Tomasz Kazimierczuk

University of Warsaw | UW · Institute of Experimental Physics

Raman scattering excitation (RSE) is an experimental technique in which the spectrum is made up by sweeping the excitation energy when the detection energy is fixed. We study the low-temperature ( T = 5 K) RSE spectra measured on four high quality monolayers (ML) of semiconducting transition metal dichalcogenides (S-TMDs), i.e. MoS 2 , MoSe 2 , WS...

Raman scattering excitation (RSE) is an experimental technique in which the spectrum is made up by sweeping the excitation energy when the detection energy is fixed. We study the low-temperature ($T$=5~K) RSE spectra measured on four high quality monolayers (ML) of semiconducting transition metal dichalcogenides (S-TMDs), $i.e.$ MoS$_2$, MoSe$_2$,...

Employing the original, all-optical method, we quantify the magnetic susceptibility of a two-dimensional electron gas (2DEG) confined in the MoSe$_2$ monolayer in the range of low and moderate carrier densities. The impact of electron-electron interactions on the 2DEG magnetic susceptibility is found to be particularly strong in the limit of, studi...

The dielectric environment of atomically thin monolayer (ML) of semiconducting transition metal dichalcogenides affects both the electronic bandgap and the excitonic binding energy in the ML. We investigate the effect of the environment on the in-plane magnetic field brightening of neutral and charged dark exciton emissions in the WSe 2 ML. The mono...

Two-dimensional layered materials offer the possibility to create artificial vertically stacked structures possessing an additional degree of freedom—theinterlayertwist. We present a comprehensive optical study of artificially stacked bilayers (BLs) MoS2 encapsulated in hexagonal BN with interlayer twist angle ranging from 0∘ to 60∘ using Raman sca...

Two-dimensional layered materials offer the possibility to create artificial vertically stacked structures possessing an additional degree of freedom-the interlayer twist. We present a comprehensive optical study of artificially stacked bilayers (BLs) MoS2 encapsulated in hexagonal BN with interlayer twist angle ranging from 0 to 60 degrees using R...

We investigate the origin of emission lines apparent in the low-temperature photoluminescence spectra of $n$-doped WS$_2$ monolayer embedded in hexagonal BN layers using external magnetic fields and first-principles calculations. Apart from the neutral A exciton line, all observed emission lines are related to the negatively charged excitons. Conse...

We present a detailed study of the time-resolved photoluminescence of narrow-line emission centers in WSe2 monolayers and bilayers. Our experiments reveal noninstantaneous photoluminescence intensity rise after the laser pulse. This shows that the simplest excitation model in which the localized states are directly populated by free excitons is not...

Zeeman effect induced by the magnetic field introduces a splitting between the two valleys at K + and K - points of the Brillouin zone in monolayer semiconducting transition metal dichalcogenides. In consequence, the photoluminescence signal exhibits a field dependent degree of circular polarization. We present a comprehensive study of this effect...

Low temperature and polarization resolved magneto-photoluminescence experiments are used to investigate the properties of dark excitons and dark trions in a monolayer of WS2 encapsulated in hexagonal BN (hBN). We find that this system is an n-type doped semiconductor and that dark trions dominate the emission spectrum. In line with previous studies...

Low temperature and polarization resolved magneto-photoluminescence experiments are used to investigate the properties of dark excitons and dark trions in a monolayer of WS$_2$ encapsulated in hexagonal BN (hBN). We find that this system is an $n$-type doped semiconductor and that dark trions dominate the emission spectrum. In line with previous st...

We report on the magneto-photoluminescence of (Cd,Mn)Te/(Cd,Mg)Te quantum wells excited by photons with varied energy. We observe that laser illumination modifies the carrier density and Coulomb disorder in the quantum wells. Three different regimes are analyzed, corresponding to low hole density with low disorder, low hole density with significant...

Magnetoresistance, ac and dc magnetization, and photoluminescence (PL) experiments have been performed on the p-type Zn0.99Mn0.01Te and Zn0.97Mn0.03Te alloys strongly doped with phosphorus (P). The investigated samples exhibit spin glass behavior with ferromagnetic regions near the freezing temperature Tf=1.9 K and colossal negative magnetoresistan...

We report on a magnetoluminescence study of epitaxially grown single CdTe quantum dots doped with small amounts of copper (of the order of 0.1 at. %) embedded in a ZnTe semiconducting matrix. The survey of tens of quantum dots did not reveal the presence of a dot containing one Cu ion in a +2 oxidation state with a localized spin 1/2. Instead, more...

Monolayers of semiconducting transition metal dichalcogenides are two-dimensional direct-gap systems which host tightly bound excitons with an internal degree of freedom corresponding to the valley of the constituting carriers. Strong spin-orbit interaction and the resulting ordering of the spin-split subbands in the valence and conduction bands ma...

Owing to exchange interaction between the exciton and magnetic ion, a quantum dot embedding a single magnetic ion is a great platform for optical control of individual spin. In particular, a quantum dot provides strong and sharp optical transitions, which give experimental access to spin states of an individual magnetic ion. We show, however, that...

We study the relaxation dynamics of the electron system in graphene flakes under a Landau quantization regime using an approach of time-resolved Raman scattering. The nonresonant character of the experiment allows us to analyze the field dependence of the relaxation rate. Our results clearly evidence a sharp increase in the relaxation rate upon the...

Copper-doped self assembled CdSe/ZnSe quantum dots and (Zn,Cd)Se/ZnSe quantum wells are grown by molecular beam epitaxy. Low temperature luminescence properties of these structures are investigated in detail including circular polarization-resolved magneto-photoluminescence and time-resolved spectroscopy. A significant spectral shift of excitonic e...

Lasing relies on light amplification in the active medium of an optical resonator. There are three lasing regimes in the emission from a quantum well coupled to a semiconductor microcavity. Polariton lasing in the strong light–matter coupling regime arises from the stimulated scattering of exciton-polaritons. Photon lasing in the weak coupling regi...

Owing to exchange interaction between the exciton and magnetic ion, a quantum dot embedding a single magnetic ion is a great platform for optical control of individual spin. In particular, a quantum dot provides strong and sharp optical transitions, which give experimental access to spin states of an individual magnetic ion. We show, however, that...

Monolayers of semiconducting transition metal dichalcogenides are two-dimensional direct-gap systems which host tightly-bound excitons with an internal degree of freedom corresponding to the valley of the constituting carriers. Strong spin-orbit interaction and the resulting ordering of the spin-split subbands in the valence and conduction bands ma...

Nuclear spin coherence and relaxation dynamics of all constituent isotopes of an n-doped CdTe/(Cd,Mg)Te quantum well structure are studied employing optically detected nuclear magnetic resonance. Using time-resolved pump-probe Faraday ellipticity, we generate and detect the coherent spin dynamics of the resident electrons. The photogenerated electr...

We study the relaxation dynamics of the electron system in graphene flakes under Landau quantization regime using a novel approach of time-resolved Raman scattering. The non-resonant character of the experiment allows us to analyze the field dependence of the relaxation rate. Our results clearly evidence sharp increase in the relaxation rate upon t...

Nuclear spin coherence and relaxation dynamics of all constituent isotopes of an n-doped CdTe/(Cd,Mg)Te quantum well structure are studied employing optically detected nuclear magnetic resonance. Using time-resolved pump-probe Faraday ellipticity, we generate and detect the coherent spin dynamics of the resident electrons. The photogenerated electr...

A detailed magneto-photoluminescence study of individual (Cd,Mn)Te/(Cd,Mg)Te core/shell nanowires grown by molecular beam epitaxy is performed. First of all, an enhancement of the Zeeman splitting due to sp-d exchange interaction between band carriers and Mn-spins is evidenced in these structures. Then, it is found that the value of this splitting...

Optical orientation of localized/bound excitons is shown to be effectively enhanced by the application of magnetic fields as low as 20 mT in monolayer WS$_2$. At low temperatures, the evolution of the polarization degree of different emission lines of monolayer WS$_2$ with increasing magnetic fields is analyzed and compared to similar results obtai...

We present a polarization-resolved photoluminescence study of the exchange interaction effects in a prototype system consisting of an individual Fe2+ ion and a single neutral exciton confined in a CdSe/ZnSe quantum dot. Maximal possible number of eight fully linearly-polarized lines in the bright exciton emission spectrum is observed, evidencing co...

We present a polarization-resolved photoluminescence excitation study of the absorption spectrum of a p-shell neutral exciton in a single CdTe/ZnTe quantum dot. We find that the fine structure of the p-shell exciton is completely analogous to the fine structure of the s-shell exciton, including the selection rules and the effects of a magnetic fiel...

We present a comparative study of two self-assembled quantum dot (QD) systems based on II-VI compounds: CdTe/ZnTe and CdSe/ZnSe. Using magneto-optical techniques we investigated a large population of individual QDs. The systematic photoluminescence studies of emission lines related to the recombination of neutral exciton X, biexciton XX, and singly...

Optical studies of a bright exciton provide only limited information about the hole anisotropy in a quantum dot. In this work we present a universal method to study heavy hole anisotropy using a dark exciton in a moderate in-plane magnetic field. By analysis of the linear polarization of the dark exciton photoluminescence we identify both isotropic...

We study the dynamics of optically induced nuclear spin polarization in a fluorine-doped ZnSe epilayer via time-resolved Kerr rotation. The nuclear polarization in the vicinity of a fluorine donor is induced by interaction with coherently precessing electron spins in a magnetic field applied in the Voigt geometry. It is detected by nuclei-induced c...

Single impurities with nonzero spin and multiple ground states offer a degree of freedom that can be utilized to store the quantum information. However, Fe2+ dopant is known for having a single nondegenerate ground state in the bulk host semiconductors and thus is of little use for spintronic applications. Here we show that the well-established pic...

Supplementary Figure 1. Relative position of ions in the crystal lattice. Supplementary Figure 2. Magneto-photoluminescence of a CdSe/ZnSe QD with a single Fe2+ ion. Supplementary Table 1. Symmetry of five multi-electron orbital states of the Fe2+ ion. Supplementary Note 1. Energy levels of Fe2+ ion in the presence of biaxial strain. Supplementary...

Supplementary Figures 1-2, Supplementary Table 1, Supplementary Notes 1-3 and Supplementary References

We study optically induced nuclear spin dynamics in a fluorine-doped ZnSe epilayer. The nuclear spin relaxation time $T_{1}$ of the $^{77}\text{Se}$ isotope under illumination is measured using an all-optical method in a magnetic field range from 10 to 130 mT and a lower limit for the spin relaxation time $T_{1}^{\text{dark}}$ without illumination...

In monolayers of semiconducting transition metal dichalcogenides, the light helicity ($\sigma^+$ or $\sigma^-$) is locked to the valley degree of freedom, leading to the possibility of optical initialization of distinct valley populations. However, an extremely rapid valley pseudospin relaxation (at the time scale of picoseconds) occurring for opti...

We report on properties of an optical microcavity based on (Cd,Zn,Mg)Te layers and embedding (Cd,Zn)Te quantum wells. The key point of the structure design is the lattice matching of the whole structure to MgTe, which eliminates the internal strain and allows one to embed an arbitrary number of unstrained quantum wells in the microcavity. We eviden...

Optically-induced nuclear spin polarization in a fluorine-doped ZnSe epilayer is studied by time-resolved Kerr rotation using resonant excitation of donor-bound excitons. Excitation with helicity-modulated laser pulses results in a transverse nuclear spin polarization, which is detected as a change of the Larmor precession frequency of the donor-bo...

We present a magnetospectroscopic study of a doubly negatively charged exciton X2- in a CdTe quantum dot doped with a single Mn2+ ion. The X2- emission leading to the singlet final state of an excited electron pair is demonstrated to consist of six distinct lines corresponding to different projections of the Mn2+ spin, similarly as for the neutral...

We introduce photon-statistics excitation spectroscopy and exemplarily apply it to a quantum-dot micropillar laser. Both the intensity and the photon number statistics of the emission from the micropillar show a strong dependence on the photon statistics of the light used for excitation of the sample. The results under coherent and pseudothermal ex...

We study the biexciton formation process in a single CdTe/ZnTe quantum dot. Consistently with previous studies, we find subquadratic dependence of the biexciton photoluminescence intensity on the excitation power. We quantitatively explain this dependence in terms of the interplay between two alternative biexciton formation mechanisms, including th...

The recent observation of dipole-allowed $P$-excitons up to principal quantum numbers of $n=25$ in cuprous oxide has given insight into exciton states with unprecedented spectral resolution. While so far the exciton description as a hydrogen-like complex has been sufficient for cubic crystals, we demonstrate here distinct deviations: The breaking o...

The quantum confinement in a typical quantum dot (QD) is determined primarily by the nanosystem’s dimensions and average composition.We demonstrate, however, that excitonic properties of natural QDs formed in the InAs/GaAs wetting layer are governed predominantly by effects of random fluctuations of the lattice composition. It is shown that the bie...

A highly excited atom having an electron that has moved into a level with large principal quantum number is a hydrogen-like object, termed a Rydberg atom. The giant size of Rydberg atoms leads to huge interaction effects. Monitoring these interactions has provided insights into atomic and molecular physics on the single-quantum level. Excitons--the...

We exploit the flexibility offered by an (In,Ga)As/GaAs quantum dot spin ensemble to demonstrate that complex dynamic evolutions can be excited in the ensemble magnetization and accessed by tailored pulsed laser protocols. The modes for spin precession about a magnetic field are adapted to the periodic excitation protocol such that at specific time...

We present a direct observation of a coherent spin precession of an individual Mn$^{2+}$ ion, having both electronic and nuclear spins equal to 5/2, embedded in a CdTe quantum dot and placed in magnetic field. The spin state evolution is probed in a time-resolved pump-probe measurement of absorption of the single dot. The experiment reveals subtle...

One-dimensional polariton condensates (PoCos) in a photonic wire are generated through non-resonant laser excitation, by which also a reservoir of background carriers is created. Interaction with this reservoir may affect the coherence of the PoCo, which is studied here by injecting a condensate locally and monitoring the coherence along the wire....

We report on the method of fabrication of a photonic microstructure that contains a single magnetic ion. Exactly one manganese ion was introduced into a self-assembled CdTe quantum dot, which was located in a ZnTe based micropillar cavity. The multistep fabrication procedure includes molecular beam epitaxy growth, optical characterization, and focu...

Statistical properties of neutral excitons, biexcitons and trions con ned 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...

We present the photoluminescence excitation study of the self-assembled CdTe/ZnTe quantum dots doped with manganese ions. We demonstrate the identification method of spontaneously coupled quantum dots pairs containing single Mn2+ ions. As the result of the coupling, the resonant absorption of the photon in one quantum dot is followed by the exciton...

We present an experimental study of electron-electron exchange interaction in self-assembled CdTe/ZnTe quantum dots based on the photoluminescence measurements. The character and strength of this interaction are obtained by simultaneous observation of various recombination channels of a doubly negatively charged exciton, including previously unreco...

We present a comprehensive experimental and theoretical studies of photoluminescence of single CdMnTe quantum dots with Mn content x ranging from 0.01 to 0.2. We distinguish three stages of the equilibration of the exciton-Mn ion spin system and show that the intermediate stage, in which the exciton spin is relaxed, while the total equilibrium is n...

Complex charge variation processes in low-density, direct-type GaAlAs quantum dots embedded in a type-II GaAs/AlAs bilayer are studied by single-photon correlation measurements. Two groups of excitonic transitions are distinguished in the single quantum dot (QD) photoluminescence spectra, namely due to recombination of neutral and charged multiexci...

We demonstrate evidence for a radiative recombination channel of dark excitons in self-assembled quantum dots. This channel is due to a light hole admixture in the excitonic ground state. Its presence was experimentally confirmed by a direct observation of the dark exciton photoluminescence from a cleaved edge of the sample. The polarization resolv...

We show theoretically and experimentally the existence of a new quantum interference(QI) effect between the electron-hole interactions and the scattering by a single Mn impurity. Theoretical model, including electron-valence hole correlations, the short and long range exchange interaction of Mn ion with the heavy hole and with electron and anisotro...

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...

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...

We present a comprehensive photoluminescence study of the exchange interaction in self-assembled CdTe/ZnTe quantum dots. We exploit the presence of multiple charge states in the photoluminescence spectra of single quantum dots to analyze simultaneously the fine structure of different excitonic transitions, including the recombination of neutral exc...

We report on the formation of optically active CdTe quantum dots in ZnTe nanowires. The CdTe/ZnTe nanostructures have been grown by a gold nanocatalyst assisted molecular beam epitaxy in a vapor-liquid solid growth process. The presence of CdTe insertions in ZnTe nanowire results in the appearance of a strong photoluminescence band in the 2.0 eV–2....

Time-resolved microphotoluminescence study is presented for quantum dots which are formed in the InAs/GaAs wetting layer. These dots are due to fluctuations of In composition in the wetting layer. They show spectrally sharp luminescence lines with a low spatial density. We identify lines related to neutral exciton and biexciton as well as trions. E...

We present a comprehensive photoluminescence study of exchange interaction in self-assembled CdTe/ZnTe quantum dots. We exploit the presence of multiple charge states in the photoluminescence spectra of single quantum dots to analyze simultaneously fine structure of different excitonic transitions, including recombination of neutral exciton/biexcit...

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.

In this paper we present optical studies of CdTe quantum dots formed using Zn-induced reorganization. The pattern of quantum dot photoluminescence lines is found to be similar to typical results reported for quantum dots grown with other techniques, although the positively charged exciton line is relatively more pronounced. Also the energy spacing...

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 d...

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. Numeri...

We study the formation dynamics of a spontaneous ferromagnetic order in single self-assembled Cd1-xMnxTe quantum dots (QDs). By measuring time-resolved photoluminescence, we determine the formation times for QDs with Mn ion contents x varying from 0.01 to 0.2. At low x these times are orders of magnitude longer than exciton spin relaxation times ev...

A promising method to investigate dark exciton transitions in quantum dots is presented. The optical recombination of the dark exciton is allowed when the exciton state is coupled with an individual magnetic impurity (manganese ion). It is shown that the efficient radiative recombination is possible when the exchange interaction with the magnetic i...

In this paper we demonstrate optical writing of information on the spin state of a single Mn ion embedded in a CdTe/ZnTe quantum dot. As a tool for Mn spin orientation we use a spin-conserving transfer of excitation between two coupled quantum dots, one of them containing the Mn ion. Excitons created by circularly polarized light act on the Mn ion...

We study the leakage dynamics of charge stored in an ensemble of CdTe quantum dots embedded in a field-effect structure. Optically excited electrons are stored and read out by a proper time sequence of bias pulses. We monitor the dynamics of electron loss and find that the rate of the leakage is strongly dependent on time, which we attribute to an...

We study probability of coupling between randomly distributed quantum dots (QDs) in self-assembled CdTe/ZnTe hetero-structures grown with different thickness of CdTe formation layer. Photoluminescence excitation spectra reveal a number of QD pairs involved in inter-dot energy transfer. The statistics of dot pairs was collected at numerous spots of...

We present a study of photoluminescence dynamics of CdTe/ZnTe quantum dots using subpicosecond excitation correlation technique. The quantum dot is excited by pairs of light pulses with tuned delay between them. The variation of relative intensity of photoluminescence lines corresponding to different charge states is observed in a timescale of 20 p...

The spin dynamics of a single Mn ion confined in a CdTe/(Cd, Mg, Zn)Te quantum dot is determined by measurements of photon correlation of photoluminescence. The characteristic time of spin flip is a few nanoseconds and strongly depends on the excitation power.

We study coupled asymmetric quantum dot pairs in a single plane self-assembled CdTe/ZnTe system. Inter-dot energy transfer is demonstrated by measurements of photoluminescence excitation spectra. We show exciton spin conservation during the transfer. The spin is preserved if the anisotropy of the quantum dot is suppressed by applied magnetic field...

We present a selection of our studies on CdTe/ZnTe quantum dots considered as spin qubits. Discussed experiments are related to processes of spin reading, writing and evolution. We show that CdTe/ZnTe system is well suitable for studying effects important for optical quantum computing on single spins.

We present a spectroscopic study of excitation dynamics in self-assembled CdTe/ZnTe quantum dots. Insight into details of kinetics is obtained from the time-resolved microphotoluminescence, single photon correlation, and subpicosecond excitation correlation measurements done on single quantum dots. It is shown that the pulsed excitation at an energ...

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 st...

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...

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...

We examine the influence of a weak non-resonant illumination on the quantum dot photoluminescence spectrum. We observe that even very weak illumination affects both intensity and spectral position of emission lines in the spectrum. We discover no significant asymmetry in spatial dependence and infer that the observed effects cannot be attributed to...

We report on an optical study of ZnTe-based microcavity and micropillars. Angle-resolved reflectivity studies confirm a high quality of the investigated structure by setting the lower bound on the quality factor Q ≥ 1000, determined from normal-incidence reflection spectra. In a microphotoluminescence study, micropillar modes are observed at temper...

Two coupled CdTe quantum dots, selected from a self-assembled system, one of them containing a single Mn ion, were studied by continuous wave and modulated photoluminescence, photoluminescence excitation, and photon correlation experiments. Optical writing of information on the spin state of the Mn ion has been demonstrated, using the orientation o...

A degenerate pump--probe technique is used to investigate the non equilibrium carrier dynamics in multi--layer graphene. Two distinctly different dynamics of the carrier relaxation are observed. A fast relaxation ($\sim 50$ fs) of the carriers after the initial effect of phase space filling followed by a slower relaxation ($\sim 4$ ps) due to therm...

The pump-probe technique was used to study the reflectance of CdTe based quantum wells. The energy of a pump beam was scanned across excitonic resonances. The observed dynamics for both the energetic position and oscillator strength of excitonic lines is caused by the changes of the population of charge carriers as well as by the spin dependent int...

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...

Asymmetrical horizontal interdot coupling was demonstrated to exist in a system of a single plane of self-assembled CdTe/ZnTe quantum dots. Photoluminescence excitation (PLE), second order photon correlation and optical orientation were used as main experimental tools. Each individual absorbing dot was identified by a sharp PLE resonance, assigned...

The talk summarizes results of our recent optical studies related to spin states in II-VI and III-V semiconductor quantum dot (QD) systems. First the influence of in-plane anisotropy on the QD excitonic spin states is recalled. Then various ways of circumventing, compensating, or exploiting this influence are discussed. Short lifetime of neutral ex...

Spin dynamics of a single electron and an exciton confined in CdTe/ZnTe quantum dot is investigated by polarization-resolved correlation spectroscopy. Spin memory effects extending over at least a few tens of nanoseconds have been directly observed in magnetic field and described quantitatively in terms of a simple rate equation model. We demonstra...

We present photoluminescence (PL) studies of resonant excitation of self-assembled CdTe/ZnTe quantum dots (QDs) by using resonant excitation. Photoluminescence excitation (PLE) measurements revealed the existence of sharp resonances. They were common for the PL lines related to different charge states of the QD. Prom a combination of PL and PLE res...

We present studies of resonant excitation of self-assembled CdTe/ZnTe quantum dots. Photoluminescence excitation measurements revealed existence of sharp resonances, common for photoluminescence lines attributed to different quantum dot charge states. We conclude from the ensemble of photoluminescence and photoluminescence excitation results that w...