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Wyświetlanie 1-26 z 26
Tytuł:
X-Ray Photoelectron Study of Yb-Doped InP
Autorzy:
Iwanowski, R. J.
Sobczak, J. W.
Kaliński, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1963388.pdf
Data publikacji:
1997-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
71.55.Eq
Opis:
X-ray photoelectron spectra of core levels are reported for InP:Yb. Crystalline InP, doped with Yb to a level of 0.5 at.%, was grown by the synthesized solute diffusion method. An analysis of the core-level spectra of the constituent components, i.e. In 3d$\text{}_{5}\text{}_{/}\text{}_{2}$ and P 2p, revealed a minor influence of the surface oxide species, mainly in the phosphate-like form. The spectrum of the Yb 4d core level was also recorded. The energy of the Yb 4d$\text{}_{3}\text{}_{/}\text{}_{2}$ peak was found identical to that in Yb metal, whereas the 4d$\text{}_{5}\text{}_{/}\text{}_{2}$ peak was found to be shifted to higher binding energies. This effect was found comparable to the case of advanced oxidation of Yb thus confirming its high reactivity, even as a bulk dopant. The data give also a rare experimental example of detection of bulk dopant atoms in a semiconductor matrix by X-ray photoelectron spectroscopy at the limit of detectability.
Źródło:
Acta Physica Polonica A; 1997, 91, 4; 809-813
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
X-Ray Photoelectron Spectroscopy and Optical Reflectivity Studies of Si Surfaces Prepared by Chemical Etching
Autorzy:
Iwanowski, R. J.
Sobczak, J. W.
Kowalski, B. J.
Powiązania:
https://bibliotekanauki.pl/articles/1931749.pdf
Data publikacji:
1994-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
78.40.Fy
Opis:
Complementary X-ray photoelectron spectroscopy and optical reflectivity studies of crystalline Si(111) surfaces prepared by two different wet chemical etching processes were performed. These included aqueous HF solution etch or diluted CP-4 bath. Optical reflectivity spectra of Si surfaces, measured in the range 3.7-11 eV, were found strongly dependent on the applied etching process. Analysis of the core level X-ray photoelectron spectroscopy data has shown similarity of the surface structure, irrespectively of the etching procedure. Finally, comparison of optical reflectivity and valence band X-ray photoelectron spectra revealed a qualitative correlation between them indicating dominant influence of the bulk (here, the subsurface region containing polishing-induced defects) in the case studied. This paper is the first one which presents correlations between optical reflectivity and X-ray photoelectron spectroscopy data for Si and thus illustrates a bulk sensitivity of both techniques considered.
Źródło:
Acta Physica Polonica A; 1994, 86, 5; 825-830
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ab Initio Study of Electronic Structure and Magnetic Properties of $Gd(Ni_{1-x}Fe_x)_3$ Alloys
Autorzy:
Deniszczyk, J.
Woźniakowski, A.
Borgieł, W.
Powiązania:
https://bibliotekanauki.pl/articles/1427490.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Be
79.60.Bm
Opis:
We present the ab initio investigations of the electronic and magnetic properties of magnetocaloric $Gd(Ni_{1-x}Fe_x)_3$ alloys. To simulate fractional concentrations the supercell approach was implemented and different configurations of iron atoms were considered. Energetical analysis of site preference and magnetic order was performed. The concentration dependence of the averaged total and local magnetic moments and of the valence band photoemission spectra are presented and discussed in reference to experimental data.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1156-1158
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic Structure of $Sm(Ni_{1-x}Co_{x})_3$ Alloys - XPS and ab initio Study
Autorzy:
Majtyka, A.
Sikora, M.
Blachiński, D.
Chełkowska, G.
Deniszczyk, J.
Powiązania:
https://bibliotekanauki.pl/articles/1397014.pdf
Data publikacji:
2018-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Be
79.60.Bm
Opis:
The band structure investigations for $Sm(Ni_{1-x}Co_{x})_3$ alloys by means of X-ray photoelectron spectroscopy (XPS) and an ab initio density functional theory (DFT) calculations are presented. The aim was to determine an effect of Ni/Co substitution on the electronic structure of the alloys. Investigations have shown that the Ni/Co substitution results in a reconstruction of the valence band (VB), especially the intensity near the Fermi level decreases with Co content. An ab initio simulated XPS VB spectra agree qualitatively with experimental ones with the exception of the Sm-4f sub-spectra where the multiplet decomposition is observed. Calculations shown that variation of magnetization in $Sm(Ni_{1-x}Co_{x})_3$ is driven mainly by the Ni/Co-3d and Sm-5d states polarization and increases linearly with rising Co content.
Źródło:
Acta Physica Polonica A; 2018, 133, 3; 673-675
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Angle-Resolved Photoelectron Spectroscopy on CdTe(100) c(2×2)
Autorzy:
Gawlik, K.-U
Brügmann, J.
Harm, S.
Manzke, R.
Skibowski, M.
Kowalski, B.
Orłowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/1929827.pdf
Data publikacji:
1993-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.At
79.60.Bm
Opis:
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$\text{}_{⊥}$, keeping surface related structures at a fixed binding energy position E$\text{}_{b}$. The lack of dispersion for five structures along ΓΔX gives experimental evidence for their surface origin.
Źródło:
Acta Physica Polonica A; 1993, 84, 6; 1093-1099
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Alloying on Magnetism and Electronic Structure of $Gd(In_{1-x}Snₓ)₃$ System - ab initio Study
Autorzy:
Deniszczyk, J.
Bajorek, A.
Chełkowska, G.
Zipper, E.
Powiązania:
https://bibliotekanauki.pl/articles/1386400.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Be
79.60.Bm
Opis:
We present the results of ab initio study of electronic and magnetic properties of $Gd(In_{1-x}Snₓ)₃$ alloys carried out with the use of FP-LAPW method. Our precise ab initio calculations for the first time uniquelly confirmed experimentally based predictions that the ground state magnetic structure of the alloys is antiferromagnetic and that upon the In/Sn substitution the magnetic structure undergo transition, changing the antiferromagnetic ordering from the (π00)-type for the GdSn₃ compound to the (ππ0)-type for the GdIn₃ one. Moreover, calculations gave an explanation of the oscillatory variation of density of states at Fermi level indicated by XPS measurements.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 427-429
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Temperature Dependence of Photofield Emission from Tungsten ⟨001⟩ Direction
Autorzy:
Radoń, T.
Jaskólka, S.
Powiązania:
https://bibliotekanauki.pl/articles/1945415.pdf
Data publikacji:
1996-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
79.70.+q
71.25.Pi
Opis:
The existence of a minimum lying by 0.2 eV above the Fermi level, in the band structure of the ⟨001⟩ direction of tungsten, has been confirmed at temperatures of 600÷800 K of the emitter. With increasing temperature a slight rise of the Fermi level in relation to the band structure has been observed.
Źródło:
Acta Physica Polonica A; 1996, 89, 5-6; 665-668
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Optical Radiation Generated by Partial Discharges on Insulators
Autorzy:
Frącz, P.
Boczar, T.
Borucki, S.
Powiązania:
https://bibliotekanauki.pl/articles/1366318.pdf
Data publikacji:
2014-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
42.79.Pw
52.80.Hc
Opis:
Results of measurements of optical radiation emitted by partial and complete electrical discharges occurring on a bushing insulator model placed in air are presented in the article. Registration was performed using a spectrophotometer, enabling for measurement of optical radiation in the range from 270 to 1700 nm. Detailed characteristics of spectrophotometer are presented in our previous paper. The primary objective of the laboratory tests was to evaluate the impact of supply voltage changes in the range from 0 to 0.99 $U_{b}$ (breakdown voltage) on the intensity and spectral character of the optical radiation emitted by partial discharges generated on the porcelain insulation surface of the bushing insulator. In the scope of studies analyzes of the effects of voltage changes on the obtained spectral waveforms were performed, whereby voltage increase and reduction was examined separately. Additionally, measurements and analyzes carried out included impact estimation of the time period as the voltage was applied to the high-voltage electrodes on the course of optical phenomena related to the generation of partial discharges.
Źródło:
Acta Physica Polonica A; 2014, 125, 6; 1360-1366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Interference Signals Generated by Vibroacoustic Vibrations of Transformer Cores
Autorzy:
Boczar, T.
Borucki, S.
Cichoń, A.
Powiązania:
https://bibliotekanauki.pl/articles/1199078.pdf
Data publikacji:
2014-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
42.79.Pw
52.80.Hc
Opis:
The article deals with the subject matter referring to the interference that may accompany measurements of vibroacoustic signals, generated by electric power transformers, taken by using the acoustic emission method under industrial conditions. Paper concerns measurement and analysis of internal, acoustic type disturbances, including the magnetostrictive vibrations of plate sets within the transformer core, caused by changes in the magnetic flux. Paper presents measurement results of acoustic interfering signals and results of analyses made in the frequency and time-frequency domains. Power spectral density, MUSIC pseudospectra, two- and three-dimensional short time Fourier transform spectrograms, continuous wavelet transform scalograms, discrete wavelet transform, and quantities of energy transferred are included in the paper.
Źródło:
Acta Physica Polonica A; 2014, 125, 6; 1355-1359
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characteristic of Surface Partial Discharges Measured with Ultraviolet Camera
Autorzy:
Frącz, P.
Zmarzły, D.
Boczar, T.
Powiązania:
https://bibliotekanauki.pl/articles/1398747.pdf
Data publikacji:
2015-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.79.Pw
79.60.Bm
52.80.Hc
Opis:
The performed research works consider diagnosis of different models of support and bushing insulators. Insulator systems undergo aging processes, which causes deterioration of the insulating properties. In addition, pollutants that accumulate on the surface of high voltage insulators cause further reduction of the insulation properties. Presence of pollutants and high humidity level cause formation of conductive paths, which acts as a source of partial discharges. Presented results depict optical signals, recorded by ultraviolet camera, which were emitted by surface partial discharges occurring on different insulator models. In particular, the effect of the relative value of camera sensitivity on the number of surface partial discharges counts was evaluated. In addition, analysis of the effect of the surface partial discharges generation time on registered counts number was made. The experiments were performed at a constant voltage of $0.9U_{p}$ and for a distance between the HV electrode and GND equal to 10 cm. The experimental study lasted over a period of 30 min, while the measurement steps were done every minute.
Źródło:
Acta Physica Polonica A; 2015, 127, 3; 715-718
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoemission Study of the Electronic Structure of Semiconducting Compounds
Autorzy:
Fujimori, A.
Okabayashi, J.
Mamiya, K.
Powiązania:
https://bibliotekanauki.pl/articles/2011107.pdf
Data publikacji:
1999-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
71.20.-b
75.50.Pp
Opis:
We review how the electronic structure of semiconducting compounds is revealed by photoemission spectroscopy. Angle-resolved photoemission spectroscopy is used to study band dispersions and the photon-energy dependence of spectral line shapes is utilized to study atomic orbital origins of the electronic states, namely, the partial density of states. We focus on recent development in the studies of diluted magnetic semiconductors as well as other magnetic semiconductors, in which interaction between the relatively localized transition-metal d states and the extended sp band states plays a key role in characterizing their unique magnetic, transport, and optical properties.
Źródło:
Acta Physica Polonica A; 1999, 96, 5; 525-533
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of 4f Level in Samarium-Rich MBE Grown CdSmTe Sample
Autorzy:
Szamota-Sadowska, K.
Gołacki, Z.
Orłowski, B. A.
Boyn, R.
Johnson, R. J.
Powiązania:
https://bibliotekanauki.pl/articles/1991645.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.At
79.60.-i
79.60.Bm
Opis:
Electronic states of 4f samarium ions were investigated by photoemission spectroscopy in samarium-rich CdSmTe sample obtained by MBE. The photon energy of synchrotron radiation allowed to investigate Fano-type resonance and antiresonance. The energy distribution curve spectra were attributed to the Sm 4d-4f transition. The shape of the constant initial states spectra was compared with this one obtained for atomic samarium.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 560-564
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Optical Radiation Generated by Electrical Discharges on Support Insulator
Autorzy:
Frącz, P.
Boczar, T.
Zmarzły, D.
Szczyrba, T.
Powiązania:
https://bibliotekanauki.pl/articles/1399341.pdf
Data publikacji:
2013-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
42.79.Pw
52.80.Hc
Opis:
Subject of the paper concerns determination of the feasibility and indication of the application scope of optical spectroscopy methods in the diagnosis of high-voltage insulators. Results of measurements of optical radiation emitted by partial and complete electrical discharges occurring on a support insulator model placed in air are presented in the paper. Registration was performed using a spectrophotometer, enabling for measurement of optical radiation in the range from 200 to 1800 nm. The primary objective of the laboratory tests was to evaluate the impact of supply voltage changes in the range from 0 to 60 kV on the intensity and spectral character of the optical radiation emitted by electric discharges generated on the porcelain insulation surface of the support insulator. In the scope of studies analyzes of the effects of voltage changes on the obtained spectral wave forms were performed, whereby voltage increase and reduction was examined separately. Additionally, measurements and analyzes carried out included impact estimation of the time period as the voltage was applied to the high-voltage electrodes on the course of optical phenomena related to the generation of electrical discharges.
Źródło:
Acta Physica Polonica A; 2013, 124, 3; 413-416
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic structure of TmPdIn
Autorzy:
Penc, B.
Kurleto, R.
Goraus, J.
Starowicz, P.
Szytuła, A.
Powiązania:
https://bibliotekanauki.pl/articles/1065057.pdf
Data publikacji:
2016-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Eh
71.15.Mb
79.60.Bm
Opis:
Electronic structure of a ternary TmPdIn compound, which crystallizes in the hexagonal ZrNiAl-type structure, was studied by X-ray photoemission spectroscopy and ultraviolet photoemission spectroscopy. Density of states in the valence band was calculated by means of the augmented plane wave/local orbital method based on density functional theory. The results showed that the valence band is formed mainly of Tm 4f and Pd 4d states. In the ultraviolet photoemission spectra one can distinguish Pd 4d maximum and Tm 4f multiplet peaks, which are displaced with respect to those of pure Tm.
Źródło:
Acta Physica Polonica A; 2016, 129, 6; 1184-1186
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Results of Optical Signals Analyses Emitted by Electrical Discharges Recorded with UV Camera
Autorzy:
Frącz, P.
Boczar, T.
Borucki, S.
Cichoń, A.
Zmarzły, D.
Powiązania:
https://bibliotekanauki.pl/articles/1417952.pdf
Data publikacji:
2012-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
42.79.Pw
52.80.Hc
Opis:
In the article results of measurements and analyses of the optical signals emitted by electrical surface partial discharges occurring on bushing and post insulators, recorded with UV camera during tests under laboratory conditions are presented. The carried out research was to determine the effect of the distance between the insulator's electrodes and the voltage value on the number of partial discharges.
Źródło:
Acta Physica Polonica A; 2012, 122, 5; 814-817
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic States of $UNi_2$ from Photoemission Spectroscopy
Autorzy:
Zalecki, R.
Kołodziejczyk, A.
Kim-Ngan, N.
Adamska, A.
Kowalczyk, A.
Toliński, T.
Mihalik, M.
Powiązania:
https://bibliotekanauki.pl/articles/1813761.pdf
Data publikacji:
2008-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
79.60.Bm
71.15.Ap
Opis:
We measured the angle-resolved ultraviolet and X-ray photoemission spectra of $UNi_2$ single crystal. The valence band angle-resolved ultraviolet photoemission spectra were compared to the accessible band structure calculations. For $UNi_2$ the lowest binding energy strong emission at about -0.1 eV comes from U 5f states and overlaps with the Fermi edge. A small feature at -0.6 eV was ascribed also to U 5f electrons with more localised character. The higher-energy two-peak structure at about -1.2 eV and -2.1 eV comes from Ni 3d states. X-ray photoemission spectroscopy shows the standard two-line spin-orbit splitting of the Ni 2p states and of the U 4f states. Some hybridisation of the Ni 3d and U 5f state was observed in the spectra. The pronounced satellites to the Ni 2p and 3p states, associated with the on-site Coulomb repulsion and other electron correlation energies, were observed.
Źródło:
Acta Physica Polonica A; 2008, 113, 1; 407-412
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Resonant Photoemission Study οf 4f Electrons on the Surface οf Semiconductors
Autorzy:
Orłowski, B.
Kowalski, B.
Pietrzyk, M.
Buczko, R.
Powiązania:
https://bibliotekanauki.pl/articles/1811504.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
71.20.Mq
07.85.-m
Opis:
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.
Źródło:
Acta Physica Polonica A; 2008, 114, S; S-103-S-114
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
MBE Growth and Properties of GaMnAs(100) Films
Autorzy:
Sadowski, J.
Domagała, J.
Bąk- Misiuk, J.
Świątek, K.
Kanski, J.
Ilver, L.
Oscarsson, H.
Powiązania:
https://bibliotekanauki.pl/articles/1992165.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Hi
79.60.Bm
71.55.Eq
Opis:
We present here the results of measurements of structural and electronic properties of GaMnAs - a new diluted magnetic semiconductor system. This ternary III-V-Mn compound with the Mn content as high as 7% was obtained for the first time (by means of molecular beam epitaxial growth) by Ohno, Munekata et al. and the studies of its properties are not completed until now. We did the high resolution X-ray diffraction investigations and photoemission measurements of the samples with Mn content varied from about 0.1% up to 5%. The crystalline perfection of the ternary GaMnAs compound is very high - full width at half maximum of GaMnAs (400) Bragg reflections are of order of 50 arcseconds and the layers are fully strained to the GaAs(100) substrate. In photoemission experiments we traced the contribution of Mn 3d states to the band structure of GaMnAs ternary compound.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 509-513
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:
Electronic Structure of $Y_{3}Al_{5}O_{12}:V$ Single Crystals, Comparison with Sintered Ceramics
Autorzy:
Kruczek, M.
Talik, E.
Kusz, J.
Sakowska, H.
Świrkowicz, M.
Węglarz, H.
Powiązania:
https://bibliotekanauki.pl/articles/1810470.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
33.60.+q
33.70.Jg
79.60.-i
79.60.Bm
Opis:
$Y_{3}Al_{5}O_{12}$ (YAG) single crystals doped with vanadium ions $(V^{3+})$ were obtained by the Czochralski method. The X-ray photoelectron spectra of YAG:V annealed in reducing atmospheres: $H_{2}$, vacuum and $H_{2}$ + vacuum are presented and compared with the spectra of the YAG ceramics. The X-ray photoelectron spectra showed that the vanadium dopant concentration in YAG:V crystals is lower than a nominal one. For the "as grown" YAG:2.8at.%V crystal vanadium exists in the mixed valence state. The increase in lattice parameters for the samples annealed in hydrogen was found.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 209-212
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electronic States of Collosal Magnetoresistive Manganites $La_{0.67}Pb_{0.33}Mn_{1-x}Fe_{x}O_{3}$ from Photoemission Spectroscopy
Autorzy:
Kowalik, M.
Zalecki, R.
Kołodziejczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/1538821.pdf
Data publikacji:
2010-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Lp
79.60.Bm
71.15.Ap
74.20.Mn
Opis:
The electron photoemission spectra of valence bands and core-level states of manganese perovskite $La_{0.67}Pb_{0.33}(Mn_{1-x}Fe_{x})O_{3}$ with x = 0, 0.01, 0.03, 0.06, 0.10 and 0.15 were measured by the X-ray and Ultraviolet Photoemission Spectroscopy (XPS and UPS) below and above the metal-insulator transition. From analysis of the Mn 2p core-level spectra the ratio $Mn^{3+}//Mn^{4+}$ was calculated as a function of the iron content. Comparison of the valence band spectrum with band structure calculations and with the high-resolution spectra measured at synchrotron radiation for Ca-, Ba- and Ce- substituted manganites revealed the strong hybridisation of Mn 3d and of O 2p states between -3 eV and -7 eV, and no estimated oxygen states between 0 eV and -2 eV where the Mn-3d states play a predominant role. The composition dependent insulating energy gaps were measured at room temperature. Reasons for the behaviour were discussed taking into account previous analysis of XPS/UPS spectra of other manganese perovskites.
Źródło:
Acta Physica Polonica A; 2010, 117, 2; 277-280
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Bimetallic Systems with UPS and PAX: Gold on Platinum and Palladium Surfaces
Autorzy:
Moors, M.
Kobiela, T.
Krupski, A.
Becker, C.
Wandelt, K.
Powiązania:
https://bibliotekanauki.pl/articles/1811505.pdf
Data publikacji:
2008-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.Bm
73.61.At
71.20.Be
71.20.Eh
71.20.Gj
Opis:
In the present study the thermal behavior of ultrathin Au films deposited on different noble metal single crystal surfaces was studied by means of ultraviolet photoelectron spectroscopy and photoemission of adsorbed xenon. The primary goal of this work was to demonstrate the power of photoemission of adsorbed xenon as an easy to handle and very surface sensitive technique for the characterization of multi-component systems. All investigated systems, Au-Pt(111), Au-Pd(111) and Au-Pd(110) show a particular dependence of their electronic and structural properties on the annealing temperature. Au multilayer films with a thickness of 3 monolayer prepared at 150 K undergo in all cases a smoothening by annealing up to room temperature. While on Pd this effect is mainly detectable on the topmost atomic layer the ordering process on Pt is also affecting the deeper layers. Further annealing of the Au-Pd system to 450 K and the Au-Pt system to 750 K, respectively, results in the onset of the alloying process at the interface between metal film and substrate. After annealing to 650 and 950 K, respectively, the alloying finally extends to the very surface. The complete loss of Au from the surface can be detected at 1050 K on Pd and at 1150 K on Pt. The orientation of the substrate has only a weak influence, showing up e.g. in additional electronic states of the not alloyed Au-Pd(111) and Au-Pd(111) systems. Adsorption of CO as a probe molecule illustrates the formation of different adsorption sites on the bimetallic systems during the Au diffusion process.
Źródło:
Acta Physica Polonica A; 2008, 114, S; S-77-S-92
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoemission by Polarized X-Rays
Autorzy:
Tilinin, I. S.
Powiązania:
https://bibliotekanauki.pl/articles/1964041.pdf
Data publikacji:
1997-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.80.Bm
72.10.Bg
79.60.-i
Opis:
The angular distribution of photoelectrons excited by X-rays is strongly correlated with the degree and type of polarization of incident photons. The angular and energy spectrum of signal photoelectrons leaving a solid is considerably modified as compared to the differential photoelectric cross-section owing to elastic and inelastic collisions the electrons suffer on their way out of a target. In this report an analytical expression for the angular distribution of photoelectrons escaping from the sample without being scattered inelastically was found in the transport approximation. The dependence of the angular distribution on the parameters characterizing optical orientation and polarization of incident X-rays was studied in detail.
Źródło:
Acta Physica Polonica A; 1997, 91, 5; 887-892
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Angular Distribution of Photoemission from Surfaces of Amorphous Solids
Autorzy:
Jabłoński, A.
Powiązania:
https://bibliotekanauki.pl/articles/1931731.pdf
Data publikacji:
1994-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.80.Bm
72.10.-d
79.60.-i
Opis:
As follows from the formalism of X-ray photoelectron spectroscopy, knowledge of the angular distribution of photoemission is crucial for certain applications of quantitative X-ray photoelectron spectroscopy analysis. In the present work, the experimental data on the relative angular distribution of photoemission from solid materials are reviewed and compared with theoretical predictions. Noticeable discrepancies are usually observed. It has been proved that major part of the observed discrepancies can be ascribed to elastic photoelectron scattering. The commonly used formalism, where the elastic collisions are neglected, may be of insufficient reliability for certain solids, or in certain experimental geometries. This formalism can be easily extended to account for elastic photoelectron collisions by introducing two correction factors, Q$\text{}_{X}$ and β$\text{}_{eff}$. The second parameter, called the effective asymmetry parameter, describes the observed decrease in anisotropy of photoemission. Determination of the correction factors requires a reliable theory describing elastic electron scattering in the solid. A need arises for accurate differential and total elastic electron scattering cross-sections pertinent to kinetic energies of considered photoelectrons or the Auger electrons. The increasingly important role of electron transport in surface analysis has stimulated an effort to construct a complete database containing the differential and total atomic elastic scattering cross-sections.
Źródło:
Acta Physica Polonica A; 1994, 86, 5; 787-798
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mean Escape Depth of Signal Photoelectrons from Amorphous and Polycrystalline Solids
Autorzy:
Tilinin, I. S.
Jabłoński, A.
Lesiak-Orłowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1931766.pdf
Data publikacji:
1994-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.80.Bm
72.10.Bg
79.60.-i
Opis:
Escape depth of photoelectrons leaving a target without being scattered inelastically was submitted to extensive theoretical analysis. Dependence of the mean escape depth on the X-ray angle of incidence and the electron initial angular distribution inside the sample was considered. The Monte Carlo algorithm was developed basing on a differential elastic scattering cross-section calculated within the partial-wave expansion method and a realistic electron-atom interaction potential. The mean escape depth was evaluated by means of the depth distribution function found analytically by solving a kinetic equation and by the Monte Carlo technique. The agreement between the results obtained from two methods is excellent. Elastic scattering was found to reduce considerably the escape depth. This reduction may reach up to 25% in the case of heavy elements in the practical X-ray photoelectron spectroscopy analysis. It was shown that the mean escape depth expressed in units of the electron transport mean free path is a universal function of the ratio of the inelastic to the transport mean free paths, the asymmetry parameter and the X-ray angle of incidence. A simple explicit expression for this function is proposed.
Źródło:
Acta Physica Polonica A; 1994, 86, 5; 845-852
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Signal Photoelectron Yield Dependence on the X-Ray Angle of Incidence
Autorzy:
Tilinin, I. S.
Jabłoński, A.
Lesiak-Orłowska, B.
Powiązania:
https://bibliotekanauki.pl/articles/1931768.pdf
Data publikacji:
1994-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.80.Bm
72.10.Bg
79.60.-i
Opis:
The photoelectron emission from solids irradiated by X-rays was described by the analytical theory of electron transport and simulated by the Monte Carlo technique. The medium energy electron transport problem is treated by means of a Boltzmann type kinetic equation satisfying appropriate boundary conditions. The solution of the transport equation was obtained in the transport approximation based on the generalized radiative field similarity principle. Simple and reliable formalism was derived for both the differential and the total photoelectron yields. The dependence of the photoelectron yield on the X-ray incidence angle and the "flattening" effect of multiple elastic scattering on the angular distribution of electrons leaving the target are analysed in detail. The photoelectron yields and angular distributions calculated by the Monte Carlo algorithm, based on a realistic differential elastic scattering cross-section, are in good agreement with the results found from analytical theory. It is shown that main characteristics of the photoelectron emission are determined primarily by two parameters: the inelastic and the transport mean free paths.
Źródło:
Acta Physica Polonica A; 1994, 86, 5; 853-859
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
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