Synthesis and photoluminescence properties of SnO2/ZnO hierarchical nanostructures

SnO2/ZnO hierarchical nanostructures were synthesized by a two-step carbon assisted thermal evaporation method. SnO2 nanowires were synthesized in the first step and were then used as substrates for the following growth of ZnO nanowires in the second step. Sn metal droplets were formed at the surfaces of the SnO2 nanowires during the second step and were acted as catalyst to facilitate the growth of ZnO nanowires via vapor–liquid–solid mechanism. Room temperature photoluminescence measurements showed that the SnO2/ZnO hierarchical nanostructures exhibited a strong green emission centered at about 520 nm and a weak emission centered at about 380 nm. The emissions from the SnO2 were drastically constrained due to screen effect caused by the ZnO layer.