Growth law of step bunches induced by the Ehrlich-Schwoebel effect in growth

We study growth law of step bunches formed in growth due to the Ehrlich-Sch woebel effect by using a one-dimensional step flow model. We neglect evapor ation of adatoms and assume that the repulsive interaction potential betwee n steps is given by Al-=x where 4 is the strength of the repulsion and I is the step distance. When the adatoms attach to the step more easily from th e upper terrace than from the lower terrace. an equidistant train of steps is unstable to bunching instability in growth. The terrace width between bu nches increases as the bunches grow via collision and coalescence. Time dep endence of the terrace width is given by L similar to t(beta) with beta app roximate to 1/2. The value of beta is independent of the power of the step interaction potential v. which affects L dependence of the step distance in a bunch. (C) 2001 Elsevier Science B.V. All rights reserved.