National Repository of Grey Literature 53 records found  beginprevious29 - 38nextend  jump to record: Search took 0.01 seconds. 
Luminescence spectroscopy of two-dimensional quantum structures in GaAs/AlGaAs system
Grohoľová, Adela ; Grill, Roman (advisor) ; Oswald, Jiří (referee)
The aim of this work is the study of photoluminescence properties of GaAs/Al0.33Ga0.67As double quantum well. Low-temperature luminescence spectra of this sample are measured in dependence on electric and magnetic eld and dierent excitation power. The temperature dependencies of photoluminescence especially of the indirect excitons in in-plane magnetic eld are gauged as well. The simple model of localized indirect excitons is discussed to explain the discrepancy concerning the damping of indirect exciton photoluminescence in in-plane magnetic eld. The eective g-factors of indirect, neutral and charged excitons are calculated from observed Zeeman splitting. Few simple models are proposed to explain the behavior of eective g-factors. The possible agreement or contradiction with other published experimental data is discussed.
Luminescence of quantum dot heterostructures in applied electric field
Kubištová, Jana ; Zíková, Markéta ; Kuldová, Karla ; Pangrác, Jiří ; Hospodková, Alice ; Hulicius, Eduard ; Petříček, Otto ; Oswald, Jiří
In this work, photoluminescence (PL) and electroluminescence (EL) of samples with InAs/GaAs quantum dots were measured with electric voltage or current applied on the structure. The EL structures emitting at 1300 nm were prepared by using n-type substrate. By applying the electric voltage in reverse bias on the sample, the evinced PL may be switched off - it decreases rapidly with the applied voltage and is negligible at about 10 V. Such structures which PL intensity is tunable by applied voltage have a broad spectrum of applications in optoelectronics.
GaAsSb strain reducing layer covering InAs/GaAs quantum dots
Zíková, Markéta ; Hospodková, Alice ; Pangrác, Jiří ; Oswald, Jiří ; Kubištová, Jana ; Hulicius, Eduard ; Komninou, Ph. ; Kioseoglou, J. ; Nikitis, F.
GaAsSb is often used as a capping material for InAs quantum dots (QDs) due to its suitable conduction band alignment and suppression of In segregation from QDs during the capping process.We have found out that during the GaAsSb layer growth, Sb atoms segregate above InAs QDs, which is proved by the AFM and HRTEM measurements. For higher amount of Sb in GaAsSb, the measured photoluminescence (PL) has longer wavelength, but if it is too high, the structure may become type II with decreased PL intensity. For thick GaAsSb layer, the PL intensity decreases, because only big QDs participate to the PL.
In situ monitorování růstu MOVPE InAs/GaAs struktur s kvantovými tečkami pomocí reflektanční anisotropické
Vyskočil, Jan ; Hospodková, Alice ; Pangrác, Jiří ; Melichar, Karel ; Oswald, Jiří ; Kuldová, Karla ; Mates, Tomáš ; Šimeček, Tomislav ; Hulicius, Eduard
Reflectance anisotropy spectroscopy (RAS) has been used for the real-time observation and optimization of single and double InAs/GaAs quantum dot layer structure growth. The properties of samples were ex situ characterized by photoluminescence and AFM.
Studie InAs/GaAs kvantových teček vypěstovaných technologií LP-MOVPE
Hazdra, P. ; Atef, M. ; Komarnitsky, V. ; Oswald, Jiří ; Kuldová, Karla ; Hulicius, Eduard
We show simulation study of electronic transition energy for InAs/GaAs quantum dots fabricated with LP-MOVPE. The simulation results were compared with experimental data obtained by AFM and photoluminescence.

National Repository of Grey Literature : 53 records found   beginprevious29 - 38nextend  jump to record:
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1 Oswald, Jaroslav
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