Seminarium "Coherence-Correlations-Complexity" (KFT, PWr)
Sala 320a bud. A-1, Politechnika Wrocławska
Carrier and spin relaxation in self-assembled semiconductor quantum structures with atypical quasi-0D quantum confinement
dr Marcin Syperek
Katedra Fizyki Doświadczalnej WPPT PWr
During the lecture I am going to present experimental work concerning carrier and spin relaxation in self-assembled semiconductor quantum structures. In particular I will concentrate the focus on quantum dots strongly elongated in one of the spatial direction, devoted for photon sources in the near infrared spectral range (1.3-1.55 mm) and hybrid structures, where quantum dots are coupled to a quantum well through a thin potential barrier. Today and future optoelectronic devices can benefit from theoretically predicted advantages of these systems. However, there is still lack of experimental as well as theoretical data which can provide sufficient understanding of physical processes which occur in there.
In the first part of my talk, I am going to show results from the time-resolved photoluminescence experiment that directly gives information about the e-h lifetime on the ground state of an InAs/InP(001) quantum dot and give some initial idea how to connect the e-h recombination lifetime to a carrier confinement limit in a quasi-0D system. I will present also results of pump-probe reflection experiment on InAs/InP(001) quantum dots that provide essential information about intraband carrier relaxation processes, including possible relaxation scenario which can be typical for investigated QD system. Finally, I will conclude this part of my talk by presenting an initial experimental data on spin relaxation process.
In the second part of my presentation, I am going to show carrier relaxation process on the ground state of a coupled InGaAs/GaAs quantum well-quantum dots system and explain peculiar behaviour of the e-h lifetime. This part of my talk I will conclude by presenting initial data related to longitudinal phonon assisted spin initialization and further exciton spin relaxation on the ground state of a strongly coupled system.
