170,107 research outputs found
Editorial for the special issue on carbon based electronic devices
No full textFor more than 50 years, silicon has dominated the electronics industry [...]
Relationship between sp2 carbon content and E04 optical gap in amorphous carbon-based materials
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Luminescence, recombination and laser damaging of a-CN:OH films grown by reactive sputtering
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Evaluation of [C(sp3)/[C(sp2)] ratio in diamondlike films through the use of a complex dielectric constant
No full textThe evaluation of the amount of tetrahedral and trigonal cross-linking, that is, the sp3- and sp2-hybridized carbon, is of great importance in understanding the properties of amorphous carbon films. In this paper we report a method for deducing the [sp3]/[sp2] ratio from the experimental values of the complex dielectric constant as obtained by optical transmittance and reflectance measurements. We assume a Gaussian-like distribution of π and π* electronic densities of states in order to fit the contribution of π→π* to the imaginary part, ε2, of the dielectric constant in the low-energy region. Through the Kramers-Kronig relationships we deduce the corresponding values of the real part ε1 of the dielectric constant for such transitions. By subtracting these values from the measured ε1 we deduce the contribution of σ→σ* to ε1. The Wemple-Didomenico model has been used to obtain the dispersion energy and the average excitation energy. Knowing the plasmon energies, we apply the ‘‘f-sum rule'' to deduce the [sp3]/[sp2] ratio. The method applied to a-C:H films deposited by rf diode sputtering provides results in agreement with those obtained by other techniques
Hall effect studies and magnetic behaviour in Fe-nanoparticle embedded multi wall CNTs
No full textWith reference of our previous report [JNN 9, (2009) 6799], here we extended our work on ironnanoparticles embedded multiwall carbon nanotubes (MWCNTs) that were grown at 850 °C using chemical vapour deposition process that shows ferromagnetic as well as magnetic anisotropic behaviour due to the non-uniform distribution of 'Fe' particles in CNTs. The separation of 'Fe' nanoparticles from each other by the nonmagnetic carbon nanotube walls is preferably suitable for the application of magnetic storage devices, magnetic recording media and electromagnetic devices. The spin-related phenomenon in MWCNTs is demonstrated through a temperature dependent resistance curve through metal-insulator transition at ∼12.6 K and field effect magneto-resistance (MR). The minimal resistance is observed at 12.6 K. This result could provide the fabrication of nanometric-scale electronic devices and opening new opportunities to uncover deeper aspects of negative magnetoresistance effect
Da Este a Padova lungo l'Adige ...
No full textIl contributo sviluppa una ipotesi topografica per la identificazione e ricostruzione della via di Lepido tra Este e Padova sulla base di nuove indagini aereofotogrammetriche condotte con nuove metodologie analitiche
Temperature dependence analysis of the electron paramagnetic resonance signal and electrical conductivity in a-C and a-C:H
No full textThe role of pi and pi* gaussian-like density of states bands in the interpretation of the physical properties of a-C and a-C:H films
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