رشد نانولوله‌های کربنی روی فیبرهای کربنی توسط CVD حرارتی

Growth of Carbon Nanotubes on Carbon Fiber by

Thermal CVD Using Ni Nanoparticles as Catalysts

رشد نانولوله‌های کربنی روی فیبرهای کربنی توسط CVD حرارتی

با استفاده از نانوذرات نیکل به عنوان کاتالیزور

ABSTRACT

Nickel nanoparticles and thin film on carbon fiber have been prepared through electroless deposition. Moreover, carbon nanotubes were grown on carbon fiber covered by nickel nanoparticles using thermal chemical vapor deposition. The effects of changes in the thickness of the nickel catalyst layer and the growth temperature of carbon nanotubes were studied systemically, and the results are discussed in the present work.

 

رشد ورقه های گرافن روی نانوسیم های سیلیکا با دانسیته بالا

Catalyst-free approach for growth of graphene sheets on

high-density silica nanowires byCVD

روش بدون کاتالیزور برای رشد ورقه های گرافن روی نانوسیم های سیلیکا

با دانسیته بالا توسط CVD 

ABSTRACT

A novel “two-step annealing” method is proposed for the direct synthesis of graphene sheets on high-density dielectric silica nanowires without using metal catalysts. During the first annealing at 1000 °C, the extremely thin SiO2 layer on Si substrate shrinks and forms dense nanoparticles. Using these silica nanoparticles as templates, graphene sheets and silica nanowires are synthesized simultaneously after the second annealing process at 800–850 °C. The experiment results suggest that the graphene sheets grow along the nanowires and its crystalline quality and domain size are determined by the temperature and duration of the second annealing process.

 

تولید، خواص و قابلیت‌های گرافن Production, properties and potential of graphene

Production, properties and potential of graphene

تولید، خواص و قابلیت‌های گرافن

ABSTRACT

This review on graphene, a one-atom thick, two-dimensional sheet of carbon atoms, starts with a general description of the graphene electronic structure as well as a basic experimental toolkit for identifying and handling this material. Owing to the versatility of graphene properties and projected applications, several production techniques are summarized, ranging from the mechanical exfoliation of high-quality graphene to the direct growth on carbides or metal substrates and from the chemical routes using graphene oxide to the newly developed approach at the molecular level. The most promising and appealing properties of graphene are summarized from an exponentially growing literature, with a particular attention to matching production methods to characteristics and to applications. In particular, we report on the high carrier mobility value in suspended and annealed samples for electronic devices, on the thickness-dependent optical transparency and, in the mechanical section, on the high robustness and full integration of graphene in sensing device applications. Finally, we emphasize on the high potential of graphene not only as a post-silicon materials for CMOS device application but more ambitiously as a platform for post-CMOS molecular architecture in electronic information processing.

 

سنتز نانو ورقه های ZnO از طریق روش الکترورسوبی

Synthesis of ZnO nanosheets via electrodeposition method and

their optical properties, growth mechanism

سنتز نانو ورقه های ZnO از طریق روش الکترورسوبی ، خواص نوری و مکانیزم رشد

ABSTRACT

ZnO nanosheets were prepared by electrochemical deposition method at 80 C on seeded Indium Tin Oxide conducting glass substrates. The seed layer was coated on ITO by spin coating and annealed at 350 C for 30 min prior to electrochemical deposition growth. X-ray diffraction patterns (XRD) and field emission scanning electron microscope (FESEM) images confirmed that the ZnO nanosheets consist of polycrystalline structures. Room temperature photoluminescence spectra (PL) of the ZnO nanosheets exhibited band-edge ultraviolet (UV) and visible emission (blue) indicating the ZnO nanosheets had excellent optical properties. The UV–Vis absorption spectrum of ZnO nanosheets was shown a strong absorption at 300 nm. The ZnO nanosheets structure demonstrated higher photocatalytic activity during degradation of aqueous methylene blue under visible-light irradiation. Moreover, the growth mechanism of the ZnO nanosheets had been discussed.