Ultrathin Dielectric Films Grown by Solid Phase Reaction of Pr with SiO2

2004 ◽  
Vol 811 ◽  
Author(s):  
Hans-Joachim Müssig ◽  
Jarek Dąbrowski ◽  
Christian Wenger ◽  
Grzegorz Łupina ◽  
Roland Sorge ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Solid Phase ◽  
High Vacuum ◽  
Ultra High Vacuum ◽  
Dielectric Films ◽  
Solid Phase Reaction ◽  
Phase Reaction

ABSTRACTWe have fabricated Pr-based high-k gate dielectric films by physical vapor deposition of metallic Pr on SiO2 under ultra-high vacuum (UHV) conditions at room temperature, followed by oxidation and annealing steps. The films have been analyzed by electrical measurements, X-ray Photoelectron Spectroscopy (XPS) and Transmission Electron Microscopy (TEM). Some insight into the physical processes involved has been obtained from ab initio calculations. The high-k gate stacks consist of a SiO2-based buffer with an enhanced dielectric constant and a Pr silicate barrier with a high dielectric constant. The role of the buffer is to preserve the high quality of the SiO2/Si(001) interface, and the role of the barrier is to keep the tunneling currents low by increasing its physical thickness. A Pr film deposited on a 1.8 nm SiO2 layer, oxidized at room temperature by air, and annealed in N2 atmosphere with O2 partial pressure of 10−3 mbar results in a stack with the Capacitance Equivalent Thickness of 1.5 nm and leakage of 10−4 A/cm2.

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.

Effect of Sr Doping on Piezoelectric Properties of Pb(Mn1/3Nb2/3)O3-Pb(Zr,Ti)O3 Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 201-204
Author(s):  
Bao Shan Li ◽  
Guo Rong Li ◽  
Zhi Gang Zhu ◽  
Wang Zhong Zhang ◽  
Qing Rui Yin ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Oxygen Vacancies ◽  
Piezoelectric Properties ◽  
Sintering Temperature ◽  
Solid Phase ◽  
Coupling Factor ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Pzt Ceramics

This paper aims at the determination of the effects of strontium addition on the microstructural evolution and the piezoelectric properties for Pb(Mn1/3Nb2/3)O3-Pb(Zr,Ti)O3 (PMnN-PZT) ceramics. The Sr content was chosen in the range of 2-8 mol%. These materials were prepared by the solid phase reaction of the oxides. It was found, from the experimental results, the tetragonality of the PMnN-PZT lattice and the Curie temperature decreased with Sr content; in the meantime, dielectric constant increased greatly. Dielectric constant (er) and planar coupling factor (Kp) was proven to be dependent on sintering temperature. P-E curves of PMnN-PZT system exhibited some “pinched” shape instead of the normal square-like P-E loops, illustrating presence of the oxygen vacancies by reason of the preferable substitution of the B-sites ion.

scholarly journals Room-temperature graphitization in a solid-phase reaction

RSC Advances ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 914-922
Author(s):  
Sahar Elnobi ◽  
Subash Sharma ◽  
Mona Ibrahim Araby ◽  
Balaram Paudel ◽  
Golap Kalita ◽  
...  
Keyword(s):  
Deposition Temperature ◽  
Room Temperature ◽  
Solid Phase ◽  
Solid Phase Reaction ◽  
Phase Reaction

The spontaneous graphitization for C films containing Ni NPs was attributed mainly to the increased solubility for metallic Ni NPs, and was enhanced at the deposition temperature of 50 °C.

Processing and Properties of Ferroelectric Bi4-x La xTi3O12 Ceramics

2008 ◽  
Vol 368-372 ◽  
pp. 106-108
Author(s):  
Wen Wang ◽  
Hua Ke ◽  
Deng Guo Zhang ◽  
De Chang Jia ◽  
Yu Zhou
Keyword(s):  
Dielectric Constant ◽  
Dielectric Loss ◽  
Solid Phase ◽  
Sol Gel ◽  
Cold Isostatic Pressing ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Doping Content ◽  
La Doping ◽  
Reaction Processes

Bi4-xLaxTi3O12 (BLT, x=0, 0.75, 1, 2) ceramic powders were prepared with sol-gel and solid phase reaction processes, respectively. BLT powders were synthesized after decarbonization at 300°C for 1h followed by calcination at 800°C for 2h. The ceramics synthesized with cold isostatic pressing and sintering at 1150°C exhibit a perovskite-like structure. The influence of sintering parameters and La doping content on density, microstructure and dielectric properties of the BLT were discussed. With the increase of La doping content in Bi4-xLaxTi3O12, dielectric constant increases and dielectric loss gradually decreases. The dielectric constant and dielectric loss of Bi4-xLaxTi3O12 (x=2) are 132.7 and 0.012 at 100 KHz, respectively.

scholarly journals Preparation and Properties of Co-Doped Magnesium Lanthanum Hexaluminat Blue Ceramics

Ceramics ◽  
2020 ◽  
Vol 3 (2) ◽  
pp. 235-244 ◽  
Author(s):  
Rui Guo ◽  
Qingchun Wang ◽  
Jinxiao Bao ◽  
Xiwen Song
Keyword(s):  
Room Temperature ◽  
Solid Phase ◽  
Color Stability ◽  
Effect Of Temperature ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Doping Amount ◽  
Zirconia Ceramics ◽  
A Value ◽  
Co Doped

The types of blue ceramics are monotonous, mainly alumina and zirconia ceramics, and their colors are not pure, with some green tones (−a* value is not close to 0). In this paper, aluminate blue ceramics (LaMgAl11−xCoxO19) doped with Co were prepared by the high temperature solid-phase reaction method, which enriched the blue ceramics system. The effect of Co content on the color of ceramics was studied, and the optimal doping amount of Co was found. X = 1.0 is the bluest color of the material (−b* = 35.36), and there is almost no noise effect (−a* = −2.71). By studying the effect of temperature on the system, it is found that the color effect is best when the temperature reaches 1450 °C. When the temperature exceeds 1450 °C, it can only promote the synthesis of LaMgAl11O19 phase, and has no effect on the color of ceramics samples. Based on the material’s pure and bright colors, and good color stability at room temperature, it has great potential in the decoration industry, such as the preparation of jewelry or building decoration materials.

scholarly journals Store and Release of Oxygen of Ceria-Zirconia Solid Solution Synthesized by Solid Phase Reaction at Near Room Temperature.

2001 ◽  
Vol 109 (1267) ◽  
pp. 177-180 ◽  
Author(s):  
Akihiko SUDA ◽  
Hideo SOBUKAWA ◽  
Tadashi SUZUKI ◽  
Toshio KANDORI ◽  
Yoshio UKYO ◽  
...  
Keyword(s):  
Solid Solution ◽  
Room Temperature ◽  
Solid Phase ◽  
Solid Phase Reaction ◽  
Phase Reaction

scholarly journals Features of structure, magnetic state and electrodynamic performance of SrFe12−xInxO19

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
V. A. Turchenko ◽  
S. V. Trukhanov ◽  
V. G. Kostishin ◽  
F. Damay ◽  
F. Porcher ◽  
...  
Keyword(s):  
Loss Tangent ◽  
Room Temperature ◽  
Solid Phase ◽  
Spontaneous Magnetization ◽  
Magnetic Loss ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Low Frequencies ◽  
Cell Parameters ◽  
And Shifts

AbstractIndium-substituted strontium hexaferrites were prepared by the conventional solid-phase reaction method. Neutron diffraction patterns were obtained at room temperature and analyzed using the Rietveld methods. A linear dependence of the unit cell parameters is found. In3+ cations are located mainly in octahedral positions of 4fVI and 12 k. The average crystallite size varies within 0.84–0.65 μm. With increasing substitution, the TC Curie temperature decreases monotonically down to ~ 520 K. ZFC and FC measurements showed a frustrated state. Upon substitution, the average and maximum sizes of ferrimagnetic clusters change in the opposite direction. The Mr remanent magnetization decreases down to ~ 20.2 emu/g at room temperature. The Ms spontaneous magnetization and the keff effective magnetocrystalline anisotropy constant are determined. With increasing substitution, the maximum of the ε/ real part of permittivity decreases in magnitude from ~ 3.3 to ~ 1.9 and shifts towards low frequencies from ~ 45.5 GHz to ~ 37.4 GHz. The maximum of the tg(α) dielectric loss tangent decreases from ~ 1.0 to ~ 0.7 and shifts towards low frequencies from ~ 40.6 GHz to ~ 37.3 GHz. The low-frequency maximum of the μ/ real part of permeability decreases from ~ 1.8 to ~ 0.9 and slightly shifts towards high frequencies up to ~ 34.7 GHz. The maximum of the tg(δ) magnetic loss tangent decreases from ~ 0.7 to ~ 0.5 and shifts slightly towards low frequencies from ~ 40.5 GHz to ~ 37.7 GHz. The discussion of microwave properties is based on the saturation magnetization, natural ferromagnetic resonance and dielectric polarization types.

XPS, AES and Leed Studies of The Interaction Between The Si(100) 2×1 Surface and Cadmium Deposited at Room Temperature

1995 ◽  
Vol 382 ◽  
Author(s):  
S. Santucci ◽  
S. Di Nardo ◽  
L. Lozzi ◽  
M. Passacantando ◽  
P. Picozzi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Thermal Evaporation ◽  
Early Stage ◽  
High Vacuum ◽  
Amorphous Structure ◽  
Ultra High Vacuum ◽  
Energy Position ◽  
X Ray

ABSTRACTVery thin films of cadmium, with a mean thickness between 1 Å and 500 Å, were deposited by thermal evaporation in ultra-high-vacuum on a Si(100) 2×1 surface held at room temperature. In situ X-ray Photoelectron Spectroscopy and Auger Electron Spectroscopy were performed in order to investigate the interaction between the silicon substrate and the deposited cadmium. In samples with deposited mean thickness up to 3 Å, cadmium and silicon are found to be strongly interacting. In fact both XPS and AES spectra show evident changes in shape and energy position leading to the conclusion that a chemical compound between Cd and Si is formed. No diffusion between cadmium and silicon is observed, so the cadmium atoms deposited after the first 3 Å show a bulk character. The analysis of the first derivative intensity of the Si L23VV and Cd M5N45N45 Auger signals, varying the amount of deposited Cd, indicates the formation of islands in the early stage of the Cd growth. These islands show an amorphous structure as observed by using the LEED spectroscopy.

Facile composite synthesis and photoluminescence of NaGd(MoO4)2: Ln3+ (Ln = Eu, Tb) submicrometer phosphors

2009 ◽  
Vol 24 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Bing Yan ◽  
Jianhua Wu
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Solid Phase ◽  
Hydrothermal Process ◽  
Reaction Process ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Average Grain Size ◽  
Temperature And Humidity ◽  
Crystalline Water

NaGd(MoO4)2:Ln3+ (Ln = Eu, Tb) submicrometer phosphors have been synthesized by a composite method including the solid state reaction process at room temperature and the hydrothermal process. It is revealed that temperature and humidity have an influence on the reaction rate and that higher temperature and humidity can speed up the reaction process. Crystalline water is necessary for the solid phase reaction at room temperature. The x-ray diffraction (XRD) patterns indicate that NaGd(MoO4)2:Ln3+ (Ln = Eu, Tb) submicrometer phosphors crystallize well with the scheelite structure. Both scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images illustrate that the average grain size of NaGd(MoO4)2:Ln3+ is about 225 nm without conglomeration. The luminescent lifetime and quantum efficiency for NaGd(MoO4)2:Eu3+ are determined.

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