Synergistic Use of Electrochemical Impedance Spectroscopy and Photoelectrochemical Measurements for Studying Solid State Properties of Anodic HfO2

Hafnium oxide and Nb doped HfO2 were grown by anodizing sputtering-deposited Hf and Hf-4at.%Nb. Photoelectrochemical characterization was carried out in order to estimate solid state properties such as band gap, flat band potential and electrons internal photoemission threshold energy as a function of thickness and composition of anodic oxides. Impedance measurements were performed in a wide range of electrode potentials in order to study the response of the anodic oxides under anodic and cathodic polarization and to estimate their dielectric constants.