Growth mechanism and characterization of rose-like microspheres and hexagonal microdisks of ZnO grown by surfactant-free solution method

Highly crystalline rose-like microspheres made of nanosheets and hexagonal microdisks of zinc oxide (ZnO) were grown on Si and ZnO/Si substrates, respectively in solution at 90 degrees C without the use of any surfactants. The microdisks had lower defects and better optical properties than the microspheres and showed a strong UV emission at 378 nm. A possible growth mechanism based on the electrostatic forces between polarized ZnO nanostructures and substrates and the surface energy was proposed for the growth of microspheres and microdisks. (C) 2008 Published by Elsevier B.V. on behalf of The Korean Society of Industrial and Engineering Chemistry.