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Wyszukujesz frazę "61.72.uj" wg kryterium: Temat


Tytuł:
Characterization of Non-Polar ZnO Layers with Positron Annihilation Spectroscopy
Autorzy:
Zubiaga, A.
Tuomisto, F.
Zúñiga-Pérez, J.
Muñoz-San José, V.
Powiązania:
https://bibliotekanauki.pl/articles/1811964.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uj
68.55.Ln
68.37.-d
78.70.Bj
Opis:
We applied positron annihilation spectroscopy to study the effect of growth polarity on the vacancy defects in ZnO grown by metal-organic vapor phase deposition on sapphire. Both c-plane and a-plane ZnO layers were measured, and Zn vacancies were identified as the dominant defects detected by positrons. The results are qualitatively similar to those of earlier experiments in GaN. The Zn vacancy concentration decreases in c-plane ZnO by almost one order of magnitude (from high $10^{17} cm^{-3}$ to low $10^{17} cm^{-3}$) when the layer thickness is increased from 0.5 to 2 μm. Interestingly, in a-plane ZnO the Zn vacancy concentration is constant at a level of about $2×10^{17} cm^{-3}$ in all the samples with thicknesses varying from 0.6 to 2.4 μm. The anisotropy of the Doppler broadening of the annihilation radiation parallel and perpendicular to the hexagonal c-axis was also measured.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1257-1264
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analysis of Interaction of Surfactant Molecules with Si(hkl) Planes on the Basis of Anisotropic Etching in Alkaline Solutions
Autorzy:
Zubel, I.
Kramkowska, M.
Powiązania:
https://bibliotekanauki.pl/articles/1807532.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.30.Hn
61.72.uj
64.70.kg
Opis:
In the paper, measurements of surface tension of solutions used for silicon etching and results of etching in the solutions are presented. Based on the obtained results, the analysis of interactions of surfactants with differently oriented silicon planes has been carried out.
Źródło:
Acta Physica Polonica A; 2009, 116, S; S-105-S-107
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anharmonicity Effects in Nanocrystals Studied by Raman Scattering Spectroscopy
Autorzy:
Dohčević-Mitrović, Z.
Popović, Z.
Šćepanović, M.
Powiązania:
https://bibliotekanauki.pl/articles/1807800.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.22.-m
78.67.Bf
78.30.-j
61.72.uj
Opis:
Phonon-phonon interactions were investigated in various nanocrystalline powders like anatase $TiO_{2-δ}$, pure $CeO_{2-δ}$ and ceria doped with Nd(Gd) analyzing temperature dependent Raman spectra of these systems. Phonon confinement model based on size, inhomogeneous strain and anharmonic effects was used to properly describe the evident changes present in the Raman spectra of pure and doped ceria nanocrystalline samples. In small particles of pure and doped ceria nanocrystals, when size effects have minor impact on Raman modes, four phonon anharmonic processes prevail under the three-phonon ones. When nanopowdered particles are grown enough size effects provoke changes of the anharmonic interactions when three-phonon coupling prevails over the four-phonon anharmonic processes. In nanocrystalline anatase $TiO_2$ evident blueshift of the most prominent $E_g$ Raman mode probably originates from dominant four-phonon anharmonic interactions.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 36-41
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of $Fe^{2+} (Fe^{3+})$ Doping on Structural Properties οf $CeO_2$ Nanocrystals
Autorzy:
Radović, M.
Dohčević-Mitrović, Z.
Paunović, N.
Šćepanović, M.
Matović, B.
Popović, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1807838.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uj
78.30.-j
75.50.Tt
Opis:
We have measured the Raman scattering and magnetization of pure and $Fe^{2+}(Fe^{3+})$ doped $CeO_2$ nanopowders at room temperature. The Raman scattering spectra revealed the existence of $CeO_2$ fluorite cubic structure for all investigated samples. The Raman active mode at about 600 $cm^{-1}$, seen in all samples, can be ascribed to the $CeO_2$ intrinsic oxygen vacancies. Additional Raman modes at 720 $cm^{-1}$, 1320 $cm^{-1}$ and 1600 $cm^{-1}$, which appear in the spectra of doped samples, can be assigned to maghemite $(γ-Fe_2O_3)$ cation deficient structure, to $2ω_{LO}$ IR-allowed overtone and two magnon structure, respectively. This implies that our powders are composed of mixed valence states and have defective structure. Presence of oxygen defect states and magnetic ions can be responsible for the observed ferromagnetism at room temperature in both pure and Fe doped samples.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 84-87
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Free Carrier Scattering in Metallic n-GaAs in the Presence of Static Lattice Distortions Due to a Partial Chemical Order of Impurities
Autorzy:
Słupiński, T.
Molas, M.
Papierska, J.
Powiązania:
https://bibliotekanauki.pl/articles/1791426.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.sd
61.72.uj
72.20.-i
Opis:
Simple electric transport versus T = 20-400 K in metallic n-GaAs annealed single crystals with Te impurity concentration ∿(0.4-1.7) × $10^{19} cm^{-3}$, which is above the equilibrium doping limit, is reported and compared with modern theory of electron mobility in degenerated n-GaAs by Szmyd, Hanna, Majerfeld. An overcome of the equilibrium doping limit in annealed n-GaAs is manifested by a lowered electrical activation of Te donors and by an onset of ≈ 0.1-1 μm regions of local strain in the crystal lattice known from high resolution X-ray studies. These preliminary results of transport show that the electron mobility μ(T) measured for n-GaAs with local strains is not consistent with predictions of Szmyd et al. model for any degree of compensation assumed. This surprising result indicates that electric transport in materials above the equilibrium doping limit is not well understood assuming the scattering by ionized impurities. The nature of defects responsible for an observed strong reduction of free carrier concentration (here ≈ 80%) in annealed heavily doped n-GaAs seems not to be related with electrical compensation. We point here at the possible role of effects of free carrier scattering due to static lattice distortions (local strains) related to a chemical aggregation of impurity atoms. We also notice that transport in metallic n-GaAs with local strains shows features similar to a weak localization $σ_{xx}$ ∝ log T.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 979-982
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Near IR Refractive Index for GaInN Heavily Doped with Silicon
Autorzy:
Cywiński, G.
Kudrawiec, R.
Rzodkiewicz, W.
Kryśko, M.
Litwin-Staszewska, E.
Misiewicz, J.
Skierbiszewski, C.
Powiązania:
https://bibliotekanauki.pl/articles/1791356.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uj
78.66.Fd
81.15.Hi
68.55.-a
78.20.-e
Opis:
The authors report on growth and results of infrared measurements of GaInN heavily doped with silicon. The lattice matched to GaN epitaxial layer of $Ga_{0.998}In_{0.002}N:Si$ has been grown in plasma assisted molecular beam epitaxy in the metal rich conditions. The room temperature Hall concentration and mobility of electrons are 2× $10^{20} cm^{-3}$ and 67 $cm^{2}$/(Vs), respectively. The refractive index has been determined by variable angle spectroscopic ellipsometry. The refractive index exhibited a significant reduction of its value (from 2.25 to 2 at 1.55 μm) at near IR range where are the main interests of potential applications for nitride based intersubband devices. Reported here values of refractive indices at 1.55 and 1.3 μm are appropriate for fabrication of cladding layers with the required contrast to GaN for intersubband devices. The observed drop of refractive index is attributed to the carrier-induced plasma edge effect, which has been directly observed in reflectance spectrum.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 936-938
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Influence of Ion Implantation on the Optical Parameters - Refraction and Extinction Coefficients οf the Oxygen-Enriched Layers Covering GaAs Implanted with Indium Ions
Autorzy:
Rzodkiewicz, W.
Kulik, M.
Pyszniak, K.
Kobzev, A.
Powiązania:
https://bibliotekanauki.pl/articles/1807545.pdf
Data publikacji:
2009-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uj
78.66.Qn
82.80.Yc
Opis:
The semi-isolating GaAs (100) samples irradiated with fluence 3 × $10^{15}$ ions/$cm^{2}$ of $In^{+}$ ions were characterized by using the methods: Rutherford backscattering spectroscopy, nuclear reaction analysis and ellipsometric spectroscopy. The values of the thicknesses layers enriched with oxygen and the implanted were determined by the methods of nuclear reaction analysis and Rutherford backscattering spectroscopy. Multilayer models were applied for determination of the optical constants (refraction and extinctions coefficients) of investigated samples. The thickness of native oxide covering the surface of implanted GaAs and refraction coefficients were increased after implantation with indium. The spectrum of extinction indexes as a function of light wavelength has two bands near the light wavelengths 400 nm and 480 nm. The observed effects can be interpreted as formation of local oxides of In and InAs precipitates or ternary alloys in enriched with oxygen layers at the surfaces of implanted GaAs.
Źródło:
Acta Physica Polonica A; 2009, 116, S; S-129-S-132
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of Shallow Dislocations on 4H-SiC Substrate by Etching Method
Autorzy:
Ishikawa, Y.
Yao, Y.
Sato, K.
Sugawara, Y.
Danno, K.
Suzuki, H.
Bessho, T.
Kawai, Y.
Shibata, N.
Powiązania:
https://bibliotekanauki.pl/articles/1492539.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uj
81.65.Cf
68.37.Lp
Opis:
Correlation between dislocation types in epitaxial 4H-SiC and etch pit types on the 4H-SiC wafer surface were investigated by etch pit method and transmission electron microscope. Shallow dislocation on the wafer was found to form round pit without core. The shallow dislocation was estimated half-loop type in wafer and this estimation explains that step-flow growth converts half-loop dislocation into complex dislocation composed by threading dislocation and basal plane dislocation.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-025-A-027
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Jump Mechanism of Electric Charge Transfer in Gallium Arsenide Exposed to Polyenergy Implantation with $H^{+}$ Ions
Autorzy:
Żukowski, P.
Węgierek, P.
Billewicz, P.
Kołtunowicz, T.
Komarov, F.
Powiązania:
https://bibliotekanauki.pl/articles/1504001.pdf
Data publikacji:
2011-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uj
61.72.Cc
72.80.Ey
Opis:
The article presents the experimental results on electric conductivity investigations of gallium arsenide, exposed to polyenergy implantations with $H^{+}$ ions, depending on alternating current frequency (50 Hz ÷ 5 MHz), testing temperature (liquid nitrogen temperature ÷ 373 K) and the temperature of 15 min isochronous annealing (293 ÷ 663 K). It has been found that the obtained dependences σ ($T_{p},$ f) result from a jump mechanism of electric charge transfer between the radiation defects that form in the process of ion implantation. Correlations between annealing of various types of radiation defects and conductivity characteristics σ ($T_{p}$, f) have also been discussed.
Źródło:
Acta Physica Polonica A; 2011, 120, 1; 125-128
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Jump Mechanism of Electric Conduction in n-Type Silicon Implanted with $Ne^{++}$ Neon Ions
Autorzy:
Węgierek, P.
Billewicz, P.
Powiązania:
https://bibliotekanauki.pl/articles/1504000.pdf
Data publikacji:
2011-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.uj
61.72.Cc
72.80.Ey
Opis:
The article presents the results of research on alternating-current electrical conduction in phosphorus-doped silicon, strongly defected by the implantation of $Ne^{++}$ neon ions. An analysis of electrical properties recorded at the annealing temperature of $T_{a}$ = 373 K and affected by the changes of testing temperature ranging from 253 K to 368 K as well as frequency from 50 Hz to 5 MHz has been discussed. The obtained results have confirmed the occurrence of two conduction mechanisms in strongly defected semiconductors: the band conduction mechanism that is characteristic of low frequency values and the jump conduction one that corresponds to higher frequencies.
Źródło:
Acta Physica Polonica A; 2011, 120, 1; 122-124
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Plasma Ion Source with an Internal Evaporator
Autorzy:
Turek, M.
Droździel, A.
Pyszniak, K.
Prucnal, S.
Mączka, D.
Powiązania:
https://bibliotekanauki.pl/articles/1504137.pdf
Data publikacji:
2011-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
07.77.Ka
34.80.Dp
61.72.uj
Opis:
A new construction of a hollow cathode ion source equipped with an internal evaporator heated by a spiral cathode filament and arc discharge is presented. The source is especially suitable for production of ions from solids. The proximity of arc discharge region and extraction opening enables production of intense ion beams even for very low discharge current ($I_{a}$ = 1.2 A). The currents of 50 μA $(Al^{+})$ and 70 μA $(Bi^{+})$ were obtained using the extraction voltage of 25 kV. The source is able to work for several tens of hours without maintenance breaks, giving possibility of high dose implantations. The paper presents the detailed description of the ion source as well as its experimental characteristics like dependences of extracted currents and anode voltage on anode and cathode currents.
Źródło:
Acta Physica Polonica A; 2011, 120, 1; 184-187
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Structural and Optical Properties of ZnO Nanowires Doped with Magnesium
Autorzy:
Zhuang, H.
Wang, J.
Liu, H.
Li, J.
Xu, P.
Powiązania:
https://bibliotekanauki.pl/articles/1505046.pdf
Data publikacji:
2011-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.46.Km
61.72.uj
81.15.Gh
78.67.-n
Opis:
ZnO nanowires doped with Mg have been successfully prepared on Au-coated Si (111) substrates using chemical vapor deposition method with a mixture of ZnO, Mg, and activated carbon powders as reactants at 850°C. The structural, compositional, morphological and optical properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, and photoluminescence spectroscopy. The nanowires are single crystalline in nature and preferentially grow up along [0001] direction with the average diameter and length of about 60 nm and several hundred micrometers, respectively, thinner and longer than the results of literature using the similar method. Room temperature photoluminescence spectroscopy shows a blueshift from the bulk band gap emission, which can be attributed to Mg doping that were detected by energy dispersive X-ray analysis EDX in the nanowires. Finally, the possible growth mechanism of crystalline ZnO nanowires is discussed briefly.
Źródło:
Acta Physica Polonica A; 2011, 119, 6; 819-823
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies of Magnetoresistance in GaAs:Te Crystals with Structural Disorder at Doping Limit
Autorzy:
Tarkowski, T.
Słupiński, T.
Karpierz, K.
Powiązania:
https://bibliotekanauki.pl/articles/2048144.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.-y
61.72.uj
72.20.My
Opis:
Transverse magnetoresistance was studied in monocrystalline GaAs:Te doped above the equilibrium doping limit and annealed to partially deactivate donor impurities. It is shown that in a sample with partial deactivation of Te impurities, which exhibits structural fluctuations in microscale, both strong positive and some negative magnetoresistances arise, which are difficult to understand within the relaxation time approximation in degenerated homogeneous semiconductor. It is discussed that a consideration of the role of spatial fluctuations (in carrier concentration, conductivity, etc.), e.g. as proposed by Herring, allows for an understanding of positive component of magnetoresistance observed in the sample with a distinct microscopic structural disorder. With the aim to better understand the transport in GaAs:Te, a model material doped above the doping limit, we discuss both positive and negative components of measured magnetoresistance.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 726-728
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deposition and Characterization of CdS, CuS and ZnS Thin Films Deposited by SILAR Method
Autorzy:
Guzeldir, B.
Saglam, M.
Ates, A.
Powiązania:
https://bibliotekanauki.pl/articles/1490738.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.05.-a
61.05.cp
61.72.uj
Opis:
Cadmium sulfide, copper sulfide and zinc sulfide films were grown on Si(111) substrate by successive ionic layer adsorption and reaction method at room temperature. The crystalline structure and morphology of obtained films were characterized by X-ray diffraction, scanning electronic microscope and energy dispersive X-ray analysis methods. The films were polycrystalline and showed preferred orientation. The surface morphology of these films looked relatively smooth and homogeneous in the scanning electron microscope image. The energy dispersive X-ray analysis spectra showed that the expected elements exist in the thin films.
Źródło:
Acta Physica Polonica A; 2012, 121, 1; 33-35
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Growth Conditions and Doping on Physical Properties of Gallium Antimonide Single Crystals
Autorzy:
Mirowska, A.
Orłowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1409657.pdf
Data publikacji:
2012-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Ea
81.10.Fq
81.10.-h
81.10.St
72.80.Ey
71.55.Eq
61.72.uj
Opis:
Gallium antimonide (GaSb) single crystals were grown by modified Czochralski method integrated with in situ synthesis in a flowing atmosphere of pure hydrogen. The influence of charge material purity as well as other technological parameters on GaSb crystals quality was investigated. High purity undoped GaSb single crystals were grown with residual acceptors concentration < 1.4 × $10^{17} cm^{-3}$ and high mobility ≈ 690 $cm^2$/Vs (at 300 K). P-type GaSb crystals were doped with silicon (carrier concentration up to 2 × $10^{19} cm^{-3}$) and with zinc (up to 1 × $10^{19} cm^{-3}$). Tellurium doped n-type GaSb single crystals were obtained with concentration up to 2 × $10^{18} cm^{-3}$. Electrical parameters were investigated by the Hall measurements (300 K and 77 K). Temperature dependent Hall measurements (10 ÷ 300 K) were used to compare the quality of undoped GaSb (obtained from Sb of different purity). Dopant concentration was estimated by glow discharge mass spectroscopy analysis. Axial and radial distribution of carrier concentration were investigated especially for Te-doped crystals (low segregation coefficient of Te in GaSb). Great contribution of compensation and self-compensation mechanisms is shown especially for the beginning part of grown crystals and for low Te-doping level. Radial distribution of physical properties for crystals grown in 〈100〉 direction is not axisymmetrical especially for doped GaSb crystals.
Źródło:
Acta Physica Polonica A; 2012, 122, 6; 1111-1114
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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