Catalytic growth of large-scale single-crystal CdS nanowires by physical evaporation and their photoluminescence

Large-scale CdS nanowires were achieved by a new, simple, and low cost process based on thermal evaporation of US powders under controlled conditions with the presence of Au catalyst. The synthesized US nanowires have lengths up to several tens of micrometers and diameters about 60-80 nm. The growth of CdS nanowires is controlled by the conventional vapor-liquid-solid (VLS) mechanism. A strong red emission with a maximum around 750 nm was observed from the synthesized US nanowires at room temperature, which was attributed to their surface states. The technique we used is, in principle, generalizable as a means of fabricating other group II-VI semiconductor nanowires.