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Main Title: Carrier Dynamics in Al‐Rich AlGaN/AlN Quantum Well Structures Governed by Carrier Localization
Author(s): Frankerl, Christian
Nippert, Felix
Hoffmann, Marc Patrick
Brandl, Christian
Lugauer, Hans-Jürgen
Zeisel, Roland
Hoffmann, Axel
Davies, Matthew John
Type: Article
Language Code: en
Abstract: The carrier dynamics of Al‐rich AlGaN/AlN quantum well (QW) structures in the presence of strong carrier localization is reported. Excitation density‐dependent photoluminescence (PL) measurements at low temperatures reveal a clear correlation between the onset of efficiency droop and the broadening of the time‐integrated PL spectra. While the droop onset is heavily impacted by the localization strength, the PL emission broadening is observed almost exclusively on the high energy side of the emission spectrum. Spectrally resolved PL decay transient measurements reveal a strong dependency of the carrier lifetimes on the emission photon energy across the spectrum, consistent with a distribution of localized states, as well as on the temperature, depending on the localization strength of the investigated structure. The characteristic “S”‐shaped temperature dependence of the PL emission energy is shown to be directly correlated to the thermal redistribution of carriers between localized states. Based on these findings, the role of carrier localization in the recombination processes in AlGaN QW structures is underlined and its implications for efficiency droop are discussed.
Issue Date: 7-Aug-2020
Date Available: 17-Dec-2020
DDC Class: 530 Physik
Subject(s): AlGaN
carrier localization
carrier redistribution
efficiency droops
quantum wells
time-resolved photoluminescence
Sponsor/Funder: TU Berlin, Open-Access-Mittel – 2020
BMBF, 03ZZ0134A, Zwanzig20 - Advanced UV for Life - Verbundvorhaben: UV Power; TP1: Entwicklung von UVC Hochleistungsleuchtdioden um 280 nm
DFG, 43659573, SFB 787: Halbleiter - Nanophotonik: Materialien, Modelle, Bauelemente
Journal Title: physica status solidi (b)
Publisher: Wiley
Publisher Place: New York, NY
Volume: 257
Issue: 12
Article Number: 2000242
Publisher DOI: 10.1002/pssb.202000242
EISSN: 1521-3951
ISSN: 0370-1972
Appears in Collections:Inst. Festkörperphysik » Publications

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