Doping level influence on chemical surface of diamond electrodes

The modification of surface bond termination promoted by the doping level on diamond electrodes is analyzed. The films were prepared by hot filament chemical vapor deposition technique using the standard mixture of H2/CH4 with an extra H2 flux passing through a bubbler containing different concentrations of B2O3 dissolved in methanol. Diamond morphology and quality were characterized by scanning electron microscopy and Raman scattering spectroscopy techniques while the changes in film surfaces were analyzed by contact angle, cyclic voltammetry and synchrotron X-ray photoelectron spectroscopy (XPS). The boron-doped diamond (BDD) films hydrophobicity, reversibility, and work potential window characteristics were related to their physical properties and chemical surface, as a function of the doping level. From the Mott–Schottky plots (MSP) and XPS analyzes, for the lightly (1018 cm−3) and highly (1020 cm−3) BDD films, the relationship between the BDD electrochemical responses and their surface bond terminations is discussed.

► Two boron doped diamond films were grown with different doping levels.
► Different electrochemical response between the samples was observed.
► There was a direct relationship between the measurements of XPS, electrochemical and contact angle.
► The doping process results in different chemical terminations.
► The doping process affects the band diagram result in NEA or PEA.