Structure formation in diffusional growth and dewetting

The morphology diagram of possible structures in two-dimensional diffusiona l growth is given in the parameter space of undercooling Delta versus aniso tropy of surface tension epsilon. The building block of the dendritic struc ture is a dendrite with a parabolic tip, and the basic element of the seawe ed structure is a doublon. The transition between these structures shows a jump in the growth velocity. We show the analogy of diffusional growth with dewetting patterns of a fluid film on a substrate. We also describe the st ructures and velocities of fractal dendrites and doublons destroyed by nois e. The extension of these results to three-dimensional growth is briefly di scussed. (C) 2000 Elsevier Science B.V. All rights reserved.