Персона: Бортко, Диана Владимировна
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Formation and properties of thin Mo and Mo oxide nanoparticle films
© 2019 Elsevier B.V.The paper presents a study of thin Mo films, consisted of individual nanoparticles of 3.5–5.5 nm in diameter. Their chemical, electron, and optical properties are studied. It is shown that thin films consisting of individual Mo nanoparticles can be formed from the gas phase by magnetron sputtering. Atmospheric exposure leads to the formation of MoOx oxide shell around the metal nuclei of Mo nanoparticles in the films and changes in its electronic structure. Optical properties of the obtained films consisted of ‘core–shell’ Mo@MoOx nanoparticles are investigated. It is shown that the absorption window falls on the range of 190–300 nm, which can be used in the development of single-photon detectors sensitive to weak ultraviolet signals from long-live states, for example from Th-229 low-lying isomeric state.
Thin Ta/Ta oxide core-shell nanoparticle film size-dependent energy structure
© 2020 Elsevier B.V.The paper presents the research of thin films, consisting of spherical monodisperse Ta particles. For different samples particle sizes varied from 1.3 nm to 5.8 nm. The films were also exposed to the atmosphere for oxidation, which resulted in formation of a core-shell particle structure, where core was metal and shell was Ta oxide (Ta2O5). Dependency of bandgap Egap and valence band offset (VBO) on particle size has been investigated for the structure by using the X-ray photoelectron spectroscopy (XPS) and reflected electron energy loss spectroscopy (REELS) methods. We have found, that Egap decreases from 4.72 eV to 4.47 eV whereas VBO decreases from 3.50 eV to 2.95 eV with increasing the particle size. A new method of a fine regulation of the electronic structure is suggested, particularly for the application in ultraviolet (UV) photodetector design for low-lying nuclear and electron transitions detection.