BaTiO3 doped Na0.5K0.5NbO3 thin films deposited by using eclipse shutter enhanced pulsed laser deposition method

Area of Science:

• Materials Science
• Solid State Physics
• Thin Film Technology

Background:

• Lead-free piezoelectric materials are crucial for sustainable electronic devices.
• BaTiO3 doped Na0.5K0.5NbO3 (BTO-NKN) is a promising lead-free piezoelectric candidate.
• Pulsed Laser Deposition (PLD) is a common technique for thin film fabrication.

Purpose of the Study:

• To investigate the structural, electrical, and electro-mechanical properties of BTO-NKN thin films.
• To improve the surface morphology and density of BTO-NKN thin films using an enhanced PLD (E-PLD) method.
• To evaluate the piezoelectric performance of the optimized BTO-NKN thin films.

Main Methods:

• BTO-NKN thin films were deposited on La0.5Sr0.5CoO3 (LSCO) bottom electrodes with LaAlO3 (LAO) substrates using PLD.
• An eclipse shutter was incorporated into the PLD setup (E-PLD) to enhance film morphology.
• X-ray diffraction (XRD) was used to analyze the crystallographic orientation.
• Surface morphology was characterized by measuring root-mean-square (RMS) roughness.
• Electrical properties (capacitance) and electro-mechanical properties (d33) were measured.

Main Results:

• XRD confirmed high c-axis orientation of BTO-NKN films and LSCO electrodes.
• E-PLD significantly reduced the RMS roughness from 91 nm to 21 nm.
• The enhanced surface morphology resulted in increased film density.
• Optimized BTO-NKN films exhibited a typical capacitance of 1000 pF.
• A piezoelectric coefficient (d33) of 30 pm/N was achieved for films deposited by E-PLD.

Conclusions:

• The E-PLD method effectively improves the surface morphology and density of BTO-NKN thin films.
• Improved film quality leads to enhanced electrical and electro-mechanical properties.
• These lead-free BTO-NKN thin films show potential for piezoelectric applications.