Carbon Nanotube T Junctions: Formation and Properties

2008 ◽  
Vol 8 (1) ◽  
pp. 88-98 ◽  
Author(s):  
Po-Wen Chiu
Keyword(s):  
Carbon Nanotube ◽  
Photoelectron Spectroscopy ◽  
Three Dimensions ◽  
Photoelectron Spectra ◽  
Transistor Channel ◽  
X Ray ◽  
Si Substrates ◽  
Lift Off ◽  
Linker Molecules ◽  
Functionalized Nanotubes

The formation of carbon nanotube T junctions (CNTJs) and their transport properties are reviewed. The CNTJs were formed by coupling chemically functionalized nanotubes with linker molecules. Both end-to-side and end-to-end intermolecular junctions can be assembled by reacting chloride terminated nanotubes with aliphatic diamines. The functionalized nanotube mats were characterized by Raman spectroscopy and X-ray photoelectron spectroscopy. The incorporation of functional groups into nanotubes is indicated by the pronounced shift of tangential vibration modes in Raman spectra and of carbon 1s binding energy in X-ray photoelectron spectra. For transport measurements the functionalized nanotubes were adsorbed on Si substrates, and subsequent electrodes were painted on top of the selected T junctions by lithography and lift-off techniques. The bar of the "T" is used as the transistor channel and the stem of the "T" is used as the gate. In this configuration, the active area is confined to a few nanometers in all three dimensions.

Formation and Transistor Behavior of Carbon Nanotube T-junctions

2003 ◽  
Vol 772 ◽  
Author(s):  
Po-Wen Chiu ◽  
Jean-Michel Benoit ◽  
Ralf Graupner ◽  
Ursula Dettlaff ◽  
Siegmar Roth
Keyword(s):  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Electrical Transport ◽  
Three Dimensions ◽  
Vibration Modes ◽  
Metal Contacts ◽  
Transistor Channel ◽  
Si Substrates ◽  
Chemically Modified ◽  
Functionalized Nanotubes

AbstractWe present the formation of intermolecular nanotube junctions and investigations of their transistor behavior. T-shape junctions were formed by coupling chemically functionalized nanotubes with molecular linkers. An end-to-side or end-to-end heterojunction can be formed by reacting chloride terminated nanotubes with aliphatic diamine. The chemically modified nanotube mats were characterized by X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The incorporation of functional groups into nanotubes are first identified by XPS. The carbon binding energy shifts due to the doping effect by attached functional groups. This also leads to a pronounced shift of tangential vibration modes in Raman spectra. To investigate the electrical transport, functionalized nanotubes were deposited on Si substrates, and metal contacts were applied on top of the selected T-shape junctions. The bar of the “T” is used as a transistor channel and the leg of the “T” is used as a gate. In this configuration, the active area is confined to a few nanometers in all three dimensions and gain values of 100 and above are obtained.

Investigation of the Effect of Uv-Assisted Oxidation and Nitridation of Hafnium Metal Films

2003 ◽  
Vol 780 ◽  
Author(s):  
C. Essary ◽  
V. Craciun ◽  
J. M. Howard ◽  
R. K. Singh
Keyword(s):  
Uv Radiation ◽  
Photoelectron Spectroscopy ◽  
Grazing Angle ◽  
X Ray Diffraction ◽  
Metal Thin Films ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Silicon Interface

AbstractHf metal thin films were deposited on Si substrates using a pulsed laser deposition technique in vacuum and in ammonia ambients. The films were then oxidized at 400 °C in 300 Torr of O2. Half the samples were oxidized in the presence of ultraviolet (UV) radiation from a Hg lamp array. X-ray photoelectron spectroscopy, atomic force microscopy, and grazing angle X-ray diffraction were used to compare the crystallinity, roughness, and composition of the films. It has been found that UV radiation causes roughening of the films and also promotes crystallization at lower temperatures.Furthermore, increased silicon oxidation at the interface was noted with the UVirradiated samples and was shown to be in the form of a mixed layer using angle-resolved X-ray photoelectron spectroscopy. Incorporation of nitrogen into the film reduces the oxidation of the silicon interface.

scholarly journals Modification of Wood with Monoethanolamino-borate by The Data of X-Ray Photoelectron Spectroscopy

2018 ◽  
Vol 196 ◽  
pp. 04005
Author(s):  
Irina Stepina ◽  
Irina Kotlyarova
Keyword(s):  
Particle Size ◽  
Photoelectron Spectroscopy ◽  
Model Compound ◽  
Hydrolytic Stability ◽  
Photoelectron Spectra ◽  
Wood Cellulose ◽  
Rapid Loss ◽  
X Ray ◽  
Wood Protection ◽  
Cellulose Materials

The difficulty of wood protection from biocorrosion and fire is due to the fact that modifiers in use are washed out from the surface of the substrate under the influence of environmental factors. This results in a rapid loss of the protective effect and other practically important wood characteristics caused by the modification. To solve this problem is the aim of our work. Here, monoethanolaminoborate is used as a modifier, where electron-donating nitrogen atom provides a coordination number equal to four to a boron atom, which determines the hydrolytic stability of the compounds formed. Alpha-cellulose ground mechanically to a particle size of 1 mm at most was used as a model compound for the modification. X-ray photoelectron spectra were recorded on the XSAM-800 spectrometer (Kratos, UK). Prolonged extraction of the modified samples preceded the registration of the photoelectron spectra to exclude the fixation of the modifier molecules unreacted with cellulose. As a result of the experiment, boron and nitrogen atoms were found in the modified substrate, which indicated the hydrolytic stability of the bonds formed between the modifier molecules and the substrate. Therefore monoethanolaminoborate can be considered as a non-extractable modifier for wood-cellulose materials.

scholarly journals Impact of high temperatures on aluminoceladonite studied by Mössbauer, Raman, X-ray diffraction and X-ray photoelectron spectroscopy

2021 ◽  
Author(s):  
Mariola Kądziołka-Gaweł ◽  
Maria Czaja ◽  
Mateusz Dulski ◽  
Tomasz Krzykawski ◽  
Magdalena Szubka
Keyword(s):  
Photoelectron Spectroscopy ◽  
Integral Intensity ◽  
Photoelectron Spectra ◽  
X Ray Diffraction ◽  
Structural Reorganization ◽  
Oh Groups ◽  
X Ray ◽  
Al Content ◽  
Integral Intensity Ratio ◽  
Higher Temperature

AbstractMössbauer, Raman, X-ray diffraction and X-ray photoelectron spectroscopies were used to examine the effects of temperature on the structure of two aluminoceladonite samples. The process of oxidation of Fe2+ to Fe3+ ions started at about 350 °C for the sample richer in Al and at 300 °C for the sample somewhat lower Al-content. Mössbauer results show that this process may be associated with dehydroxylation or even initiate it. The first stage of dehydroxylation takes place at a temperature > 350 °C when the adjacent OH groups are replaced with a single residual oxygen atom. Up to ~500 °C, Fe ions do not migrate from cis-octahedra to trans-octahedra sites, but the coordination number of polyhedra changes from six to five. This temperature can be treated as the second stage of dehydroxylation. The temperature dependence on the integral intensity ratio between bands centered at ~590 and 705 cm−1 (I590/I705) clearly reflects the temperature at which six-coordinated polyhedra are transformed into five-coordinated polyhedra. X-ray photoelectron spectra obtained in the region of the Si2p, Al2p, Fe2p, K2p and O1s core levels, highlighted a route to identify the position of Si, Al, K and Fe cations in a structure of layered silicates with temperature. All the measurements show that the sample with a higher aluminum content and a lower iron content in octahedral sites starts to undergo a structural reorganization at a relatively higher temperature than the less aluminum-rich sample does. This suggests that iron may perform an important role in the initiation of the dehydroxylation of aluminoceladonites.

Growth of SiOx Nanowires by Simple Vapor Transport Method and their Optical Properties

2013 ◽  
Vol 534 ◽  
pp. 141-145 ◽  
Author(s):  
Yuto Hakamada ◽  
Shunji Ozaki
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Silicon Monoxide ◽  
Vapor Transport ◽  
X Ray ◽  
Si Substrates ◽  
Vls Growth ◽  
Transport Method ◽  
Vapor Transport Method ◽  
Scanning Electron

SiOx nanowires were grown on Si substrates by a simple vapor transport method of heating the mixture of silicon monoxide and carbon powders at 1000 °C in a tube of the furnace. The dependence of the growth velocity on the growth temperature and on the radius of nanowires indicates that the SiOx nanowires grow through the vaporliquidsolid (VLS) growth mechanism. The properties of the nanowires are characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and photoluminescence (PL).

scholarly journals Characterization of Ti/SnO2 Interface by X-ray Photoelectron Spectroscopy

Nanomaterials ◽  
2022 ◽  
Vol 12 (2) ◽  
pp. 202
Author(s):  
Miranda Martinez ◽  
Anil R. Chourasia
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Chemical Interaction ◽  
Photoelectron Spectra ◽  
X Ray ◽  
Increasing Trend ◽  
Substrate Temperatures ◽  
Beam Technique

The Ti/SnO2 interface has been investigated in situ via the technique of x-ray photoelectron spectroscopy. Thin films (in the range from 0.3 to 1.1 nm) of titanium were deposited on SnO2 substrates via the e-beam technique. The deposition was carried out at two different substrate temperatures, namely room temperature and 200 °C. The photoelectron spectra of tin and titanium in the samples were found to exhibit significant differences upon comparison with the corresponding elemental and the oxide spectra. These changes result from chemical interaction between SnO2 and the titanium overlayer at the interface. The SnO2 was observed to be reduced to elemental tin while the titanium overlayer was observed to become oxidized. Complete reduction of SnO2 to elemental tin did not occur even for the lowest thickness of the titanium overlayer. The interfaces in both the types of the samples were observed to consist of elemental Sn, SnO2, elemental titanium, TiO2, and Ti-suboxide. The relative percentages of the constituents at the interface have been estimated by curve fitting the spectral data with the corresponding elemental and the oxide spectra. In the 200 °C samples, thermal diffusion of the titanium overlayer was observed. This resulted in the complete oxidation of the titanium overlayer to TiO2 upto a thickness of 0.9 nm of the overlayer. Elemental titanium resulting from the unreacted overlayer was observed to be more in the room temperature samples. The room temperature samples showed variation around 20% for the Ti-suboxide while an increasing trend was observed in the 200 °C samples.

scholarly journals Fabrication of Flexible, Lightweight, Magnetic Mushroom Gills and Coral-Like MXene–Carbon Nanotube Nanocomposites for EMI Shielding Application

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 519 ◽  
Author(s):  
Kanthasamy Raagulan ◽  
Ramanaskanda Braveenth ◽  
Lee Ro Lee ◽  
Joonsik Lee ◽  
Bo Kim ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Photoelectron Spectroscopy ◽  
Electromagnetic Interference ◽  
Sodium Dodecyl ◽  
Spray Coating ◽  
Emi Shielding ◽  
X Ray ◽  
Good Thermal Stability ◽  
Potential Applications ◽  
Oxidized Carbon

MXenes, carbon nanotubes, and nanoparticles are attractive candidates for electromagnetic interference (EMI) shielding. The composites were prepared through a filtration technique and spray coating process. The functionalization of non-woven carbon fabric is an attractive strategy. The prepared composite was characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX), and Raman spectroscopy. The MXene-oxidized carbon nanotube-sodium dodecyl sulfate composite (MXCS) exhibited 50.5 dB (99.999%), and the whole nanoparticle-based composite blocked 99.99% of the electromagnetic radiation. The functionalization increased the shielding by 15.4%. The composite possessed good thermal stability, and the maximum electric conductivity achieved was 12.5 S·cm−1. Thus, the composite shows excellent potential applications towards the areas such as aeronautics, mobile phones, radars, and military.

X-Ray photoelectron spectroscopy of monosubstituted perfluorobenzenes

1977 ◽  
Vol 55 (8) ◽  
pp. 1279-1284 ◽  
Author(s):  
Barry C. Trudell ◽  
S. James W. Price
Keyword(s):  
Gas Phase ◽  
Photoelectron Spectroscopy ◽  
Binding Energies ◽  
Photoelectron Spectra ◽  
Atomic Charges ◽  
X Ray ◽  
Sophisticated Analysis ◽  
Charge Calculations

The gas phase X-ray photoelectron spectra, XPS, were observed for the series C6F5X (X = F, Cl, I, Br, H). Binding energies were determined from the spectra using the ESCAPLOT Program. Charge calculations were carried out using Equalization of Electronegativity, CNDO/2, and ACHARGE approaches on each molecule. The more sophisticated analysis leads to the following equation correlating the (C 1s) binding energies and the atomic charges qi[Formula: see text]

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