Bat-like InN nanostructures were successfully grown on GaN/AlN/Si(1 1 1) substrates using molecular beam epitaxy method. The initial growth behavior and structural properties of InN nanobats were studied from a nanostructural point of view. During the initial stage of the growth, a nucleation process and a shape-decision process took place in which 3-dimensional (3-D) GaN nanoislands and nanorods were formed on AlN initiation layer/Si substrate. This was followed by the independent growth of 3-D InN nanoislands and nanorods. Lateral expansion of the InN nanobats was observed, and the diameter of InN bats then reached a fixed value. (C) 2009 Elsevier B.V. All rights reserved.