ZnO nanocrystals from dot to rod were synthesized by simply changing Zn2+ concentration in ZnO seed solutions. The growth of ZnO nanocrystals was sensitive to the amount of Zn2+ in the solution. The growth process of ZnO from dot to rod was observed by optical spectra, C transmission electron microscopy and X-ray diffraction spectra. From these results, the growth mechanism of ZnO from dots to rods was discussed. (c) 2005 Elsevier Inc. All rights reserved.