We investigated the effect of growth parameters for obtaining high-quality AlN grown directly on sapphire substrates by a hybridized method, derived from simultaneous source supply and conventional migration-enhanced epitaxy. At an optimal growth temperature of 1200 degrees C, AlN was atomically smooth and pit-free, while below and above 1200 degrees C, AlN was rough and with pits, respectively. Surface morphologies also depended on the V/III ratio. Rough surfaces became atomically smooth but then pits appeared, as the V/III ratio increased. The crystallinity revealed by X-ray diffraction changed accordingly. The 600-nm-thick AlN grown under the optimal conditions showed X-ray line widths of as narrow as similar to 43 and similar to 250 arcsec for (0 0 0 2) and (1 0 (1) over bar 2) diffractions, respectively. (C) 2009 Elsevier B.V. All rights reserved.