Dresden 2020 – scientific programme

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O: Fachverband Oberflächenphysik

O 43: Plasmonics and Nanooptics III: Periodic Structures and Theory

O 43.11: Talk

Tuesday, March 17, 2020, 13:00–13:15, WIL A317

Tuning the coupling of plasmonic structures with photonic crystals — •Rahim Benrali, Constance Schmidt, Teresa I. Madeira, and Dietrich R. T. Zahn — Semiconductor Physics, Chemnitz University of Technology, D-09107 , Germany

One-dimensional photonic crystals (PCs) are multilayered stacks with alternating refractive index (RI) and layer thicknesses (LT). PCs show a high reflectivity in a broad spectral range known as photonic bandgap (PBG). It was already shown that coupling of PCs with metallic nanoparticles (MNPs) in a photonic crystal plasmonic hybrid system (PCPHS) provides new ways of controlling and enhancing the optical response of plasmonic resonances [1]. Here we investigate the coupling of PCs with MNPs and the effect of tuning the PBG over the visible spectral range. PCs were prepared by electrochemical etching of p-doped silicon with hydrofluoric acid (HF), resulting in porous silicon (PS). MNPs show a plasmonic behaviour, known as localized surface plasmonic resonance (LSPR). The LSPR depends mainly on the metal and the geometry of the MNPs. Here triangular MNPs were obtained by nanosphere lithography (NSL). We used spectroscopic ellipsometry to investigate the effects of etching time and current density on PS. Furthermore, different parameters to influence the PBG (LT, RI, interface roughness) were investigated. Raman spectroscopy was used to test the performance of the PCPHS. The impact on the intensity of the Raman signal due to the PCPHS is demonstrated using organic molecules as Raman probes. [1] M. Fränzl, S. Moras, O. D. Gordan, D. R. T. Zahn, J. Phys. Chem. C 2018, 122, 18, 10153-10158