Size-dependent plasmon effects in periodic W-Si- based mirrors, investigated by X-ray photoelectron spectroscopy

• Published in: Applied surface science Vol. 566; p. 150616
• Main Authors: Kozakov, Alexey T., Kumar, Niranjan, Garakhin, Sergei A., Polkovnikov, Vladimir N., Chkhalo, Nikolay I., Nikolskii, Anatoly V., Scrjabin, Anton A., Nezhdanov, Aleksey V., Yunin, Pavel A.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.11.2021
• Subjects: Multilayer mirrors; Reflectivity of mirrors; Volume and surface plasmons; X-ray photoelectron spectroscopy; Reflectivity of mirrors; Volume and surface plasmons; Multilayer mirrors; X-ray photoelectron spectroscopy
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2021.150616

Multilayer mirrors operating at extreme ultraviolet and soft x-ray wavelengths were fabricated by dc magnetron sputtering, which showed a strong dependence of reflection coefficient with β (ratio of W layer to multilayer period, dp) and plasmon excitation. The reflection coefficient was higher for the lower value of plasmon intensity in multilayers. [Display omitted] •Inelastic scattering and plasmon excitations in W/Si – based multilayer mirrors.•Size-dependent intensity relationship and energy shift of plasmon excitation in multilayers.•Plasmon fine structure in film/vacuum and film/film interfaces.•Reflectivity of the mirrors. Thickness-dependent shift of energy position and fine structure of the collective oscillation of electron gas (plasmons) in the upper layer of silicon (Si) and tungsten (W) in the W/Si and Si/W multilayer mirrors was studied by X-ray photoelectron spectroscopy, respectively. In the spectra, doublet energy components of plasmon excitation were observed, which belong from the Si/vacuum or W/vacuum, and W/Si or Si/W interfaces. The plasmon excitation energy depended on the thickness of the Si and W layers in the multilayers. The intensity of the plasmon component along with the Si/vacuum or W/vacuum interfaces was increased with increasing the thicknesses of Si (or W). However, the intensity was declined along with the W/Si (or Si/W) interfaces. The fine structure of the plasmon was explained by proposing the framework of the electron scattering model in a thin film with the consideration of a semi-infinite solid. The contribution of surface and volume plasmons excitation to the reflectivity of the multilayer mirrors was described. The reflectivity of mirrors was higher for the lower value of plasmons excitation intensity.