In the past few decades,inspired by the superhydrophobic surfaces(SHPS)of animals and plants such as lotus leaves,rose petals,legs of water striders,and wings of butterflies,preparing metal materials with metallic SHP...In the past few decades,inspired by the superhydrophobic surfaces(SHPS)of animals and plants such as lotus leaves,rose petals,legs of water striders,and wings of butterflies,preparing metal materials with metallic SHPS(MSHPS)have attracted great research interest,due to the great prospect in practical applications.To obtain SHPS on conventional metal materials,it is necessary to construct rough surface,followed by modification with low surface energy substances.In this paper,the action mechanism and the current research status of MSHPS were reviewed through the following aspects.Firstly,the model of wetting theory was presented,and then the progress in MSHPS preparation through chemical etching method was discussed.Secondly,the applications of MSHPS in self-cleaning,anti-icing,corrosion resistance,drag reduction,oil-water separation,and other aspects were introduced.Finally,the challenges encountered in the present application of MSHPS were summarized,and the future research interests were discussed.展开更多
In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching proc...In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.展开更多
Solid-state nanopores with controllable pore size and morphology have huge application potential.However,it has been very challenging to process sub-10 nm silicon nanopore arrays with high efficiency and high quality ...Solid-state nanopores with controllable pore size and morphology have huge application potential.However,it has been very challenging to process sub-10 nm silicon nanopore arrays with high efficiency and high quality at low cost.In this study,a method combining metal-assisted chemical etching and machine learning is proposed to fabricate sub-10 nm nanopore arrays on silicon wafers with various dopant types and concentrations.Through a SVM algorithm,the relationship between the nanopore structures and the fabrication conditions,including the etching solution,etching time,dopant type,and concentration,was modeled and experimentally verified.Based on this,a processing parameter window for generating regular nanopore arrays on silicon wafers with variable doping types and concentrations was obtained.The proposed machine-learning-assisted etching method will provide a feasible and economical way to process high-quality silicon nanopores,nanostructures,and devices.展开更多
We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the c...We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated.展开更多
Color filters are produced using semiconductor production techniques although problems with low yield remain to be addressed. This study presents a new means of selective removal using excimer irradiation, chemical et...Color filters are produced using semiconductor production techniques although problems with low yield remain to be addressed. This study presents a new means of selective removal using excimer irradiation, chemical etching, or electrochemical machining on the fifth generation TFT LCDs. The selective removal of microstructure layers from the color filter surface of an optoelectronic flat panel display, as well as complete removal of the ITO thin-films, RGB layer, or resin black matrix (BM) layer from the substrate is possible. Individual defective film layers can be removed, or all films down to the Cr layer or bare glass can be completely eliminated. Experimental results demonstrate that defective ITO thin-films, RGB layers, or the resin BM layer can now be recycled with a great precision. When the ITO or RGB layer proves difficult to remove, excimer light can be used to help with removal. During this recycling process, the use of 225 nm excimer irradiation before chemical etching, or electrochemical machining, makes removal of stubborn film residues easy, effectively improving the quality of recycled color filters and reducing fabrication cost.展开更多
Several fundamental problems in hydrophobic force measurements using atomic force microscope (AFM) are dis-cussed in this paper. A novel method for colloid probe preparation based on chemical etching technology is pro...Several fundamental problems in hydrophobic force measurements using atomic force microscope (AFM) are dis-cussed in this paper. A novel method for colloid probe preparation based on chemical etching technology is proposed, which is specially fit for the unique demands of hydrophobic force measurements by AFM. The features of three different approaches for determining spring constants of rectangular cantilevers, including geometric dimension, Cleveland and Sader methods are com-pared. The influences of the sizes of the colloids on the measurements of the hydrophobic force curves are investigated. Our experimental results showed that by selecting colloid probe with proper spring constant and tip size, the hydrophobic force and the complete hydrophobic interaction force curve can be measured by using AFM.展开更多
A series of experiments were conducted to systematically study the effects of etching conditions on GaN by a con-venient photo-assisted chemical （PAC） etching method. The solution concentration has an evident influe...A series of experiments were conducted to systematically study the effects of etching conditions on GaN by a con-venient photo-assisted chemical （PAC） etching method. The solution concentration has an evident influence on the surface morphology of GaN and the optimal solution concentrations for GaN hexagonal pyramids have been identified. GaN with hexagonal pyramids have higher crystal quality and tensile strain relaxation compared with as-grown GaN. A detailed anal- ysis about evolution of the size, density and optical property of GaN hexagonal pyramids is described as a function of light intensity. The intensity of photoluminescence spectra of GaN etched with hexagonal pyramids significantly increases compared to that of as-grown GaN due to multiple scattering events, high quality GaN with pyramids and the Bragg effect.展开更多
The quality factor(Q factor)is a crucial performance parameter for resonators.In this paper,a novel release method for highquality micro fused silica shell resonators with teeth-like tines with good surface morphology...The quality factor(Q factor)is a crucial performance parameter for resonators.In this paper,a novel release method for highquality micro fused silica shell resonators with teeth-like tines with good surface morphology is proposed.This method is based on femtosecond laser-assisted chemical etching.First,the optimal energy range of femtosecond laser modification is obtained through mechanism analysis.Second,the optimal parameters for a straight line and arc pattern are determined by optimizing the average output power,processing speed,and processing spacing.The results demonstrate why edge breakage in rounded corners is easy under different parameters.Finally,according to these conclusions,the processing is performed on a micro fused silica shell resonator with a Q factor exceeding 6 million.In addition,subsurface damage is rare throughout the fabrication process,and the surface roughness of the released cross section reaches the nanometer level.The improved Q factor helps suppress mechanical thermal noise and reduce zero bias and zero bias drift,constituting the primary method for enhancing the performance of the resonant gyroscope.展开更多
A GaSb crystal incorporated with Mn has been grown by the Bridgman method on the Polizon facility onboard the FOTON-M3 spacecraft. Structural defects and growth striations have been successfully revealed by the chemic...A GaSb crystal incorporated with Mn has been grown by the Bridgman method on the Polizon facility onboard the FOTON-M3 spacecraft. Structural defects and growth striations have been successfully revealed by the chemical etching method. By calculating various parameters of the convection, the striation patterns can be explained, and the critical value of the Taylor number, which characterizes the convective condition of the rotating magnetic field induced azimuthal flow, was shown. The stresses generated during crystal growth can be reflected by the observations of etch pit distribution and other structural defects. Suggestions for improving the space experiment to improve the quality of the crystal are given.展开更多
The thin, long length and high smoothness silica photonic nanowires and taper optical fiber were fabricated using a simple and low cost chemical etching method. A two-steps wet etch process were used consisting of etc...The thin, long length and high smoothness silica photonic nanowires and taper optical fiber were fabricated using a simple and low cost chemical etching method. A two-steps wet etch process were used consisting of etching with 30% HF acid to remove cladding and 24% HF acid to decrease fiber core diameter. An approach for on-line monitoring of etching using 1300 nm light power transmitted in the optical fiber was used to determine the diameter of the remaining core and showed a transition between two different operation regimes of nanofiber from the embedded regime, where the mode was isolated from the environment, to the evanescent regime. The data indicated that the diameter of the silica fiber decreased linearly for both 30% and 24% HF acid with 1.2 and 0.1/zm/min grad diameter, respectively at room temperature, and more than 70% of the mode intensity could propagate outside fiber when the core diameter was less than 1μm. The results of fiber taper showed that the fiber was tapered by a factor of 20 while retaining a thin core structure and leaving about more than 85% of core structure.展开更多
ZnO thin films were prepared by a chemical etching method and their wettability was investigated. The structure and surface composition structure were characterized by means of scanning electron microscopy, X-ray phot...ZnO thin films were prepared by a chemical etching method and their wettability was investigated. The structure and surface composition structure were characterized by means of scanning electron microscopy, X-ray photoelectronic spectrometry（XPS）, X-ray diffraction（XRD） and Raman spectrometry. These analyses reveal that the etched films were large-scale micro-nanohierarchical structures composed of a Zn core and a ZnO coating. Superhy- drophobic surfaces with water contact angles of over 150~ were obtained by n-octadecanethiol（ODT） modification. The XPS and Raman results indicate that ODT molecules were bound to the ZnO surface with the S head group by forming Zn--S bond.展开更多
In this paper,Ni_(3)S_(2)nanosheet(NS)was generated by chemical etching with sodium sulfide directly on the nickel foam(NF),which was induced by dielectric barrier discharge plasma in liquid.Compared with other chemic...In this paper,Ni_(3)S_(2)nanosheet(NS)was generated by chemical etching with sodium sulfide directly on the nickel foam(NF),which was induced by dielectric barrier discharge plasma in liquid.Compared with other chemical etching methods of nickel-based nanomaterials,this method was not only rapid(40 min)and mild(at room temperature and atmospheric pressure),but also showed consistent stability and good reproducibility.The Ni_(3)S_(2)NS/NF electrode showed excellent performance in the electrochemical detection of formaldehyde under alkaline conditions.It had a good linear relationship with the concentration of formaldehyde in the range of 0.002-5.45 mmol/L(R^(2)=0.9957)and the limit of detection(LOD)was 1.23μmol/L(S/N=3).The sensitivity was 1286.9μA L mmol^(–1)cm^(–2),and the response time was about 5 s.The plasma-induced chemical etching strategy provides a simple and stable electrode preparation method,which has great application prospects in nonenzymatic electrochemical sensors.展开更多
Porous silicon （PSi） prepared from Pt metal-assisted chemical etching （MACE） was demonstrated to possess higher hydrosi- lylation efficiency （-57%） than anodized PSi （-11%） by surface reaction with co-undeceny...Porous silicon （PSi） prepared from Pt metal-assisted chemical etching （MACE） was demonstrated to possess higher hydrosi- lylation efficiency （-57%） than anodized PSi （-11%） by surface reaction with co-undecenyl alcohol （UO）. Deconvolution of the SiHx （x = 1-3） stretching bands revealed the abundance of SiH2 species on MaCE PSi was 53%, -10% higher than on ano- dized samples, while both of Sill1 and Sill3 were -5% lower correspondently on MaCE PSi than on anodized samples. The surface SiHx abundances were suggested to account for the higher hydrosilylation efficiency on MaCE PSi. Optimization of Pt-assisted chemical etching parameters suggested a 7-15 nm thick Pt-coating and an etching time of 3-10 min for biochip ap- plications. Scanning electron microscopy images revealed that an isotropic top meso-porous layer was beneficial for hydrosi- lylation and long-term durability under ambient conditions. To end, an example of histidine-tagged protein immobilization and microarray was illustrated. Combining the materials＇ property, surface chemistry, and micro-fabrication technology together, we envision that silicon based biochip applications have a prosperous future.展开更多
Purpose Niobium sputtered on copper has been a popular alternative approach for superconducting radio frequency(SRF)community in the last few decades.Comparing to bulk materials of a few millimeters,high-purity niobiu...Purpose Niobium sputtered on copper has been a popular alternative approach for superconducting radio frequency(SRF)community in the last few decades.Comparing to bulk materials of a few millimeters,high-purity niobium of merely a few microns is sufficient to realize superconductivity on the coated surface.Being niobium thin film,it has been widely acknowledged that surface quality of the substrate plays a vital role in obtaining a superior niobium coating with excellent SRF performance.Therefore,proper chemical treatment of the substrate before coating is crucial and the ultimate goal is to create a smooth and defect-free surface.Prior to the design of a cavity etching system,the mechanism of SUBU as well as two industry-used solutions is studied in detail on samples.Methods Copper samples were first pre-treated by mechanical grinding to remove fabrication damages,obvious defects and visible impurities.Two chemical solutions widely used in industries were subsequently chosen to etch the samples.Finally,the established SUBU solution was used independently on these pre-treated samples for comparison.Surface morphology and etching rate were measured accordingly.Results and conclusions Mirror-like copper surface was created by using the SUBU solution thus qualified for subsequent niobium sputtering,while the other two solutions used in industries were less effective with nonideal surface morphology.The chemical reactions,the experimental requisites and the involved processes are extensively elucidated for all three solutions.Limitations for SUBU were examined,and the optimum ratio of the chemical bath volume to sample surface area was also determined.These investigations will serve as an important guidance for the development of a chemical etching system for elliptical copper cavities.展开更多
Morphology of nonpolar （1120） a-plane GaN epilayers on r-plane （1102） sapphire substrate grown by low-pressure metal-organic vapour deposition was investigated after KOH solution etching. Many micron- and nano-met...Morphology of nonpolar （1120） a-plane GaN epilayers on r-plane （1102） sapphire substrate grown by low-pressure metal-organic vapour deposition was investigated after KOH solution etching. Many micron- and nano-meter columns on the a-plane GaN surface were observed by scanning electron microscopy. An etching mechanism model is proposed to interpret the origin of the peculiar etching morphology. The basal stacking fault in the a-plane GaN plays a very important role in the etching process.展开更多
Semiconductor nuclear radiation detectors made from tertiary and quaternary compounds of cadmium telluride (CdTe) can operate at room temperature without cryogenic cooling. One of such materials that have become of gr...Semiconductor nuclear radiation detectors made from tertiary and quaternary compounds of cadmium telluride (CdTe) can operate at room temperature without cryogenic cooling. One of such materials that have become of great interest is cadmium zinc telluride selenide (CdZnTeSe). Compared to other CdTe-based materials, such as cadmium zinc telluride (CdZnTe), CdZnTeSe can be grown with much less Te inclusions and sub-grain boundary networks. Chemical etching is often used to smoothen wafer surfaces during detector fabrication. This paper presents the characterization of CdZnTeSe that is chemically etched using bromine methanol solution. Infrared imaging shows that the wafer has no sub-grain boundary networks that often limit detector performance. The current-voltage (I-V) characterization experiment gave a resistivity of 4.6 × 10<sup>10</sup> Ω-cm for the sample. The I-V curve was linear in the ±10 to ±50 volts range. An energy resolution of 7.2% was recorded at 100 V for the 59.6-keV gamma line of <sup>241</sup>Am.展开更多
In this research we try to investigate the optimum etching time for the tracks originate in (CR-39) solid state nuclear track detector after irradiated with alpha source (<sup>241</sup>Am) using three diff...In this research we try to investigate the optimum etching time for the tracks originate in (CR-39) solid state nuclear track detector after irradiated with alpha source (<sup>241</sup>Am) using three different etching techniques: the traditional method (water bath), microwaves and ultrasound devices. The track etching parameters: bulk etch rate (V<sub>B</sub>), track etch rate (V<sub>T</sub>), track etch rate ratio evaluates (V), critical angle (θ<sub>C</sub>), and etching efficiency (η) were calculated in this research. It’s seen that the optimum etching time was ranging with (60 - 150 min), (20 - 30 min) and (60 - 120 min) when etching with water bath, microwave and ultrasound respectively. Also we observed that the critical angle was (24.29) when etching CR-39 detector with microwave. This value is lower than the critical angles values for the detector etched with water bath or ultrasound;thus it can be the optimum magnitude because its decrease leads to increasing the number of the tracks appeared in the detector and the etching efficiency.展开更多
Mesa etching technology is considerably important in the Gunn diode fabrication process. In this paper we fabricate InP Gunn diodes with two different kinds of chlorine-based etchants for the mesa etching for comparat...Mesa etching technology is considerably important in the Gunn diode fabrication process. In this paper we fabricate InP Gunn diodes with two different kinds of chlorine-based etchants for the mesa etching for comparative study. We use two chlorine-based etchants, one is HCl-based solution （HC1/H3PO4）, and the other is Cl2-based gas mixture by utilizing inductively coupled plasma system （ICP）. The results show that the wet etching （HCl-based） offers low cost and approximately vertical sidewall, whilst ICP system （C12-based） offers an excellent and uniform vertical sidewall, and the over-etching is tiny on the top and the bottom of mesa. And the fabricated mesas of Gunn diodes have average etching rates of 0.6 p.m/min and 1.2 pm/min, respectively. The measured data show that the current of Gunn diode by wet etching is lower than that by ICP, and the former has a higher threshold voltage. It provides a low-cost and reliable method which is potentially applied to the fabrication of chip terahertz sources.展开更多
In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this ...In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this SSNTD, were determined by measuring the average initial thickness (before etching) and residual thickness after 80 to 135 minutes chemical etching in the standard conditions, using an electronic comparator. These results allowed the calculation of the bulk etch rate of this detector in a simple way. The mean value obtained is (3.21 ± 0.21) μm/h. This value is in close agreement with those reported by different authors. It is an important parameter for alpha track counting on the sensitive surface of this polymeric detector after chemical etching because track density depends extremely on its removed layer. This SSNTD was then used for environmental radon gas monitoring in Côte d’Ivoire.展开更多
To improve the processing efficiency and extend the tuning range of 3D isotropic fabrication,we apply the simultaneous spatiotemporal focusing(SSTF)technique to a high-repetition-rate femtosecond(fs)fiber laser system...To improve the processing efficiency and extend the tuning range of 3D isotropic fabrication,we apply the simultaneous spatiotemporal focusing(SSTF)technique to a high-repetition-rate femtosecond(fs)fiber laser system.In the SSTF scheme,we propose a pulse compensation scheme for the fiber laser with a narrow spectral bandwidth by building an extra-cavity pulse stretcher.We further demonstrate truly 3D isotropic microfabrication in photosensitive glass with a tunable resolution ranging from 8μm to 22μm using the SSTF of fs laser pulses.Moreover,we systematically investigate the influences of pulse energy,writing speed,processing depth,and spherical aberration on the fabrication resolution.As a proof-of-concept demonstration,the SSTF scheme was further employed for the fs laser-assisted etching of complicated glass microfluidic structures with 3D uniform sizes.The developed technique can be extended to many applications such as advanced photonics,3D biomimetic printing,micro-electromechanical systems,and lab-on-a-chips.展开更多
基金the financial support of Shanghai Pujiang Program(22PJD001)the Scientific Research Project from Science and Technology Commission of Shanghai Municipality(19DZ1204903)the Fundamental Research Funds for the Central Universities(2232021G-11)。
文摘In the past few decades,inspired by the superhydrophobic surfaces(SHPS)of animals and plants such as lotus leaves,rose petals,legs of water striders,and wings of butterflies,preparing metal materials with metallic SHPS(MSHPS)have attracted great research interest,due to the great prospect in practical applications.To obtain SHPS on conventional metal materials,it is necessary to construct rough surface,followed by modification with low surface energy substances.In this paper,the action mechanism and the current research status of MSHPS were reviewed through the following aspects.Firstly,the model of wetting theory was presented,and then the progress in MSHPS preparation through chemical etching method was discussed.Secondly,the applications of MSHPS in self-cleaning,anti-icing,corrosion resistance,drag reduction,oil-water separation,and other aspects were introduced.Finally,the challenges encountered in the present application of MSHPS were summarized,and the future research interests were discussed.
基金Project (2011A090200123) supported by Industry-Universities-Research Cooperation Project of Guangdong Province and Ministry of Education of ChinaProject (111gpy06) supported by Fundamental Research Funds for the Central Universities,ChinaProject (101055807) supported by the Innovative Experiment Plan Project for College Students of Sun Yat-sen University,China
文摘In order to obtain bioelectrical impedance electrodes with high stability, the chemical etching process was used to fabricate the copper electrode with a series of surface microstructures. By changing the etching processing parameters, some comparison experiments were performed to reveal the influence of etching time, etching temperature, etching liquid concentration, and sample sizes on the etching rate and surface microstructures of copper electrode. The result shows that the etching rate is decreased with increasing etching time, and is increased with increasing etching temperature. Moreover, it is found that the sample size has little influence on the etching rate. After choosing the reasonable etching liquid composition （formulation 3）, the copper electrode with many surface microstructures can be obtained by chemical etching process at room temperature for 20 rain. In addition, using the alternating current impedance test of electrode-electrode for 24 h, the copper electrode with a series of surface microstructures fabricated by the etching process presents a more stable impedance value compared with the electrocardiograph （ECG） electrode, resulting from the reliable surface contact of copper electrode-electrode.
基金supported by the National Natural Science Foundation of China[Grant Nos.51975127,U20A6004]the Guangdong-Hong Kong Technology Coopeartion[Grant No.GHP/112/19GD]from Hong Kong Innovation and Technology Commission+1 种基金Research and Development Program of Guangdong Province[Grant No.2020A0505140008]the Fund of Key-Area Research and Development Program of Guangdong Province[Grant No.2018B090906002]。
文摘Solid-state nanopores with controllable pore size and morphology have huge application potential.However,it has been very challenging to process sub-10 nm silicon nanopore arrays with high efficiency and high quality at low cost.In this study,a method combining metal-assisted chemical etching and machine learning is proposed to fabricate sub-10 nm nanopore arrays on silicon wafers with various dopant types and concentrations.Through a SVM algorithm,the relationship between the nanopore structures and the fabrication conditions,including the etching solution,etching time,dopant type,and concentration,was modeled and experimentally verified.Based on this,a processing parameter window for generating regular nanopore arrays on silicon wafers with variable doping types and concentrations was obtained.The proposed machine-learning-assisted etching method will provide a feasible and economical way to process high-quality silicon nanopores,nanostructures,and devices.
基金Supported by the National Basic Research Program of China under Grant No 2012CB921804the National Natural Science Foundation of China under Grant Nos 11204236 and 61308006the Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘We demonstrate a method of fabricating through micro-holes and micro-hole arrays in silicon using femtosecond laser irradiation and selective chemical etching. The micro-hole formation mechanism is identified as the chemical reaction of the femtosecond laser-induced structure change zone and hydrofluoric acid solution. The morphologies of the through micro-holes and micro-hole arrays are characterized by using scanning electronic microscopy, The effects of the pulse number on the depth and diameter of the holes are investigated. Honeycomb arrays of through micro-holes fabricated at different laser powers and pulse numbers are demonstrated.
基金supported by the BEN TEN CO., and National Science Council contracts 98-2221-E-152-001 and 99-2221-E-152-001
文摘Color filters are produced using semiconductor production techniques although problems with low yield remain to be addressed. This study presents a new means of selective removal using excimer irradiation, chemical etching, or electrochemical machining on the fifth generation TFT LCDs. The selective removal of microstructure layers from the color filter surface of an optoelectronic flat panel display, as well as complete removal of the ITO thin-films, RGB layer, or resin black matrix (BM) layer from the substrate is possible. Individual defective film layers can be removed, or all films down to the Cr layer or bare glass can be completely eliminated. Experimental results demonstrate that defective ITO thin-films, RGB layers, or the resin BM layer can now be recycled with a great precision. When the ITO or RGB layer proves difficult to remove, excimer light can be used to help with removal. During this recycling process, the use of 225 nm excimer irradiation before chemical etching, or electrochemical machining, makes removal of stubborn film residues easy, effectively improving the quality of recycled color filters and reducing fabrication cost.
基金Project (No. 20276057) supported by the National Natural ScienceFoundation of China
文摘Several fundamental problems in hydrophobic force measurements using atomic force microscope (AFM) are dis-cussed in this paper. A novel method for colloid probe preparation based on chemical etching technology is proposed, which is specially fit for the unique demands of hydrophobic force measurements by AFM. The features of three different approaches for determining spring constants of rectangular cantilevers, including geometric dimension, Cleveland and Sader methods are com-pared. The influences of the sizes of the colloids on the measurements of the hydrophobic force curves are investigated. Our experimental results showed that by selecting colloid probe with proper spring constant and tip size, the hydrophobic force and the complete hydrophobic interaction force curve can be measured by using AFM.
基金Project supported by the National Basic Research Program of China(Grant Nos.2011CB301900,2012CB619304,and 2010CB327504)the National High Technology Research and Development Program of China(Grant No.2011AA03A103)+1 种基金the National Nature Science Foundation of China(Grant Nos.60990311,60906025,60936004,and 61176063)the Natural Science Foundation of Jiangsu Province,China(Grant Nos.BK2011010 and BK2009255)
文摘A series of experiments were conducted to systematically study the effects of etching conditions on GaN by a con-venient photo-assisted chemical （PAC） etching method. The solution concentration has an evident influence on the surface morphology of GaN and the optimal solution concentrations for GaN hexagonal pyramids have been identified. GaN with hexagonal pyramids have higher crystal quality and tensile strain relaxation compared with as-grown GaN. A detailed anal- ysis about evolution of the size, density and optical property of GaN hexagonal pyramids is described as a function of light intensity. The intensity of photoluminescence spectra of GaN etched with hexagonal pyramids significantly increases compared to that of as-grown GaN due to multiple scattering events, high quality GaN with pyramids and the Bragg effect.
基金supported by the National Natural Science Foundation of China Regional Innovation and Development Joint Fund Key Support Project(Grant No.U21A20505)the National Natural Science Foundation of China(Grant Nos.62204261 and 52205613)。
文摘The quality factor(Q factor)is a crucial performance parameter for resonators.In this paper,a novel release method for highquality micro fused silica shell resonators with teeth-like tines with good surface morphology is proposed.This method is based on femtosecond laser-assisted chemical etching.First,the optimal energy range of femtosecond laser modification is obtained through mechanism analysis.Second,the optimal parameters for a straight line and arc pattern are determined by optimizing the average output power,processing speed,and processing spacing.The results demonstrate why edge breakage in rounded corners is easy under different parameters.Finally,according to these conclusions,the processing is performed on a micro fused silica shell resonator with a Q factor exceeding 6 million.In addition,subsurface damage is rare throughout the fabrication process,and the surface roughness of the released cross section reaches the nanometer level.The improved Q factor helps suppress mechanical thermal noise and reduce zero bias and zero bias drift,constituting the primary method for enhancing the performance of the resonant gyroscope.
基金supported by the Space Agency of China and the Chinese Academy of Sciences
文摘A GaSb crystal incorporated with Mn has been grown by the Bridgman method on the Polizon facility onboard the FOTON-M3 spacecraft. Structural defects and growth striations have been successfully revealed by the chemical etching method. By calculating various parameters of the convection, the striation patterns can be explained, and the critical value of the Taylor number, which characterizes the convective condition of the rotating magnetic field induced azimuthal flow, was shown. The stresses generated during crystal growth can be reflected by the observations of etch pit distribution and other structural defects. Suggestions for improving the space experiment to improve the quality of the crystal are given.
基金carried out in School of Physics and Astronomy in University of Southampton, UK and founded by both of IIE/SRF and CARA
文摘The thin, long length and high smoothness silica photonic nanowires and taper optical fiber were fabricated using a simple and low cost chemical etching method. A two-steps wet etch process were used consisting of etching with 30% HF acid to remove cladding and 24% HF acid to decrease fiber core diameter. An approach for on-line monitoring of etching using 1300 nm light power transmitted in the optical fiber was used to determine the diameter of the remaining core and showed a transition between two different operation regimes of nanofiber from the embedded regime, where the mode was isolated from the environment, to the evanescent regime. The data indicated that the diameter of the silica fiber decreased linearly for both 30% and 24% HF acid with 1.2 and 0.1/zm/min grad diameter, respectively at room temperature, and more than 70% of the mode intensity could propagate outside fiber when the core diameter was less than 1μm. The results of fiber taper showed that the fiber was tapered by a factor of 20 while retaining a thin core structure and leaving about more than 85% of core structure.
基金Supported by the National Natural Science Foundation of China（No.50875108） and the Specialized Research Fund for the Doctoral Program of Higher Education of China（No.20100061110022）.
文摘ZnO thin films were prepared by a chemical etching method and their wettability was investigated. The structure and surface composition structure were characterized by means of scanning electron microscopy, X-ray photoelectronic spectrometry（XPS）, X-ray diffraction（XRD） and Raman spectrometry. These analyses reveal that the etched films were large-scale micro-nanohierarchical structures composed of a Zn core and a ZnO coating. Superhy- drophobic surfaces with water contact angles of over 150~ were obtained by n-octadecanethiol（ODT） modification. The XPS and Raman results indicate that ODT molecules were bound to the ZnO surface with the S head group by forming Zn--S bond.
基金the Foundation of Sichuan Normal University(No.XJ20210047)Foundation of Sichuan Department of Science and Technology(No.2017FZ0079)for financial support。
文摘In this paper,Ni_(3)S_(2)nanosheet(NS)was generated by chemical etching with sodium sulfide directly on the nickel foam(NF),which was induced by dielectric barrier discharge plasma in liquid.Compared with other chemical etching methods of nickel-based nanomaterials,this method was not only rapid(40 min)and mild(at room temperature and atmospheric pressure),but also showed consistent stability and good reproducibility.The Ni_(3)S_(2)NS/NF electrode showed excellent performance in the electrochemical detection of formaldehyde under alkaline conditions.It had a good linear relationship with the concentration of formaldehyde in the range of 0.002-5.45 mmol/L(R^(2)=0.9957)and the limit of detection(LOD)was 1.23μmol/L(S/N=3).The sensitivity was 1286.9μA L mmol^(–1)cm^(–2),and the response time was about 5 s.The plasma-induced chemical etching strategy provides a simple and stable electrode preparation method,which has great application prospects in nonenzymatic electrochemical sensors.
基金the financial support of the National Basic Research Program of China(2013CB922101)the National Natural Science Foundation of China(20827001,91027019,21021062)
文摘Porous silicon （PSi） prepared from Pt metal-assisted chemical etching （MACE） was demonstrated to possess higher hydrosi- lylation efficiency （-57%） than anodized PSi （-11%） by surface reaction with co-undecenyl alcohol （UO）. Deconvolution of the SiHx （x = 1-3） stretching bands revealed the abundance of SiH2 species on MaCE PSi was 53%, -10% higher than on ano- dized samples, while both of Sill1 and Sill3 were -5% lower correspondently on MaCE PSi than on anodized samples. The surface SiHx abundances were suggested to account for the higher hydrosilylation efficiency on MaCE PSi. Optimization of Pt-assisted chemical etching parameters suggested a 7-15 nm thick Pt-coating and an etching time of 3-10 min for biochip ap- plications. Scanning electron microscopy images revealed that an isotropic top meso-porous layer was beneficial for hydrosi- lylation and long-term durability under ambient conditions. To end, an example of histidine-tagged protein immobilization and microarray was illustrated. Combining the materials＇ property, surface chemistry, and micro-fabrication technology together, we envision that silicon based biochip applications have a prosperous future.
基金Wewould like to thank Dr.ChaoDong for helping with sample characterizations.We are especially grateful to LNER-team at IHEP for providing the laboratory and necessary facilities for chemical experiments.This work has been supported by the Platform for Advanced Photon Source Technology(PAPS)project and Pioneer“Hundred Talents Program”of Chinese Academy of Sciences.
文摘Purpose Niobium sputtered on copper has been a popular alternative approach for superconducting radio frequency(SRF)community in the last few decades.Comparing to bulk materials of a few millimeters,high-purity niobium of merely a few microns is sufficient to realize superconductivity on the coated surface.Being niobium thin film,it has been widely acknowledged that surface quality of the substrate plays a vital role in obtaining a superior niobium coating with excellent SRF performance.Therefore,proper chemical treatment of the substrate before coating is crucial and the ultimate goal is to create a smooth and defect-free surface.Prior to the design of a cavity etching system,the mechanism of SUBU as well as two industry-used solutions is studied in detail on samples.Methods Copper samples were first pre-treated by mechanical grinding to remove fabrication damages,obvious defects and visible impurities.Two chemical solutions widely used in industries were subsequently chosen to etch the samples.Finally,the established SUBU solution was used independently on these pre-treated samples for comparison.Surface morphology and etching rate were measured accordingly.Results and conclusions Mirror-like copper surface was created by using the SUBU solution thus qualified for subsequent niobium sputtering,while the other two solutions used in industries were less effective with nonideal surface morphology.The chemical reactions,the experimental requisites and the involved processes are extensively elucidated for all three solutions.Limitations for SUBU were examined,and the optimum ratio of the chemical bath volume to sample surface area was also determined.These investigations will serve as an important guidance for the development of a chemical etching system for elliptical copper cavities.
基金Project supported by the National Key Science & Technology Special Project (Grant No. 2008ZX01002-002)the Major Program and State Key Program of National Natural Science Foundation of China (Grant Nos. 60890191 and 60736033)the Fundamental Research Funds for the Central Universities (Grant No. JY10000904009)
文摘Morphology of nonpolar （1120） a-plane GaN epilayers on r-plane （1102） sapphire substrate grown by low-pressure metal-organic vapour deposition was investigated after KOH solution etching. Many micron- and nano-meter columns on the a-plane GaN surface were observed by scanning electron microscopy. An etching mechanism model is proposed to interpret the origin of the peculiar etching morphology. The basal stacking fault in the a-plane GaN plays a very important role in the etching process.
文摘Semiconductor nuclear radiation detectors made from tertiary and quaternary compounds of cadmium telluride (CdTe) can operate at room temperature without cryogenic cooling. One of such materials that have become of great interest is cadmium zinc telluride selenide (CdZnTeSe). Compared to other CdTe-based materials, such as cadmium zinc telluride (CdZnTe), CdZnTeSe can be grown with much less Te inclusions and sub-grain boundary networks. Chemical etching is often used to smoothen wafer surfaces during detector fabrication. This paper presents the characterization of CdZnTeSe that is chemically etched using bromine methanol solution. Infrared imaging shows that the wafer has no sub-grain boundary networks that often limit detector performance. The current-voltage (I-V) characterization experiment gave a resistivity of 4.6 × 10<sup>10</sup> Ω-cm for the sample. The I-V curve was linear in the ±10 to ±50 volts range. An energy resolution of 7.2% was recorded at 100 V for the 59.6-keV gamma line of <sup>241</sup>Am.
文摘In this research we try to investigate the optimum etching time for the tracks originate in (CR-39) solid state nuclear track detector after irradiated with alpha source (<sup>241</sup>Am) using three different etching techniques: the traditional method (water bath), microwaves and ultrasound devices. The track etching parameters: bulk etch rate (V<sub>B</sub>), track etch rate (V<sub>T</sub>), track etch rate ratio evaluates (V), critical angle (θ<sub>C</sub>), and etching efficiency (η) were calculated in this research. It’s seen that the optimum etching time was ranging with (60 - 150 min), (20 - 30 min) and (60 - 120 min) when etching with water bath, microwave and ultrasound respectively. Also we observed that the critical angle was (24.29) when etching CR-39 detector with microwave. This value is lower than the critical angles values for the detector etched with water bath or ultrasound;thus it can be the optimum magnitude because its decrease leads to increasing the number of the tracks appeared in the detector and the etching efficiency.
基金supported by the Main Direction Program of Knowledge Innovation of the Chinese Academy of Sciences(Grant No.2A2011YYYJ-1123)
文摘Mesa etching technology is considerably important in the Gunn diode fabrication process. In this paper we fabricate InP Gunn diodes with two different kinds of chlorine-based etchants for the mesa etching for comparative study. We use two chlorine-based etchants, one is HCl-based solution （HC1/H3PO4）, and the other is Cl2-based gas mixture by utilizing inductively coupled plasma system （ICP）. The results show that the wet etching （HCl-based） offers low cost and approximately vertical sidewall, whilst ICP system （C12-based） offers an excellent and uniform vertical sidewall, and the over-etching is tiny on the top and the bottom of mesa. And the fabricated mesas of Gunn diodes have average etching rates of 0.6 p.m/min and 1.2 pm/min, respectively. The measured data show that the current of Gunn diode by wet etching is lower than that by ICP, and the former has a higher threshold voltage. It provides a low-cost and reliable method which is potentially applied to the fabrication of chip terahertz sources.
文摘In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this SSNTD, were determined by measuring the average initial thickness (before etching) and residual thickness after 80 to 135 minutes chemical etching in the standard conditions, using an electronic comparator. These results allowed the calculation of the bulk etch rate of this detector in a simple way. The mean value obtained is (3.21 ± 0.21) μm/h. This value is in close agreement with those reported by different authors. It is an important parameter for alpha track counting on the sensitive surface of this polymeric detector after chemical etching because track density depends extremely on its removed layer. This SSNTD was then used for environmental radon gas monitoring in Côte d’Ivoire.
基金supported by the National Key Research and Development Program of China(2019YFA0705000,2022YFA1404800)National Natural Science Foundation of China(12004221,12174107,12192254,11734009,12192251,92250304,11974218)+4 种基金Postdoctoral Innovation Talents Support Program of Shandong Province(No.SDBX2019005)Science and Technology Commission of Shanghai Municipality(21DZ1101500)Local science and technology development project of the central government(YDZX20203700001766)Shanghai Municipal Science and Technology Major ProjectNatural Science Foundation of Shandong Province(ZR2021ZD02).
文摘To improve the processing efficiency and extend the tuning range of 3D isotropic fabrication,we apply the simultaneous spatiotemporal focusing(SSTF)technique to a high-repetition-rate femtosecond(fs)fiber laser system.In the SSTF scheme,we propose a pulse compensation scheme for the fiber laser with a narrow spectral bandwidth by building an extra-cavity pulse stretcher.We further demonstrate truly 3D isotropic microfabrication in photosensitive glass with a tunable resolution ranging from 8μm to 22μm using the SSTF of fs laser pulses.Moreover,we systematically investigate the influences of pulse energy,writing speed,processing depth,and spherical aberration on the fabrication resolution.As a proof-of-concept demonstration,the SSTF scheme was further employed for the fs laser-assisted etching of complicated glass microfluidic structures with 3D uniform sizes.The developed technique can be extended to many applications such as advanced photonics,3D biomimetic printing,micro-electromechanical systems,and lab-on-a-chips.
