Microwave Dielectric Properties and Defect Behavior of xTiO₂-(1-x)SiO₂ Glass

Area of Science:

• Materials Science
• Solid State Physics
• Optoelectronics

Background:

• Titanium dioxide (TiO2) and silicon dioxide (SiO2) glasses are crucial for electronic applications.
• Understanding defect behavior and optical properties is key to optimizing dielectric performance.

Purpose of the Study:

• To investigate the impact of varying TiO2 concentrations (2.9-8.2 mol%) on TiO2-SiO2 glass properties.
• To correlate optical characteristics and defect behavior with microwave dielectric performance.

Main Methods:

• Flame hydrolysis synthesis of TiO2-SiO2 glass specimens.
• UV-vis and near-infrared spectroscopy for optical properties.
• Electron paramagnetic resonance (EPR) and AC impedance spectroscopy for defect analysis.
• Kohlrausch-Williams-Watts (KWW) function and Jonscher power law for data fitting.

Main Results:

• Increased TiO2 content promoted defect generation and migration, leading to higher dielectric losses.
• Decreasing activation energy with higher TiO2 content indicated doubly ionized oxygen vacancies.
• The 8.2TiO2-91.8SiO2 glass exhibited superior microwave dielectric properties (εr = 4.13, Q × f = 57,116 GHz, τf = -4.32 ppm/°C).

Conclusions:

• TiO2 incorporation significantly influences defect dynamics and optical properties in SiO2 glasses.
• Defect behavior, particularly oxygen vacancies, is directly linked to microwave dielectric performance.
• The synthesized 8.2TiO2-91.8SiO2 glass is a promising material for advanced microwave substrate applications.