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Wyszukujesz frazę "79.60.Jv" wg kryterium: Temat


Tytuł:
Zn(Mn)O Surface Alloy Studied by Synchrotron Radiation Photoemission
Autorzy:
Guziewicz, E.
Kopalko, K.
Sadowski, J.
Guziewicz, M.
Golacki, Z.
Powiązania:
https://bibliotekanauki.pl/articles/2043720.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.-r
79.60.-i
79.60.Jv
Opis:
The Mn/ZnO(0001) system was investigated by synchrotron radiation photoemission. The Mn/ZnO interface with 4 ML of manganese deposited onto the ZnO surface was annealed up to 500ºC. No Mn capping layer was found at the surface after annealing as was confirmed by scanning Auger spectroscopy experiment. We used a resonant photoemission to extract the Mn3d partial density of states in photoemission spectra. The Mn3d states contribute to the electronic structure of the system within 10 eV of the Fermi level. They show three features: a main peak at 3.8-4.5 eV, a valence structure at the top of the valence band (1-3 eV), and a broad satellite situated between 5.5 and 9 eV below E$\text{}_{F}$. The satellite/main branching ratio was determined to be 0.43, which is a fingerprint of strong hybridization between the Mn3d electrons and the valence band of the crystal. The hybridization effect in Zn$\text{}_{1-x}$ Mn$\text{}_{x}$O surface alloy is comparable to Zn$\text{}_{1-x}$Mn$\text{}_{x}$S and much higher than in Zn$\text{}_{1-x}$Mn$\text{}_{x}$Se, Zn$\text{}_{1-x}$Mn$\text{}_{x}$Te, and Ga$\text{}_{1-x}$Mn$\text{}_{x}$As semimagnetic compounds.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 689-696
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ultra Fine-Grained Metals Prepared by Severe Plastic Deformation: A Positron Annihilation Study
Autorzy:
Čížek, J.
Procházka, I.
Kužel, R.
Matĕj, Z.
Cherkaska, V.
Cieslar, M.
Smola, B.
Stulíková, I.
Brauer, G.
Anwand, W.
Islamgaliev, R. K.
Kulyasova, O.
Powiązania:
https://bibliotekanauki.pl/articles/2043303.pdf
Data publikacji:
2005-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
79.60.Jv
Opis:
Recent investigations of ultra fine-grained metals (Cu, Fe, Ni) performed within a Prague-Rossendorf-Ufa collaboration will be reviewed. The specimens were prepared by severe plastic deformation: the high-pressure torsion and equal channel angular pressing. Positron annihilation spectroscopy was used as the main method including (i) the conventional lifetime and the Doppler broadening measurements with $\text{}^{22}$Na and (ii) the slow-positron implantation spectroscopy with the Doppler broadening measurement. Other methods were also involved: transmission electron microscopy, X-ray diffraction, and microhardness. First, the mean grain size was determined and defects were identified in the as-deformed materials. Defects concentration and spatial distribution were studied in detail. Dislocations situated in distorted regions along grain boundaries, and a few-vacancy clusters distributed homogeneously inside dislocations-free grains, were observed in the ultra fine-grained Cu, Fe, and Ni. Subsequently, the thermal evolution of the ultra fine-grained structures during isochronal annealing was studied.
Źródło:
Acta Physica Polonica A; 2005, 107, 5; 745-752
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Positron Lifetime Spectroscopy of Nanocrystalline Copper
Autorzy:
C̆ížek, J.
Procházka, I.
Vostrý, P.
Chmelík, F.
Islamgaliev, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/2007957.pdf
Data publikacji:
1999-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
79.60.Jv
Opis:
Positron lifetime spectroscopy was applied to investigate the thermal stability of nanocrystalline copper prepared by severe plastic torsion deformation. Positrons annihilating in as prepared specimens exhibited free positron component τ$\text{}_{1}$ and two defect components τ$\text{}_{2}$=164 ps and τ$\text{}_{3}$=255 ps. Evolution of the lifetimes and relative intensities of all the three components with increasing annealing temperature during step-by-step isochronal annealing up to 630°C was studied. Behaviour of positrons in nanocrystalline copper could not be interpreted in the frame of conventional 3-state trapping model due to highly inhomogeneous defect distribution. Therefore a modified trapping model was developed and applied to explain the experimental results.
Źródło:
Acta Physica Polonica A; 1999, 95, 4; 487-495
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoexcitation Spectroscopy and Material Alteration with Free-Electron Laser
Autorzy:
Sturmann, J.
Albridge, R. G.
Barnes, A. V.
Gilligan, J.
Graham, M. T.
Mckinley, J. T.
Ueda, A.
Wang, W.
Yang, X.
Tolk, N. H.
Davidson, J. L.
Margaritondo, G.
Powiązania:
https://bibliotekanauki.pl/articles/1963341.pdf
Data publikacji:
1997-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.20.La
79.20.Ds
63.20.-e
79.60.Jv
73.20.At
Opis:
As synchrotron radiation sources have been used for many experiments in the ultraviolet and X-ray regimes, the free-electron laser is an excellent source for a wide array of infrared-photon projects and applications. The free-electron laser delivers a beam of powerful tunable pulsed radiation which provides the opportunity for spatial and temporal localization of the energy delivered at any desired wavelength within the 2-10 μ regime. One application discussed employs the free-electron laser for spectroscopy as a probe of electronic and vibrational structures. Another application uses the free-electron laser beam as a tool for altering materials in a fundamentally new way.
Źródło:
Acta Physica Polonica A; 1997, 91, 4; 689-696
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoemission Study of the Initial Growth of Co on Ru(0001)
Autorzy:
Godowski, P. J.
Onsgaard, J. J.
Trzebiatowska-Gusowska, M. J.
Pater, K. J.
Li, Zhe
Powiązania:
https://bibliotekanauki.pl/articles/2047268.pdf
Data publikacji:
2007-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Dp
79.60.Jv
68.55.Jk
Opis:
The growth process of cobalt on Ru(0001) was characterized by photoelectron spectroscopy excited by X-ray and synchrotron radiation. The binding energy position and intensity of the Co 2p$\text{}_{3}\text{}_{/}\text{}_{2}$ and Ru 3d$\text{}_{5}\text{}_{/}\text{}_{2}$ core levels as well as the shape and structure of the valence band spectra corresponding to the different stages of the deposition were investigated. An observed small positive binding energy shift is a consequence of an increase in the cobalt adatoms coordination number. The core-level shift between bulk and surface Ru atoms is determined as -360 meV. Upon adsorption of cobalt, the interface peak appears with a shift of -(70÷80) meV relative to the bulk one. On the basis of unchanged energy positions and widths of the Ru-derived features of the valence band spectra, a weak interaction between cobalt and substrate is suggested. The measured valence band could be reproduced by superimposing the spectra of the pure elements.
Źródło:
Acta Physica Polonica A; 2007, 111, 2; 263-271
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoemission Study of CO$\text{}_{2}$ adsorbed on K/Cu(110). Analysis of Adsorbate Induced Structures
Autorzy:
Godowski, P. J.
Onsgaard, J.
Hoffmann, S. V.
Nerlov, J.
Powiązania:
https://bibliotekanauki.pl/articles/2007842.pdf
Data publikacji:
1999-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Jv
33.60.-q
82.80.Pv
Opis:
Using photoemission spectroscopy, adsorption and reaction of CO$\text{}_{2}$ on potassium modified Cu(110) were studied. In agreement with published results of thermally programmed desorption, apart from carbonate and carbon monoxide as the disproportionation reaction products, a linear CO$\text{}_{2}$ molecule and a bent active CO$\text{}_{2}$(-) species were identified. The reaction paths are independent on the potassium precoverage but the number of CO$\text{}_{3}$ molecules increases with the number of potassium adatoms. The presence of the CO$\text{}_{2}$(-), stable up to 200 K, suitable for the reactivity of the interface in respect of the methanol synthesis, could be confirmed in the complex valence band spectra by occurrence of the characteristic peak at binding energy of 6.8 eV.
Źródło:
Acta Physica Polonica A; 1999, 95, 3; 423-431
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoemission Study of Co Adsorbed on K/Cu(110). Analysis of Adsorbate Induced Structures
Autorzy:
Godowski, P. J.
Onsgaard, J.
Christensen, S. V.
Nerlov, J.
Powiązania:
https://bibliotekanauki.pl/articles/1945414.pdf
Data publikacji:
1996-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Jv
33.60.-q
82.80.Pv
Opis:
Improved adsorption characteristics of a K predosed Cu(110) surface with a coverage corresponding to a point before the work function minimum have been confirmed. Analysis of the CO-induced orbitals in the photoelectron spectra of the CO/K/Cu(110) interface for low coverages of carbon monoxide adsorbed at 118 K has been done. Noticeable changes of the parameters of the orbitals with increasing CO coverage have been registered. Elongation of the C-O bond without dissociation of the molecule has been deduced from the energetic separation of 3.4 eV between the 4σ and the 1π orbital. A weakening of the CO-interface bond with coverage has been found on the base of decreasing 5σ-1π separation with increasing 4σ/5σ intensity ratio. Perpendicular orientation of CO molecules to the plane of the substrate surface has been concluded from analysis of the constant initial state spectra of the 4σ and 5σ/1π orbitals.
Źródło:
Acta Physica Polonica A; 1996, 89, 5-6; 657-664
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoemission Electronic Spectra οf CdTe/$Pb_{0.95}Eu_{0.05}Te$/CdTe
Autorzy:
Orlowski, B.
Dziawa, P.
Gas, K.
Reszka, A.
Mickievicius, S.
Thiess, S.
Drube, W.
Powiązania:
https://bibliotekanauki.pl/articles/1492971.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Jv
71.20.Mq
73.40.-c
Opis:
The synchrotron radiation was used to apply tunable high energy X-ray photoemission spectroscopy for investigation of electronic structure of semiconductor nanostructure CdTe/$Pb_{0.95}Eu_{0.05}Te$/CdTe/GaAs(001) top part. The $Pb_{0.95}Eu_{0.05}Te$ (6 nm thick) was buried under thin (22 nm) top layer of CdTe transparent for part of electrons photoemitted from $Pb_{0.95}Eu_{0.05}Te$ buried layer. The top layer of CdTe was sputtered by Ar ion bombardment for surface cleaning and for leaving the thickness of CdTe more transparent for photoelectrons emitted from buried layer. For these thickness of the top layer the photoemission energy distribution curves corresponding to the valence band and core levels electrons of the buried layer atoms were measured with application of synchrotron radiation of energy hν = 3510 eV. The measured spectra corresponding to the buried layer atoms were observed in the valence band region and in the high binding energy region for core levels of Pb 4f, Pb 3d. The valence band contribution and core levels Cd 4d and Cd 3d were obtained mainly from top cover layer. Measured Te 4d, Te 3d and Te 4d spectra possess contribution as well from top cover layer as from the buried layer. The amount of Eu atoms was to small to be reasonable detected and presented in the paper.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 960-963
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoelectron Spectroscopy of II-VI Semiconductor Heterostructures
Autorzy:
Wörz, M.
Hampel, M.
Flierl, R.
Gebhardt, W.
Powiązania:
https://bibliotekanauki.pl/articles/1952740.pdf
Data publikacji:
1996-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Jv
Opis:
We are growing ZnSe, ZnS and CdSe layers epitaxially on GaAs(001) substrates by atomic layer epitaxy and molecular beam epitaxy. The substrates are prepared by a H-plasma method in order to obtain a sharp interface between substrate and layer. The quality of our samples is controlled by reflection high energy diffraction and X-ray diffraction. Furthermore, the samples are characterized in situ by photoelectron spectroscopy. We observe resonant Zn 3d$\text{}^{8}$ and Cd 4d$\text{}^{8}$ satellites, which are used to check the layer quality. As a result, the valence band offsets of CdSe/ZnSe and ZnSe/CdSe were obtained. The values are ΔE$\text{}_{v}$(ZnSe/CdSe) = -(0.13 ± 0.07) eV and ΔE$\text{}_{v}$(CdSe/ZnSe) = -(0.13 ± 0.07) eV, which confirm the commutativity rule.
Źródło:
Acta Physica Polonica A; 1996, 90, 5; 1113-1117
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nanostructured W-Cu Electrical Contact Materials Processed by Hot Isostatic Pressing
Autorzy:
Tsakiris, V.
Lungu, M.
Enescu, E.
Pavelescu, D.
Dumitrescu, Gh.
Radulian, A.
Mocioi, N.
Powiązania:
https://bibliotekanauki.pl/articles/1194884.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Ni
81.05.Mh
79.60.Jv
81.20.Ev
Opis:
Nanostructured W-Cu-Ni electrical contact materials to be used in low voltage vacuum switching contactors for nominal currents up to 630 A were developed successfully by hot isostatic pressing. W-Cu-Ni composite powder mixtures with copper content of 20 to 40 wt% and 1 wt% Ni were mechanically alloyed in Ar atmosphere by high-energy ball milling with a ratio of milling steel balls: powders mixtures of 8:1 and rotation speed of 400 rpm for 10 and 20 h. The effect of mechanical alloying on the sintering response of composite compacts was investigated. Also, the sintered contacts were characterized from the point of view of physical, microstructural, mechanical, and functional properties. The nanostructured electrical contacts presented very good sinterability and homogeneous structures with a maximum compactity degree of about 89%. The best W-Cu-Ni compositions with relative density of about 80%, chopping currents lower than 5 A, copper content lower than 40% as W-20Cu-1Ni (10 h of mechanical alloying and 20 h of mechanical alloying) and W-30%Cu-Ni (10 h of mechanical alloying) were selected to be used in vacuum contactors.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 348-352
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Layered Semiconductors and Related Systems
Autorzy:
Starnberg, H.
Powiązania:
https://bibliotekanauki.pl/articles/2027481.pdf
Data publikacji:
2001-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Nr
71.20.Tx
79.60.Bm
79.60.Jv
Opis:
The general properties of the layered transition metal dichalcogenides and the possibility to modify these materials by intercalation are reviewed. Examples are given of experimental results obtained by using angle-resolved photoelectron spectroscopy and very-low-energy electron diffraction. The possibility to use layered semiconductors as model systems in studies of e.g. Schottky barriers and surface photovoltage is exemplified by the Rb/WSe$\text{}_{2}$ system. Attention is also paid to the use of van der Waals epitaxy in interface studies, and its possible practical applications. The potential of layered semiconductors like WSe$\text{}_{2}$ in solar cell applications is also mentioned.
Źródło:
Acta Physica Polonica A; 2001, 100, 3; 301-318
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infrared Detectors for the Future
Autorzy:
Rogalski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1807754.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.79.Pw
07.57.Kp
73.21.Cd
78.67.Pt
79.60.Jv
Opis:
In the paper, fundamental and technological issues associated with the development and exploitation of the most advanced infrared detector technologies are discussed. In this class of detectors both photon and thermal detectors are considered. Special attention is directed to HgCdTe ternary alloys on silicon, type-II superlattices, uncooled thermal bolometers, and novel uncooled micromechanical cantilever detectors. Despite serious competition from alternative technologies and slower progress than expected, HgCdTe is unlikely to be seriously challenged for high-performance applications, applications requiring multispectral capability and fast response. However, the nonuniformity is a serious problem in the case of LWIR and VLWIR HgCdTe detectors. In this context, it is predicted that type-II superlattice system seems to be an alternative to HgCdTe in long wavelength spectral region. In well established uncooled imaging, $VO_x$ microbolometer arrays are clearly the most used technology. In spite of successful commercialization of uncooled microbolometers, the infrared community is still searching for a platform for thermal imagers that combine affordability, convenience of operation, and excellent performance. Recent advances in microelectromechanical systems have led to the development of uncooled IR detectors operating as micromechanical thermal detectors. Between them the most important are biomaterial microcantilevers.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 389-406
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of TDMAAs Acceptor Precursor on Performance Improvement of HgCdTe Photodiodes
Autorzy:
Madejczyk, P.
Gawron, W.
Piotrowski, A.
Kłos, K.
Rutkowski, J.
Rogalski, A.
Powiązania:
https://bibliotekanauki.pl/articles/1506804.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.79.Pw
07.57.Kp
73.21.Cd
78.67.Pt
79.60.Jv
Opis:
One of the key factor which determine HgCdTe photodiode quality is acceptor doping efficiency. This paper presents significant progress made over the past three years in development of acceptor doping technology in metalorganic chemical vapour deposition HgCdTe photovoltaic detectors. High acceptor doping is required for $P^{+}$-contact layers, whereas low doping is necessary for p-type absorbing base layer. Previously, $AsH_3$ precursor was used as an acceptor dopant. This precursor is partially incorporated as electrically neutral As-H pairs, which are likely to be recombination centres in HgCdTe and in consequence influence on the carriers lifetime lowering. Substituting of $AsH_3$ by TDMAAs resulted in higher carrier lifetimes and thereby about one order of magnitude higher $R_0A$ product of HgCdTe photodiodes in temperatures close to 230 K.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1199-1204
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Ceramic Nanoparticles on Thermal Stability of Ultra Fine Grained Copper
Autorzy:
Čížek, J.
Procházka, I.
Cieslar, M.
Islamgaliev, R.
Kulyasova, O.
Powiązania:
https://bibliotekanauki.pl/articles/1812477.pdf
Data publikacji:
2008-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.70.Bj
79.60.Jv
Opis:
A detailed study of the bulk ultra fine grained pure copper and copper with $Al_2O_3$ particles was carried out in the present work. The specimens were prepared by the high-pressure torsion and their microstructure was investigated by positron lifetime spectroscopy combined with transmission electron microscopy and microhardness tests. Defects in the as-deformed materials were characterized and the thermal stability of the ultra fine grained microstructure was subsequently examined in annealing experiments. An addition of $Al_2O_3$ nanoparticles was found to improve significantly the thermal stability of the ultra fine grained structure, the optimum content of $Al_2O_3$ being ≈0.5 wt.%.
Źródło:
Acta Physica Polonica A; 2008, 113, 5; 1285-1292
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Growth of β-$Ga_2O_3$ Nanorods and Photoluminescence Properties
Autorzy:
Zhang,, S.
Zhuang, H.
Xue, C.
Li, B.
Shen, J.
Wang, D.
Powiązania:
https://bibliotekanauki.pl/articles/1814023.pdf
Data publikacji:
2007-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
68.65.-k
79.60.Jv
81.15.Cd
Opis:
β-$Ga_2O_3$ nanorods were successfully fabricated through annealing $Ga_2O_3$/Mo films deposited on the Si (111) substrate by radio frequency magnetron sputtering technique. The morphology and structure of the as-synthesized nanorods were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and energy dispersive X-rays spectroscopy. The results show that the formed nanorods are single-crystalline $Ga_2O_3$ with monoclinic structure. The diameters of nanorods are 200 nm and lengths typically up to several micrometers. A photoluminescence spectrum at room temperature under excitation at 325 nm exhibits two strong blue-light peaks located at about 413.0 nm and 437.5 nm, attributed to the recombination of bound electron-hole exciton in β-$Ga_2O_3$ single crystal. The growth process of the β-$Ga_2O_3$ nanorods is probably dominated by conventional vapor-solid mechanism.
Źródło:
Acta Physica Polonica A; 2007, 112, 6; 1195-1201
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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