Two-Dimensional Growth of Surface Nuclei

The growth of a surface nucleus is achieved by either surface or bulk diffusion to the step or kink site at the edge of the growing nucleus. For the liquid phase, bulk diffusion is more important [3], giving a surface growth rate, 

This 2-D growth rate must be compared to the surface nucleation rate J. To make this comparison, the time between two nucleation events, on a surface of area, A, is compared to the time necessary 

This corresponds to the crossover point between mononuclear and polynuclear layer growth. At this crossover point, the crystal growth rate is given by 

FIGURE 6.13 Two-dimensional growth of sxuface nuclei by (a) mononuclear growth and fb) polynuclear growth models. Redrawn, with permission from Dirksen and Ring [4a]. 

At supersaturations less than the critical supersaturation ratio for surface nucleation, surface —1-5, layer growth has been experimentally 

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