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We present a detailed study on the growth process of cupric oxide (CuO) nanowires by thermal oxidation. The morphology of nanowires, obtained at different oxidation temperatures and times, was determined. The diameter of nanowires was found to depend linear on temperature whereas the time dependence of their length is modeled by a parabolic law. The results suggest that CuO nanowires are formed as a result of the competition between grain boundary and lattice diffusion of Cu atoms across a Cu2O layer. Electrical characterization of the nanowires was also performed. A field effect transistor was produced with an isolated nanowire showing p-type characteristics. The resistivity, mobility, and density of carriers were calculated. Nanowire growth by thermal oxidation is very simple and has great potential to be used for large scale production; this opens possibilities for various kinds of application. [ABSTRACT FROM AUTHOR]

We present a detailed study of the growth of multiwall and single-wall carbon nanotubes (SWCNTs) by chemical-vapor deposition using a thin-film triple metal (Al/Fe/Mo) catalyst. Using Nanoauger spectroscopy, a full map of the metals in the sample surface is constructed and their evolution followed at different deposition temperatures. During the formation of SWCNTs at high temperatures (∼1000 °C), the initial iron layer (∼1 nm) is transformed into nanosized particles at the surface. In addition, the Al layer also plays a critical role during the annealing process by being altered into AlxOy particles. These particles act as a suitable underlayer to stabilize the nanosized Fe catalyst for nanotube growth. We also show that it is possible to resolve SWCNTs by mapping the areal intensity of carbon KVV Auger electrons. [ABSTRACT FROM AUTHOR]

Hydrogenated carbon-nitride films (CN[sub x]:H) were deposited by evaporation of aza-adenine (8-aza-6-aminopurine, C[sub 4]N[sub 6]H[sub 4]) and irradiated during film growth by a nitrogen ion beam with energies of 25, 50, and 100 eV. The relationship between the deposition conditions and the chemical bonding structure was investigated by x-ray photoelectron and infrared spectroscopies. The mass density of the films was estimated from the C 1s plasmon energy and the optical properties were examined by ultraviolet-visible spectroscopy. The infrared spectra indicate that in the case of evaporated films, the molecular structure of aza-adenine is preserved without substantial nitrogen loss (N/Capprox. 1.3). With increasing energy of the assisting nitrogen ion beam, the structure is subsequently transformed into an amorphous phase. This transition is accompanied by an increasing nitrogen loss down to N/Capprox. 0.8, a decrease of the optical band gap, and an increase of the film density. The known molecular structure of aza-adenine permits the reconstruction of the C 1s and N 1s core-level spectra with deconvoluted spectral components representing the different bonding environments of C and N atoms present in the molecule. The spectral components are identified by comparing the experimental data with theoretical calculations of the corresponding binding energies. By analysis of the spectral changes induced by the nitrogen ion beam with increasing energies, it is possible to study the microstructural modifications of the material. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated the coefficient of thermal expansion and biaxial modulus of some amorphous semiconductors and metallic thin films. Experimental procedure; Results and discussion; Conclusions.