Electron beam induced deposition of cobalt for use as single-and multiwalled carbon nanotube growth catalyst Electron beam induced deposition of residual hydrocarbons in the presence of a multiwall carbon nanotube Appl. Phys. Lett. 95, 113112 (2009); 10.1063/1.3225553Effects of local Joule heating on the reduction of contact resistance between carbon nanotubes and metal electrodes Individual carbon nanotubes ͑CNTs͒ often occur in randomly dispersed two-dimensional as well as three-dimensional configurations that make device fabrication difficult. Making electrical contact to such CNTs is of practical interest. To this end, we make contact to individual metallic single-walled carbon nanotubes ͑SWNTs͒ using the focused electron-beam-induced deposition ͑FEBID͒ of pure gold. The SWNTs are grown by chemical vapor deposition on a flat substrate, and the gold leads are made through FEBID using inorganic metallic precursor gas, chloro͑trifluorophosphine͒gold͑I͒, or AuClPF 3 , in a high vacuum scanning electron microscope. The same scanning electron microscope is also used to image carbon nanotubes, allowing for simultaneous alignment. We find equivalent one-dimensional resistivities for the SWNTs of 10-15 k⍀ / m for both FEBID gold leads and leads deposited using conventional electron-beam lithography ͑EBL͒ and thermal evaporation of gold, suggesting similarly low contact resistances. We use electrostatic force microscopy to verify quantitatively similar contact resistances for one nanotube sample, 10 ͑±6͒ and 54 ͑±6͒ k⍀, for FEBID and EBL leads, respectively, with most voltage dropping across the long metallic SWNT.

Baida and Van Labeke recently proposed a structure that exhibits a supertransmission of light through an array of nanometric coaxial apertures in a metallic film that has been named an annular aperture array (AAA) [Opt. Commun. 209, 17 (2002); Phys. Rev. B 67, 155314 (2003); J. Microsc. 213, 140 (2003)]. We present the first experimental study, to our knowledge, of an AAA structure in the visible region. For technological reasons, the structure under study does not produce a supertransmission of 80% as in Baida and Van Labeke [Opt. Commun. 209, 17 (2002)]. We built the nanostructure and experimentally recorded its far-field spectral response. This transmission shows only one broad band with a maximum around lambda = 700 nm, giving a maximum efficiency around 17%. A finite-difference time-domain simulation reproduces quite well the obtained transmission spectrum.

Room temperature focused electron beam (FEB) induced deposition of contamination‐free transparent materials is a major issue for the FEB production of nano‐optical structures, microchip editing (insulating and passivation layers), and photolithography mask repair. In this work, stoichiometric SiO2 is successfully deposited from three different organosilanes: tetraethoxysilane (TEOS, Si(OCH2CH3)4), tetramethoxysilane (TMOS, Si(OCH3)4), and tetramethylsilane (TMS, Si(CH3)4). The FEB depositions are assisted by a molecular oxygen flux injected simultaneously with the precursor gas. The dependencies on the additional oxygen flux of the chemical compositions of the resulting deposits are studied in detail. Threshold [O2]:[precursor] molecular flux ratios, above which carbon is no longer detectable in the deposited material, are 1.75, 0.15, and 0.05, for TEOS, TMOS, and TMS, respectively. Contamination side‐reactions such as oxygen incorporation in the deposited material due to residual gases in the scanning electron microscope (SEM) chamber are shown to be significant at standard high‐vacuum operating pressures of 5 × 10–5 mbar. The quality of deposited SiO2 obtained from the three precursors is estimated by exposing the material to standard industry cleaning procedures. The etching tests indicate that TMS leads to denser deposits than the two other silanes. The optical transmissions of the deposited SiO2 obtained from TMOS and TMS are measured at 193 nm wavelength, and are 80 % and 99 %, respectively. The latter value fulfills the photomask repair requirements. Finally, hypothetical decomposition pathways of the various silanes used are discussed.

For the observation of single molecule dynamics with fluorescence fluctuation spectroscopy (FFS) very low fluorophore concentrations are necessary. For in vitro measurements, this requirement is easy to fulfill. In biology however, micromolar concentrations are often encountered and may pose a real challenge to conventional FFS methods based on confocal instrumentation. We show a higher confinement of the sampling volume in the near-field of sub-wavelength sized apertures in a thin gold film. The gold apertures have been measured and characterized with fluorescence correlation spectroscopy (FCS), indicating light confinement beyond the far-field diffraction limit. We measured a reduction of the effective sampling volume by an order of magnitude compared to confocal instrumentation.

Electron postgrowth irradiation of platinum-containing nanostructures grown by electron-beam-induced deposition from Pt ( P F 3 ) 4Investigation of morphological changes in platinum-containing nanostructures created by electron-beam-induced deposition J.Focused electron beam induced depositions of nickel-containing materials obtained by using bis͑methylcyclopentadienyl͒nickel͑II͒ Ni͑C 5 H 4 CH 3 ͒ 2 and tetrakis͑trifluorophosphine͒nickel͑0͒ Ni͑PF 3 ͒ 4 as precursors, were compared in terms of chemical composition and electrical resistivity. Ni͑PF 3 ͒ 4 decomposed into higher Ni content materials than that obtained with Ni͑C 5 H 4 CH 3 ͒ 2 ͑typically 40 and 10 at. %, respectively͒. Attempts of increasing the Ni content by injecting controlled flows of molecular oxygen or hydrogen simultaneously to the precursor vapors resulted in all cases in the increase of incorporated oxygen only. The lowest electrical resistivities of 150 nm wide lines obtained from Ni͑C 5 H 4 CH 3 ͒ 2 and Ni͑PF 3 ͒ 4 were 1 and 1 ϫ 10 −3 ⍀ cm, respectively. The electrical resistivity of the latter lines showed an e ͑−T͒ dependence with temperature, typical of magnetic heterogeneous alloys and granular alloys containing insulating particles. Transmission electron microscopy investigations of a freestanding rod obtained from Ni͑PF 3 ͒ 4 showed a nanocrystalline structure of nickel grains surrounded by a partially amorphous cladding.