Substrate dependent buffer‐layer assisted growth of nanoclusters

Abstract

The role of the substrate on the morphology of nanometer size clusters fabricated by buffer layer assisted growth (BLAG) was studied using scanning tunneling microscopy. Clusters of Fe and Co were deposited on Ag(111), Cu(100), Rh(111), and Pt(111) surfaces using identical BLAG parameters, which are temperature, as well as metal and buffer layer coverage. Semi‐hemispherical clusters are found on Ag(111) and Cu(100), while flat monolayer high islands are observed on Rh(111) and Pt(111) due to complete wetting. The results of this study are in agreement with the common notion that BLAG is useful to deposit clusters of virtually any material on any substrate, however, the shape, size, and lateral distribution of the resulting clusters depend strongly on the substrate surface free energy and diffusion processes.

Magnetic surface nanostructures

“…Recently, the intrinsic magnetic moment formation was studied on Rh clusters that were in direct contact with Ag(100) and Pt(997) substrates [283] and decoupled from the metal substrate by a thin Xe buffer layer [285]. A sketch of the experimental parameters is given in the inset of figure 19.…”

“…(iii) Also alloying of the Rh with the substrate atoms cannot be excluded. Ab initio calculations actually predict the quenching of orbital and spin moments in alloyed nanostructures [285]. Future experiments must therefore exploit advanced synthesis methods with greater structural control, such as atomic manipulation, to study emergent magnetism in Rh or other nanostructures.…”

“…(i) The Rh clusters on the Xe buffer layer grow in size when the Xe is desorbed. The clusters that are in contact with the metal substrates are thus larger than the clusters on the Xe, and likely larger than the critical size of ≈100 atoms [285]. (ii) The published calculations in [278,284] study specific atomic arrangements and cluster sizes, such as pseudomorphic linear chains and related structures.…”

A Low-Energy Ion Scattering Approach for Studying Au Nanoclusters Grown on an H2O Buffer Layer

“…Buffer layer assisted growth (BLAG), initially developed by Weaver and co-workers, is a novel method for growing nanoclusters onto nearly any substrate. , BLAG has been used to produce gold (Au), silver (Ag), and germanium (Ge) clusters, Au and palladium (Pd) bimetallic clusters, and II–VI quantum dots on various substrates. − Although direct deposition of metal atoms spontaneously forms nanoclusters on many oxides and other stable surfaces through a Volmer–Weber growth mode, only certain combinations of metals and substrates can be used. The materials that do not work either have a high surface free energy that favors the formation of a dispersed film or they chemically react with the substrate material.…”

Cobalt nanoclusters on metal-supported Xe monolayers: Influence of the substrate on cluster formation kinetics and magnetism

“…We have already demonstrated that indeed, under these conditions, the morphology of the substrate underneath can be used as a template to tailor the cluster size and their lateral arrangement on the substrate. 7,8 In the present paper we investigate the mechanisms driving the dynamics during BLAG in detail, focusing on the early stage of cluster formation. The combined use of variable temperature scanning tunneling microscopy ͑VT-STM͒ and x-ray magnetic circular dichroism ͑XMCD͒ measurements allows us to monitor directly the growth mechanism of Co/Xe in case of absorption on two electronically very different metal substrates: Ag͑111͒ and Pt͑111͒.…”