Emanuele Barborini
Tethis SpA , Italy
Title: Transition metal–spinel nanoporous multi--layers by double beam cluster beam deposition
Biography
Biography: Emanuele Barborini
Abstract
The integration of nanostructured layers into devices is the pivotal step to exploit peculiar properties of nanoscale systems. This particularly holds for atomic clusters and nanoparticles, whose manipulation is known to be a cumbersome process. For instance, wet-chemistry approach may leave contaminations affecting the final application, while high-temperature calcination step of sol-gel approach severely limits the choice of the platform hosting the nanomaterial. Cluster Beam Deposition (CBD) has been recognized as a method overcoming many of those drawbacks and carrying beneficial features such as room temperature deposition, huge porosity due to nanoparticles soft-assembling, hard-mask patterning. We report on a study where a double-beam deposition system has been developed to combine on the same substrate nanoparticles produced by Flame Spray Pyrolysis (FSP), through FlameBeam source, and atomic clusters produced by electrical discharges, through Pulsed Microplasma Cluster Source (PMCS). FlameBeam source exploits the combination of a FSP burner, operating at atmospheric pressure, with a "quenching nozzle" that captures the nanoparticles generated by FSP and concentrates them into a gas stream directed into a vacuum deposition chamber. PMCS exploits a pulsed plasma jet impinging on a metal target to vaporize atoms in Argon atmosphere. Atoms then re-aggregate in clusters that are carried by nozzle expansion towards the same vacuum deposition chamber to which FlameBeam is faced. FlameBeam materials library includes simple oxides, complex oxides, noble metals and their combinations. PMCS materials library includes transition metals, noble metals, alloys. As paradigmatic example of the capabilities of the double-beam deposition system described here, results on nanoporous Cu-MgAl2O4 multi-layer synthesis and characterization will be shown, where Cu clusters layer by PMCS is deposited on MgAl2O4 nanoparticles layer by FlameBeam. Remarkably, MgAl2O4 layer shows the spinel structure. This suggests possible interesting roles in catalysis field for the nanoporous metal-spinel systems by FlameBeam-PMCS combination.