Date Approved


Embargo Period


Document Type


Degree Name

Ph.D. Doctor of Philosophy in Materials Science and Engineering


Physics and Astronomy


College of Science & Mathematics


Jeffrey Hettinger, Ph.D.

Committee Member 1

Wei Xue, Ph.D.

Committee Member 2

Lei Yu, Ph.D.

Committee Member 3

Samuel Lofland, Ph.D.


Electrochemistry, Electrode Coatings, Neurostimulation electrode, Platinum Group Metal Oxides, Reactive Magnetron Sputtering, Thin Film


Metallic oxides; Coatings


Materials Science and Engineering


In this dissertation, thin film single, binary, and ternary metal oxides of iridium (Ir), ruthenium (Ru), rhodium (Rh), and palladium (Pd) were synthesized for use as electrode/microelectrode coatings for neural interfacing applications using DC reactive magnetron sputtering. Synthesis conditions which enhanced the electrochemical properties of films as measured by cyclic voltammetry and electrochemical impedance spectroscopy in a phosphate buffered saline solution of the single metal oxides were identified to be 30 mTorr working pressure, 20% oxygen partial pressure, and cathode power densities ≤ 4.9 W/cm2. These parameters were then used to develop the binary and ternary metal oxide films.

The binary metal oxides studied included Ir(1-x)Mx where M = Pd, Rh, Ru, and the ternary metal oxides studied included Ir(1-x-z)MxMz’, where M,M´ = Pd, Rh, and Ru. The binary metal oxide concentrations which produce robust microstructures and exceptional electrochemical performance have been identified to be x ≥ 0.5 for Ir(1-x)RhxOy, x ≥ 0.34 for Ir(1-x)RuxOy, and x ≥ 0.14 for Ir(1-x)PdxOy. Similar compositional ranges have been identified for the ternary metal oxides and include x ≥ 0.16 and z ≥ 0.05 for Ir(1-x-z)PdxRuzOy, x ≥ 0.13 and z ≥ 0.04 for Ir(1-x-z)PdxRhzOy, and x ≥ 0.2 and z ≥ 0.14 for Ir(1-x-z)RuxRhzOy.