Atomic-scale behavior of adatoms in axial and radial growth of GaN nanowires: Molecular dynamics simulations

The effect of the flux ratio of N atoms to Ga atoms on the radial/axial growth of GaN nanowires during molecular-beam epitaxy has been investigated by molecular dynamics simulations. By studying adatoms on a surface during the growth of GaN nanowires, we explore the underlying mechanisms and find that both a preferable adsorption surface for N and Ga adatoms and the desorption of N adatoms play a key role for such axial/radial growth. These observations on the atomic scale are crucial for understanding the self-induced growth of GaN nanowires in general as well as for achieving their desired morphology under different growth conditions.