Scanning electron microscopy (SEM) images, transmission electron microscopy (TEM) images, and selected-area electron diffraction (SAED) patterns showed that vertically well aligned GaN nanorods with c-axis-oriented crystalline wurzite structures were grown on Si(1 1 1) substrates by using hydride vapor phase epitaxy. The high-resolution TEM (HRTEM) images showed that the crystallized GaN nanorods contained very few defects and that they were consisted of {(1) over bar1 0 0}, {0 0 0 1}, and {(1) over bar 10} facets. The formation mechanisms for the GaN nanorods grown on Si(1 1 1) substrates are described on the basis of the SEM, TEM, SAED pattern, and HRTEM results. (C) 2008 Elsevier B. V. All rights reserved.