نتایج جستجو برای: miniband engineering
تعداد نتایج: 262819 فیلتر نتایج به سال:
Electron and hole states are studied in quantum well wires (QWWs) with a rectangular cross section. A theoretical approach is developed, within which the electronic properties of a single QWW as well as of finite and infinite planar lattices of QWWs are analysed. It is demonstrated that the ratio of effective masses in the well and in the barrier influences the dispersion law of the electron mo...
The transport of electrons in a semiconductor superlattice miniband under the influence of electrical and magnetic fields, which are applied in different directions on the superlattice, is investigated. The time series diagrams and the Lyapunov exponent are computed using the fourth-order Runge-Kutta method. The numerical computations show that for particular values of the parameters, which dep...
In a multimode photonic-crystal waveguide, we observe strong enhancement of the photoluminescence of embedded quantum dots at the edges of the so-called mini-stopband that were opened by Bragg diffraction between two guided modes. Taking into account light collection, we relate this observation to the singular photon density of states that is characteristic of a one-dimensional photon system. F...
A general theoretical framework for the modelling of miniband transport in semiconductor nanostructures under broadband illumination is presented. Our approach is based on the multi-subband three-dimensional Boltzmann transport equation and allows to investigate both the steady-state and the time-dependent dynamics. The model has been succesfully applied to the problem of the design and optimiz...
Charge transport in nanosized electronic systems is described by semiclassical or quantum kinetic equations that are often costly to solve numerically and difficult to reduce systematically to macroscopic balance equations for densities, currents, temperatures and other moments of macroscopic variables. The maximum entropy principle can be used to close the system of equations for the moments b...
Electric transport in semiconductor superlattices is dominated by pronounced negative differential conductivity. In this report the standard transport theories for superlattices, i.e. miniband conduction, Wannier-Stark-hopping, and sequential tunneling, are reviewed in detail. Their relation to each other is clarified by a comparison with a quantum transport model based on nonequilibrium Green ...
We present the first numerical solutions of a kinetic theory description of selfsustained current oscillations in n-doped semiconductor superlattices. The governing equation is a single-miniband Boltzmann-Poisson transport equation with a BGK (Bhatnagar-Gross-Krook) collision term. Appropriate boundary conditions for the distribution function describe electron injection in the contact regions. ...
The observation of the quantum Hall effect in an electronic system does not depend on the strict two-dimensionality of the system, but rather that the conductivity in the direction of the magnetic field (ozz) vanishes. This condition can be acheived in a superlattice when the Landau level spacing exceeds the zero-field miniband width of the superlattice. It is now possible to test this criterio...
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