Clustering of gold atoms in ion-implanted silica after thermal annealing in different atmospheres

Abstract

The clustering process of gold atoms in ion-implanted silica, during annealing in different atmospheres, is experimentally investigated and phenomenologically described. With respect to inert (Ar) or reducing (H2-Ar) atmosphere, annealing in oxidizing (air) atmosphere is the most effective in promoting cluster formation above 700–800°C due to a thermally activated correlated diffusion of gold atoms and excess oxygen molecules coming from the atmosphere

Silver and gold doping of SiO2 glass by solid-state field-assisted diffusion

“…Actually, the ionic mobility inside a solid matrix can be strongly limited or enhanced by changing the environment (vacuum, argon, nitrogen, oxygen, hydrogen, forming gas; wet or dry atmosphere; etc.) in which the process is realized [24,25]. This happens because the possibility to have many ionized atoms available for electric field-assisted diffusion depends on the presence of deep level acceptors in SiO 2 available to capture electrons [24].…”

Ion irradiation for controlling composition and structure of metal alloy nanoclusters in SiO2

“…On the other hand, the satellite clusters averaged diameter initially increases as a function of radiation dose and then reaches a constant of D $ 1.8 nm. This can be understood by assuming that the cluster growth follows an Ostwald ripening process and that prevails over a possible cluster density increase due to a heterogeneous nucleation on structural defects on SiO 2 [22,23].…”

Growth of Cookie-like Au/NiO Nanoparticles in SiO2 Sol–Gel Films and Their Optical Gas Sensing Properties

“…11,12 Indeed, it has been already demonstrated 12 that Au atoms diffuse readily in SiO 2 at temperatures equal to, or higher than, 600°C in an oxygen containing atmosphere. The Au nanocluster growth is coupled with the parallel nucleation of the NiO crystalline phase, which probably tends to use the Au (111) planes as a structural template for nucleating the growth, therefore forming the double structured cookie-like Au/NiO clusters found in the 600°C and more distinctly in the 700°C annealed sample.…”