Synthetic Semiconductor Diamond Electrodes: Electrochemical Characteristics of Homoepitaxial Boron-doped Films Grown at the (111), (110), and (100) Faces of Diamond Crystals

Electrode behavior of homoepitaxial (single-crystal) boron-doped diamond films deposited onto differently orientated faces of dielectric diamond single crystals is studied by the electrochemical impedance and potentiodynamic curve methods. It is shown that the acceptor concentration determined from the slope of Mott–Schottky plots decreases, in the epitaxial films grown under the same conditions, in the series: (111) > (110) > (100). This is explained by different intensity of boron incorporation, from gas phase, into differently orientated faces of the diamond crystals during their growth. The rate of electrode reactions in the Fe(CN)₆ ^3–/4– and Ru(NH₃)₆ ^2+/3+ redox systems decreases in the above series, which obeys the earlier found interrelationship between the electrochemical kinetics at diamond electrodes and their doping level.