Infrared nanoscopy on Si-doped GaAs-InGaAs core-shell nanowires


Infrared nanoscopy on Si-doped GaAs-InGaAs core-shell nanowires

Lang, D.; Balaghi, L.; Dimakis, E.; Hübner, R.; Kehr, S. C.; Eng, L. M.; Winnerl, S.; Schneider, H.; Helm, M.

We present nanoscopic studies on MBE-grown GaAs-InGaAs core-shell nanowires (NWs) with various Si-doped shells. For higher dopings and charge carrier densities, the plasmonic resonance shifts into the mid-infrared wavelength range, that can be fully probed using IR radiation from the FELBE free-electron laser source at the Helmholtz-Center Dresden-Rossendorf. Exploring these plasmonic resonance peaks at different wavelengths allows mapping the local charge carrier density and distribution along the NW with a high spatial resolution of better than 50 nm. Preliminary results using a CO2 laser scanned from 9.7-11.4 μm indicated the resonant behavior for the highest shell doping, in clear contrast to lower or undoped NWs. In the resonant case, the near-field (NF) emerging from the NW is strongly increased as compared to the substrate, in accordance with theory. The NF profiles of particular NWs show characteristic modifications at different wavelengths, which indicate an inhomogeneous distribution of the charge carrier density.

Keywords: FEL; mid-infrared; nanowires; near-field microscopy; plasmonics

Related publications

  • Poster
    WIRMS 2017 - 9th International Workshop on Infrared Microscopy and Spectroscopy with Accelerator Based Sources, 25.-28.09.2017, Oxford, United Kingdom
  • Lecture (Conference)
    DPG-Frühjahrstagung, 11.-16.03.2018, Berlin, Deutschland

Permalink: https://www.hzdr.de/publications/Publ-26851
Publ.-Id: 26851