COMPARISON BETWEEN GAS-PHASE AND ELECTROCHEMICAL DEPOSITION OF COPPER ON PT(100)-(1X1) AND PT(100)-HEX-RO.7-DEGREES

Cyclic voltammetry (CV), Auger electron spectroscopy (AES) and low-energy electron diffraction (LEED) have been used in a detailed study of copper deposition on Pt(100). For copper films synthesised both in ultra-high vacuum (UHV) and in the electrochemical cell, the potential and overall shape of the electrochemical stripping peaks depends critically upon the initial crystallography of the Pt(100) substrate. It is found that the Pt(100)-(1 x 1) surface gives rise to a monolayer desorption peak at significantly more negative potentials than the same peak derived from the deconstructed hex phase. Furthermore, although Pt(100)-(1 x 1) generates a series of discrete multilayer desorption peaks, the voltammetry of multilayer copper deposited onto a Pt(100)-hex-R0.7 degrees surface produces much broader stripping peaks. These results are consistent with a greater degree of surface disorder in the deconstructed hex surface relative to the (1 x 1) phase and may also explain the wide variety of different voltammetric responses reported for this metal adsorption system by different workers.