A SYSTEMATIC ELECTROCHEMICAL STUDY OF DIAMOND ELECTRODES WITH VARIOUS BORON DOPING CONCENTRATIONS

摘要

Electrochemical behavior of a set of microwave plasma assisted chemical vapor deposition (MWCVD) grown polycrystalline diamond electrodes showing a wide boron concentration range of 8 X10~(17) to 9 X 10~(21) B-cm~(-3), has been investigated in neutral and acidic solutions. Their electrochemical behavior was studied. It was found that the activity of each electrode was mainly controlled by its doping level and more precisely by the occurrence and behavior of its impurity band, which could supply either electrons or holes to the electrolyte through hopping between its electronic levels. Very high cathodic and anodic currents were obtained when metallic conductivity reached the impurity band (in the case of B concentration > 10~(2-) B-cm~(-3)). The efficiency of the electrochemical reactions was interpreted from the Raman spectra of the electrodes.