New understandings for two-dimensional nucleation (II)

Abstract

Foreign particles adsorbed on flat crystal surfaces can serve as two-dimensional nucleation centers for the growth. In this paper, a kinetic model for heterogeneous two-dimensional nucleation is presented. The free energy barrier of two-dimensional nucleation in the presence of foreign particles and the kinetics for the nucleation and growth are examined theoretically. It follows that the contact angle, size and density of adsorbed foreign particles play a crucial role in controlling the 2D nucleation barrier and growth kinetics. The theory can be successfully applied to interpret experiments of dislocation-free growth.