Morphological control and kinetics in three dimensions for hierarchical nanostructures growth by screw dislocations

Abstract

The precise control and in-depth understanding of the anisotropic crystal screw dislocation growth could yield further optimization of nanomaterial design and broader applications, yet the studies of rational control and kinetics for more complex nanostructures are still insufficient. In this work, by programming synthesis conditions, we achieve a controllable three-dimensional (3D) screw dislocation growth of hierarchical nanostructures, including nanowires, nanoplates, and previously unreported hierarchical hollow nanobelts, via a facile chemical vapor deposition approach. Notably, the screw dislocation growth in nanobelts is confirmed by the clear observations of the stepwise spiral terraces with initial hexagonal to octagonal shapes and the hollow cores in the growth spiral centers, as well as the fundamental Burton-Cabrera-Frank crystal growth theoretical calculations. The formation of the nanowires and nanoplates can be well interpreted by the previously reported screw dislocation growth model, while a new 3D screw dislocation growth model with considering of transition in growth velocities and directions is proposed to interpret the formation of the nanobelts and other potential complex nanostructures. This study not only enriches our understanding of the screw dislocation growth kinetics but also guides us to achieve the precise morphological design and control in nanosynthesis.