Effect Of Chemical Etching Research Articles

Model analysis of the feature profile evolution during Si etching in HBr-containing plasmas

Feature profiles of Si etched in HBr-containing plasmas have been analyzed through a comparison between experiments and simulations. The emphasis was placed on a mechanistic understanding of the difference in the evolution of profile anomalies (such as tapering, footing, and microtrenching) during Si etching between HBr- and Cl2-based plasmas. Experiments were made with Cl2/O2/HBr chemistry by varying the HBr mixing ratio, using a commercial ultrahigh-frequency electron cyclotron resonance plasma etching reactor, where HCl/O2 chemistry was also employed to compare with that of Cl2/O2 and HBr/O2. Numerical simulations of feature profile evolution were made using a semiempirical atomic-scale cellular model based on the Monte Carlo method that we developed for Si etching in Br2, HBr, and Cl2 plasmas, where surface chemistry and kinetics include the effects of ion reflection from and/or penetration into feature surfaces on incidence. The experiments showed more vertical sidewalls with less footing and microtrenching with HBr; concretely, with increasing HBr mixing ratio in Cl2/O2/HBr plasmas, the tapering is reduced and minimized at 80% HBr where slight lateral or side etching tends to occur, the footing is reduced gradually, and the microtrenching fades away at more than 20% HBr. A comparison with simulations, with the help of separate analyses of ion reflection from surfaces on incidence, indicated that the smaller reflection probability and reflected energy fraction of Br+ on tapered sidewalls (compared to Cl+) are responsible for reduced tapering, footing, and microtrenching in HBr-containing plasmas; moreover, chemical etching effects of neutral H atoms at the feature bottom and sidewalls, arising from the larger reaction probability of H (compared to Cl), are also responsible for reduced microtrenching and for reduced tapering (and the lateral or side etching induced) therein.

The Effects of Chemical Etching and Ultra-Fine Grain Structure of Titanium on MG-63 Cells Response

In this work, we study the influence of the surface properties of ultrafine grained (UFG) and coarse grained (CG) titanium on the morphology, viability, proliferation and differentiation of osteoblast-like MG-63 cells. Wet chemical etching in H2SO4/H2O2 and NH4OH/H2O2 solutions was used for producing surfaces with varying morphology, topography, composition and wettability. The topography and morphology have been studied by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The composition was determined by time of flight mass-spectrometry (TOF-SIMS) and X-ray photoelectron spectroscopy (XPS). The results showed that it is possible to obtain samples with different compositions, hydrophilicity, topography and nanoscale or/and microscale structures by changing the etching time and the type of etching solution. It was found that developed topography and morphology can improve spreading and proliferation rate of MG-63 cells. A significant advantage of the samples of the UFG series in comparison with CG in adhesion, proliferation at later stages of cultivation (7 days), higher alkaline phosphatase (ALP) activity and faster achievement of its maximum values was found. However, there is no clear benefit of the UFG series on osteopontin (OPN) expression. All studied samples showed no cytotoxicity towards MG-63 cells and promoted their osteogenic differentiation.

Enhancement of both optical and catalytic activity of copper-decorated porous silicon micro-particles

To the best of our knowledge, this study is the first to investigate the effect of chemical vapour etching (CVE) combined with copper decoration on both the optical and catalytic activities of silicon micro-particles (SiμPs). After exposure to acid vapours emanating from a hot solution of hydrogen fluoride/nitric acid (HF/HNO3), scanning electron microscope images of the treated powder show the formation of a porous, sponge-like structure on the sidewalls of SiμPs. Fourier transmission infra-red analysis shows the appearance of hydride bonds related to the formation of the porous structure. X-ray diffraction measurements and Raman spectroscopy show the good crystallinity of the samples. The strong photoluminescence properties of the obtained porous SiμPs (pSiμPs) reveal that the vapour etching process generated silicon nanocrystals within these particles. In this work, we have investigated the catalytic activity of copper nanoparticles (CuNPs) loaded on the surface of pSiμPs, in order to reduce the toxic compound 4-nitrophenol to 4-aminophenol. The results show excellent catalytic performance in very short times (less than 1 min).

Effect of Different Gamma Dose and Chemical Etching on Pre- and Post-Alpha-Irradiated PM-355 Polymer

This work is based on the effect of different gamma doses with pre- and post-alpha-irradiated PM-355 polymer (polycarbonate of allyl diglycol). The phase crystallinity and structural analysis of the reference and irradiated PM-355 polymer were analyzed using an X-ray diffraction (XRD) study. It is revealed that the irradiation and etching reduce the %crystallinity but increase the crystallite size of the PM-355 polymer. The increase in crystallite size of PM-355 polymer after irradiation is supported by the scanning electron microscopic (SEM) analysis. The etching of the samples results in an increase in its track diameter. The optical band gap energy, measured by ultraviolet-visible (UV-VIS) spectroscopy, shows a decrement trend with the increase of gamma and alpha irradiation doses, and etching for all sets of samples under investigation. The number of carbon atoms per conjugation and per cluster has increased after gamma irradiation and etching. However, the increment is more pronounced for etched samples compared to nonetched ones. This indicates that etching results in a bigger size of cluster. Photoluminescence (PL) for both cases before and after etching has a dominant peak around 430 nm before and after irradiation, and change in peak intensity after irradiation confirmed that particle bombardment induced defects and clusters in the PM-355, which serves as nonradiative centers. The polymer can be used as a detector for gamma irradiation.

Effect of Dynamic Chemical Etching on the Pore Structure, Permeability, and Mechanical Properties of Ti-Nb-Zr Scaffolds for Medical Applications

Abstract Improving the post-processing of metallic porous tissue scaffolds is an essential step to create a new generation of superelastic implants for the replacement of damaged bone tissue. In this study, the dynamic chemical etching technique is applied to improve the permeability and to optimize the porous structure of Ti-Nb-Zr scaffolds fabricated by the powder metallurgy-based space holder technique. The etched scaffolds are characterized in terms of their porous structure geometry, permeability, and mechanical properties. It is shown that an increase in porosity from 49% to 54% during the etching is mainly due to an increase in the number of 100 to 800 μm-diameter pores, from 30% to 50% of them measuring from 100 to 300 μm in size. These changes in the porous structure lead to a significant increase of its permeability, i.e., from (0.1–15) × 10−11 m2 before etching to (44–91) × 10−11 m2, after etching; these permeability ranges corresponding to those of bone tissues. Furthermore, the etched scaffolds show systematically higher yield compressive stresses as compared to the as-sintered scaffolds of equivalent porosities. Finally, the highly permeable etched Ti-Nb-Zr scaffolds with a porosity varying from 40% to 60% exhibit an apparent Young’s modulus ranging from 8.6 to 1.9 GPa and an ultimate compressive strength from 650 to 190 MPa, which can be considered as a promising balance of properties for the potential use of these scaffolds as bone implants.

Carrageenan Assisted Synthesis of Morphological Diversity of CdO and Cd (OH)2 with High Antibacterial Activity

This research reports a simple method for the controlled synthesis of cadmium oxide (CdO) and cadmium hydroxide (Cd(OH) 2 ) with different morphology in the presence of NaBH 4 or LiBH 4 as reducing agent, by using k-carrageenan as a capping agent and potassium bromide as a template. The synthesized products were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The impacts of reducing agent, reaction atmosphere and concentration of reducing agent on size and morphology of the particles were discussed. We suggested that chemical etching and Kirkendall effect play a key role on morphology of particles, and the etch rate depends on reducing agent concentration. It was found that by increasing the concentration of reducing agent the intensified etching lead to an increase in the size of the particles. The results show an increase in particle size with decreasing reducing agents power. The various morphologies obtained for CdO and Cd(OH) 2 such as hollow cube, macro rod, nanoplate and macroplate were discussed based on the Kirkendall effect and chemical etching. Finally, the antibacterial activity was screened against Escherichia coli and Staphylococcus aureus . The inhibition zones were ranged from 36-47 mm and 25-47 mm for different morphologies of CdO and Cd(OH) 2 respectively.

Effect of PVP content on photocatalytic properties of CuSbS2 particles with chemical etching

In the paper, the effects of polyvinylpyrrolidone (PVP) concentration and chemical wet etching on morphologies and phase composition of CuSbS2 particles synthesized by microwave irradiation method were investigated. The phase structure, morphologies, and optical and photocatalytic properties were analyzed by using characterization techniques. The results showed that the morphology of as-prepared particles was spherical and the shape of particles etched in Na2S solution was tetragonal rod-like structure. The optical band gap of the particles with 1.5 g PVP after chemical etching was about 1.41 eV. The photocatalytic performance of CuSbS2 could be significantly improved after Na2S chemical etching. The amounts of PVP had an obvious influence on specific surface area of as-synthesized CuSbS2 particles. The CuSbS2 particles with 1.5 g PVP had the best photocatalytic performance after chemical etching treatment, and the C/C0 value reached 0.36.

ИЗУЧЕНИЕ СТРУКТУРЫ И ОПТИЧЕСКОЙ ПЛОТНОСТИ ПОЛИИМИДНЫХ ТРЕКОВЫХ (ЯДЕРНЫХ) МЕМБРАН

The paper presents the results of a study of the surface and optical properties of the PM-1 polyimide film and the polyimide track membrane. For the study, polyimide (track) nuclear membranes manufactured by ION TRACK TECHNOLOGY FOR INNOVATIVE PRODUCT (it4ip, Belgium)) is used. The pore diameter is 200 nm, the pore density is 5 • 108 cm-1, and the thickness of the polyimide membrane is 25 μm. The data of IR spectroscopy are presented. It is shown that the decrease in the intensity of the peaks of the IR spectra of the membrane compared to the film is a consequence of the oxidative degradation of the polyimide after exposure to heavy ions and chemical etching. The data on the effects of heavy ion irradiation and chemical etching of a polyimide film to obtain a membrane on surface hydrophobicity / hydrophilicity are presented. The optical density of the film and track membranes is determined in the wavelength range of 350-950 nm. The optical density is measured in increments of 50 nm. It is shown that despite the strong difference in the spectral dependence of the optical density of the polyimide film and the track membrane, the optical density of the PM-1 film and the track membrane is quite low in the entire studied wavelength range and does not exceed 0.26 and 0.42, respectively.

Phytic acid functionalized ZIF-67 decorated graphene nanosheets with remarkably boosted electrochemical sensing performance

Recently, metal-organic frameworks (MOFs) display great application potential in the field of electrochemical catalysis and sensing due to its extraordinary properties. Herein, Co-based MOFs (ZIF-67) decorated graphene nanosheets (GS) heterogeneous hybrids (ZIF-67@GS) with sandwich-like morphology is first prepared by a facile in situ synthesis method. The electrochemical activity of ZIF-67 polyhedrons is effectively enhanced for the introduction of the high conductivity of graphene nanosheets. Subsequently, phytic acid functionalized ZIF-67 with unique core-shell structure decorated GS (PA-ZIF-67@GS) is prepared through the chemical etching effect of phytic acid. Surprisingly, the exposure level of metal active sites, electrochemical active surface area, electron transfer kinetic of the chemically etched ZIF-67@GS are further significantly boosted. Benefiting from the greatly modified interface property, the as-obtained PA-ZIF-67@GS hybrids exhibit excellent electrocatalytic activity toward the oxidation of glucose, and an ultrasensitive nonenzymatic electrochemical sensing platform is then developed. It is believed that this work may provide effective guidance for optimizing the electrochemical catalytic and sensing performance of other series of MOFs.

Nanosphere lithography: the effect of chemical etching and annealing sequence on the shape and spectrum of nano-metal arrays

In this paper, it is shown that the sequence of chemical etching of the template and annealing has a significant effect on the shape and spectrum of the nano-metal arrays fabricated by nanosphere lithography (NSL). Higher nanoparticles with sharp edges are fabricated as a consequence of annealing the metal coated template, which is a 2d colloidal crystal, before chemical etching. Consequently, the absorption spectra of the fabricated sample become much sharper, in comparison with the one that is fabricated with the reversed order and also a shift is observed in the peak wavelength. The achieved result has practical importance for the applications of these nano-metal arrays in localized surface plasmon resonance (LSPR) based sensors.

Strengthening bonding strength in NiTi SMA fiber-reinforced polymer composites through acid immersion and Nanosilica coating

Extensive applications of shape-memory alloy fiber-reinforced polymer composites are limited by the weak bonding conditions between alloy fibers and their surrounding matrix. In this work, we aim to investigate an effective means for elevating the interfacial bonding between nickel-titanium shape-memory alloy fibers and epoxy matrix by the combination of nitric acid immersion and nanosilica particles coating. Three experimental tests were carefully designed and conducted for verifying and validating the proposal. They include the uniaxial tensile test of chemically etched fibers, the pull-out test against a single fiber embedded inside a cylindrical epoxy matrix, and the three-point flexural test on fiber-reinforced polymer composites. Extensive parametric tests were performed in order to both qualify and quantify the effects of chemical etching, nanoparticle coating, and their combination. Experimental tests were followed a comprehensive analysis on both the mechanical behavior and the microscopic and macroscopic morphology of the specimens. Experimental results suggest the possibility of effectively elevating the interfacial bonding strength between nickel-titanium shape-memory alloy and epoxy matrix by the appropriate coupling of acid immersion and nanoparticle coating. Microscopical optimization mechanisms were also proposed and validated in terms of both intergranular and transgranular cracking along fiber/matrix interface subjected to shear loading.

Fabrication of mechanically enhanced superhydrophobic surface using nanosecond laser-based high-throughput surface nanostructuring (nHSN)

Abstract In this work, we conduct a systematic experimental investigation of surface integrity for steel and aluminum alloys processed via nanosecond laser-based high-throughput surface nanostructuring (nHSN) process. nHSN surface morphology and surface chemistry are first experimentally characterized, and the results show that surface nanostructure with proper surface chemistry is generated due to the combined effect of chemical etching and attachment of functional groups of low surface energy. Desired surface wetting behavior is achieved using a proper silane reagent during the nHSN chemical immersion treatment phase, while surface nanostructure can be finely modulated by adjusting the laser processing parameters. nHSN nanostructures with fluorosilane chemistry exhibit strong capability to repel water, leading to superhydrophobicity achieved on two important engineering metal alloys, namely steel and aluminium alloys. It is further experimentally demonstrated that the microhardness and anti-corrosion performance of the nHSN surface can be significantly enhanced compared with the untreated surface, indicating that the nHSN process is very effective for enhancing the mechanical strength and corrosion resistance of these important metal alloys. These results show that nHSN simultaneously creates random nanostructures, attains desirable surface chemistry and enhances surface integrity over large-area metal alloy surfaces.

Nanosecond laser-based high-throughput surface nanostructuring (nHSN)

We present a novel nanosecond laser-based high-throughput surface nanostructuring (nHSN) process that can simultaneously create random nanostructures and attain desirable surface chemistry over large-area metal alloy surfaces. nHSN consists of two sequential steps: (1) nanosecond laser texturing (NLT) and (2) chemical immersion treatment (CIT). NLT step in water confinement (wNLT) does not generate topological patterns but preconditions the metal surface chemically and mechanically. Our analysis shows that surface nanostructuring results from a combined effect of chemical etching and attachment of functional groups during the CIT phase of nHSN. A proper silane reagent can be selected for the CIT phase to achieve the desired surface wetting behavior, while laser parameters can also be adjusted during the NLT phase to finely tune the nanostructuring mechanism. nHSN nanostructures with fluorosilane chemistry repel water, while those with cyanosilane chemistry attract water. Extreme wettability including superhydrophobicity and superhydrophilicity is assessed for multiple engineering metal alloys including aluminum, steel and titanium alloys. Compared with existing ultrashort laser-based surface-texturing methods, the nHSN laser scan time represents a significant improvement in processing efficiency and enables a practical throughput for large-area processing of engineering alloys.

Effects of Thermal Annealing and Selective Chemical Etching on Structural and Optical Properties of GaAsBi Epilayer with Droplet Systems.

A GaAs1-xBix layer was grown by molecular beam epitaxy (MBE) with a low Bi content (2.3%) on GaAs maintaining the substrate at a non-rotating state and was then annealed at 750 °C, 800 °C and 850 °C. Each sample that was covered with droplets was investigated by using the Atomic Force Microscopy (AFM), Electrostatic Force Microscopy (EFM) and Photoluminescence (PL) techniques. The surface properties of the GaAs1-xBix layer were investigated by AFM and observed to have a droplet system, which was composed of a donut and a tail. The optical quality of the samples was enhanced after thermal annealing up to 800 °C, and the maximum PL intensity was obtained at 750 °C. AFM images revealed that the shape of the droplet and tail changed with increasing annealing temperature. EFM images revealed a phase separation on the surface droplet system. To explore the nature of the droplets, previously claimed to be made of Ga and/or Bi, and their effect on PL spectrum, a chemical etch procedure was carried out by using diluted solutions of H₂SO₄ and/or HCl. We showed that droplets may be efficiently removed from the surface, and PL intensity could be improved by using a proper sequence of chemical etching procedures. Furthermore, the presence of two different phases for the droplet-system observed by EFM was also confirmed by the selective etching procedure.

Effect of photo chemical etching and electro chemical etching on the topography of porous silicon wafers surfaces

In This research we study the effect of photo chemical etching and electrochemical etching on topography of porous silicon surfaces, the results showed that photo chemical etching produced roughness silicon layer which can have thickness be less of porous silicon layer which is produced by electro chemical etching When all the wafers have same etching time and hydrofluoric solution (HF) concentration, the wafers have same resistance (10 Ω.cm).
 Also the results showed the roughness of porous silicon layers produced by electro chemical method which is bigger than the roughness of porous silicon layers produced by photo chemical method and the results of roughness of porous silicon layers, Pore diameter and porous layer thickness were produced by electro chemical method (1.55(µm) ((0.99(µm)) and ((1.21(µm) respectively), the results of roughness of porous silicon layers, Pore diameter and porous layer thickness were produced by photo chemical method 0.63)) nm -1.55)) (µm) ),so the (84.9 (nm)- and (3.94(nm) respectively .
 This is reinforces because of using the electro chemical to etching the wafer surf ace of bulk silicon and changing it to roughness silicon surface be share in success of many practicalities.

Preparation of Ag/graphene composite films by three-component spray-spin-spray coating on surface modified PET substrate

We report a novel method of three-component spray-spin-spray coating to prepare uniform and dense Ag/graphene nanosheet (Ag/GNS) composite films on a surface modified polyethylene terephthalate (PET) substrate. Compared with an untreated sample, the adhesion between composite films and the substrate was significantly enhanced due to the effects of chemical etching and molecular grafting. From the results of the four-probe test, the sheet resistance of hybrid films of Ag/GNS-5 reduced by 60% compared to the pristine Ag films, which was due to the efficient deposition of GNS by spray-spin-spray coating method. Meanwhile, a variety of complex flexible patterns were successfully fabricated with the help of the masking method. This means that the method could provide an efficient and low cost way for flexible electronics production of various complex flexible metallic coatings in practice.

The effect of chemical and physical imperfections in zircon grains in influencing the U-Pb age analyses: Insights from zircon fission track etching

Understanding the chemical etching effects in the crystalline structure of zircon grains is crucial to know their chemical composition, morphology and isotopic geochemistry. After chemical etching, the zircon grain can be classified as homogeneous heterogeneous, hybrid and anomalous depending on the surface fission-track density observed under an optical microscope. The complementary techniques such as optical microscopy, micro-Raman spectroscopy, scanning electron microscopy (imaging by cathodoluminescence and secondary electrons) and electron microprobe, were employed to characterize the zircon grain surfaces from Igneous, Metamorphic and Sedimentary rocks before and after chemical etching, except for Raman spectroscopy. Measurements of U-Pb age are concordant in areas on the grain surface with uniform fission-track density. The chemical and isotopic analyses show that the etching is capable of revealing the different layer imperfections of the zircon crystalline structure, which can be inherent in its crystallization or acquired during its geological history. Therefore, identification of crystallographic preserved areas on the zircon surface, which are associated with uniform fission-track density, helps to get highly concordant U-Pb ages. In general, the results showed that the U-Pb system depends significantly on the amorphization degree of the zircon crystalline structure, which in most cases can only be revealed by etching.

Development and characterization of repeating macro and micro geometric surface features on plain carbon steel using chemical etching

PDF This paper investigates the use of chemical etching to develop repeating macro and micro geometric surface features on plain carbon steel. Important properties can be imparted in a material by the use of these surface features or textures leading to enhanced corrosion resistance in plain carbon steels. Maskant perforated with pinholes combined with standard chemical etching methods was used to create repeating features on the sample’s surface. Surface characterization was carried out using optical materials analysis microscopy and dynamic-mode imaging using an Atomic Force Microscope. Surface profiles were evaluated based on their center-to-center distance, surface topography and average surface roughness. Comparison with control sample revealed the effects of chemical etching in terms of changes in the average surface roughness and surface topography. Limitations were observed in the control of etchant flow to sample’s surface. However, the results were significant in refinement of the chemical etching methodology for this application.

Effect of chemical etching of resistance wire surface on the strength and failure mechanism of the resistance‐welded joint of polyetherimide composites

ABSTRACTThe surface modification of stainless‐steel (SS) mesh was carried out by chemical etching for different time, and then, the etched SS meshes were used as the interlayer heating element for resistance welding of glass fabric‐reinforced polyetherimide (GF/PEI) composite laminates. The hydrophobicity and tensile strength of the etched and untreated SS wires and interfacial shear strength (IFSS) between SS wire and PEI resin were investigated by dynamic contact angle (DCA) analyzer and single fiber pull‐out test to evaluate the influence of the degree of chemical etching on the bonding strength of PEI resin and SS surface. Tensile lap‐shear strength (LSS) and scanning electron microscope (SEM) analysis were performed to investigate the welding interface strength and fracture morphologies of the resistance‐welded joint of the GF/PEI laminates. The hydrophobicity and tensile strength of SS wires were increased and decreased respectively with etching time (te). The IFSS of SS wire/PEI resin showed an improvement with te. The LSS was increased first and then decreased with te, and the optimal te was 30 min when LSS reached the maximum. Fracture analysis showed the main failure mode of the welded joints was the interlayer debonding when welding time (tw) was insufficient. With the extension of tw, the failure mode gradually switched into the intralayer tearing of the SS implant. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47879.

Effects of Wet Chemical Etching on Scratch Morphology and Laser Damage Resistance of Fused Silica

Brittle scratches are responsible for the damage ignition when exposed to pulsed UV laser. We investigated the morphology evolution and damage resistance of glass with HF etching. The light intensity around scratches is found to increase with the dimension of scratches. Laser damage tends to be initiated at scratches edge and this is correlated with the peak electrical/light intensification and/or the mechanical weakening due to the chevron-cracks along the scratch. Moreover, the laser-induced damage threshold (LIDT) fluctuates when the length of chevron cracks varied and/or the electric/light intensification factor (LIF) is increased with the size of scratches in chemical etching.