A Si-based suspended tunnel structure with trapezoidal section by two - step etching

2021 ◽  
Author(s):  
Tieying Ma ◽  
Yipeng Wang ◽  
Jinzhu Zhou
Keyword(s):  
High Sensitivity ◽  
Wet Etching ◽  
High Yield ◽  
Etching Time ◽  
Tunnel Structure ◽  
Etching Method ◽  
Solid Foundation ◽  
Suspended Structure ◽  
Triton X ◽  
Sio2 Support

Abstract Two - step etching method is used to prepare Si-based suspended tunnel structure with trapezoidal section. In the first wet etching, surfactant Triton-X-100 is added to TMAH enchant to inhibit crystal plane characteristics. Bulk Si Rib with trapezoidal cross section is formed, with inclination of side and height being modulated by changing etching time, so as to obtain good stability. After SiO2 support layer is grown by thermal oxidation, pure 25%TMAH is used in the second wet etching to quickly lateral etch and undercut the bulk silicon under the support layer and form a suspended structure along <100> opening. Using additive-no additive two-step etching method, suspended structure with high stability and compressive strength, good insulation characteristics, high yield can be prepared. It lays a solid foundation for the development of high sensitivity photo, thermal, chemical and gas sensors.

Effect of Wet Etching Parameter on the Diameter and Length of Silicon Nanowires

2011 ◽  
Vol 483 ◽  
pp. 584-588
Author(s):  
Yang He ◽  
Cheng Yu Jiang ◽  
Heng Xu Yin ◽  
Chen Jun ◽  
Wei Zheng Yuan
Keyword(s):  
Silver Nanoparticle ◽  
Silicon Nanowires ◽  
Room Temperature ◽  
Wet Etching ◽  
Solution Temperature ◽  
Etching Time ◽  
Silicon Substrates ◽  
Etching Method

A wet etching method for preparing silicon nanowires on silicon substrates at near room temperature is presented. The effect of experiment parameter on the silver nanoparticle forming including concentration of AgNO3, immersing time and solution temperature, and the effect of etching time on the length of silicon nanowires are investigated. It is concluded that solution temperature has more impact to diameter of silicon nanowires than concentration of AgNO3 and immersing time and longer etching time may result in longer silicon nanowires.

The Effect of Catalyst on Carbon Nanotubes (CNTs) Synthesized by Catalytic Chemical Vapor Deposition (CVD) Technique

2011 ◽  
Vol 364 ◽  
pp. 232-237 ◽  
Author(s):  
S.Y. Lim ◽  
M.M. Norani
Keyword(s):  
Carbon Nanotubes ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Dry Etching ◽  
Wet Etching ◽  
Etching Time ◽  
Catalytic Chemical Vapor Deposition ◽  
Catalyst Pretreatment ◽  
Diameter Range

Catalyst plays a crucial role in determining the characteristics of carbon nanotubes (CNTs) produced by using thermal catalytic chemical vapor deposition (CVD). It is essential to investigate how the catalyst preparation affects the characteristics of CNTs because certain application demands specific size for optimum performance. This study reports the effect of the types of catalyst and the duration of the catalyst pre-treatment (wet etching time, dry etching time and ball milling) on the diameter of CNTs. The synthesized CNTs samples were characterized by scanning and transmission electron microscopy and Raman spectroscopy. Wet etching (2M hydrofluoric acid) time was varied from 1 to 2.5 hrs and the diameter range was found to be in the range of 23 to 52 nm. The diameter range for CNTs produced for 3 hrs and 5 hrs of dry etching treatment (with ammonia gas) are 38 to 51 nm and 23 to 48 nm, respectively. The diameter size of CNTs produced using Ni (14 to 25 nm) was found to be smaller than Fe (38 to 51 nm). There is a significant decrease in the diameter of CNTs by prolonging the wet etching period. Shorter and curly shaped CNTs can also be obtained by using Ni as the catalyst. Keywords: chemical vapor deposition, carbon nanotubes, catalyst pretreatment

scholarly journals Ni-Solder (Pb/Sn) Selective Wet-Etching Method in Acidic Solutions.

1999 ◽  
Vol 2 (1) ◽  
pp. 29-34
Author(s):  
Yukio KIZAKI ◽  
Kazuhito HIGUCHI ◽  
Soichi HONMA ◽  
Hiroshi YAMADA
Keyword(s):  
Wet Etching ◽  
Acidic Solutions ◽  
Etching Method

The ribosomes of Plasmodium berghei: isolation and ribosomal ribonucleic acid analysis

Parasitology ◽  
1978 ◽  
Vol 77 (3) ◽  
pp. 345-366 ◽  
Author(s):  
F. W. Miller ◽  
Judith Ilan
Keyword(s):  
Plasmodium Berghei ◽  
Ribonucleic Acid ◽  
Ribosomal Subunit ◽  
High Yield ◽  
Small Component ◽  
40S Ribosomal Subunit ◽  
Ribosomal Ribonucleic Acid ◽  
Rrna Species ◽  
Specific Degradation ◽  
Triton X

SummaryRibosomes and high molecular weight ribosomal ribonucleic acid (rRNA) from the blood stages of Plasmodium berghei parasites were studied in preparations free from host ribosome contamination. Purified malarial ribosomes were isolated in high yield from a population of ultrastructurally intact, viable parasites by hypertonic lysis with Triton X-100 and differential centrifugation. These ribosomes were shown to be derived from active polysomes and could be dissociated into subunits by puromycin–0·5 m KCl treatment. Malarial rRNA extracted from purified 40S and 60S ribosomal subunits was characterized by electrophoretic, sedimentation and base ratio analyses. Like certain other protozoa, the P. berghei 40S ribosomal subunit possessed an exceptionally large RNA species (mol. wt 0·9 × 106), while RNA isolated from the parasite's 60S subunit (mol. wt 1·5 × 106) was specifically ‘nicked’ to produce one large component (mol.wt 1·2 × 106) and one small component (mol.wt 0·3 × 106) in equimolar quantities. These rRNA's migrate identically on polyacrylamide gels after heating to 63°C for 5 mm or under denaturing conditions in the presence of formamide, indicating an absence of aggregation and non-specific degradation of the rRNA species. Base composition studies showed P. berghei rRNA to be low in guanosine and cytosine content, as is the case for protozoa generally.

Fabrication of Superhydrophobic Aluminum Surfaces Using Modified Nanoparticles and Ionizable Surfactants

2021 ◽  
pp. 2150035
Author(s):  
Bahram Abedi Ravan ◽  
Akbar Cheraghi
Keyword(s):  
Annealing Temperature ◽  
Mechanical Stability ◽  
Sea Water ◽  
Industrial Applications ◽  
Wet Etching ◽  
Etching Time ◽  
Water Contact ◽  
Solvent Type ◽  
Mechanical Durability ◽  
Aluminum Surfaces

In this study, plates of aluminum are made superhydrophobic via wet etching followed by deposition of nanostructure and microstructure. Etched surfaces are coated with modified nanoalumina using an ionizable surfactant. Key parameters governing the hydrophobicity such as type of the etching solvent, type of the surfactant, etching time, nanoparticle size distribution, surfactant concentration and annealing temperature are investigated. Infrared spectroscopy (IR), dynamic light scattering (DLS), scanning electron microscopy (SEM) and water contact angle (WCA) measurements are used to characterize the treated surfaces. A WCA greater than 150∘ is obtained and in order to estimate the efficiency and mechanical durability of the coatings the samples are tested in emulated sea-water. Water jet tests prove the mechanical stability of the samples. Our fabrication method results in good hydrophobicity and self-cleaning behavior of the Al surface and the obtained results may be useful for industrial applications.

Low-Cost Wet-Etching Method to Fabricate a Robust THz Tri-Layer Polarizer With a High Extinction Ratio

2021 ◽  
Author(s):  
Zhe Huang ◽  
Hau Ping Chan ◽  
Emma Pickwell-MacPherson ◽  
Edward P. J. Parrott
Keyword(s):  
Low Cost ◽  
Extinction Ratio ◽  
Wet Etching ◽  
High Extinction Ratio ◽  
Etching Method

The improvement of lipase secretion and stability by addition of inert compounds into Acinetobacter calcoaceticus cultures

2002 ◽  
Vol 48 (12) ◽  
pp. 1056-1061 ◽  
Author(s):  
Daniela A Martinez ◽  
B Clara Nudel
Keyword(s):  
Enzyme Activity ◽  
Gum Arabic ◽  
Acinetobacter Calcoaceticus ◽  
Glass Beads ◽  
High Yield ◽  
Poly Ethylene Glycol ◽  
Poly Ethylene ◽  
Cell Fractions ◽  
Triton X ◽  
Effective Additive

Acinetobacter calcoaceticus BD413 produces variable amounts of an exocellular lipase that becomes rapidly inactivated upon secretion. To achieve high yield and protect the enzyme, we assayed the addition of several inert compounds to cell-free supernatants, cell fractions, and whole cultures. Glass beads, poly(ethylene glycol) 600, Triton X-100, saccharose, gum arabic, and β-cyclodextrin were among the compounds tested. β-Cyclodextrin and gum arabic (and saccharose to a lesser extent) were effective enzyme stabilizers in cell-free supernatants, while gum arabic, glass beads, and Triton X-100 improved lipase secretion from cells, and, therefore, total lipase yield (30–50%, according to the additive). In whole cultures, β-cyclodextrin was the most effective additive, particularly in combination with glass beads or gum arabic. Indeed, cultures containing β-cyclodextrin plus gum arabic were able to maintain 95% (±1.5%) of the initial lipase activity for more than 16 h, while control cultures with no additives maintained only 10% (±4%) of the enzyme activity after the same period. In conclusion, the addition of inert compounds in cultures may be considered a useful approach for achieving increased yield and lipase stabilization, amenable for downstream processing.Key words: Acinetobacter calcoaceticus, lipase, secretion, stabilization, inert additives.

Etching Method of the Fabrication Optical Tapered Fiber and its Formula

2011 ◽  
Vol 145 ◽  
pp. 520-524 ◽  
Author(s):  
Yan Tang Huang ◽  
Xiao Hua Wang ◽  
Ri Yan Bao
Keyword(s):  
High Efficiency ◽  
Low Cost ◽  
Etching Rate ◽  
Fiber Surface ◽  
Optical Power ◽  
Etching Process ◽  
Etching Time ◽  
Mathematics Model ◽  
Tapered Fiber ◽  
Etching Method

Optical tapered fiber is one of the most high efficiency evanescent wave coupler for coupling light into and out the optical microcavity. We fabricated the tapered fiber with etching method in a designed groove with HF solution. This method was low cost, readily, and controllable. An etching groove had an oval in the middle and small V-shape towards both sides. HF solution was injected into the oval groove, while the deioned water was injected into the two V-grooves. Because of the solution diffusion, the etching rate was fast in the mid and decreased gradually towards both sides,the tapered fiber was fabricated. The optical power meter was monitoring the fiber transmission during the etching process. The transmission of the tapered fiber was 98%. We proposed a mathematics model to depict the etching process, containing the relationship between the diameter of tapered fiber and the concentration of the HF solution, the etching time, humidity, temperature. We supervised the optical intensity to deduce the tapered fiber diameter. Surface morphology with AFM was detected, the roughness of the tapered fiber surface is less than 1nm. As an evanescent coupler, we used the tapered fiber to transmit 980nm pump laser to couple to Er3+doped microsphere to stimulate 1557nm laser.

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