Growth mechanism and characterization of ZnO microbelts and self-assembled

We report the structural characterization and growth mechanism of ZnO microbelts and microcombs synthesized by direct thermal evaporation and post-oxidation of the pure Zn powders. The synthesized ZnO products are hexagonal wurtzite structured and in the range of micrometer size. The formation of the microcombs follows a two-step process: the comb-stems are formed by a fast vapor-solid (VS) growth along [11 (2) over bar0] direction, and the comb-teeth are grown by a subsequent faceted epitaxial growth parallel to the (0001) polar surface. A novel structure of enantiomorphous twin-microcombs is also detected in the synthesized products. Photoluminescence (PL) spectrum shows that the prepared products are green emission, centered at about 507 nm. (C) 2005 Elsevier B.V. All rights reserved.