Title: Structural and chemical changes during the growth of Fe nanoparticles in SiO₂ under low energy ion implantation

Authors: Jérôme Leveneur; John Kennedy; G.V.M. Williams; Masato Sasase; James B. Metson; Andreas Markwitz

Addresses: National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt, New Zealand; Department of Chemistry, The University of Auckland, Private Bag 92019, Auckland, New Zealand ' National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt, New Zealand; The MacDiarmid Institute for Advanced Materials and Nanotechnology, SPCS, Victoria University, P.O. Box 600, Wellington, New Zealand ' The MacDiarmid Institute for Advanced Materials and Nanotechnology, SPCS, Victoria University, P.O. Box 600, Wellington, New Zealand ' The Wakasa-wan Energy Research Center, 64-52-1, Nagatani, Tsuruga Fukui, 914-0192, Japan ' Department of Chemistry, The University of Auckland, Private Bag 92019, Auckland, New Zealand; The MacDiarmid Institute for Advanced Materials and Nanotechnology, SPCS, Victoria University, P.O. Box 600, Wellington, New Zealand ' National Isotope Centre, GNS Science, 30 Gracefield Road, Lower Hutt, New Zealand; The MacDiarmid Institute for Advanced Materials and Nanotechnology, SPCS, Victoria University, P.O. Box 600, Wellington, New Zealand

Abstract: Low energy (15 keV) Fe implantation into SiO₂ (400 nm) on Si initially leads to the formation of very small Fe nanoparticles. The Fe nanoparticles grow in size and remain crystalline as the fluence is increased. At the same time there is Si and oxygen sputtering that reduces the thickness of the SiO₂ layer. It is this sputtering that leads to Fe nanoparticles that protrude from the surface for high Fe fluences of at least 5 × 10¹⁶ at.cm⁻². The surface nanoparticles develop an oxide layer when exposed to air. Fe silicides (probably FeSi₂) also occur for these high fluences. Their formation is likely to occur because sputtering leads to a Si excess near the surface.

Keywords: iron nanoparticles; ion implantation; XANES; XPS; RBS; nanotechnology; structural changes; chemical changes; Fe nanoparticles; SiO2; silicon dioxide; silica; sputtering.

DOI: 10.1504/IJNT.2014.060567

International Journal of Nanotechnology, 2014 Vol.11 No.5/6/7/8, pp.466 - 476

Published online: 15 Dec 2014 *

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