Tuning size and coverage of Pd nanoparticles using atomic layer deposition

• Published in: Applied surface science 2021-02, Vol.539, p.148238, Article 148238
• Main Authors: Feng, Ji-Yu, Ramachandran, Ranjith K., Solano, Eduardo, Minjauw, Matthias M., Van Daele, Michiel, Vantomme, André, Hermida-Merino, Daniel, Coati, Alessandro, Poelman, Hilde, Detavernier, Christophe, Dendooven, Jolien
• Format: Article
• Language: English
• Subjects: Atomic layer deposition; Palladium; Particle morphology; Supported metal nanoparticles; Well-designed catalysts
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.148238

[Display omitted] •Synchrotron-based in situ GISAXS and XRF are applied during Pd plasma-enhanced ALD.•The nucleation and the evolution in Pd nanoparticle morphology is investigated.•Pre-pulses with trimethylaluminum enhance the initial coverage of Pd nanoparticles.•The role of extra O2 plasma pulse, with H2 plasma as co-reactant, is investigated.•Precise control of the Pd nanoparticle dimensions and coverage is achieved. The morphology evolution of supported palladium nanoparticles (Pd NPs) during plasma-enhanced atomic layer deposition using palladium hexafluoroacetylacetonate (Pd(hfac)2) as precursor was investigated using in situ and ex situ X-ray fluorescence (XRF) and grazing incidence small angle X-ray scattering (GISAXS), as well as ex situ scanning electron microscopy (SEM). The initial areal density of Pd NPs increases through adding cycles of the three-step process using Pd(hfac)2, H2 plasma and trimethylaluminum (TMA) prior to the standard Pd(hfac)2 + H2 plasma process. The participation of an O2 plasma exposure as additional co-reactant before or after the H2 plasma step also plays a role in the nucleation density and particle coalescence, affecting also the shape of the deposited particles. Based on the gathered knowledge, a synthetic approach that enables precise control of the Pd nanoparticle dimensions and coverage is developed.