In this study, a detailed investigation of the growth of vertically oriented and surface mounted InP nanowires has been carried out. They were grown by metal organic vapor phase epitaxy on semi-insulating <111> B-oriented InP wafers using An nanoparticle-assisted vapor-liquid-solid growth technique. The proper conditions for the stable nanowire growth were obtained by systematic variation of the pre-growth annealing and the growth temperatures and were found to be 540 and 440 degreesC, respectively. The variation in the length of the nanowires was also studied as a function of time. Transmission electron diffraction studies carried out on the single nanowires revealed the <111> growth direction with the presence of rotational twin structures, the axis of rotation being the growth direction. Analysis of the high-resolution transmission electron microscopic images shows that the orientation and kinks on the nanowires were controlled by the distribution of these twin structures. (C) 2004 Elsevier B.V. All rights reserved.