We propose the use of flow-rate modulation epitaxy (FME) to improve the size uniformity of InP nanopyramids formed with selective-area growth. InP nanopyramids with square base were successfully obtained under optimum growth conditions. High growth temperature enhances the formation of {1 1 1} facets, resulting in improvement of shape uniformity. InP nanopyramids formed by FME exhibited good size uniformity in comparison with those formed by conventional organometallic vapor-phase epitaxy. (C) 2002 Elsevier Science B.V. All rights reserved.