Optical glassceramics are an important class of functional materials mainly employed in photonic and optoelectronic applications, as well as for advanced fiber optics. Here we present recent results on phase separation processes and optical properties of alkali germanosilicate glasses containing gallium oxide nanoparticles. Samples, with typical composition 7.5Li2O–2.5Na2O–20Ga2O3–35GeO2–35SiO2 (mol%), are obtained from the melt-quenching method. The resulting glasses are completely amorphous, but show phase separation, on the nanometer scale, deriving from liquid–liquid phase separation in the melt. Nanocrystallization of gallium oxide, in its metastable gamma phase, is thermally activated inside the matrix at about 615 °C. Treatment at higher temperature causes the formation of LiGa5O8 polymorph by Li ion diffusion from the surrounding matrix to the nanocrystals. In a second step, a further increment of temperature induces an order-to-disorder LiGa5O8 change that finally dissociates causing the formation of beta-Ga2O3. Neutron scattering, X-ray diffraction analysis, differential scanning calorimetry, and transmission electron microscopy studies have been performed so as to assess nucleation and crystal growth mechanisms. Parallel to morphological studies, we also present optical response of these systems, characterized by a strong UV-excited blue luminescence due to intrinsic defects and its dependence on thermal treatments. - See more at: http://www.european-mrs.com/2015-fall-symposium-w-european-materials-research-society#sthash.pRj5G4Gf.dpuf

Lorenzi, R., Azarbod, A., De Trizio, L., Ignat'Eva, E., Sigaev, V., Golubev, N., et al. (2015). Phase separation and optical properties of nanostructured oxide-in-oxide Ga2O3-containing germanosilicate glasses. Intervento presentato a: E-MRS 2015 – European Materials Research Society Fall Meeting, Warsaw.

Phase separation and optical properties of nanostructured oxide-in-oxide Ga2O3-containing germanosilicate glasses

LORENZI, ROBERTO
Primo
;
PALEARI, ALBERTO MARIA FELICE
Ultimo
2015

Abstract

Optical glassceramics are an important class of functional materials mainly employed in photonic and optoelectronic applications, as well as for advanced fiber optics. Here we present recent results on phase separation processes and optical properties of alkali germanosilicate glasses containing gallium oxide nanoparticles. Samples, with typical composition 7.5Li2O–2.5Na2O–20Ga2O3–35GeO2–35SiO2 (mol%), are obtained from the melt-quenching method. The resulting glasses are completely amorphous, but show phase separation, on the nanometer scale, deriving from liquid–liquid phase separation in the melt. Nanocrystallization of gallium oxide, in its metastable gamma phase, is thermally activated inside the matrix at about 615 °C. Treatment at higher temperature causes the formation of LiGa5O8 polymorph by Li ion diffusion from the surrounding matrix to the nanocrystals. In a second step, a further increment of temperature induces an order-to-disorder LiGa5O8 change that finally dissociates causing the formation of beta-Ga2O3. Neutron scattering, X-ray diffraction analysis, differential scanning calorimetry, and transmission electron microscopy studies have been performed so as to assess nucleation and crystal growth mechanisms. Parallel to morphological studies, we also present optical response of these systems, characterized by a strong UV-excited blue luminescence due to intrinsic defects and its dependence on thermal treatments. - See more at: http://www.european-mrs.com/2015-fall-symposium-w-european-materials-research-society#sthash.pRj5G4Gf.dpuf
Si
abstract + slide
glassceramic; gallium oxide; XRD; phase transformation
English
E-MRS 2015 – European Materials Research Society Fall Meeting
Lorenzi, R., Azarbod, A., De Trizio, L., Ignat'Eva, E., Sigaev, V., Golubev, N., et al. (2015). Phase separation and optical properties of nanostructured oxide-in-oxide Ga2O3-containing germanosilicate glasses. Intervento presentato a: E-MRS 2015 – European Materials Research Society Fall Meeting, Warsaw.
Lorenzi, R; Azarbod, A; De Trizio, L; Ignat'Eva, E; Sigaev, V; Golubev, N; Paleari, A
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/92360
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