NUCLEATION AND ORDERING OF AN ELECTRODEPOSITED 2-DIMENSIONAL CRYSTAL - REAL-TIME X-RAY-SCATTERING AND ELECTRONIC MEASUREMENTS

We have studied in situ the ordering of a two-dimensional Cu-Cl crysta l electrodeposited on a Pt(111) surface. We simultaneously measured x- ray scattering and chronoamperometric transients during Cu desorption and subsequent ordering of the Cu-Cl crystal. In all cases, the curren t transient occurs on a shorter time scale than the development of cry stalline order. The ordering time diverges with applied potential, con sistent with the nucleation and growth of two-dimensional islands. We see a time-dependent narrowing of the x-ray peak, corresponding to the growing islands. [S0031-9007(98)07423-7].