Hydrothermal−Electrochemical Synthesis of ZnO Nanorods

• Published in: Crystal growth & design Vol. 9; no. 8; pp. 3615 - 3620
• Main Authors: Park, Seong Kyong, Park, Jae Hyoung, Ko, Ki Young, Yoon, Sungho, Chu, Kyo Seon, Kim, Woong, Do, Young Rag
• Format: Journal Article
• Language: English
• Published: Washington,DC American Chemical Society 05.08.2009
• Subjects: Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Growth from solutions; Materials science; Methods of crystal growth; physics of crystal growth; Methods of nanofabrication; Nanoscale materials and structures: fabrication and characterization; Other topics in nanoscale materials and structures; Physics; Quantum wires; Growth rate; Electrochemical method; Photoluminescence; Optoelectronic devices; Crystal seeds; Monocrystals; Hydrothermal synthesis; Zinc hydroxide; Aqueous solutions; Platinum; Growth mechanism; Wurtzite structure; Crystal growth from solutions; Zinc oxide; Polymers; Nanorod; Nanostructured materials; Nanomaterial synthesis; Crystal structure
• ISSN: 1528-7483; 1528-7505
• DOI: 10.1021/cg9003593

Vertically aligned ZnO nanorods having high optical quality were prepared by a hydrothermal−electrochemical method. The nanorods were synthesized in a Zn(NO3)2 aqueous solution on Si substrates which were coated with a platinum conducting layer and a ZnO seed layer. They possessed a single-crystal würtzite structure and grew along the c-axis, perpendicular to the substrates. The height and diameter of the ZnO nanorods were up to ∼4.3 μm and 90−150 nm, respectively. The morphological, structural, and photoluminescence properties of the ZnO nanorods were examined with respect to the growth temperature (120−180 °C) and the presence of NaOH additive. The nanorods synthesized at high temperature (180 °C) exhibited a strong UV emission and a weak defect-related visible emission leading to a UV−visible ratio of ∼230. This high optical quality was attributed to the increased growth rate of ZnO nanorods (∼4.3 μm/h) which was caused by the high growth temperature (180 °C). This was based on the fact that the ZnO phase is thermodynamically more favorable than the defect-related Zn(OH)2 phase at higher temperature. Since the growth temperature was compatible with polymer materials, our synthetic method may provide a promising way for fabricating high performance optoelectronic devices on flexible polymer substrates.