Effect of Ga on the structure of Ge–Se–Ga glasses from thermal analysis, Raman and XPS measurements

Maeda, Kouji; Sakai, Takeyasu; Sakai, Kentaro; Ikari, Tetsuo; Munzar, M.; Tonchev, D.; Kasap, S. O.; Lucovsky, G.

doi:10.1007/s10854-007-9238-0

Cited by 25 publications

(16 citation statements)

References 11 publications

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“…Ge and Ga atoms were found to be fourfold coordinated [21,31,[33][34][35]. The average coordination number of selenium atoms was found to be higher than two in several studies [21,32,34], but twofold coordinated Se-atoms were reported by Golovchak et al [33]. The chemically ordered network model seems to be more or less valid in these compounds as reported in Refs.…”

Section: Introductionmentioning

confidence: 61%

“…Ge-Ga-Se systems were investigated by several groups and methods, for example by Raman scattering [31][32][33][34], X-ray diffraction and IR spectroscopy [35], X-ray photoelectron spectroscopy (XPS) [32,33], EXAFS [33], NMR spectroscopy [34], neutron diffraction and EXAFS measurement combined with reverse Monte Carlo (RMC) simulation technique [21]. Ge and Ga atoms were found to be fourfold coordinated [21,31,[33][34][35].…”

Section: Introductionmentioning

confidence: 99%

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Local motifs in GeS2–Ga2S3 glasses

Pethes

Nazabal

Chahal

et al. 2016

Journal of Alloys and Compounds

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The structure of (GeS 2 ) 0.75 (Ga 2 S 3 ) 0.25 and (GeS 2 ) 0.83 (Ga 2 S 3 ) 0.17 glasses was investigated by Raman scattering, high energy X-ray diffraction and extended X-ray absorption fine structure (EXAFS) measurements at the Ga and Ge K-edges. The reverse Monte Carlo simulation technique (RMC) was used to obtain structural models compatible with diffraction and EXAFS datasets. It was found that the coordination number of Ga is close to four. While Ge atoms have only S neighbors, Ga binds to S as well as to Ga atoms showing a violation of chemical ordering in GeS 2 -Ga 2 S 3 glasses. Analysis of the corner-and edge-sharing between [GeS 4/2 ] units revealed that about 30% of germanium atoms participate in the edge-shared tetrahedra.

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Section: Introductionmentioning

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Local motifs in GeS2–Ga2S3 glasses

Pethes

Nazabal

Chahal

et al. 2016

Journal of Alloys and Compounds

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“…The two peaks observed at ~200 and ~215 cm -1 are attributed to A 1 symmetric stretching mode of corner linked GeSe 4/2 tetrahedra and to A 1 c breathing vibration mode (also called companion mode) likely related to symmetric vibration mode of GeSe 4/2 tetrahedra connected by edge [32][33][34]. The bands related to germanium and gallium structural units certainly overlap due to close atomic weights of these elements and amorphous character of the matrix leading to broad vibration modes [18]. With introduction of Ga, the maximum of the dominant band of Raman spectra slightly shifts to higher frequency from 195 cm -1 to 197 cm -1 .…”

Section: Comparison With Raman Spectroscopy Analysismentioning

confidence: 98%

Short range order in Ge-Ga-Se glasses

Pethes

Chahal

Nazabal

et al. 2015

Journal of Alloys and Compounds

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International audienceShort range order of glassy Ge20Ga10Se70 and Ge20Ga5Se75 was investigated by neutron diffraction and extended X-ray absorption fine structure spectroscopy (EXAFS) at Ge, Ga and Se K-edges. For each composition large scale structural models were obtained by fitting simultaneously the four experimental datasets in the framework of the reverse Monte Carlo simulation technique. It was found that both Ge and Ga are predominantly fourfold coordinated. The quality of the fits was strongly improved by introducing Ge-Ga bonding. Models giving the best agreement with experimental data show that Ga has a complex effect on the Ge-Se host matrix: i) it enters the covalent network by forming Ga-Ge bonds ii) by decreasing the number of Se atoms around Ge, it contributes to the formation of Se-Se bonds, which may explain the higher solubility of lanthanide ions iii) the average coordination number of Se increases due to the Ga-Se ‘extra’ bonds. The higher average coordination of the network may be responsible for the increase of Tg upon adding Ga to Ge-Se glasse

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“…Moreover, many properties such as a high refractive index, low-loss transmission in the mid-IR, and low phonon energies of chalcogenide glasses are desirable characteristics for a potential material for use in integrated photonics. We have previously examined various Er-doped Ga-Ge-Se chalcogenide glasses [1][2][3]. There were quenched from melt materials.…”

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confidence: 99%

“…The latter value is similar to our result, though our film samples do not contain Ge atoms. The Er 3+ ion is surrounded by [GaSe 4/2 ] − substructures in the Ga-Ge-Se glasses [9]. Then the luminescence lifetimes are depended on the Ga and Se concentration, and independent of the Ge.…”

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confidence: 99%

Photoluminescence properties of erbium‐doped amorphous gallium‐germanium‐selenium films fabricated by RF sputtering

Imai¹,

Maeda

Fujita

et al. 2009

Phys. Status Solidi (c)

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Chalcogenide glasses have various useful features for optical devices such as a high refractive index, low‐loss transmission in the mid‐IR, and low phonon energies. The fabrication of thin films is important for use in waveguide applications and integrated photonics. In this work, we report the properties of vacuum deposited films of gallium‐germanium‐selenium glasses onto fused silica substrates by an RF magnetron sputtering technique (RF electric power of 40‐250 W and growth rate of 0.01‐2.1 μm/min). The concentration of Er3+ ions is controlled by the number of sintered Er2S3 small plates on a target. Samples are shown to be in an amorphous‐like state as measured by X‐ray diffraction experiments. Film thicknesses are proportional to the RF sputtering power and sputtering time. The compositions of films obtained from energy dispersive X‐ray (EDX) analysis. There are much dependent on the condition of the sputtering target, for example whether the target is in the bulk or powder‐state. Photoluminescence (PL) spectrum, intensity, and lifetime at 1550 nm band are measured by excitation from a 973 nm laser. The PL band of the films has a similar shape to those of bulk glasses. The PL intensity increased with the RF electric power. The PL lifetime at the 1550 nm band of the film is about 1.8‐2.6 ms; the latter values are similar to those of bulk samples. The results show that the RF sputtering is a potential method of fabrication for Er‐doped GeGaSe thin films. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Effect of Ga on the structure of Ge–Se–Ga glasses from thermal analysis, Raman and XPS measurements

Cited by 25 publications

References 11 publications

Local motifs in GeS2–Ga2S3 glasses

Local motifs in GeS2–Ga2S3 glasses

Short range order in Ge-Ga-Se glasses

Photoluminescence properties of erbium‐doped amorphous gallium‐germanium‐selenium films fabricated by RF sputtering

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