Electrochemical behavior of thin Ta3N5 semiconductor film

Tantalum nitride (Ta3N5) thin film is investigated as a visible light-driven photoelectrode material. The photoelectrochernical properties of the material are investigated on the basis of cyclic voltammograms and current-time curves, and the conduction and valence band edges of Ta3N5 are determined from the photocurrent voltage response. The potentials of the conduction and valence bands are found to be satisfactory for the reduction of H+ to H-2 and the oxidation of H2O to O-2. Anodic photocurrent associated with the oxidation of water is obtained under visible-light irradiation, although the Ta3N5 itself undergoes simultaneous oxidation. Through sustained photoinduced redox cycling on the Ta3N5 electrode in aqueous Fe(CN)(6)(3-)/Fe(CN)(6)(4-) solution, Ta3N5 thin film is demonstrated to function as a stable electrode for generating electric current under visible light.