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Electron Population Dynamics in Optically Pumped Asymmetric Coupled Ge/SiGe Quantum Wells: Experiment and Models
- Source :
- Photonics, Photonics, 7 (1), Photonics 7(2020)1, 2, Volume 7, Issue 1
- Publication Year :
- 2020
-
Abstract
- n-type doped Ge quantum wells with SiGe barriers represent a promising heterostructure system for the development of radiation emitters in the terahertz range such as electrically pumped quantum cascade lasers and optically pumped quantum fountain lasers. The nonpolar lattice of Ge and SiGe provides electron&ndash<br />phonon scattering rates that are one order of magnitude lower than polar GaAs. We have developed a self-consistent numerical energy-balance model based on a rate equation approach which includes inelastic and elastic inter- and intra-subband scattering events and takes into account a realistic two-dimensional electron gas distribution in all the subband states of the Ge/SiGe quantum wells by considering subband-dependent electronic temperatures and chemical potentials. This full-subband model is compared here to the standard discrete-energy-level model, in which the material parameters are limited to few input values (scattering rates and radiative cross sections). To provide an experimental case study, we have epitaxially grown samples consisting of two asymmetric coupled quantum wells forming a three-level system, which we optically pump with a free electron laser. The benchmark quantity selected for model testing purposes is the saturation intensity at the 1&rarr<br />3 intersubband transition. The numerical quantum model prediction is in reasonable agreement with the experiments and therefore outperforms the discrete-energy-level analytical model, of which the prediction of the saturation intensity is off by a factor 3.
- Subjects :
- Optical pumping
Materials science
Intersubband transitions
intersubband photoluminescence
Physics::Optics
02 engineering and technology
free electron laser
7. Clean energy
01 natural sciences
Molecular physics
Intersubband photoluminescence
silicon-germanium heterostructures
intersubband transitions
0103 physical sciences
electron–phonon interaction
Radiative transfer
Radiology, Nuclear Medicine and imaging
Physics::Atomic Physics
010306 general physics
infrared spectroscopy
Quantum wells
Terahertz quantum cascade laser
Electron–phonon interaction
Free electron laser
Silicon–germanium heterostructures
Infrared spectroscopy
Instrumentation
Quantum
silicon–germanium heterostructures
Quantum well
optical pumping
Settore FIS/03
Scattering
Heterojunction
terahertz quantum cascade laser
Rate equation
Electron-phonon interaction
Silicon-germanium heterostructures
021001 nanoscience & nanotechnology
Condensed Matter::Mesoscopic Systems and Quantum Hall Effect
Atomic and Molecular Physics, and Optics
quantum wells
electron-phonon interaction
Condensed Matter::Strongly Correlated Electrons
0210 nano-technology
Fermi gas
Subjects
Details
- ISSN :
- 23046732
- Database :
- OpenAIRE
- Journal :
- Photonics
- Accession number :
- edsair.doi.dedup.....c7f577f7d2a9a365122be425a113daeb
- Full Text :
- https://doi.org/10.3390/photonics7010002