Composition and Chemical Structure of Nitrided Silica Gel

1984 ◽  
Vol 32 ◽  
Author(s):  
R. K. Brow ◽  
C. G. Pantano
Keyword(s):  
Thin Films ◽  
Infrared Spectroscopy ◽  
Low Temperature ◽  
Silica Gel ◽  
Photoelectron Spectroscopy ◽  
Chemical Structure ◽  
Sol Gel ◽  
X Ray ◽  
Higher Temperature ◽  
Low Temperature Treatments

ABSTRACTSol/gel derived silica thin films were thermally treated in NH3 for four hours at temperatures up to 1300C. The films were analyzed by ellipsometry, X-ray photoelectron spectroscopy (XPS) and infrared spectroscopy (IR). Over 30 mol% nitrogen was incorporated in the film treated at 1300C. Using IR and XPS analyses, -NHx groups were found to be present after low temperature treatments, while nitrogen was incorporated in an oxynitride structure after the higher temperature treatments.

Thermochromic VO2 Thin Film Prepared by Post Annealing Treatment of V2O5 Thin Film

2009 ◽  
Vol 79-82 ◽  
pp. 747-750 ◽  
Author(s):  
Dong Qing Liu ◽  
Wen Wei Zheng ◽  
Hai Feng Cheng ◽  
Hai Tao Liu
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Phase Transition ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Annealing Treatment ◽  
Simple Method ◽  
X Ray ◽  
Post Annealing ◽  
Vo2 Thin Films

Thermochromic vanadium dioxide (VO2) exhibits a semi-conducting to metallic phase transition at about 68°C, involving strong variations in electrical and optical properties. A simple method was proposed to prepare VO2 thin films from easily gained V2O5 thin films. The detailed thermodynamic calculation was done and the results show that V2O5 will decompose to VO2 when the post annealing temperature reaches 550°C at the atmospheric pressure of less than 0.06Pa. The initial V2O5 films were prepared by sol-gel method on fused-quartz substrates. Different post annealing conditions were studied. The derived VO2 thin film samples were characterized using X-ray diffraction and X-ray photoelectron spectroscopy. The electrical resistance and infrared emissivity of VO2 thin films under different temperatures were measured. The results show that the VO2 thin film derived from the V2O5 thin film annealed at 550°C for 10 hours is pure dioxide of vanadium without other valences. It was observed that the resistance of VO2 thin film with thickness about 600nm can change by 4 orders of magnitude and the 7.5-14μm emissivity can change by 0.6 during the phase transition.

scholarly journals Silica-Copper Oxide Composite Thin Films as Solar Selective Coatings Prepared by Dipping Sol Gel

2008 ◽  
Vol 2008 ◽  
pp. 1-5 ◽  
Author(s):  
E. Barrera-Calva ◽  
J. Méndez-Vivar ◽  
M. Ortega-López ◽  
L. Huerta-Arcos ◽  
J. Morales-Corona ◽  
...  
Keyword(s):  
Thin Films ◽  
Stainless Steel ◽  
Copper Oxide ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Silica Matrix ◽  
Composite Thin Films ◽  
X Ray ◽  
Molar Ratios ◽  
Steel Substrates

Silica-copper oxide (silica-CuO) composite thin films were prepared by a dipping sol-gel route using ethanolic solutions comprised TEOS and a copper-propionate complex. Sols with different TEOS/Cu-propionate (Si/Cu) molar ratios were prepared and applied on stainless steel substrates using dipping process. During the annealing process, copper-propionate complexes developed into particulate polycrystalline CuO dispersed in a partially crystallized silica matrix, as indicated by the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. The gel thermal analysis revealed that the prepared material might be stable up to400°C. The silica-CuO/stainless steel system was characterized as a selective absorber surface and its solar selectivity parameters, absorptance (α), and emittance (ε) were evaluated from UV-NIR reflectance data. The solar parameters of such a system were mostly affected by the thickness and phase composition of theSiO2-CuO film. Interestingly, the best solar parameters (α= 0.92 andε= 0.2) were associated to the thinnest films, which comprised a CuO-Cu2Omixture immersed in the silica matrix, as indicated by XPS.

SiO2ZrO2 Thin Films as Low Temperature NO2 and O3 Sensors

2015 ◽  
Vol 1088 ◽  
pp. 81-85 ◽  
Author(s):  
T.N. Myasoedova ◽  
Victor V. Petrov ◽  
Nina K. Plugotarenko ◽  
Dmitriy V. Sergeenko ◽  
Galina Yalovega ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Scanning Electron Microscopy ◽  
Low Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Operating Temperatures ◽  
Scanning Electron

Thin SiO2ZrO2films were prepared, up to 0.2 μm thick, by means of the sol–gel technology and characterized by a Scanning electron microscopy and X-ray diffraction. It is shown the presence of monoclinic, cubic and tetragonal phases of ZrO2in the SiO2matrix. The crystallites sizes depend on the annealing temperature of the film and amount to 35 and 56 nm for the films annealed at 773 and 973 K, respectively. The films resistance is rather sensitive to the presence of NO2and O3impurity in air at lower operating temperatures in the range of 30-60°C.

scholarly journals Synthesis & characterization of nanostructure VO2 thin film

2021 ◽  
Vol 2070 (1) ◽  
pp. 012098
Author(s):  
P K Ojha ◽  
S K Mishra
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Vanadium Dioxide ◽  
Sol Gel ◽  
Cost Effective ◽  
Metallic Phase ◽  
Strongly Correlated ◽  
X Ray Diffraction ◽  
X Ray ◽  
Sol Gel Process

Abstract Vanadium dioxides are strongly correlated systems which undergo an insulator-metal transition (IMT) from a low-temperature semiconducting phase to a high-temperature metallic phase. Among them, Vanadium dioxide (VO2) undergoes IMT close to room temperature, accompanied by a structural transition resulting change of several orders of magnitude in the electrical and optical properties. Here, we present the synthesis of VO2 by sol-gel process which employs cost-effective precursors to synthesize pure phase of VO2 thin films. The synthesized thin films were characterized using an X-ray diffraction (XRD) to confirm phase purity and high resolution scanning electron microscope (HR-SEM) to study the crystallite and particle size for the synthesized films. The film’s surface was analyzed by X-ray photoelectron spectroscopy (XPS) to determine the valence state and chemical composition of vanadium dioxide.

scholarly journals Resistive Switching Characteristics of HfO2 Thin Films on Mica Substrates Prepared by Sol-Gel Process

Nanomaterials ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 1124 ◽  
Author(s):  
Chao-Feng Liu ◽  
Xin-Gui Tang ◽  
Lun-Quan Wang ◽  
Hui Tang ◽  
Yan-Ping Jiang ◽  
...  
Keyword(s):  
Thin Films ◽  
Resistive Switching ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Random Access ◽  
High Resistance State ◽  
X Ray ◽  
Low Resistance ◽  
Sol Gel Process ◽  
Resistance State

The resistive switching (RS) characteristics of flexible films deposited on mica substrates have rarely been reported upon, especially flexible HfO2 films. A novel flexible Au/HfO2/Pt/mica resistive random access memory device was prepared by a sol-gel process, and a Au/HfO2/Pt/Ti/SiO2/Si (100) device was also prepared for comparison. The HfO2 thin films were grown into the monoclinic phase by the proper annealing process at 700 °C, demonstrated by grazing-incidence X-ray diffraction patterns. The ratio of high/low resistance (off/on) reached 1000 and 50 for the two devices, respectively, being relatively stable for the former but not for the latter. The great difference in ratios for the two devices may have been caused by different concentrations of the oxygen defect obtained by the X-ray photoelectron spectroscopy spectra indicating composition and chemical state of the HfO2 thin films. The conduction mechanism was dominated by Ohm’s law in the low resistance state, while in high resistance state, Ohmic conduction, space charge limited conduction (SCLC), and trap-filled SCLC conducted together.

Properties of SiO2CuOx Films for Nitrogen Dioxide Detection

2013 ◽  
Vol 834-836 ◽  
pp. 112-116 ◽  
Author(s):  
Tatiana Myasoedova ◽  
G.E. Yalovega ◽  
V.V. Petrov ◽  
O.V. Zabluda ◽  
V.A. Shmatko ◽  
...  
Keyword(s):  
Thin Films ◽  
Nitrogen Dioxide ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Gel Technique ◽  
Operating Temperatures

SiOxCuOythin films were prepared by the deposition on to the Si/SiO2substrates from the alcoholic solutions employing the sol-gel technique. The various analytic techniques were applied to characterize structure and properties of the films under study . The both X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) studies showed the presence CuO as well as CuO2phases and formation of a dual-oxide CuSiO3with the average crystallites sizes of 35-50 nm. The conductance of the films was rather sensitive to the presence of 1-20 ppm NO2concentration at the operating temperatures in the range of 20–200◦C.

scholarly journals Sulfur resistance of Ce-Mn/TiO 2 catalysts for low-temperature NH 3 –SCR

2018 ◽  
Vol 5 (3) ◽  
pp. 171846 ◽  
Author(s):  
Quan Xu ◽  
Wenjing Yang ◽  
Shitong Cui ◽  
Jason Street ◽  
Yan Luo
Keyword(s):  
Low Temperature ◽  
Photoelectron Spectroscopy ◽  
Conversion Rate ◽  
Active Sites ◽  
Sol Gel ◽  
Textural Properties ◽  
Catalyst Loading ◽  
Impregnation Method ◽  
No Conversion ◽  
X Ray

Ce-Mn/TiO 2 catalyst prepared using a simple impregnation method demonstrated a better low-temperature selective catalytic reduction of NO with NH 3 (NH 3 –SCR) activity in comparison with the sol-gel method. The Ce-Mn/TiO 2 catalyst loading with 20% Ce had the best low-temperature activity and achieved a NO conversion rate higher than 90% at 140–260°C with a 99.7% NO conversion rate at 180°C. The Ce-Mn/TiO 2 catalyst only had a 6% NO conversion rate decrease after 100 ppm of SO 2 was added to the stream. When SO 2 was removed from the stream, the catalyst was able to recover completely. The crystal structure, morphology, textural properties and valence state of the metals involving the novel catalysts were investigated using X-ray diffraction, N 2 adsorption and desorption analysis, X-ray photoelectron spectroscopy, scanning electron microscopy and energy dispersive spectroscopy, respectively. The decrease of NH 3 –SCR performance in the presence of 100 ppm SO 2 was due to the decrease of the surface area, change of the pore structure, the decrease of Ce 4+ and Mn 4+ concentration and the formation of the sulfur phase chemicals which blocked the active sites and changed the valence status of the elements.

Molecular Precursors to Boron Nitride then Films: the Reactions of Diborane with Ammonia and with Hydrazine on Ru(0001)

1991 ◽  
Vol 250 ◽  
Author(s):  
Charles M. Truong ◽  
José A. Rodriguez ◽  
Ming Cheng Wu ◽  
D. W. Goodman
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Boron Nitride ◽  
Mass Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Stoichiometric Ratio ◽  
X Ray ◽  
Molecular Precursors ◽  
Temperature Deposition ◽  
Boron Nitrogen

AbstractThe coadsorption and reaction of diborane with ammonia and with hydrazine on Ru(0001) have been studied using X-ray photoelectron spectroscopy (XPS) and thermal desorption mass spectroscopy (TDS). Diborane is found to decompose to atomic boron and hydrogen upon adsorption at T>200K. Multilayers of diborane and ammonia, deposited at 90K on Ru(0001), react when annealed to 600K. The XPS results indicate that boron-nitrogen adlayers can be formed by this reaction. These boron-nitrogen films are boron-rich and.decompose at temperatures higher than 1100K. Our TDS studies reveal that hydrazine decomposes extensively to NH3, N2, N and H on Ru(0001). Due to its higher reactivity, boron-nitrogen films of B/N stoichiometric ratio near unity are obtained when hydrazine is used rather than ammonia. In our studies, these films were formed by either simultaneously dosing B2H6 and N2H4 at 450K or by coadsorption of the reactants at 90K and subsequent annealing to 450K. These studies have shown that diborane and hydrazine can be successfully used as molecular precursors in the low temperature deposition of boron nitride thin-films.

Poly(vanadium–molybdenum acid) xerogel thin films fabricated by the sol-gel process and their humidity-sensing properties

2000 ◽  
Vol 15 (12) ◽  
pp. 2653-2657 ◽  
Author(s):  
Maosong Tong ◽  
Guorui Dai ◽  
Yuanda Wu ◽  
Xiuli He ◽  
Wei Yan ◽  
...  
Keyword(s):  
Thin Films ◽  
Thermogravimetric Analysis ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Humidity Sensing ◽  
X Ray ◽  
Sensing Properties ◽  
Sol Gel Process ◽  
Humidity Sensing Properties

Thermogravimetric analysis, x-ray photoelectron spectroscopy, and x-ray diffraction results and the humidity sensing properties of poly(vanadium–molybdenum acid) H2V9.5Mo2.5O32.0 · 8.8H2O xerogel thin films, which were fabricated by the sol-gel process, are described in this paper. The conductance and the capacitance of the thin films strongly depend on the relative humidity. Different electrodes have different influences on the humidity-sensing properties of the thin films.

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