DYNAMIC-SCALING EXPONENTS AND THE ROUGHENING KINETICS OF GOLD ELECTRODEPOSITS

The kinetics of gold electrodeposit toughening was studied at the nano meter level by scanning tunneling microscopy (STM) and by using dynami c-scaling theory. Gold electrodeposits were grown at 100 nm s(-1) from the electroreduction of hydrous gold oxide layers. The following dyna mic-scaling exponents were obtained: alpha(I)=0.90+/-0.06 and beta(I)= 0.31+/-0.08 for L(s)<L(sc), and alpha(II)=0.49+/-0.05 and beta(II)=0.5 1+/-0.08 for L(s)>L(sc), where L(s) is the scale length, and L(sc) is a critical length closely related to the average grain size of the ele ctrodeposit measured from STM imaging. Results from dynamic-scaling an alysis are consistent with a grain surface smoothing mechanism involvi ng surface diffusion of gold atoms.