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Wyszukujesz frazę "72.20.-I" wg kryterium: Temat


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:
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:
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:
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:
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:
Features of Energy Spectrum of Pb$\text{}_{1-x}$Mn$\text{}_{x}$Te Doped with V
Autorzy:
Artamkin, A. I.
Dobrovolsky, A. A.
Dziawa, P.
Story, T.
Slynko, E. I.
Slynko, V. E.
Ryabova, L. I.
Khokhlov, D. R.
Powiązania:
https://bibliotekanauki.pl/articles/2046904.pdf
Data publikacji:
2006-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Nr
71.28.+d
71.55.-i
72.40.+w
Opis:
Recently new effects that are not characteristic of undoped lead telluride, such as the Fermi level pinning, giant negative magnetoresistance, were observed in Pb$\text{}_{1-x}$Mn$\text{}_{x}$Te alloys doped with transition and rare earth elements - Cr, Mo, Yb. We have studied transport and magnetic properties of Pb$\text{}_{1-x}$Mn$\text{}_{x}$Te doped with another transition element - vanadium. A series of Pb$\text{}_{1-x}$Mn$\text{}_{x}$Te(V) samples of different composition and degree of doping was investigated. It was observed that the resistivity demonstrates activation behavior at low temperatures for the samples with considerable amount of vanadium as well as for the samples without vanadium. The activation energy is proportional to the Mn content. In some of the samples, photoconductivity was observed at low temperatures. The results are discussed in terms of a model assuming formation of the impurity level by the vanadium impurity and the effect of the Fermi level pinning by this level.
Źródło:
Acta Physica Polonica A; 2006, 110, 2; 151-156
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:
Polaron Problem in Quantum Wells
Autorzy:
Bardyszewski, W.
Prywata, M.
Powiązania:
https://bibliotekanauki.pl/articles/1934053.pdf
Data publikacji:
1995-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
72.80.Ey
71.38.+i
73.20.Dx
Opis:
The effect of polar interaction between an electron in a quantum well and bulk longitudinal optical phonons is analysed. Electron spectral density function is calculated in the lowest order cumulant approximation. The position and linewidth of the quasiparticle peak are obtained as a function of quantum well width and temperature.
Źródło:
Acta Physica Polonica A; 1995, 88, 5; 969-973
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Scattering of Excitons by Phonons in Quantum Wells
Autorzy:
Bardyszewski, W.
Prywata, M.
Powiązania:
https://bibliotekanauki.pl/articles/1947245.pdf
Data publikacji:
1996-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Dx
71.38.+i
72.80.Ey
Opis:
A method to describe the effects of the exciton-optical phonon interaction is presented using the cumulant expansion approximation. The functional-integral technique of coherent phonon states is used in order to justify the commonly used model Hamiltonian and generate the proper perturbation series. The influence of the mutual electron-hole screening on the polaronic effects in quantum wells is analyzed.
Źródło:
Acta Physica Polonica A; 1996, 90, 4; 715-718
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:
Electrical Resistivity and Electronic Structure of the $Tb_{x}Gd_{1-x}Ni_3$ System
Autorzy:
Chełkowska, G.
Bajorek, A.
Chrobak, A.
Kwiecień-Grudziecka, M.
Powiązania:
https://bibliotekanauki.pl/articles/1427391.pdf
Data publikacji:
2012-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.20.Eh
71.20.Lp
72.15.-v
72.10.Di
79.60.-i
Opis:
In the paper the electric properties and electronic structure of the intermetallic $Tb_{x}Gd_{1-x}Ni_3$ compounds are presented. The partial replacement of Gd by Tb atoms causes the decrease of the Curie temperature $(T_{C})$ and the increase of the residual resistivity. According to the Matthiessen rule the scattering mechanisms in ρ(T) have been analyzed. Moreover, the reduced form of the electrical resistivity $ρ_{Z} (T - T_{0})$ indicates a deviation from the linearity for x > 0.2. This kind of behaviour can be attributed to density of d states near by the Fermi level $(E_{F})$ which are dominated by Ni 3d states. The valence band spectra as well as the core level lines have been analyzed as the influence of Tb/Gd substitution on the electronic structure.
Źródło:
Acta Physica Polonica A; 2012, 121, 5-6; 1139-1141
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:
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:
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:
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

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