Electromagnetic Response of Metal-Semiconductor-Oxide Particles in the Near-Infrared Regime

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School of Science | Doctoral thesis (article-based) | Defence date: 2023-03-24
Degree programme
94 + app. 90
Aalto University publication series DOCTORAL THESES, 30/2023
Plasmonics is a study of how electromagnetic radiation is coupled to free-carrier systems within the bulk of the material or at boundaries between different materials. Localized surface plasmon resonances (LSPRs) are caused by coherent oscillations of conduction electrons near the surface of metals which lead to an increase in the optical response. In this thesis, we study the electromagnetic response of spherical and spheroidal metal, dielectric, and semiconducting microparticles and nanoparticles. The aim is to predict the optical properties of single particles and coating containing the particles at low volume fraction in the visible and infrared regime using computational methods. The methods that we use include Lorenz-Mie theory, the quasistatic approximation, surface integral equation (SIE) technique, and a Monte Carlo method. In the first part, we study the optical properties of spherical core@shell particles consisting of metallic and semiconductor layers. The results of a particle with a metallic core and a semiconductor shell show shifting and merging of the LSPR from the metallic core and Mie resonances from the semiconductor shell for different particle sizes. We also consider the reverse configuration in which the shell is a metal, and the core is a semiconductor. The plasmon modes from the metallic shell are influenced by the particle sizes, the permittivity of the surrounding core and the medium. These core@shell nanoparticles show sufficiently high and robust efficiencies for photovoltaic applications and catalysis.In the second part, we study the optical properties of unconventional semiconductor particles. We choose copper antimony disulfide, CuSbS2, as a material that can improve the optical properties as compared to conventional semiconductors. Our results demonstrate that as the spherical CuSbS2 particle size increases, the absorption and the total scattering efficiencies broaden and shift to longer wavelengths. CuSbS2 exhibits high absorption coefficients and a band gap compatible with solar radiation, making it an excellent candidate for use in nanocrystalline solar cells and other NIR devices. The results for non-spherical particles for different shapes and orientations exhibit significant differences in their electromagnetic response. Interestingly, thin spheroids exhibit a strong plasmonic resonance in some cases. Decreasing the length of the short axis of the spheroids leads to Fano resonances in the near-infrared regimes. The presence and spectral position of plasmonic and Fano peaks are tunable as a function of the orientation and size of the spheroid. As a final step, we examine the optical properties of a layer containing CuSbS2 particles using Monte Carlo method. Monte Carlo method is in conjunction with Lorenz-Mie theory or SIE technique for modelling radiation transport in a layer. Anisotropic shapes can exhibit significant changes in optical properties depending on their particle orientation within a layer. Our study confirms that the optical properties of the layer such as absorbance, transmittance and reflectance of layer containing anisotropic particles can be tuned by the orientation of the particle.
Supervising professor
Ala-Nissilä, Tapio, Prof., Aalto University, Department of Applied Physics , Finland
Thesis advisor
Conley, Kevin, Dr., Aalto University, Finland
plasmonic, Lorenz-Mie theory, Monte Carlo, electromagnetic response
Other note
  • [Publication 1]: Seyedheydari, Fahime and Conley, Kevin M and Thakore, Vaibhav and Karttunen, Mikko and Sihvola, Ari and Ala-Nissila, Tapio. Electromagnetic response of nanoparticles with a metallic core and a semiconductor shell. Journal of Physics Communications, vol. 5, p. 015002, January 2021.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202102021865
    DOI: 10.1088/2399-6528/abd4c4 View at publisher
  • [Publication 2]: Seyedheydari, Fahime and Conley, Kevin and Ala-Nissila, Tapio. Scattering by core-shell semiconductor microinclusions for plasmonically enhanced near-IR applications. In International Conference on Metamaterials, Photonic Crystals and Plasmonics (META), Lisbon Portugal, July 2019
  • [Publication 3]: Seyedheydari, Fahime and Conley, Kevin and Ala-Nissila, Tapio. Near-IR plasmons in micro and nanoparticles with a semiconductor core. Photonics, vol. 7, p. 10, January 2020.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202004032733
    DOI: 10.3390/photonics7010010 View at publisher
  • [Publication 4]: Conley, Kevin M and Thakore, Vaibhav and Seyedheydari, Fahime and Karttunen, Mikko and Ala-Nissila, Tapio. Directing near-infrared photon transport with core-shell particles. AIP Advances, vol. 7, p. 095128, September 2020.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202010306194
    DOI: 10.1063/5.0015553 View at publisher
  • [Publication 5]: Seyedheydari, Fahime and Conley, Kevin and Ylä-Oijala, Pasi and Sihvola, Ari and Ala-Nissila, Tapio. Electromagnetic Response and Optical Properties of Spherical CuSbS2 Nanoparticles. In Photonics and Electromagnetics Research Symposium (PIERS), Hangzhou China, November 2021. Full text in Acrsi/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202204062756.
    DOI: 10.1109/PIERS53385.2021.9694781 View at publisher
  • [Publication 6]: Seyedheydari, Fahime and Conley, Kevin and Ylä-Oijala, Pasi and Sihvola, Ari and Ala-Nissila, Tapio. Electromagnetic Response and Optical Properties of Anisotropic CuSbS2 Nanoparticles. Journal of The Optical Society of America B, vol. 39, p. 1743, July 2022.
    Full text in Acris/Aaltodoc: http://urn.fi/URN:NBN:fi:aalto-202208245004
    DOI: 10.1364/JOSAB.456468 View at publisher