ZnO nanowires were fabricated on the amorphous diamond thin layer on silicon substrates using thermal chemical vapor transport and condensation (CVTC) without any metal catalysts. The remarkable enhancement of the field emission of the nanocomposites by ZnO nanowires covered amorphous diamond was found compared to that of the intrinsic amorphous diamond, suggesting the probability of decorating amorphous diamond by fabricating one-dimensional nanostructures on its surface, which could largely improve the field emission by modifying surface microstructures. Associated with surface chemical reactions, a vapor-solid mechanism of ZnO nanowires nucleation and growth on amorphous diamond was established. (C) 2005 Elsevier B.V. All rights reserved.