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  1. 31 Acta Physica Polonica A

  2. 1 Archives of Foundry Engineering

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  1. 32 Kowalski B.

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1
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Electronic Structure of Diluted Semimagnetic Semiconductor (Cd,Co)Se

100%
Cháb V., Mašek J., Orłowski B., Kowalski B.
Acta Physica Polonica A
|
1991
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vol. 80
|
issue 3
333-336
EN
The electronic structure of a new semimagnetic semiconductor (Cd,Co)Se is studied by UPS and calculated by a tight-binding version of the disordered-local-moment theory. The theory accounts for the chemical disorder and for electron interactions within the Co 3d^{7} shells. Both theory and experiment show Co 3d states deep in the valence band and also at the band edge. The last state seem to be responsible for unique properties of the Co-based semimagnetic semiconductors.
2
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Reflectivity Study of the Zn_{1-x}Co_{x}Se Crystals

100%
Kowalski B., Gołacki Z., Orłowski B.
Acta Physica Polonica A
|
1991
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vol. 80
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issue 3
393-396
EN
The room temperature reflectivity spectra of the Zn_{1-x}Co_{x}Se (x = 0, 0.03, 0.05) crystals have been measured in the visible and ultraviolet range from 1.7 to 12 eV. The structure of the spectra was interpreted in terms of the electronic band structure of the binary material (ŻnSe). The experimental results were compared with the reflectivity spectra of the Fe-based semi magnetic semiconductors [1], and the interpretation was confronted with the conclusions derived from the photoemission experiments performed for Cd_{1-x}Co_{x}Se [2] and the tight-binding CPA calculations of the band structure of Zn_{1-x}Co_{x}Se [3].
3
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Reflectivity Study of HgSe_{1-x}Te_{x} Crystals

100%
Kowalski B., Dybko K., Lemańska A., Orłowski B.
Acta Physica Polonica A
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1992
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vol. 82
|
issue 5
845-848
EN
The room temperature reflectivity spectra of HgSe_{1-x}Te_{x} (x = 0, 0.4, 0.5, 1.0) crystals were measured in the visible and ultraviolet range from 1.5 to 12 eV. The maxima characteristic of the binary HgA^{IV} compounds can be revealed in the mixed crystals spectra, but their position depends on the crystal composition. There is no duplication of the spectral features in spite of the different energy position of the maxima for HgSe and HgTe. This suggests that the virtual crystal approximation could be used to describe basic optical properties of HgSe_{1-x}Te_{x}.
4
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Resonant Photoemission Study οf 4f Electrons on the Surface οf Semiconductors

100%
Orłowski B., Kowalski B., Pietrzyk M., Buczko R.
Acta Physica Polonica A
|
2008
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vol. 114
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issue S
S-103-S-114
EN
The contribution of 4f electrons to the electronic structure of the semiconductor clean surface caused by the surface doping of it by rare-earth metal atoms (Eu, Sm) will be presented. The surface doping was performed by the controlled, sequential deposition of the rare-earth metal atoms on the clean surface in UHV conditions (Sm on GaN or CdTe) or by the doping of the layer volume of (EuGd)Te. After each deposition or surface treatment the synchrotron radiation was used to measure in situ the resonant photoemission spectra (the Fano type resonance) to study the contribution of 4f electrons of divalent and trivalent Sm and Eu ions to the valence band electronic structure of created sample. The first stages of the metal atoms deposition lead to the surface doping. Further metal atoms deposition leads to the growth of the metallic islands on the surface and causes the appearance of the sharp metallic Fermi edge in the energy distribution curves. Proper coverage and annealing of the sample surface with metal atoms leads to the diffusion of the metal atoms into the sample and results in an increase in the crystal doping and decrease in the metallic islands contribution to the measured spectra. As a result, the new electronic structure of the valence band can be created and investigated in situ.
5
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Microstructural and Tribological Characterization of Aluminium Bronzes with Additions of Si and Cr

88%
Pisarek B. P., Kowalski B., Atapek H., Polat Ş., Tüfekçi T.
Archives of Foundry Engineering
|
2018
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issue 1
6
Content available remote

Contribution of Mn 3d Electrons To the Valence Band of Sn_{0.9}Mn_{0.1}te

88%
Nadolny A., Guziewicz E., Kowalski B., Orłowski B., Johnson R.
Acta Physica Polonica A
|
1998
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vol. 94
|
issue 3
454-458
EN
The synchrotron radiation in the energy range between 15 and 70 eV was used to investigate the electronic structure of the crystalline Sn_{0.9}Mn_{0.1}Te by means of the resonant photoemission spectroscopy. Fano-type resonance has been observed in the obtained constant initial energy curves with the resonant energy 50.6 eV and antiresonant energy 49.0 eV. The energy distribution curves taken at photon energies close to the Mn 3p-3d transitions allow us to conclude that Mn atoms contribute to the valence band mainly at energies of 4.0 eV and 7.8 eV below the valence band edge.
7
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Band Structure of Mn/ZnTe Studied, by Angle-Resolved Photoelectron Spectroscopy

76%
Kowalski B., Orlowski B., Pietrzyk M., Kaczor P., Kopalko K., Mickievicius S., Johnson R.
Acta Physica Polonica A
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2005
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vol. 108
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issue 5
735-740
EN
The electronic band structure of Mn/ZnTe(110) (1×1) has been studied by angle-resolved photoelectron spectroscopy. The sets of spectra were acquired for the clean surface and after in situ deposition of 0.4 ML of Mn, in order to compare the band structures and to reveal changes brought about by the presence of Mn. The experimental band structure diagram of Mn/ZnTe along theΓ-K direction in the Brillouin zone has been derived from the experimental data. Indications of interaction between the Mn 3d states and sp^3 bands of the semiconductor are discussed.
8
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Angle-Resolved Photoelectron Spectroscopy on CdTe(100) c(2×2)

76%
Gawlik K., Brügmann J., Harm S., Manzke R., Skibowski M., Kowalski B., Orłowski B.
Acta Physica Polonica A
|
1993
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vol. 84
|
issue 6
1093-1099
EN
The CdTe(100) c(2×2) surface prepared by ion bombardment and annealing was investigated by angle-resolved photoemission spectroscopy using synchrotron radiation with photon energies between 8.5 eV and 32 eV. The bulk band structure was determined along the ΓΔX-direction normal to the surface measuring energy-distribution curves. The results are compared with a theoretical valence band structure assuming free-electron-like final states in connection with k-conservation. For further comparison we calculated the final states by the pseudopotential method and analyzed the results in form of structure plots. In this way, most of the dispersing maxima in the normal emission spectra can be explained. For this mode of photoelectron spectroscopy the resulting dispersion must be due to the component of the Bloch wave vector normal to the surface, k_{⊥}, keeping surface related structures at a fixed binding energy position E_{b}. The lack of dispersion for five structures along ΓΔX gives experimental evidence for their surface origin.
9
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Fe 3d Contribution to Hg_{1-x}Fe_{x}Se Valence Band by Means of Angle-Resolved Photoemission

76%
Orłowski B., Bonnet J., Hricovini C., Pinchaux R., Górecka J., Kowalski B., Mycielski A.
Acta Physica Polonica A
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1991
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vol. 80
|
issue 3
389-392
EN
The Angle-Resolved Photoemission Electron Spectroscopy (AR PES) was applied to investigate the electronic structure of HgSe and Hg_{1-x}Fe_{x}Se crystals for (110) surface. The measured set of Angle-Resolved Energy Distribution Curves (AR EDCs) permits to determine some of the elements of the electronic band structure E(k) (energy-momentum dependence for ҐKX and ҐX directions in the Brillouin zone) for measured crystals. The Fe 3d contribution gives the states lying over the edge of the valence band of HgSe crystal (0.25 eV), and into the valence band.
10
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Cathodoluminescence Profiling for Checking Uniformity of ZnO and ZnCoO Thin Films

76%
Witkowski B., Łukasiewicz M., Wolska E., Kopalko K., Kowalski B., Guziewicz E., Godlewski M.
Acta Physica Polonica A
|
2011
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vol. 119
|
issue 5
675-677
EN
We employ scanning electron microscopy and cathodoluminescence for evaluation of uniformity of ZnCoO films obtained by the atomic layer deposition. Cathodoluminescence quenching by Co ions allows us to detect (regions of weaker light emission) Co accumulations, with the resolution limited by diffusion length of secondary carriers.
11
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Resonant Photoemission Study of Mn 3d Electrons Contribution to the Pb_{0.92}Mn_{0.08}Se Valence Band

76%
Orłowski B., Kowalski B., Le K., Gałązka R., Ghijsen J., Johnson R.
Acta Physica Polonica A
|
1995
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vol. 87
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issue 2
329-332
EN
The resonant photoemission spectroscopy was applied to investigate the valence band electronic structure of semimagnetic semiconductor Pb_{0.92}Mn_{0.08}Se crystal and to determine the contribution of Mn 3d electrons to the valence band. The set of energy distribution curves and constant initial states spectra were taken for by energies in the region (40-60 eV) close to the Mn 3p-3d transition. The electrons Mn 3d hybridize and contribute to the valence band electrons of the crystal and main density of states contribution appears in the energy 3.5 ± 0.2 eV below the valence band edge.
12
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4f Contribution to Valence Band of Pb_{1-x}RE_{x}S (RE = Eu,Gd) Studied by Resonant Photoemission

76%
Kowalski B., Gołacki Z., Guziewicz E., Orłowski B., Ghijsen J., Johnson R.
Acta Physica Polonica A
|
1996
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vol. 90
|
issue 5
1035-1039
EN
Resonant photoemission experiments were carried out in order to reveal the contributions of partly filled Eu 4f^{7} and Gd 4f^{7} shells to the valence bands of Pb_{0.95}Eu_{0.05}S and Pb_{0.95}Gd_{0.05}S crystals. The coupling between these orbitals and the host electronic states is discussed.
13
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Electronic Band Structure of Cubic HgS

76%
Guziewicz E., Kowalski B., Orłowski B., Dybko K., Witkowska B., Szuszkiewicz W.
Acta Physica Polonica A
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1995
|
vol. 87
|
issue 2
395-398
EN
Reflectivity spectra of Hg_{1-x}Fe_{x}S (x < 0.04) and HgSe_{1-y}S_{y} (y < 0.5) mixed crystals were measured in the vacuum ultraviolet energy range from 4 to 12 eV. Information about the electronic band structure of cubic modi­fication of HgS resulting from the above data is analyzed and discussed.
14
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Visible Luminescence from Porous Silicon

76%
Bała W., Firszt F., Nossarzewska-Orłowska E., Brzozowski A., Orłowski B., Kowalski B., Guziewicz E.
Acta Physica Polonica A
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1993
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vol. 84
|
issue 4
761-764
EN
This paper presents results of investigation of the temperature dependence of visible luminescence in porous silicon layers prepared by anodization in hydrofluoric acid. Luminescence spectra were measured in the temperature range between 40 K and 350 K. Room temperature reflectivity spectra were also measured in vacuum ultraviolet radiation range from 4 eV to 12 eV.
15
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Swift Xe^{26+} Ion Irradiation Effect on Luminescent Properties of Undoped and Cd-Doped ZnO Films

76%
Myroniuk D., Lashkarev G., Shtepliuk I., Skuratov V., Reszka A., Kowalski B.
|
|
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.
16
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Valence Band Density of States and Mn 3d Contribution in Mn_{1-x}Mg_{x}Te

76%
Kowalski B., Guziewicz E., Kopalko K., Orłowski B., Janik E., Wojtowicz T., Johnson R.
Acta Physica Polonica A
|
1998
|
vol. 94
|
issue 3
401-405
EN
Resonant photoemission spectroscopy was applied to determine the Mn 3d derived contribution to the valence band density of states of Mn_{0.44} Mg_{0.56}Te grown by molecular beam epitaxy on a GaAs(001) substrate. The modifications of the valence band density-of-states distribution are discussed as a consequence of the substitution of Mg ions for Mn ions.
17
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Resonant Photoemission Study of Cd_{1-x}Fe_{x}Se Valence Band

76%
Orłowski B., Fraxedas J., Denecke R., Kowalski B., Mycielski A., Ley L.
Acta Physica Polonica A
|
1991
|
vol. 79
|
issue 2-3
355-358
EN
The phenomenon of Fano type resonant photoemission was used to distinguish the Fe electrons derived partial contribution to the valence band of a semimagnetic semiconductor Cd_{1-x}Fe_{x}Se. The states appearing at the middle of the valence band correspond to the Fe 3d electrons while the step of the density of states obtained at the valence band edge region correspondsvto the hybridized s-p-d electrons.
18
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Magnetic Properties of Sn_{1-x}Cr_xTe Diluted Magnetic Semiconductors

64%
Kilanski L., Podgórni A., Górska M., Dobrowolski W., Slynko V., Slynko E., Reszka A., Kowalski B.
Acta Physica Polonica A
|
2013
|
vol. 124
|
issue 5
881-884
EN
We present the studies of Sn_{1-x}Cr_xTe semimagnetic semiconductors with chemical composition x ranging from 0.004 to 0.012. The structural characterization indicates that even at low average Cr-content x ≤q 0.012, the aggregation into micrometer size clusters appears in our samples. The magnetic properties are affected by the presence of clusters. In all our samples we observe the transition into the ordered state at temperatures between 130 and 140 K. The analysis of both static and dynamic magnetic susceptibility data indicates that the spin-glass-like state is observed in our samples. The addition of Cr to the alloy seems to shift the spin-glass-like transition from 130 K for x = 0.004 to 140 K for x = 0.012.
19
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Enhancement of the Ultraviolet Luminescence Intensity from Cd-Doped ZnO Films Caused by Exciton Binding

64%
Shtepliuk I., Lashkarev G., Khyzhun O., Kowalski B., Reszka A., Khomyak V., Lazorenko V., Timofeeva I.
Acta Physica Polonica A
|
2011
|
vol. 120
|
issue 5
914-917
EN
ZnO films doped with the cadmium (0.4-0.6%) were grown on crystalline sapphire c-Al_2O_3 substrates applying radiofrequency magnetron sputtering at the temperature of 400°C in Ar-O_2 atmosphere. The as-grown films were investigated in detail using X-ray diffraction, X-ray photoelectron spectroscopy, and cathodoluminescence spectra. The X-ray diffraction analysis revealed that the films possess a hexagonal wurtzite-type structure with the dominant crystallite orientation along the c axis. It was found that the small concentration of the cadmium significantly enhances the ultraviolet emission associated with excitonic transitions. We suggest that this enhancement effect mainly results from appearance of the cadmium isoelectronic traps, which may bind an exciton, thereby increasing the probability of radiation recombination. The effect of Cd isoelectronic impurity on structural and luminescent properties of ZnO films is discussed.
20
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Content available

Fano Resonance of Eu^{2+} and Eu^{3+} in (Eu,Gd)Te MBE Layers

64%
Orlowski B., Kowalski B., Dziawa P., Pietrzyk M., Mickievicius S., Osinniy V., Taliashvili B., Kowalik I., Story T., Johnson R.
Acta Physica Polonica A
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2005
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vol. 108
|
issue 5
803-807
EN
Resonant photoemission spectroscopy, with application of synchrotron radiation, was used to study the valence band electronic structure of clean surface of (EuGd)Te layers. Fano-type resonant photoemission spectra corresponding to the Eu 4d-4f transition were measured to determine the contribution of 4f electrons of Eu^{2+} and Eu^{3+} ions to the valence band. The resonant and antiresonant photon energies of Eu^{2+} ions were found as equal to 141 V and 132 eV, respectively and for Eu^{3+} ions were found as equal to 146 eV and 132 eV, respectively. Contribution of Eu^{2+}4f electrons was found at the valence band edge while for Eu^{3+} it was located in the region between 3.5 eV and 8.5 eV below the valence band edge.
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