The selective growth of wurtzite GaN was performed on a (1 1 1)silicon substrate by metalorganic vapor phase epitaxy. By limiting the size of GaN to the area of 0.5 mm x 0.5 mm, a single GaN crystal without cracks was obtained. As a result, the full-width at half-maximum of the (0 0 0 4) X-ray-rocking curve as well as that of the band edge emission were much reduced as compared to the samples grown by a conventional method. (C) 2002 Elsevier Science B.V. All rights reserved.