title: Encapsulation of Au Nanoparticles on a Silicon Wafer During Thermal Oxidation.
abstract: We report the behavior of Au nanoparticles anchored onto a Si(111) substrate and the evolution of the combined structure with annealing and oxidation. Au nanoparticles, formed by annealing a Au film, appear to "float" upon a growing layer of SiO2during oxidation at high temperature, yet they also tend to become partially encapsulated by the growing silica layers. It is proposed that this occurs largely because of the differential growth rates of the silica layer on the silicon substrate between the particles and below the particles due to limited access of oxygen to the latter. This in turn is due to a combination of blockage of oxygen adsorption by the Au and limited oxygen diffusion under the gold. We think that such behavior is likely to be seen for other metal-semiconductor systems.
authors.affiliation: Wolfson Nanoscience Laboratory, School of Chemistry, Cardiff University , Cardiff CF10 3AT, United Kingdom ; Rutherford Appleton Laboratory, Research Complex at Harwell (RCaH) , Harwell, Oxon OX11 0F, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Bowker
authors.forename: J J
authors.initials: JJ
authors.lastname: Crouch
authors.forename: A F
authors.initials: AF
authors.lastname: Carley
authors.forename: P R
authors.initials: PR
authors.lastname: Davies
authors.forename: D J
authors.initials: DJ
authors.lastname: Morgan
authors.forename: G
authors.initials: G
authors.lastname: Lalev
authors.forename: S
authors.initials: S
authors.lastname: Dimov
authors.forename: D-T
authors.initials: DT
authors.lastname: Pham