Effects of Oxygen Adsorption on Morphological Evolution of Epitaxial Ag Island Films Grown on Si

Fabrication of Platinum Nanoparticles with Different Morphologies by Thermal Dewetting in the Presence of Residual Oxygen and Their Optical Properties

“…The preferential oxygen adsorption on high-index facets and the resultant reduction of surface energy lead to a reduction in surface energy anisotropy, which makes the formation of high-index facets possible. This reduction in surface energy anisotropy due to oxygen adsorption was also observed in the thermal dewetting of Ag and Ni films, respectively, with the formation of faceted Ag islands on Si 35 and faceted Ni particles on sapphire 38 substrates.…”

“…32 Differences in thermal dewetting atmosphere have been shown to influence the dewetting behavior and the morphology evolution of metal thin films. 33,36,37 Particularly, in their study on the effect of oxygen adsorption on the morphological evolution of Ag films on Si substrates, Ye et al 35 have shown that oxygen enhances the dewetting rate of Ag thin films which they attribute to the decrease in the activation barrier for the surface diffusion of Ag atoms due to oxygen adsorption. With the reduced activation energy, surface diffusion could take place more easily, leading to a faster dewetting process, as thermal dewetting is a solid-state dewetting process driven by surface diffusion.…”

“…In addition to the thermal dewetting temperature and metal film thickness, another important parameter that will affect the dewetting morphology of metal films is the ambient conditions under which thermal dewetting occurs. Investigations of thermal dewetting of Ag films in oxygen-poor (e.g., vacuum) and oxygen-rich atmospheres have shown that oxygen enhances the rate of dewetting and significantly affects the morphology of dewetted Ag, − which is attributed to the increase in surface diffusivity and the lowering in surface energy of Ag due to the presence of oxygen. Geissler et al reported the effect of H 2 pressure on the size of Ni NPs formed during thermal dewetting of Ni films on SiO 2 (25 nm)/Si substrates, where the NP size was seen to increase along with a decrease in the NP number density when the H 2 pressure increased.…”