Physico-chemical characterization of Ta2O5 thin films/electrolyte junctions

An analysis of the electronic properties of Ta₂O₅/electrolyte junction is reported for thin film( les 14 nm) grown on tantalum in acidic electrolyte. The investigation is carried out by the synergetic use of three techniques: Photocurrent Spectroscopy (PCS), Electrochemical Impedance Spectroscopy (EIS) and Differential Admittance (DA) measurements. PCS is a non destructive optical technique based on the analysis of the electrochemical response (photocurrent or photopotential) of the electrode/electrolyte interface under irradiation with photons of suitable energy. PCS can provide information on the energetic of metal/oxide/electrolyte interfaces (flat band potential determination, conduction and valence band edges location). EIS allows to model the electrochemical behaviour of the oxide/electrolyte interface and AD measurements allow to get information on the tantalum grown in the investigated conditions.