SOME EVIDENCE FOR THE OCTA-TWIN MODEL OF TETRAPOD ZNO PARTICLES

Transmission electron microscopy at the central part of tetrapod-shaped ZnO particles, produced by oxidizing zinc vapor in air, has revealed that there exist trigonal-pyramid crystals other than the leg crystals at the center. Scanning electron microscopy of fractured tetrapod particles has shown characteristic facetted fracture surfaces. These results, together with the etch patterns on the surfaces of the particles which exhibit polarities of the constituent crystals, are consistent with the previously proposed growth model from an inversion-type octa-twin embryo.