Raman study of α-quartz-type Ge 1−x Si x O 2 (0 < x ≤ 0.067) single crystals for piezoelectric applications

• Published in: RSC advances 2015, Vol.5 (69), p.55795-55800
• Main Authors: Lignie, Adrien, Hermet, Patrick, Fraysse, Guillaume, Armand, Pascale
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C5RA08051G

As potential candidates for high temperature piezoelectric materials, α-quartz-type Ge 1−x Si x O 2 (0 < x ≤ 0.067) single crystals grown by the flux method were structurally and thermally characterized. When compared to pure α-GeO 2 , room temperature polarized Raman spectra contained additional lines which have been assigned from density functional theory on a α-Ge 0.833 Si 0.167 O 2 solid solution. The results highlight that Si–O–Ge bridges were involved. Moreover, a linear relationship between the wavenumber position of the main A 1 Raman lines and the SiO 2 substitution rate x was also observed. The analysis of the temperature dependence of unpolarized Raman signals of an α-Ge 1−x Si x O 2 phase with x = 0.067 pointed out the high-thermal stability up to 1000 °C of the α-quartz-like structure related to the lack of a libration mode and to the absence of a softening mode with temperature.