Initial stages of electrodeposition of Tl, Cd and Cu on n-Si(111) from sulfate electrolyte solutions are studied using cyclic voltammetry and chronoamperometry. Capacitance measurements in metal ion free solutions were used to determine the flat band potential of n-Si. Results show that the relative position of the metal equilibrium potential with respect to the substrate flat band potential influences significantly nucleation and growth kinetics. Within appropriate potential ranges the initial deposition kinetics corresponds to a model including progressive nucleation and diffusion controlled cluster growth. Nucleation rate and the number of atoms in the critical nucleus are determined from the analysis of current transients at different overpotentials. Results are compared with data obtained previously for electrochemical nucleation of these metals on other semiconductors and foreign metal substrates.

Electrodeposition; Nucleation; Crystal growth; Semiconductors; Flat band potential