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ZnS Nanowires (zn + nanowire)

Distribution by Scientific Domains

Polymers and Materials Science	83%

Selected Abstracts

Preparation, structure and photoluminescence properties of SiO2,coated ZnS nanowires

CRYSTAL RESEARCH AND TECHNOLOGY, Issue 10 2010
Changhyun Jin
Abstract It is essential to passivate one-dimensional (1D) nanostructures with insulating materials to avoid crosstalking as well as to protect them from contamination and oxidation. The structure and influence of thermal annealing on the photoluminescence properties of ZnS-core/SiO2 -shell nanowires synthesized by the thermal evaporation of ZnS powders followed by the sputter deposition of SiO2 were investigated. Transmission electron microscopy and X-ray diffraction analyses revealed that the cores and shells of the core-shell nanowires were single crystal zinc blende-type ZnO and amorphous SiO2, respectively. Photoluminescence (PL) measurement showed that the core-shell nanowires had a green emission band centered at around 525 nm with a shoulder at around 385 nm. The PL emission of the core-shell nanowires was enhanced in intensity by annealing in an oxidative atmosphere and further enhanced by subsequently annealing in a reducing atmosphere. Also the origin of the enhancement of the green emission by annealing is discussed based on the energy-dispersive X-ray spectroscopy analysis results. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Synthesis and Optical Properties of Europium-Doped ZnS: Long-Lasting Phosphorescence from Aligned Nanowires,

ADVANCED FUNCTIONAL MATERIALS, Issue 11 2005
C. Cheng
Abstract Quasi-aligned Eu2+ -doped wurtzite ZnS nanowires on Au-coated Si wafers have been successfully synthesized by a vapor deposition method under a weakly reducing atmosphere. Compared with the undoped counterpart, incorporation of the dopant gives a modulated composition and crystal structure, which leads to a preferred growth of the nanowires along the [010] direction and a high density of defects in the nanowire hosts. The ion doping causes intense fluorescence and persistent phosphorescence in ZnS nanowires. The dopant Eu2+ ions form an isoelectronic acceptor level and yield a high density of bound excitons, which contribute to the appearance of the radiative recombination emission of the bound excitons and resonant Raman scattering at higher pumping intensity. Co-dopant Cl, ions can serve not only as donors, producing a donor,acceptor pair transition with the Eu2+ acceptor level, but can also form trap levels together with other defects, capture the photoionization electrons of Eu2+, and yield long-lasting (about 4,min), green phosphorescence. With decreasing synthesis time, the existence of more surface states in the nanowires forms a higher density of trap centers and changes the crystal-field strength around Eu2+. As a result, not only have an enhanced Eu2+ 4f65d1,4f7 intra-ion transition and a prolonged afterglow time been more effectively observed (by decreasing the nanowires' diameters), but also the Eu2+ related emissions are shifted to shorter wavelengths. [source]

One-Step Preparation of Coaxial CdS,ZnS and Cd1,xZnxS,ZnS Nanowires,

ADVANCED FUNCTIONAL MATERIALS, Issue 8 2005
Y.-J. Hsu
Abstract Preparation of coaxial (core,shell) CdS,ZnS and Cd1,xZnxS,ZnS nanowires has been achieved via a one-step metal,organic chemical vapor deposition (MOCVD) process with co-fed single-source precursors of CdS and ZnS. Single-source precursors of CdS and ZnS of sufficient reactivity difference were prepared and paired up to form coaxial nanostructures in a one-step process. The sequential growth of ZnS on CdS nanowires was also conducted to demonstrate the necessity and advantages of the precursor co-feeding practice for the formation of well-defined coaxial nanostructures. The coaxial nanostructure was characterized and confirmed by high-resolution transmission electron microscopy and corresponding energy dispersive X-ray spectrometry analyses. The photoluminescence efficiencies of the resulting coaxial CdS,ZnS and Cd1,xZnxS,ZnS nanowires were significantly enhanced compared to those of the plain CdS and plain Cd1,xZnxS nanowires, respectively, owing to the effective passivation of the surface electronic states of the core materials by the ZnS shell. [source]

Oriented Assemblies of ZnS One-Dimensional Nanostructures ,

ADVANCED MATERIALS, Issue 9-10 2004
Y.-C. Zhu
Oriented ZnS nanobelt arrays and ZnS multicore microcables consisting of oriented nanowire bundles with sheaths (see Figure) have been synthesized via a controlled thermal process. Both the ZnS nanowires and nanobelts are single crystals grown along the [001] axis. The special structures of the oriented assemblies of ZnS one-dimensional nanostructures may have potential applications in nanoelectronics and photonics. [source]

ZnS Nanowires with Wurtzite Polytype Modulated Structure,

ADVANCED MATERIALS, Issue 14 2003
Y. Jiang
A novel polytype modulated 1D structure has been grown in ZnS nanowires via intermittent laser ablation,catalytic growth. The polytype modulated ZnS nanowires show a strong blue-shifted bandgap emission centered at 338.2 nm due to quantum size effects. The Figure shows a dark-field image of one of the nanowires (top) and the corresponding electron diffraction patterns (bottom). [source]