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Al doped silica glass: investigation of structural response and defect interactions based on crystalline models

  • 0SINTEF Industry, Forskningsveien 1, 0373, Oslo, Norway.
Physical Chemistry Chemical Physics : Pccp +

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January 31, 2025

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January 31, 2025

View abstract on PubMed

Summary

This summary is machine-generated.

Aluminum doping in silica glass increases viscosity by altering the silica network structure, not just by substitution. This leads to oxygen vacancies and potential OH group instability, impacting high-tech material properties.

Area Of Science

  • Materials Science
  • Solid State Chemistry
  • Computational Materials Science

Background

  • High purity quartz glass is crucial for semiconductors and photovoltaics.
  • Aluminum (Al) doping (20-100 ppm) in silica (SiO2) glass increases viscosity.
  • The mechanism behind Al-induced viscosity increase in SiO2 glass is not fully understood.

Purpose Of The Study

  • Investigate the local structural and electronic effects of Al in SiO2.
  • Elucidate the mechanism of viscosity increase in Al-doped silica glass.
  • Correlate computational findings with experimental data.

Main Methods

  • Density Functional Theory (DFT) calculations.
  • Comparison of quartz and cristobalite polymorphs.
  • Analysis of oxygen vacancy formation and Al substitution energetics.
  • Investigation of Al-H2O interactions and OH group stability.

Main Results

  • Al substitution is favored in denser quartz over cristobalite.
  • Oxygen vacancy (Vo) formation is stabilized near Al in both polymorphs.
  • Al does not inherently strengthen the SiO2 network but promotes network reconstruction.
  • Al doping leads to oxygen vacancies and can destabilize OH groups.
  • DFT results align with experimental fluorescence and FT-IR data.

Conclusions

  • Al doping increases SiO2 glass viscosity primarily through structural modifications, not direct strengthening.
  • Al-induced network reconstructions, including oxygen vacancies and potential ring size changes, are key.
  • Al can influence OH group stability, further contributing to viscosity changes.
  • Understanding these mechanisms is vital for optimizing high-purity quartz glass for technological applications.