Characterization of ion/electron beam induced deposition of electrical contacts at the sub-{\mu}m scale

We investigate the fabrication of electrical contacts using ion- and electron-beam induced deposition of platinum at the sub-\mu m scale. Halos associated with the metal surface decoration are characterized electrically in the 0.05-2 \mu m range using transport measurements, conducting atomic force microscopy and Kelvin probe microscopy. In contrast with IBID, EBID electrodes exhibit weakly conductive halos at the sub-\mu m scale, and can thus be used to achieve resist-free electrical contacts for transport measurements at the sub-\mu m scale. Four-point transport measurements using \mu m-spaced EBID contacts are provided in the case of a multiwalled carbon nanotube

Complex conductivity of YBCO films in normal and superconducting states probed by microwave measurements

We report on microwave frequency characterization of yttrium barium copper oxide (YBCO) thin films in both normal and in superconducting state. A microwave single-post dielectric resonator technique using two different resonators was used for the complex conductivity determination of YBCO samples on dielectric substrates. The intrinsic complex conductivity of YBCO films was determined from the measured resonator quality factor Q and resonant frequency values employing rigorous electromagnetic modelling of the resonant structures with the mode-matching and Rayleigh-Ritz techniques. Such approach allowed us to determine the intrinsic properties of the films (conductivity, permittivity, and penetration depth) without any simplifications or errors associated with appropriate modelling employing perturbation theory. We describe the superconducting material only through its intrinsic properties, such as complex conductivity, which does not depend on the thickness of the sample and other parameters. Fro both simulations and experimental results we show that the proposed method of intrinsic complex conductivity determination is particularly useful for the characterisation of very thin YBCO films. To support the novelty of our approach it is shown that significant differences appear between the rigorous and perturbation computations for thin films (below 50nm)

Studies of Multiwall Carbon Nanotubes Using Raman Spectroscopy and Atomic Force Microscopy

score: 0collation: 265-26

Charging and emission effects of multiwalled carbon nanotubes probed by electric force microscopy

Electrostatic properties of single-separated multiwalled carbon nanotubes (MWCNTs) deposited on a dielectric layer have been investigated by charge injection and electric force microscopy (EFM) experiments. We found that upon local injection from the biased EFM tip, charges delocalize over the whole nanotube length (i.e., 1-10 μ m), consistent with a capacitive charging of the MWCNT-substrate capacitance. In addition, the insulating layer supporting the nanotubes is shown to act as a charge-sensitive plate for electrons emitted from the MWCNTs at low electric fields, thus allowing the spatial mapping of MWCNT field-emission patterns. © 2005 American Institute of Physics

Fundamental studies in nanosciences at the Institute of Electronics, Microelectronics, and Nanotechnology (IEMN)

This paper gives an overview over the fundamental research in nanosciences at the Institute of Electronics, Microelectronics and Nanotechnology (IEMN). We present some highlights from the numerical simulation of the electronic structure of nanowires and nanotubes, the charge spectroscopy of Si nanoparticles and C nanotubes, the scanning tunnelling spectroscopy of semiconductor quantum dots, to research in surface science for bio-screening