Orientation-dependent nucleation of GaN on a nano scale-faceted Si substrate in metal-organic vapor-phase epitaxy is reported. On a multiple-faceted Si surface consisting of nanoscale-wide periodic (0 0 1) and (1 1 1) stripe facets which are fabricated on a Si(0 0 1) substrate, the nucleation and incorporation of GaN shows strong selectivity for a (1 1 1) orientation. Growth dominantly proceeds on a (1 1 1) facet with hexagonal phase while negligible nucleation occurs on a (0 0 1) facet in each period. In continued growth, such orientation-dependent selective nucleation results in lateral growth from a (1 1 1) to an adjacent (0 0 1) stripe facet without a masking layer. (c) 2005 Elsevier B.V. All rights reserved.