Temperature dependence of Raman spectra of the quartz- and rutile-types of GeO 2

Mernagh, Terrence P.; Liu, Lin-gun

doi:10.1007/s002690050012

Cited by 47 publications

(48 citation statements)

References 16 publications

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“…3) that the annealed sample contains GeO6/2 bonding structures with a volume fraction of 0.5 -1 %, provided that the high density unit is completely converted to hexagonal-like GeO4/2 units. This small concentration may be consistent with the un-detection of a related Raman-scattering peak at 700 cm -1 of the tetragonal GeO2 crystal [41]. The optical and ESR results shown in Figs.…”

Section: Photo-induced Changesupporting

confidence: 83%

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Photo-induced phenomena in GeO2 glass

Terakado

Tanaka

2006

Journal of Non-Crystalline Solids

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Photo-induced changes in GeO2 glass have been studied in optical and structural properties. Band-gap excitation gives rise to modifications in mid-gap optical absorption and photo-luminescence spectrum. It also produces electron-spin signals at g ≃ 1.995 and 2.008.Raman-scattering spectrum becomes sharper, x-ray diffraction patterns show disappearance of a crystalline peak, and illuminated surfaces expand. These observations can be accounted for by assuming bond transformations from rutile-like to defective quartz-like structures and/or from small to large rings. These photo-induced changes in GeO2 are comparatively discussed with those in SiO2 and GeS2.

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Section: Photo-induced Changesupporting

confidence: 83%

“…It is also known that nano-crystalline Ge gives a Raman-scattering peak at 300 cm -1 [25] and the two crystalline forms (described in 4.1.) of GeO2 produce peaks at 440 cm -1 and 700 cm -1 [41], but no related traces can be pointed out in the present spectra.…”

contrasting

confidence: 72%

Photo-induced phenomena in GeO2 glass

Terakado

Tanaka

2006

Journal of Non-Crystalline Solids

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“…For 1 week of reaction time, the vibrational bands assigned to quartz-type GeO 2 are still present and the strongest band located at ∼443 cm -1 can be assigned to Ge-O-Ge symmetric stretching. 13 For 2 weeks of reaction time, new vibrational bands appear, suggesting a structure that is consistent with adamantane-like Ge 4 S 10 4-units. …”

Section: Resultsmentioning

confidence: 98%

Synthesis and Characterization of the Thiogermanic Acids H₄Ge₄S₁₀ and H₂Ge₄S₉

et al. 2003

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The synthesis and structure of the thiogermanic acids H4Ge4S10 and H2Ge4S9 are reported. A novel preparation method consisting of reacting germanium oxide with liquid hydrogen sulfide containing a trace amount of water is used to form Ge4S104-ions. Evaporating the hydrogen sulfide solution at room temperature leaves an unstable H4Ge4S10·xH2O product. The stoichiometry and structure of the thermally stable anhydrous phase are dependent on reaction time. An H4Ge4S10 product with an adamantane-like cage structure is obtained at shorter reaction times. Longer reaction times produce an H2Ge4S9 product with a more complex cage unit, a higher symmetry unit cell, and increased thermal stability. Raman, infrared, powder X-ray diffraction, and thermogravimetric data are reported for both structures.

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“…With increasing temperature, the Raman bands of the rutile-like polymorph transform to the α-quartz-like spectrum at ≃ 1313 K [31] while the Raman bands of the α-quartz-like polymorph show a nonlinear shift with increasing T. Madon et al [31] observed a shift of −0.01 cm −1 /K for the bands in the low frequency region and −0.024 cm −1 /K in the mid-and high-frequency regions. For the rutile polymorph, the Raman bands above 600 cm −1 exhibit nonlinear shifts to lower wavenumbers whereas the 173 cm −1 band exhibits a shift to higher wavenumbers with increasing T [71]. In addition Mernagh and Liu [71] detect (by deconvolution) splitting of the A 1g mode (701 cm −1 ) of the rutile-like polymorph with a new band observed at 684 cm −1 .…”

Section: Raman Spectroscopymentioning

confidence: 95%

The structure of amorphous, crystalline and liquid GeO₂

Micoulaut

Cormier

Henderson

2006

J. Phys.: Condens. Matter

228

252

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Abstract. Germanium dioxide (GeO 2 ) is a chemical analogue of SiO 2 . Furthermore, it is also to some extent a structural analogue, as the low and high-pressure short-range order (tetrahedral and octahedral) is the same. However, a number of differences exist. For example, the GeO 2 phase diagram exhibits a smaller number of polymorphs, and all three GeO 2 phases (crystalline, glass, liquid) have an increased sensitivity to pressure, undergoing pressure induced changes at much lower pressures than their equivalent SiO 2 analogues. In addition, differences exist in GeO 2 glass in the medium range order, resulting in the glass transition temperature of germania being much lower than for silica. This review highlights the structure of amorphous GeO 2 by different experimental (e.g., Raman and NMR spectroscopy, neutron and x-ray diffraction) and theoretical methods (e.g., classical molecular dynamics, ab initio calculations). It also addresses the structure of liquid and crystalline GeO 2 that have received much less attention. Furthermore, we compare and contrast the structural differences between GeO 2 and SiO 2 , as well as, along the GeO 2 − SiO 2 join. It is probably a very timely review as interest in this compound, that can be investigated in the liquid state at relatively low temperatures and pressures, continues to increase.

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Temperature dependence of Raman spectra of the quartz- and rutile-types of GeO 2

Cited by 47 publications

References 16 publications

Photo-induced phenomena in GeO2 glass

Photo-induced phenomena in GeO2 glass

Synthesis and Characterization of the Thiogermanic Acids H₄Ge₄S₁₀ and H₂Ge₄S₉

The structure of amorphous, crystalline and liquid GeO₂

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Temperature dependence of Raman spectra of the quartz- and rutile-types of GeO 2

Cited by 47 publications

References 16 publications

Photo-induced phenomena in GeO2 glass

Photo-induced phenomena in GeO2 glass

Synthesis and Characterization of the Thiogermanic Acids H4Ge4S10 and H2Ge4S9

The structure of amorphous, crystalline and liquid GeO2

Contact Info

Product

Resources

About

Synthesis and Characterization of the Thiogermanic Acids H₄Ge₄S₁₀ and H₂Ge₄S₉

The structure of amorphous, crystalline and liquid GeO₂