An in situ microbalance
and infrared spectroscopic
study of alternating exposures to Me2Au(S2CNEt2) and ozone illuminates the organometallic chemistry that
allows for the thermal atomic layer deposition (ALD) of gold. In situ quartz crystal microbalance (QCM) studies resolve
the nucleation delay and island growth of Au on a freshly prepared
aluminum oxide surface with single cycle resolution, revealing inhibition
for 40 cycles prior to slow nucleation and film coalescence that extends
over 300 cycles. In situ infrared spectroscopy informed
by first-principles computation provides insight into the surface
chemistry of the self-limiting half-reactions, which are consistent
with an oxidized Au surface mechanism. X-ray diffraction of ALD-grown
gold on silicon, silica, sapphire, and mica reveals consistent out-of-plane
oriented crystalline film growth as well as epitaxially directed in-plane
orientation on closely lattice-matched mica at a relatively low growth
temperature of 180 °C. A more complete understanding of ALD gold
nucleation, surface chemistry, and epitaxy will inform the next generation
of low-temperature, nanoscale, textured depositions that are applicable
to high surface area supports.