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Wyszukujesz frazę "78.67.Hc" wg kryterium: Temat


Tytuł:
Coupling of Quantum Dots with Quantum Wells in a System Based on (Cd,Zn,Mg)Te
Autorzy:
Połczyńska, K.
Janik, E.
Kossacki, P.
Pacuski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1033157.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Et
78.67.Hc
73.21.La
78.67.-n
Opis:
Coupled low dimensional structures have potential applications in quantum computing and spintronics. Using molecular beam epitaxy we fabricated three kinds of systems of coupled quantum wells and quantum dots with different energy order: wells at higher energy than dots, resonant structures, and dots at higher energy than wells. By analysis of photoluminescence and reflectivity spectra, we conclude that there is a possibility of effective carrier tunneling between structures, which opens possibility of subsequent testing of spin transfer efficiency.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 369-371
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimizing the InGaAs/GaAs quantum dots for 1.3 μm emission
Autorzy:
Maryński, A.
Mrowiński, P.
Ryczko, K.
Podemski, P.
Gawarecki, K.
Musiał, A.
Misiewicz, J.
Quandt, D.
Strittmatter, A.
Rodt, S.
Reitzenstein, S.
Sęk, G.
Powiązania:
https://bibliotekanauki.pl/articles/1055140.pdf
Data publikacji:
2017-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.30.Fs
78.67.-n
78.67.Hc
73.22.-f
Opis:
Hereby we present comprehensive experimental and theoretical study on fundamental optical properties and electronic structure of GaAs-based quantum dots grown using metalorganic chemical vapor deposition technique. The substantial redshift of emission, to the second telecommunication window of 1.3 μm, in comparison to standard InGaAs/GaAs quantum dots is obtained via strain engineering utilizing additional capping layer of In_{0.2}Ga_{0.8}As in this context referred to as strain reducing layer. It ensures lowering of the energy of the ground state transition to more application relevant spectral range. Optical properties of the quantum dot structure has been experimentally characterized by means of photoreflectance spectroscopy and power-dependent photoluminescence revealing 3 transitions originating from hybrid states confined in an asymmetric double quantum well formed of the wetting layer and strain reducing layer, as well as higher states of the quantum dots themselves with the first excited state transition separated by 67 meV from the ground state transition. Origin of the observed transitions was confirmed in theoretical modelling using 1-band single-particle approach for the quantum well part, and excitonic quantum dot spectrum obtained within 8 band k·p formalism followed by configuration interaction calculations, respectively. Additionally, photoluminescence excitation spectroscopy measurements allowed to identify a spectral range for efficient quasi-resonant excitation of the investigated quantum dots into the 2D density of states to be in the range of 835-905 nm.
Źródło:
Acta Physica Polonica A; 2017, 132, 2; 386-390
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Controlling the biexciton-exciton cascade kinetics in a quantum dot via coupling to a microcavity optical mode
Autorzy:
Sęk, G.
Krizhanovskii, D.
Kulakovskii, V.
Reitzenstein, S.
Kamp, M.
Powiązania:
https://bibliotekanauki.pl/articles/1160147.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.35.-y
78.55.-m
42.50.Pq
Opis:
The luminescence of single and two exciton states in a quantum dot embedded in the active layer of a micropillar cavity has been investigated. Temperature tuning has been used to bring the energy states of the quantum dot and the cavity into resonance. Studying the resonance behavior of the exciton and biexciton transitions with cavity mode revealed a similar Purcell effect for both lines. The cavity-induced changes of the respective radiative lifetimes have been shown to allow for controlling the ratio between the single and two exciton occupation and their relative emission rates in a single quantum dot.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-44-A-47
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of dielectric medium anisotropy on the polarization degree of emission from a single quantum dash
Autorzy:
Mrowiński, P.
Tarnowski, K.
Olszewski, J.
Somers, A.
Kamp, M.
Höfling, S.
Reithmaier, J.
Urbańczyk, W.
Misiewicz, J.
Machnikowski, P.
Sęk, G.
Powiązania:
https://bibliotekanauki.pl/articles/1159588.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.35.-y
78.55.-m
Opis:
Excitonic emission from single InAs/InGaAlAs/InP quantum dashes has been investigated in the context of degree of linear polarization by post-growth modification of its surrounding dielectric medium. We present optical spectroscopy measurements on a symmetric squared pedestal structures (mesas), and asymmetric rectangular ones oriented parallel or perpendicular to the main in-plane axis of the dashes [1-10]. Polarization resolved microphotoluminescence shows a significant quantitative modification of the degree of linear polarization value from -20% up to 70%. These results have been confronted with calculations of the coupling between the exciton transition dipole moment and electromagnetic field distributed in the vicinity of a quantum dash inside a processed mesa.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-48-A-52
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Transfer Processes in InAs/GaAs Quantum Dot Bilayer Structure
Autorzy:
Pieczarka, M.
Maryński, A.
Podemski, P.
Misiewicz, J.
Spencer, P.
Murray, R.
Sęk, G.
Powiązania:
https://bibliotekanauki.pl/articles/1185237.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.35.-y
78.55.-m
Opis:
We investigate double layer InAs/GaAs quantum dots grown in the Stransky-Krastanov mode by molecular beam epitaxy. The sample consists of two layers of InAs quantum dots separated by 10 nm thick GaAs layer, where the top quantum dot layer of an improved homogeneity is covered by an InGaAs cap. This configuration has allowed for the extension of the dots' emission to longer wavelengths. We probed the carrier transfer between the states confined in a double quantum well composed of InGaAs cap and the quantum dots wetting layer to the states in the quantum dots by means of photoluminescence excitation and photoreflectance spectroscopies. Efficient emission from quantum dots excited at the double quantum well ground state energy was observed. There is also presented a discussion on the carrier injection efficiency from the capping layer to the quantum dots.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-59-A-61
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical and Structural Properties of Cu Doped ZnS Nanocrystals: Effect of Temperature and Concentration of Capping Agent
Autorzy:
Hasanzadeh, J.
Powiązania:
https://bibliotekanauki.pl/articles/1398921.pdf
Data publikacji:
2016-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.-w
61.46.Hk
78.67.Bf
78.67.Hc
Opis:
We have provided the Cu doped zinc sulfide (ZnS:Cu) nanoparticles using a wet chemical synthesis. In principle, the nanoparticles are provided by mixing the reactants in a double distilled water solvent. We have used the mercaptopropionic acid as the capping agent. We have obtained the physical properties of the nanoparticles using the methods: UV absorption, photoluminescence spectroscopy, and X-ray diffraction analysis. The average size of nanoparticles is obtained in the range 3-6 nm. In addition, the X-ray diffraction pattern of ZnS:Cu nanoparticles reveals a zinc-blende crystal structure at room temperature.
Źródło:
Acta Physica Polonica A; 2016, 129, 6; 1147-1150
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Metalorganic Vapour Phase Epitaxy Growth of A^{III}B^{V} Heterostructures Observed by Reflection Anisotropy Spectroscopy
Autorzy:
Zíková, M.
Hospodková, A.
Pangrác, J.
Vyskočil, J.
Hulicius, E.
Oswald, J.
Komninou, P.
Kioseoglou, J.
Powiązania:
https://bibliotekanauki.pl/articles/1398563.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Gh
81.07.Ta
78.67.Hc
78.55.Cr
Opis:
Reflectance anisotropy spectroscopy is a useful technique used for in situ observation of the metalorganic vapour phase epitaxy growth, because it does not require vacuum in the reaction chamber. With this method we are able to observe the quantum dot growth, the incorporation of indium or antimony atoms in the layer or the monolayer growth of GaAs. We can also estimate the amount of InAs needed for the quantum dot formation, the time necessary for the quantum dot growth or reveal the unintended growth of InAs quantum dots from large dissolved InAs objects.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-75-A-78
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Growth and Characterization of Non-Linear Optical Single Crystal: L-cysteine Hydrochloride Monohydrate
Autorzy:
Azeezaa, V.
Arul Pragasam, A.
Sunitha, T.
Koteeswari, P.
Suresh, S.
Powiązania:
https://bibliotekanauki.pl/articles/1401908.pdf
Data publikacji:
2015-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.10.Dn
78.20.Ci
67.55.Hc
Opis:
Nonlinear optical single crystals of L-cysteine hydrochloride monohydrate (LCB) were grown by slow evaporation technique. Single crystal X-ray diffraction analysis revealed the crystal system and helped to determine lattice parameter values. Powder X-ray diffraction analyses were carried out and the diffraction patterns were indexed. The optical properties of the crystals were determined using UV-visible spectroscopy. Optical constants such as refractive index, extinction coefficient and electric susceptibility were determined from UV-visible spectroscopy. The Fourier transform infrared studies confirmed the various functional groups present in the grown crystal. The mechanical behaviour of the grown crystals was studied using Vicker's microhardness tester. The thermal analysis confirmed that the crystal was stable up to 108.7°C. The dielectric constant and the dielectric loss measurements were carried out for different temperatures and frequencies. Second harmonic generation of LCB crystal was investigated by the Kurtz powder technique.
Źródło:
Acta Physica Polonica A; 2015, 128, 3; 423-430
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
CdSe/ZnCdSe Quantum Dot Heterostructures for Yellow Spectral Range Grown on GaAs Substrates by Molecular Beam Epitaxy
Autorzy:
Gronin, S.
Sorokin, S.
Kazanov, D.
Sedova, I.
Klimko, G.
Evropeytsev, E.
Ivanov, S.
Powiązania:
https://bibliotekanauki.pl/articles/1376051.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Hi
78.55.Et
78.67.Hc
68.65.Fg
Opis:
This paper reports on theoretical calculations and fabrication by molecular beam epitaxy of wide-gap II-VI heterostructures emitting in the "true" yellow range (560-600 nm) at room temperature. The active region of the structures comprises CdSe quantum dot active layer embedded into a strained $Zn_{1-x}Cd_{x}Se$ (x=0.2-0.5) quantum well surrounded by a Zn(S,Se)/ZnSe superlattice. Calculations of the CdSe/(Zn,Cd)Se/Zn(S,Se) quantum dot-quantum well luminescence wavelength performed using the envelope-function approximation predict rather narrow range of the total $Zn_{1-x}Cd_{x}Se$ quantum well thicknesses (d ≈ 2-4 nm) reducing efficiently the emission wavelength, while the variation of x (0.2-0.5) has much stronger effect. The calculations are in a reasonable agreement with the experimental data obtained on a series of test heterostructures. The maximum experimentally achieved emission wavelength at 300 K is as high as 600 nm, while the intense room temperature photoluminescence has been observed up to λ =590 nm only. To keep the structure pseudomorphic to GaAs as a whole the tensile-strained surrounding $ZnS_{0.17}Se_{0.83}$/ZnSe superlattice were introduced to compensate the compressive stress induced by the $Zn_{1-x}Cd_{x}Se$ quantum well. The graded-index waveguide laser heterostructure with a CdSe/$Zn_{0.65}Cd_{0.35}Se$/Zn(S,Se) quantum dot-quantum well active region emitting at λ =576 nm (T=300 K) with the 77 to 300 K intensity ratio of 2.5 has been demonstrated.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1096-1099
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Field Effect on the Excitation Spectrum of a Neutral Exciton in a Single Quantum Dot
Autorzy:
Molas, M.
Nicolet, A.
Piętka, B.
Babiński, A.
Potemski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1375688.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
71.35.-y
78.55.Cr
Opis:
Excitation-energy-dependent magnetospectroscopic measurements of a single GaAlAs/AlAs quantum dot were performed. A significant effect of the excitation energy on the photoluminescence spectra is reported. The photoluminescence excitation spectroscopy has been used to investigate the excitation spectrum of a single electron-hole pair - a neutral exciton in magnetic field up to 14 T. The observed resonances exhibit diamagnetic shift characteristic of an s-shell related emission. In our opinion, the creation of excited complexes involving an excited hole and a ground electron is responsible for the process.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1066-1068
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oscillator Strengths of Quantum Transitions in Spherical Quantum Dot $GaAs$/$Al_{x}Ga_{1-x}As$/$GaAs$/$Al_{x}Ga_{1-x}As$ with On-Center Donor Impurity
Autorzy:
Holovatsky, V.
Bernik, I.
Voitsekhivska, O.
Powiązania:
https://bibliotekanauki.pl/articles/1207322.pdf
Data publikacji:
2014-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.21.La
78.67.Hc
71.55.-i
Opis:
The investigation of the electron and hole energies and probability densities is performed for the cases with and without the donor hydrogenic impurity placed into the centre of quantum dot quantum well structures with different thicknesses of layers. The oscillator strengths of intra- and interband quantum transitions in $GaAs$/$Al_{x}Ga_{1-x}As$ core/shell/well/shell spherical quantum dot with ionized on-center donor impurity are estimated. The oscillator strengths of quantum transitions non-monotonously depend on the width of the layers due to the different location of carriers. The optimal geometrical parameters of the nanostructure are estimated for the possibility of multicolor light emission based on interband quantum transitions.
Źródło:
Acta Physica Polonica A; 2014, 125, 1; 93-97
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence Dynamics of CdSe Quantum Dot with Single $Mn^{2+}$ Ion under Modulated Excitation
Autorzy:
Pilat, M.
Goryca, M.
Smoleński, T.
Pacuski, W.
Kossacki, P.
Powiązania:
https://bibliotekanauki.pl/articles/1377238.pdf
Data publikacji:
2014-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.75.Jn
78.47.jd
78.67.Hc
Opis:
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.
Źródło:
Acta Physica Polonica A; 2014, 126, 5; 1212-1214
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Carrier Dynamics and Dynamic Band-Bending in Type-II ZnTe/ZnSe Quantum Dots
Autorzy:
Syperek, M.
Misiewicz, J.
Chan, C.
Dumcenco, D.
Huang, Y.
Chou, W.
Powiązania:
https://bibliotekanauki.pl/articles/1399095.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
78.55.Et
78.47.J-
Opis:
Carrier dynamics and dynamic band-bending in self-assembled ZnTe/ZnSe quantum dots have been studied by means of time-resolved photoluminescence experiment at low temperatures. The experiment reveals clearly type-II character of the confinement potential in the dot manifested in: (i) long photoluminescence decay time constant of 28-35 ns, and (ii) temporal shift of the quantum dot peak emission towards low energy following the laser pulse excitation. The magnitude of the spectral shift Δ E depends on the dot size and the power density of excitation pulse. For the dots under study and given experimental conditions Δ E ≈ 28 ÷ 42 meV.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 821-823
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Confinement Anisotropy on Excitonic Properties in InAs/InP Quantum Dashes
Autorzy:
Mrowiński, P.
Musiał, A.
Sęk, G.
Misiewicz, J.
Höfling, S.
Somers, A.
Hein, S.
Forchel, A.
Powiązania:
https://bibliotekanauki.pl/articles/1399087.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.-y
71.70.Gm
78.67.Hc
73.21.-b
81.07.Ta
Opis:
The influence of confinement potential anisotropy on emission properties of strongly elongated single InAs/InGaAlAs/InP quantum dashes has been investigated by polarization-resolved microphotoluminescence spectroscopy at around 1.5 μm. There have been determined the exciton fine structure splitting, degree of linear polarization of surface emission and biexciton binding energy. The investigated dashes exhibited usually: the exciton anisotropy splitting larger than 100 μeV, the corresponding biexciton binding energy of about 3 meV, and the degree of linear polarization values in the range from 24% to 55%. Here, we presented a correlation of these parameters for several quantum dashes, which can be attributed either to a change in lateral aspect ratio within the ensemble, or the carrier localization on random fluctuations of the dash confinement potential.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 801-804
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of Elongated $In_{0.3}Ga_{0.7}As//GaAs$ Quantum Dots
Autorzy:
Pieczarka, M.
Musiał, A.
Podemski, P.
Sęk, G.
Misiewicz, J.
Powiązania:
https://bibliotekanauki.pl/articles/1399091.pdf
Data publikacji:
2013-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
73.21.La
73.22.-f
Opis:
In this contribution the electronic structure of large $In_{0.3}Ga_{0.7}As//GaAs$ quantum dots is studied theoretically by means of 8 band k · p modeling. These quantum dots constitute unique physical system due to the low strain limit of the Stranski-Krastanow growth mode resulting in relatively large physical volume and elongation of the quantum dots in [1-10] direction. As a result of these critical growth conditions the electronic structure is expected to be very sensitive to the nanostructure size, shape, and composition of the quantum dot as well as the accompanying wetting layer. Another peculiarity of investigated system is the confining potential which is rather shallow and weakened in comparison to standard quantum dots. It makes them very interesting in view of both fundamental study and potential applications. To reveal physical mechanisms determining the optical properties of the investigated system, the electronic structure, mainly the number of confined states, and the wave function extension as a function of both quantum dot size and geometry have been simulated numerically and the importance of electron-hole Coulomb interactions has been evaluated.
Źródło:
Acta Physica Polonica A; 2013, 124, 5; 809-812
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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