Interface Intermixing in Type II InAs/GaInAsSb Quantum Wells Designed for Active Regions of Mid-Infrared-Emitting Interband Cascade Lasers

• Published in: Nanoscale research letters 2015-12, Vol.10 (1), p.471-7, Article 471
• Main Authors: Motyka, Marcin, Sęk, Grzegorz, Ryczko, Krzysztof, Dyksik, Mateusz, Weih, Robert, Patriarche, Gilles, Misiewicz, Jan, Kamp, Martin, Höfling, Sven
• Format: Article
• Language: English
• Subjects: Cascade lasers; Chemistry and Materials Science; EMN Meeting; Image transmission; Indium arsenides; Materials Science; Mathematical analysis; Molecular Medicine; Nano Express; Nanochemistry; Nanoscale Science and Technology; Nanostructure; Nanotechnology; Nanotechnology and Microengineering; Optical transition; Quantum wells; Spectroscopy
• ISSN: 1931-7573; 1556-276X
• DOI: 10.1186/s11671-015-1183-x

The effect of interface intermixing in W-design GaSb/AlSb/InAs/Ga 0.665 In 0.335 As x Sb 1 − 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.