ZnO is a wide band gap oxide semiconductor material with important and potential applications in sensor

transducer

surface acoustic wave devices

and optoelectronic devices

etc. In the past several years

various methods have been developed for synthesizing the ZnO nanowires. Among these methods

Vapor-liquid-solid (VLS) growth mode is widely used because it does not demand complex apparatus or sophisticated techniques and one can easily synthesized the ZnO nanowires by the catalyzing process of the metal liquid drop in the tip of the nanowires. In this work

based on the VLSgrowth mechanism

we successfully prepared the twin-crystal Sn catalysted ZnO nanowires with uniform shape and wurtzite structure by a simple method of thermal evaporation of a mixture of SnO powder and Zn powder under the pure N

2

flow and O

2

flow. The pu-rity

composition

microstructrue and crystallinity of the as-prepared ZnO twin-crystal nanowires were investigated by XRD

HRTEM

SEM and SAED. According to SEM images

we observed that the as-synthesized ZnO nanowires were straight and uniform

and were 100

2

00 nm in diameter and several tens of micrometers in length

some even reaching millimeter level. TEM images and element analysis results verified that the spherical particle on the top of the nanowire was tin metal grain which played the role of catalyst in the process of nanowire growth. These suggested that the growth of ZnO twin-crystal nanowires was controlled by VLS mechanism. HRTEM images confirmed the twin-crystal structure of the nanowires. According to the SAEDimages

we made sure that the ZnO twin-crystal nanowires grew along [0110] direction and the twin-crystal plane was (1013). The relationship between the twin-crystal lattice was analyzed by the dark field images and the bright field images. We also explained the VLS growth mechanism of the nanowires.