scholarly journals Phase equilibria in systems involving the rare earth oxides. Part III. The Eu2O3-In2O3 system

1961 ◽  
Vol 65A (5) ◽  
pp. 429 ◽  
Author(s):  
S. J. Schneider
Keyword(s):  
Rare Earth ◽  
Phase Equilibria ◽  
Rare Earth Oxides ◽  
The Rare Earth

The Phase Equilibria and Crystal Chemistry of the Rare Earth-Group VI Systems. IV. Lanthanum-Tellurium

1965 ◽  
Vol 4 (8) ◽  
pp. 1154-1157 ◽  
Author(s):  
T. H. Ramsey ◽  
H. Steinfink ◽  
E. J. Weiss
Keyword(s):  
Rare Earth ◽  
Phase Equilibria ◽  
Crystal Chemistry ◽  
Group Vi ◽  
The Rare Earth

Epitaxial Growth of High-κ Dielectrics for GaN MOSFETs

2008 ◽  
Vol 1068 ◽  
Author(s):  
Jesse S. Jur ◽  
Ginger D. Wheeler ◽  
Matthew T. Veety ◽  
Daniel J. Lichtenwalner ◽  
Douglas W. Barlage ◽  
...  
Keyword(s):  
Rare Earth ◽  
Epitaxial Growth ◽  
Field Effect ◽  
Field Effect Transistor ◽  
Rare Earth Oxides ◽  
Oxide Semiconductor ◽  
Native Oxide ◽  
Enhancement Mode ◽  
Effect Transistor ◽  
The Rare Earth

ABSTRACTHigh-dielectric constant (high-κ) oxide growth on hexagonal-GaN (on sapphire) is examined for potential use in enhancement-mode metal oxide semiconductor field effect transistor (MOSFET). Enhancement-mode MOSFET devices (ns > 4×1013 cm−2) offer significant performance advantages, such as greater efficiency and scalability, as compared to heterojunction field effect transistor (HFET) devices for use in high power and high frequency GaN-based devices. High leakage current and current collapse at high drive conditions suggests that the use of a high-κ insulating layer is principle for enhancement-mode MOSFET development. In this work, rare earth oxides (Sc, La, etc.) are explored due to their ideal combination of permittivity and high band gap energy. However, a substantial lattice mismatch (9-21%) between the rare earth oxides and the GaN substrate results in mid-gap defect state densities and growth dislocations. The epitaxial growth of the rare earth oxides by molecular beam epitaxy (MBE) on native oxide passivated-GaN is examined in an effort to minimize these growth related defects and other growth-related limitations. Growth of the oxide on GaN is characterized analytically by RHEED, XRD, and XPS. Preliminary MOS electrical analysis of a 50 Å La2O3 on GaN shows superior leakage performance as compared to significantly thicker Si3N4 dielectric.

On `non-stoichiometric phases' in thin films of rare-earth oxides

1978 ◽  
Vol 34 (6) ◽  
pp. 1025-1027 ◽  
Author(s):  
M. Gasgnier ◽  
P. Caro
Keyword(s):  
Thin Films ◽  
Rare Earth ◽  
Long Range ◽  
Short Range ◽  
Short Range Order ◽  
Rare Earth Oxides ◽  
Range Order ◽  
Acta Cryst ◽  
The Rare Earth

Kaul & Saxena [Acta Cryst. (1977), A33, 992-996] have reported the existence of long-range and short-range order in a non-stoichiometric phase 'LnO x ' (Ln = rare earth). It is shown that the experiments they are describing are indeed the oxidation of the rare-earth hydride LnH2 into the rare-earth cubic C-type sesquioxide. The interpretation they give of their experiments is to be discarded entirely.

Nano Crystallite ZrO2, La2O3 and CeO2: Synthesis, Characterization and their Properties

2013 ◽  
Vol 209 ◽  
pp. 212-215
Author(s):  
A.K. Patel ◽  
A.R. Umatt ◽  
B.S. Chakrabarty
Keyword(s):  
Rare Earth ◽  
Surface Area ◽  
Gas Adsorption ◽  
Chemical Properties ◽  
Rare Earth Oxide ◽  
Combustion Method ◽  
Rare Earth Oxides ◽  
Precipitation Method ◽  
Reaction Conditions ◽  
The Rare Earth

It is well known that a minor addition of rare earth oxides can provide a beneficial effect towards various catalytic reactions. Use of rare earth oxide in different applications could improve commercial productivity in an affordable way. Among the rare earth oxides, ZrO2, La2O3 and CeO2 are very interesting due to their various characteristics showing a large range of applications in organic reactions. The changes in the molecular properties of materials at the nano scale level greatly enhance their physical properties as well as chemical properties and activity. Due to the extremely small size of the particles, an increased surface area is provided to the reactant enabling more molecules to react at the same time, thereby speeding up the process. In this work, the enhancement in the catalytic activity of these nano structured rare earth oxides has been studied under different reaction conditions. Nano crystalline ZrO2, La2O3 and CeO2 samples were synthesized using precipitation method and optimum reaction conditions have been established; whereas the corresponding bulk samples were synthesized by combustion method. The identification of phase and crystalline size of synthesized oxides have been done by X-ray diffraction, the band gape of these three oxides in both the forms has been analyzed by UV absorbance and surface area has been determined by gas adsorption analysis (BET). Moreover their different properties and the activity of nano crystallite oxides have also been compared with their bulk counterparts. Even the activity of ZrO2 is also compared with the rare earth oxides La2O3 and CeO2.

Study on the calcination experiments of rare earth carbonates using microwave heating

2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Guo Lin ◽  
Libo Zhang ◽  
Shaohua Yin ◽  
Jinhui Peng ◽  
Shiwei Li ◽  
...  
Keyword(s):  
Rare Earth ◽  
Microwave Heating ◽  
Rare Earth Oxides ◽  
Particle Analysis ◽  
Scanning Calorimetry ◽  
Vibration Absorption ◽  
Ft Ir ◽  
Average Size ◽  
Rare Earth Carbonates ◽  
The Rare Earth

AbstractThe heating behavior and effect of experimental parameters like holding time, calcination temperature and microwave power on the weight loss of the mixed rare earth carbonate using microwave heating have been studied, also characterized by X-ray diffraction, thermogravimetry-differential scanning calorimetry, scanning electron microscopy (SEM), particle analysis and Fourier transform infrared (FT-IR). The results show the following: rare earth oxides are obtained at 850°C for holding 1 h; FT-IR analysis indicates that the vibration absorption peak of carbonate disappears after calcination using microwave, confirming the feasibility of microwave calcination for the rare earth carbonates; SEM shows that the rare earth oxides have the characteristics of better and finer particles, have better dispersion and have surface that is more loose and porous than that of products using conventional calcination; particle analysis indicates that average size (D

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