Plasmon resonances in silicon quantum wires

Silicon nanowires (SiNWs) have represented the subject of an extensive literature since decades now. Their fascinating physical properties and their many applications in diverse field of technology - from the energy production, conversion, and storage to the sensing, photovoltaics and catalysis - make them interesting both scientifically and industrially. Some of their properties however, although intriguing, are still not deeply investigated for the difficulties related to the limits of the standard characterization techniques, and for the difficulty to interpret the experimental data. When irradiated with an electromagnetic radiation at a certain frequency the valence electrons inside the SiNW start to collectively oscillate in phase, generating the plasmonic resonances (PR). In literature discrete patterns of the PRs in SiNWs, have been mainly observed by electron energy loss spectroscopy and in structures as large as 100 nm. Thanks to the use of a cutting-edge technique based on the use of a high-resolution STEM coupled with EELS in situ, recently they have also been directly observed in SiNWs as small as 30 nm [1]. To deeply understand the plasmonic resonance in such small nanostructures and fully interpret their experimental behaviour, the work has been supported by numerical simulations on the optical dispersion data. In this talk, we will present the results of this investigation compared with new data obtained by changing SiNW sizes.

[1]: Borgh, G., Bongiorno, C., La Magna, A., Mannino, G., Patanè, S., Adam, J., & Puglisi, R. A. (2021). Surface plasmons in silicon nanowires. Advanced Photonics Research, 2(12), [202100130]. https://doi.org/10.1002/adpr.202100130