332 research outputs found
Electron Scattering and Hybrid Phonons in Low Dimensional Laser Structures made with GaAs/AlxGa1-xAs
We theoretically and numerically present the hybrid phonon modes for the
double heterostructure GaAs/AlxGa1-xAs and their interactions with electrons.
More specifically, we have calculated the electron capture within a symmetric
quantum well via the emission of hybrid phonons. Our investigation shows that
the capture rates via the hybrid phonons are matched to the rates predicted by
the dielectric continuum (DC) model and the concentration of aluminium which is
an important parameter for controlling the electron capture process in light
emitting diodes (LED).Comment: 11 page
Surface scattering velocities in III-nitride quantum well laser structures via the emission of hybrid phonons
We have theoretically and numerically studied nitride-based quantum well (QW)
laser structures. More specifically, we have used a QW made with III-nitride
where the width of the barrier region is large relative to the electron mean
free path, and we have calculated the electron surface capture velocities by
considering an electron flux which is captured into the well region. The
process is assisted by the emission of the longitudinal optical phonons as
predicted by the hybrid (HB) model. The results of surface capture velocities
via the emission of HB phonons are compared to the emission of the dielectric
continuum phonons (Zakhleniuk et al 1999 Phys. Status Solidi a 176 79). Our
investigation shows that the two different phonon models predict almost the
same results for the non-retarded limit. Furthermore, the surface capture
velocities strongly depend on the size of the structure and the heterostructure
materials. Lastly, a comparison to the recent experimental values shows that
our model could accurately describe the experimentally measured parameters of
the quantum capture processes
Suppression of electron relaxation and dephasing rates in quantum dots caused by external magnetic fields
An external magnetic field has been applied in laterally coupled dots (QDs)
and we have studied the QD properties related to charge decoherence. The
significance of the applied magnetic field to the suppression of
electron-phonon relaxation and dephasing rates has been explored. The coupled
QDs have been studied by varing the magnetic field and the interdot distance as
other system parameters. Our numerical results show that the electron
scattering rates are strongly dependent on the applied external magnetic field
and the details of the double QD configuration.Comment: 13 pages, 6 figure
Exiting the risk assessment maze: A meta-survey
Organizations are exposed to threats that increase the risk factor of their ICT systems. The assurance of
their protection is crucial, as their reliance on information technology is a continuing challenge for both
security experts and chief executives. As risk assessment could be a necessary process in an organization,
one of its deliverables could be utilized in addressing threats and thus facilitate the development of a security
strategy. Given the large number of heterogeneous methods and risk assessment tools that exist, comparison
criteria can provide better understanding of their options and characteristics and facilitate the selection of
a method that best fits an organization’s needs. This paper aims to address the problem of selecting an
appropriate risk assessment method to assess and manage information security risks, by proposing a set of
comparison criteria, grouped into 4 categories. Based upon them, it provides a comparison of the 10 popular
risk assessment methods that could be utilized by organizations to determine the method that is more
suitable for their needs. Finally, a case study is presented to demonstrate the selection of a method based
on the proposed criteri
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