Effects of He Ambient on Formation of Si Particles Using Pulsed Ion-Beam Evaporation

Abstract

A pulsed ion-beam evaporation (IBE) technique is used to ablate Si species from bulk Si target onto quartz substrates. Large round-shaped droplets up to a few µm are predominantly formed in vacuum, whereas introduction of He gas could result in formation of particles with decreased size up to a few hundreds nm. A slight oxidation of Si particles is found even in vacuum condition, revealed by surface composition analysis using X-ray photoelectron spectroscopy (XPS). Note that the presence of He ambient obviously promotes the oxidation of as-deposited Si species. The changes in morphology and composition of formed Si particles are attributable to an enhanced interaction between ablated Si plume and the ambient gas with an increased pressure.