Search results for "Isotropic etching"
showing 10 items of 26 documents
Sensing properties of assembled Bi2S3nanowire arrays
2015
Bismuth sulfide (Bi2S3) nanowires were grown in porous aluminium oxide template and a selective chemical etching was applied to transfer the nanowires to a solution. Well aligned nanowire arrays were assembled on pre-patterned silicon substrates employing dielectrophoresis. Electron beam lithography was used to connect aligned individual nanowires to the common macroelectrode. In order to evaluate the conductometric sensing performance of the Bi2S3 nanowires, current–voltage characteristics were measured at different relative humidity (RH) levels (5–80%) / argon medium. The response of the Bi2S3 nanowires depending of RH is found to be considerably different from those reported for other ty…
Thalassiosira pseudonana diatom as biotemplate to produce a macroporous ordered carbon-rich material
2008
Abstract Ordered macroporous–mesoporous carbonaceous materials were produced as a direct replica of the Thalassiosira pseudonana diatom by infiltration of the skeleton with furfuryl alcohol. The final carbon-rich material preserves the macropores of the diatom acting as bio-template and new hierarchical macro–mesopores appears as the silica is eliminated through chemical etching. The final solid can be described as an organized array of carbon macrotubes. In order to understand the progressive silica etching and the subsequent effect on the final carbon material, different etching reagents have been used. Moreover, the similar pore topology of T. pseudonana and the well known MCM-41 mesopor…
Optimisation of TA6V alloy surface laser texturing using an experimental design approach
2008
International audience; Active surfaces of plastic injection moulds are nowadays textured using classical techniques (chemical etching or EDM). Replacement of these technologies by a laser technology introduces a big flexibility: absence of mechanical contact with the tool, decrease of the effluent's volume and a big machining precision, even in the case of the complex forms as injection moulds for example. This paper reports the experimental study of the surface laser texturing of TA6V alloy. The influence of the operating factors on the laser texturing process has been studied using two experimental approaches: Taguchi methodology and response surface methodology (RSM). Empirical models h…
The effect of substrate roughness on the static friction of CuO nanowires
2012
Abstract The dependence of static friction on surface roughness was measured for copper oxide nanowires on silicon wafers coated with amorphous silicon. The surface roughness of the substrate was varied to different extent by the chemical etching of the substrates. For friction measurements, the nanowires (NWs) were pushed by an atomic-force microscope (AFM) tip at one end of the NW until complete displacement of the NW was achieved. The elastic bending profile of a NW during this manipulation process was used to calculate the ultimate static friction force. A strong dependence of static friction on surface roughness was demonstrated. The real contact area and interfacial shear strength wer…
Ultrathin silicon nanowires for optical and electrical nitrogen dioxide detection
2021
The ever-stronger attention paid to enhancing safety in the workplace has led to novel sensor development and improvement. Despite the technological progress, nanostructured sensors are not being commercially transferred due to expensive and non-microelectronic compatible materials and processing approaches. In this paper, the realization of a cost-effective sensor based on ultrathin silicon nanowires (Si NWs) for the detection of nitrogen dioxide (NO2) is reported. A modification of the metal-assisted chemical etching method allows light-emitting silicon nanowires to be obtained through a fast, low-cost, and industrially compatible approach. NO2 is a well-known dangerous gas that, even wit…
Microstructure of freestanding single-crystalline Ni2MnGa thin films
2011
Abstract The complex crystal structure and variant distribution of single-crystalline freestanding Ni–Mn–Ga films was studied in detail using X-ray diffraction in two- and four-circle geometry. Selective chemical etching of a chromium buffer layer facilitates the release of the rigid MgO substrate that would inhibit magnetically induced reorientation (MIR) of variants. The substrate-constrained as well as the freestanding films possess identical crystal structure featuring a seven-layered (pseudo-)orthorhombic modulation (7 M/14 M). Of the 12 different variants observed before and after releasing the film from the substrate, four are predominantly represented. These have the short c -axis a…
MeV–GeV ion induced dislocation loops in LiF crystals
2014
Abstract Formation of prismatic dislocation loops and evolution of dislocation structure in LiF crystals irradiated with swift 238U and 36S ions of specific energy 11 MeV/u at fluences up to 1013 ions cm−2 has been investigated using chemical etching and AFM. It has been shown that prismatic dislocations are formed in the stage of track overlapping above threshold fluences Φ ≈ 109 U cm−2 and Φ ≈ 1010 S cm−2. The diameter of dislocation loops reaches 600–1000 nm for 238U ions and 200 nm for 36S ions. The dislocations created by 238U ions are arranged in rows along the direction of ion beam, whereas 36S ions create freely distributed dislocation loops each of them being oriented along the ion…
Coating and functionalization of high density ion track structures by atomic layer deposition
2016
In this study flexible TiO 2 coated porous Kapton membranes are presented having electron multiplication properties. 800 nm crossing pores were fabricated into 50 m thick Kapton membranes using ion track technology and chemical etching. Consecutively, 50 nm TiO 2 films were deposited i nto the pores of the Kapton membranes by atomic layer deposition using Ti( i OPr) 4 and water as precursors at 250 °C. The TiO 2 films and coated membranes were studied by scanning electro n microscopy (SEM), X - ray diffraction (XRD) and X - ray reflectometry (XRR). Au metal electrod e fabrication onto both sides of the coated foils was achieved by electron beam evaporation. The electron multipliers were o…
Formation of dislocations in LiF irradiated with 3He and 4He ions
2018
Influence of the irradiation with 13.5 MeV 3He and 5 MeV 4He ions on the micro-structure and mechanical properties of LiF single crystals was studied. The depth profiles of nanoindentation, dislocation mobility, selective chemical etching and photoluminescence served for the characterization of damage. Strong ion-induced increase of hardness and decrease in dislocation mobility at the stage of track overlapping due to accumulation of dislocations and other extended defects was observed. At high fluences (1015 ions/cm2) the hardness saturates at about 3.5 GPa (twofold increase in comparison to a virgin crystal) thus confirming high efficiency of light projectiles in modifications of structur…
Porous silicon photoluminescence biosensor for rapid and sensitive detection of toxins
2017
A rapid and low cost photoluminescence (PL) immunosensor for the determination of low concentrations of Ochratoxin A(OTA) and Aflatoxine B1 (AfB1) has been developed. This biosensor was based on porous silicon (PSi) fabricated by metal-assisted chemical etching (MACE) and modified by antibodies against OTA/AfB1 (anti-OTA/anti-AfB1). Biofunctionalization method of the PSi surface by anti-OTA/ anti-AfB1 was developed. The changes of the PL intensity after interaction of the immobilized anti-OTA/anti-AfB1with OTA/AfB1 antigens were used as biosensor signal, allowing sensitive and selective detection of OTA/AfB1 antigens in BSA solution. The sensitivity of the reported optical biosensor towards…