Dependence of inherent selective atomic layer deposition of FeOx on Pt nanoparticles on the coreactant and temperature

Selective growth of metal oxides on metal via atomic layer deposition (ALD) has attracted great interest due to their potential applications in the semiconductor industry, as well as energy and environment fields. In this work, the influence of an oxidizing coreactant and the reaction temperature on the selective growth of FeOx on the facets of Pt nanoparticles and low coordination edge sites are studied via in situ Fourier transform infrared spectroscopy (FTIR) and first-principles calculations combined with microkinetic methods. It is found that selective deposition on the low coordination edge sites of Pt nanoparticles is realized when using O3 as the coreactant at low temperature (150 °C), while the ALD reaction takes place only above 250 °C without selectivity when using O2 as the coreactant. Based on density functional theory calculations, the edge-selective growth of FeOx on Pt is attributed to energy barrier differences for ALD reactions taking place at the Pt(111), Pt(100), and edge sites. Moreover, reaction rate analysis indicates that the selectivity of FeOx ALD on Pt nanoparticles is temperature dependent and that a high temperature suppresses the selectivity between different sites, which is also confirmed by the FTIR results.