Advanced RuO₂ Thin Films for pH Sensing Application

Area of Science:

• Materials Science
• Electrochemistry
• Thin Film Technology

Background:

• Ruthenium dioxide (RuO2) is a promising material for electrochemical sensors.
• Optimizing thin film deposition is crucial for enhancing sensor performance.

Purpose of the Study:

• To investigate the effect of magnetron sputtering parameters on RuO2 thin film properties.
• To determine the optimal conditions for achieving high pH sensitivity in RuO2 thin films.

Main Methods:

• Magnetron sputtering (DC and RF) with varying deposition conditions.
• Characterization of surface morphology, composition, crystal structure, and mechanical properties.
• Evaluation of pH performance and sensitivity.

Main Results:

• DC sputtered RuO2 films from an oxide cathode showed higher pH sensitivity (57.37 mV/pH) with improved surface smoothness, density, and hardness.
• RF sputtered films from a metallic cathode had slightly lower sensitivity (56.35 mV/pH) but were rougher, less dense, and softer.
• Higher RuO3 phase content in RF sputtered films correlated with better pH response.

Conclusions:

• DC sputtering from an oxide cathode offers a superior method for fabricating high-performance RuO2 pH sensors.
• Film microstructure and composition significantly influence pH sensing capabilities.
• Further research can explore optimizing RuO3 phase content for enhanced sensor design.