UNDERPOTENTIAL DEPOSITION OF CU ON BORON-DOPED DIAMOND THIN-FILMS

The deposition of copper on boron-doped diamond thin-film electrodes w as investigated, Three kinds of boron-doped diamond films were studied : a film deposited on a silicon wafer, a second grown on a tungsten su bstrate. and a third, similar to the first, but surface-amorphized (bo mbarded) by ion beam irradiation. The films were investigated by a num ber of techniques. Linear potential sweep experiments in 0.1 M H2SO4 0.001 M CuSO4 solution showed that, besides the peak due to bulk copp er deposition, a ''prewave'' peak is present in the voltammogram of th e first two electrodes and not in the third one. An electrochemical ac tivation at negative potential was imperative for the appearance of th e ''prewave'' peak. The amount of copper involved was less than 2% of a monolayer. The comparison between spectroscopic and electrochemical investigations leads to the interpretation that the ''prewave'' peak c orresponds to an underpotential deposition of Cu on graphitic inclusio ns in the diamond electrode, or along the grain boundaries, probably b y intercalation.