56 research outputs found
Statistical model structure of A1−xZxB2 Laves phase C15 system—the superconducting alloy Ce1−xLaxRu
No full textThe local structure of the Ce1−xLaxRu2 system measured by EXAFS is re-examined and correlated to the statistical ad hoc model recently applied to the sphalerite, wurtzite, and other intermetallic ternary alloys. Deconvolution of the EXAFS data shows that the Ce1−xLaxRu2 ternary system is essentially a mixture of CeRu2 and LaRu2 binary alloys with a small proportion of the Ce0.5La0.5Ru2 ternary configuration, which is maximum for the intermediate concentration. Moreover, the analysis reveals that while the LaRu2 configuration exhibits a Bernoulli random distribution, the presence of a Ce atom affects both the CeRu2 and Ce0.5La0.5Ru2 distributions, strongly favoring the configuration with the CeCe pair, while keeping rare that with a single Ce ion
Ion distribution preferences in ternary crystals Zn xCd 1−x Te, Zn 1−x Hg xTe and Cd 1−x Hg xTe
No full textSimilar ternary semiconductors are sometimes associated with widely different structures characterized by different site occupation preferences. We have used far-infrared (FIR) spectra to determine the site occupation preference coefficients for three ternary semiconductor alloys: ZnCdTe, ZnHgTe and CdHgTe and, in the case of ZnHgTe, have validated it by X-ray absorption fine structure (EXAFS) analysis. While ZnCdTe spectra exhibit the canonical configuration with eight phonon lines free of vibrational defect lines and only a slight departure from a random ion distribution, CdHgTe spectra show the eight canonical phonon modes plus an additional vibrational defect line and constant preference coefficients. In contrast, two defect lines and only four modes characterize ZnHgTe spectra, as extreme preferences prevent the formation of two of the five expected tetrahedral configuration arrangements. Moreover, for this system, comparison with EXAFS data points out the vibrational nature of both the extra lines. The analysis clearly shows that assuming a Bernoulli distribution of the component configurations of semiconductors may lead to wrong assessments of the evolution of its properties with relative content.JRC.D.5 - Food Safety and Qualit
Vibrational spectra of hydrogenated CdTe
No full textInfrared spectroscopy may deliver important information on defects created in CdTe monocrystals grown from Cd and Te components purified in a hydrogen atmosphere before the crystallization process. Reflectivity spectra on different CdTe samples were collected with a FTIR spectrometer using a standard Hg lamp and the IR synchrotron radiation source of the DAFNE synchrotron facility at Frascati. In the 500-2000 cm(-1) frequency region, the characteristic vibrational spectra of oxygen and hydrogen bounded to Cd and Te in the monocrystalline CdTe were observed. Moreover the rich fine structure around the CdTe phonon frequency range has been resolved and the preliminary assignment of several lines has been performed. (c) 2005 WILEY-VCH Verlag GmbH I Co. KGaA, Weinheim
Low Temperature Physics V. 30, I. 11
No full textLow Temperature Physics -- November 2004
Volume 30, Issue 11, pp. 825-936
XV ural international winter school on physics of semiconductors
Full Text: PDF (16 kB)
LOW-DIMENSIONAL AND SUPERCONDUCTING SYSTEMS
Electronic properties and superconductivity of low-dimensional carbon structures
V. A. Kulbachinskii
Full Text: PDF (270 kB)
Conductivity of a two-dimensional electron gas in magnetic field in the presence of microwave radiation
I. I. Lyapilin and A. E. Patrakov
Full Text: PDF (418 kB)
Neutral and charged excitons in a CdTe-based quantum well
J. A. Gaj, P. Plochocka, C. Radzewicz, P. Kossacki, W. Maslana, J. Cibert, and S. Tatarenko
Full Text: PDF (78 kB)
Magnetotransport probing of the quality of the heterointerfaces and degree of symmetry of the potential profile of quantum wells in the valence band of the Ge1–xSix/Ge/Ge1–xSix heterosystem
M. V. Yakunin, G. A. Alshanskii, Yu. G. Arapov, V. N. Neverov, G. I. Harus, N. G. Shelushinina, O. A. Kuznetsov, A. de Visser, and L. Ponomarenko
Full Text: PDF (89 kB)
Parallel magnetotransport in multiple quantum well structures
E. M. Sheregii, D. Ploch, M. Marchewka, G. Tomaka, A. Kolek, A. Stadler, K. Mleczko, W. Strupinski, A. Jasik, and R. Jakiela
Full Text: PDF (173 kB)
Nonmonotonic temperature dependence of the resistivity of p-Ge/Ge1–xSix in the region of the metal–insulator transition
Yu. G. Arapov, G. I. Harus, N. G. Shelushinina, M. V. Yakunin, V. N. Neverov, O. A. Kuznetsov, L. Ponomarenko, and A. De Visser
Full Text: PDF (74 kB)
Formation of a self-consistent double quantum well in a wide p-type quantum well
G. A. Alshanskii and M. V. Yakunin
Full Text: PDF (42 kB)
Oscillations of the conductivity of a two-dimensional electron gas in the presence of microwave radiation
A. E. Patrakov and I. I. Lyapilin
Full Text: PDF (48 kB)
Molecular epitaxy and the electronic properties of Ge/Si heterosystems with quantum dots
A. V. Dvurechensky, A. I. Nikiforov, O. P. Pchelyakov, S. A. Teys, and A. I. Yakimov
Full Text: PDF (317 kB)
On the nature of the anisotropy of the resistivity of Nd2–xCexCuO4 + delta with different cerium and oxygen concentrations
A. I. Ponomarev, T. B. Charikova, A. N. Ignatenkov, A. O. Tashlykov, and A. A. Ivanov
Full Text: PDF (90 kB)
IMPURITY STATES IN TRANSIENT METAL SEMICONDUCTORS
Mechanisms of radiative and nonradiative recombination in ZnSe:Cr and ZnSe:Fe
M. Godlewski, M. Surma, V. Yu. Ivanov, and T. P. Surkova
Full Text: PDF (88 kB)
Effects of resonance scattering of electrons by donor impurities in semiconductors
V. I. Okulov
Full Text: PDF (93 kB)
Electrophysical properties of semimagnetic solid solutions Hg1–xMnxTe
I. M. Nesmelova, V. N. Ryzhkov, M. I. Ibragimova, and V. Yu. PetukhovKazan Physicotechnical Institute, Kazan Research Center of the Russian Academy of Sciences, Kazan 420029, Russia
Full Text: PDF (74 kB)
PHASE TRANSITIONS AND STRUCTURES OF SEMICONDUCTORS COMPOUNDS
Nonequilibrium processes and ferroelectric phase transition in PbGeTe(Ga) crystals
B. A. Akimov, V. V. Pryadun, D. R. Khokhlov, L. I. Ryabova, V. I. Shtanov, and E. I. Slynko
Full Text: PDF (65 kB)
Ultrasonic investigation of a phase transition in ZnSe:Ni
V. V. Gudkov, S. B. Petrov, A. T. Lonchakov, I. V. Zhevstovskikh, V. I. Sokolov, and N. B. Gruzdev
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Dynamics of the insulator–conductor transition initiated by high pressure in ammonium halides
G. V. Tikhomirova and A. N. Babushkin
Full Text: PDF (69 kB)
Statistical strained-tetrahedron model of local ternary zinc blende crystal structures
B. V. Robouch, E. M. Sheregii, and A. Kisiel
Full Text: PDF (216 kB)
Wavelet analysis and its application in tunneling and x-ray spectroscopy
M. V. Chukalina, Yu. V. Dubrovskii, and H. Funke
Full Text: PDF (292 kB)Archived web conten
Manifestation of defects in phonon spectra of binary zinc-blende compounds
No full textIt is interesting to consider the problem of the presence of defects in the semiconductor binary compounds by observing their elemental tetrahedron distortions, caused by the creation of vacancies and interstitial atoms within the tetrahedra and so on. Our model thus considers the system A(Vz(x)Z(1-x)) and (A(1-y)Va(y))Z as composed of five defect tetrahedron configurations where A is a cation atom, Z an anion atom, V-alpha-cation vacancy, V-z-anion vacancy. In this communication we present far IR (FIR) spectra obtained at the DAFNE facility of Laboratori Nazionali di Frascati (INFN) using its synchrotron radiation. Two samples of CdTe are considered: sample-1 was grown by the PVT technique and sample-2 using the same technique but on the basis of, polycrystalline CdTe previously purified from oxygen in hydrogen atmosphere
Effect of band inversion on the phonon spectra of Hg1-xZnxTe and Hg1-xCdxTe semiconductor alloys
No full textFirst interpretation of phonon spectra of quaternary solid solutions using fine structure far-IR reflectivity by synchrotron radiation
No full textIn this work, we present and discuss far-infrared (FIR) reflectivity spectra obtained using infrared synchrotron radiation in different ZnxCdyHg1-x-yTe (ZMCT) quaternary alloys. Reffectivity spectra were measured at the DAFNE-light facility of the INFN-LNF with samples placed under vacuum inside a BRUKER Equinox 55 interferometer. Samples were cooled in a helium cryostat in a temperature range from about 20 K to 300 K. The obtained spectra were standard Kramers-Kronig transformed to obtain the imaginary part of the dielectric functions, then unfolded into a set of Lorentzian oscillators. The fitting procedure yields a total of 21 lines in the ZnxCdyHg1-x-yTe reflection spectra of these quaternary alloys. Sixteen lines have been correlated to ternary spectral contributions of the different components: CdHgTe, ZnHgTe and CdZnTe (with a precision of +/- 1.5cm(-1)). In the wave number range between 108 cm(-1) and 190 cm(-1) the oscillator frequencies have been attributed to the spectral lines of these quaternary alloys. (c) 2006 Elsevier B.V. All rights reserved
Etude de la topographie du champ magnétique et optique des trajectoires de sortie des particules dans un accélérateur FFAG du type Ohkawa
No full text
Etude de l'optique des trajectoires de sortie des particules dans un accélérateur FFAG du type Ohkawa
No full text- …
