Step Kinetics Dependent on the Kink Generation Mechanism in Colloidal Crystal Growth

Abstract

Nucleation and growth of two-dimensional (2D) islands on a terrace are the dominant growth mechanisms of colloidal crystals whose particle interaction is attractive. The step velocity, vstep, of the 2D islands at various area fractions, ϕarea, and polymer concentrations, Cp, has been investigated. At low Cp (weak attractive interaction between particles), there is a nearly linear relationship between vstep and ϕarea, whereas it is parabolic for high Cp (strong attraction). Depending on the Cp, two manners of kink generation at a step are observed: 1D nucleation under strong attraction and association of mound formation under weak attraction. As a result of mound formation, abundant kinks are created at steps, resulting in a linear relationship between vstep and ϕarea, whereas the relationship is parabolic for step propagation associated with 1D nucleation. Though the kink site is the most favored site for particles to be incorporated into crystals, weak attractive interaction makes the step front site an ...