Keywords: ZnO, hollow spheres, MOCVD, wide-bandgap semiconductors, nanostructures, self assembly, nanotechnology, hexagonal stacking disks, metal-organic CVD, chemical vapour deposition, diethylzinc, beta hydride elimination, zinc oxide
Self assembled ZnO hollow spheres and hexagonal stacking disks by metal-organic chemical-vapour deposition
Self-assembled ZnO hollow spheres and hexagonal stacking disks were synthesised by metal-organic chemical-vapour deposition. The growth process was investigated as a function of time and the sphere and disk structures were obtained in a narrow window of a near-zero oxygen partial pressure. The largest hollow sphere has a diameter up to 20 ?m with a shell thickness of around 200 nm formed by nanocrystals or nanodisks. The hexagonal stacking disks were found to be covered with a few nanometres thick of metallic Zn observed by high-resolution transmission electron microscopy. The accumulation and dissociation of diethylzinc through beta hydride elimination process in the near-zero oxygen partial pressure was thought to be the reason for the formation of the hollow spheres and stacking disks.