Growth of InGaN Films by MBE at the Growth Temperature of GaN

1995 ◽  
Vol 395 ◽  
Author(s):  
R. Singh ◽  
T.D. Moustakas
Keyword(s):  
Phase Separation ◽  
Spinodal Decomposition ◽  
Growth Temperature ◽  
Composition Range ◽  
The Other ◽  
Entire Composition Range ◽  
Other Hand ◽  
Ingan Alloys

ABSTRACTWe report the growth of InGaN alloys over practically the entire composition range at the growth temperature of GaN (700–800 °C) by MBE. We found that when the grown films are thick (> 0.3 μm), incorporation of more than about 30% indium results in phase separation of InN, which is consistent with spinodal decomposition. On the other hand we discovered that such phase separation is absent in thin InGaN films ( < 600Å) grown as GaN/InGaN/GaN heterostructures. In such configurations we were able to incorporate up to 81% In, which is the highest yet reported.

Solution Growth of 3C-SiC on 6H-SiC Using Si Solvent under N2-He Atmosphere

2008 ◽  
Vol 600-603 ◽  
pp. 187-190 ◽  
Author(s):  
Kazuhiko Kusunoki ◽  
Kazuhito Kamei ◽  
Nobuyoshi Yashiro ◽  
Takashi Tanaka ◽  
Akihiro Yauchi
Keyword(s):  
Growth Temperature ◽  
The Other ◽  
Solution Growth ◽  
Epitaxial Layers ◽  
Other Hand ◽  
Homoepitaxial Layers ◽  
Top Seeded Solution Growth ◽  
Koh Etching

Top seeded solution growth of SiC on on-axis 6H-SiC was performed using Si solvent at growth temperature as high as 1645-1870°C. It was found that different polytypes of SiC layers were grown on 6H-SiC depending on gas species during growth. The growth under He atmosphere produced 6H-SiC homoepitaxial layers. On the other hand, the growth under N2-He atmosphere led to 3C-SiC epitaxial layers. It was obvious that the nitrogen dissolved in solvent strongly favoured the 3C-SiC polytype formation on 6H-SiC. We also conducted characterization of 3C-SiC layers grown on 6H-SiC (0001)Si by TEM, molten KOH etching and precise XRD measurement.

Non-Stoichiometric Transfer of Complex Oxides by Pulsed Laser Deposition at Low Fluences

1995 ◽  
Vol 397 ◽  
Author(s):  
B. Dam ◽  
J.H. Rector ◽  
J. Johansson ◽  
DG. DE Groot ◽  
R. Griessen
Keyword(s):  
Phase Separation ◽  
Pulsed Laser Deposition ◽  
Volume Diffusion ◽  
Pulsed Laser ◽  
Target Surface ◽  
Complex Oxides ◽  
The Other ◽  
Laser Deposition ◽  
Other Hand

ABSTRACTWe provide evidence that non-stoichiometric ablation of YBa2Cu3O7δ at low fluences is due to a phase separation of the target surface. On the other hand, in SrTiO3 we find at low fluences evidence for preferential ablation which is assisted by volume-diffusion. As a result, the Sr/Ti ratio of the ablated films can be tuned by choosing the appropriate fluence.

Initial Phase Formation and Distribution in the Pt-GexSi1−x and Cr-GexSi1−x Systems

1990 ◽  
Vol 181 ◽  
Author(s):  
Q. Z. Hong ◽  
J. W. Mayer
Keyword(s):  
Phase Separation ◽  
Phase Formation ◽  
Initial Phase ◽  
The Other ◽  
Other Hand

ABSTRACTMetal-GeSi reactions have been investigated in the Pt-GeSi and Cr-GeSi systems. Pt started to diffuse into and react with the alloys at 250 °C. The reacted region consisted of a uniform mixture of Pt2Si and Pt2Ge, with the same ratios of Ge to Si as those in the unreacted region. On the other hand, the Cr-GeSi reaction was induced by Ge motion at 375 °C. As a result a two-layer phase separation was observed. A Si-rich ternary layer was sandwiched between a germanide layer and the unreacted alloy

scholarly journals Investigation on the Microstructure, Texture and Magnetostriction of Directionally Solidified Tb0.3Dy0.7Fe1.95−xVx Alloys

2012 ◽  
Vol 2012 ◽  
pp. 1-6
Author(s):  
J. Arout Chelvane ◽  
Mithun Palit ◽  
Himalay Basumatary ◽  
S. Banumathy ◽  
A. K. Singh ◽  
...  
Keyword(s):  
Spinodal Decomposition ◽  
Primary Phase ◽  
Small Addition ◽  
Matrix Phase ◽  
The Other ◽  
Directionally Solidified ◽  
Rich Phase ◽  
Other Hand ◽  
Transformation Texture ◽  
The Matrix

Effect of V addition on the microstructure and magnetostriction of directionally solidified Tb0.3Dy0.7Fe1.95 has been investigated. The microstructure of V added alloys (Tb0.3Dy0.7Fe1.95−xVx with x=0, 0.025, 0.05, and 0.075) indicate that Fe-50 at.% V is formed as primary phase, which subsequently undergoes spinodal decomposition. The spinodially decomposed Fe-rich phase reacts with the liquid and forms the matrix phase, (Tb,Dy)Fe2. The V-rich spinodally decomposed product, on the other hand, exists as remnant phase without undergoing any metallurgical transformation. Texture studies indicate that the grains of (Tb,Dy)Fe2 show 〈110〉/rotated 〈110〉 and 〈112〉 orientations for all compositions investigated in the directionally solidified condition. An improvement in magnetostriction has been noticed for small addition of V (x=0.025) and with further addition the magnetostrictive property decreases. The formation of additional phases containing vanadium is attributed to be the reason when V is added in higher concentration (x>0.025) levels.

Phase Separation in Sol-Gel Systems of Organic-Inorganic Hybrids

2006 ◽  
Vol 45 ◽  
pp. 759-768
Author(s):  
Kazuki Nakanishi ◽  
Kazuyoshi Kanamori
Keyword(s):  
Phase Separation ◽  
Hybrid Materials ◽  
Sol Gel ◽  
Surface Hydrophobicity ◽  
The Other ◽  
Inorganic Hybrid ◽  
Surface Hydrophilicity ◽  
Other Hand ◽  
Sol Gel Process ◽  
Polymerization Induced Phase Separation

Organic-inorganic hybrid monoliths with well-defined macropores and/or mesopores have been synthesized by a sol-gel process accompanied by polymerization-induced phase separation. Using aklyltrialkoxysilanes and alkylene-bridged alkoxysilanes, two different categories of organo-siloxane networks have been characterized in view of macroporoisity based on phase separation as well as mesoporosity based on supramolecular templating by surfactants. The alkyl-terminated polysiloxane network exhibited substantial surface hydrophobicity together with the mechanical flexibility. On the other hand, the alkylene-bridged network behaved much more similarly to those prepared from tetraalkoxysilanes with regard to surface hydrophilicity, mechanical rigidness and mesopore-forming ability. Supramolecular templating of mesopores embedded in the gel skeletons comprising well-defined macroporous network has proven to give wide variety of hierarchically designed macro-mesoporous organic-inorganic hybrid materials.

Fracture Toughness and Hardness of Ti(C0.7N0.3)-19Mo2C-xNbC-24Ni

2015 ◽  
Vol 1088 ◽  
pp. 255-259 ◽  
Author(s):  
Hiroyuki Hosokawa ◽  
Kiyotaka Katou ◽  
Koji Shimojima ◽  
Ryoichi Furushima ◽  
Akihiro Matsumoto
Keyword(s):  
Fracture Toughness ◽  
Phase Separation ◽  
The Other ◽  
Binder Phase ◽  
Hard Phase ◽  
Other Hand

The fracture toughness and hardness of Ti (C0.7N0.3)-19Mo2C-xNbC-24Ni cermets (x= 0, 5, 20) were studied. Fracture toughness of 5 NbC was the largest, and it of 20 NbC was the lowest. The microstructures of all the cermets consisted of Ti (C,N) and solid soluted Ti (C,N) hard phase, and Ni binder phase. The solid soluted Ti (C,N) surrounded Ti (C,N), namely, core-rim structures were observed in 0NbC and 5NbC. On the other hand, the isolated Ti (C,N) and solid soluted Ti (C,N) were observed in 20NbC, as a result of the phase separation between Ti (C,N) core and solid soluted Ti (C,N).

Crystallization of undercooled liquid spinodals: Part II

1999 ◽  
Vol 14 (9) ◽  
pp. 3663-3667 ◽  
Author(s):  
K. L. Lee ◽  
H. W. Kui
Keyword(s):  
Phase Separation ◽  
Latent Heat ◽  
Spinodal Decomposition ◽  
Liquid State ◽  
Morphological Changes ◽  
Microstructural Analysis ◽  
The Other ◽  
Undercooled Liquid ◽  
Metastable Liquid ◽  
Undercooled Melt

We demonstrated in “Phase separation in undercooled molten Pd80Si20: Part I” that when a molten Pd80Si20 ingot is undercooled into its undercooling regimen with ΔT ≥ 220 K (ΔT = T1 – T, where T1 is the liquidus and T is the temperature of the undercooled melt), liquid-state phase separation by spinodal decomposition occurs. On crystallization, one of the metastable liquid spinodals becomes Pd3Si, whereas the other one turns into Pd9Si2. In both cases, Pd particles precipitate out. Microstructural analysis indicates the Pd3Si subnetwork forms first. It then acts as a seed for the subsequent crystallization of the remaining undercooled melt, which finally forms the Pd9Si2 dendrites. As crystallization proceeds, latent heat and volume contraction bring about morphological changes.

A study of cometary eruptions through OH radio-lines

1999 ◽  
Vol 173 ◽  
pp. 249-254
Author(s):  
A.M. Silva ◽  
R.D. Miró
Keyword(s):  
Short Duration ◽  
Growth Curves ◽  
The Other ◽  
Initial Mass ◽  
Radio Lines ◽  
Other Hand ◽  
Sudden Rise

AbstractWe have developed a model for theH2OandOHevolution in a comet outburst, assuming that together with the gas, a distribution of icy grains is ejected. With an initial mass of icy grains of 108kg released, theH2OandOHproductions are increased up to a factor two, and the growth curves change drastically in the first two days. The model is applied to eruptions detected in theOHradio monitorings and fits well with the slow variations in the flux. On the other hand, several events of short duration appear, consisting of a sudden rise ofOHflux, followed by a sudden decay on the second day. These apparent short bursts are frequently found as precursors of a more durable eruption. We suggest that both of them are part of a unique eruption, and that the sudden decay is due to collisions that de-excite theOHmaser, when it reaches the Cometopause region located at 1.35 × 105kmfrom the nucleus.

Closing the GAP—A 5Å Scanning Microscope

1969 ◽  
Vol 27 ◽  
pp. 6-7
Author(s):  
A. V. Crewe
Keyword(s):  
Normal Form ◽  
The Other ◽  
Resolving Power ◽  
Scanning Microscope ◽  
Conventional Microscope ◽  
Other Hand ◽  
Closing The Gap ◽  
Thermal Sources ◽  
Better Than ◽  
Transmission Microscope

We have become accustomed to differentiating between the scanning microscope and the conventional transmission microscope according to the resolving power which the two instruments offer. The conventional microscope is capable of a point resolution of a few angstroms and line resolutions of periodic objects of about 1Å. On the other hand, the scanning microscope, in its normal form, is not ordinarily capable of a point resolution better than 100Å. Upon examining reasons for the 100Å limitation, it becomes clear that this is based more on tradition than reason, and in particular, it is a condition imposed upon the microscope by adherence to thermal sources of electrons.

Life Beyond 1MeV

1980 ◽  
Vol 38 ◽  
pp. 30-33
Author(s):  
K.H. Westmacott
Keyword(s):  
Electron Microscopy ◽  
Past Experience ◽  
The Other ◽  
Good Case ◽  
Other Hand ◽  
The U.S

Life beyond 1MeV – like life after 40 – is not too different unless one takes advantage of past experience and is receptive to new opportunities. At first glance, the returns on performing electron microscopy at voltages greater than 1MeV diminish rather rapidly as the curves which describe the well-known advantages of HVEM often tend towards saturation. However, in a country with a significant HVEM capability, a good case can be made for investing in instruments with a range of maximum accelerating voltages. In this regard, the 1.5MeV KRATOS HVEM being installed in Berkeley will complement the other 650KeV, 1MeV, and 1.2MeV instruments currently operating in the U.S. One other consideration suggests that 1.5MeV is an optimum voltage machine – Its additional advantages may be purchased for not much more than a 1MeV instrument. On the other hand, the 3MeV HVEM's which seem to be operated at 2MeV maximum, are much more expensive.

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