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Tytuł:
Time-Resolved and Near-Field Scanning Optical Microscopy Study on Porphyrin J-Aggregate
Autorzy:
Miura, A.
Matsumura, K.
Su, X.
Tamai, N.
Powiązania:
https://bibliotekanauki.pl/articles/1993153.pdf
Data publikacji:
1998-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
Opis:
Water-soluble porphyrin, 5,10,15,20-tetraphenyl- 21H,23H-porphine-tetrasulfonic acid (TPPS), forms J-aggregate in aqueous solution depending on experimental conditions such as pH, dye concentration, and/or ionic strength. The steady-state fluorescence and picosecond single-photon timing spectroscopy were applied for protonated monomer and J-aggregate in aqueous solution and in thin films to reveal the dynamics in the S$\text{}_{2}$ and S$\text{}_{1}$ states. The S$\text{}_{2}$ fluorescence spectra from the protonated monomer and J-aggregate were observed in addition to the normal S$\text{}_{1}$ fluorescence. The lifetime of the S$\text{}_{2}$ state was estimated to be ≈5 ps for J-aggregate, whereas the lifetime is shorter than 1 ps for protonated TPPS monomer. The mesoscopic structures of J-aggregate in thin film with and without polymer on the glass surface were examined by scanning near-field optical microscopy. With the surface topography and scanning near-field optical microscopy transmission images, TPPS J-aggregate was found to form a long and narrow tube-like structure which has a few μm length, 0.2-0.5 μm width, and 5-30 nm height. An unidirectional orientation of the structure was also found, which may be originated from the spin-coating process.
Źródło:
Acta Physica Polonica A; 1998, 94, 5-6; 835-846
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrafast Optical and Magneto-Optical Dynamics in Colossal-Magnetoresistance Manganites
Autorzy:
Dorosinets, V.
Richter, P.
Jakob, G.
Roskos, H. G.
Powiązania:
https://bibliotekanauki.pl/articles/2041730.pdf
Data publikacji:
2005-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
Opis:
Transient pump-probe reflectance measurements on La$\text{}_{0.67}$Ca$\text{}_{0.33}$MnO$\text{}_{3}$/MgO and La$\text{}_{0.67}$ Ca$\text{}_{0.33}$MnO$\text{}_{3}$/SrTiO$\text{}_{3}$ thin films reveal a hitherto unknown magnetization-dependent energy gap that determines the relaxation process of the optically excited charge carriers on the picosecond time scale. In the case of La$\text{}_{0.67}$Ca$\text{}_{0.33}$MnO$\text{}_{3}$/SrTiO$\text{}_{3}$, the subsequent reflectance dynamics at low temperatures is determined to be substrate-induced strain that drives the sample into a metastable state characterized by an increased number of paramagnetic domains.
Źródło:
Acta Physica Polonica A; 2005, 107, 1; 211-214
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Four-Wave Mixing Spectroscopy of Quantum Dot Molecules
Autorzy:
Sitek, A.
Machnikowski, P.
Powiązania:
https://bibliotekanauki.pl/articles/2047371.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
78.47.+p
Opis:
We study theoretically the nonlinear four-wave mixing response of an ensemble of coupled pairs of quantum dots (quantum dot molecules). We discuss the shape of the echo signal depending on the parameters of the ensemble: the statistics of transition energies and the degree of size correlations between the dots forming the molecules.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 167-172
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hot Photoluminescence in CdTe/CdMnTe Quantum Well Structures Grown by Molecular Beam Epitaxy
Autorzy:
Godlewski, M.
Wojtowicz, T.
Karczewski, G.
Kossut, J.
Bergman, J. P.
Holtz, P. O.
Monemar, B.
Powiązania:
https://bibliotekanauki.pl/articles/1968096.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
78.55.Et
Opis:
A step-like emission is observed for CdTe/CdMnTe structures δ-doped with In. The new photoluminescence cannot be explained by neither the Raman process nor by the "ordinary" hot photoluminescence. We propose that magnetic interactions are responsible for the new photoluminescence appearing due to a dramatic increase in a thermalization time of hot excitons.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 765-768
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Theory of Optically Nonlinear Effects in Ultrafast Spatio-Temporal Dynamics of Semiconductors
Autorzy:
Knorr, A.
Steininger, F.
Koch, S. W.
Powiązania:
https://bibliotekanauki.pl/articles/1967994.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
78.66.-w
Opis:
Ultrafast spatio-temporal effects in optically excited semiconductors are investigated by solving the coupled semiconductor Maxwell-Bloch equations which include the relevant relaxation phenomena. The analysis is used to describe transport of electronic excitations on nano- to micrometer scales with a dynamic range on the femto- to picosecond time scale.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 641-651
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Recombination Processes in Doped CdTe/CdMnTe Multiple Quantum Well Structures Grown by Molecular Beam Epitaxy
Autorzy:
Godlewski, M.
Wojtowicz, T.
Karczewski, G.
Kossut, J.
Bergman, J. P.
Monemar, B.
Powiązania:
https://bibliotekanauki.pl/articles/1968089.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
78.55.Et
Opis:
An influence of doping level on exciton properties in n-doped multiple quantum well structures of CdTe/CdMnTe is studied for multiple quantum well structures prepared in the way that donor (indium) concentration changes within the length of the sample. We show that the formation scenario for neutral donor bound excitons in low-dimensional structures can be different from that observed in bulk samples. We further show that in the case of such quantum well structures we can selectively excite either photoluminescence emission of localized or donor bound excitons, which is a consequence of surprisingly weak energy transfer link between two types of excitonic transitions.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 757-760
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exciton Transfer in Multiple Quantum Well Structures of CdTe/CdMnTe Grown by Molecular Beam Epitaxy
Autorzy:
Godlewski, M.
Surma, M.
Wilamowski, Z.
Wojtowicz, T.
Karczewski, G.
Kossut, J.
Holtz, P. O.
Bergman, J. P.
Monemar, B.
Powiązania:
https://bibliotekanauki.pl/articles/1968091.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
78.55.Et
Opis:
The direct evidence for the efficient transfer of excitons from 4 nm and 6 nm to 10 nm wide CdTe quantum wells is presented based on the results of photoluminescence and photoluminescence excitation investigation. Efficient transfer is observed for quantum wells separated by thick (50 nm) CdMnTe barriers containing 10% or 30% Mn fraction. A new mechanism of the transfer is proposed, which involves long range dynamic magnetic interactions between free/bound excitons and Mn ions in the CdMnTe barrier regions of the structure.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 761-764
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optically-Determined Exciton Transport in GaAs Structures
Autorzy:
Gililand, G. D.
Wolford, D. J
Hjalmarson, H. P
Petrovic, M. S.
Klem, J.
Kuech, T. F.
Northrop, G. A.
Bradley, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/1929606.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
72.80.Ey
Opis:
We have used an all-optical photoluminescence-imaging technique to measure excitonic transport in three types of GaAs structures in which the excitonic transitions vary from allowed direct-gap excitons to forbidden, doubly-indirect Type-II excitons. We f nd remarkable differences in the transport properties of these excitons. Our studies show that bulk free-exciton transport exhibits an anomalous laser power-dependent diffusivity, whereas quasi-2D interfacial excitons and Type-II cross-interface excitons do not. Additionally, we observe localization of cross-interface excitons at the potential disorder induced by the heterointerface roughness.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 409-417
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photophysical Properties of Diphenylacetylene and Diphenylbutadiyne Derivatives in Solution Phase
Autorzy:
Hirata, Y.
Okada, T.
Nomoto, T.
Powiązania:
https://bibliotekanauki.pl/articles/1992658.pdf
Data publikacji:
1998-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.70.Hq
78.47.+p
Opis:
By using the femtosecond and picosecond transient absorption measurement techniques, we have investigated diphenylacetylene, diphenylbutadiyne, and their methoxy and cyano derivatives in the solution phase. Both the rapid S$\text{}_{2}$ → S$\text{}_{1}$ internal conversion in the subpicosecond time scale and the triplet formation in the tens of picosecond region were observed for diphenylbutadiyne and its methoxy derivatives, while the dynamic behavior of dimethoxy-diphenylacetylene was quite similar to that of diphenyl acetylene. The level inversion of the lowest excited singlet states of dicyano-diphenylbutadiyne was observed. The thermally activated S$\text{}_{2}$ ← S$\text{}_{1}$ internal conversion was not negligible and the sum of the rate constants of S$\text{}_{2}$ → S$\text{}_{1}$ and S$\text{}_{2}$ ← S$\text{}_{1}$ internal conversions was estimated to be about 5 × 10$\text{}^{11}$ s$\text{}^{-1}$ at room temperature.
Źródło:
Acta Physica Polonica A; 1998, 94, 4; 627-636
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dynamics of the Electric Field in a GaAs/AlGaAs Superlattice after Femtosecond Optical Excitation: Application of Time-Resolved Spectroscopic Techniques
Autorzy:
Lisauskas, A.
Blöser, C.
Sachs, R.
Roskos, H.
Juozapavičius, A.
Valušis, G.
Köhler, K.
Powiązania:
https://bibliotekanauki.pl/articles/1178281.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.65.Sq
78.47.+p
Opis:
We apply time-resolved photocurrent and differential electroreflectance spectroscopy to study the evolution of the internal field in a GaAs/AlGaAs superlattice after pulsed optical excitation at low temperature. The electric field dynamics is investigated by tracing the spectral position of the Wannier-Stark transitions as a function of delay time. We determine the electron sweep-out time, extract detailed information about the picosecond-time-scale drift of the charge carriers by comparing the measured data with the results of semi-classical self-consistent model calculations, and evaluate the two experimental techniques with respect to their ability to provide information about the carrier and field dynamics.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 250-255
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence Studies of Cubic Phase GaN Grown by Molecular Beam Epitaxy on (001) Silicon Covered with Sic Layer
Autorzy:
Godlewski, M.
Ivanov, V. Yu.
Bergman, J. P.
Monemar, B.
Barski, A.
Langer, R.
Powiązania:
https://bibliotekanauki.pl/articles/1968103.pdf
Data publikacji:
1997-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
78.47.+p
Opis:
In this work we evaluate optical properties of cubic phase GaN epilayers grown on top of (001) silicon substrate prepared by a new process. Prior to the growth Si substrate was annealed at 1300-1400°C in propane. The so-prepared substrate is covered with a thin (≈ 4 nm) SiC wafer, which allowed a successful growth of good morphological quality cubic phase GaN epilayers. The present results confirm recent suggestion on smaller ionization energies of acceptors in cubic phase GaN epilayers.
Źródło:
Acta Physica Polonica A; 1997, 92, 4; 777-780
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Third-Order Nonlinear Optical Properties of Pseudoazulenes
Autorzy:
Samoć, M.
Świątkiewicz, J.
Samoć, A.
Luther-Davies, B.
Olszowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1933601.pdf
Data publikacji:
1995-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.65.-k
78.47.+p
Opis:
The hyperpolarizabilities of several pseudoazulenes are evaluated using a semiempirical quantum chemistry package MOPAC-93 and compared with hyperpolarizabilities of simple molecules like chloroform, benzene, naphthalene and azulene. The third-order hyperpolarizability γ is measured for a derivative of 1,2-5,6 dibenzoxalene using a femtosecond Z-scan method at 800 nm. The resulting hyperpolarizability of 1.7×10-34 esu corroborates the theoretical prediction that pseudoazulene structures behave similar to other aromatic molecules provided the experiments are carried out in a non-resonant regime.
Źródło:
Acta Physica Polonica A; 1995, 88, 2; 411-416
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultrafast Energy Relaxation and Excitation Delocalization in Excited States of Zinc Porphyrin Dimers and Trimer
Autorzy:
Yamazaki, I.
Akimoto, S.
Yamazaki, T.
Shiratori, H.
Osuka, A.
Powiązania:
https://bibliotekanauki.pl/articles/1994082.pdf
Data publikacji:
1999-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
31.50.+w
78.47.+p
Opis:
Ultrafast excited-state relaxation process has been studied with zinc porphyrin dimers and circular trimer. Following 80 fs excitation at Soret band (420 nm) or Q band (580 nm) of zinc porphyrin, the fluorescence decay curves exhibit ultrafast decays with lifetimes of 80 fs in o-dimer, 450 fs in trimer and 540 fs in m-dimer. The timeresolved fluorescence spectra show that the fast decay process correspond to disappearance of monomer-like emission followed by red-shifted and broaden spectra. These ultrafast processes are assigned as due to excitation transfer among monomers and delocalization of excitation yielding excitonic states.
Źródło:
Acta Physica Polonica A; 1999, 95, 1; 105-120
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optically Induced Gaps in Disordered Semiconductors
Autorzy:
Kalvová, A.
Velický, B.
Powiązania:
https://bibliotekanauki.pl/articles/1950915.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
71.25.-s
Opis:
On the example of an explicitly solvable model of a semiconductor with alloy disorder in the conduction band, it is shown that a slowly varying exciting light pulse can be treated in an adiabatic approximation, that is, the self-energy of an electron can be taken as a continuously evolving series of snapshots of self-energies corresponding to a steady illumination with the instantaneous value of the light strength.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 837-842
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Bound Exciton Luminescence in Phosphorus Doped Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Crystals
Autorzy:
Van Khoi, Le
Gałązka, R. R.
Witkowska, B.
The Khoi, Nguyen
Powiązania:
https://bibliotekanauki.pl/articles/1991563.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Eq
78.47.+p
Opis:
Measurement of photoluminescence as a function of temperature and of magnetic field in p-type phosphorus doped Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te is reported. From the conduction band-acceptor level transition, the ionization energy of P-acceptors is obtained to be 54ą1 meV. The photoluminescence spectrum in the band edge region exhibits three maxima connected with the recombination of excitons bound to neutral acceptors (A$\text{}^{0}$, X), excitons bound to neutral donors (D$\text{}^{0}$,X), and free excitons (X) at energies E$\text{}_{(A^{0},X)}$=1.606, E$\text{}_{(D^{0},X)}$=1.610, and E$\text{}_{X}$=1.614 eV, respectively. At T=1.4 K a strong increase in PL intensity of (A$\text{}^{0}$, X) line 8-fold as a function of magnetic field is found and shown to originate from the magnetic field-induced lowering of the acceptor binding energy and increase in the hole effective volume.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 392-396
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence in Highly Excited InGaN/GaN Multiple Quantum Wells Grown on GaN and Sapphire Substrates
Autorzy:
Miasojedovas, S.
Juršėnas, S.
Kurilčik, G.
Žukauskas, A.
Ivanov, V. Yu.
Godlewski, M.
Leszczyński, M.
Perlin, P.
Suski, T.
Powiązania:
https://bibliotekanauki.pl/articles/2038288.pdf
Data publikacji:
2004-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.45.+h
78.47.+p
78.67.De
Opis:
We report on high-excitation luminescence spectroscopy in In$\text{}_{x}$Ga$\text{}_{1-x}$N/GaN multiple quantum wells grown by MOCVD over sapphire and bulk GaN substrates. High excitation conditions enabled us to achieve a screening of the built-in field by free carriers. This allowed for the evaluation of the influence of band potential fluctuations due to the variation in In-content on efficiency of spontaneous and stimulated emission. InGaN/GaN multiple quantum wells grown on bulk GaN substrate exhibit a significantly lower stimulated emission threshold and thus enhanced lateral emission. Transient and dynamic properties of luminescence indicate a significant reduction in compositional disorder in homoepitaxially grown structures
Źródło:
Acta Physica Polonica A; 2004, 106, 2; 273-279
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Femtosecond Dynamics of Neutral and Charged Exciton Absorption in Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te Quantum Well
Autorzy:
Płochocka, P.
Kossacki, P.
Maślana, W.
Radzewicz, C.
Gaj, J. A.
Cibert, J.
Tatarenko, S.
Powiązania:
https://bibliotekanauki.pl/articles/2035611.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.40.Fy
78.47.+p
78.67.De
Opis:
We present a study of time-dependent transmission spectra of a modulation-doped Cd$\text{}_{1-x}$Mn$\text{}_{x}$Te/Cd$\text{}_{1-y-z}$Zn$\text{}_{y}$Mg$\text{}_{z}$Te quantum well with variable hole gas concentration. We study the influence of pump pulses on excitonic absorption in subpicosecond time scale. A spectrally broad probe pulse of duration of 40 femtoseconds was used to record the absorption spectra at controlled delay. Studies of temporal evolution of exciton energies revealed coherence decay of linearly polarized excitons and thermalization of non-equilibrium exciton states. We found that a characteristic timescale for thermalization of non-equilibrium populations of photocreated excitons is between 0.8 and 3.6 ps. The timescale of this process depends on the hole concentration in quantum well: for higher hole concentration the decay is faster. Long-lived photo-induced magnetization accompanied by heating of the magnetic system was also observed.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 679-686
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long Decays of Excitonic Photoluminescence from CdTe/ZnTe Individual Quantum Dots
Autorzy:
Piechal, B.
Suffczyński, J.
Trajnerowicz, A.
Goryca, M.
Kossacki, P.
Golnik, A.
Gaj, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/2044525.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
78.67.Hc
78.55.Et
Opis:
We present time-resolved micro-photoluminescence study of self-assembled CdTe/ZnTe quantum dots. In addition to the fast radiative decay of the exciton, we observe long components, being of the order of a few nanoseconds. We observe that long decays are present for neutral exciton lines as well as on the biexciton ones. The temperature dependent measurements reveal the non-monotonic behaviour. We find also that the long decays are not mono-exponential. We conclude that the dark exciton states cannot be treated as the only source of long decays in the luminescence. We propose other possible explanation, which is the slowing of luminescence by carrier trapping in high energy states in quantum dots and barriers.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 831-836
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optical Study of an Asymmetric Double Quantum Well System: CdTe/CdMnTe
Autorzy:
Lawrence, I.
Feuilet, G.
Tuffigo, H.
Bodin, C.
Cibert, J.
Rühle, W. W.
Powiązania:
https://bibliotekanauki.pl/articles/1861487.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Hf
78.20.Ls
78.47.+p
Opis:
Carrier tunneling through CdMnTe barriers of different thicknesses is investigated in CdTe/CdMnTe asymmetric double quantum wells. Steady-state photoluminescence at 1.8 K and time-resolved photoluminescence experiments between 10 K and 50 K were performed.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 637-640
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Luminescence Decay in Deep Quantum Wells CdTe/Cd_{0.5}Mn_{0.5}Te at Room Temperature
Autorzy:
Kowalczyk, L.
Fancey, S.
Buller, G.
Massa, J.
Kutrowski, M.
Janik, E.
Karczewski, G.
Wojtowicz, T.
Zakrzewski, A.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1876908.pdf
Data publikacji:
1995-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Hf
78.47.+p
78.55.Et
Opis:
Time-resolved photoluminescence was used to study exciton recombination in deep CdTe/Cd_{0.5}Mn_{0.5}Te single quantum well. The width of the investigated well was 100 A. The study was performed at room temperature. The lifetime of the exciton determined in this work has a value comparable to that observed in shallow CdTe/Cd_{0.85}Mn_{0.15}Te quantum wells. A strong enhancement of the photoluminescence decay time with increasing intensity of the exciting laser beam is observed which is indicative of saturation of the non-radiative recombination centers.
Źródło:
Acta Physica Polonica A; 1995, 87, 2; 508-513
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Stimulated Emission in InGaN/GaN Multiple Quantum Wells with Different Indium Content
Autorzy:
Miasojedovas, S.
Juršėnas, S.
Kurilčik, G.
Žukauskas, A.
Springis, M.
Tale, I.
Yang, C. C.
Powiązania:
https://bibliotekanauki.pl/articles/2041743.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.45.+h
78.47.+p
78.67.De
Opis:
We report on high-excitation luminescence spectroscopy of In$\text{}_{x}$Ga$\text{}_{1-x}$N/GaN multiple quantum wells with a high indium content (x=0.22÷0.30). High excitation conditions enabled us to achieve screening of built-in field by free carriers. This allowed for the evaluation of the influence of the band potential fluctuations due to variation in In-content on optical properties. Enhanced spontaneous emission was found for x≫0.22 due to carrier localization within the chaotic band potential. Meanwhile the stimulated emission was found to be the highest for structures with x≈ 0.25-0.27. We attribute the In-content dependence of the stimulated emission intensity to a trade-off between an increased carrier density and a decrease in the density of states.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 256-260
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Lifetime Measurements of the $\text{}^{4}$S $\text{}_{3}\text{}_{/}\text{}_{2}$ Level in Erbium Pentaphosphate Monocrystal
Autorzy:
Kaczmarek, F.
Malak, H.
Powiązania:
https://bibliotekanauki.pl/articles/1945416.pdf
Data publikacji:
1996-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.47.+p
78.55.Hx
42.70.Hj
Opis:
Lifetime of the main fluorescence level, $\text{}^{4}$S $\text{}_{3}\text{}_{/}\text{}_{2}$ , of erbium pentaphosphate monocrystal was measured to be 380±20 ns. Direct excitation to higher energy levels, and also indirect excitation with the use of an infrared beam were applied.
Źródło:
Acta Physica Polonica A; 1996, 89, 5-6; 669-674
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Observation of Second-Generation Nonequilibrium Phonons in Highly Photoexcited CdS Microcrystals
Autorzy:
Kurilc̆ik, G.
Strumskis, M.
Jurs̆ėnas, S.
Z̆ukauskas, A.
Powiązania:
https://bibliotekanauki.pl/articles/1952036.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.Kr
78.47.+p
78.55.Et
Opis:
Luminescence kinetics of nonthermalized electron-hole plasma in highly excited CdS microcrystals embedded in glass was studied at T=295 K using two pump pulses technique. The observed carrier kinetics shows additional increase in the effective temperature during the pump pulse as a result of the prepump pulse. The increase is shown to be produced by a fusion of long-lived second-generation nonequilibrium phonons generated by the prepump pulse. The experimental results are in good agreement with a model of hot electron-hole plasma energy relaxation with a build-up of two generations of nonequilibrium phonons.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 875-878
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transient Photoconductivity and Photoluminescence in InP:Cu
Autorzy:
Stalnionis, A.
Adomavic̆ius, R.
Krotkus, A.
Marcinkevic̆ius, S.
Leon, R.
Jagadish, C.
Powiązania:
https://bibliotekanauki.pl/articles/1952097.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.40.+w
78.47.+p
78.55.-m
Opis:
Nonequilibrium photoexcited carrier dynamics in InP:Cu was investigated by two experimental techniques: the time-resolved photoluminescence up-conversion and the transient photoconductivity measurement. Both measurements show that doping with copper significantly modifies the photoexcited carrier relaxation in indium phosphide. There are several strong indications that this effect originates from the carrier trapping at metallic precipitates.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 931-934
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Inter-Island Energy Transfer in AlGaAs/GaAs Quantum Wells Grown by Molecular Beam Epitaxy
Autorzy:
Godlewski, M.
Holz, P. O.
Bergman, J. P.
Monemar, B.
Regiński, K.
Bugajski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1952469.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Fd
78.47.+p
73.20.Jc
Opis:
The results of photoluminescence, time-resolved photoluminescence, photoluminescence excitation and photoluminescence kinetics studies are presented for a Al$\text{}_{0.3}$Ga$\text{}_{0.7}$As/GaAs quantum well system grown without growth interruptions at the interfaces. The time-resolved photoluminescence measurements show drift of excitons towards lower energy states induced in a quantum well by potential fluctuations. We present also a first direct evidence for migration of free excitons from the 24 to 25 ML regions of the quantum well and interpret these results within a linear rate model, deriving the transition rate of 290 ps$\text{}^{-1}$. Such inter-island migration processes have been observed till now only in growth interrupted structures.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 1007-1011
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-25 z 92

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