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We compare the field emission characteristics of dense (10 9 nanofibers/cm 2), sparse (10 7 nanofibers/cm 2), and patterned arrays (10 6 nanofibers/cm 2) of vertically aligned carbon nanofibers on silicon substrates. The carbon nanofibers were prepared using plasma-enhanced chemical vapor deposition of acetylene and ammonia gases in the presence of a nickel(More)
A comparative study of the low temperature conductivity of an ensemble of multiwall carbon nanotubes and semiconductor nanowires is presented. The quasi one‐dimensional samples are made in nanoporous templates by electrodeposition and CVD growth. Three different structures are studied in parallel: multiwall carbon nanotubes, tellurium nanowires, and silicon(More)
Porous alumina templates have been fabricated by applying an exponential voltage decrease at the end of the anodization process. The time constant η of the exponential voltage function has been used to control the average thickness and the thickness distribution of the barrier layer at the bottom of the pores of the alumina structure. Depending on the η(More)
Multi-walled carbon nanotubes (MWCNTs) have been grown on 7 nm Ni-coated substrates consisting of crystalline silicon covered with a thin layer (10 nm) of TiN, by combining hot-wire chemical vapor deposition (HWCVD) and direct current plasma-enhanced chemical vapor deposition (dc PECVD), at 620-C. Acetylene (C 2 H 2) gas is used as the carbon source and(More)
Multi-walled carbon nanotubes have been grown on 7 nm Ni-coated substrates consisting of 300 lm thick highly n-doped (1 0 0) silicon covered with a diơusion barrier layer (10 nm thick) of SiO 2 or TiN, by combining hot-wire chemical vapor deposition and direct current plasma-enhanced chemical vapor deposition at low temperature (around 620 °C). Acetylene(More)
Carbon nanotubes and semiconductor nanowires have been thoroughly studied for the future replacement of silicon-based complementary metal oxide semiconductor (CMOS) devices and circuits. However, the organisation of these nanomaterials in dense transistor arrays, where each device is capable of delivering drive currents comparable with those of their(More)
The increasingly demand on secondary batteries with higher specific energy densities requires the replacement of the actual electrode materials. With a very high theoretical capacity (4200 mAh g ­1) at low voltage, silicon is presented as a very interesting potential candidate as negative electrode for lithium-ion micro-batteries. For the first time, the(More)
71 hydrogen plasma treatment 3.6 SUMMARY Room temperature exposure to a RF hydrogen plasma can dramatically reduce the thermal budget for the crystallization of PECVD a-Si:H films. The hydrogen plasma treatment changes the microstructure of the q-Si:Hat the surface, and depletes hydrogen from the surface of the film. The plasma treatment creates seed nuclei(More)
Confined lateral alumina templates are fabricated with different pore sizes by changing the acid electrolyte and the anodization voltage. The control of the number of pore rows down to one dimension is also achieved, by controlling the thickness of the starting aluminum film as well as the anodization voltage. We observe that the mechanism of pore formation(More)