https://doi.org/10.1140/epjp/s13360-026-07438-6
Regular Article
Optical absorption and photoionization cross section of exciton in multilayer cylindrical quantum dots
1
OAPM Group, Laboratory of Materials, Waves, Energy and Environment, Department of Physics, Faculty of Sciences, University Mohamed I, 60000, Oujda, Morocco
2
LRDSI, Department of Physics, Al-Hoceima Faculty of Science and Technology, Abdelmalek Essaadi University, Tétouan, Morocco
3
Laboratory of Innovation in Science, Technology and Education, CRMEF, 60000, Oujda, Morocco
4
Research Laboratory in Sciences and Techniques, ESEFA, Ibnou Zohr University, 80000, Agadir, Morocco
5
Grupo de Materia Condensada-UdeA, Instituto de Física, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia
6
ESEFA, Ibnou Zohr University, 80000, Agadir, Morocco
a
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Received:
5
August
2025
Accepted:
12
February
2026
Published online:
27
February
2026
Abstract
We present a systematic theoretical investigation of excitonic optical properties in multilayer cylindrical quantum dots (MCQDs) based on GaAs and GaN, focusing simultaneously on two rarely combined quantities: the interband optical absorption coefficient, evaluated both with and without electron–hole Coulomb interaction, as well as on the photoionization cross section (PCS). Within the effective mass approximation and using Coulomb-correlated variational wavefunctions, we quantify how the core radius (
) and height (H) jointly tune bound and unbound excitonic transitions and the associated ionization threshold. The results reveal several non-trivial excitonic signatures that go beyond standard quantum confinement trends: (i) the energy splitting between the bound and unbound absorption peaks, equal to the exciton binding energy, displays strong material and geometric dependence, reaching 
meV in GaN-MCQDs and 
meV in GaAs-MCQDs under comparable confinement; (ii) the PCS resonance coincides exactly with this binding energy and shifts predictably with and H, providing a quantitative design rule for UV-range excitonic photodetectors; (iii) despite their smaller volumes, GaN-MCQDs exhibit 5–10 times higher absorption amplitudes than GaAs structures, highlighting their superior potential for high-energy optoelectronic applications. These results deliver actionable physical insights into Coulomb-driven excitonic processes in multilayer cylindrical nanostructures and establish design guidelines for geometry-tunable, stable excitonic devices operating from the infrared to the deep-ultraviolet.
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© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
