Analysis and optimasation of quantum cascade structures
(2012) FYSM60 20121Department 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)
Please use this url to cite or link to this publication:
http://lup.lub.lu.se/student-papers/record/2543158
- author
- Lindskog, Martin LU
- supervisor
- organization
- course
- FYSM60 20121
- year
- 2012
- 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}}, language = {{eng}}, note = {{Student Paper}}, title = {{Analysis and optimasation of quantum cascade structures}}, year = {{2012}}, }