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We describe a facile and one-step pulsed laser deposition (PLD) technique that was utilized for the first time to systematically fabricate a series of innovative Bi2Te3 superassembly-on-epitaxy bi-layer nanostructures, by uniquely coupling the upper self-assembled well-ordered Bi2Te3 hierarchical nanostructures with unusually high surface- and interface-to-volume ratios and a highly electrical conductive epitaxial bottom thin layer on insulated SiO2/Si substrates, as an emerging new class of the most advanced thermoelectric nanomaterials. The optimized power factor of the present superassembly-on-epitaxy films is one to three orders of magnitude higher than that of most Bi2Te3 nanoassemblies defined as the assemblies of nanocrystals, evidently proving the significance and potential of the present new concept and the resulting thermoelectric nanomaterials. [ABSTRACT FROM AUTHOR]

Influence of post-treatment processes on the morphology of Fe-catalyst and the characteristics of the subsequently grown carbon nanotubes were systematically investigated. The reducing agent, which is either H2 gases species or cracked ammonia, NH3, imposed most marked effect on the morphology of Fe-clusters. The Fe-catalysts, which were prepared from 0.1 M Fe(OR)3 in xylene and were reduced by NH3 gas species, are nano-sized (50 nm), isolated and uniformly distributed. They result in carbon nanotubes of the highest purity and most density populated, exhibiting the largest electron field emission capacity. The Fe catalysts prepared by other conditions are interconnected or coarsened particulates, which induces the formation of carbon soots. The electron field emission capacity of the CNTs films is thus markedly decreased. These results imply that spin coating of Fe(OR)3 is a simple and inexpensive method for preparing catalyst of good quality, which can produce high purity carbon nanotubes, provided that the processing parameters are well controlled. A simple and inexpensive method for preparing Fe-catalyst of good quality, spin coating of Fe(OR)3 technique, was developed. This technique has the potential for scaling up and for selectively growing CNTs for electron emitters’ application. [Copyright &y& Elsevier]

We describe an innovative interfacial design concept and nanostructuring of novel Bi x Sb 2-x Te 3 (BST) nanoassembled films comprising unique air-solid interfaces from micro-scaled open gaps to isolated sealed mesopores, and high-quality solid-solid ones including the coherent grain boundaries and specific twins, utilizing pulsed laser deposition (PLD), for potentially activating multiple thermoelectric enhancing mechanisms. The unusual mesopore embedded BST films exhibit the highest power factor of ∼33 μW cm -1 K -2 , which is comparable to or higher than the previously reported values for BST, and the corresponding relatively low thermal diffusivity in contrast to that for dense pore-less BST films evidently reveals the crucial role of the three-dimensionally and densely arranged air-solid interfaces in significantly arising the phonon scattering.