Catalyst-free synthesis and luminescence of aligned ZnO nanorods

Quasi-aligned undoped ZnO nanorods with diameter in the range 100-300nm and length of several micrometers have been grown catalyst-free on Si(1 0 0) wafer in a one-step process by direct heating of Zn powders. All nanowires are single crystals and are aligned vertically to the substrate surface with c-axis preferred orientation. XRD, HRTEM and Raman studies revealed that the ZnO nanorods have wurtzite phase, are highly crystalline and well aligned with the lattice parameters a = 0.32 nm, and c = 0. 52 nm. The PL spectra measured at different temperatures are dominated by excitonic emission at similar to 380 nm and less intense below band gap emission band centered at 520 nm. (c) 2007 Elsevier B.V. All rights reserved.