Precipitation phenomena in high-dose iron-implanted silica and annealing behavior

Abstract

The effects of high-dose iron implantation into high-purity fused silica have been investigated by conversion-electron Mössbauer spectroscopy, transmission electron microscopy, Rutherford backscattering, and optical spectroscopy. In addition to isolated Fe2+ ions, samples subjected to doses of 4⊠1016 and 6 ⊠ 1016 ions cm−2 were found to contain homogeneously dispersed, equidimensional, crystalline particles ⋍2 nm, similar to Fe3O4. Precipitated spherical particles of metallic α-Fe⋍4 nm were observed in samples receiving a dose of ⋍ 1017 ions cm−2; as the dose was raised to 2.5 ⊠ 1017 ions cm−2 the mean size of these particles reached ⋍ 30 nm. Annealing in air to 800°C resulted in the growth of acicular grains of α-Fe2O3 ⋍ 20–300 nm. The optical spectra of the implanted layers are compared with the predictions of small particle theory.

Optical properties of Ag nanocrystals in Sc and O sequentially implanted silica

“…If nanoparticles of either elemental Sc or various compounds with oxygen or silicon were formed, effective medium theory suggests increasing absorption with decreasing wavelength, as 1/k is expected [2,31,38,39]. Absorption due to the formation of non-elemental and elemental metal nanoparticles has been reported for a variety of implanted transition metal ions, Ti, V, Cu, Fe, Cr, Mn and Co as well as other ions like Ga, Bi and Pb [1,2,38]. From this we conclude that this small absorption suggests little or minimal interaction of the Sc and the silica network in the form of the formation of nanoparticles.…”

Microstructure and electrical properties of Sn nanocrystals in thin, thermally grown SiO2 layers formed via low energy ion implantation

“…This technique can control the depth distribution of a desired species and is extensively used in semiconductor technology. To the best of our knowledge, Au, 4 Cu, 5 Ag, 6,7 Fe, 8 and Sb 9 metal nanocrystals implanted in glasses have been reported on to date. However, most of these have been studied from the perspective of their large nonlinear optical properties.…”

Structure and magnetic properties of Fe–Pd silica composites prepared by sequential ion implantation

“…The main difference in the hysteresis loops, measured at 3 K, of the only-Fe sample and of Pd-Fe ones is the This may be related with the oxidation of some Fe atoms, as it was observed by Perez et al [11] in similar samples, which give a smaller magnetic contribution. The enhancement of the magnetic moment per atom in the Pd-Fe samples are in agreement with the literature data [12,13].…”