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Resolving ZnO-based coaxial core-multishell heterostructure by electrical scanning probe microscopy
摘要： Coaxially periodic ZnO/ZnMgO core-multishell nanowire (NW) heterostructures were grown via a metal organic chemical vapor deposition method. We investigated their electrical properties via the application of two locally resolved electrical scanning probe microscopy techniques, i.e., scanning capacitance microscopy (SCM) and scanning spreading resistance microscopy (SSRM), following a planarization process. As a result, ZnO and ZnMgO layers can be unambiguously distinguished by both techniques on NWs with diameters <1 lm and the smallest layer thickness of 10 nm, where a higher free carrier concentration along with a low resistivity is revealed for the ZnO regions in comparison to ZnMgO portions, as expected. This work demonstrates the high capability of SCM/SSRM as supplementary and effective tools for probing local electrical properties within functional complex quasi-1D heterostructures.
关键词： core-multishell nanowire,ZnMgO,ZnO,scanning spreading resistance microscopy,scanning capacitance microscopy
更新于2025-09-09 09:28:46
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[Nanostructure Science and Technology] Nanowire Electronics || Properties Engineering of III–V Nanowires for Electronic Application
摘要： Semiconductors have been the core materials of many technological advances in recent years. Silicon, the most studied and used semiconducting material, has been the center of semiconductor industry for decades because it is available abundantly and easy to dope, and silicon dioxide is a superior dielectric material in microelectronic industry. This material can be used to make computer chips, optoelectronics devices, and solar cell. Silicon reshapes the way we live and is unarguably one of the most important materials in modern society. Through its dominant role in the semiconductor industry for now, the search for alternatives is fueled by the unstoppable demand for high-performance and low-power electronics. Among different kinds of semiconductors, III–V semiconductor holds promising properties for replacing silicon, and in particular, the NW structure of III–V semiconductor has been studied extensively.
关键词： nanowire field-effect transistor,semiconductors,contact engineering,crystal engineering,III–V nanowires,surface modification,electronic application
更新于2025-09-09 09:28:46
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Decoupling the contributions to the enhancement of electrical conductivity in transparent silver nanowire/zinc oxide composite electrodes
摘要： Electrical properties of silver nanowire (AgNW)-based transparent electrodes have been improved without transmittance loss by forming a composite with zinc oxide (ZnO). Here, we identified the dominant effect responsible for the improvement of electrical conductivity of the transparent AgNW:ZnO composite electrodes by fabricating the AgNW:ZnO composite electrodes with different architectures and theoretically calculating the overall resistance of their equivalent circuits. Specifically, when we compared the overall resistances of the AgNW:ZnO electrodes with various architectures by experiment, the electrode with only the electrical bridge effect showed the lowest electrical resistance. In addition, while the theoretical overall resistances were comparable on changing the interconnect resistances between the silver nanowires in the equivalent circuits of all architectures, they decreased dramatically with the decreasing ZnO bridging resistance. Thus, it was concluded that the electrical bridge effect is more important than the capillary force effect which decreases the interconnect resistance between the silver nanowires for the enhancement of the electrical properties of AgNW:ZnO composite electrodes. It was also found that the AgNW:ZnO electrodes with only the electrical bridge effect showed better device performances when applied to optoelectronic devices such as organic photovoltaics.
关键词： electrical conductivity,silver nanowire,electrical bridge effect,zinc oxide,capillary force effect
更新于2025-09-09 09:28:46
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High density GaAs nanowire arrays through substrate processing engineering
摘要： GaAs nanowires (NWs) vertically aligned were successfully fabricated through substrate processing engineering. High-density vertical GaAs NWs are grown on n-type Si (111) substrate by molecular beam epitaxy. Systematic experiments indicate that substrate pretreatment is crucial to vertical epitaxial growth of one-dimensional (1D) nanomaterials. The substrates etched using diluted buffered oxide etch (BOE) were explored to improve the NW density and vertical. We also find that the substrate processing engineering strongly affect the morphology of GaAs NWs. Finally, we demonstrate fabrication of GaAs NW arrays on Si surface by field-emission scanning electron microscopy (FE-SEM). This single-step process indeed offers a simple and cost-effective way to obtain a large area of GaAs NW arrays without using e-beam lithography (EBL) and/or nanoimprint lithography (NIL) processes. This work provided a new approach for hight density NW arrays.
关键词： GaAs nanowire arrays,self-catalyzed,buffered oxide etch,molecular beam epitaxy
更新于2025-09-09 09:28:46
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Percolating Film of Pillared Graphene Layer Integrated with Silver Nanowire Network for Transparent and Flexible Supercapacitors
摘要： Transparent and flexible supercapacitors (TFSCs) are viable power sources for next-generation wearable electronics. The ingenious design of the transparent electrode determines the performance of TFSCs. Herein, a percolating film of a pillared graphene layer integrated with a silver nanowire network as the transparent electrode was prepared, by which TFSCs devices exhibit a significantly improved performance contrastively. At the condition of the same transmittance, about 27-72% improvement in the areal capacitance can be achieved. On the one hand, the pillars of carbon nanotube (CNT) were distributed in the graphene layer uniformly, enlarging the inner distance of adjacent graphene layers and providing open structure for extra ion transport and storage of TFSCs. On the other hand, the introduced CNT could facilitate the electron transport at the direction perpendicular to the graphene basal plane, enhancing the electronic conductivity of the graphene layer. More importantly, the formed percolating film ensures an efficient transport of electron along with the silver nanowire when it encounters the obstacle within the graphene layer, resulting in a highly conductive electrode. The TFSCs device with a good compatibility indicates a reliable practicability, which provides a facile route towards the design of high performance TFSCs.
关键词： reduced graphene oxide,silver nanowire,transparent supercapacitor,percolating film,flexible supercapacitor
更新于2025-09-09 09:28:46
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Threshold Voltage Characteristics for Silicon Nanowire Field-Effect Transistor With a Double-Layer Gate Structure
摘要： In this paper, the threshold voltage characteristics of silicon nanowire metal–oxide–semiconductor field-effect transistor (MOSFET) with a double-layer gate structure are presented. This type of device is considered to be the most promising application of nanodevice in ultralarge-scale integration, due to several advantages such as similar operation principle as the junctionless nanowire transistor, the screening effect of the upper gate (UG) to shield the lower gate MOSFETs from external electromagnetic disturbance, the tradeoff between the short channel and the thick-gate oxide layer, and the compatible fabrication process with the conventional MOS technology. In this paper, the relations of threshold voltage versus the gate length, the UG bias, the substrate bias, the drain bias, and the temperature are measured and analyzed. Moreover, the penetration effect of the UG electric field is proposed to interpret the short-channel characteristics of the device, and a piecewise curve model is presented to reveal the underlying physics of the relation of the threshold voltage versus the drain bias. The double-layer gate structure technology enables the design of many devices, such as small-signal analog circuit units, single-electron devices, and quantum bit cells.
关键词： short-channel effect,silicon nanowire (Si-NW),threshold voltage characteristics,MOS devices,Double-layer gate structure
更新于2025-09-09 09:28:46
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CeO2 Nanowire-BODIPY-Adenosine Triphosphate Fluorescent Sensing Platform for Highly Specific and Sensitive Detection of Arsenate
摘要： Effective and sensitive monitoring of arsenate in drinking water is significant for risk management of public health. Here, we demonstrated that CeO2 nanowire acted as an efficient quencher for small fluorescent molecules with phosphate group, BODIPY-adenosine triphosphate (BODIPY-ATP) and riboflavin-5'-phosphate (Rf-P), and developed CeO2 nanowire-BODIPY-ATP platform for highly selective and sensitive detection of arsenate. The response strategy was based on the competitive coordination chemistry of CeO2 nanowire between arsenate and phosphate group of BODIPY-ATP. Arsenate displaced adsorbed BODIPY-ATP to enhance fluorescence, allowing detection of arsenate down to 7.8 nM, which is lower than the WHO defined limit 130 nM. Excellent linear range of 20-150 nM and 150-1000 nM was obtained. Importantly, this system was simple in design and convenient in operation. And the platform exhibited excellent selectivity for arsenate without the interference of phosphate ions. Finally, the proposed method had been successfully employed for determination of arsenate in real water samples.
关键词： competitive coordination,BODIPY-ATP,CeO2 nanowire,arsenate,fluorescent sensing
更新于2025-09-09 09:28:46
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Transformation of single Ag nanowires into super-large AgAu elliptic rings via a water/oil interface-oriented asymmetrical etching
摘要： Nanoring as one of fascinating geometries exhibits unique size-dependent physical-chemistry properties endowed by its circular feature. However, to the best of our knowledge, super-large elliptical nanorings cannot be fabricated by the existing techniques. Herein, we successfully fabricate super-large elliptical AgAu nanorings creatively by splitting single Ag nanowires along their longitudinal axes involving oil/water interfacial self-assembly of Ag nanowires and the galvanic replacement between interfacial Ag nanowires and AuCl4? located in the water phase. The formation of AgAu nanoring is mainly attributed to the local nanomasking of Au atoms and asymmetrical etching on interfacial Ag nanowire. Additionally, as-prepared super-large elliptical AgAu nanorings with rough surfaces exhibit enhanced catalytic performance towards the reduction of p-nitrophenol due to the combination of the composition and structure effects. This strategy, without doubt, provides a convenient way for precisely carving nanoparticles, and has the potential for processing other metallic or non-metallic nanoparticles.
关键词： Ag nanowire,selective etching,AgAu nanoring,galvanic replacement,self-assembly
更新于2025-09-09 09:28:46
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Synthesis and growth mechanism of aluminum nitride nanowires via a chloride-assisted chemical vapor reaction method
摘要： We report a large scaled fabrication of AlN nanowires via a chloride-assisted chemical vapor reaction technique at 1100°C in flowing N2 atmosphere using aluminum powders as starting materials. The as-obtained hexagonal AlN nanowires had the length of hundreds of microns and diameter of 20-100 nanometers, and indicated a single crystalline characteristic. The yield production was significantly increased with ammonium chloride and aluminum chloride addition because of the formation of intermediate gaseous AlCl and HCl. The addition of ammonium chloride and aluminum chloride also promoted the formation of ferric chloride, which served as the catalyst and further facilitated the growth of AlN nanowires. The vapor–liquid–solid and vapor–solid growth mechanism are proposed and discussed in details.
关键词： growth mechanism,ammonium chloride,nanowire,Aluminum nitride,chemical vapor reaction,aluminum chloride
更新于2025-09-09 09:28:46
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Pattern recognition of messily grown nanowire morphologies applying multi-layer connected self-organized feature maps
摘要： Multi-layer connected self-organizing feature maps (SOFMs) and the associated learning procedure were proposed to achieve efficient recognition and clustering of messily grown nanowire morphologies. The network is made up by several paratactic 2-D SOFMs with inter-layer connections. By means of Monte Carlo simulations, virtual morphologies were generated to be the training samples. With the unsupervised inner-layer and inter-layer learning, the neural network can cluster different morphologies of messily grown nanowires and build connections between the morphological microstructure and geometrical features of nanowires within. Then, the as-proposed networks were applied on recognitions and quantitative estimations of the experimental morphologies. Results show that the as-trained SOFMs are able to cluster the morphologies and recognize the average length and quantity of the messily grown nanowires within. The inter-layer connections between winning neurons on each competitive layer have significant influence on the relations between the microstructure of the morphology and physical parameters of the nanowires within.
关键词： Messily grown nanowire morphologies,Artificial neural networks,Monte Carlo simulation,Pattern recognition,Self-organizing feature maps
更新于2025-09-09 09:28:46