Well-aligned Zn1-xMgxO nanorods (x = 0-0.165) have been grown on Si(0 0 1) substrates using metalorganic chemical vapor deposition. Structural analyses indicate that the nanorods grown on Si substrates are oriented in the c-axis direction and the nanorod possesses the single-crystal line hexagonal structure. No phase separation is observed when the Mg content (x) is increased to 0.165. The c-axis constant of the Zn-1-xMgxO nanorod decreases with increasing Mg content. The PL emission energies of the Zn1-xMgxO nanorods measured at room temperature increase monotonically with the Mg contents. (C) 2005 Elsevier B.V. All rights reserved.