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Tytuł:
Electrical Properties of Lead Phthalocyanine Films
Autorzy:
Abd El-Rehim, N.
El-Samahy, A.
Powiązania:
https://bibliotekanauki.pl/articles/1946191.pdf
Data publikacji:
1996-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
Opis:
Current density-voltage characteristics have been obtained from thin films of lead phthalocyanine particles dispersed in a polymer binder when sandwiched between ohmic gold and blocking aluminium electrodes. At low voltages, the current in the forward direction shows Schottky diode behaviour. The diode parameters are evaluated using the model of Cheung and Cheung. Barrier heights and widths are determined as a function of applied voltage. A number of parameters is evaluated on the basis of the theory of space-charge-limited conduction, and the following values are obtained: p$\text{}_{0}$ = 8.5 × 10$\text{}^{18}$ m$\text{}^{-3}$, concentration of the traps per unit energy range at the valence band P$\text{}_{0}$ ≈ 2.5 × 10$\text{}^{44}$ J$\text{}^{-1}$m$\text{}^{-3}$, temperature parameter of trapping distribution T$\text{}_{c}$ ≈ 500 K and total trapping concentration, N$\text{}_{t}$ ≈ 1.7 × 10$\text{}^{24}$ m$\text{}^{-3}$.
Źródło:
Acta Physica Polonica A; 1996, 90, 3; 557-564
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy Relaxation in Two-Dimensional Electron GaS in InGaAs/InP via Electron-Acoustic Phonon Interaction
Autorzy:
Kreshchuk, A. M.
Novikov, S. V.
Savel'ev, I. G.
Polyanskaya, T. A.
Pődör, B.
Reményi, G.
Kovács, Gy.
Powiązania:
https://bibliotekanauki.pl/articles/1991650.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
Opis:
The energy relaxation in two-dimensional electron gas in In$\text{}_{0.53}$Ga$\text{}_{0.47}$As/InP has been studied in a wide range of electron temperatures (from 0.1 to 10 K). The energy loss rate of electrons is controlled by the interaction of electrons with the piezoelectric potential of acoustic phonons. The value of the piezoelectric constant for InGaAs lattice-matched to InP is deduced from theoretical fits of the experimental data: h$\text{}_{14}$=(1.1±0.1)×10$\text{}^{7}$ V/cm. Available data for the piezoelectric constant of In$\text{}_{x}$Ga$\text{}_{1-x}$As are discussed in the light of the results of this work.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 415-420
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Transport Properties in 2,6-Diamino Anthraquinone
Autorzy:
Khalil, S. M.
Darwish, S.
Powiązania:
https://bibliotekanauki.pl/articles/1931351.pdf
Data publikacji:
1994-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
Opis:
Current density-voltage characteristics were obtained from 2,6-diamino anthraquinone samples using ohmic aluminium electrodes. Results showed that at low voltage the conduction process was ohmic, while at high voltage space-charge-limited conduction controlled by a single dominant trap level was presented. Thickness dependence measurements proved that the trapping sites were located at a discrete energy level. The transition voltage, V, between ohmic and space-charge-limited conduction was approximately proportional to the square of the sample thickness and was found to be temperature independent. The temperature dependence of ohmic and space-charge-limited current densities have been investigated. The results were interpreted in terms of extrinsic nature of ohmic conduction. Traps with density ≈ 2 × 10$\text{}^{24}$ m$\text{}^{-3}$ located at 0.50 ± 0.03 eV below the conduction band edge have been observed.
Źródło:
Acta Physica Polonica A; 1994, 85, 6; 953-958
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Transitional Metals Doping on Conductivity of Collagen Lyophilisate and Elastin
Autorzy:
Gauza, M.
Kubisz, L.
Powiązania:
https://bibliotekanauki.pl/articles/1490449.pdf
Data publikacji:
2012-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
72.80.Le
Opis:
Knowing that conductivity is a temperature function σ = f(T) allows us to estimate the thermal stability of collagen preparations from fish skin. Measurements can provide information, which is crucial for technologies applying this type of collagen. Conductivity σ measurements were performed in a constant electric field E = 1 kV/m, in the temperature range of 290-480 K. White collagen lyophilisate was used as control material. It contained neither elastin nor melanin dopants nor non-organic dopants such as gold, copper, silver or zinc. Gold, copper, silver and zinc belong to the group of transitional metals and they have intermediate properties of both alkaline metals and metals in the p block of the periodic table. The common feature of most of these elements is their ability to form coordination complexes of intense color. In the measured materials peaks were found in the temperature range of 303-323 K. Peak temperature and its shape depend on the type of material. In the case of nano-gold doping a drop in peak temperature and a decrease in conductivity were observed. The measured materials are characterized by lower thermal resistance than bovine collagen. Nevertheless, thermal stability of fish skin collagen is high enough for fish skin collagen to replace bovine collagen. The measurement results obtained for white collagen and white collagen with $Zn^{2+}$ may indicate better bonding of free water. The presence of nano-silver and nano-copper as doping agents in graphite collagen may lead to a decrease in hygroscopy of the material and, as a result, may increase its resistance to bacteria.
Źródło:
Acta Physica Polonica A; 2012, 121, 1A; A-065-A-067
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical Conductivity of Fish Skin Collagen in the Temperature Range 290-380 K
Autorzy:
Gauza, M.
Kubisz, L.
Powiązania:
https://bibliotekanauki.pl/articles/1537417.pdf
Data publikacji:
2010-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
72.80.Le
Opis:
Collagen is the major biopolymer of a living organism, which physical properties depend on water content. The observed transmission of spongiform encephalophaties (BSE) to humans resulted in the development of new sources of collagen. Fish skin seems to be one of such safe sources of collagen. Measurements of electrical conductivity as a function of temperature provides information, among other things, on the water release process. Experiment was carried out for fish skin (FSC) collagen (type I) and bovine Achilles tendon collagen (type I). Each sample was heated two times. Current-voltage characteristic was determined for FSC collagen to determine the range, within which the relation is linear. The primary differences appeared to be in electric conductivity, which was higher for FSC collagen than for BAT collagen. Electric conductivity varied from 10^{-6} S/m to 10^{-10} S/m depending on material and temperature. The process of free and bound water release was manifested as a peak on electrical conductivity-temperature curve between 320-350 K. The activation energy of the charge conduction process, determined on the basis of the Arrhenius plot, was material dependent and considerably higher for FSC collagen.
Źródło:
Acta Physica Polonica A; 2010, 118, 1; 54-57
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical and Dielectric Properties of Amorphous Ge$\text{}_{1}$Se$\text{}_{1.35}$TL$\text{}_{0.1}$ Films
Autorzy:
Abdel-Aziz, M. M.
Afifi, M. A.
Labib, H. H.
El-Metwally, E. G.
Powiązania:
https://bibliotekanauki.pl/articles/2014346.pdf
Data publikacji:
2000-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ng
72.20.-i
Opis:
The temperature dependence of the DC and AC electrical conductivity were measured for Ge$\text{}_{1}$Se$\text{}_{1.35}$Tl$\text{}_{0.1}$ films. The value of DC electrical conduction energy ΔE$\text{}_{σ}$ does not depend on film thickness in the investigated range with mean value of 0.72eV. The AC conductivity σ$\text{}_{AC}$ is related to frequency by the expression σ$\text{}_{AC}$=Aω$\text{}^{S}$, where S is the frequency exponent which decreases linearly with increasing temperature. This can be explained in terms of the pair (bipolaron) correlated barrier hopping model suggested by Elliott. The frequency and temperature dependence of real and imaginary parts of the dielectric constant were studied for Ge$\text{}_{1}$Se$\text{}_{1.35}$Tl$\text{}_{0.1}$ films. The dielectric constant (real part) and the dielectric loss (imaginary part) increase with increasing temperature and decrease with increasing frequency in the investigated range of frequency and temperature. The maximum barrier height W$\text{}_{M}$ can be calculated according to the Giuntini equation at different temperatures. The obtained value of W$\text{}_{M}$ is in good agreement with the theory of hopping of charge carriers over a potential barrier as suggested by Elliott in case of chalcogenide glasses.
Źródło:
Acta Physica Polonica A; 2000, 98, 4; 393-399
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Oxygen Impurities on Electrical Properties of Fullerene C$\text{}_{60}$
Autorzy:
Rabenau, T.
Roth, S.
Kremer, R. K.
Powiązania:
https://bibliotekanauki.pl/articles/1933397.pdf
Data publikacji:
1995-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
72.80.Le
72.20.-i
Opis:
We present high temperature dc, ac and contactless microwave conductivity results on solid-state C$\text{}_{60}$ (films and crystals) from room temperature up to 850 K. Heating pristine samples, which were exposed to the ambient atmosphere, under dynamic vacuum at first leads to a reduction of the electrical resistance and finally, above ≈700 K, to an increase in the resistance. The decrease is ascribed to oxygen desorption and the increase to the chemical reactivity of residual chemisorbed oxygen with the C$\text{}_{60}$ host molecules, respectively. Samples, annealed above 800 K, display a reversible temperature dependence of the resistance. The high temperature regime of their resistance exhibits an activated behaviour with an universal activation energy of 2E$\text{}_{a}$ = 1.85 ± 0.04 eV for crystals and films, which is identical to the HOMO-LUMO splitting of the C$\text{}_{60}$-molecules.
Źródło:
Acta Physica Polonica A; 1995, 87, 4-5; 881-884
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photovoltaic Effect and Space Charge Limited Current Analysis in $TlGaTe_2$ Crystals
Autorzy:
Qasrawi, A.
Yaseen, T.
Eghbariy, B.
Gasanly, N.
Powiązania:
https://bibliotekanauki.pl/articles/1419787.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
72.20.Ht
72.40.+w
Opis:
Anisotropic space charge limited current density analysis and photovoltaic effect in $TlGaTe_2$ single crystals has been investigated. It is shown that, above 330 K, the crystal exhibits intrinsic and extrinsic type of conductivity along (c-axis) and perpendicular (a-axis) to the crystal's axis, respectively. The current density (J) is found to be space charge limited. It is proportional to the square and three halves power of voltage (V) along the a- and c-axis, respectively. Along the a-axis and at sufficiently low electric field values, the activation energy of the current density is found to depend on the one half power of electric field. At high electric fields, the activation energy is field invariant. This behavior is found to be due to the Pool-Frenkel effect and due to a trap set located at 0.26 eV, respectively. Along the c-axis the crystal is observed to operate under the Child-Langmuir space charge limited regime. $TlGaTe_2$ crystals are found to exhibit photovoltaic properties. The open circuit photovoltage is recorded as a function of illumination intensity at room temperature.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 152-155
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Novel Organic Semiconductor BTQBT with High Conductivity and High Mobility
Autorzy:
Inokuchi, H.
Imaeda, K.
Powiązania:
https://bibliotekanauki.pl/articles/1943958.pdf
Data publikacji:
1995-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
79.60.-i
72.20.-i
Opis:
We have found a novel organic semiconductor, BTQBT, with a high electrical conductivity of about 10$\text{}^{-3}$ S cm$\text{}^{-1}$ and a high Hall mobility of about 3 cm$\text{}^{2}$ V$\text{}^{-1}$s$\text{}^{-1}$ at room temperature. We have also succeeded in measuring the temperature dependence of the Hall mobility. It varies with temperature as Τ$\text{}^{-1.6}$, which agrees with the theoretical Τ$\text{}^{-1.5}$ dependence for the mobility determined by lattice scattering. The characteristic transport property of BTQBT results from strong intermolecular interactions in the crystal, which is convinced by the energy dispersion with a bandwidth of about 0.5 eV from the theoretical and experimental band structures.
Źródło:
Acta Physica Polonica A; 1995, 88, 6; 1161-1170
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:
Intervalley Transfer of Electrons in ZnS-Type Thin Film Electroluminescent Devices
Autorzy:
Zhao, H.
Wang, Y.
Xu, Z.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/2011094.pdf
Data publikacji:
1999-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
78.60.-b
Opis:
Based on the calculation about intervalley scattering rates in ZnS, the intervalley transfer process in ZnS-type thin film electroluminescent devices is investigated through the Monte Carlo simulation. The transient time of intervalley transfer is about 0.2-0.3 ps, it coincides with that of electron average energy. Intervalley distribution shifts to high valleys as the electric field increased. The electron kinetic energy distributions in different valleys are also gained. We propose that high valleys could store energies, which could prolong the decay of the electron average energy as the field was removed. These results could be used as the basic data on the study of electroluminescent process and the citation of valley parameters in analytic models should be carefully considered.
Źródło:
Acta Physica Polonica A; 1999, 96, 3-4; 475-482
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical Band Model in Monte Carlo Simulation of Electric Transport in ZnS Thin Film Electroluminescent Devices
Autorzy:
Zhao, H.
Wang, Y.
Xu, X.
Powiązania:
https://bibliotekanauki.pl/articles/2014087.pdf
Data publikacji:
2000-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.60.-b
72.20.-i
Opis:
In this paper, an analytical band model is introduced in Monte Carlo simulation of electric transport process in thin film electroluminescent devices. The band structure of ZnS calculated from the empirical pseudopotential method is fitted by using polynomials. The density of states and scattering rates are also calculated from these polynomials. Based on these results, the electric transport process in ZnS-type thin film electroluminescent devices is simulated through the Monte Carlo method. By comparison with others, this model is as fast as the nonparabolic model and as accurate as the full band model. Furthermore, the influence of the band model on the simulation results is also investigated. We show that the dispersion relation and density of states are all important in the simulation.
Źródło:
Acta Physica Polonica A; 2000, 98, 1-2; 123-130
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Annealing on the AC Conductivity and the Dielectric Properties of In$\text{}_{2}$Te$\text{}_{3}$ Thin Films
Autorzy:
Afifi, M. A.
Abd El-Wahabb, E.
Bekheet, A. E.
Atyia, H. E.
Powiązania:
https://bibliotekanauki.pl/articles/2014347.pdf
Data publikacji:
2000-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
77.55.+f
72.20.-i
Opis:
In$\text{}_{2}$Te$\text{}_{3}$ thin films were prepared by thermal evaporation technique. The composition of the films is checked by energy dispersive X-ray analysis. X-ray analysis showed that the as-deposited In$\text{}_{2}$Te$\text{}_{3}$ films as well as films annealed at temperatures ≤473K have crystalline structure. The ac conductivity σ$\text{}_{ac}$(ω), the dielectric constant ε$\text{}_{1}$ and the dielectric loss ε$\text{}_{2}$ of In$\text{}_{2}$Te$\text{}_{3}$ films were studied in the temperature range 303-373K and in the frequency range 100Hz-100kHz. The ac conduction activation energy ΔE$\text{}_{σ}$(ω) was found to be 0.065eV for the as-deposited films. The ac conductivity was found to obey the relation σ$\text{}_{ac}$(ω)=Aω$\text{}^{s}$, where s is the frequency exponent. The obtained temperature dependence of s is reasonably interpreted by quantum mechanical tunneling model. Both the dielectric constant ε$\text{}_{1}$ and the dielectric loss ε$\text{}_{2}$ increased with temperature and decreased with frequency in the investigated range. The frequency and temperature dependencies of σ$\text{}_{ac}$(ω), ε$\text{}_{1}$, and ε$\text{}_{2}$ for the annealed samples have the same behavior as that for the as-deposited samples. However, values of σ$\text{}_{ac}$(ω), ε$\text{}_{1}$, and ε$\text{}_{2}$ measured at any frequency and temperature increased with annealing temperature up to 473K. It was found also that ΔE$\text{}_{σ}$(ω) decreased with annealing temperature.
Źródło:
Acta Physica Polonica A; 2000, 98, 4; 401-409
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Energy Spectrum of Single-Hole States in Transition Metal Oxides
Autorzy:
Lehmann-Szweykowska, A.
Wojciechowski, R. J.
Gehring, G. A.
Powiązania:
https://bibliotekanauki.pl/articles/2013222.pdf
Data publikacji:
2000-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.10.Fd
72.20.-i
Opis:
The p-d hybridised single-hole states of the transition-metal-oxygen tetrahedron (TMO$\text{}_{4}$) are collectivised due to the direct p-p hopping between oxygens of different clusters. The lowest-lying energy band is always narrow and fully occupied. The first excited band gets occupied as an effect of valence-uncompensated doping, so it can be almost localised. The possible hole excitations to the two higher energy bands, which are wider, may imply the Mott-like hopping form of charge transport in these systems.
Źródło:
Acta Physica Polonica A; 2000, 97, 3; 563-566
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correlation between the band-gap energy and the electrical conductivity in MPr₂W₂O₁₀ tungstates (where M = Cd, Co, Mn)
Autorzy:
Sawicki, B.
Tomaszewicz, E.
Piątkowska, M.
Groń, T.
Duda, H.
Górny, K.
Powiązania:
https://bibliotekanauki.pl/articles/1160256.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.20.Ci
72.20.-i
72.80.Sk
Opis:
The values of the direct allowed energy gap determined from the UV-vis-NIR measurements and Kubelka-Munk transformation decrease from 3.38 via 2.70 to 2.42 eV for MPr₂W₂O₁₀ in the sequence M = Cd, Co, Mn, while the values of the activation energy increase from 0.11 via 0.44 to 0.47 eV in the same sequence. In other words, the higher the activation energy, the smaller the energy gap. Because the energy gap is typical for insulators, so electron transport phenomena are considered under the Poole-Frenkel effect and small-polaron mechanism.
Źródło:
Acta Physica Polonica A; 2016, 129, 1a; A-94-A-96
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of Deep-Level Defects on Transient Photoconductivity of Semi-Insulating 4H-SiC
Autorzy:
Suproniuk, M.
Kamiński, P.
Kozłowski, R.
Pawłowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1364028.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.40.+w
71.55.-i
72.20.-i
Opis:
A model enabling the equilibrium conductivity and transient photoconductivity of semi-insulating 4H-SiC to be simulated has been demonstrated. Using this model, the simulations of both equilibrium conductivity and transient photoconductivity have been carried out. Both the simulation and experimental results have shown that the evolution of photoconductivity in time after switching on the band-to-band generation of electron-hole pairs is strongly affected by the properties of deep level defects. The results of transient photocurrent measurements confirm the simulations results indicating that the $Z_{1/2}$ center is a very effective recombination center in semi-insulating 4H-SiC having detrimental effect on the transient photoconductivity.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 1042-1048
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical and Optical Characteristics of $n-GaSb//n-GaIn_{0.24}AsSb//p-GaAl_{0.34}AsSb$ Heterostructure Photodiode
Autorzy:
Ahmetoglu, M.
Kucur, B.
Andreev, I.
Kunitsyna, E.
Mikhailova, M.
Yakovlev, Y.
Powiązania:
https://bibliotekanauki.pl/articles/1401231.pdf
Data publikacji:
2015-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
73.40.Kp
72.40.+w
Opis:
In the present paper, electrical and optical properties of $n-GaSb//n-GaIn_{0.24}AsSb//p-GaAl_{0.34}AsSb$ double heterostructure (DH) with a diameter of 0.3 mm are reported. The current-voltage (I-V) characteristics of the structure were investigated at several temperatures in both, dark and under the illumination conditions. The effect of illumination was studied at different intensity values. Short circuit current and open circuit voltage as a function of intensity of incident light in photovoltaic mode are investigated.
Źródło:
Acta Physica Polonica A; 2015, 127, 4; 1007-1009
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Vertical Electron Transport in GaN/AlGaN Heterostructures
Autorzy:
Reklaitis, A.
Powiązania:
https://bibliotekanauki.pl/articles/1178371.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Kp
72.20.-i
72.30.+q
Opis:
Nonequilibrium dc and large-signal ac vertical electron transport in GaN/AlGaN heterostructures is investigated by Monte Carlo simulations. The symmetric two-barrier GaN/AlGaN heterostructures are studied. The results of simulations show that polarization charges have a profound effect on dc and large-signal ac characteristics of vertical electron transport in GaN/AlGaN heterostructures. Under certain composition, geometry and doping profile, the GaN/AlGaN heterostructures may become bipolar, i.e., the inversion layers may originate at heterointerfaces due to strong built-in electric fields, which are induced by polarization charges.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 261-266
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
AC Electrical Conductivity and Dielectric Properties of Perovskite $(Pb,Ca)TiO_3$ Ceramic
Autorzy:
El-Mallah, H.
Powiązania:
https://bibliotekanauki.pl/articles/1419850.pdf
Data publikacji:
2012-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.45.Gm
72.20.-i
72.80.-r
Opis:
$Pb_{1 - x }Ca_{x}TiO_3$ perovskite crystalline structure with x = 0, 0.2, 0.6, 0.7, and 0.8 were prepared by mixture method. The ac conductivity and dielectric properties of the studied bulk compositions have been investigated in the frequency range $1 \times 10^3 - 5 \times 10^6 Hz$ and temperature range 303-473 K. The experimental results indicate that the ac conductivity $\sigma_{ac}(\omega),$ dielectric constant ε' and dielectric loss ε" depend on the temperature and frequency. The ac conductivity was found to obey the power law $\omega^{S}$ with the frequency exponent S > 1 decreasing with increasing temperature. The present results are compared to the principal theories that describe the universal dielectric response behavior. Values of dielectric constant ε' and dielectric loss ε" were found to be temperature and frequency dependent and the maximum barrier height $W_{m}$ is calculated.
Źródło:
Acta Physica Polonica A; 2012, 122, 1; 174-179
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Concentration Anomalies of Properties in Pb$\text{}_{1-x}$Ge$\text{}_{x}$Te Solid Solutions
Autorzy:
Rogacheva, E. I
Sinelnik, N. A
Nashchekina, O. N.
Powiązania:
https://bibliotekanauki.pl/articles/1929740.pdf
Data publikacji:
1993-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
61.72.Ji
72.20.-i
71.45.-d
Opis:
The investigation of electrical conductivity, coefficient of thermal electromotive force, Hall coefficient, microhardness and mobility in Pb$\text{}_{1-x}$Ge$\text{}_{x}$Te (x = 0 ÷ 0.1) alloys in the temperature range of 77-300 K was carried out. Anomalies were detected in isotherms of properties in the vicinity of x = 0.008. The anomalies were treated as a manifestation of concentration phase transitions occurring in solid solutions of any kind and associated with existence of critical concentration (percolation threshold) at which the uninterrupted chain of interactions between impurity atoms is formed.
Źródło:
Acta Physica Polonica A; 1993, 84, 4; 729-732
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anomalous Hall Effect in IV-VI Semiconductors
Autorzy:
Dyrdał, A.
Dugaev, V.
Barnaś, J.
Brodowska, B.
Dobrowolski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1810533.pdf
Data publikacji:
2009-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
75.50.Pp
72.25.Dc
Opis:
We consider theoretically the topological contribution to the anomalous Hall effect in narrow-gap IV-VI magnetic semiconductors in which the relativistic terms are relatively large and determine both the non-parabolicity of the energy spectrum and strong spin-orbit interaction. We use the relativistic Dirac model and linear response theory to calculate this contribution. Experimental data on the anomalous Hall effect in these compounds are also presented and discussed.
Źródło:
Acta Physica Polonica A; 2009, 115, 1; 287-289
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency Dependence of Shot Noise in Resonant Diodes under Coherent Tunneling
Autorzy:
Aleshkin, V.
Reggiani, L.
Rosini, M.
Powiązania:
https://bibliotekanauki.pl/articles/1179729.pdf
Data publikacji:
2005-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.70.+m
72.20.-i
72.30.+q
73.23.Ad
Opis:
The current spectral density and the Fano factor of a resonant diode are investigated as a function of frequency up to values just below the inverse of the transit time. We consider the case of coherent tunneling for a symmetric double barrier structure at voltages up to the first current peak at 77 K. At high frequencies the Fano factor is found to become suppressed systematically at a value of 0.25 independently of frequency. This suppression below 0.5 is an indication of coherent against sequential tunneling transport.
Źródło:
Acta Physica Polonica A; 2005, 107, 2; 298-303
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Complex Impedance Investigation of Epitaxial LCMO Thin Films
Autorzy:
Mateev, E.
Nurgaliev, T.
Blagoev, B.
Powiązania:
https://bibliotekanauki.pl/articles/1205437.pdf
Data publikacji:
2014-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
72.80.Ga
72.90.+y
73.61.Le
Opis:
Epitaxial $La_{0.67}Ca_{.33}MnO_3$ (LCMO) thin films by off-axis magnetron sputtering were deposited on $SrTiO_3$ (STO) substrates. Complex impedance measurements (module and phase of the thin film impedance) in frequency range 1-30 kHz are done. Substantial dependence of both: module and phase of the complex surface impedance is observed. The temperature interval scanned is from 77 K to room temperature. The impedance has inductive behavior for temperatures less than the Curie temperature and capacitive for higher temperatures. Reduction of the film thickness from 60 to 30 nm shifts the impedance curves to the lower temperatures.
Źródło:
Acta Physica Polonica A; 2014, 126, 3; 787-789
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electroconductive and Dielectric Properties of Composites Based on Bismuth Vanadate
Autorzy:
Torba, J.
Golubko, N.
Fortalnova, E.
Kaleva, G.
Safronenko, M.
Venskovskii, N.
Politova, E.
Powiązania:
https://bibliotekanauki.pl/articles/1549689.pdf
Data publikacji:
2010-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Tm
77.22.Ch
72.20.-i
61.72.-y
Opis:
Ceramic composites $(100 - n)Bi_{4}V_{2}O_{11-z}-nCe_{0.9}Gd_{0.1}O_{1.9}$ with n=0÷25 wt% were prepared and studied by the X-ray diffraction, dielectric spectroscopy, and impedance methods. Slight increase in the unit cell volume accompanied by monotonous decrease in temperatures and broadening of the α-β and β-γ phase transitions with increasing fluorite content was observed in the composites studied. Increase in melting temperatures of composites with n ≥ 10 with the retention of their high ionic conductivity was also proved.
Źródło:
Acta Physica Polonica A; 2010, 117, 1; 24-26
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Magnetic and Transport Properties of R$\text{}_{3}$Cu$\text{}_{3}$Sb$\text{}_{4}$ Compounds (R = La, Ce, Pr, Nd, and Sm)D
Autorzy:
Skolozdra, R.
Baran, M.
Horyn, A.
Szewczyk, A.
Gorelenko, Yu.
Szymczak, H.
Szymczak, R.
Powiązania:
https://bibliotekanauki.pl/articles/2035550.pdf
Data publikacji:
2002-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.15.-v
72.20.-i
72.15.Jf
75.30.Cr
Opis:
Magnetic susceptibility, electrical resistivity, and thermopower of the series of the R$\text{}_{3}$Cu$\text{}_{3}$Sb$\text{}_{4}$ compounds (R=La-Sm) were measured over the temperature ranges 1.9-300 K (susceptibility and resistivity) and 80-370 K (thermopower). Below 25 K, resistivity of these compounds grows exponentially with decreasing temperature. For some compounds, R = Ce, Sm, a maximum on temperature dependence of resistivity is observed. Ce$\text{}_{3}$Cu$\text{}_{3}$Sb$\text{}_{4}$ compound undergoes a magnetic transition at 12 K.
Źródło:
Acta Physica Polonica A; 2002, 102, 3; 429-435
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Chemical Composition of Liquid Phase and Growth Process on Physical Properties of $Bi_2Se_3,$ $Bi_2Te_3$ and $Bi_2Te_2Se$ Compounds
Autorzy:
Hruban, A.
Materna, A.
Dalecki, W.
Strzelecka, G.
Piersa, M.
Jurkiewicz-Wegner, E.
Diduszko, R.
Romaniec, M.
Orłowski, W.
Powiązania:
https://bibliotekanauki.pl/articles/1492965.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.10.-d
72.15.-v
72.20.-I
73.20.-r
Opis:
We studied synthesis and crystal growth of $Bi_2Te_3,$ $Bi_2Se_3$ and $Bi_2Te_2Se$ compounds by means of vertical Bridgman method. Crystals were grown from stoichiometric melts and under different molar ratio of Bi:Te, Bi:Se or Bi:Te:Se. The obtained crystals were characterized by X-ray diffraction analysis, energy dispersive X-ray spectroscopy, scanning electron microscopy, atomic force microscopy, and the Hall effect measurements. Some of the samples demonstrated insulating bulk behavior, by means of resistivity versus temperature measurements.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 950-953
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron Dynamics in Crystalline Semiconductors
Autorzy:
Zawadzki, W.
Powiązania:
https://bibliotekanauki.pl/articles/1400405.pdf
Data publikacji:
2013-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.28.+d
73.61.Ey
72.20.-i
Opis:
Electron dynamics in crystalline semiconductors is described by distinguishing between an instantaneous velocity related to electron's momentum and an average velocity related to its quasi-momentum in a periodic potential. It is shown that the electron velocity used in the theory of electron transport and free-carrier optics is the average electron velocity, not the instantaneous velocity. An effective mass of charge carriers in solids is considered and it is demonstrated that, in contrast to the "acceleration" mass introduced in textbooks, it is a "velocity" mass relating carrier velocity to its quasi-momentum that is a much more useful physical quantity. Among other advantages, the velocity mass is a scalar for spherical but nonparabolic energy bands ϵ(k), whereas the acceleration mass is not a scalar. Important applications of the velocity mass are indicated. A two-band k·p^ model is introduced as the simplest example of a band structure that still keeps track of the periodic lattice potential. It is remarked that the two-band model, adequately describing narrow-gap semiconductors (including zero-gap graphene), strongly resembles the special theory of relativity. Instructive examples of the "semi-relativistic" analogy are given. The presentation has both scientific and pedagogical aspects.
Źródło:
Acta Physica Polonica A; 2013, 123, 1; 132-138
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Indications for Diamagnetic Shift in the Ground State of Boron in Silicon
Autorzy:
Stöhr, M.
Chroboczek, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/1891427.pdf
Data publikacji:
1991-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.Ht
71.70.-d
72.20.-i
Opis:
Indications for the observation of the diamagnetic shrinkage of the boron acceptor wave function (WF) in Si are reported. Uniaxial stress (X) was used to split the ground state (GS) of the boron acceptor into two energy levels with spatially complementary WF. The magnetic field selectively induces a shrinking of one of the two WF, depending on whether it is applied parallel or perpendicular to the X axis. As a result, the hopping transitions between lower and higher energy levels are redistributed, leading to significant changes in the activation energy ε$\text{}_{3}$. This effect was borne out by experiment.
Źródło:
Acta Physica Polonica A; 1991, 80, 3; 465-468
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electrical Charge Transfer in Complex Oxides
Autorzy:
Shevchuk, V.
Kayun, I.
Powiązania:
https://bibliotekanauki.pl/articles/1550460.pdf
Data publikacji:
2010-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
72.80.-r
77.22.Gm
77.84.-s
Opis:
The electrophysical properties (temperature-frequency dependence of conductivity and dielectric constant, current of depolarization) of complex oxide single crystals (Ca-Ga-Ge-garnet, Ca-Ga-germanate, Pb-, Ca-, Cd-tungstates) are analyzed. The experimental results for different crystallographic axes were obtained in the frequency range 10-$10^{5}$ Hz and temperature range 290-650 K. The main parameters of conductivity and depolarization currents are determined. The nature of polarization charge induced by applied external field is discussed using the model of polarization at hopping exchange of charge between complex dipolar defects and space-inhomogeneous distribution of charge in the sample. Existence of small polarons in the crystals is considered.
Źródło:
Acta Physica Polonica A; 2010, 117, 1; 150-154
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dose Dependences of the Conductivity and Luminescence in ZnSe Single Crystals
Autorzy:
Degoda, V.
Alizadeh, M.
Martynyuk, N.
Pavlova, N.
Powiązania:
https://bibliotekanauki.pl/articles/1030889.pdf
Data publikacji:
2018-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
78.55.Et
29.40.Mc
Opis:
The studies of time-resolved dose dependences of conductivity and luminescence in ZnSe crystals at various temperatures (8, 85, 295, and 430 K) under X-ray and UV-excitation have revealed that dose dependences under X-ray excitation build up much more slowly and are more informative in comparison with UV-excitation. It is due to high penetrating depth of X-ray radiation and respective involvement of a large sample volume in the kinetic processes. Also, due to the local inhomogeneity of the excitation in the absorption of X-quantum, a significant share of the generated electron-hole pairs recombine in this local area creating a scintillation pulse, and not participating in the conductivity. The delay in the onset of the X-ray conductivity buildup at 8 K for several seconds is due to the high efficiency of the localization of free carriers in the traps, all of which become deep at this temperature. The different buildups of various bands of luminescence of irradiation time can be explained by not only different concentration of luminescence centers but also by their localization in various sections of free charge carriers. Dose dependences of the luminescence and conductivity also show that the scintillation pulse amplitudes and the current pulse amplitudes of the X-ray conductivity are not constant during irradiation of the ZnSe crystals.
Źródło:
Acta Physica Polonica A; 2018, 133, 4; 984-989
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semi-conducting properties of titanium dioxide layer on surface of Ti-15Mo implant alloy in biological milieu
Autorzy:
Szklarska, M.
Dercz, G.
Kubisztal, J.
Balin, K.
Łosiewicz, B.
Powiązania:
https://bibliotekanauki.pl/articles/1152668.pdf
Data publikacji:
2016-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
87.85.jj
82.45.Bb
72.20.-i
Opis:
The object of this work was to investigate structure, electrochemical behavior and semiconducting properties of the TiO₂ oxide layer on the Ti-15Mo implant alloy surface in normal and inflammatory conditions of physiological saline solution. X-ray photoelectron spectroscopy measurements confirm the presence of the oxide layer on the Ti-15Mo alloy surface. Electrochemical studies indicate excellent corrosion resistance of Ti-15Mo alloy in physiological saline solution. It was found that the investigated material under normal and inflammatory conditions behave like an insulator and n-type semiconductor, respectively.
Źródło:
Acta Physica Polonica A; 2016, 130, 4; 1085-1087
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation on the Mechanisms of Nitrogen Shallow Implantation Influence on Trap Properties of $SiO_2$/n-Type 4H-SiC Interface
Autorzy:
Król, K.
Sochacki, M.
Szmidt, J.
Powiązania:
https://bibliotekanauki.pl/articles/1363825.pdf
Data publikacji:
2014-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.40.Qv
68.55.ag
72.20.-i
72.25.-b
Opis:
Silicon carbide (SiC) is the only wide-bandgap semiconductor capable of forming native dielectric layer of $SiO_2$ by thermal oxidation. This unique property of SiC combined with its high thermal conductivity and high critical field makes this semiconductor material suitable for high power electronic devices. Unfortunately, the state-of-the art technology does not use the full benefits of the material, especially in the case of MOSFET transistors. This is caused by insufficient electrical parameters of $SiO_2$/SiC interface. Two-component structure of the material and its high density result in high level of interface traps reducing the surface mobility and thus increasing series resistance of the device. One of the proposed methods of reducing the trap density in SiC MOS structure is a shallow nitrogen implantation prior to oxidation. This technique is based on the observation that introducing nitrogen into the $SiO_2$/SiC system results in significant reduction of trap states density and increase of the channel effective mobility. The shallow implantation technique has been reported to be as much effective as nitric oxide annealing which is one of the most effective techniques for oxide quality improvement in case of SiC. Unlike the diffusion based techniques, like postoxidation annealing, implantation of the nitrogen prior oxidation has the possibility of nitrogen concentration control near the oxide interface during oxidation process itself. This property is important since it was shown that the improvement degree is directly proportional to amount of nitrogen built in the vicinity of $SiO_2$/SiC interface during oxidation. However, previous investigations about this technique were inconclusive about the influence of implantation parameters and process conditions on observed effects. Both improvement and deterioration of interface quality was observed by different researchers. This behavior was never explained clearly. The primary objective of this research is to analyze the impact of implantation conditions on electrical properties of $SiO_2$/SiC MOS structure. This analysis is used to evaluate a hypothetical description of physical phenomena during oxidation of shallowly implanted substrates.
Źródło:
Acta Physica Polonica A; 2014, 125, 4; 1033-1037
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Infrared active phonons and optical band gap in multiferroic GdMnO₃ studied by infrared and UV-visible spectroscopy
Autorzy:
Bukhari, S.
Ahmad, J.
Powiązania:
https://bibliotekanauki.pl/articles/1075504.pdf
Data publikacji:
2016-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
63.20.-e
78.20.-e
72.20.-i
73.20.Mf
Opis:
Optical properties of multiferroic GdMnO₃ synthesized by sol-gel method have been investigated by measuring the infrared reflectivity and UV-visible absorption spectra. The infrared reflectivity spectrum of polycrystalline GdMnO₃ in the frequency range 30-7500 cm^{-1} at room temperature contains several phonon modes. The resonant frequency of observed infrared active phonon modes is found comparable with theoretically predicted results. Mean Born effective charges are calculated and discussed in view of the origin of ferroelectricity in GdMnO₃. Three strong absorption peaks observed in the UV-visible spectrum are attributed to the Mn (3d)-electron transitions. The optical band gap ≈1.2 eV is estimated from UV-visible absorption spectrum using Tauc's relation. GdMnO₃ seems to behave like an indirect gap semiconductor.
Źródło:
Acta Physica Polonica A; 2016, 129, 1; 43-48
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase Transitions and Transport Properties of the Bismuth Vanadate-Based $(Bi,La)_{4}(V,Zr)_{2}O_{11-z}$ Ceramics
Autorzy:
Politova, E.
Torba, J.
Fortalnova, E.
Kaleva, G.
Safronenko, M.
Venskovskii, N.
Powiązania:
https://bibliotekanauki.pl/articles/1549668.pdf
Data publikacji:
2010-01
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
64.60.-i
72.20.-i
77.22.Ch
77.22.Gm
Opis:
Ceramic solid solutions $(Bi_{1-y}La_{y})_{4}(V_{1-x}Zr_{x})_{2}O_{11-z}$ with x = 0-0.05, y = 0-0.16 have been prepared by the solid state reaction method. The samples were studied by differential thermal analysis, X-ray diffraction, dielectric spectroscopy, and impedance methods. The concentration and temperature stabilization regions of the polymorphous α-, β-, γ'-, γ-modifications have been determined. The effects observed in dielectric properties, conductivity, and impedance data confirmed the influence both of intrinsic oxygen vacancies and those "pinned" at ferroelectric domain boundaries on the temperature hysteresis of α-β phase transition and their contribution to mechanism of oxygen ion transport.
Źródło:
Acta Physica Polonica A; 2010, 117, 1; 20-23
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
State of the Art Molecular Beam Epitaxy of III-V Compounds
Autorzy:
Foxon, C. T.
Powiązania:
https://bibliotekanauki.pl/articles/1933668.pdf
Data publikacji:
1995-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.60.-q
61.50.Cj
68.55.Bd
72.20.-i
Opis:
This paper discusses molecular beam epitaxy with particular emphasis on the production of state of the art electronic and optoelectronic low dimensional structures and devices. The molecular beam epitaxy process is outlined briefly and the practical problems associated with producing "state of the art" (Al,Ga)As/GaAs structures are considered. Examples include high mobility electron and hole gases, low threshold current lasers and the multi-quantum well solar cells.
Źródło:
Acta Physica Polonica A; 1995, 88, 4; 559-566
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Shielding Effectiveness of Ceramic Bodies Produced with Natural Zeolite
Autorzy:
Kanberoğlu, B.
Şükran Demirkıran, A.
Powiązania:
https://bibliotekanauki.pl/articles/1182903.pdf
Data publikacji:
2014-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Je
07.50.Hp
13.40.-f
72.20.-i
Opis:
In this study, electromagnetic shielding effectiveness of ceramic bodies produced with natural zeolite illuminated by an electromagnetic pulse is investigated. A matrix model is used to calculate the propagation of electromagnetic pulse through sample. Shielding effectiveness of sample is determined for both transmitted electric and magnetic fields. Mathematical theory of the interaction and the shielding effectiveness of the sample is determined as a function of frequency, thickness of the material and the incidence angle of electromagnetic pulse. Zeolites used in this study were supplied from ETI Holding Company located in Turkey. Water was added as a binder and disc samples were shaped by uniaxial dry pressing at pressing pressure of 1.5 tone. Samples were fired in an electric furnace with a heating rate of 10°C/min at 1150C with a period of 60 min. Electrical measurements are performed to determine the dielectric constant and dielectric loss tangent at 25C constant temperature between frequency range from 1 kHz up to 2 MHz.
Źródło:
Acta Physica Polonica A; 2014, 125, 2; 642-644
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Semiconductor Materials for Ultrafast Photoswitches
Autorzy:
Coutaz, J.-L
Powiązania:
https://bibliotekanauki.pl/articles/2035566.pdf
Data publikacji:
2002
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
85.60.-q
85.60.Dw
72.20.-i
72.40.+w
72.80.Ey
42.65.Re
Opis:
This paper gives a review of semiconductor materials that are used to fabricate ultrafast photoswitches. The optoelectrical response of the switches is first described with simple models, from which the material requirements are deduced. The basic principles of the required material properties - ultrashort free carrier lifetime and high mobility, high dark resistivity, and high field breakdown - are explained. Then, the most popular ultrafast semiconductors are listed, together with their characteristics. A special emphasis is put on low-temperature grown GaAs. Finally, two applications of these ultrafast materials are presented, namely antennae for terahertz radiation and all-optical nonlinear devices.
Źródło:
Acta Physica Polonica A; 2002, 102, 4-5; 495-512
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, Roentgenophase Analysis and Physical Properties of $TlIn_{1-x}Er_xSe_2$ Solid Solutions
Autorzy:
Mustafaeva, S.
Kerimova, E.
Gasanov, A.
Powiązania:
https://bibliotekanauki.pl/articles/1402129.pdf
Data publikacji:
2015-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Eh
71.20.-b
71.20.Nr
71.55.-i
72.15.Eb
72.15.Rn
72.20.-i
72.20.Ee
72.20.Jv
72.30.+q
Opis:
The results of high-frequency dielectric measurements on obtained $TlIn_{1-x}Er_xSe_2$ single crystals provided an opportunity to determine the mechanisms of dielectric losses and charge transport, and also to evaluate the density of states at the Fermi level; the average time of charge carrier hopping between localized states, average hopping distance, scattering of trap states near the Fermi level; concentration of deep traps.
Źródło:
Acta Physica Polonica A; 2015, 128, 4; 697-699
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
La-doped and La/Mn-co-doped Barium Titanate Ceramics
Autorzy:
Vijatović Petrović, M.
Bobić, J.
Grigalaitis, R.
Stojanović, B.
Banys, J.
Powiązania:
https://bibliotekanauki.pl/articles/1400499.pdf
Data publikacji:
2013-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.20.Ka
81.40.Ef
77.80.B-
72.20.-i
84.37.+q
Opis:
Barium titanate ceramics doped with 0.3 mol.% lanthanum and co-doped with 0.3 mol.% lanthanum and 0.05 mol.% manganese were investigated. The powders were prepared by a modified polymeric precursor method based on the Pechini process. The ceramics were obtained by sintering at 1300C for 8 h. The influence of dopants on structural changes and grain size reduction was analyzed. The presence of dopants influenced the tetragonality of the barium titanate crystal structure. Reduction of polygonal grain size with dopant addition was noticed. In the doped ceramics, characteristic phase transitions were shifted to lower temperatures in comparison with pure barium titanate. The dielectric permittivity value showed the tendency of a slight increase with lanthanum addition and further increase with adding of manganese. La as a single dopant increased the diffuseness of phase transitions indicating the formation of a diffuse ferroelectric material but in the co-doped ceramics the phase transition diffuseness decreased. The resistivity of the co-doped ceramics was higher than for lanthanum doped ceramics, indicating possible segregation of manganese at grain boundaries that influenced the total resistivity of the material.
Źródło:
Acta Physica Polonica A; 2013, 124, 1; 155-160
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New Semiconductor Devices
Autorzy:
Balestra, F.
Powiązania:
https://bibliotekanauki.pl/articles/1811906.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.-i
73.20.-r
73.21.-b
73.23.-b
73.30.+y
73.40.-c
73.50.-h
73.63.-b
Opis:
A review of recently emerging semiconductor devices for nanoelectronic applications is given. For the end of the international technology roadmap for semiconductors, very innovative materials, technologies and nanodevice architectures will be needed. Silicon on insulator-based devices seem to be the best candidates for the ultimate integration of integrated circuits on silicon. The flexibility of the silicon on insulator-based structure and the possibility to realize new device architectures allow to obtain optimum electrical properties for low power and high performance circuits. These transistors are also very interesting for high frequency and memory applications. The performance and physical mechanisms are addressed in single- and multi-gate thin film Si, SiGe and Ge metal-oxide-semiconductor field-effect-transistors. The impact of tensile or compressive uniaxial and biaxial strains in the channel, of high k materials and metal gates as well as metallic Schottky source-drain architectures are discussed. Finally, the interest of advanced beyond-CMOS (complementary MOS) nanodevices for long term applications, based on nanowires, carbon electronics or small slope switch structures are presented.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 945-974
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Deep Traps Distribution in $TlInS_2$ Layered Crystals
Autorzy:
Isik, M.
Gasanly, N.
Ozkan, H.
Powiązania:
https://bibliotekanauki.pl/articles/1808125.pdf
Data publikacji:
2009-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.20.Jv
72.80.Jc
Opis:
The trap centers and distributions in $TlInS_2$ were studied in the temperature range of 100-300 K by using thermally stimulated currents technique. Experimental evidence was found for the presence of three trapping centers with activation energies 400, 570, and 650 meV. Their capture cross-sections were determined as 6.3 × $10^{-16}$, 2.7× $10^{-12}$, and 1.8× $10^{-11} cm^{2}$, respectively. It was concluded that in these centers retrapping is negligible as confirmed by the good agreement between the experimental results and the theoretical predictions of the model that assumes slow retrapping. An exponential distribution of hole traps was revealed from the analysis of the thermally stimulated current data obtained at different light excitation temperatures. This experimental technique provided a value of 800 meV/decade for the trap distribution.
Źródło:
Acta Physica Polonica A; 2009, 115, 3; 732-737
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Long-Lasting Current Transient Phenomena in TlBr
Autorzy:
Kažukauskas, V.
Ziminskij, A.
Vainorius, N.
Gostilo, V.
Shorohov, M.
Bozhko, V.
Powiązania:
https://bibliotekanauki.pl/articles/1506282.pdf
Data publikacji:
2011-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.20.Jv
72.40.+w
72.60.+g
72.80.Jc
Opis:
The persistent conductivity effects in TlBr were evidenced at the temperatures below about 200 K after the intrinsic light excitation. They were associated with the filling of the trapping states having thermal activation energy of about 0.08-0.12 eV and accompanied by the appearance of the pronounced maximum of the thermally stimulated currents. In this state the enhanced photoconductivity was observed that could be thermally quenched above about 180 K. The quenching is initiated by the emptying of the trapping states having activation energy of 0.63-0.65 eV.
Źródło:
Acta Physica Polonica A; 2011, 119, 2; 268-270
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Excitation of Deep Defects by Intense Terahertz Radiation
Autorzy:
Ganichev, S. D.
Powiązania:
https://bibliotekanauki.pl/articles/2011109.pdf
Data publikacji:
1999-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.20.Ht
72.40.+w
72.30.+q
Opis:
An analysis is done of the ionization of deep impurity centers by high-intensity terahertz radiation, with photon energies tens of times lower than the impurity ionization energy. Under these conditions, ionization can be described as direct tunneling and phonon-assisted tunneling in which carrier emission is accompanied by defect tunneling in configuration space and electron tunneling in the electric field of the radiation. Within a broad range of intensity, frequency, and temperature, the terahertz electric field of the radiation acts like a static field. For very high frequencies and low temperatures an enhancement of tunneling as compared to static fields was observed. The transition between the quasi-static and the high frequency regime is determined by the tunneling time. For the case of deep impurities this is the time of redistribution of the defect vibrational system which depends strongly on temperature and the impurity structure.
Źródło:
Acta Physica Polonica A; 1999, 96, 5; 535-544
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trapping Center Parameters in N-Implanted $Tl_2Ga_2S_3Se$ Single Crystals by Thermally Stimulated Currents Measurements
Autorzy:
Yildirim, T.
Gasanly, N.
Turan, R.
Powiązania:
https://bibliotekanauki.pl/articles/1400156.pdf
Data publikacji:
2013-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.20.Jv
72.80.Jc
Opis:
As-grown $Tl_2Ga_2S_3Se$ crystals have been doped by ion implantation technique. The samples were bombarded at room temperature in the direction perpendicular to the layer by N ion beam of about 120 keV having dose of $1 \times 10^{16} \text{ions}//cm^2$. The effect of N implantation with annealing at 300C was studied by using thermally stimulated current measurements. The investigations were performed in temperatures ranging from 10 to 290 K. The experimental evidence was found for presence of one deep hole trapping center with activation energy of 392 meV. The capture cross-section was calculated as $3.9 \times 10^{-20} cm^2$. Also the concentration of the traps was estimated to be $8.0 \times 10^{11} cm^{-3}$.
Źródło:
Acta Physica Polonica A; 2013, 123, 4; 766-769
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Thermally Stimulated Current Study of Shallow Traps in As-Grown $TlInSe_2$ Chain Crystals
Autorzy:
Gasanly, N.
Yildirim, T.
Powiązania:
https://bibliotekanauki.pl/articles/1505407.pdf
Data publikacji:
2011-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.20.Jv
72.80.Jc
Opis:
Thermally stimulated current measurements were carried out on as-grown $TlInSe_2$ single crystals. The investigations were performed in temperatures ranging from 10 to 260 K with heating rate of 0.3 K $s^{-1}$. The analysis of the data revealed the hole traps levels located at 6 and 57 meV. The activation energies of the traps have been determined using various methods of analysis, and they agree with each other. The concentration (2.8 × $10^{13}$ and 3.4 × $10^{12} cm^{-3}$) and capture cross section (4.1 × $10^{-28}$ and 2.9 × $10^{-26} cm^2$) of the traps were estimated for peaks A and B, respectively. It was concluded that in these centers retrapping was negligible, as confirmed by the good agreement between the experimental results and the theoretical predictions of the model that assumes slow retrapping.
Źródło:
Acta Physica Polonica A; 2011, 119, 3; 437-441
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Metastability of Localized Neutral Donor State In GaAs
Autorzy:
Skierbiszewski, C.
Jantsch, W.
Lübke, K.
Wilamowski, Z.
Suski, T.
Powiązania:
https://bibliotekanauki.pl/articles/1933994.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Fr
71.55.-i
Opis:
Investigations of the photoconductivity of GaAs:Ge under hydrostatic pressure show, in addition to the well known persistent photoconductivity due to the DX state, another giant photoconductivity caused by a neutral localised "A₁" state of the donor. We find that the top of the barrier for the electron recapture to the Α₁ state is pinned to the conduction band edge and the capture cross-section σ(T → ∞) is surprisingly small.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 905-908
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DX Puzzle: Where Are We Now?
Autorzy:
Wilamowski, Z.
Suski, T.
Jantsch, W.
Powiązania:
https://bibliotekanauki.pl/articles/1920958.pdf
Data publikacji:
1992-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
71.55.-i
Opis:
A brief review of the experimental data on the metastable DX-centers in AlGaAs is presented. The experimental proofs of the two-electron nature and of the intermediate, one-electron state of the DX-centers are discussed. We collect the available experimental data on the ground state, electron-emission and capture energies and we discuss the nature of the lattice barrier. The effect of splitting of these energies in AlGaAs alloys and the consequences of the splitting on the capture and emission kinetics are analyzed. The different character of the barrier and of the alloy splitting for donors of the IV and VI group is underlined. The necessity to consider the interdonor Coulomb interaction when discussing the experimental data is also pointed out.
Źródło:
Acta Physica Polonica A; 1992, 82, 4; 561-571
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coulomb versus Madelung Gap: Ordering in a System of Point Charges
Autorzy:
Sobkowicz, P.
Wilamowski, Z.
Kossut, J.
Powiązania:
https://bibliotekanauki.pl/articles/1929618.pdf
Data publikacji:
1993-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.20.Fr
Opis:
Spatial correlations of impurity charges in a mixed valence regime are studied with the use of Monte Carlo simulations. The influence of various kinds of disorder on the one-particle density of states is determined. A continuous transitions from a "soft" Coulomb gap (density of states vanishing only at the chemical potential) to a "hard" gap (with a finite range of energies with vanishing density of states) is found, driven by decreasing amount of built-in disorder in the system. The "hard" Coulomb gap resembles the Madelung gap, found in crystalline arrangements of charges. The similarity reflects the fact that both the Coulomb and Madelung gaps are manifestations of the same phenomenon, resulting from ordering of the positions of point charges, the only difference being the range of correlations.
Źródło:
Acta Physica Polonica A; 1993, 84, 3; 515-518
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoconductivity in GaAlAs:Si Proves Negative U of DX Centers
Autorzy:
Wilamowski, Z.
Jantsch, W.
Ostermayer, G.
Powiązania:
https://bibliotekanauki.pl/articles/1888154.pdf
Data publikacji:
1991-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.20.Jv
71.55.-i
Opis:
The analysis of the temperature dependence of the photoconductivity, amplitude in doped GaAlAs, provides a simple and convincing proof of the negative sign of the Hubbard correlation energy U, strictly speaking of the two-electron nature of the thermal emission process from DX centers. The proof is based on a comparison of the emission activation energy measured per emission event (DLTS) with that measured per electron.
Źródło:
Acta Physica Polonica A; 1991, 80, 2; 283-286
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evidence for Alloy Splitting of Ge Related DX State in Al$\text{}_{x}$Ga$\text{}_{1-x}$As
Autorzy:
Skierbiszewski, C.
Piotrzkowski, R.
Lubke, K.
Powiązania:
https://bibliotekanauki.pl/articles/1992190.pdf
Data publikacji:
1998-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.55.-i
72.20.Fr
Opis:
Thermal emission from resonant DX levels in Ge-doped GaAlAs was studied by measuring the temperature transients of free electron concentration. Pressure was used to fill the levels with electrons. Two emission peaks are observed in AlGaAs:Ge. This enables us to confirm that Ge, similarly to Si dopant, is stabilized upon dangling bond C$\text{}_{3v}$ configuration in AlGaAs. Analysis of experimental data allows us to determine parameters of two components of the DX multilevel system. Evaluated alloy splitting of ground and top of the barrier states: 45 meV is comparable with determined for Si donor.
Źródło:
Acta Physica Polonica A; 1998, 94, 3; 531-533
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-50 z 65

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