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111.
112.
R. Sh. Malkovich 《Technical Physics》2006,51(2):283-286
Coordinate-dependent diffusion in solids, in which case the probability of presence of a vacancy, φ, and the probability of migration, γ, depend on coordinate x is analyzed. The coordinate dependence of parameters φ and γ is shown to cause the drift component of the diffusion flux. In the presence of this component, the direction of atomic motion may coincide (enhanced diffusion) or not coincide (retarded diffusion and up-diffusion) with the direction of the diffusion component. The criteria of enhanced diffusion, retarded diffusion, and up-diffusion are established. These criteria are specified by the behavior of function F(x)=φ(x)/γ(x). 相似文献
113.
A new approach to observing the effect of electromagnetically induced transparency in gamma optics is proposed. The propagation of a resonant photon in a 57Fe magnetic medium in an applied rf field is considered for this purpose. It is shown that, under crossing-anticrossing conditions, a resonant rf field substantially changes the gamma-optical properties of the medium, which become dependent on the parameters of the field. This opens the possibility for exercising a coherent control of the photon group velocity and a controllable filtration of unpolarized gamma radiation in a sample. 相似文献
114.
B.G. Tagiyev G.M. Niftiyev S.M. Bashirov F.Sh. Aydaev 《Solid State Communications》1984,50(7):689-691
The current-voltage characteristics (CVC) at different temperatures, the temperature dependence of electric conductivity [σ(T)] and the currents of thermostimulated depolarization (TSD) have been studied in GaSe <0.05 at.% Co> on a combined basis.The location depth (Et=0.57eV) and the concentration of traps (Nt=2.7x1012cm?3) have been determined from the temperature dependence of the trapping factor. In the course of TSD investigations, levels with location depths of 0.28±0.02 and 0.57±0.03 eV have been revealed. It is noted that traps with the energy of 0.57±0.03 eV are found both with TSD measurements and on the basis of the temperature dependence of the electric conductivity and the trapping factor.It has been established that the hole centres above the valence band are responsible for the CVC, σ(T) and TSD. The location depths, concentrations and trapping cross-sections of these centres have been determined. 相似文献
115.
Theoretical analysis of the radiation effect on transient behavior of an optoelectronic integrated device composed of a heterojunction phototransistor and a light emitting diode is studied theoretically. First, the transient behavior and the rise time of this device before radiation are investigated based on the frequency response of the constituent devices and the optical feedback inside the device. Second, the effect of neutron irradiation flux on the transient behavior of this device is theoretically studied. The results show that, by increasing the optical feedback inside the device, the rise time in the amplification mode is increased along with an increasing output, while that in the switching mode can be reduced effectively, and the neutron irradiation reduces the transient response and the rise time in both the amplification and switching modes. This type of model can be exploited as optical amplifier, optical switching device, and other applications. 相似文献
116.
117.
A. S. Saidov Sh. N. Usmonov M. U. Kalanov A. N. Kurmantayev A. N. Bahtybayev 《Physics of the Solid State》2013,55(1):45-53
Films of the solid solutions Si1 ? x Sn x (0 ≤ x ≤ 0.04) on Si substrates have been grown by liquid phase epitaxy. The structural features of the films have been investigated using X-ray diffraction. The temperature behavior of current-voltage characteristics and the spectral dependence of the photocurrent for the heterostructures p-Si-n-Si1 ? x Sn x (0 ≤ x ≤ 0.04) have been analyzed. The grown epitaxial films of the solid solutions Si1 ? x Sn x (0 ≤ x ≤ 0.04) have a perfect single-crystal structure with a (111) orientation and a subgrain size of 60 nm. In the epitaxial films at the Si-SiO2 interfaces between silicon subgrains and SiO2 nanocrystals, where there are many sites with a high potential, the Sn ions with a high probability substitute for the Si ions and encourage the formation of Sn nanocrystals with different orientations and, as follows from the analysis of the X-ray diffraction patterns, with different sizes: 8 nm (for the (101) orientation) and 12 nm (for the (200) orientation). The current-voltage characteristics of the heterostructures p-Si-n-Si1 ? x Sn x (0 ≤ x ≤ 0.04) are described by the exponential law J = J 0exp(qV/ckT) at low voltages (V < 0.2 V) and the square law J = (9qμ p τ p μ n N d /8d 3)V 2 at high voltages (V > 1 V). These results have been explained by the drift mechanism of charge carrier transport in the electrical resistance relaxation mode. 相似文献
118.
The optical absorption coefficient γ of a thin film of a Peierls semiconductor has been calculated in the dipole approximation for direct interband transitions as a function of intensity I and central frequency ω0 of a quasi-monochromatic frequency spectrum near the lower optical transition edge. It is shown that the γ(I, ω0) dependence is strongly nonlinear, and within a certain region of I and ω0 variation, not single-valued, which indicates the onset of resonator-free optical bistability with increasing absorption. 相似文献
119.
Yu. V. Vasil’ev R. R. Abzalimov Sh. K. Nasibullaev R. F. Tuktarov F. Hauke U. Reuther A. Hirsch T. Drewello 《Physics of the Solid State》2002,44(3):554-556
The formation and decay of negative molecular ions of azafullerenes and their hydrogenated derivatives are investigated by mass spectrometry. The mechanisms of resonant electron capture and the lifetimes of negative molecular ions with respect to the electron autodetachment in azafullerene molecules are discussed. A comparative analysis of the data obtained for azafullerenes and hydrogenated fullerene derivatives is carried out. 相似文献
120.
R. A. Ganeev A. I. Ryasnyanskii M. K. Kodirov Sh. R. Kamalov V. A. Li R. I. Tugushev T. Usmanov 《Technical Physics》2002,47(8):991-995
Nonlinear optical parameters (nonlinear refractive indices and nonlinear absorption coefficients) of solutions of polyvinylpyrrolidone doped by cobalt to various concentrations are measured at the lasing and second-harmonic wavelengths of a picosecond Nd:YAG laser (λ=1064 and 532 nm, respectively, and τ=35 ps). Data on optical limitation in these solutions are presented. The absence of nonlinear absorption in the IR spectral range and its significant effect in the visible range are demonstrated. Optical limitation at a wavelength of 1064 nm is related to defocusing, whereas at 532 nm, this effect is caused by two-photon absorption and partially by inverse saturated absorption and defocusing. Nonlinear optical parameters of metal-polymer complexes are reported. 相似文献