Hardness, Toughness, and Scratchability of Germanium–Selenium Chalcogenide Glasses

In this work, we investigated the role of ultraviolet (UV) curing on the dielectric constant (k) and molecular structure of a porous organosilicate glass (p-OSG) dielectric with k of approximately 2.5. The dielectric constant was investigated in a fundamental manner by quantifying its polarizability components: electronic, ionic, and dipolar. A method involving the KramersKronig relations was formulated to separate the ionic and electronic polarizabilities. After quantifying the polarizability components, the evolution of the molecular structure with UV curing was investigated by Fourier-transform infrared spectroscopy (FTIR) and x-ray photoelectron spectroscopy (XPS). The results from the molecular structure investigation were used to explain the observed trends in polarizability.

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“…22 Our results for mode I and mixed-mode fracture, presented in another paper, 23 confirm this expectation.…”

Section: Mechanical Propertiessupporting

confidence: 92%

Analysis of Ultraviolet Curing Effect on the Dielectric Constant and Molecular Structure of a Porous Dielectric Film

Smith

Tsui

2010

Journal of Elec Materi

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“…FIGURE 2 | The dependence of the mass density at room temperature ρmass for the GexSe 1− x system on the composition x and mean coordination number n = 2(1 + x). The results from the present work at ≃22°C are compared to those taken from Andonov (1982), Avetikyan and Baidakov (1972), Azoulay et al (1975), Bhosle et al (2012b), Borisova (1981), Feltz et al (1983), Feltz and Lippmann (1973), Guin et al (2002b), Hafiz et al (1993), Ito et al (1988), Loehman et al (1972), Ota et al (1978), Senapati and Varshneya (1995), Sreeram et al (1991b), and Yang et al (2013). The solid (black) curves are drawn as guides for the eye.…”

Section: Glass Synthesis and Characterizationmentioning

confidence: 95%

Topological Ordering and Viscosity in the Glass-Forming Ge–Se System: The Search for a Structural or Dynamical Signature of the Intermediate Phase

et al. 2017

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The topological ordering of the network structure in vitreous Ge x Se 1−x was investigated across most of the glass-forming region (0 ≤ x ≤ 0.4) by using high-resolution neutron diffraction to measure the Bhatia-Thornton number-number partial structure factor. This approach gives access to the composition dependence of the mean coordination number n and correlation lengths associated with the network ordering. The thermal properties of the samples were also measured by using temperature-modulated differential scanning calorimetry. The results do not point to a structural origin of the so-called intermediate phase, which in our work is indicated for the composition range 0.175(8) ≤ x ≤ 0.235(8) by a vanishingly small non-reversing enthalpy near the glass transition. The midpoint of this range coincides with the mean-field expectation of a floppy-to-rigid transition at x = 0.20. The composition dependence of the liquid viscosity, as taken from the literature, was also investigated to look for a dynamical origin of the intermediate phase, using the Mauro-YueEllison-Gupta-Allan (MYEGA) model to estimate the viscosity at the liquidus temperature. The evidence points to a maximum in the viscosity at the liquidus temperature, and a minimum in the fragility index, for the range 0.20 ≤ x ≤ 0.22. The utility of the intermediate phase as a predictor of the material properties in network glass-forming systems is discussed.

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“…[81]) or 11.47 GPa (Ref. [82]) as obtained from sound velocity measurements on GeSe 4 glass. In Fig.…”

Section: Methodsmentioning

confidence: 99%

Pressure-induced structural changes in the network-forming isostatic glassGeSe4: An investigation by neutron diffraction and first-principles molecular dynamics

et al. 2016

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The changes to the topological and chemical ordering in the network-forming isostatic glass GeSe 4 are investigated at pressures up to ∼14.4 GPa by using a combination of neutron diffraction and first-principles molecular dynamics. The results show a network built from corner-and edge-sharing Ge(Se 1/2 ) 4 tetrahedra, where linkages by Se 2 dimers or longer Se n chains are prevalent. These linkages confer the network with a local flexibility that helps to retain the network connectivity at pressures up to ∼8 GPa, corresponding to a density increase of ∼37%. The network reorganization at constant topology maintains a mean coordination number n 2.4, the value expected from mean-field constraint-counting theory for a rigid stress-free network. Isostatic networks may therefore remain optimally constrained to avoid stress and retain their favorable glass-forming ability over a large density range. As the pressure is increased to around 13 GPa, corresponding to a density increase of ∼49%, Ge(Se 1/2 ) 4 tetrahedra remain as the predominant structural motifs, but there is an appearance of 5-fold coordinated Ge atoms and homopolar Ge-Ge bonds that accompany an increase in the fraction of 3-fold coordinated Se atoms. The band gap energy decreases with increasing pressure, and midgap states appear at pressures beyond ∼6.7 GPa. The latter originate from undercoordinated Se atoms that terminate broken Se n chains.

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Hardness, Toughness, and Scratchability of Germanium–Selenium Chalcogenide Glasses

Cited by 113 publications

References 17 publications

Analysis of Ultraviolet Curing Effect on the Dielectric Constant and Molecular Structure of a Porous Dielectric Film

Analysis of Ultraviolet Curing Effect on the Dielectric Constant and Molecular Structure of a Porous Dielectric Film

Topological Ordering and Viscosity in the Glass-Forming Ge–Se System: The Search for a Structural or Dynamical Signature of the Intermediate Phase

Pressure-induced structural changes in the network-forming isostatic glassGeSe4: An investigation by neutron diffraction and first-principles molecular dynamics

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