InN films were grown by metal-organic vapour phase epitaxy (MOVPE). The growth was performed in a MOVPE apparatus with a vertical reactor geometry optimized for the growth of GaN. The reactor geometry is found to cause enhanced cracking of NH3, and the growth rate is limited by the amount of reactive indium in the temperature range of 550-650 degrees C. The grown films are characterized comprehensively. Experimental results indicate that the InN films, grown on sapphire substrates, contain metallic indium and the film surface consist of hexagonal islands. Growth temperature has a strong effect on the surface island size, optical quality and electrical properties of the InN layer. The desorption of nitrogen is assumed to cause the formation of metallic indium above 550 degrees C. (c) 2006 Elsevier B.V. All rights reserved.