Large-scale hexagonal GaN nanobelts and nanowires were synthesized by direct reaction of milled Ga2O3 powders with flowing ammonia at 1000 degreesC. X-ray diffraction, scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray were used to characterize the structures, morphologies and compositions of the samples. The results show that those GaN nanobelts and nanowires are single crystals with hexagonal structure. The simple method presented here demonstrates that GaN nanobelts and nanowires can be grown on a large scale without using templates or catalysts. (C) 2002 Elsevier Science B.V. All rights reserved.