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Wyszukujesz frazę "T.T." wg kryterium: Autor


Tytuł:
Optical Properties of Al$\text{}_{x}$Ga$\text{}_{1-x}$As$\text{}_{y}$Sb$\text{}_{1-y}$ Epitaxial Layers
Autorzy:
Świątek, K.
Piskorski, M.
Piotrowski, T. T.
Powiązania:
https://bibliotekanauki.pl/articles/1952715.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.55.Cr
78.66.Fd
Opis:
Photoluminescence spectra of Al$\text{}_{x}$Ga$\text{}_{1-x}$As$\text{}_{y}$Sb$\text{}_{1-y}$ layers (x = 0.2-0.5, y = 0.02-0.03) grown by liquid-phase epitaxy on GaSb substrates were studied in a wide temperature range (14-295 K). The temperature changes of energy and intensity of the layer and substrate emission were measured. Linear part of the temperature-induced energy shift of the Al$\text{}_{0.20}$Ga$\text{}_{0.80}$As$\text{}_{0.02}$Sb$\text{}_{0.98}$ band-to-band emission exhibits a slope of -0.3 meV/K and -0.45 meV/K at temperatures 150 K and 295 K, respectively.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 1100-1102
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transition Rate Dependence on the Non-Zero Initial Momentum in the ADK-Theory
Autorzy:
Ristić, V. M.
Miladinović, T. T.
Radulović, M. M.
Powiązania:
https://bibliotekanauki.pl/articles/2047850.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.80.-t
32.80.Fb
32.80.Rm
Opis:
Tunneling regime, introduced by Keldysh, in the interaction of strong lasers with atoms has been now accepted as the reliable method for describing processes when low frequency lasers are involved. Yet it was always assumed that the ionized electrons are leaving the atom with zero initial momentum. Because we are interested in how non-zero momentum influences the transition probability of tunnel ionization, we obtained the exact expression for the momentum. Here the estimation of the transition probability with nonzero momentum included was conducted. Potassium atoms in the laser field whose intensity varied from 10$\text{}^{13}$ W/cm$\text{}^{2}$ to 10$\text{}^{14}$ W/cm$\text{}^{2}$ were studied. It seems that all energy of laser field is used for tunneling ionization process at the beginning of laser pulse - ionization probability is large. After that, with further action of laser pulse, ionization probability decreases, probably because part of laser pulse energy is used for increasing momentum of ejected electrons, leaving smaller amounts of light quanta available for ionization of remaining electrons. If laser pulse lasts long enough, then the amounts of light quanta available for ionization become larger, resulting in increase in ionization probability, now with greater starting energy of ejected electrons.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 909-914
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Near-Band-Edge Photoluminescence from Very High Quality Hexagonal ZnO Bulk Crystals
Autorzy:
Lieu, N. T. T.
Dat, D. H.
Liem, N. Q.
Powiązania:
https://bibliotekanauki.pl/articles/2035657.pdf
Data publikacji:
2003-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.-y
78.55.-m
78.55.Et
Opis:
The near-band-edge photoluminescence spectra of very high quality hexagonal ZnO single crystals in the temperature range between 9 and 305 K were measured. Based on the energetic positions and the evolutions of well-resolved photoluminescence lines with temperature and with excitation power density we interpret the observed photoluminescence lines as resulting from recombination of the free-exciton, bound-exciton, biexciton, inelastic exciton-exciton collision and electron-hole plasma.
Źródło:
Acta Physica Polonica A; 2003, 103, 1; 67-75
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shallow Ohmic Contact System to n-GaAs
Autorzy:
Kamińska, E.
Piotrowska, A.
Piotrowski, T. T.
Barcz, A.
Guziewicz, M.
Adamczewska, J.
Kwiatkowski, S.
Powiązania:
https://bibliotekanauki.pl/articles/1929764.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Ns
Opis:
Low resistance (Au)GeNi ohmic contacts to n-GaAs with smooth morphology and restricted penetration into the substrate have been fabricated. Rapid thermally nitrided tungsten has been demonstrated to be an effective capping layer during the contact processing.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 804-806
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recombination nearby N-n GaSb/GaInAsSb Staggered Lineup Heterojunction
Autorzy:
Popov, A. A.
Imenkov, A. N.
Kolchanova, N. M.
Yakovlev, Yu. P.
Piotrowski, T. T.
Powiązania:
https://bibliotekanauki.pl/articles/1877143.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Nz
Opis:
The recombination nearby large band-offset staggered lineup N-GaSb/n-GaInAsSb heterojunction was investigated by means of the electroluminescence and carrier lifetime measurements. It was demonstrated that the nature of recombination, tuning rate as well as relation between radiative and non-radiative recombination strongly depend on the N-n band-offset and that its increase improves the carrier localization on the N-n interface.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 559-562
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Materials Technology for GaSb-Based optoelectronic Devices
Autorzy:
Piotrowska, A.
Kamińska, E.
Piotrowski, T. T.
Piskorski, M.
Guziewicz, M.
Papis, E.
Gołaszewska-Malec, K.
Kasjuniuk, S.
Powiązania:
https://bibliotekanauki.pl/articles/1952070.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Ns
81.05.Ea
81.40.-z
Opis:
A study is made of surface preparation, metallization, patterning and dielectric deposition with the aim of developing process technology for GaSb-based photonic devices.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 903-906
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence Spectra of ZnAl$\text{}_{2}$O$\text{}_{4}$:Cr$\text{}^{3+}$ Spinel Nanopowders
Autorzy:
Luc, H. H.
Nguyen, T. K.
Nguyen, V. M.
Suchocki, A.
Kamińska, A.
Le, V. K.
Nguyen, V. H.
Luong, T. T.
Powiązania:
https://bibliotekanauki.pl/articles/2037040.pdf
Data publikacji:
2003-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.-b
72.80.Ga
81.05.Je
81.05.Mh
Opis:
The synthetic ZnAl$\text{}_{2}$O$\text{}_{4}$ spinels doped with Cr$\text{}^{3+}$ ions are prepared from ZnSO$\text{}_{4}$, Al$\text{}_{2}$(SO$\text{}_{4}$)$\text{}_{3}$, and Cr$\text{}_{2}$(SO$\text{}_{4}$)$\text{}_{3}$. The spinel single phase is detected from X-ray diffraction. Luminescence properties of Cr$\text{}^{3+}$ in ZnAl$\text{}_{2}$O$\text{}_{4}$ were studied by low temperature luminescence and decay measurements. Four luminescence lines at 14570, 14520, 14460, and 14330 cm$\text{}^{-1}$ were found to originate from structure distortion and the line at 14175 cm$\text{}^{-1}$ - from chromium pairs. The broad emission band at about 13540 cm$\text{}^{-1}$ is considered to arise from a new Cr$\text{}^{3+}$ center in ZnCr$\text{}_{2}$O$\text{}_{4}$.
Źródło:
Acta Physica Polonica A; 2003, 104, 6; 581-587
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Annihilation Methods by Use of LSO Scintillators
Autorzy:
Hirade, T.
Oka, T.
Powiązania:
https://bibliotekanauki.pl/articles/1339992.pdf
Data publikacji:
2014-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
Opis:
$Lu_2SiO_5$:Ce (LSO) scintillator is one of the scintillators used for positron emission tomography because of its high efficiency of gamma-ray detection. We tried to use LSO for positron annihilation lifetime and age-momentum correlation measurements because the high efficiency is needed to reduce the positron irradiation effect during measurements. The high efficiency with reasonable time resolution was successfully obtained by use of the dynode signals from photomultiplier tubes.
Źródło:
Acta Physica Polonica A; 2014, 125, 3; 825-828
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bose-Hubbard Model in the Rotating Frame of Reference
Autorzy:
Polak, T.
Kopeć, T.
Powiązania:
https://bibliotekanauki.pl/articles/1536643.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.30.Jp
03.75.Lm
03.75.Nt
Opis:
Following a novel experimental arrangement which can rotate a two-dimensional optical lattice at frequencies up to several kilohertz we discuss the ground state of the two-dimensional Bose-Hubbard Hamiltonian, relevant for rotating gaseous Bose-Einstein condensates, by employing U(1) quantum rotor approach and the topologically constrained path integral. Ultracold atoms in such a rotating lattice can be used for the direct quantum simulation of strongly correlated systems under large effective magnetic fields. We derive an effective quantum action for the Bose-Hubbard model, which enables a non-perturbative treatment of the zero-temperature phase transition in the rotating frame. We calculate the ground-state phase diagram, analytically deriving maximum repulsive energy for several rational values of the frustration rotation parameter f = 0, 1/2, 1/3, 1/4, and 1/6 for the square and triangular lattice. Performed calculations revealed strong non-monotonical dependence of the critical ratio of the kinetic energy to the repulsive on-site energy, that separates the global coherent from the insulating state, on topology of the lattice.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 279-282
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neutral Bosonic Condensates in Layered 2D Structures under Artificial Magnetic Field
Autorzy:
Polak, T.
Zaleski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1429105.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
05.30.Jp
03.75.Lm
03.75.Nt
Opis:
We show that the properties of the ideal Bose gas in three-dimensional optical lattice can be closely mimicked by finite two dimensional systems with only ten of layers. The match between critical properties strongly depends on the anisotropy of the hopping amplitudes in and between layers which we fully control. The theory we provided can be directly used in the experiments and results in less challenging requirements of the setups. We also present the phase diagram with its non-monotonic dependence of the ratio of tunneling to on-site repulsion when artificial magnetic field is applied to the system.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1312-1314
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Levels and Electrical Activity of Dislocation Electron States in GaAs
Autorzy:
Wosiński, T.
Figielski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1924306.pdf
Data publikacji:
1993-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.70.-r
71.55.Eq
Opis:
Experimental results are presented confirming that the two energy levels in GaAs: E$\text{}_{c}$ - 0.68 eV and E$\text{}_{v}$ + 0.37 eV, discovered in plastically deformed crystals, belong actually to dislocations. In view of recent identification of the electron state of misfit dislocations at an InGaAs/GaAs interface, a correspondence between these levels and dislocation types has been reinterpreted. The first mentioned leve1 belongs likely to α while the second one to β dislocations of 60° (glide set) type. Such a correspondence is compatible with the observed effect of irradiation on dislocation glide motion in GaAs. It is also argued that these energy levels are involved in the phenomenon of unquenchability of the EL2 defects placed in high-stress regions near dislocations.
Źródło:
Acta Physica Polonica A; 1993, 83, 1; 51-58
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic Anisotropy of NiMn/Ni and NiMn/Cu/Ni Thin Films
Autorzy:
Ogawa, T.
Sato, T.
Powiązania:
https://bibliotekanauki.pl/articles/2013074.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.30.Gw
75.50.Lk
75.70.Ak
Opis:
The magnetic anisotropy of reentrant spin glass NiMn thin film, in the vicinity of the ferromagnetic Ni film, is investigated using NiMn/Ni, Cu/Ni/Cu (t=10 Å and 500 Å)/NiMn and NiMn/Ni/Cu (t=10 ÷ 5000 Å)/Ni films. The unidirectional anisotropy field of NiMn layer in NiMn/Ni film is smaller than that of bulk NiMn. In Cu/Ni/Cu (t=10 Å and 500 Å)/NiMn film, the unidirectional anisotropy field is almost independent of the Cu spacer thickness. These results can be explained in terms of magnetic coupling between the magnetic layers in addition to the film structure of NiMn layer.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 491-494
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Image Depth Profiling AES
Autorzy:
Sekine, T.
Sato, T.
Powiązania:
https://bibliotekanauki.pl/articles/1892328.pdf
Data publikacji:
1992-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.35.Dv
Opis:
Image depth profiling AES incorporating an image processing technique has been developed. This method reconstructs a cross-sectional image from acquired 2-dimensional and/or 3-dimensional data. A binary image produced from a secondary electron image through image processing can be used to cut the area of interest for selected area analysis. In a failure analysis of a relay contact, we found by cross-sectional image observation that Fe and Ni permeate from pin holes in an Au layer covering a Fe-Ni alloy. A VTR head made of a polycrystalline ferrite core covered with a Sendust (Si-Al-Fe alloy) layer at the gap has been analyzed. Depth distributions of Al, 0, and Fe on different grains, and Al and O distributions near grain boundaries have been successfully reassembled from the 3-dimensional data.
Źródło:
Acta Physica Polonica A; 1992, 81, 1; 145-157
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Disorder-Assisted Exciton Transport
Autorzy:
Scholak, T.
Zech, T.
Wellens, T.
Buchleitner, A.
Powiązania:
https://bibliotekanauki.pl/articles/1492761.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.15.hj
05.60.Gg
03.65.Ud
03.65.Yz
Opis:
We discuss the possibly constructive role of disorder for the optimization of exciton transport in the FMO (Fenna-Matthews-Olson) light harvesting complex. Our analysis, which models the FMO as a 3D random graph, demonstrates the existence of a small fraction of optimal, though highly asymmetric, non-periodic conformations, which yield near-to-optimal coherent excitation transport. We argue that, on transient time scales, such quantum interference enhanced transport does always better than stochastic activation.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-089-A-094
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Spectral Functions in the Presence of the Antiferromagnetic Order in the Two-Dimensional Hubbard Model
Autorzy:
Zaleski, T.
Kopeć, T.
Powiązania:
https://bibliotekanauki.pl/articles/1536615.pdf
Data publikacji:
2010-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
71.10.-w
71.10.Pm
Opis:
We use a recently proposed quantum SU(2)×U(1) rotor approach for the Hubbard model to calculate electronic spectral functions in a presence of an antiferromagnetic state for any value of the Coulomb interaction. We isolate the collective variables for charge and spin in the form of the space-time fluctuating U(1) phase field and SU(2) rotating spin quantization axis, respectively. As a result, the fermion Green function in the space-time domain becomes a product of a $CP^1$ propagator resulting from the SU(2) gauge fields, U(1) phase propagator and the pseudo-fermion correlation function. In turn, the spectral lines are obtained by performing the convolution of spin, charge and pseudo-fermion Green's functions. We observe an emergence of a sharp peak in the electron spectral functions within the antiferromagnetic phase, whose spectral weight is equal to the antiferromagnetic order parameter.
Źródło:
Acta Physica Polonica A; 2010, 118, 2; 267-272
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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