%0 Journal Article
%T Liquid Phase Morphology Control of ZnO Nanowires, Ellipse Particles, Hexagonal Rods, and Particle in Aqueous Solutions
%A Yoshitake Masuda
%A Naoto Kinoshita
%A Kunihito Koumoto
%J ISRN Nanotechnology
%D 2012
%R 10.5402/2012/379510
%X Liquid phase morphology control of ZnO crystals was realized with simple aqueous solution system. ZnO nanowires were successfully fabricated at 50∼C. They were over 50ˋ米m in length and about 100ˋnm in width. Aspect ratio was estimated to be over 500. They had no branches and were obtained without aggregations. Curved nano-wires clearly indicated high flexibility and high mechanical strength. Additionally, ellipse particles, hexagonal rods and particles were fabricated in the solutions. Morphology, crystal growth speed, and preferred growth faces were well-controlled by precise adjustment of growth conditions. 1. Introduction Metal oxides have been used for electronic devices, optoelectronic device, and so forth. They will further expand beyond the present borders of research area. Especially, expectations for metal oxide nanostructures have increased recently for future applications. Syntheses of novel metal oxide nanostructures and development of their applications are under intense investigation [1每8]. Special issues [9], reviews [10每13], and books [14] on applications of metal oxide nanostructures have received a great response. ZnO has attracted much attention as varistors [15], piezoelectric devices [16], electroacoustic transducers [17], and highly transparent conducting windows for solar cells, displays [18], vacuum fluorescent displays (VFDs) [19], field emission displays (FEDs) [20], electroluminescent displays (ELDs) [21], UV light-emitting diodes (LEDs), laser diodes [22], and gas sensors [23, 24], dye-sensitized solar cells [25每29], and molecular sensors [30]. Novel ZnO nanostructures are eagerly anticipated for the applications [31每34]. ZnO nanowires especially are required for luminescent devices, dye-sensitized solar cells and high sensitive sensors. The nanowires have high electrical conductivity along the longer direction. They have large surface area due to high aspect ratio of the shape. High flexibility and high mechanical strength are required to apply for the devices. Recently, several ZnO nano-/microstructures were prepared in the solutions [34每39]. Patterning of them was realized on self-assembled monolayers (SAMs) [35]. Hydrophobic surface of SAMs accelerated deposition of ZnO nanostructures rather than hydrophilic silanol group surfaces [35]. These studies contributed development of future ZnO devices. In this study, ZnO nanowires were developed in aqueous solutions. Anisotropic crystal growth of ZnO was well-controlled by precise adjustment of solution conditions. Additionally, ellipse particles, hexagonal rods, and particles
%U http://www.hindawi.com/journals/isrn.nanotechnology/2012/379510/