title: Directed assembly of Au and Fe nanoparticles on a TiOx/Pt(111) ultrathin template: the role of oxygen affinity.
abstract: The essential role of O affinity in the directed assembly of size-selected Au and Fe nanoparticles (NPs) on a TiO(x)/Pt(111) ultrathin oxide phase, an effective template for size selected metal NP growth, is revealed through scanning tunneling microscopy and density-functional calculations. A weakly interacting element (Au) diffuses rapidly and gets trapped in the vacancy defects (picoholes) located inside parallel rows (troughs, spaced 1.44 nm apart) peculiar to the film structure, producing size-selected NPs arranged in regular linear arrays aligned along the troughs. In contrast, an element with greater O affinity (Fe) experiences higher diffusion barriers, and the growth is dominated by kinetic effects, with a less effective preferential nucleation and the appearance of irregular NP morphologies.
authors.affiliation: Dipartimento di Matematica e Fisica, Università Cattolica del Sacro Cuore, via dei Musei 41, I-25121 Brescia, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: Cavaliere
authors.forename: Iskandar
authors.initials: I
authors.lastname: Kholmanov
authors.forename: Luca
authors.initials: L
authors.lastname: Gavioli
authors.forename: Francesco
authors.initials: F
authors.lastname: Sedona
authors.forename: Stefano
authors.initials: S
authors.lastname: Agnoli
authors.forename: Gaetano
authors.initials: G
authors.lastname: Granozzi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Barcaro
authors.forename: Alessandro
authors.initials: A
authors.lastname: Fortunelli