Vapor-liquid-solid (VLS) growth of GaN nanowires was performed and GaN/A1N double buffer layer was employed to minimize the lattice mismatch between GaN nanowires and Si substrates. GaN nanowires grown on GaN/A1N/Si substrates showed the formation of straight nanowires with similar to 50-100 nm diameter, while those grown on bare Si wafers showed formation of tangled nanowires with non-uniform diameters. High-resolution transmission electron microscopy (HRTEM) analyses on the GaN nanowires grown on GaN/A1N/Si showed high crystallinity with [10-1] crystal growth direction. Furthermore, GaN nanowires grown on GaN/AIN/Si showed high intensity blue emission and almost negligible yellow luminescence. (c) 2005 Elsevier B.V. All rights reserved.