Single-Crystal SiC Resonators by Photoelectrochemical Etching

2012 ◽  
Vol 717-720 ◽  
pp. 529-532 ◽  
Author(s):  
Mohammad M. Islam ◽  
Chih Fang Huang ◽  
Feng Zhao
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Chemical Properties ◽  
Etching Technique ◽  
Scanning Method ◽  
Photoelectrochemical Etching ◽  
Resonant Structures ◽  
Single Crystal Sic ◽  
Dynamic Scanning ◽  
And Chemical Properties

In this paper, we report single-crystal 4H-SiC resonant structures fabricated by dopant-selective photoelectrochemical etching. The frequency response of the resonant beams was characterized by a dynamic scanning method using AFM with the beams excited by a piezoelectric actuator under atmosphere pressure and room temperature. The beam with a length of 35 μm shows mechanical resonance at 945 kHz. The Young’s modulus of single-crystal SiC was derived from the measured resonant frequency. Single-crystal 4H-SiC resonators developed in this study fully exploit the excellent electrical, mechanical, and chemical properties of SiC, while dopant-selective photoelectrochemical etching technique significantly simplifies the fabrication process.

Single Crystalline 4H-SiC MEMS Devices with N-P-N Epitaxial Structure

2014 ◽  
Vol 1693 ◽  
Author(s):  
Feng Zhao ◽  
Allen Lim ◽  
Zhibang Chen ◽  
Chih-Fang Huang
Keyword(s):  
Single Crystal ◽  
Electronic Devices ◽  
Device Fabrication ◽  
Flat Band ◽  
Harsh Environment ◽  
Mems Devices ◽  
Etching Technique ◽  
Epitaxial Structure ◽  
Single Crystal Sic ◽  
P Type

ABSTRACTIn this paper, single crystal 4H-SiC MEMS devices with n-p-n epitaxial structure was fabricated. A dopant-selective photoelectrochemical etching technique was applied to etch the sacrificial p-type SiC layer to release n-type SiC suspended structures on n-type SiC substrate. The selective etching was achieved by applying a bias which employs the different flat-band potentials of n-SiC and p-SiC in KOH solution. Such MEMS devices have the potential to fully exploit the superior properties of single crystal SiC for harsh environment operation, as well as mature epitaxial growth and device fabrication of 4H-SiC. The n-p-n structure, together with the previously reported p-n structure, extends the capability of monolithic integration between MEMS with electronic devices and circuits on SiC platform.

Influence of the Surfactant on the CdTe Nanomaterials Morphology

2011 ◽  
Vol 287-290 ◽  
pp. 294-297
Author(s):  
Cui Zhi Dong ◽  
Li Fang Zhang ◽  
Xiao Yan Wang ◽  
Ming Xi Zhang ◽  
Zhi Min Cui ◽  
...  
Keyword(s):  
Room Temperature ◽  
Chemical Properties ◽  
Semiconductor Materials ◽  
Alkaline Condition ◽  
Microemulsion System ◽  
X Ray ◽  
Cdte Nanoparticles ◽  
Ctab Concentration ◽  
Transmission Electron ◽  
And Chemical Properties

Because of the good photoelectric learning properties and chemical properties, CdTe nanocrystalline as an important Ⅱ-Ⅵ clan semiconductor materials has been used in LEDs, photonics, in aspects of materials and biomarker and so on. W/O microemulsion method has the peculiarity of tester simpleness, easy manipulation, room temperature react etc. In this paper CdTe nanoparticles was synthesized in CTAB/cyclohexane/isobutanol/water quatemary microemulsion system in alkaline condition and nitrogen. The morphology of the final products were characterized by X-ray power diffraction, transmission electron microscopy. according to the means, this paper researches the effect of surfactant contentration to morphology. The result is that the different morphology can be obtained through the different CTAB concentration. Finally, according to TEM chart, this paper infers the formation mechanism of the CdTe.

Physical and Chemical Properties of Silicon Dioxide Film Deposited by New Process

1987 ◽  
Vol 105 ◽  
Author(s):  
Takuji Goda ◽  
Hirotsugu Nagayama ◽  
Akihiro Hishinuma ◽  
Hideo Kawahara
Keyword(s):  
Silicon Dioxide ◽  
Room Temperature ◽  
Etching Rate ◽  
Chemical Properties ◽  
Industrial Area ◽  
Physical And Chemical Properties ◽  
Silicon Dioxide Film ◽  
Wide Range ◽  
Physical And Chemical ◽  
And Chemical Properties

AbstractA new coating process of silicon dioxide (SiO2) “LPD” process, has been developed recently. Silicon dioxide (SiO2) film can be deposited on any substrate at the room temperature by immersing in hexafluorosilicic acid (H2SiF6).In this study, physical and chemical properties of the “LPD- SiO2” film were investigated by using XPS, IR, ellipsometry, and etch rate measurement. The properties of this film deposited at the room temperature were almost the same as those of plasma CVD. The “LPD-SiO2” film without annealing was contained traces of F and OH. However, by annealing, F and OH were rapidly evaporated from the film and the film was getting densified.As the “LPD-SiO2” film deposited at the room temperature showed very good results of chemical etching rate and of step coverage, it is expected that it is possible to use this “LPD- SiO2” film in the wide range of industrial area.

scholarly journals Cocrystallization of Febuxostat with Pyridine Coformers: Crystal Structural and Physicochemical Properties Analysis

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Lei Gao ◽  
Xianrui Zhang
Keyword(s):  
Physicochemical Properties ◽  
Single Crystal ◽  
Chemical Properties ◽  
Physical And Chemical Properties ◽  
Dissolution Studies ◽  
Single Crystal Structures ◽  
Pyridine Nitrogen ◽  
Crystal Structural ◽  
Physical And Chemical ◽  
And Chemical Properties

Drug cocrystals and salts have promising applications for modulating the physicochemical properties and solubility of pharmaceuticals. In this study, a cocrystal and two salts of febuxostat (FEB) with pyridine nitrogen coformers, including 4, 4′-bipyridine (BIP), 3-aminopyridine (3AP) and 4-hydroxypyridine (4HP), were designed to improve the solubility of FEB. The single-crystal structures were elucidated, and their physical and chemical properties were investigated by IR, PXRD, and DSC. In addition, drug-related properties, including the solubility and powder dissolution rate were assessed. The solubility and powder dissolution studies showed that the FEB-BIP cocrystal and FEB-3AP salt have superior dissolution compared to FEB.

scholarly journals The Effect of Alkaline Treatment onto Physical, Thermal, Mechanical and Chemical Properties of Lemba Leaves Fibres as New Resources of Biomass

2020 ◽  
Vol 28 (4) ◽  
Author(s):  
Nur Aina Farhana Mat Nasir ◽  
Jamarosliza Jamaluddin ◽  
Zuraidah Zainudin ◽  
Mahirah Muhammad Busheri ◽  
Nadia Adrus ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Fourier Transform ◽  
Room Temperature ◽  
Functional Group ◽  
Chemical Resistance ◽  
Chemical Properties ◽  
Alkaline Treatment ◽  
Naoh Solution ◽  
Untreated Fibre ◽  
And Chemical Properties

The main purpose of this paper is to investigate the effect of alkaline treatment on the physical, thermal, mechanical and chemical properties of pristine lemba leaves fibres (LeLeFs). LeLeFs were treated with 6, 8, and 10 wt% sodium hydroxide (NaOH) solution at room temperature for 24 h. In order to determine the functional group presence after the alkaline treatment, LeLeFs were analyzed using Fourier Transform Infrared (FTIR) Spectroscopy. The density of LeLeFs treated with 10 wt% NaOH solution recorded the highest density with 1.168 g/cm³. Morphology study showed that the diameter of fibre reduced with the increment of NaOH concentration. The removal of lignin and hemicellulose could be observed in the thermogravimetric analysis (TGA). Alkaline treatment enhanced the tensile properties of fibre and 10 wt% alkaline treated fibre resulted in the highest tensile strength, modulus and elongation of the fibre at 511.10 MPa, 11.76 GPa and 3.69% respectively. Chemical resistance analysis found that the treated fibre had better chemical resistance compared to untreated fibre. Therefore, it is substantiated that alkaline treatment affects the properties of LeLeF.

Experimental Study on the Heat Transfer in the Al Powder

2009 ◽  
Vol 83-86 ◽  
pp. 953-958
Author(s):  
Ching Yen Ho ◽  
Yu Hsiang Tsai ◽  
Mao Yu Wen
Keyword(s):  
Heat Transfer ◽  
Thermal Conduction ◽  
Room Temperature ◽  
Bulk Material ◽  
Chemical Properties ◽  
Bulk Materials ◽  
Processing Technologies ◽  
Insulating Material ◽  
Physical And Chemical ◽  
And Chemical Properties

Nanometer-sized particles possess characteristic physical and chemical properties different from those of bulk materials due to an increase in surface-to-volume ratios as well as of confinement of electrons, excitons, and photons into small volumes. Therefore it is worthwhile to discuss the thermal behaviours of powders constituted by nanometer-sized particles. The heat transfer in the powder composed of nanoparticles is experimentally investigated in this paper. The understanding for thermal properties of the powder is advantageous to the advancement of the processing technologies such as laser cladding, laser sintering, powder metallurgy and its other applications. The powder is wrapped up in the slender tube made of insulating material. One end of the slender tube filled with powder is maintained at temperature 0°C and the other end is kept at room temperature. The temperature histories at two different locations in the slender tube are recorded using thermal couples. The results show that the thermal diffusivity in the powder composed of nanoparticles is larger than that in bulk material. The pressure on the Al powders enhances the rate of heat transport due to the increase of contact area for thermal conduction.

Bulrush-Like Double Perovskite: Synthesis, Tunneling Magnetoresistance, and Magnetocaloric Effects

2008 ◽  
Vol 8 (6) ◽  
pp. 2793-2810 ◽  
Author(s):  
W. Zhong ◽  
N. J. Tang ◽  
C. T. Au ◽  
Y. W. Du
Keyword(s):  
Room Temperature ◽  
Recent Observation ◽  
Chemical Properties ◽  
Double Perovskite ◽  
Tunneling Magnetoresistance ◽  
Double Perovskites ◽  
New Approach ◽  
Half Metallic ◽  
Physical And Chemical ◽  
And Chemical Properties

The recent observation of room temperature tunneling magnetoresistance (TMR) in half-metallic A2FeMoO6 (A = Ca, Sr, Ba) double perovskites, and their importance to the emerging field of spintronics has led to considerable effort being dedicated to detailed investigations of the physical and chemical properties of these materials. This article will present an review of our recent investigations covering the synthesis, structures, magnetic and transport properties of "bulrush-like" A2FeMoO6 (A = Sr, Ba). Utilizing the high shape anisotropy as well as the reactivity of A2FeMoO6 to water and a sonochemical technique, we managed to manipulate the properties of grain boundary barriers, and thus put forward a new approach for the enhancement of room temperature TMR. The magnetocaloric effects of A2FeMoO6 double perovskites will also be discussed.

Über Erdalkalimetall-Oxocuprate. VI.

1972 ◽  
Vol 27 (3) ◽  
pp. 296-301 ◽  
Author(s):  
Chr. L. Teske ◽  
Hk. Müller-Buschbaum
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Structure Determination ◽  
Chemical Properties ◽  
Crystal Structure Determination ◽  
Structural Element ◽  
X Ray ◽  
And Chemical Properties ◽  
The Way

The preparation and chemical properties of barium-oxocuprat (I) inclusive the results of the crystal structure determination by single crystal X-ray investigations are described. BaCu2O2 crystallizes isotypically with SrCu2O2 . (a = 5.72 and c = 10.06 Å. Spacegroup : D194h - 141/amd.) The influence of the bigger Ba2⨁-ion on the oxigenconfiguration surrounding the cations is discussed. It seems that the stretched O - Cu - O-dumbell is an invariable structural element in the oxocompounds of copper (I), which is shown by comparison of already known oxocuprates (I) . Only the way of interchainment varies evidently with stoichiometry.

Preparation of Lignopolyols by Chemical Modification of Kraft Lignin from Oil Palm Lignocellulosic Waste

2015 ◽  
Vol 1107 ◽  
pp. 137-141
Author(s):  
Abbas Hasan Faris ◽  
Afidah Abdul Rahim ◽  
Mohamad Nasir Mohamad Ibrahim
Keyword(s):  
Oil Palm ◽  
Room Temperature ◽  
Chemical Properties ◽  
Kraft Lignin ◽  
Kraft Pulping ◽  
Lignocellulosic Waste ◽  
Alkaline Conditions ◽  
Physical And Chemical ◽  
Tga And Dsc ◽  
And Chemical Properties

The main objective of this research was to describe the thermal and chemical characteristics of lignopolyols. Lignin was extracted from oil palm empty fruit bunch after kraft pulping process. Oxypropylation reaction was achieved by reacting kraft lignin with propylene oxide under alkaline conditions at room temperature. The physical and chemical properties of lignopolyols were evaluated by FTIR, NMR, GPC, TGA, and DSC. Lignopolyol exhibited higher chemical activity than kraft lignin. The polyols used as precursors in biomass-based wood adhesives preparation demonstrated promising results. Keywords: kraft lignin, lignopolyol, oxypropylation, NMR spectroscopy, DSC

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