Physica Polonica A
|
2005
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tom 108
|
nr 5
831-836
EN
We present time-resolved micro-photoluminescence study of self-assembled CdTe/ZnTe quantum dots. In addition to the fast radiative decay of the exciton, we observe long components, being of the order of a few nanoseconds. We observe that long decays are present for neutral exciton lines as well as on the biexciton ones. The temperature dependent measurements reveal the non-monotonic behaviour. We find also that the long decays are not mono-exponential. We conclude that the dark exciton states cannot be treated as the only source of long decays in the luminescence. We propose other possible explanation, which is the slowing of luminescence by carrier trapping in high energy states in quantum dots and barriers.
6
Content available remote Magnetoluminescence of a CdTe Quantum Dot with a Single Manganese Ion in Voigt Configuration
75%
Koperski M. , Goryca M. , Kazimierczuk T. , Kossacki P. , Wojnar P. , Gaj J.
Acta Physica Polonica A
|
2011
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tom 119
|
nr 5
618-620
EN
We present a study of the neutral exciton and negative trion recombination spectra of an individual CdTe quantum dot with a single manganese ion, in magnetic field measured in the Voigt configuration. We describe experimental results and compare with a theoretical model. The quantitative agreement between the model and the experiment allows us to determine separately the electron g-factor.
7
Content available remote Magnetization Dynamics of a (Cd,Mn)Te Quantum Well in Pulsed Magnetic Field
75%
Kobak J. , Goryca M. , Kossacki P. , Golnik A. , Karczewski G. , Wojtowicz T. , Gaj J.
Acta Physica Polonica A
|
2009
|
tom 116
|
nr 5
907-908
EN
In this paper we present studies of magnetization relaxation in a (Cd,Mn)Te quantum well containing 3.2% of Mn, after a pulse of magnetic field. The relaxation was found to be very fast, with dominant component faster than 10 ns. Upon application of static magnetic field the relaxation does not slow down, in contrast with the behavior of very diluted quantum wells or bulk material.
8
Content available remote Influence of Growth Break before Capping on Photoluminescence Dynamics of CdSe/ZnSe Self-Assembled Quantum Dots
75%
Nowak S. , Suffczyński J. , Goryca M. , Kossacki P. , Gaj J. , Lee S. , Furdyna J.
Acta Physica Polonica A
|
2008
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tom 114
|
nr 5
1267-1271
EN
Influence of growth breaks before capping of CdSe self-assembled quantum dot layers on photoluminescence dynamics was examined in three samples. Short (5s) break resulted only in a small blue shift, caused probably by partial strain relaxation and/or Zn interdiffusion. Long (20 min) break induced a strong broadening and red shift of the spectra, combined with a dramatic slow down of the photoluminescence decays. The main result of the long break was identified as introduction of defects (impurities), which generate local electric fields and act as traps of photogenerated carriers.
9
Content available remote Resonant Excitation of CdTe/ZnTe Quantum Dot Pairs as a Tool for Spectroscopic Study of the Excitonic p-States
75%
Bogucki A. , Smoleński T. , Goryca M. , Koperski M. , Wojnar P. , Kossacki P.
Acta Physica Polonica A
|
2013
|
tom 124
|
nr 5
788-790
EN
We propose a new method of obtaining a photoluminescence spectrum of a single quantum dot in a self-assembled system of CdTe/ZnTe quantum dots. The method is based on the resonant excitation of a coupled dots pair. The comparison of the spectra in resonance and out of resonance enables the identification of a well-isolated lines related to the excitonic p-states. The application of the method allows the basic characterisation of a quantum dot, including the measurements of linear anisotropy, the excitation power dependence, and the analysis of the photoluminescence in the magnetic field.
10
Content available remote The Novel Multichannel Single Photon Correlations Technique Applied for the Spin Dynamics Study of a Few Mn^{2+} Ions in a CdTe/ZnTe Quantum Dot
75%
Malinowski F. , Koperski M. , Goryca M. , Smoleński T. , Golnik A. , Kossacki P. , Wojnar P.
Acta Physica Polonica A
|
2013
|
tom 124
|
nr 5
791-794
EN
In this work we demonstrate a novel experimental approach to the study of single photon correlations. The introduction of the multichannel detection setup enables the simultaneous measurement of a large number of correlation functions for photons emitted from different energetic ranges. The advantages of this new approach were exploited in a detailed study of the biexciton-exciton recombination cascade in CdTe/ZnTe quantum dots doped with a few Mn^{2+} ions. The information about the dynamics of the magnetic system in the quantum dot during the lifetime of the exciton was obtained from the analysis of the correlation functions.
11
Content available remote Signatures of p-Shell Electron g-Factor in s-Shell Emission of CdTe/ZnTe Quantum Dots
75%
Kazimierczuk T. , Goryca M. , Wojnar P. , Golnik A. , Nawrocki M. , Kossacki P.
Acta Physica Polonica A
|
2011
|
tom 120
|
nr 5
874-876
EN
We analyze the photoluminescence of excitonic complexes containing p-shell electron in the magnetic field in the Faraday configuration. We demonstrate that despite the p-shell electron is not involved directly in the recombination process, its g-factor influences the emission spectrum. We found that in the case of CdTe/ZnTe quantum dots the p-shell electron is significantly less affected by the magnetic field than s-shell electron in the same dot.
12
Content available remote Influence of Configuration Mixing on Energies and Recombination Dynamics of Excitonic States in CdTe/ZnTe Quantum Dots
63%
Smoleński T. , Kazimierczuk T. , Goryca M. , Kossacki P. , Gaj J. , Wojnar P. , Fronc K. , Korkusiński M. , Hawrylak P.
Acta Physica Polonica A
|
2011
|
tom 119
|
nr 5
615-617
EN
We study experimentally and theoretically excitonic recombination processes in CdTe/ZnTe quantum dots. The single quantum dot photoluminescence spectrum was observed and emission lines from X, X^-, X^+ and 2X excitonic states were identified. Experimental results were analysed in the theoretical model based on the effective mass approximation. Numerical calculations of energy positions and recombination probabilities of X, X^-, X^+ and 2X were performed. Computed results reproduce correctly the order and relative positions of emission lines and ratios of radiative lifetimes.
13
Content available remote Excitation Mechanisms of CdTe/ZnTe Quantum Dots under Non-Resonant and Quasi-Resonant Regime
63%
Kazimierczuk T. , Gaj J. , Golnik A. , Goryca M. , Nawrocki M. , Koperski M. , Smoleński T. , Suffczyński J. , Wojnar P. , Kossacki P.
Acta Physica Polonica A
|
2011
|
tom 119
|
nr 5
588-591
EN
We discuss possible mechanisms of quantum dot population control. A set of experiments, including time-resolved photoluminescence, single photon correlations, excitation correlation, and photoluminescence excitation is used to determine the actual mechanism under non-resonant and quasi-resonant regime.
14
Content available remote Spin-Related Spectroscopy of CdTe-Based Quantum Dots
63%
Gaj J. , Kazimierczuk T. , Goryca M. , Koperski M. , Golnik A. , Kossacki P. , Nawrocki M. , Wojnar P. , Karczewski G.
Acta Physica Polonica A
|
2009
|
tom 116
|
nr 5
795-799
EN
This work contains a selection of our recent experimental results in the field of the spin-related spectroscopy of individual CdTe-based quantum dots. After a short description of the sample growth and experimental methods, optical measurements of the charge state dynamics are presented. Then the influence of in-plane anisotropy of the excitonic states of a quantum dot is discussed, followed by a description of experimental studies of information read-out and writing on quantum dot spin states. In particular, spin memory of a single Mn^{++} ion embedded in a CdTe quantum dot is quantitatively assessed. In an outlook part, perspectives opened by recently developed ZnTe lattice-matched Bragg reflectors are discussed.
15
Content available remote Single-Photon Emission from a Highly Excited CdTe Quantum Dot
63%
Nowak S. , Goryca M. , Kazimierczuk T. , Gaj J. , Golnik A. , Kossacki P. , Wojnar P. , Karczewski G.
Acta Physica Polonica A
|
2008
|
tom 114
|
nr 5
1273-1278
EN
Time-resolved correlation measurements were performed to examine the statistics of photon emission from a single quantum dot at high excitation levels. The range of strong powers was determined by the saturation of intensity of excitonic lines. The significant contribution of pulsed background luminescence forced us to sophisticated analysis of the photoluminescence spectra. For quantum dots grown in the Stranski-Krastanov mode, one-photon emission was found to a good approximation. Fluctuation type quantum dots exhibit a significant level of multiphoton emission.
16
Content available remote Statistical Study of the Inter-Dot Excitation Transfer in CdTe/ZnTe Quantum Dots
63%
Koperski M. , Kazimierczuk T. , Goryca M. , Golnik A. , Gaj J. , Nawrocki M. , Wojnar P. , Kossacki P.
Acta Physica Polonica A
|
2011
|
tom 120
|
nr 5
880-882
EN
In this work we present a statistical study of resonantly excited luminescence of coupled CdTe/ZnTe quantum dots studied by photoluminescence excitation measurements. We investigate the probability of resonance occurrence as a function of resonant energy. We come to the conclusion that the distribution of the inter-dot resonances is uniform, which suggests that the inter-dot excitation transfer is not limited by mean density of states in the emitting quantum dots.
17
Content available remote Properties of Excitons in Quantum Dots with a Weak Confinement
51%
Gołasa K. , Molas M. , Goryca M. , Kazimierczuk T. , Smoleński T. , Koperski M. , Golnik A. , Kossacki P. , Potemski M. , Wasilewski Z. , Babiński A.
Acta Physica Polonica A
|
2013
|
tom 124
|
nr 5
781-784
EN
Statistical properties of neutral excitons, biexcitons and trions confined to natural quantum dots formed in the InAs/GaAs wetting layer are reported. The correlation of the trion binding energy and the biexciton binding energy was found. Magnetospectroscopic measurements of the excitons revealed also the correlation of excitonic effective g^* factor of an exciton with the biexciton binding energy. The qualitative picture of the effect of quantum confinement on the observed correlations is presented.
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