Impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of c-plane GaN/AlGaN quantum wells

We report on a combined theoretical and experimental study of the impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of c -plane GaN/AlGaN multi-quantum well systems. The presence of carrier localization effects in this system was demonstrated by experimental o...

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Bibliographic Details
Published in:Scientific reports 2019-12, Vol.9 (1), p.18862-18862, Article 18862
Main Authors: Roble, A. A., Patra, S. K., Massabuau, F., Frentrup, M., Leontiadou, M. A., Dawson, P., Kappers, M. J., Oliver, R. A., Graham, D. M., Schulz, S.
Format: Article
Language:English
Subjects:
639/301/1005
639/301/1019
639/301/1034
639/301/119
639/301/357
639/624
639/766
639/925
Fluctuations
Humanities and Social Sciences
Localization
multidisciplinary
Optical properties
Science
Science (multidisciplinary)
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Summary:We report on a combined theoretical and experimental study of the impact of alloy fluctuations and Coulomb effects on the electronic and optical properties of c -plane GaN/AlGaN multi-quantum well systems. The presence of carrier localization effects in this system was demonstrated by experimental observations, such as the “S-shape” temperature dependence of the photoluminescence (PL) peak energy, and non-exponential PL decay curves that varied across the PL spectra at 10 K. A three-dimensional modified continuum model, coupled with a self-consistent Hartree scheme, was employed to gain insight into the electronic and optical properties of the experimentally studied c -plane GaN/AlGaN quantum wells. This model confirmed the existence of strong hole localization arising from the combined effects of the built-in polarization field along the growth direction and the alloy fluctuations at the quantum well/barrier interface. However, for electrons these localization effects are less pronounced in comparison to the holes. Furthermore, our calculations show that the attractive Coulomb interaction between electron and hole results in exciton localization. This behavior is in contrast to the picture of independently localized electrons and holes, often used to explain the radiative recombination process in c -plane InGaN/GaN quantum well systems.
ISSN:2045-2322
2045-2322
DOI:10.1038/s41598-019-53693-2