6 research outputs found
Electrical transport properties of small diameter single-walled carbon nanotubes aligned on ST-cut quartz substrates
A method is introduced to isolate and measure the electrical transport
properties of individual single-walled carbon nanotubes (SWNTs) aligned on an
ST-cut quartz, from room temperature down to 2 K. The diameter and chirality of
the measured SWNTs are accurately defined from Raman spectroscopy and atomic
force microscopy (AFM). A significant up-shift in the G-band of the resonance
Raman spectra of the SWNTs is observed, which increases with increasing SWNTs
diameter, and indicates a strong interaction with the quartz substrate. A
semiconducting SWNT, with diameter 0.84 nm, shows Tomonaga-Luttinger liquid and
Coulomb blockade behaviors at low temperatures. Another semiconducting SWNT,
with a thinner diameter of 0.68 nm, exhibits a transition from the
semiconducting state to an insulating state at low temperatures. These results
elucidate some of the electrical properties of SWNTs in this unique
configuration and help pave the way towards prospective device applications
Embedding a Carbon Nanotube across the Diameter of a Solid State Nanopore
A fabrication method for positioning and embedding a single-walled carbon nanotube (SWNT) across the diameter of a solid state nanopore is presented. Chemical vapor deposition (CVD) is used to grow SWNTs over arrays of focused ion beam (FIB) milled pores in a thin silicon nitride membrane. This typically yields at least one pore whose diameter is centrally crossed by a SWNT. The final diameter of the FIB pore is adjusted to create a nanopore of any desired diameter by atomic layer deposition, simultaneously embedding and insulating the SWNT everywhere but in the region that crosses the diameter of the final nanopore, where it remains pristine and bare. This nanotube-articulated nanopore is an important step towards the realization of a new type of detector for biomolecule sensing and electronic characterization, including DNA sequencing.Engineering and Applied SciencesMolecular and Cellular BiologyPhysic
Direct Patterning of Boron-doped Amorphous Carbon Using Focused Ion Beam-assisted Chemical Vapor Deposition
The deposition of boron-doped amorphous carbon thin films on SiO2 substrate
was achieved via a focused ion beam-assisted chemical vapor deposition of
triphenyl borane (C18H15B) and triphenyl borate (C18H15BO3). The existence of
boron in the deposited film from triphenyl borane, with a precursor temperature
of 90 {\deg}C, was confirmed by a core level X-ray photoelectron spectroscopy
analysis. The film exhibited a semiconducting behavior with a band gap of 285
meV. Although the band gap was decreased to 197 meV after an annealing process,
the film was still semiconductor. Additionally, a drastic reduction of the
resistance on the deposited film by applying pressures was observed from an
in-situ electrical transport measurements using a diamond anvil cell