Surface, interfaces, thin films

Finding the wedge-shaped Au nanoclusters at the surface of GaAs and investigating them with the polarization spectroscopy of plasmons

V. L. Berkovits^a, V. A. Kosobukin^a, V. P. Ulin^a, P. A. Alekseev^a, F. Yu. Soldatenkov^a, A. V. Nashchekin^a, S. A. Khakhulin^b, O. S. Komkov<sup>b

a</sup> Ioffe Institute, 194021 St. Petersburg, Russia
^b Saint Petersburg Electrotechnical University "LETI", 197376 St. Petersburg, Russia

Abstract: Using high-temperature annealing of thin gold nanofilms deposited onto the (001) surface of doped $p$-GaAs crystal with an ultrathin oxide layer, the nanoclusters of gold (Au$_2$Ga alloy) are fabricated. The gold clusters have the wedge shapes with rectangular bases elongated in [110] direction at GaAs(001) surface. This assertion is confirmed by the data of diagnostics of Au/$p$-GaAs(001) structures. Anisotropic plasmons localized on equally oriented wedge-shaped Au (Au$_2$Ga) clusters are investigated with the optical reflectance anisotropy spectroscopy and spectroscopy of polarized light reflection. It is shown that the spectral peak at the energy about 0.9 eV in the near infrared range is associated with plasmons polarized along the longest sides of clusters in crystallographic direction [110]. Another peak – at the energy of 1.8 eV – is due to plasmons having polarization in direction $[1\bar10]$.

Keywords: Au-GaAs interaction, wedge-shaped Au clusters, anisotropic plasmons, polarization spectroscopy.

Received: 18.05.2023
Revised: 21.08.2023
Accepted: 25.08.2023

DOI: 10.61011/FTP.2023.06.56478.5188

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