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

作者：Salvo C R; Yarmoff J A^*

来源：Langmuir, 2017, 33(22): 5439-5445.

DOI：10.1021/acs.langmuir.7b00386

A novel form of alkali low-energy ion scattering is used to probe the deposition of
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nanoclusters onto a solid surface via buffer layer assisted growth (BLAG) in ultrahigh vacuum. A thin amorphous solid water (ASW) buffer layer grown on a TiO2(110) single crystal cooled to 100 K. Au atoms deposited onto this layer arrange themselves into nanoclusters. The sample is then annealed to 320 K to desorb the ASW and enable the clusters to soft-land onto the substrate. Time-of-flight low-energy ion scattering, using Li+, Na+, and K+ projectiles, probes the materials during each step of the BLAG process to measure the surface composition and reveal the details of how the clusters form. The neutralization probability of Na+ singly scattered from the Au nanoclusters indicates that they increase in size after annealing and that the magnitude of the increase is a function of the buffer layer thickness. The adsorption of a thin, incomplete water layer prior to Au deposition forms nanoclusters that are possibly even smaller than those produced by direct deposition onto) the clean substrate.

• 出版日期2017-6-6