The Metastable, Glasslike Solid‐State Phase of HAlO and Its Transformation to Al/Al₂O₃ Using a CO₂ Laser.

Abstract

Using a CO 2 Laser. -Glass-like films of the title compound are synthesized by gas-phase decomposition of (tBuOAlH 2 ) 2 on metallic substrates heated to 240-250°C at 0.01-0.1 atm. The samples are characterized by powder XRD, IR, NMR MAS, and XPS spectroscopy. The HAlO layer, when heated to 450°C or when exposed to a CO 2 laser, transforms to an almost stoichiometric Al/Al 2 O 3 composite. Microstructures that are characterized by different chemical compositions and different optical contrasts of the "drawing", relative to the surrounding matrix, may be generated with an X/Y-table and a CO 2 laser. -(VEITH*, M.; ANDRES, K.; FABER, S.; BLIN, J.; ZIMMER, M.; WOLF, Y.; SCHNOECKEL, H.; KOEPPE, R.; DE MASI, R.; HUEFNER, S.; Eur.

Role of UV Plasmonics in the Photocatalytic Performance of TiO2 Decorated with Aluminum Nanoparticles

“…Following sputter deposition of a TiO 2 thin film, a gas aggregation source (GAS, as shown schematically in Figure a) , was used to decorate the deposited film with Al NPs. In addition to argon (Ar), we introduced an extremely low amount of oxygen (O 2 ) during sputtering to promote Al cluster nucleation by binding O 2 to sputtered Al atoms. − It is known that Al–O binding is quite stable in comparison to the low dimer binding energy of Al–Al . While at 0.001–0.400 SCCM O 2 flow range we were able to produce Al clusters (confirmed by both, in situ quartz crystal microbalance monitoring (Figure S1) and scanning electron microscopy (SEM) analysis (Figures b and S2 and S3)), at higher O 2 flow rates (>0.400 SCCM), we did not observe any cluster formation (Figure b), which might be attributed to target poisoning (oxidation).…”

“…This oxide shell protects Al NPs from further oxidation and agglomeration. An X-ray photoelectron spectroscopy (XPS) spectrum (Figure d) verified the coexistence of an ultrathin oxide shell and the metallic Al core (more details are given in the Supporting Information, section 2) …”