Two-dimensional rare-earth silicide layers deposited on silicon substrates have been intensively investigated in the last decade, as they can be exploited both as Ohmic contacts or as photodetectors, depending on the substrate doping. In this study, we characterize rare-earth silicide layers on the Si(111) surface by a spectroscopic analysis. In detail, we combine Raman and reflectance anisotropy spectroscopy (RAS) with first-principles calculations in the framework of the density functional theory. RAS suggests a weakly isotropic surface, and Raman spectroscopy reveals the presence of surface localized phonons. Atomistic calculations allow to assign the detected Raman peaks to phonon modes localized at the silicide layer. The good agreement between the calculations and the measurements provides a strong argument for the employed structural model.

We report the first evidence of Raman scattering from surface phonons of a pristine metal surface. Our study reveals a Raman-active surface vibrational resonance on Cu(110) with a surprisingly large scattering efficiency. With the incident photon energy close to the energy of the Cu(110) surface state electronic transition, the Raman scattering from the surface optical resonance can be significantly enhanced, while any contribution from bulk phonons is absent.

N‐Heterocyclic carbenes (NHCs) are established ligands for various surfaces, known for their strong binding, ability to form self‐assembled monolayers, and modular structure. However, semiconductor surface modification with NHCs is still in its infancy despite its technological importance. Although previous studies focused on silicon, III‐V compound semiconductors offer direct bandgaps and high electron mobilities, making them ideal for (opto‐)electronics. This study examines the adsorption of different NHCs on GaAs, a prototypical III‐V material, using scanning tunneling microscopy, density functional theory, X‐ray photoelectron spectroscopy, low‐energy electron diffraction, and reflectance anisotropy spectroscopy. Covalent binding to the surface and the formation of well‐ordered NHC monolayers are observed, along with exceptionally large work function reductions. The unique structural features of NHCs enable precise control over film structure, ordering, and electronic properties.

The early growth stages of palladium (Pd) on Si(001) are studied in situ by reflectance anisotropy spectroscopy and Raman spectroscopy in ultrahigh vacuum. Two vicinal Si(001) samples with different degrees of surface ordering are investigated, revealing a distinct Volmer–Weber‐type growth behavior. Ex situ atomic force microscopy shows an inhomogeneous surface covered with islands on the less‐ordered substrate, while a complex layer with circular structures related to a nucleation‐controlled phase transition as previously reported is found on the well‐ordered sample. By Raman spectroscopy, a silicide‐like reacted phase at the Si–Pd interface is identified which is promoted by annealing up to 600 °C. The appearance of several additional phonon modes due to the interface reaction is in very good agreement with vibrational modes obtained from ab initio calculations for Pd incorporation into Si surface layers.