Atomistic mechanisms and diameter selection during nanorod growth

Abstract

We report in this letter the influence of deposition rate and Ehrlich-Schwoebel barrier (ESB) on the growth process of nanorods. A characteristic radius has been identified, which increases proportional to one fifth power of the ratio of the two-dimensional ESB limited hopping rate of adatoms to the deposition rate. When the radius of the initial island is larger than this characteristic radius, the growth morphology evolves from a taper-like structure to a nanorod with radius equal to the characteristic radius, after some transient layers depending on the steering strength. Otherwise the nanorod morphology can be maintained during the growth, with stable radius being limited by both the radius of the initial island and the three-dimensional ESB. The theoretical predictions are in good agreement with experimental observations of ZnO growth.