Key points are not available for this paper at this time.
Oriented attachment is the key: Single crystalline ZnO nanorods with lengths up to 500 nm could be prepared in a stepwise manner from quasi-spherical nanoparticles. Only after the formation of pearl-chain-like structures (left), do the aggregated particles fuse upon heating to form nanorods (center and right).
Pacholski et al. (Tue,) studied this question.