A two-step route to self-assembly of CdS nanotubes via electrodeposition and dissolution

Polycrystalline CdS nanotubes (CNTS) were successfully achieved by a two-step treatment, i.e. (CdS+Cd) nanowires (electrodeposition and sulfuration process in anodic alumina membrane) --> CNTs (dissolution method of removing Cd in 0,5 m HCl). Having been characterized using X-ray diffraction and scanning electron microscopy, the nanowires, the intermediate products, contain Cd and CdS, and have uniform diameters of about 80 nm and lengths of up to 25 mum, which correspond to the pore size and thickness of the membrane used. The average inner and outer diameters of the as-obtained CNTs are respectively 40 and 80 nm via trans-mission electron microscopy. Selected area electronic diffraction, X-ray diffraction and X-ray photoelectron energy spectroscopy investigations demonstrate that these CNTs with hexagonal wurtzite polycrystalline structure are pure and stoichiometric. The successful synthesis of these semiconductor CNTs may open up new possibilities for studies of fundamental properties and potential applications of semiconductor nanotubes. ((C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003).