X-ray photoelectron spectroscopic study of the formation of catalytic gold nanoparticles on ultraviolet-ozone oxidized GaAs(100) substrates

A comprehensive study of the oxide formed on GaAs by exposure to ultraviolet light and ozone (UV-ozone), and the evolution of Au nanoparticles on UV-ozone treated GaAs(100) substrates, has been carried out using x-ray photoelectron spectroscopy. The UV-ozone oxide has been found to consist of oxides of gallium and arsenic in addition to having a significant contribution from elemental arsenic concentrated mostly at the substrate-oxide interface. An intermediate suboxide species −AsxGa2O is found to make up a substantial part of the oxide layer, mostly near the surface region, whereas the interface to bulk GaAs is dominated by Ga2O3. As2O3 is found to be the dominant oxide in the initial UV-ozone oxide layer, while the oxide layer becomes rich in Ga2O3 as the sample is annealed at 500 °C for 300 s in a dry nitrogen environment. It is also found that gold does not alloy with Ga during the formation of gold nanoparticles by dewetting from the UV-ozone oxidized GaAs substrate.

X-ray photoelectron spectroscopic study of the formation of catalytic gold nanoparticles on ultraviolet-ozone oxidized GaAs(100) substrates Journal Articles