XPS STUDIES OF THE STABILITY OF A ZIRCONIUM CARBIDE FILM IN THE PRESENCE OF ZIRCONIUM OXIDE AND HYDROGEN

1995 ◽  
Vol 02 (03) ◽  
pp. 297-303 ◽  
Author(s):  
P.C. WONG ◽  
Y.S. LI ◽  
K.A.R. MITCHELL

X-ray photoelectron spectroscopy (XPS) has been used to study the interfacial chemistries of a 65-Å film prepared by depositing zirconium in an oxidizing environment onto a methane-pretreated 11-Å thick zirconium oxide film, which initially was deposited onto a gold substrate. The second metal deposition results in an outermost region composed of a mixed zirconium oxide, while below there is metallic zirconium followed by zirconium carbide and carbon on top of the first zirconium oxide film, which is itself in contact with the gold. The carbide component showed no changes on heating to 425°C, on treating with a hydrogen plasma at room temperature, or on heating the resulting film to 425°C. The oxide layers do show characteristic changes, and this also contrasts with earlier observations for a zirconium sulphide film. The zirconium carbide Zr3d 5/2 component has a binding energy of 180.6 eV.

2000 ◽  
Vol 612 ◽  
Author(s):  
J. S. Pan ◽  
A. T. S. Wee ◽  
C. H. A. Huan ◽  
J. W. Chai ◽  
J. H. Zhang

AbstractTantalum (Ta) thin films of 35 nm thickness were investigated as diffusion barriers as well as adhesion-promoting layers between Cu and SiO2 using X-ray diffractometry (XRD), Scanning electron microscopy (SEM), Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). After annealing at 600°C for 1h in vacuum, no evidence of interdiffusion was observed. However, XPS depth profiling indicates that elemental Si appears at the Ta/SiO2 interface after annealing. In-situ XPS studies show that the Ta/SiO2 interface was stable until 500°C, but about 32% of the interfacial SiO2 was reduced to elemental Si at 600°C. Upon cooling to room temperature, some elemental Si recombined to form SiO2 again, leaving only 6.5% elemental Si. Comparative studies on the interface chemical states of Cu/SiO2 and Ta/SiO2 indicate that the stability of the Cu/Ta/SiO2/Si system may be ascribed to the strong bonding of Ta and SiO2, due to the reduction of SiO2 through Ta oxide formation.


2019 ◽  
Vol 944 ◽  
pp. 613-618
Author(s):  
Yao Hua Xu ◽  
Yao Zong Sui ◽  
Xiao Zhang ◽  
Hao Liu ◽  
Peng Yuan ◽  
...  

In order to study the activation process and mechanism of ZrCoCe, highly porous ZrCoCe getter films were grown by the DC magnetron sputtering method. The effect of activation temperature on the surface composition of the porous ZrCoCe getter films were studied by X-ray photoelectron spectroscopy (XPS). The results shows that the surface of air-exposed porous ZrCoCe film is covered with H2O, CO2 and hydrocarbons, both Zr and Ce exist in the oxidized state, and zirconium oxide starts to reduce at 300 °C. The activation process also results in a sizable Co segregation at surface. In addition, zirconium carbide can be found in the subsurface region of the film after thermal activation treatment.


1995 ◽  
Vol 02 (02) ◽  
pp. 165-169 ◽  
Author(s):  
P.C. WONG ◽  
Y.S. LI ◽  
M.Y. ZHOU ◽  
K.A.R. MITCHELL

A 25 Å film formed by depositing zirconium (~2 Å min –1) onto gold foil in the presence of H 2 S (~5×10−8 mbar ) and H 2 O (~1×10−9 mbar ) has been studied by XPS. This film has an outer region composed of a mixed zirconium oxide/sulphide, while below there is metallic zirconium plus Zr/Au alloy in contact with gold. This film appears stable on heating to 400°C under UHV insofar as the sulphide part does not change, although the oxide part increases apparently as a result of some reaction of metallic zirconium with ambient water. By contrast, when this preheated film at room temperature was treated with a hydrogen plasma, the sulphide component was completely removed and the whole film was converted to the ZrO 2-like form with enhanced formation of OH groups. The hydrogen plasma treatment is therefore capable of desulphurizing the mixed zirconium oxide/sulphide film.


2007 ◽  
Vol 330-332 ◽  
pp. 557-560 ◽  
Author(s):  
Y. Xu ◽  
Nan Huang ◽  
Hong Sun

In this work, nonstoicheometric titanium oxide film on silicon matrix was prepared by unbalanced reactive pulsed magnetron sputtering /hydrogen plasma reduction method. The film chemical composition was analyzed by X-ray diffraction and X-ray photoelectron spectroscopy (XPS). The XRD patterns of the prepared films showed that titanium oxide films possess the single phase rutile structure . the XPS spectra of the film displayed that the valence state of Ti is Ti4+, Ti3+ and Ti2+ respectively and the films were nonstoichiomeric Ti-O film. The evidence showed that isolated oxygen exist in films. Ti/O ratio of Ti-O film from the XPS data vary with depth under different reduction temperature and time. And it corresponded with platelet adhesion tests of Ti-O film in vitro. Antithrombotic property of reduced titanium oxide thin films was examined by platelet adhesion tests. The results showed that the Ti-O films with lower non-stoicheometrical extent posses the better anticoagulation property than stoichiomeric TiO2 film and the Ti-O films with higher non-stoicheometrical extent. Hence hydrogen introducing is an effective way to improve the bloodcompatibility of titanium oxide film.


2005 ◽  
Vol 879 ◽  
Author(s):  
Scott K. Stanley ◽  
John G. Ekerdt

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.


Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 558
Author(s):  
Wenhui Zhu ◽  
Caiyun Zhang ◽  
Yali Chen ◽  
Qiliang Deng

Photothermal materials are attracting more and more attention. In this research, we synthesized a ferrocene-containing polymer with magnetism and photothermal properties. The resulting polymer was characterized by Fourier-transform infrared (FT-IR), vibrating sample magnetometer (VSM), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Its photo-thermocatalytic activity was investigated by choosing methylene blue (MB) as a model compound. The degradation percent of MB under an irradiated 808 nm laser reaches 99.5% within 15 min, and the degradation rate is 0.5517 min−1, which is 145 times more than that of room temperature degradation. Under irradiation with simulated sunlight, the degradation rate is 0.0092 min−1, which is approximately 2.5 times more than that of room temperature degradation. The present study may open up a feasible route to degrade organic pollutants.


Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1141
Author(s):  
Georgia Basina ◽  
Hafsa Khurshid ◽  
Nikolaos Tzitzios ◽  
George Hadjipanayis ◽  
Vasileios Tzitzios

Fe-based colloids with a core/shell structure consisting of metallic iron and iron oxide were synthesized by a facile hot injection reaction of iron pentacarbonyl in a multi-surfactant mixture. The size of the colloidal particles was affected by the reaction temperature and the results demonstrated that their stability against complete oxidation related to their size. The crystal structure and the morphology were identified by powder X-ray diffraction and transmission electron microscopy, while the magnetic properties were studied at room temperature with a vibrating sample magnetometer. The injection temperature plays a very crucial role and higher temperatures enhance the stability and the resistance against oxidation. For the case of injection at 315 °C, the nanoparticles had around a 10 nm mean diameter and revealed 132 emu/g. Remarkably, a stable dispersion was created due to the colloids’ surface functionalization in a nonpolar solvent.


Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 522
Author(s):  
Zhi Yan Lee ◽  
Huzein Fahmi bin Hawari ◽  
Gunawan Witjaksono bin Djaswadi ◽  
Kamarulzaman Kamarudin

A tin oxide (SnO2) and reduced graphene oxide (rGO) hybrid composite gas sensor for high-performance carbon dioxide (CO2) gas detection at room temperature was studied. Since it can be used independently from a heater, it emerges as a promising candidate for reducing the complexity of device circuitry, packaging size, and fabrication cost; furthermore, it favors integration into portable devices with a low energy density battery. In this study, SnO2-rGO was prepared via an in-situ chemical reduction route. Dedicated material characterization techniques including field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS) were conducted. The gas sensor based on the synthesized hybrid composite was successfully tested over a wide range of carbon dioxide concentrations where it exhibited excellent response magnitudes, good linearity, and low detection limit. The synergistic effect can explain the obtained hybrid gas sensor’s prominent sensing properties between SnO2 and rGO that provide excellent charge transport capability and an abundance of sensing sites.


2002 ◽  
Vol 16 (06n07) ◽  
pp. 1047-1051
Author(s):  
JIANPING MA ◽  
ZHIMING CHEN ◽  
GANG LU ◽  
MINGBIN YU ◽  
LIANMAO HANG ◽  
...  

Intense photoluminescence (PL) has been observed at room temperature from the polycrystalline SiC samples prepared from carbon-saturated Si melt at a temperature ranging from 1500 to 1650°C. Composition and structure of the samples have been confirmed by means of X-ray photoelectron spectroscopy, X-ray diffraction and scanning electron microscopy. PL measurements with 325 nm UV light excitation revealed that the room temperature PL spectrum of the samples consists of 3 luminescent bands, the peak energies of which are 2.38 eV, 2.77 eV and 3.06 eV, respectively. The 2.38 eV band is much stronger than the others. It is suggested that some extrinsic PL mechanisms associated with defect or interface states would be responsible to the intensive PL observed at room temperature.


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