Preparation and optical properties of one dimensional nano hydroxides and oxides

Abstract

The Yttrium hydroxide nanotubes and nanorods as well as the ZnO nanorods and nanowires were prepared by different methods. Y(OH)3 nanotubes and nanorods were synthesized by polyol – mediation via the metastable precursor YCl3, PEG and were studied by FE SEM and XRD. The influence of the polymer molecular weights of PEG and the temperature were studied in detail. These results show that the first stage is nanorods, then it is followed by the formation of nanotubes. The outer diameter of the tubes is about 150 nm to 600 nm and interior hollow is in the range between 100 nm to 300 nm. The length of the rods and the tubes is up to several micrometers. We have found that the synthesis temperature, reaction rate and molecular weight of PEG induce the change in shape of obtained nanotubes from a cylindrical to a hexagonal appearance. The growth process of the nanotubes may be performed through three stages: first complexing the PEG polymer with Y(NO3)3, then hydrolysis for formating Y(OH)3 nanorods and finally diffusion-controlled developing of Y(OH)3 nanotubes. The ZnO nanorods were prepared by Chemical Vapor Deposition (CVD) and Metal Organic Chemical Vapor Deposition (MOCVD) method, respectively. Aligned growth of ZnO nanorods has been successfully prepared. The nanorods have the diameters of about 50 nm and the length of about 1.12 micrometers. The influence of the temperature is investigated. The luminescent spectra (excited by Cd-He laser at 325 nm) of ZnO nanorods at 10 K- 300 K was measured and investigated. The sharp peak is assigned to an exciton bound to a neutral donor.