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71.
Electron-irradiation induced defects in semi-insulating (SI) InP wafers with Fe concentration ranging from 1.5×1015 to 2.5×1015 cm−3, which have been obtained by multiple-step wafer annealing (MWA) under phosphorus vapor pressure, were studied using a thermally stimulated current (TSC) method. New traps, e1, e2, e3, e4 and e5, with activation energies of 0.22, 0.28, 0.37, 0.44 and 0.46 eV, respectively, were observed. Based upon the annealing behavior of traps and the calculated defect levels, traps e1 and e5 produced by the irradiation with electron doses above 1×1015 cm−2 were linked to InP and PIn antisite defects, respectively, that probably form complexes. Traps e3 and e4 produced by the irradiation with doses above 1×1014 cm−2 were associated with In and P vacancy related defects, respectively. 相似文献
72.
M. Salvato F. Bobba G. Calabrese C. Cirillo A. M. Cucolo A. De Santis A. Vecchione C. Attanasio 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,51(1):79-85
Resistivity vs. temperature measurements on
La0.7Ca0.3MnO3/YBa2Cu3O7-δ
/La0.7Ca0.3MnO3 (LCMO/YBCO/LCMO) trilayers with different
YBCO thickness, were performed in external magnetic field H up to 8 T. By
evaluating the activation energy U from the slope of the resistivity
Arrhenius plot, a strong depression of U has been observed when decreasing
the YBCO layer thickness and the absolute U values appear to be reduced with
respect to the values reported in literature in the case of YBCO thin films
and YBCO/insulating multilayers. Moreover, a logarithmic U vs. H dependence is
shown both in the case of thick and thin YBCO layers indicating the
formation of a two dimensional vortex lattice. The experimental data are
discussed considering the strong influence of the ferromagnetic LCMO on the
superconducting YBCO properties which reduces the effective YBCO thickness
more than predicted by the conventional theories. 相似文献
73.
Qiang Wang Daocheng Pan Xiangling Ji Lijia An Bingzheng Jiang 《Journal of luminescence》2006,118(1):91-98
A new solvothermal route has been developed for synthesizing the size-controlled CdSe nanocrystals with relatively narrow size distribution, and the photoluminescence (PL) quantum yields (QYs) of the nanocrystals can reach 5-10%. Then the obtained CdSe nanocrystals served as cores to prepare the core/shell CdSe/CdS nanocrystals via a two-phase thermal approach, which exhibited much higher PL QYs (up to 18-40%) than the CdSe core nanocrystals. The nanocrystal samples were characterized by ultraviolet-visible (UV-vis) absorption spectra, PL spectra, wide-angle X-ray diffraction (WAXD), X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM). 相似文献
74.
A. Gold 《Zeitschrift für Physik B Condensed Matter》1994,94(4):395-399
We present an analytical model for the Coulomb interaction effects in quantum wires forming a nanochannel array. We study the elementary excitations (plasmons and electron-hole excitations) of electron arrays forming three-dimensional structures. The plasmon spectrum of boson arrays is also calculated. Our model applies to bulk material with one-dimensional conduction channels as realized in organic or polymer crystals and in nanochannel array glasses. 相似文献
75.
任意环的两个交换性定理 总被引:4,自引:0,他引:4
本文证明了一个包含很广的任意PI-环的交换性定理,并由此推广了著名的Herstein定理. 相似文献
76.
We report the use of conducting precision fabrics as transparent and flexible electrode for organic semiconductor‐based thin film devices. Precision fabrics have well‐defined mesh openings, excellent flexibility and are fabricated by high‐throughput roll‐to‐roll manufacturing. Optimized fabrics reached light transmittance over 95% throughout the visible and near infrared spectra. A significant part of the transmitted light is scattered, which is particularly advantageous for solar cell applications. Surface resistivity is as low as ~3 Ohms/square, which decreases Ohmic losses when scaling up to large area devices. We demonstrate that solar cells fabricated onto these electrodes show very similar characteristics to those prepared on ITO. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
77.
De-Hone Lin 《Physics letters. A》2009,373(31):2634-2636
The analytic result of the Aharonov-Bohm effect for its influence on the oscillation of a two-dimensional charge density around a short range potential is given. Without losing generality, the cases of δ-function and hard disc potentials were examined. Numerical calculations show that the interferences among quantum particles are greatly influenced by the nonlocal effect, which leads to the modulation of phase and amplitude of the oscillation of charge density. Since the presence of a nonlocal influence of the Aharonov-Bohm effect on charged particles is universal, the results in the specific potentials examined are expected to appear also in other general systems which may be beneficial to the study of nanotechnology. 相似文献
78.
Effect of Electrochemical Treatment in a Lithium Chloride Solution on Field Emission from Carbon Nanotubes 下载免费PDF全文
Carbon nanotubes (CNTs) are electrochemically treated in a lithium chloride solution at a concentration 0. 1 mol/L The field emission properties of the CNTs are investigated at different temperatures before and after the electrochemical treatment. After treatment, the turn-on voltage to produce field emission current of 10μA decreases from 4.2kV to 2. 7kV and the field emission current increases distinctly, but the stability falls off. Based on the Fowler-Nordheim plot, the values of the work function for the CNTs are calculated, which reveals that work function decreases after the electrochemical treatment. These results are attributed to the decrease of the work function of the carbon nanotubes. 相似文献
79.
L. B. Hovakimian 《Applied Physics A: Materials Science & Processing》2009,96(1):255-257
Within the framework of strong-coupling theory we study the effect of highly negatively charged threading dislocations on
the electron mobility collapse in n-GaN layers. An analytical expression is derived showing the way in which the electrically active dislocations establish the
critical carrier concentration at which the collapse occurs. Results are presented suggesting that the experimental collapse
data can be utilized for determining the characteristic magnitude of the statistical filling factor of dislocation related
traps in the GaN bandgap. 相似文献
80.
Exact solution of the one-dimensional spin-\frac{\mathsf 3}{\mathsf 2} Ising model in magnetic field
A. Avella F. Mancini 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,50(4):527-539
In this paper, we study the Ising model with general spin S in
presence of an external magnetic field by means of the equations of
motion method and of the Green's function formalism. First, the
model is shown to be isomorphic to a fermionic one constituted of
2S species of localized particles interacting via an intersite
Coulomb interaction. Then, an exact solution is found, for any
dimension, in terms of a finite, complete set of eigenoperators of
the latter Hamiltonian and of the corresponding eigenenergies. This
explicit knowledge makes possible writing exact expressions for the
corresponding Green's function and correlation functions, which turn
out to depend on a finite set of parameters to be self-consistently
determined. Finally, we present an original procedure, based on
algebraic constraints, to exactly fix these latter parameters in the
case of dimension 1 and spin
. For this latter case and,
just for comparison, for the cases of dimension 1 and spin
[F. Mancini, Eur. Phys. J. B 45, 497 (2005)] and
spin 1 [F. Mancini, Eur. Phys. J. B 47, 527 (2005)],
relevant properties such as magnetization 〈S 〉 and
square magnetic moment 〈S2 〉, susceptibility and
specific heat are reported as functions of temperature and external
magnetic field both for ferromagnetic and antiferromagnetic
couplings. It is worth noticing the use we made of composite
operators describing occupation transitions among the 3 species of
localized particles and the related study of single, double and
triple occupancy per site. 相似文献