STRUCTURAL, SPECTROSCOPIC, AND ELECTROCHEMICAL CHARACTERIZATION OF BORON-DOPED DIAMOND FILMS FROM DIFFERENT PROVENANCES

Morphological, spectroscopic, and electrochemical aspects of boron-dop ed diamond (BDD) films grown on silicon surfaces originating from thre e different laboratories have been examined by atomic force microscopy (AFM), Raman scattering, Auger electron spectroscopy, and cyclic volt ammetry in polyethylene oxide LiClO4 electrolytes in ultrahigh vacuum. All specimens displayed AFM images characteristic of diamond and Rama n spectra consistent with a wide range of boron concentrations (10(19) to 10(21) B atom/cm(3)), with no evidence for the presence of gross g raphitic impurities. The cyclic voltammetry of two of the specimens (d enoted as GV2 and CWRU), however, showed features at potentials positi ve to lithium bulk deposition attributed to lithium-ion intercalation/ deintercalation phenomena in non-diamond carbon present as a surface i mpurity, perhaps at the grain boundaries. This finding is consistent w ith earlier results for a specimen of type GV2 in aqueous electrolytes [Vinokur et al., J. Electrochem. Sec., 143, L238 (1996)], for which r ates of heterogeneous electron transfer for certain redox couples were found higher than those for nominally clean BDD surfaces.