title: Interface Intermixing in Type II InAs/GaInAsSb Quantum Wells Designed for Active Regions of Mid-Infrared-Emitting Interband Cascade Lasers.
abstract: The effect of interface intermixing in W-design GaSb/AlSb/InAs/Ga0.665In0.335AsxSb1 - x/InAs/AlSb/GaSb quantum wells (QWs) has been investigated by means of optical spectroscopy supported by structural data and by band structure calculations. The fundamental optical transition has been detected at room temperature through photoluminescence and photoreflectance measurements and appeared to be blueshifted with increasing As content of the GaInAsSb layer, in contrast to the energy-gap-driven shifts calculated for an ideally rectangular QW profile. The arsenic incorporation into the hole-confining layer affects the material and optical structure also altering the InAs/GaInAsSb interfaces and their degree of intermixing. Based on the analysis of cross-sectional transmission electron microscopy images and energy-dispersive X-ray spectroscopy, we could deduce the composition distribution across the QW layers and hence simulate more realistic confinement potential profiles. For such smoothed interfaces that indicate As-enhanced intermixing, the energy level calculations have been able to reproduce the experimentally obtained trend.
authors.affiliation: Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, Wrocław, Poland. marcin.motyka@pwr.edu.pl.
authors.forename: Marcin
authors.initials: M
authors.lastname: Motyka
authors.affiliation: Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, Wrocław, Poland.
authors.forename: Grzegorz
authors.initials: G
authors.lastname: Sęk
authors.affiliation: Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, Wrocław, Poland.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Ryczko
authors.affiliation: Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, Wrocław, Poland.
authors.forename: Mateusz
authors.initials: M
authors.lastname: Dyksik
authors.affiliation: Technische Physik and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Robert
authors.initials: R
authors.lastname: Weih
authors.affiliation: Laboratoire de Photonique et de Nanostructures, CNRS, Université Paris-Saclay, Route de Nozay, 91460, Marcoussis, France.
authors.forename: Gilles
authors.initials: G
authors.lastname: Patriarche
authors.affiliation: Laboratory for Optical Spectroscopy of Nanostructures, Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Technology, Wybrzeże Wyspiańskiego 27, Wrocław, Poland.
authors.forename: Jan
authors.initials: J
authors.lastname: Misiewicz
authors.affiliation: Technische Physik and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Kamp
authors.affiliation: Technische Physik and Wilhelm-Conrad-Röntgen-Research Center for Complex Material Systems, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.|School of Physics and Astronomy, University of St. Andrews, North Haugh, KY16 9SS, St. Andrews, UK.
authors.forename: Sven
authors.initials: S
authors.lastname: Höfling
keywords: EDX spectra; FTIR spectroscopy; Interband cascade lasers; Intermixing; QW interface profile; Type II GaIn(As)Sb/GaSb