title: IR laser photodeposition of a-Fe/Si films developing nanograins of ferrisilicate, iron disilicide and rare hexagonal iron upon annealing.
abstract: 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.
authors.affiliation: Laboratory of Laser Chemistry, Institute of Chemical Process Fundamentals, ASCR, 16502, Prague, Czech Republic.
authors.forename: J
authors.initials: J
authors.lastname: Pola
authors.forename: M
authors.initials: M
authors.lastname: Urbanová
authors.forename: D
authors.initials: D
authors.lastname: Pokorná
authors.forename: S
authors.initials: S
authors.lastname: Bakardjieva
authors.forename: J
authors.initials: J
authors.lastname: Šubrt
authors.forename: Z
authors.initials: Z
authors.lastname: Bastl
authors.forename: M A
authors.initials: MA
authors.lastname: Gondal
authors.forename: H M
authors.initials: HM
authors.lastname: Masoudi
mesh_terms: D003460:Crystallization; D007501:Iron / Q000737:chemistry*; D058085:Iron Compounds / Q000737:chemistry*; D007834:Lasers; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure; D036103:Nanotechnology / Q000379:methods; D010782:Photolysis; D017640:Silicates / Q000737:chemistry*; D012825:Silicon / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman
chemical_list: D058085:Iron Compounds; D017640:Silicates; D007501:Iron; D012825:Silicon