Electrochemical impedance spectroscopy of polycrystalline boron doped diamond layers with hydrogen and oxygen terminated surface

This work is a systematic study of electrochemical impedance spectroscopy of high quality polycrystalline boron doped diamond films with varying boron content (from semiconducting to metallic behavior) and with different surface terminations (hydrogen or oxygen) in aqueous electrolyte solution. The films were grown by microwave plasma enhanced chemical vapor deposition. The concentration of acceptors (NA) was determined from the Mott-Schottky plots and the values were compared with those from neutron depth profiling and Raman spectroscopy. The NA values are in a good agreement across the different techniques, ranging from ca. 1.2 . 10(20) cm(-3) for semiconducting samples up to ca. 2 . 10(21) cm(-3) for heavily doped films with metallic conductivity. The films with hydrogen terminated surface exhibit lower values of both the flat band potentials (Em) and the NA values, compared to the films with oxygen terminated surface. (C) 2015 Elsevier B.V. All rights reserved.