نتایج جستجو برای: asymmetry quantum dot
تعداد نتایج: 343251 فیلتر نتایج به سال:
With attention to the thin film structure of colloidal quantum dot solar cells, in this paper in order to improvement of active layer absorption of them, we have proposed the use of nanostructure pattern for enhancement of their performance. For this purpose we have presented suitable nano hemisphare patterns in colloidal quantum dot solar cells for light trapping in absorption layer. Then with...
Lapses of transmission phase in transport through quantum dots are ubiquitous already in the absence of interaction, in which case their precise location is determined by the signs and magnitudes of the tunnelling matrix elements. However, actual measurements for a quantum dot embedded in an Aharonov-Bohm interferometer show systematic sequences of phase lapses separated by Coulomb peaks – an i...
We investigate the thermopower due to the orbital Kondo effect in a single quantum dot system by means of the noncrossing approximation. It is elucidated how the asymmetry of tunneling resonance due to the orbital Kondo effect affects the thermopower under gate-voltage and magnetic-field control.
We study optically single self-assembled quantum dots embedded within the wide quantum well of a mixed type quantum structure. We compare the steady state and pulsed photoluminescence spectra of these dots to those of previously studied " regular " dots. We unambiguously identify experimentally emission from various discrete charge state of the dots. We provide means for optically tune the char...
The design, operation and performance of quantum dot spin-polarized vertical cavity surface emitting lasers (VCSELs) and single-photon sources are described and discussed. The effects of spin-induced gain anisotropy on output polarization and threshold current reduction have been studied along with the high-frequency response in a spin-polarized VCSEL. While the output circular polarization in ...
We consider the system of an electronic quantum dot with a base set of discrete single-particle levels due to quantization effects in an arbitrarily given attractive potential. Intradot electron-electron interaction is described employing the full many-particle Coulomb interaction Hamiltonian in second quantization. Interaction effects arising from a capacitive response of the environment is in...
In this work, oscillator strength and quantum efficiency of new spherical GaN/AlGaN quantum dot was investigated. In order to obtain these parameters, at first, Schrödinger equation is solved in GaN/AlGaN spherical coordinate system in effective mass approximation, and energy level, wave function and transition matrix element of the parameter are obtained. The results show that oscillator stre...
We investigate the electronic transport through a single-level quantum-dot which is capacitively coupled to a charge-qubit. By employing the method of nonequilibrium Green's functions, we calculate the electric current through quantum dot at finite bias voltages. The Green's functions and self-energies of the system are calculated perturbatively and self-consistently to the second order of inte...
We show that electron and hole Landé g factors in self-assembled III-V quantum dots have a rich structure intermediate between that of paramagnetic atomic impurities and bulk semiconductors. Strain, dot geometry, and confinement energy modify the effective g factors, yet are insufficient to explain our results. We find that the dot's discrete energy spectrum quenches the orbital angular momentu...
We report on electrical transport measurements through a carbon nanotube quantum dot coupled to a normal and a superconducting lead. The ratio of Kondo temperature and superconducting gap TK/∆ is identified to govern the transport properties of the system. In the case of TK < ∆ the conductance resonance splits into two resonances at ±∆. For the opposite scenario TK > ∆ the conductance resonance...
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