  We demonstrate in this report that nanorods can spontaneously grow on the top
of a transient mound when the screening effect is considered in island growth.
The number of the topmost growing layers is defined as the active length, which
decreases as the screening effect is enhanced. It follows that the thickness of
the transient mound underneath the nanorod increases as the square of the
active length, and a smaller active length favors the formation of nanorod.

Mesoscale and Nanoscale Physics;Materials Science