Role of Oxygen in Growth of Carbon Nanotubes on SiC

2006 ◽  
Vol 527-529 ◽  
pp. 1575-1578 ◽  
Author(s):  
Wei Jie Lu ◽  
John Boeckl ◽  
W.C. Mitchel ◽  
J. Rigueur ◽  
W.E. Collins
Keyword(s):  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Structural Defects ◽  
Oxygen Species ◽  
Oxygen Compound ◽  
X Ray ◽  
Multi Wall Carbon Nanotubes

Carbon nanotubes (CNTs) grown on SiC are metal-free, well-aligned, and with low structural defects. In this study, CNT formation on SiC is examined in high vacuum (10-5torr) and ultra-high vacuum (10-8torr). Multi-wall carbon nanotubes and graphitic structures are the main products on the SiC surface at 1400-1800°C in 10-5torr. Under ultra-high vacuum, the decomposition rate of SiC is much lower than in high vacuum, indicating that SiC is decomposed by oxidation reaction. Using X-ray photoelectron spectroscopy (XPS), the intensity of the O1s peak at 530.3 eV decreases with increasing take-off angle, indicating that this oxygen species exists on the walls of CNTs. The results show that oxygen with a low pressure not only oxidizes SiC, but also forms a highly thermally stable carbon-oxygen compound, and interacts with the CNTs at high temperatures.

Incorporation and Role of Nitrogen During Oxynitridation of Silicon Studied by Photoelectron Spectroscopy

1999 ◽  
Vol 567 ◽  
Author(s):  
Masayuki Suzuki ◽  
Yoji Saito
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Oxide Films ◽  
Silicon Surfaces ◽  
Gaseous Mixtures ◽  
X Ray ◽  
Initial Stage ◽  
Thermal Stability Of

ABSTRACTWe tried direct oxynitridation of silicon surfaces by remote-plasma-exited nitrogen and oxygen gaseous mixtures at 700°C in a high vacuum. The oxynitrided surfaces were investigated with in-situ X-ray photoelectron spectroscopy. With increase of the oxynitridation time, the surface density of nitrogen gradually increases, but that of oxygen shows nearly saturation behavior after the rapid increase in the initial stage. We also annealed the grown oxynitride and oxide films to investigate the role of the contained nitrogen. The desorption rate of oxygen from the oxynitride films is much less than that from oxide films. We confirmed that nitrogen stabilizes the thermal stability of these oxynitride films.

Multi-wall carbon nanotubes with nitrogen-containing carbon coating

2013 ◽  
Vol 67 (8) ◽  
Author(s):  
Elena Tomšík ◽  
Zuzana Morávková ◽  
Jaroslav Stejskal ◽  
Miroslava Trchová ◽  
Petr Šálek ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Photoelectron Spectroscopy ◽  
Carbon Coating ◽  
Covalent Bonding ◽  
Inert Atmosphere ◽  
New Materials ◽  
X Ray ◽  
Multi Wall Carbon Nanotubes ◽  
Transmission Electron

AbstractPolyaniline coating was deposited on the surface of multi-wall carbon nanotubes of Russian and Taiwanese origin in situ during the polymerization of aniline. The deposited polyaniline film was subsequently carbonized under an inert atmosphere at various temperatures to produce coaxial coating of the carbon nanotubes with nitrogen-containing carbon. The new materials were investigated by infrared and Raman spectroscopies, which demonstrated the conversion of the polyaniline coating to a carbonized structure. X-ray photoelectron spectroscopy proved that the carbonized overlayer contains nitrogen atoms in various covalent bonding states. Transmission electron microscopy confirmed the coaxial structure of the composites. The Brunauer-Emmett-Teller method was used to estimate the specific surface area, the highest being 272 m2 g−1. The conductivity of 0.9–16 S cm−1 was measured by the four-point method, and it was only a little affected by the carbonization of the polyaniline coating.

Fundamental study of the interaction of Ti atoms with spruce surfaces

Holzforschung ◽  
2007 ◽  
Vol 61 (5) ◽  
pp. 523-527 ◽  
Author(s):  
Lothar Klarhöfer ◽  
Florian Voigts ◽  
Dominik Schwendt ◽  
Burkhard Roos ◽  
Wolfgang Viöl ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Strong Interactions ◽  
Titanium Oxide Film ◽  
Fundamental Study ◽  
X Ray ◽  
Force Microscopy ◽  
Atomic Force ◽  
Metal Atoms

Abstract Metastable induced electron spectroscopy (MIES), ultraviolet photoelectron spectroscopy (UPS), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) were applied to study the interaction of Ti metal atoms with spruce surfaces. Spruce surfaces were produced by planing splints from a spruce bar. Ti atoms were adsorbed from a metal evaporator under ultra-high vacuum conditions. The amount adsorbed corresponds to 10 monolayer equivalents. Strong interactions between the spruce surface and metals atoms occurred. Impinging Ti atoms were oxidized by the spruce surface. No Ti agglomeration or particle formation was observed. The surface was smoothed by the Ti applied and was completely covered by a titanium oxide film.

CORRELATION AMONG THE ELECTRONIC STATE IN Sn-DOPED YBCO SYSTEM

1991 ◽  
Vol 05 (08) ◽  
pp. 581-585
Author(s):  
H. ZHANG ◽  
S.Q. FENG ◽  
Q.R. FENG ◽  
X. ZHU
Keyword(s):  
Content Analysis ◽  
Binding Energy ◽  
Photoelectron Spectroscopy ◽  
Strong Correlation ◽  
Single Phase ◽  
Vacuum Chamber ◽  
High Vacuum ◽  
Electronic States ◽  
Ultra High Vacuum ◽  
X Ray

We have performed an X-ray photoelectron spectroscopy investigation on single-phase samples of Sn -doped YBCO system, together with structure analysis, oxygen content analysis, and superconductivity measurements. The experiment gave evidence that there is a strong correlation between the electronic states of copper and oxygen. When the sample was heated to 600°C for 20 minutes in vacuum chamber, the oxygen escaped from the sample, the binding energy of Cu 2p was decreased, and the two indistinct components of O 1s became clear. Keeping the sample in ultra-high vacuum for 24 hours, a similar result was obtained.

scholarly journals Investigation of interaction of Co, Mn and Fe atoms with the calcite by X-ray photoelectron spectroscopy

2019 ◽  
Vol 64 (1) ◽  
pp. 89-95
Author(s):  
T. T. Magkoev ◽  
V. B. Zaalishvili ◽  
O. G. Burdzieva ◽  
G. E. Tuaev ◽  
G. S. Grigorkina
Keyword(s):  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
X Ray ◽  
Surface Compounds ◽  
Adsorption Systems

Adsorption of atoms of Co, Mn, Fe on the calcite surface in ultra-high vacuum and the interaction of the formed adsorption systems with the water have been studied by means of X-ray photoelectron spectroscopy. It is shown that Mn and Fe form solid solutions CaCO3/Mn(Fe)CO3 on the calcite surface, whereas Co preferentially forms CoO and Co3O4. Upon interaction with water the surface compounds formed by Mn and Fe do not undergo notable changes, unlike the Co oxides which partially transform into soluble hydroxylated complexes.

scholarly journals Growth Mode Study of MgCl2 on Ti (0001) and SiO2 under Ultra High Vacuum by XPS

2012 ◽  
Vol 2 (6) ◽  
pp. 291-294
Author(s):  
S. Karakalos
Keyword(s):  
Single Crystal ◽  
Photoelectron Spectroscopy ◽  
Magnesium Chloride ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Growth Mode ◽  
X Ray ◽  
Mode Study

The growth mode of MgCl2 on Ti (0001) and on SiO2 grown on Si (100) was investigated by X-ray Photoelectron Spectroscopy (XPS) under UHV conditions. Magnesium chloride grows on both Ti (0001) single crystal and SiO2 following the Frank-van der Merve, (FM) growth mode.

scholarly journals Selective Growth of Al2O3 on Size-Selected Platinum Clusters by Atomic Layer Deposition

2019 ◽  
Author(s):  
Timothy J. Gorey ◽  
Yang Dai ◽  
Scott Anderson ◽  
Sungsik Lee ◽  
Sungwon Lee ◽  
...  
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Atomic Layer ◽  
Ultra High Vacuum ◽  
Ex Situ ◽  
Dimensional Structure ◽  
Alumina Layer ◽  
X Ray ◽  
Layer Deposition

In heterogeneous catalysis, atomic layer deposition (ALD) has been developed as a tool to stabilize and reduce carbon deposition on supported nanoparticles. Here, we discuss use of high vacuum ALD to deposit alumina films on size-selected, sub-nanometer Pt/SiO2 model catalysts. Mass-selected Pt24 clusters were deposited on oxidized Si(100), to form model Pt24/SiO2 catalysts with particles shown to be just under 1 nm, with multilayer three dimensional structure. Alternating exposures to trimethylaluminum and water vapor in an ultra-high vacuum chamber were used to grow alumina on the samples without exposing them to air. The samples were probed in situ using X-ray photoelectron spectroscopy (XPS), low-energy ion scattering spectroscopy (ISS), and CO temperature-programmed desorption (TPD). Additional samples were prepared for ex situ experiments using grazing incidence small angle x-ray scattering spectroscopy (GISAXS). Alumina growth is found to initiate at least 60 times more efficiently at the Pt24 cluster sites, compared to bare SiO2/Si, with a single ALD cycle depositing a full alumina layer on top of the clusters, with substantial additional alumina growth initiating on SiO2 sites surrounding the clusters. As a result, the clusters were completely passivated, with no exposed Pt binding sites.

scholarly journals Microstructure and Optical Properties of E-Beam Evaporated Zinc Oxide Films—Effects of Decomposition and Surface Desorption

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3510
Author(s):  
Lukasz Skowronski ◽  
Arkadiusz Ciesielski ◽  
Aleksandra Olszewska ◽  
Robert Szczesny ◽  
Mieczyslaw Naparty ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Oxide Films ◽  
Growth Direction ◽  
Ultra High Vacuum ◽  
X Ray ◽  
Force Microscopy ◽  
Zinc Oxide Films

Zinc oxide films have been fabricated by the electron beam physical vapour deposition (PVD) technique. The effect of substrate temperature during fabrication and annealing temperature (carried out in ultra high vacuum conditions) has been investigated by means of atomic force microscopy, scanning electron microscopy, powder X-ray diffraction, X-ray photoelectron spectroscopy and spectroscopic ellipsometry. It was found that the layer deposited at room temperature is composed of Zn and ZnO crystallites with a number of orientations, whereas those grown at 100 and 200 ∘C consist of ZnO grains and exhibit privileged growth direction. Presented results clearly show the influence of ZnO decomposition and segregation of Zn atoms during evaporation and post-deposition annealing on microstructure and optical properties of zinc oxide films.

Temperature Induced Phase Transformation on the 4H-SiC(11-20) Surface

2006 ◽  
Vol 527-529 ◽  
pp. 673-676 ◽  
Author(s):  
W.Y. Lee ◽  
S. Soubatch ◽  
Ulrich Starke
Keyword(s):  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Vacuum System ◽  
X Ray ◽  
Force Microscopy ◽  
Low Energy Electron Diffraction ◽  
Atomic Force ◽  
Surface Phases ◽  
Low Energy Electron

The atomic structure of the 4H-SiC(11 2 0) surface including possible phase transformations via Si deposition and annealing has been investigated using low energy electron diffraction (LEED), Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The sample is initially prepared by hydrogen etching before loading into the ultra-high vacuum system. The sample is then out-gassed to remove oxygen from the surface. To explore the existence of ordered surface phases, Si is deposited on the sample at 850°C for 15 minutes followed by a series of sequential annealing steps. Throughout this process, the surface is monitored by LEED, AES and XPS. LEED shows that the surface continuously maintains a (1×1) periodicity. Yet, two unique and distinguishable (1×1) phases can be identified. The changes between these phases are clearly demonstrated by the LEED spot intensities. Simultaneously, the Auger and XPS data show a decrease in Si intensity.

Rapid Assay for Polystyrene Surface Oxidation

1993 ◽  
Vol 47 (10) ◽  
pp. 1609-1611 ◽  
Author(s):  
M. Bryhan ◽  
E. C. Onyiriuka ◽  
L. S. Hersh ◽  
W. Hertl
Keyword(s):  
Corona Discharge ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Surface Oxidation ◽  
Ultra High Vacuum ◽  
Surface Oxygen ◽  
Simple Method ◽  
Absorbance Measurement ◽  
X Ray ◽  
Polystyrene Surface

Polystyrene surfaces are often corona-discharge or plasma treated to oxidize the surface, which enhances the wettability. X-ray photoelectron spectroscopy (XPS), which requires time and an ultra-high vacuum, is generally used to measure this surface oxidation. A rapid, simple method for measuring polystyrene surface oxidation is described. The surface is soaked in a solution of Azure A dye, which adsorbs only to oxidized sites on the polystyrene. The excess dye is flushed away and the bound dye is desorbed with a detergent; an absorbance measurement at 635 nm is used to determine the quantity of desorbed dye. This value correlates with the polystyrene surface oxygen concentration and gives r2 = 0.93.

Sign in / Sign up

Export Citation Format

Share Document