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Analysis and optimasation of quantum cascade structures

Lindskog, Martin LU (2012) FYSM60 20121
Department of Physics
Mathematical Physics
Abstract
The quantum cascade laser (QCL) is a semiconductor heterostruc-
ture using inter sub-band transitions to generate stimulated emission.
The quantum cascade detector (QCD) is a similar to the QCL, but
the heterostructure is tailored to absorb radiation and give a read-out
current. In this work, three planned or realised QCL:s and two QCD:s
have been simulated and analysed using a program based on the non-
equilibrium Green’s function theory technique (NEGFT) and com-
paring to experimental measurements. The importance of electron-
electron scattering for thermalisation has been phenomenologically
studied by altering the barrier deformation potential and a planned
QCL has been optimised to give twice the gain from the original... (More)
The quantum cascade laser (QCL) is a semiconductor heterostruc-
ture using inter sub-band transitions to generate stimulated emission.
The quantum cascade detector (QCD) is a similar to the QCL, but
the heterostructure is tailored to absorb radiation and give a read-out
current. In this work, three planned or realised QCL:s and two QCD:s
have been simulated and analysed using a program based on the non-
equilibrium Green’s function theory technique (NEGFT) and com-
paring to experimental measurements. The importance of electron-
electron scattering for thermalisation has been phenomenologically
studied by altering the barrier deformation potential and a planned
QCL has been optimised to give twice the gain from the original struc-
ture. The work has involved corporations with experimental groups at
the National Research Council in Ottawa and the University of Wa-
terloo, Canada, which resulted in an article published in the Journal
of Applied Physics[1].
A new way to display the global behaviour of a QCL in terms of
carrier concentration and density of states, by using the spectral func-
tion has been developed. For the first time, a QCD has been simulated
by NEGFT to give space- and energy-resolved carrier concentrations,
density of states and energies of the electronic states.
The agreement of NEGFT simulations to experiment is also anal-
ysed. The model applies very well to many structures, but the lack of
electron-electron interaction causes problems with thermalisation for
some structures. (Less)
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author
Lindskog, Martin LU
supervisor
organization
course
FYSM60 20121
year
type
H2 - Master's Degree (Two Years)
subject
keywords
quantum cascade laser, QCL, quantum cascade detector, QCD, laser, Green's function theory, non-equilibrium, terahertz, solid state physics, optical gain, semiconductor, heterostructure
language
English
id
2543158
date added to LUP
2012-05-25 16:40:38
date last changed
2012-11-12 22:35:22
@misc{2543158,
  abstract     = {The quantum cascade laser (QCL) is a semiconductor heterostruc-
ture using inter sub-band transitions to generate stimulated emission.
The quantum cascade detector (QCD) is a similar to the QCL, but
the heterostructure is tailored to absorb radiation and give a read-out
current. In this work, three planned or realised QCL:s and two QCD:s
have been simulated and analysed using a program based on the non-
equilibrium Green’s function theory technique (NEGFT) and com-
paring to experimental measurements. The importance of electron-
electron scattering for thermalisation has been phenomenologically
studied by altering the barrier deformation potential and a planned
QCL has been optimised to give twice the gain from the original struc-
ture. The work has involved corporations with experimental groups at
the National Research Council in Ottawa and the University of Wa-
terloo, Canada, which resulted in an article published in the Journal
of Applied Physics[1].
A new way to display the global behaviour of a QCL in terms of
carrier concentration and density of states, by using the spectral func-
tion has been developed. For the first time, a QCD has been simulated
by NEGFT to give space- and energy-resolved carrier concentrations,
density of states and energies of the electronic states.
The agreement of NEGFT simulations to experiment is also anal-
ysed. The model applies very well to many structures, but the lack of
electron-electron interaction causes problems with thermalisation for
some structures.},
  author       = {Lindskog, Martin},
  keyword      = {quantum cascade laser,QCL,quantum cascade detector,QCD,laser,Green's function theory,non-equilibrium,terahertz,solid state physics,optical gain,semiconductor,heterostructure},
  language     = {eng},
  note         = {Student Paper},
  title        = {Analysis and optimasation of quantum cascade structures},
  year         = {2012},
}