EARLY STAGES OF RAMIFIED GROWTH IN QUASI-2-DIMENSIONAL ELECTROCHEMICAL DEPOSITION

I have measured the early stages of the growth of branched metal aggre gates formed by electrochemical deposition in very thin layers. The gr owth rate of spatial Fourier modes is described qualitatively by the r esults of a linear stability analysis [D.P. Barkey, R.H. Muller, and C .W. Tobias, J. Electrochem. Sec. 136, 2207 (1989)]. The maximum growth rate is proportional to (Ilc)(delta) where I is the current through t he electrochemical cell, c the electrolyte concentration, and delta=1. 37+/-0.08. Differences between my results and the theoretical predicti ons suggest that electroconvection in the electrolyte has an influence on the instability leading to ramified growth.