ZnO particles were synthesized directly from an aqueous solution of zinc acetate dihydrate in the presence of sodium dodecyl sulfate (SDS) and sodium hydroxide at 70 degrees C. The morphological changes were investigated in the range of pH 8-12. The hexagonal prism-like shape was formed at pH 8 and 10 by inhibition of growth along the c direction whereas the small rod-like shape was observed at pH 12. The estimated band gap and the room temperature photoluminescence intensity in a visible region are dependent upon the geometrical shape and size of the ZnO particles. (C) 2010 Elsevier B.V. All rights reserved.