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Tytuł:
Quantum dots for temperature sensing
Autorzy:
Doskaliuk, Natalia
Lukan, Yuliana
Khalavka, Yuriy
Powiązania:
https://bibliotekanauki.pl/articles/35139207.pdf
Data publikacji:
2023
Wydawca:
Radomskie Towarzystwo Naukowe
Tematy:
quantum dots
photoluminescence
thermal sensing
temperature sensitivity
II-VI semiconductors
I-III-VI semiconductors
CdTe
CdS
PbS
AgInS2
CuInS2
kropki kwantowe
fotoluminescencja
detekcja ciepła
wrażliwość termiczna
półprzewodniki II-VI
półprzewodniki I-III-VI
Opis:
Quantum dots are three-dimensional nanoparticles of semiconductors with typical sizes ranging from 2 to 10 nm. Due to the quantum confinement effect the energy gap increase with the size decreasing resulting in size-depended and fine-tunable optical characteristics. Besides this, the energy structure of a quantum dot with a certain size is highly sensitive to environmental conditions. These specific properties open a wide range of applications starting from optical and optoelectronic devices and ending with biosensing and life science. Temperature is one of those parameters influencing strongly on the optical properties of semiconductor nanocrystals, which make them promising materials for temperature sensing, more often using a fluorescent response. Compared to the conventional organic dyes already applied in this field, quantum dots exhibit a set of advantages, such as high quantum yield and photostability, long fluorescence lifetime, higher Stokes shift, and ability to surface functionalization with targeted organic molecules aimed to provide them biocompatibility. In this review, we briefly discuss the properties of II-VI and assumingly less toxic I-III-VI quantum dots, mechanisms of temperature-induced fluorescence response, and the feasibility of their practical application in the field of thermal sensing.
Źródło:
Scientiae Radices; 2023, 2, 2; 93-111
2956-4808
Pojawia się w:
Scientiae Radices
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantum Dots - Theory for Experiments
Autorzy:
Jacak, L.
Krasnyj, J.
Wójs, A.
Powiązania:
https://bibliotekanauki.pl/articles/1967993.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
71.35.Ji
78.20.Ls
Opis:
A simple model based on the effective-mass method and treating a quantum dot as a small irregularity of the periodic crystal field is developed and used for the description of the radiative recombination of an exciton captured in that quasi-zero-dimensional structure. The additional peaks appearing in the photoluminescence spectra at the critical quantum dot size are predicted as a consequence of the metastable excited states occurring in the energy spectrum of a confined exciton. The obtained dependence of the photoluminescence spectrum on the dot size and magnetic field reproduces well the available experimental results.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 633-640
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical simulation of coupled quantum dots
Autorzy:
Machowska-Podsiadło, E.
Mączka, M.
Powiązania:
https://bibliotekanauki.pl/articles/378437.pdf
Data publikacji:
2006
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Technologii Elektronowej
Tematy:
kropki kwantowe
równanie Poissona
równanie Schrodingera
LDA
symulacja numeryczna
quantum dots
Poisson equation
Schrödinger equation
numerical simulation
Opis:
In the work we present self-consistent solutions of Poisson and Schrödinger equations which describe electron states in coupled quantum dots. Results for two neighbouring quantum dots formed in an electrostatic way are discussed. Zero-dimensional electron gas is investigated in the structure proposed by Kastner [1] and presented in our earlier works [2-4]. In the work results of simulations performed in three- and two-dimensional space are shown. We included Hartree potential for modeling Coulomb interactions among electrons in the system. We also considered the exchange and correlation potentials which ensured that each discrete energy level was occupied by only one electron. The exchange and correlation potentials were taken into account with the help of the Local Density Approximation (LDA).
Źródło:
Electron Technology : Internet Journal; 2005-2006, 37/38, 13; 1-4
1897-2381
Pojawia się w:
Electron Technology : Internet Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
RKKY Interaction in Coupled Quantum Dots
Autorzy:
Bak, Z.
Jaroszewicz, R.
Gruhn, W.
Powiązania:
https://bibliotekanauki.pl/articles/1810576.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
47.53.+n
75.30.Ds
75.75.+a
Opis:
Assuming that quantum dots are treated as artificial impurities we consider the Ruderman-Kittel-Kasuya-Yosida interaction between their localized magnetic moments. We prove that due to the quantum confinement the carriers that mediate interactions can exhibit fractional spectral dimension. Basing on this result we discuss magnetic interactions in coupled system of quantum dots and leads.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 342-344
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Properties of InAs Quantum Dots
Autorzy:
Willander, M.
Zhao, Q. X.
Jacob, A. P.
Wang, S. M.
Wei, Y. Q.
Powiązania:
https://bibliotekanauki.pl/articles/2035579.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
78.55.Cr
Opis:
InAs quantum dots grown on GaAs substrate were investigated by optical spectroscopy. We particularly emphasized on the photoluminescence intensity, the stability of the photoluminescence intensity versus temperatures and wavelength of the InAs dot emission at various thermal treatments and different structures. We found that hydrogen can strongly passivate nonradiative centers without causing any structure degradation, and both n- and p-type modulation doping can reduce the decrease in the photoluminescence intensity when the sample temperature increases from the helium temperature to room temperature. The emission wavelength and the efficiency of the InAs quantum dots can also be manipulated by choosing proper materials of cap layer.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 567-576
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spectroscopy of Few-Electron Quantum Dots
Autorzy:
Heitmann, D.
Gudmundsson, V.
Rolf, L.
Schüller, C.
Steinebach, C.
Ulrichs, E.
Powiązania:
https://bibliotekanauki.pl/articles/2011111.pdf
Data publikacji:
1999-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.Rn
73.20.Dx
73.20.Mf
78.30.Fs
Opis:
Advances in submicron technology make it possible to realize man-made low-dimensional electronic systems with quantum confined energy states. Superimposing lateral potential onto two-dimensional electron systems for example in AlGaAs-GaAs systems allows one to prepare quantum wires and dots. We will discuss modulation-doped systems. Then, with typical confinement energies in the meV regime, far-infrared and resonant Raman spectroscopy give direct access to the quantum confined energy levels of the systems. One is now approaching the limit to prepare quantum dots with well defined small numbers of electrons per dot, N = 1, 2, 3... It becomes thus possible to perform a kind of "atomic" spectroscopy in these systems.
Źródło:
Acta Physica Polonica A; 1999, 96, 5; 545-557
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrooptical Properties of Cylindrical Quantum Dots
Autorzy:
Schillak, P.
Czajkowski, G.
Powiązania:
https://bibliotekanauki.pl/articles/1791330.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
78.30.Fs
78.67.Hc
78.67.-n
78.90.+t
Opis:
We show how to compute the optical functions (the complex electrosusceptibility tensor, dielectric tensor, electroreflection spectra) for semiconductor quantum dots exposed to a uniform static electric field in the growth direction, including the excitonic effects. The method uses the microscopic calculation of the quantum dot excitonic wave functions and energy levels, and the macroscopic real density matrix approach to compute the electromagnetic fields and susceptibilities. The electron-hole screened Coulomb potential is adapted and the valence band structure is taken into account in the cylindrical approximation, thus separating light- and heavy-hole motions. In the microscopic calculations, using the effective-mass approximation, we solve the 6-dimensional two-particle Schrödinger equation by transforming it into an infinite set of coupled second order 2-dimensional differential equations with the appropriate boundary conditions. These differential equations are solved numerically giving the eigenfunctions and the energy eigenvalues. Having them, we can compute the quantum dot electrooptical functions. Numerical calculations have been performed for an InGaAs quantum dot with a constant electric field applied in the growth direction. A good agreement with experiment is obtained.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 871-873
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Introduction to the Physics of Quantum Dots
Autorzy:
Kardynal, B.
Powiązania:
https://bibliotekanauki.pl/articles/2027478.pdf
Data publikacji:
2001-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.63.Kv
78.67.Lt
81.07.Ta
Opis:
Quantum dots contain only a few well-defined energy levels for electron and/or holes as a result of the confinement of charge in all three spatial dimensions. Here, we describe both the application of photoluminescence spectroscopy and transport measurements to the characterisation of quantum dots and the novel phenomena that they exhibit. These include the Coulomb blockade, single electron tunnelling and single photon detection. The impact of quantum dots on future electronics and directions for future research, such as in quantum computing and cryptography, are addressed.
Źródło:
Acta Physica Polonica A; 2001, 100, 3; 275-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport and Capacitance Spectroscopy of Quantum Dots
Autorzy:
Adamowski, J.
Bednarek, S.
Szafran, B.
Powiązania:
https://bibliotekanauki.pl/articles/2027454.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
73.63.-b
Opis:
A review of recent theoretical studies on a single-electron tunneling in quantum dots is presented. This effect underlies the transport spectroscopy performed on the vertical gated quantum dots and the capacitance spectroscopy on the self-assembled quantum dots. The conditions of the single-electron tunneling are formulated in terms of electrochemical potentials of the electrons in the leads and in the quantum dot. The electrochemical potentials for the electrons confined in the quantum dots can be calculated by solving the many-electron Schrödinger equation. The results obtained by the Hartree-Fock method are presented. For the vertical gated quantum dot, the realistic confinement potential is obtained from the Poisson equation. The application of the self-consistent procedure to the solution of the Poisson-Schrödinger problem is discussed. The calculated positions of the current peaks at zero bias and boundaries of the Coulomb diamonds for non-zero bias are in good agreement with experiment. The influence of an external magnetic field on the single-electron tunneling is also discussed. The spin-orbital configurations of the electrons confined in the quantum dots change with the magnetic field, which leads to features observed in the current-voltage and capacitance-voltage characteristics.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 145-163
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Two-Electron Quantum Dots in Magnetic Field
Autorzy:
Adamowski, J.
Spisak, B.
Powiązania:
https://bibliotekanauki.pl/articles/1968005.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
Opis:
A theoretical description is given for electronic properties of semiconductor quantum dots in a magnetic field. A two-electron model is applied for electrons in a cylindrical quantum dot with a parabolic confinement potential. The eigenvalue problem is solved by the variational method with the trial wave function proposed in the form of linear combination of S-type and P-type Gaussians. The energy levels of singlet and triplet states with arbitrary radial and magnetic quantum numbers have been calculated as a function of the applied magnetic field. The calculated cyclotron transition energies agree well with those measured for InGaAs/GaAs quantum dots. It is shown that the electron-electron interaction has a small influence on the transition energy.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 695-698
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dark States and Transport through Quantum Dots
Autorzy:
Tooski, S.
Bułka, B.
Powiązania:
https://bibliotekanauki.pl/articles/1428598.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.-w
33.57.+c
73.23.-b
73.63.Kv
Opis:
We consider current through triple and quadruple quantum dot systems in an in-plane electric field and in the sequential tunneling regime. The electric field breaks symmetry of the system and can trap electron in a dark state in which current flow can completely be blocked. Consequently rotating the electric field, one can observe current oscillations and blockades due to dark state.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1231-1233
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Solid-State Cavity Quantum Electrodynamics Using Quantum Dots
Autorzy:
Gérard, J. M.
Gayral, B.
Moreau, E.
Robert, I.
Abram, I.
Powiązania:
https://bibliotekanauki.pl/articles/2027452.pdf
Data publikacji:
2001-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.50.Dv
78.55.Cr
Opis:
We review the recent development of solid-state cavity quantum electrodynamics using single self-assembled InAs quantum dots and three-dimensional semiconductor microcavities. We discuss first prospects for observing a strong coupling regime for single quantum dots. We then demonstrate that the strong Purcell effect observed for single quantum dots in the weak coupling regime allows us to prepare emitted photons in a given state (the same spatial mode, the same polarization). We present finally the first single-mode solid-state source of single photons, based on an isolated quantum dot in a pillar microcavity. This optoelectronic device, the first ever to rely on a cavity quantum electrodynamics effect, exploits both Coulomb interaction between trapped carriers in a single quantum dot and single mode photon funneling by the microcavity.
Źródło:
Acta Physica Polonica A; 2001, 100, 2; 129-143
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Excitonic quasimolecule consisting of two semiconductor quantum dots
Autorzy:
Pokutnyi, S.I.
Salejda, W.
Powiązania:
https://bibliotekanauki.pl/articles/173809.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
spatially separated electron and holes
quantum dots
binding energy
Coulomb and exchange interaction
Opis:
The effect of a significant increase in the binding energy of the singlet ground state of an excitonic quasimolecule consisting of two CdS quantum dots, in comparison with the binding energy of a biexciton in a single crystal of CdS (almost by two orders of magnitude), has been found.
Źródło:
Optica Applicata; 2016, 46, 4; 629-637
0078-5466
1899-7015
Pojawia się w:
Optica Applicata
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Mediated Mn-Mn Interaction in Quantum Dots
Autorzy:
Bak, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1428517.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.-c
75.85.+t
85.75.-d
Opis:
We present a theoretical study of magnetic interaction in quantum dots with magnetic $Mn^{2+}$ in dot impurities. We show that gate voltage applied to the quantum dot shifts the centers of electron clouds. Exact formulae for the perturbed spin density allow us to derive expression for the change of the strength of the sp-d coupling. Estimations show that sp-d exchange integral is very sensitive to the gate voltage variations. Exact formulae for the change of the effective exchange integrals are derived. As the spin coded qubits are elements of the RAM memory, a part of the energy stored in magnetic coupling will be dissipated when information is written or erased. We estimate this energy and find it sufficiently large to destroy quantum coherence during quantum computing. Finally, we discuss the interdot spin coupling and show the effect of gate voltage operations on the spin intra- and interdot Ruderman-Kittel-Kasuya-Yosida coupling.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1219-1221
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charging Effects in Self-Assembled CdTe Quantum Dots
Autorzy:
Kłopotowski, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/1492785.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
32.60.+i
71.35.Pq
71.55.Gs
Opis:
In this review, we summarize our achievements in controlling and understanding the charging effects in single self-assembled CdTe quantum dots. We start with analysis of the single dot emission spectrum. For excitation densities small enough to ensure only s-shell recombination, we find that for all dots (also those reported by other groups) the same transition sequence is observed. Namely, the neutral exciton recombination has the highest energy while charged exciton and biexciton transitions are redshifted. This observation remains in a stark contrast to self-assembled InGaAs dots, where charged complexes may appear also on the high energy side of the neutral exciton. We explain the universality of the transition sequence assuming domination of the Coulomb correlations over direct, single particle interactions. Furthermore, through measurement of the recombination rates, we gain access to electron and hole wave functions and their redistributions upon changing the dot occupancy. We find that the electron wave function is rather stiff, while the hole wave function is rather soft owing to enhanced correlations in the valence band. We then corroborate these conclusions with the Stark spectroscopy, where we analyze energy shifts due to electric field imposed on dots embedded in a field effect or diode structure. Finally, we use these structures to obtain controllable tuning of the charge state. We discuss different approaches to this task and find the best tuning efficiency for a structure with enhanced valence band confinement.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 819-829
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupled Quantum Dots - Spatial Correlations between Interacting Carriers
Autorzy:
Szafran, B.
Powiązania:
https://bibliotekanauki.pl/articles/1811910.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
73.43.-f
71.10.Pm
71.35.-y
Opis:
We review results of our modeling of excitons and excitonic trions confined in vertically stacked InGaAs/GaAs self-assembled quantum dots. Electrons and holes in double quantum dots are much more significantly correlated than in a single dot. For that reason our modeling was based on simple confinement potentials that allow for an exact diagonalization of the resulting two- and three-particle Hamiltonians with a precise account for the relative electron and hole localization along the stack. We studied the optical signatures of the coupling in context of the photoluminescence experiments performed in the external electric field. The calculations predicted prior to the experiment the mechanism of the exciton and negative trion dissociation by electron removal from the dot occupied by the hole. We discuss the competition between the tunnel and the electrostatic interdot couplings. Effects of the non-perfect alignment of the dots as well as stacks containing more than two dots are also discussed.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1013-1039
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Many-Exciton Complexes in Self-Assembled Quantum Dots
Autorzy:
Wójs, A.
Hawrylak, P.
Jacak, L.
Powiązania:
https://bibliotekanauki.pl/articles/1952721.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
71.45.Gm
78.66.Fd
Opis:
The system of interacting electrons and holes confined in a lens-shaped InGaAs self-assembled dot is studied using exact diagonalization techniques. The single-particle energy spectrum of self-assembled dot is well approximated by that of a quasi-two-dimensional atom with parabolic lateral confinement. The electronic shell structure of self-assembled dot is responsible for a remarkable dependence of the absorption/emission spectrum on the number of excitons. This is explained in terms of hidden symmetries leading to a formation of coherent many-exciton states of weakly interacting excitons and bi-excitons.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 1108-1112
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quantized Absorption Strength of Multi-Exciton Quantum Dots
Autorzy:
Wójcik, K.
Grodecka, A.
Wójs, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047045.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
78.67.Hc
71.35.-y
Opis:
Energy and absorption/recombination spectra of up to two electron-hole pairs confined in a spherical quantum dot are studied numerically as a function of dot radius (i.e., confinement volume). The transition between fermionic and bosonic behavior of the confined excitons is identified in coincidence with enhancement of low-energy absorption strength.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 423-428
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonance Spectra of Quantum Dots in Magnetic Field
Autorzy:
Bylicki, M.
Jaskólski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1969032.pdf
Data publikacji:
1998-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
73.61.-r
85.30.Vw
73.23.Hk
Opis:
Influence of magnetic field on the energy positions and widths of one electron resonance states in a multi-shell spherical quantum dot is investigated. The one-band effective mass approximation is assumed. The complexeigenvalue Schrodinger equation approach involving complex rotation of coordinates is used to obtain complex eigenenergies, E$\text{}_{r}$ - iΓ/2, corresponding to resonance states. We show how the magnetic field changes the resonance energy, E$\text{}_{r}$, and decay rate, Γ, yielding bound states for some particular cases.
Źródło:
Acta Physica Polonica A; 1998, 94, 2; 271-276
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hole Traps in ZnTe with CdTe Quantum Dots
Autorzy:
Zielony, E.
Płaczek-Popko, E.
Gumienny, Z.
Trzmiel, J.
Karczewski, G.
Guziewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/1791335.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.61.Ga
73.21.La
73.20.Hb
Opis:
In this study the capacitance-voltage (C-V) and deep level transient spectroscopy measurements have been performed on ZnTe (p-type)-Ti/Al Schottky diodes containing a layer of CdTe self-assembled quantum dots and on the reference diodes without dots for comparison. Both kinds of investigated samples were grown by molecular beam epitaxy technique. The dots were formed during the Stransky-Krastanov growth mode. Comparison of the C-V and deep level transient spectroscopy results obtained for both samples allows us to conclude that the 0.26 eV trap observed exclusively for the QD sample can be assigned to some defects in a wetting layer or CdTe/ZnTe interface.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 885-887
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coherent Transport through Systems of Coupled Quantum Dots
Autorzy:
Trocha, P.
Barnaś, J.
Powiązania:
https://bibliotekanauki.pl/articles/2047730.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.23.-b
73.21.La
73.23.Hk
Opis:
Spin-dependent electronic transport through two coupled single-level quantum dots attached to ferromagnetic leads with parallel and antiparallel magnetizations is analyzed theoretically. The intra-dot Coulomb correlation is taken into account, while the inter-dot Coulomb repulsion is omitted. Conductance and tunnel magnetoresistance associated with magnetization rotation are calculated by the nonequilibrium Green function technique. The relevant Green functions are derived by the equation of motion method in the Hartree-Fock approximation. The dot occupation numbers and the Green functions are calculated self-consistently. The interference effects in electronic transport through quantum dots are analyzed in two different configurations. It is shown that the Fano resonance in conductance can be observed even for vanishing inter-dot hopping parameter t. The interplay of the interference effects and the Coulomb interactions in quantum dots is also analyzed.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 473-480
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Spin-Related Spectroscopy of CdTe-Based Quantum Dots
Autorzy:
Gaj, J.
Kazimierczuk, T.
Goryca, M.
Koperski, M.
Golnik, A.
Kossacki, P.
Nawrocki, M.
Wojnar, P.
Karczewski, G.
Powiązania:
https://bibliotekanauki.pl/articles/1585136.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.70.Gm
75.75.+a
78.55.Et
Opis:
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.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 795-799
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deep Levels Induced by CdTe/ZnTe Quantum Dots
Autorzy:
Zielony, E.
Placzek-Popko, E.
Roznicka, A.
Gumienny, Z.
Szatkowski, J.
Dyba, P.
Pacuski, W.
Kruse, C.
Hommel, D.
Guziewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2048061.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.61.Ga
73.21.La
73.20.Hb
Opis:
The electrical properties of the CdTe/ZnTe quantum dot system have been analyzed to identify deep-level defects related with the presence of quantum dots. The capacitance-voltage (C-V) and deep level transient spectroscopy measurements were used to investigate the samples. A reference ZnTe sample (without dots) was also studied for comparison. Both samples were grown by molecular beam epitaxy technique on the n-type GaAs substrate. The quantum dots were formed by a Zn-induced reorganization of a thin CdTe layer. The presence of quantum dot formation was confirmed by micro-photoluminescence measurements. The deep level transient spectra for both samples are complex. In order to characterize individual contributions to the deep level transient spectra the latter have been simulated by separated Gaussian components [1]. The results of the deep level transient spectroscopy measurements yield the conclusion that the same defects are present in both materials but there is an increased concentration of the defects in the quantum dot structures. No deep level associated directly with the quantum dot confinement has been identified.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 630-632
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Self-Assembled CdTe/ZnTe Quantum Dots
Autorzy:
Kowalik, K.
Kudelski, A.
Golnik, A.
Gaj, J. A.
Karczewski, G.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/2035754.pdf
Data publikacji:
2003-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.70.Ej
Opis:
We present microluminescence investigations of self-assembled CdTe/ZnTe quantum dots. The dots proprieties resulting from our studies are: values of optical in-plane anisotropy parameters (electron - heavy hole exchange splitting and orientation of anisotropy) and value of effective Lande factor. Parameters giving information about in-plane anisotropy possess random distribution of values with the exchange splitting from 0 to 240 μeV. The effective Lande factor values for our dots are around g$\text{}^{*}$=-3.2 with a scatter of about 18%. Some PL lines exhibit sudden jumps of energetic position, related to variation of the charge state in their neighborhood.
Źródło:
Acta Physica Polonica A; 2003, 103, 6; 539-544
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Intershell Exchange Interaction in Charged GaAlAs Quantum Dots
Autorzy:
Molas, M.
Nicolet, A.
Potemski, M.
Babiński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399082.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.35.-y
78.55.Cr
71.70.Gm
Opis:
Optical anisotropy of charged excitons and biexcitons related to the single-particle s- and p-shell emission in GaAlAs/AlAs quantum dots is investigated. The polarization-dependence and time-resolved micro-photoluminescence measurements were performed. Cross-correlation measurements were used to identify the ladder of excitonic states and allowed us to show two cascade pathways, including the spin singlet and triplet states of charged excitons and biexcitons. The fine structure of the studied states is described and analysed in terms of electron-electron, hole-hole, and electron-hole exchange interactions.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 785-787
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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