The biosensors on basis of the pH sensor are widely utilized in the medical instruments. Zinc oxide （ZnO） has been demonstrated as a promising sensing material due to its inherent properties including wide bandgap ...
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The biosensors on basis of the pH sensor are widely utilized in the medical instruments. Zinc oxide （ZnO） has been demonstrated as a promising sensing material due to its inherent properties including wide bandgap （3.3 eV）, stability, low toxicity, biocompatibility, high electron mobility and easy fabrication. In this work, ZnO nanorod （NR） arrays was deposited on the FTO glass through hydrothermal reaction. To enhance the catalytic activity of ZnO, Au nanoparticles （NPs） synthesized by photo-reduction method were dispersed uniformly onto ZnO NRs by a simple electrostatic self-assembly method. ZnO NR arrays and Au-modified ZnO NR arrays were used as the sensing membrane of two extended-gate field-effect-transistors （EGFETs）, respectively, which were connected with a commercial MOSFET device in CD4007UB. The pH sensitivity was calculated from the linear relation between the reference voltage and the pH value in concentration under the same measurement conditions with pH ranging from 4 to 12. The ZnO NR arrays based pH sensor had a linear response of 30.87 mV/pH, while the Au-modified ZnO NR arrays showed a higher sensitivity of 40.69 mV/pH. This study suggests that the Au NPs can greatly improve the biosensing properties of ZnO NR arrays which could be ascribed to the increased electron transfer ability and electrocatalytic ability introduced by Au NPs.
Recently, self-powered devices based on a p-n heterojunction were frequently reported, but there were few report about self-powered UV detectors based on single ZnO microwire/p-Si double heterojunctions. Compared to t...
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Recently, self-powered devices based on a p-n heterojunction were frequently reported, but there were few report about self-powered UV detectors based on single ZnO microwire/p-Si double heterojunctions. Compared to the common p-n junction type device with an n-type ZnO microwire/p-Si heterostructure, the newly designed device with double heterojunctions based on a single n-type ZnO microwire and a p-type Si film displaysed interesting electrical characteristics such as a high rectification ratio and a low turn-on voltage. Under zero bias, the fabricated device had a high photosensitivity of .17*10 3 under UV illumination and a fast response time less than 0.1ms, which was shorter than that of the device at forward bias (less than 0.2ms). The security service of the device was also studied, and the result showed that the photocurrent would reach saturation when the voltage increased to a specific value. The device of the double heterojunctions of n-ZnO microwire/p-Si might be a good candidate for potential applications in photodetection, sensors and photocatalysis, and it might be used as elements for powering low-energy micro/nanosystems.
The electromagnetic parameters were measured for the mixtures of mechanical milled carbonyl iron powders （CIPs） with different mass ratios of spheroid-like particles to flake-shape particles. The results indicate th...
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The electromagnetic parameters were measured for the mixtures of mechanical milled carbonyl iron powders （CIPs） with different mass ratios of spheroid-like particles to flake-shape particles. The results indicate that mixing the sphere-like CIP particles with flake-shaped CIPs can be used to adjust effectively the electromagnetic parame- ters and enhance the absorption property in high frequency. In addition, a theoretic simulation based on the principle of superposition was carried out and compared with the microwave measurement results, indicating that the simple principle of superpo- sition can not reflect truly the internal interaction mechanism in the composites with different particle shapes.
Temperature tunable photonic crystals were fabricated based on liquid-infiltrated inverse opal films which were prepared by Tb doped SiO with a sol-gel *** photoluminescence was investigated with the photonic band gap...
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Temperature tunable photonic crystals were fabricated based on liquid-infiltrated inverse opal films which were prepared by Tb doped SiO with a sol-gel *** photoluminescence was investigated with the photonic band gap shift tuned by *** results show that obvious suppression of spontaneous emission occurs when the photonic band gap overlaps with the Tb emission band,while enhancement of the emission is observed if the emission band shifts at the edge of the band gap.
Here a two-step epitaxial synthesis method of bisectional ZnO nanowire arrays (ZNWAs) on silicon substrates has been demonstrated incorporating hydrothermal growth (HG) and CVD process. The as-received well-aligned ZN...
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Here a two-step epitaxial synthesis method of bisectional ZnO nanowire arrays (ZNWAs) on silicon substrates has been demonstrated incorporating hydrothermal growth (HG) and CVD process. The as-received well-aligned ZNWAs are confirmed to be single-crystal and growing along 〈001〉 direction, normal to the substrate. Interestingly, they show significant tapering behavior at the conjunctions, which is consistent with theoretical predictions. Therefore a layered growth mechanism is promoted involving the classical two-dimensional nucleation theory. In the proposed mechanism, the HG ZNWA provides nucleation sites for successive growth. The growth mechanism is verified by complementary investigation into conjunction morphology, which is dependent on regional Zn vapor pressure (ZVP) in the CVD process. Three types of conjunction morphologies are differentiated and the difference is explained with the growth model.
A facile and cost-effective fabrication approach of active strain sensor based on individual ZnO micro/nanowire was demonstrated. By connecting a ZnO micro/nanowire along polar growth direction with two Ag electrodes ...
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A facile and cost-effective fabrication approach of active strain sensor based on individual ZnO micro/nanowire was demonstrated. By connecting a ZnO micro/nanowire along polar growth direction with two Ag electrodes on flexible polystyrene (PS) substrate, the fabricated strain sensor was obtained as a typical M-S-M structure. The I-V characteristic of the device was highly sensitive to the strain caused by the obvious change of Schottky barrier height (SBH). Furthermore, both of the symmetric and asymmetric changes of the SBH at the source and drain were observed during device testing process. The respective contribution of piezoresistance effect and the piezoelectric effect to the change of SBHs were also systematically investigated.
The effects of various SiO2 contents on both the microstructures and properties of Ca-Ba-Al-B-Si-O glass/Al2O3 composites were investigated by FTIR, DSC, XRD and SEM. The experimental results show that increasing SiO2...
The effects of various SiO2 contents on both the microstructures and properties of Ca-Ba-Al-B-Si-O glass/Al2O3 composites were investigated by FTIR, DSC, XRD and SEM. The experimental results show that increasing SiO2 content in the glass leads to the increase of [SiO4] units, increases the continuity of glass network, and decreases the trend to crystallization of composites. The shrinkage of samples rises rapid around the glass softening temperature and the final shrinkage of samples decreases with increasing SiO2 content in the glass. Borosilicate glass/Al2O3 composites with 60wt% SiO2 sintered at 875 °C for 15 min show better properties: a bulk density of 3.10 g·cm−3, a porosity of 0.23%, a ɛ r value of 7.55 and a tan δ value of 0.00053 (measured at 10 MHz) and a well matching with Ag electrodes.
The new type of the hierarchically structured porous solid-acid catalysts described in this presentation possess a remarkable pore system,encompassing well-defined macrochannels, interconnected mesopores,intracrystall...
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The new type of the hierarchically structured porous solid-acid catalysts described in this presentation possess a remarkable pore system,encompassing well-defined macrochannels, interconnected mesopores,intracrystalline mesopores,and tunable zeolite(ZMS-5,Beta,...) micropores[1-5].These hierarchical micro-meso-macroporous zeolitic catalysts with improved stability have been synthesized via a quasi solid state chemical crystallization ***,the catalyst exhibits very strong acidity
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