Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl

Refine search results

Journals help

  1. 140 Acta Physica Polonica A

Years help

  1. 2 2018

  2. 1 2017

  3. 4 2016

  4. 1 2015

  5. 3 2014

More...
Authors help

  1. 32 Karczewski G.

  2. 31 Godlewski M.

  3. 22 Kossacki P.

  4. 21 Wojtowicz T.

  5. 16 Kossut J.

More...
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 140

Number of results on page
first rewind previous Page / 7 next fast forward last

Search results

Search:
in the keywords:  78.55.Et
help Sort By:

help Limit search:
first rewind previous Page / 7 next fast forward last
1
Content available remote

Diluted Magnetic Semiconductor Investigations in Ukraine. Nature of Some Additional Lines in QW Optical Spectra

100%
Ryabchenko S., Abramishvili V., Komarov A., Semenov Y., Kyrychenko F., Dubowski J.
Acta Physica Polonica A
|
1998
|
vol. 94
|
issue 2
165-176
EN
The general review of the history and present-day situation of diluted magnetic semiconductor investigation in Ukraine is given by S. Ryabchenko. Some noteworthy results of diluted magnetic semiconductor investigation obtained in Ukraine are pointed out. The main features of the present day situation are mentioned also. As an example of last diluted magnetic semiconductor investigations, the new result obtained by Abramishvili, Komarov, Ryabchenko, Semenov, Kyrychenko and Dubowski for Cd_{1-x}Mn_{x}Te/CdTe/Cd_{1-x}Mn_{x}Te quantum well structures grown by laser ablation method are presented. A weak additional line was observed in the reflectivity spectra of a 27 Å wide quantum well with x= 0.11 in the barrier. Such additional line has not been observed in spectra of similar molecular beam epitaxy grown structures. Based on the theoretical computations of the energies and the relation of intensities of the main and additional lines we conclude that this line might be associated with hh2 → e1 transitions, which ceases to be forbidden in the presence of technologically caused asymmetry of quantum well potential profile.
2
Content available remote

Optically Detected SdH Oscillations in CdTe/(CdMg)Te and CdTe/(CdMnMg)Te Modulation Doped Quantum Wells

100%
Shen J. X., Ossau W., Fischer F., Waag A., Landwehr G.
Acta Physica Polonica A
|
1995
|
vol. 88
|
issue 5
1033-1037
EN
Oscillations of photoluminescence properties in external magnetic fields are investigated in CdTe modulation doped quantum wells. The oscillatory behaviour of the luminescence intensity, the line width and the g factor is due to many-body effects in the 2-dimensional electron gas. The oscillation of photoluminescence intensity can be easily used as optically detected Shubnikov de Haas effect to determine the electron concentration in quantum wells without contacts.
3
Content available remote

Effect of Magnetic Polaron Formation on the Exciton Mobility Edge in Cd_{1-x}Mn_{x}Te

100%
Mackh G., Yakovlev D., Ossau W., Waag A., Landwehr G.
Acta Physica Polonica A
|
1995
|
vol. 87
|
issue 1
265-268
EN
We study the exciton localization in the semimagnetic semiconductor Cd_{1-x}Mn_{x}Te by selective excitation of the exciton photoluminescence. We show that the energy position of the effective mobility edge for excitons is subject to the competition between nonmagnetic and magnetic localization due to the magnetic polaron formation. External magnetic fields affect this competition by suppressing the polaron formation, which shifts the mobility edge.
4
Content available remote

Strain Relaxation Induced Red Shift of Photoluminescence of CdZnSe/ZnSe Quantum Wires

100%
Straub H., Brunthaler G., Faschinger W., Bauer G., Vieu C.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 5
1085-1089
EN
Wire patterns (80-1000 nm) of molecular beam epitaxy grown Cd_{0.2}Zn_{0.8}Se/ZnSe quantum well were fabricated by a CH_{4}/H_{2} reactive ion etching technique. Photoluminescence emission shows with decreasing lateral size a broadening of line shape and a spectral red shift. Calculations for the change of the band gap due to strain relaxation show that this shift of the photoluminescence emission for narrow Cd_{0.2}Zn_{0.8}Se/ZnSe structures (lattice mismatch of 1.34%) can be explained by a partial elastic strain relaxation of the biaxially compressively strained Cd_{0.2}Zn_{0.8}Se quantum well after the patterning process.
5
Content available remote

Emission of Self-Assembled CdTe/ZnTe Quantum Dot Samples with Different Cap Thickness

63%
Nowak S.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 5
890-892
EN
Photoluminescence measurements on CdTe/ZeTe self-assembled quantum dot samples with different cap thickness values (18-110nm) were performed at 1.8 K at varying excitation levels. The shape of macrophotoluminescence spectra did not altered notably with the excitation power. The spectra exhibited interference fringes related to the total barrier thickness. Simulation of the fringes confirmed the barrier thickness determined during the growth. The minimal amplitude of the fringes was observed for the cap thickness corresponding approximately to a quarter of the emission wavelength in the barrier material. Maximum emission intensity occurred for the largest thickness of the cap, i.e., 110 nm. We attribute this result to the influence of the surface recombination centers.
6
Content available remote

Numerical Rate Equation Approach to Picosecond Charge State Dynamics in CdTe/ZnTe Quantum Dots

63%
Koperski M., Kazimierczuk T., Goryca M., Wojnar P., Golnik A., Kossacki P., Gaj J.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 5
893-895
EN
The rate equation is used for description of photoluminescence dynamics after pulsed excitation of various states of quantum dots. The picosecond dynamics of averaged charge state of quantum dot is described. We compare our simulations with the experiment and come up with the conclusion that probability of carrier capture weakly depends on quantum dot charge state and that electrons and holes are captured non-synchronously.
7
Content available remote

Effect of Preheating Temperature on Microstructure and Optical Properties of ZnO Thin Films Prepared by Sol-Gel Spin Coating Technique

63%
Ji Q.-m., Wang Y.-l., Gao X.-y., Gao H., Zhai Y.-f.
Acta Physica Polonica A
|
2016
|
vol. 129
|
issue 6
1191-1196
EN
Highly-oriented ZnO thin films prepared by using low-cost technique such as sol-gel technique are of much importance to ZnO-based white light-emitting diodes. The chose of proper preheating temperature in sol-gel technique is still critical for highly-oriented ZnO thin film so far. The mechanisms for the preheating in the formation of ZnO thin film and for the reactions involved in the sol solution have not been clearly stated yet. Thus, in this work, the highly-oriented ZnO thin films were prepared on glass substrates by using sol-gel spin-coating technique. The sol solution was prepared by using the two-step method rather than usual one-step method, which facilitates the understanding of the mechanism for the reactions involved in the sol solution. The effect of the preheating temperature on the microstructure and the optical properties of the films were in particular investigated. The mechanisms for the preheating in the formation of the films and for the reactions involved in the sol solution prepared by the two-step method were also proposed in terms of the experimental results. The preheating not only enhances the volatilization of the solvent 2-methoxyethanol and the decomposition of the residual organic species, but also results into the formation of small number of ZnO particles. The preheating temperature of 300°C is most favorable for the highly-oriented ZnO thin film. Increasing the preheating temperature results into the blue shift of the absorption edges of the films. This can be explained by using the quantum-size effect. The photoluminescence spectra of the films show an UV emission at the near-band edge and a broad green-yellow emission at 470-620 nm. The former is closely related to the excitons, while the latter is to the intrinsic defect species in the film.
8
Content available remote

Swift Xe^{26+} Ion Irradiation Effect on Luminescent Properties of Undoped and Cd-Doped ZnO Films

63%
Myroniuk D., Lashkarev G., Shtepliuk I., Skuratov V., Reszka A., Kowalski B.
Acta Physica Polonica A
|
2014
|
vol. 126
|
issue 5
1199-1202
EN
Here we report the effect of the irradiation by 167 MeV Xe^{26+} ions (in the fluence range up to 3× 10^{12} ions/cm^2) on the undoped and Cd-doped (0.4, 0.5 at.%) ZnO films deposited by radiofrequency magnetron sputtering. As-grown and irradiated samples were investigated by cathodoluminescence spectroscopy. It was found that the radiation causes a decrease in intensity of luminescent peaks and a redistribution of the radiative recombination channels. We revealed that the cadmium incorporation into ZnO lattice enhances the radiation resistance of ZnO film.
9
Content available remote

Anisotropic Exchange Interaction between p-Shell Electron and s-Shell Hole in CdTe/ZnTe Quantum Dots

63%
Kazimierczuk T., Golnik A., Goryca M., Wojnar P., Gaj J., Kossacki P.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 5
882-884
EN
We study electron-hole exchange interaction in a single CdTe/ZnTe quantum dot by polarization-resolved photoluminescence measurements. We focus on recombination of excitonic states involving p-shell electrons: X^{2-} and XX^-. Recombination lines of X^{2-} and XX^- states exhibit fine structure, which can be consistently explained within a model with four parameters δ_{i}^{αβ} representing strength of iso- and anisotropic parts of interaction between s-hole and s- or p-electron.
10
Content available remote

Graded Quantum Well Structures Made of Diluted Magnetic Semiconductors

63%
Wojtowicz T., Kutrowski M., Karczewski G., Kossut J.
Acta Physica Polonica A
|
1998
|
vol. 94
|
issue 2
199-217
EN
In this paper we review results of studies of two types of spatially graded quantum well structures containing various layers of diluted magnetic semiconductors Cd_{1-x}Mn_{x}Te or Cd_{1-x-y}Mn_{x}Mg_{y}Te. The design of the structures has been recently proposed by us and suitable samples have been grown by a modified molecular beam epitaxy method. In the structures of the first type a digital profiling of the composition of the constituent material in the growth direction allowed to produce quantum wells with a specifically required shape of the confining potential (including parabolic, half-parabolic, triangular, and trapezoidal). Such samples were used for (i) determination of the conduction and valence band offsets in MnTe/CdTe and MgTe/CdTe systems, (ii) for the demonstration of an enhanced exciton binding in a parabolic confining potential as well as for (iii) demonstration of the possibility of "spin-splitting engineering" in diluted magnetic semiconductors quantum structures. In the second type of the structures, a precise in-plane profiling of either quantum well width or the barrier width or n-type doping intensity was realized. These structures were subsequently used for studies of the evolution of optical spectra with an increase in the concentration of confined two-dimensional gas of conduction electrons.
11
Content available remote

Ionization Energies of RE Ions in wide Bandgap Sulphides

63%
Świątek K., Godlewskl M.
Acta Physica Polonica A
|
1991
|
vol. 79
|
issue 2-3
247-250
EN
An analysis of rare earth (RE) energy level positions in wide bandgap sulphides is presented. It is shown that the Jörgensen's refined spin-pairing energy theory (RESPET) predicts correctly the photo-ionization (PI) energy of Sm in ZnS.
12
Content available remote

Control of Local Electric Fields Influencing the Photoluminescence οf an Individual CdTe/ZnTe Quantum Dot

63%
Haas K., Kazimierczuk T., Wojnar P., Golnik A., Gaj J., Kossacki P.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue 5
896-898
EN
We examine the influence of a weak non-resonant illumination on the quantum dot photoluminescence spectrum. We observe that even very weak illumination affects both intensity and spectral position of emission lines in the spectrum. We discover no significant asymmetry in spatial dependence and infer that the observed effects cannot be attributed to a single neighbor center.
13
Content available remote

Study of Blue Photoluminescent Band in ZnS Crystals

63%
Liem N. Q., Quang V. X., Thanh D. X.
Acta Physica Polonica A
|
1994
|
vol. 86
|
issue 6
979-985
EN
The zinc sulphide crystals as-grown and heat treated in different atmospheres, have been studied by photoluminescence technique. A blue emission band (IB) peaking at 2.91 eV has been identified in the mentioned crystals. Parameters of the IB band such as peak energy, half width of spectrum, lifetime of photoluminescence as well as a superlinearly excitation intensity dependence of the luminescence have been determined. A model of the IB transition is proposed to explain the properties and features of IB luminescence.
14
Content available remote

Effects of Ar/O_2 Gas Ratio on the Properties of the Zn_{0.9}Cd_{0.1}O Films Prepared by DC Reactive Magnetron Sputtering

63%
Shtepliuk I., Lashkarev G., Khomyak V., Marianchuk P., Koreniuk P., Myroniuk D., Lazorenko V., Timofeeva I.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 6A
A-61-A-65
EN
Zn_{0.9}Cd_{0.1}O ternary alloys have been grown on the sapphire substrates by using the direct current (dc) magnetron sputtering. X-ray diffraction measurements showed that all samples were highly oriented films along the c-axis perpendicular to the substrate surface. X-ray diffraction confirmed that the crystal quality of Zn_{0.9}Cd_{0.1}O films can be controlled by changing the gas ratio of Ar/O_2. The optical properties of these films have been investigated by means of the optical transmittance and the low-temperature photoluminescence spectra. It was found that the optical band gap of the deposited films can be tuned by growth parameters. The luminescence processes are considered in the terms of alloy fluctuation.
15
Content available remote

Photoluminescence of Donor-Doped ZnSe Films Grown by Molecular Beam Epitaxy

63%
Karczewski G., Hu B., Yin A., Luo H., Dobrowolska M., Furdyna J.
Acta Physica Polonica A
|
1995
|
vol. 87
|
issue 1
245-248
EN
We studied the effect of the donor doping of ZnSe films on their photoluminescence properties. The samples were doped during the molecular beam epitaxy growth, either with gallium or with chlorine. As the dopant concen­tration dose increases, the intensity of the band-edge emission first saturates, and then quenches in favor of the deep-level photoluminescence band. The main effect of donor doping on photoluminescence is a strong increase in intensity of the donor-bound exciton line, referred to as I_{2}. For Ga-doped films deep-band emission is much stronger, and the I_{2}-line is slightly weaker than for Cl-doped films with comparable doping level. The results confirm the superiority of chlorine over gallium as an n-type dopant in ZnSe. We dis­cuss the photoluminescence results and relate them to deep level transient spectroscopy data obtained on the same samples.
16
Content available remote

(120)-Oriented CdTe/CdMnTe Quantum Well Structures Grown by Molecular Beam Epitaxy

63%
Kutrowski M., Karczewski G., Cywiński G., Surma M., Grasza K., Łusakowska E., Kossut J., Wojtowicz T.
Acta Physica Polonica A
|
1996
|
vol. 90
|
issue 5
879-882
EN
We report on the MBE growth and magnetooptical studies of (120)-oriented CdTe/CdMnTe quantum well structures. The quality of structures, as evaluated by the photoluminescence line width, was as good as that of the best structures grown in ⟨100⟩ direction. No spin splitting enhancement, expected theoretically, due to the reduction of the antiferromagnetic interaction between Mn ions in CdTe/CdMnTe digital alloy quantum wells grown along ⟨120⟩ direction was observed.
17
Content available remote

Novel CdTe/CdMgTe Graded Quantum Well Structures

63%
Wojtowicz T., Kutrowski M., Karczewski G., Cywiński G., Surma M., Kossut J., Yakovlev D. R., Ossau W., Landwehr G., Kochereshko V.
Acta Physica Polonica A
|
1997
|
vol. 92
|
issue 5
1063-1066
EN
We report on growth and magnetooptical studies of two types of novel CdTe/CdMgTe quantum well structures having a precisely controlled grading of either the quantum well width or the donor concentration in a direction perpendicular to the growth axis. The presence of two-dimensional electron gas of varying concentration produced by the graded modulation doping was evidenced by observation of negatively charged exciton-electron complexes (X¯).
18
Content available remote

Spin in CdTe/ZnTe Quantum Dot: Its Potential for Information Storage

63%
Kazimierczuk T.
Acta Physica Polonica A
|
2009
|
vol. 116
|
issue S
S-13-S-18
EN
We present a selection of our studies on CdTe/ZnTe quantum dots considered as spin qubits. Discussed experiments are related to processes of spin reading, writing and evolution. We show that CdTe/ZnTe system is well suitable for studying effects important for optical quantum computing on single spins.
19
Content available remote

Exciton Transfer in Multiple Quantum Well Structures of CdTe/CdMnTe Grown by Molecular Beam Epitaxy

63%
Godlewski M., Surma M., Wilamowski Z., Wojtowicz T., Karczewski G., Kossut J., Holtz P. O., Bergman J. P., Monemar B.
Acta Physica Polonica A
|
1997
|
vol. 92
|
issue 4
761-764
EN
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.
20
Content available remote

Recombination Processes in Doped CdTe/CdMnTe Multiple Quantum Well Structures Grown by Molecular Beam Epitaxy

63%
Godlewski M., Wojtowicz T., Karczewski G., Kossut J., Bergman J. P., Monemar B.
Acta Physica Polonica A
|
1997
|
vol. 92
|
issue 4
757-760
EN
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.
first rewind previous Page / 7 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.