Formation, Structure and Optical Properties of Nanocrystalline BaSi₂ Films on Si(111) Substrate

Abstract:

BaSi₂ thin films were formed on Si (111) substrate by solid-phase epitaxy (SPE) (UHV deposition) using the template technology followed by vacuum annealing at temperatures of 600 °C and 750 °C. After the deposition and annealing barium silicide films were characterized by Auger electron spectroscopy, grazing incidence x-ray diffraction (GIXRD) and atomic-force microscopy (AFM). It was established that the films annealed at T = 600 °C are polycrystalline with the structure of the orthorhombic BaSi₂, with grain sizes of 100-200 nm. Higher anneal temperature (T=750 °C) leads to increase of diffraction peak intensity of BaSi₂ phase with grain coagulation into 300-400 nm islands. It was confirmed that nanocrystalline BaSi₂ films are characterized by a direct fundamental interband transition at 1.3 eV, the second interband transition with an energy of 2.0 eV, own phonon structure with wave number peaks at 112, 119, 146 and 208 cm^-1 and a high density of defect states within the band gap, which provide a noticeable subband absorption at energies of 0.8 – 1.1 eV.

• Periodical: Solid State Phenomena (Volume 245)
• Pages: 42-48
• DOI: https://doi.org/10.4028/www.scientific.net/SSP.245.42
• Online since: October 2015
• Authors: Dmitrii Vladimirovich Fomin*, Victor Leonidovich Dubov, Konstantin Nickolaevich Galkin, Dmitrii L. Goroshko, Andrei Mikhailovich Maslov, Nikolay G. Galkin, Rafael Il'yasovich Batalov, Vladimir Alekseevich Shustov
• Keywords: Barium Disilicide, Fundamental Absorption, Nanocrystallites, Optical Functions, Silicon, Solid-Phase Epitaxy, Stress, Structure, Template, Thin Film

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