In this Letter, the Raman scattering and room-temperature photoluminescence (PL) spectra of the ZnO nanoplatelets and rectangular cross-sectioned nanowires have been investigated. Different Raman scattering modes were observed by using Ar+ 514.5 nm and He-Cd 325 nm beams as excitation sources. Compared with the Raman spectra of the nanowires, red shift and asymmetry broadening of the resonance peaks were observed for ZnO nanoplatelets, which are attributed to the phonon confinement and size effect for low dimensional materials. Room-temperature PL spectra studies indicated that oxygen deficiency and surface dislocation were important factors influencing the PL behavior of the ZnO nanocrystals. (c) 2006 Elsevier B.V. All rights reserved.