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Published on: August 2, 2019
Carrier dynamics in type-II GaAsSb/GaAs quantum wells
M Baranowski1, M Syperek, R Kudrawiec
1Institute of Physics, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland. michal.baranowski@pwr.wroc.pl
Summary
This study reveals dynamic band bending in type-II GaAsSb/GaAs quantum wells, influencing photoluminescence (PL) kinetics. Charge transfer processes critically affect PL decay, with temperature modulating these effects.
Area of Science:
- Semiconductor Physics
- Materials Science
- Optoelectronics
Background:
- Type-II semiconductor heterostructures, such as GaAsSb/GaAs quantum wells, exhibit unique electronic and optical properties due to spatially separated charge carriers.
- Understanding photoluminescence (PL) kinetics in these systems is crucial for developing advanced optoelectronic devices.
Purpose of the Study:
- To investigate the time-resolved photoluminescence (PL) characteristics of type-II GaAsSb/GaAs quantum wells.
- To elucidate the roles of dynamic band bending and localized centers in governing PL kinetics.
- To explore the influence of temperature on charge transfer processes and their impact on PL decay.
Main Methods:
- Time-resolved photoluminescence (PL) spectroscopy was employed to measure PL kinetics.
- Analysis involved considering dynamic band bending effects due to evolving electron and hole distributions.
- A three-level rate equation model was developed to interpret the observed phenomena.
Main Results:
- Dynamic band bending, dependent on optical pump power, causes temporal renormalization of quantum well energy and alters oscillator strength.
- The measured PL lifetime was determined to be 4.5 ns.
- Charge transfer processes between the quantum well and localized centers significantly impact PL decay, with temperature-dependent back transfer influencing kinetics.
Conclusions:
- Dynamic band bending and charge transfer are key factors controlling PL kinetics in type-II GaAsSb/GaAs quantum wells.
- Temperature plays a critical role in modulating charge transfer, affecting PL decay rates.
- The proposed three-level rate equation model successfully explains the observed temperature-dependent PL behavior.
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