Smart Sensing Multifunctionalities Based on Barium Strontium Titanate Thin Films.

Area of Science:

• Materials Science
• Nanotechnology
• Solid State Physics

Background:

• Advanced sensors are crucial for cyber-physical systems, requiring low power, scalability, and rapid stimulus detection.
• Ferroelectric thin films offer potential for integrated sensor applications due to their unique electrical and optical properties.

Purpose of the Study:

• To fabricate ferroelectric barium strontium titanate (BST) thin films on silicon substrates.
• To characterize the structural, ferroelectric, and optical properties of the BST films.
• To evaluate the performance of BST-based capacitor sensors and their electro-optic capabilities.

Main Methods:

• Magnetron sputtering was used for BST thin film deposition on silicon substrates.
• Structural analysis confirmed a pure perovskite structure.
• Ferroelectric properties, phase transition temperature, optical bandgap, sensor sensitivity, and electro-optic coefficient were measured.

Main Results:

• BST films exhibited a remnant polarization of 2.4 μC/cm², a phase transition at 31.2 °C, and an optical bandgap of 3.58 eV.
• Capacitor-based sensors demonstrated high sensitivity (0.10 mV·Pa⁻¹) and stability over 1000 cycles.
• The electro-optic coefficient (r_eff) was 83.5 pmV⁻¹, significantly higher than LiNbO₃.

Conclusions:

• BST thin films are a promising material for developing highly sensitive and scalable sensors.
• The demonstrated electro-optic properties open possibilities for optical manipulation and integration in photonic devices.
• CMOS-compatible fabrication of BST films enables on-chip integration with diverse electronics for advanced cyber-physical applications.