Morphology nanowire

Among the variety of morphologies, nanowires are emerging as a powerful class of materials that, through controlled growth and organization, are opening up substantial opportunities for novel nanoscale photonic and electronic devices [352]. 

We found recently that the viscosity (//vac) of the colloidal thiolate precursor is a key parameter in controlling the shape of the nanoproducts in the solventless method [8]. Uniform nanowires, rods, or spheres could be made from the corresponding precursors that came from the solutions with different viscosities. The viscosity is a measure of the polymerization of the metal-thiolate complexes. Accordingly, the precursor with the highest viscosity produces nanowires (Fig. 20.5 a), and with decreases in the viscosity, the product morphology changes to rods (Fig. 20.5b) and then spheres (Fig. 20.5c). 

Of the various semiconductors tested to date, Ti02 is the most promising photocatalyst because of its appropriate electronic band structure, photostability, chemical inertness and commercial availability. But currently, a variety of nanostmctured Ti02 with different morphologies including nanorods, nanowires, nanostmctured films or coatings, nanotubes, and mesoporous/nanoporous structures have attracted much attention. 

In general, the various synthesis strategies for nanocarbon hybrids can be categorized as ex situ and in situ techniques [3]. The ex situ ( building block ) approach involves the separate synthesis of the two components prior to their hybridization. One can rely on a plethora of scientific work to ensure good control of the component s dimensions (i.e. size, number of layers), morphology (i.e. spherical nanoparticles, nanowires) and functionalization. The components are then hybridized through covalent, noncovalent or electrostatic interactions. In contrast, the in situ approach is a one-step process that involves the synthesis of one of the components in the pres-... 

Morphology of Si-Based Nanowires. The overall diameters of SiNW produced so far range from 3 nm to 100 nm, and many methods have yielded a frequently occurring diameter of 15 nm when they are made between the temperature of 1100 and 1200°C. This size of nanowires, as speculated at the end of this chapter, may be determined by the selected growth temperature. 

Other morphologies have also been made and observed for SiNW. Although straight nanowires dominate, other forms such as string beans (strings of pearls), shells. 

Improved morphology and compositions of SiNW can further enable many new applications. For example, SiO c nanowires usually possess the most intense blue PL 47,48 ]-ecent study, long wavelength PL from oxygen vacancies in Si02 has... 

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