IR laser photodeposition of a-Fe/Si films developing nanograins of ferrisilicate, iron disilicide and rare hexagonal iron upon annealing

• Published in: Dalton transactions : an international journal of inorganic chemistry Vol. 41; no. 6; pp. 1727 - 1733
• Main Authors: Pola, J, Urbanov, M, Pokorn, D, Bakardjieva, S, ubrt, J, Bastl, Z, Gondal, M. A, Masoudi, H. M
• Format: Journal Article
• Language: English
• Published: England 14.02.2012
• Subjects: Crystallization; Disilicides; Intermetallic compounds; Intermetallics; Iron; Iron - chemistry; Iron compounds; Iron Compounds - chemistry; Lasers; Nanomaterials; Nanostructure; Nanostructures - chemistry; Nanostructures - ultrastructure; Nanotechnology - methods; Photolysis; Semiconductors; Silicates - chemistry; Silicides; Silicon - chemistry; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c1dt11587a

IR laser-induced gas-phase photolysis of Fe(CO) 5 SiH 4 mixtures occurs as SiH 4 -photosensitized decomposition of Fe(CO) 5 is accelerated by products of this decomposition and it results in deposition of amorphous Si/Fe nanocomposite films. Analyses of the deposited and subsequently annealed solid films were made by FTIR, Raman and X-ray photoelectron spectroscopy, X-ray diffraction and electron microscopy. The deposited films are amorphous, contain crystalline nanostructures of iron silicide FeSi 2 and undergo atmospheric oxidation in topmost layers to iron oxide and hydrogenated silicon oxide. Upon annealing they develop nanocrystalline structures of ferrisilicate, Fe 1.6 SiO 4 , carbon-encaged iron disilicide, FeSi 2 , and very rare hexagonal (high-pressure) Fe surviving at ambient conditions. The mechanism of formation of these nanostructures is discussed in terms of gas-phase and solid-phase reactions. Infrared laser co-photolysis of silane and iron pentacarbonyl takes place via a complex cleavage of both precursors and affords deposition of amorphous nanostructured Fe/Si composite films incorporating nanocrystalline FeSi 2 , Fe 1.6 SiO 4 and Fe.