Aluminium nitride was grown on c-plane sapphire by metal organic vapor phase epitaxy (MOVPE) at temperatures of 1070 degrees C by a pulsed growth method and in continuous growth mode at temperatures up to 1270 degrees C. For both methods the V/III ratio was varied and different approaches for the growth start were investigated. The crystal quality was mainly characterized by scanning electron microscopy and high resolution X-ray diffraction which show edunusualline shape for certain samples. Both growth methods enabled the growth of more than 1 mu m thick, atomically flat, Al-polar layers with edge type dislocation densities in the order of 3 x 10(10) cm(-2) for pulsed samples and 5 x 10(9) cm(-2) for conventionally grown samples. (C) 2013 Elsevier B. V. All rights reserved.