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Article

Karel Král and Miroslav Menšík

In this work the experimental effect of a slow decay of the photoluminescence is studied theoretically in the case of quantum dots with an indirect energy band gap. The…

Abstract

In this work the experimental effect of a slow decay of the photoluminescence is studied theoretically in the case of quantum dots with an indirect energy band gap. The slow decay of the photoluminescence is considered as decay in time of the luminescence intensity, following the excitation of the quantum dot sample electronic system by a short optical pulse. In the presented theoretical treatment the process is studied as a single dot property. The inter-valley deformation potential interaction of the excited conduction band electrons with lattice vibrations is considered in the self-consistent Born approximation to the electronic self-energy. The theory is built on the non-equilibrium electronic quantum transport theory. The time dependence of the photoluminescence decay is estimated upon using a simple effective mass model. The numerical calculation of the considered model shows the power-law time characteristics of the photoluminescence decay in the long-time limit of the decay. We demonstrate that the nonadiabatic influence of the interaction of the conduction band electrons with the lattice vibrations provides a mechanism giving us the power-law time dependence of the photoluminescence intensity signal. This theoretical result emphasizes the role of the electron-phonon interaction in the nanostructures.

Details

World Journal of Engineering, vol. 11 no. 5
Type: Research Article
ISSN: 1708-5284

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Article

A. Majorana, O. Muscato and C. Milazzo

Time‐depending solutions to the Boltzmann‐Poisson system in one spatial dimension and three‐dimensional velocity space are obtained by using a recent finite difference…

Abstract

Time‐depending solutions to the Boltzmann‐Poisson system in one spatial dimension and three‐dimensional velocity space are obtained by using a recent finite difference numerical scheme. The collision operator of the Boltzmann equation models the scattering processes between electrons and phonons assumed in thermal equilibrium. The numerical solutions for bulk silicon and for a one‐dimensional n+‐n‐n+ silicon diode are compared with the Monte Carlo simulation. Further comparisons with the experimental data are shown.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 2
Type: Research Article
ISSN: 0332-1649

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Article

Orazio Muscato and Wolfgang Wagner

To provide an accurate analysis of the systematic error introduced by the constant time technique free flight mechanism, due to the choice of the time step and number particles.

Abstract

Purpose

To provide an accurate analysis of the systematic error introduced by the constant time technique free flight mechanism, due to the choice of the time step and number particles.

Design/methodology/approach

A homogeneous (bulk) silicon semiconductor is studied by using direct simulation Monte Carlo (DSMC).

Findings

The systematic error turns out to be of the first order with respect to the time step. The efficiency of the method is tackled.

Research limitations/implications

The analysis is limited to the bulk case. Future researches will consider non homogeneous devices

Originality/value

An accurate analysis of an “old” free flight mechanism has been performed, and its limits have been stated.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 24 no. 4
Type: Research Article
ISSN: 0332-1649

Keywords

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