scholarly journals Advanced In Situ I-V Measurements Used in the Study of Porous Structures Growth on Silicon

2017 ◽  
Vol 2017 ◽  
pp. 1-7 ◽  
Author(s):  
Amare Benor
Keyword(s):  
Semiconductor Materials ◽  
Porous Structures ◽  
Diffusion Limitation ◽  
Oxide Formation ◽  
P Type ◽  
Short Time ◽  
Pore Depth

The rate of oxide formation during growth of pores structures on silicon was investigated by in situ I-V measurements. The measurements were designed to get two I-V curves in a short time (total time for the two measurements was 300 seconds) taking into account the gap (in mA/cm2) for each corresponding voltage. The in situ I-V measurements were made at different pore depth/time, at the electrolyte-pore tip interface, while etching takes place based on p-type Si. The results showed increasing, decreasing, and constant I-V gap in time, for macropores, nanopores, and electropolishing regimes, respectively. This was related to the expected diffusion limitation of oxide forming (H2O) molecules reaching the electrolyte-pore tip and the anodizing current, while etching takes place. The method can be developed further and has the potential to be applied in other electrochemically etched porous semiconductor materials.

Cathodoluminescence of Catalyst Crystallites

1982 ◽  
Vol 40 ◽  
pp. 664-665
Author(s):  
E.D. Boyes ◽  
P.L. Gai ◽  
D.B. Darby ◽  
C. Warwick
Keyword(s):  
Defect Density ◽  
Chemical Properties ◽  
Operating Conditions ◽  
Semiconductor Materials ◽  
Environmental Cell ◽  
High Resolution Structure ◽  
Commercially Important ◽  
Crystallographic Defects ◽  
Resolution Structure

The extended crystallographic defects introduced into some oxide catalysts under operating conditions may be a consequence and accommodation of the changes produced by the catalytic activity, rather than always being the origin of the reactivity. Operation without such defects has been established for the commercially important tellurium molybdate system. in addition it is clear that the point defect density and the electronic structure can both have a significant influence on the chemical properties and hence on the effectiveness (activity and selectivity) of the material as a catalyst. SEM/probe techniques more commonly applied to semiconductor materials, have been investigated to supplement the information obtained from in-situ environmental cell HVEM, ultra-high resolution structure imaging and more conventional AEM and EPMA chemical microanalysis.

NbC and VC Nanoparticles Reinforced Fe-Si-Mn Matrix Composite In Situ Synthesized by Plasma Jet

2011 ◽  
Vol 415-417 ◽  
pp. 71-75
Author(s):  
Chun Xiang Cui ◽  
Yan Chun Li ◽  
Tie Bao Wang ◽  
Shuang Jin Liu ◽  
Suek Bong Kang
Keyword(s):  
Matrix Composite ◽  
Hybrid Composite ◽  
Gas Flow ◽  
Plasma Jet ◽  
Homogeneous Distribution ◽  
Active Nitrogen ◽  
Ceramic Particles ◽  
Nanometer Range ◽  
Short Time

In situ NbC and VC nanoparticles reinforced Fe-Si-Mn-Nb-V matrix composite was carried out using a plasma jet with a plasma gas flow of (Ar + CH4) for very short time. The process involve improving the efficiency of the reaction in terms of consumption of the available active nitrogen atoms as well as the production of very fine and homogeneous distribution of all reinforcing phases of ceramic particles, preferable in the nanometer range. The nanoreinforcements synthesized by in situ reaction in this hybrid composite are NbC and VC ceramic particles.

Study on Phases and Thermoelectric Properties of Bulk Fe4Sb12 and Fe3CoSb12 Prepared by Milling and Sintering

2011 ◽  
Vol 121-126 ◽  
pp. 1526-1529
Author(s):  
Ke Gao Liu ◽  
Jing Li
Keyword(s):  
Thermoelectric Properties ◽  
Impurity Phase ◽  
Semiconductor Materials ◽  
Thermal Constant ◽  
X Ray Diffraction ◽  
X Ray ◽  
Seebeck Coefficients ◽  
Maximum Value ◽  
Type Semiconductor ◽  
P Type

Bulk Fe4Sb12 and Fe3CoSb12 were prepared by sintering at 600 °C. The phases of samples were analyzed by X-ray diffraction and their thermoelectric properties were tested by electric constant instrument and laser thermal constant instrument. Experimental results show that, the major phases of bulk samples are skutterudite with impurity phase FeSb2. The electric resistivities of the samples increase with temperature rising at 100~500 °C. The bulk samples are P-type semiconductor materials. The Seebeck coefficients of the bulk Fe4Sb12 are higher than those of bulk Fe3CoSb12 samples at 100~200 °C but lower at 300~500 °C. The power factor of the bulk Fe4Sb12 samples decreases with temperature rising while that of bulk Fe3CoSb12 samples increases with temperature rising at 100~500 °C. The thermal conductivities of the bulk Fe4Sb12 samples are relatively higher than those of and Fe3CoSb12, which maximum value is up to 0.0974 Wm-1K-1. The ZT value of bulk Fe3CoSb12 increases with temperature rising at 100~500 °C, the maximum value is up to 0.031.The ZT values of the bulk Fe4Sb12 samples are higher than those of bulk Fe3CoSb12 at 100~300 °C while lower at 400~500 °C.

Low-Temperature LPCVD MEMS Technologies

2002 ◽  
Vol 729 ◽  
Author(s):  
Roger T. Howe ◽  
Tsu-Jae King
Keyword(s):  
Silicon Germanium ◽  
Polycrystalline Silicon ◽  
Rf Mems ◽  
Sige Layer ◽  
Copper Metallization ◽  
Si Films ◽  
P Type ◽  
Mems Process ◽  
Post Deposition

AbstractThis paper describes recent research on LPCVD processes for the fabrication of high-quality micro-mechanical structures on foundry CMOS wafers. In order to avoid damaging CMOS electronics with either aluminum or copper metallization, the MEMS process temperatures should be limited to a maximum of 450°C. This constraint rules out the conventional polycrystalline silicon (poly-Si) as a candidate structural material for post-CMOS integrated MEMS. Polycrystalline silicon-germanium (poly-SiGe) alloys are attractive for modular integration of MEMS with electronics, because they can be deposited at much lower temperatures than poly-Si films, yet have excellent mechanical properties. In particular, in-situ doped p-type poly-SiGe films deposit rapidly at low temperatures and have adequate conductivity without post-deposition annealing. Poly-Ge can be etched very selectively to Si, SiGe, SiO2 and Si3N4 in a heated hydrogen peroxide solution, and can therefore be used as a sacrificial material to eliminate the need to protect the CMOS electronics during the MEMS-release etch. Low-resistance contact between a structural poly-SiGe layer and an underlying CMOS metal interconnect can be accomplished by deposition of the SiGe onto a typical barrier metal exposed in contact windows. We conclude with directions for further research to develop poly-SiGe technology for integrated inertial, optical, and RF MEMS applications.

Development of densification-resistant castable porous structures from in situ mullite

2015 ◽  
Vol 41 (8) ◽  
pp. 9443-9454 ◽  
Author(s):  
Lucíola L. Sousa ◽  
Adriane D.V. Souza ◽  
Leandro Fernandes ◽  
Vera L. Arantes ◽  
Rafael Salomão
Keyword(s):  
Porous Structures

scholarly journals The evolution of the metazoan Toll receptor family and its expression during protostome development

2021 ◽  
Author(s):  
Andrea Orús-Alcalde ◽  
Tsai-Ming Lu ◽  
Andreas Hejnol
Keyword(s):  
Phylogenetic Analysis ◽  
Transmembrane Domain ◽  
Leucine Rich Repeat ◽  
Animal Development ◽  
Phylogenetic Studies ◽  
Repeat Domain ◽  
Toll Receptor ◽  
P Type

Abstract Background: Toll-like receptors (TLRs) play a crucial role in immunity and development. They contain leucine-rich repeat domains, one transmembrane domain, and one Toll/IL-1 receptor domain. TLRs have been classified into V-type/scc and P-type/mcc TLRs, based on differences in the leucine-rich repeat domain region. Although TLRs are widespread in animals, detailed phylogenetic studies of this gene family are lacking. Here we aim to uncover TLR evolution by conducting a survey and a phylogenetic analysis in species across Bilateria. To discriminate between their role in development and immunity we furthermore analyzed stage-specific transcriptomes of the ecdysozoans Priapulus caudatus and Hypsibius exemplaris, and the spiralians Crassostrea gigas and Terebratalia transversa.Results: We detected a low number of TLRs in ecdysozoan species, and multiple independent radiations within the Spiralia. V-type/scc and P-type/mcc type-receptors are present in cnidarians, protostomes and deuterostomes, and therefore they emerged early in TLR evolution, followed by a loss in xenacoelomorphs. Our phylogenetic analysis shows that TLRs cluster into three major clades: clade α is present in cnidarians, ecdysozoans, and spiralians; clade β in deuterostomes, ecdysozoans, and spiralians; and clade γ is only found in spiralians. Our stage-specific transcriptome and in situ hybridization analyses show that TLRs are expressed during development in all species analyzed, which indicates a broad role of TLRs during animal development.Conclusions: Our findings suggest that the bilaterian TLRs likely emerged by duplication from a single TLR encoding gene (proto-TLR) present in the last common cnidarian-bilaterian ancestor. This proto-TLR gene duplicated before the split of protostomes and deuterostomes; a second duplication occurred in the lineage to the Trochozoa. While all three clades further radiated in several spiralian lineages, specific TLRs clades have been presumably lost in others. Furthermore, the expression of the majority of these genes during protostome ontogeny suggests their involvement in immunity and development.

Research on Performance of Polyimide In Situ Modification Anionic Polymerization Nylon 6

2014 ◽  
Vol 1052 ◽  
pp. 242-248
Author(s):  
Hong Kai Zhao ◽  
Hong Li Wang
Keyword(s):  
Bisphenol A ◽  
Water Absorption ◽  
In Situ Polymerization ◽  
Microscopic Analysis ◽  
Nylon 6 ◽  
Grafting Reaction ◽  
Lamellar Crystals ◽  
End Capping ◽  
Short Time

Through the polymerization and grafting reaction of bisphenol A dianhydride and bisphenol A diamine, the polyimide activator (PI activator) of acyl caprolactam end capping is obtained and then the anionic in-situ polymerization modified nylon 6 resin is obtained. Viscosity analysis shows that PI consumption is higher than 0.1 (of monomer mass), the reaction temperature is higher than 160°C, the viscosity rises rapidly in a short time and the rapid polymerization molding can be realized; when PI consumption is higher than 0.15 (of monomer mass), the water absorption of matrix resin will be lower than 1.4%; compared with the nylon resin, its water absorption is significantly lowered and its mechanical property is improved greatly; microscopic analysis shows that PI molecules fail to enter the crystalline phase of the nylon 6 and form lamellar crystals in the nylon matrix, which plays a role of enhancement and obstruction; differential thermal analysis shows that PI reduces the melting enthalpy and melting point temperature of nylon 6 resin, which indicates that PI reduces the crystallization capacity of nylon 6.

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