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Cathodoluminescence Spectroscopy of Silicon Nanoparticles

  • The fabrication of nanostructures with ever-decreasing sizes has increased the demand of suitable characterization methods which allow to determine their shape and size at the true nanoscale, and similarly important, enable the investigation of their optical properties beyond the diffraction limit. Due to its high spectral and spatial resolution down to the (sub-) nanometer range, electron beam-based techniques, namely cathodoluminescence (CL) has become a powerful characterization tool, particularly to study plasmonic and dielectric nanostructures. However, the interpretation of the resulting spectral CL maps is not always unambiguously straightforward. In this work, Mie resonances in single Si nanospheres of different sizes have been systematically studied, using experimental CL spectroscopy and an analytical CL model. For smaller spheres (r ~ 75 nm), the eigenmodes can be unequivocally identified, with relative changes in intensity of the electric and magnetic dipole depending onThe fabrication of nanostructures with ever-decreasing sizes has increased the demand of suitable characterization methods which allow to determine their shape and size at the true nanoscale, and similarly important, enable the investigation of their optical properties beyond the diffraction limit. Due to its high spectral and spatial resolution down to the (sub-) nanometer range, electron beam-based techniques, namely cathodoluminescence (CL) has become a powerful characterization tool, particularly to study plasmonic and dielectric nanostructures. However, the interpretation of the resulting spectral CL maps is not always unambiguously straightforward. In this work, Mie resonances in single Si nanospheres of different sizes have been systematically studied, using experimental CL spectroscopy and an analytical CL model. For smaller spheres (r ~ 75 nm), the eigenmodes can be unequivocally identified, with relative changes in intensity of the electric and magnetic dipole depending on the electron beam position within the sphere. However, in larger spheres (r ~ 105 nm), the modal assignment becomes increasingly difficult due to a larger number of Mie modes in the visible spectral range. Additionally, penetrating electron beams generate two radiating dipoles at the two Si interfaces – due to the electron and its image charge collapsing at those interfaces – which can, depending on the electron beam’s velocity and its path length inside the particle, produce distinct resonances or dips (constructive or destructive interference of those two radiative dipoles). It is demonstrated that superimposed on the eigenmodes of the studied nanospheres, these resonances can distort the recorded spectrum and lead to potentially erroneous assignment of modal characters to the spectral features. An intuitive analogy is developed to unambiguously distinguish those resonance induced by transition radiation from the nanoparticle-specific Mie resonances.zeige mehrzeige weniger

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Autor*innen:Saskia FiedlerORCiD
Koautor*innen:E.P. Stamatopoulou, A. Assadillayev, C. Wolff, H. Sugimoto, M. Fuji, N.A. Mortensen, S. Raza, C. Tserkezis
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2022
Organisationseinheit der BAM:1 Analytische Chemie; Referenzmaterialien
1 Analytische Chemie; Referenzmaterialien / 1.2 Biophotonik
DDC-Klassifikation:Naturwissenschaften und Mathematik / Chemie / Analytische Chemie
Freie Schlagwörter:Cathodoluminescence; Mie resonances; Silicon nanoparticles
Themenfelder/Aktivitätsfelder der BAM:Chemie und Prozesstechnik
Veranstaltung:Optoelectronic Processes at Nanostructured Interfaces 2022
Veranstaltungsort:Bad Honnef, Germany
Beginndatum der Veranstaltung:21.03.2022
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:23.03.2022
Referierte Publikation:Nein
Eingeladener Vortrag:Nein
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