Growth of Ternary Oxide Nanowires by Gold-Catalyzed Vapor-Phase Evaporation

Zn 2 SnO 4 nanowires and Zn 2 SnO 4 diameter-modulated (DM) nanowires were successfully synthesized, accompanied by the formation of ZnO nanowires, via the thermal evaporation of a mixture of ZnO and SnO 2 powders, using gold as a catalyst. Their morphologies and structures were characterized by scanning electron microscopy, X-ray spectroscopy, and high-resolution transmission electron microscopy. The ZnO nanowires were single crystalline, with an axis of [011̄0], which is different from the conventional [0001] orientation and might be determined by the vapor components involved in the reaction. Zn 2 SnO 4 nanowires and Zn 2 SnO 4 DM nanowires were single crystalline, with [302] and [111] growth directions, respectively. A vapor−liquid−solid (VLS) growth mechanism is proposed, to interpret the growth of nanowires in the experiment. In regard to the formation of Zn 2 SnO 4 DM nanowires, we suggest that the disturbance of vapor concentration is a major factor that changes the size of the catalyst alloy droplets and the growth velocity of nanowires, and ultimately results in the diameter-modulated feature.