AlN single crystal platelets up to 2 x 3 mm 2 and needles I mm in diameter and 3 mm in length were successfully grown by directly heating the source materials with microwaves. The process temperature was over 2000degreesC and the pressure was kept constant at 910 Torr. The growth rate was typically 300 mum h(-1) in the c-direction. An emission around 5.5eV was observed in the photoluminescence spectrum probably caused by magnesium impurity. The dislocation density was low, 6 x 103 cm(-2), as determined by both synchrotron white beam X-ray topography and etching in molten potassium hydroxide sodium hydroxide eutectic alloy. Etching produced hexagonal pits and hexagonal hillocks on the Al- and N-polar surfaces, respectively. Raman spectra, X-ray topograph, and etch pit densities demonstrate that the crystals have good structural quality. (C) 2003 Elsevier B.V. All rights reserved.