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.

scholarly journals Thermal Stability of Octadecyltrichlorosilane and Perfluorooctyltriethoxysilane Monolayers on SiO2

Nanomaterials ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 210
Author(s):  
Xiangdong Yang ◽  
Haitao Wang ◽  
Peng Wang ◽  
Xuxin Yang ◽  
Hongying Mao
Keyword(s):  
Thermal Stability ◽  
Thermal Behavior ◽  
Work Function ◽  
Photoelectron Spectroscopy ◽  
Vacuum Annealing ◽  
Moderate Temperature ◽  
Ultraviolet Photoelectron Spectroscopy ◽  
X Ray ◽  
Thermal Stability Of

Using in situ ultraviolet photoelectron spectroscopy (UPS) and X-ray photoelectron spectroscopy (XPS) measurements, the thermal behavior of octadecyltrichlorosilane (OTS) and 1H, 1H, 2H, and 2H-perfluorooctyltriethoxysilane (PTES) monolayers on SiO2 substrates has been investigated. OTS is thermally stable up to 573 K with vacuum annealing, whereas PTES starts decomposing at a moderate temperature between 373 K and 423 K. Vacuum annealing results in the decomposition of CF3 and CF2 species rather than desorption of the entire PTES molecule. In addition, our UPS results reveal that the work function (WF)of OTS remains the same after annealing; however WF of PTES decreases from ~5.62 eV to ~5.16 eV after annealing at 573 K.

scholarly journals “PdO vs. PtO”—The Influence of PGM Oxide Promotion of Co3O4 Spinel on Direct NO Decomposition Activity

Catalysts ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 62 ◽  
Author(s):  
Gunugunuri K. Reddy ◽  
Torin C. Peck ◽  
Charles A. Roberts
Keyword(s):  
Photoelectron Spectroscopy ◽  
No Decomposition ◽  
Single Element ◽  
X Ray Diffraction ◽  
X Ray ◽  
Promotional Effect ◽  
Ft Ir ◽  
Temperature Programmed ◽  
Thermal Stability Of

Direct decomposition of NO into N2 and O2 (2NO→N2 + O2) is recognized as the “ideal” reaction for NOx removal because it needs no reductant. It was reported that the spinel Co3O4 is one of the most active single-element oxide catalysts for NO decomposition at higher reaction temperatures, however, activity remains low below 650 °C. The present study aims to investigate new promoters for Co3O4, specifically PdO vs. PtO. Interestingly, the PdO promoter effect on Co3O4 was much greater than the PtO effect, yielding a 4 times higher activity for direct NO decomposition at 650 °C. Also, Co3O4 catalysts with the PdO promoter exhibit higher selectivity to N2 compared to PtO/Co3O4 catalysts. Several characterization measurements, including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H2-temperature programmed reduction (H2-TPR), and in situ FT-IR, were performed to understand the effect of PdO vs. PtO on the properties of Co3O4. Structural and surface analysis measurements show that impregnation of PdO on Co3O4 leads to a greater ease of reduction of the catalysts and an increased thermal stability of surface adsorbed NOx species, which contribute to promotion of direct NO decomposition activity. In contrast, rather than remaining solely as a surface species, PtO enters the Co3O4 structure, and it promotes neither redox properties nor NO adsorption properties of Co3O4, resulting in a diminished promotional effect compared to PdO.

scholarly journals Probing surfaces and interfaces in complex oxide films via in situ X-ray photoelectron spectroscopy

2020 ◽  
pp. 1-26
Author(s):  
Suresh Thapa ◽  
Rajendra Paudel ◽  
Miles D. Blanchet ◽  
Patrick T. Gemperline ◽  
Ryan B. Comes
Keyword(s):  
Photoelectron Spectroscopy ◽  
Oxide Films ◽  
Complex Oxide ◽  
X Ray ◽  
Surfaces And Interfaces ◽  
Complex Oxide Films

Abstract

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.

scholarly journals In situ metalation of free base phthalocyanine covalently bonded to silicon surfaces

2014 ◽  
Vol 5 ◽  
pp. 2222-2229 ◽  
Author(s):  
Fabio Lupo ◽  
Cristina Tudisco ◽  
Federico Bertani ◽  
Enrico Dalcanale ◽  
Guglielmo G Condorelli
Keyword(s):  
Porous Silicon ◽  
Photoelectron Spectroscopy ◽  
Relevant Information ◽  
Silicon Surfaces ◽  
Porous Si ◽  
Wet Chemistry ◽  
X Ray ◽  
Covalently Bonded ◽  
Phthalocyanine Ring

Free 4-undecenoxyphthalocyanine molecules were covalently bonded to Si(100) and porous silicon through thermic hydrosilylation of the terminal double bonds of the undecenyl chains. The success of the anchoring strategy on both surfaces was demonstrated by the combination of X-ray photoelectron spectroscopy with control experiments performed adopting the commercially available 2,3,9,10,16,17,23,24-octakis(octyloxy)-29H,31H-phthalocyanine, which is not suited for silicon anchoring. Moreover, the study of the shape of the XPS N 1s band gave relevant information on the interactions occurring between the anchored molecules and the substrates. The spectra suggest that the phthalocyanine ring interacts significantly with the flat Si surface, whilst ring–surface interactions are less relevant on porous Si. The surface-bonded molecules were then metalated in situ with Co by using wet chemistry. The efficiency of the metalation process was evaluated by XPS measurements and, in particular, on porous silicon, the complexation of cobalt was confirmed by the disappearance in the FTIR spectra of the band at 3290 cm−1 due to –NH stretches. Finally, XPS results revealed that the different surface–phthalocyanine interactions observed for flat and porous substrates affect the efficiency of the in situ metalation process.

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.

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