Hydrothermal-Electrochemical Synthesis of ZnO Nanorods

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 oil Si substrates which were coated with a platinum conducting layer and a ZnO seed layer. They possessed a single-crystal wurizite structure and grew along the c-axis, perpendicular to the substrates. The height and diameter of the ZnO nanorods were tip to similar to 4.3 mu m 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 degrees C) and the presence of NaOH additive. The nanorods synthesized at high temperature (180 degrees C) exhibited a strong UV emission and a weak defect-related visible emission leading to a UV-visible ratio of similar to 230. This high optical quality was attributed to the increased growth rate of ZnO nanorods (similar to 4.3 mu m/h) which was caused by the high growth temperature (180 degrees C). This was based oil 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 sythetic method may provide a promising way for fabricating high performance optoelectronic devices oil flexible polymer substrates.