共查询到10条相似文献,搜索用时 15 毫秒
1.
S. Y. Yang X. L. Zhang Z. D. Lou Y. B. Hou 《The European Physical Journal B - Condensed Matter and Complex Systems》2007,59(2):151-154
Electroluminescence (EL) of bilayer organic light-emitting diodes based on N,N'-diphenyl-N,N'-bis(3-methylphenyl)-(1,1'-biphenyl)-4,4'-diamine
(TPD) and 2-(4'-biphenyl)-5-(4”-tert-butylphenyl)-1,3,4-oxadiazole (PBD) were reported. The EL spectra of bilayer device ITO/TPD/PBD/Al consist of monomolecular
emission from TPD, exciplex emission and charge carriers cross recombination at the TPD/PBD interface. By varying the thickness
of each organic layer while keeping the thickness of the whole device constant, three kinds of bilayer devices were fabricated
and their EL and photoluminescence spectra were compared with each other, and our experimental data show that charge tunneling
and cross recombination coexist at the TPD/PBD interface, and these two processes compete with each other under high electric
fields. 相似文献
2.
H.-K. Zhao J. Wang 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,9(3):513-524
The time-dependent transport through an ultrasmall quantum dot coupling to two electron reservoirs is investigated. The quantum
dot is perturbed by a quantum microwave field (QMF) through gate. The tunneling current formulae are obtained by taking expectation
values over coherent state (CS), and SU(1,1) CS. We derive the transport formulae at low temperature by employing the nonequilibrium
Green function technique. The currents exhibit coherent behaviors which are strongly associated with the applied QMF. The
time-dependent currents appear compound effects of resonant tunneling and time-oscillating evolution. The time-averaged current
and differential conductance are calculated, which manifest photon-assisted behaviors. Numerical calculations reveal the similar
properties as those in classical microwave field (CMF) perturbed system for the situations concerning CS and squeezed vacuum
SU(1,1) CS. But for other squeezed SU(1,1) CS, the tunneling behavior is quite different from the system perturbed by a single
CMF through gate. Due to the quantum signal perturbation, the measurable quantities fluctuate fiercely.
Received 28 May 1998 相似文献
3.
A model is proposed that treats electrons at surfaces as a combination of two-dimensional and three-dimensional degrees of
freedom. This yields a simple formula for the surface state induced resonant enhancement of the transfer of electrons through
a surface. The model also yields analytic approximations for the transition between two-dimensional and three-dimensional
distance laws in the correlations between electrons in surface states.
Received 6 August 2002 Published online 31 October 2002
RID="a"
ID="a"e-mail: rainer@sask.usask.ca 相似文献
4.
Y. P. Chen Y. E. Xie X. H. Yan 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,49(3):333-338
We have studied the transmission resonances for a confined array of
antidots, using the lattice Green's function method. Two kinds of resonant
peaks via quasibound states are found. One kind of resonant peak corresponds
to the split quasibound states. The split states originate from the
superposition of quasibound states respectively localized in different (T or
crossed) junctions, while the number of quasibound states in each junction
is associated with the arm-width of the junction. Electrons in these split
states are mainly localized in the junctions. The other kind of resonant
peaks correspond to the high quasibound states which exist in (transverse
and longitude) multi-period confined arrays of antidots. It is interesting
to note that electrons in some of the high quasibound states are mainly
localized in the intersection of the junctions rather than in the junctions
themselves. 相似文献
5.
M. Saint Jean S. Hudlet C. Guthmann J. Berger 《The European Physical Journal B - Condensed Matter and Complex Systems》1999,12(4):471-477
In triboelectric phenomena, electric charges are transferred when two materials are touched or rubbed together. We present
in this paper a study of this effect performed on metallic oxides at the nanometric scale by an Atomic Force Microscope in
the resonant mode. We show that following the electrification processes, positive or negative charges can be deposited. From
our experimental data, we conclude that the charge transfer results in an equilibrium final state, the occupied states in
the gap being “surface states” with large density and spread under the surface along a characteristic distance of about 100
nm.
Received 18 March 1998 and Received in final form 8 July 1998 相似文献
6.
P. A. Ignatiev V. S. Stepanyuk L. Niebergall P. Bruno J. Berakdar 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(3):547-551
We present first theoretical evidence revealing the influence of structural changes on the spin-polarized surface states of
large Co nanoislands grown on
Cu(111). The minority density of electronic states possesses
a pronounced peak whose energetic position depends sensitively on
the Co layers stacking order. Our results suggest a way to deduce
the stacking order of large Co nanoislands using scanning tunnelling
microscopy/spectroscopy. 相似文献
7.
L. Yang J. Chen H. Yang J. Dong 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,33(2):215-219
We have constructed four types single-wall carbon nanotube intramolecular junctions (IMJs) of (5,5)/(8,0), (5,5)/(10,0), (5,5)/(9,0)A, and (5,5)/(9,0)B along a common axis, and calculated their electronic and transport properties using a tight binding-based Green's function
approach that is particular suitable for realistic calculation of electronic transport property in extended system. Our results
show that quasi-localized states can appear in the metal/semiconductor heterojunctions ((5,5)/(8,0) and (5,5)/(10,0)junctions),
which is desirable for the design of a quantum device; and the conductance of M-M IMJs is very sensitive to the connectivity
of the matching tubes, certain configurations of connection completely stop the flow of electron, while others permit the
transmission of the current through the interface. These results may have implications for the device assembly and manipulation
process of all carbon nanotubes-based microelectronic elements.
Received 14 January 2003 / Received in final form 25 February 2003 Published online 4 June 2003
RID="a"
ID="a"e-mail: lfyzz@yahoo.com.cn 相似文献
8.
M.P. Lissitski A. Naddeo C. Nappi A. Tagliacozzo V.N. Gubankov R. Monaco M. Russo 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(3):309-314
Measurements of differential resistance in a superconductor-degenerate semiconductor junction Nb
-
n
+ +
GaAs at T
= 1.6 K show close similarity to those for a conventional superconductor-insulator- normal metal junction, except for the position
of the minimum which is located at 3.6 meV. Using a simple model for the charge screening at the Schottky barrier, we give
an argument why this minimum is by far displaced with respect to the superconducting gap energy ( Δ
g
= 1.5 meV for bulk Nb). We argue that a rebuilding of the density of states takes place at the barrier, due to the imperfect metal
screening in the degenerate semiconductor. Energy states close to the degenerate semiconductor Fermi energy are depleted at
the barrier and are not available for tunneling, up to an energy Eg which adds to the superconducting gap Δ
g
.
Received 11 November 2002 / Received in final form 21 February 2003 Published online 11 April 2003
RID="a"
ID="a"e-mail: c.nappi@cib.na.cnr.it 相似文献
9.
X. L. Yu S. L. Ban 《The European Physical Journal B - Condensed Matter and Complex Systems》2006,52(4):483-491
The Larsen perturbation method is adopted to study the
influence of magnetic fields on polarons in realistic heterojunctions in a
quasi-two-dimension approximation. The interaction between an electron and
both the bulk longitudinal optical phonons and the two branches of interface
optical phonons is taken into account to show the influence of magnetic
fields at different ranges on the polaron cyclotron mass due to the coupling
of the electron with each branch of phonon modes. The result indicates that
not only do the bulk phonons influence the polaron cyclotron mass, but the
interface phonons do as well. The pressure effect on the cyclotron mass is
also discussed. 相似文献
10.
J. Tempere S.N. Klimin I.F. Silvera J.T. Devreese 《The European Physical Journal B - Condensed Matter and Complex Systems》2003,32(3):329-338
The properties of ripplonic polarons in a multielectron bubble in liquid helium are investigated on the basis of a path-integral
variational method. We find that the two-dimensional electron gas can form deep dimples in the helium surface, or ripplopolarons,
to solidify as a Wigner crystal. We derive the experimental conditions of temperature, pressure and number of electrons in
the bubble for this phase to be realized. This predicted state is distinct from the usual Wigner lattice of electrons: it
melts by dissociation of the ripplopolarons when the electrons shed their localizing dimple as the pressure on the multielectron
bubble drops below a critical value.
Received 20 February 2003 Published online 11 April 2003
RID="a"
ID="a"Also at: TU Eindhoven, Eindhoven, The Netherlands e-mail: devreese@uia.ua.ac.be 相似文献