Bulk-quantity wurtzite structured gallium nitride nanobelts have been synthesized on a large area of the silicon substrate by a reaction of gallium/gallium oxide and ammonia using nickel and boron oxide as catalysts. The widths of the nanobelts are in the range from 100 nm to 1 mum and the thickness is about 1/10 of the width. They usually have an uneven thickness and jagged side edges that are approximately symmetric to the growth direction. The growth directions of the nanobelts are not the same, but the [001] direction is always perpendicular to the belt plane. (C) 2002 Elsevier Science B.V. All rights reserved.