We have grown InN films directly on sapphire (0001) substrates by pulsed laser deposition (PLD), without the need for any buffer layers. We have found that the growth temperature and the laser intensity exert a large influence on the crystalline quality of the InN films. We have also found that the electrical properties and the crystalline quality are improved with increasing film thickness. FWHM values for InN 0002 and 11 (2) over bar4 X-ray rocking curves for a 1.5-mu m-thick InN film were as small as 0.14 degrees and 0.26 degrees, respectively. The electron mobility and carrier density in the film were 1300 cm(2)/Vs and 3.0 x 10(18) cm(-3), respectively. The fact that PLD direct growth of InN on sapphire substrates leads to formation of epitaxial material is quite consistent with the theoretical prediction from first principles calculations and is probably due to the enhanced surface migration of the InN precursors. (C) 2008 Elsevier B.V. All rights reserved.