A multiple ion cluster source is a fabrication technique based on the ion-spattering of a target material, which is placed into a vacuum chamber. The sputtered atoms aggregate forming nanoparticles in the gas phase that can be collected on arbitrary surfaces (soft landing) for different uses. In the case of a multiple ion-cluster source, up to three different elements can be combined to form nanoparticles with different structure.
Our infrastructure includes a scaled up multiple ion cluster source to have larger production rates and an ultra-high vacuum (UHV) environment to ensure high purity (no-capping), controlled size (can be tuned from 5 nm to 20 nm) and stoichiometry (e.g., different oxides can be made). This machine combines three different targets and allows to include gases in the reaction zone, in such a way that nanoparticles comprising up to three elements can be designed with complex architectures (core-shell, core-shell-shell, alloys, oxides…) and collected, with high throughput, on arbitrary surfaces. Substrates where nanoparticles are collected can be up to 80 mm x 20 mm. For smaller samples (typically 10 mm x 10 mm) it is possible to investigate the nanoparticles’ properties in-situ, e.g, catalytic activity. To this aim, the substrate can be annealed in UHV up 700ºC and the nanoparticles can be in-situ characterized by XPS, UPS, Auger, thermal desorption and Infrared spectroscopy. Moreover, formed nanoparticles can be annealed in-flight (i.e. in the gas phase, before landing) to achieve metastable atomic structures. These nanoparticles can be of interest for a large number of researchers requiring new materials for energy, health, optical or magnetic applications. In principle, all materials that can be sputtered (either DC or RF) can be used as source of nanoparticle elements. [Martinez et al. Sci. Rep. 8, 7250 (2018)]