From Preannealing of Bilayer Catalysts To Explore the Growth Micromechanisms of ZnO Nanorods

• Published in: Crystal growth & design 2010-02, Vol.10 (2), p.977-982
• Main Authors: Kuo, Dong-Hau, Chang, Bo-Jie
• Format: Article
• Language: English
• Subjects: Chemical synthesis methods; Chemistry; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; General and physical chemistry; General, apparatus; Materials science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Nanoscale materials and structures: fabrication and characterization; Physics; Quantum wires; Surface physical chemistry; Theory and models of crystal growth; physics of crystal growth, crystal morphology and orientation
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg901285f

The growth of ZnO nanorods was investigated by having the catalysts in bilayer configurations of Au (top)/Al (bottom), Au/Ni, and Au/In. These catalyst layers were preannealed at 700 or 850 °C in an argon atmosphere. The different growth behaviors were investigated for the complex bilayer catalyst systems in order to indirectly explore the growth micromechanism from an atomistic viewpoint. Experimental results demonstrated that the higher preannealing temperature led to smaller rods. The 850 °C preannealed Au/Al catalyst system performed the growth of hexagonal-shaped ZnO nanorods with a size of 100 nm in cross section. Preannealing is thought to modify the surface energy of catalyst templates through the alloying treatments, which is followed by the growth of ZnO nanorods via a vapor−solid growth mechanism. Growth modes are rationalized by considering the state of catalyst in quasi-liquid or crystal and the type of absorbed species in Zn metal or ZnO molecule.