In situ characterization of nucleation, growth and sintering behaviour of metal nanoparticles synthesized by atomic layer deposition using scanning probe and x-ray characterization techniques

This experimental project aims to study, understand and control the mechanisms that govern, first, the nucleation and growth of noble metal nanoparticles by atomic layer deposition (ALD) and, second, the thermal sintering behaviour of the nanoparticles on different oxide substrates. In view of catalytic applications, we will focus on ALD chemistries for Pt, Pd and Ru. Our experimental approach utilizes x-ray based surface-sensitive characterization and atomic resolution imaging techniques that can be applied in situ or without vacuum break (in vacuo). Within the scope of this proposal, a dedicated vacuum chamber for ALD and annealing experiments will be built and coupled to a new vacuum cluster facility comprising a ThetaProbe x-ray photoelectron spectroscope (XPS) and a variable temperature scanning probe microscope (SPM) installed at the UGent Department of Solid State Sciences. In addition, in situ grazing incidence small angle x-ray scattering (GISAXS) studies will be performed at synchrotron facilities. This combination of complementary techniques is unique world-wide and will be utilized to obtain a fundamental understanding of the chemical surface reactions driving noble metal ALD growth and of the key effects that control the morphological evolution during nucleation, growth and sintering of the metal nanoparticles.