Lenticular Ga-oxide nanostructures in thin amorphous germanosilicate layers - Size control and dimensional constraints. (June 2021)

• Record Type: Journal Article
• Authors: Remondina, Jacopo; Trabattoni, Silvia; Sassella, Adele; Golubev, Nikita V.; Ignat'eva, Elena S.; Sigaev, Vladimir N.; Acciarri, Maurizio; Schrode, Benedikt; Resel, Roland; Paleari, Alberto; Lorenzi, Roberto
• Is Part Of: Materials & design. Volume 204(2021)
• Publication Date: 2021-06
• Subjects: Nanostructured glassceramic materials -- Oxide thin films -- Gallium oxide -- Silicates -- X-ray scattering analysis -- Atomic-force-microscopy; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2021.109667
• Languages: English
• ISSNs: 0264-1275

Abstract

Abstract: Gallium incorporation in silicate glasses gives rise to compounds in which the nucleation and growth of Ga-oxide nanostructures can be designer controlled so as to obtain a number of functional properties for photonic applications. However, despite planar geometry pertains to a large part of modern technology, no information is available yet on the scalability of Ga-oxide segregation mechanisms in oxide thin films. In fact, incorporated Ga-oxide nanostructures have only been obtained in bulk materials. Here we show that deposition of Ga-alkali-germanosilicate thin films by radiofrequency-plasma sputtering gives rise to Ga-oxide nanostructures incorporated in an amorphous matrix. X-ray diffraction, X-ray reflectivity, small-angle X-ray scattering, and atomic force microscopy data unveil the formation of lenticular nanoaggregates, only a few nm thick, even in as-deposited materials as a result of two-dimensional aggregation of spinel-like Ga2 O3 nanoparticles. Importantly, the aggregate size distribution is controlled not only by the temperature but also by the film thickness when it is reduced from 10 2 nm to only a few nm. The results open the way to the design of oxide-in-oxide thin films with incorporated networks of nanostructures which can act as percolation paths for unconventional electric responses in neuromorphic functional systems. Graphical abstract: Unlabelled Image Highlights: Ga-oxide nanophases in films are directly obtained from glass target by sputtering. Ga-oxide in silicate films unveils a hierarchical architecture of nanoaggregation. Nano-segregation of Ga-oxide in silicate films occurs even in films few nm thick. Ga-oxide nanosize in oxide films can be controlled by treatments and thickness. Sputtering and treatments enable the use of Ga-oxide nanophases in planar geometry.