First ZnGa2O4 transparent ceramics. Issue 9 (August 2021)

• Record Type: Journal Article
• Authors: Mével, Claire; Carreaud, Julie; Delaizir, Gaëlle; Duclère, Jean-René; Brisset, François; Bourret, Julie; Carles, Pierre; Genevois, Cécile; Allix, Mathieu; Chenu, Sébastien
• Is Part Of: Journal of the European Ceramic Society. Volume 41:Issue 9(2021)
• Page Start: 4934
• Page End: 4941
• Publication Date: 2021-08
• Subjects: ZnGa2O4 transparent spinel ceramic -- STEM-HAADF -- Microstructure -- SPS sintering -- Red persistent luminescence; Ceramic materials -- Periodicals; Composite materials -- Periodicals; Matériaux céramiques -- Périodiques; Composites -- Périodiques; Ceramic materials; Composite materials; Periodicals; Electronic journals; 666.05
• DOI: 10.1016/j.jeurceramsoc.2021.03.038
• Languages: English
• ISSNs: 0955-2219

Abstract

Abstract: Transparent polycrystalline ZnGa2 O4 ceramics are synthesized, for the first time, by combining high-energy ball milling, solid-state reaction and spark plasma sintering. They appear transparent in both the visible and near infrared (up to 9 μm) ranges after a post-SPS annealing in air converting the raw semiconductor into an electrical insulator. The maximum of transmittance is reached in the near infrared region, at around 2.5 μm, with a value of 78 % (1 mm thick sample) close to the maximum value of transmittance previously measured for single crystals. These transparent ceramics present a classic cubic spinel ZnGa2 O4 structure and a dense microstructure (> 99 %) attained without sintering aids, with an average grain size of 600 nm and a random orientation of the crystallites. TEM observations performed on thin foils have revealed limited nanometer scale intergranular porosity which does not affect much the transparency. As a proof of interest, red long-lasting luminescence arising from the entire sample volume is observed in these Cr 3+ doped transparent ceramics. This innovative work is anticipated to further drive the development of transparent ZnGa2 O4 ceramics towards a wider range of performing optical applications such as laser emission.