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Absorption of light in a single vertical nanowire and a nanowire array
摘要： Both a single III–V semiconductor nanowire and an array of such nanowires have shown promise for solar cell applications. However, the correspondence between the optical properties of the single nanowire and the nanowire array has not been studied. Here, we perform electromagnetic modeling of InP nanowires to study this relationship. We find that a single nanowire can show at an absorption peak, a remarkably high absorption cross-section that is more than 50 times the geometrical cross-section. With optimization of the diameter of the single nanowire, the short-circuit current density is 30 times higher than in a bulk solar cell. With such a strong absorption, we predict an apparent efficiency >500% for the single nanowire solar cell. In contrast, we show that an efficient nanowire array solar cell cannot rely on strong absorption just through the absorption peak. Instead, the nanowires need to be packed rather closely to enhance the absorption of the full solar spectrum. At the optimum diameter for the nanowire array, neighboring nanowires compete strongly for absorption of incident photons at the absorption peak, which limits the absorption per nanowire by a factor of 18. As a result, the single InP nanowire is optimized at a diameter of 110 nm while the nanowires in the array are optimized at a considerably larger diameter of 180 nm. Importantly, we show analytically the coupling efficiency of incident light into the fundamental HE11 guided mode and consecutive absorption of the mode in the nanowires. With that analysis, we explain that a single nanowire shows two different absorption pathways—one through coupling into the guided mode and another by coupling into the nanowire through the sidewall. This analytical analysis also shows at which period the neighboring nanowires in an array start to compete for absorption of incident photons.
关键词： III–V semiconductor nanowire,optics modeling,absorption,solar cell
更新于2025-09-19 17:15:36
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A stochastic SPICE model for superconducting nanowire single photon detectors and other nanowire devices
摘要： Superconducting nanowire devices such as the superconducting nanowire single photon detector (SNSPD) or nanocryotron (nTron) have a time-dependent stochasticity that depends on the current flowing through them. When modeling complex circuits made of several such devices (for instance, an array of SNSPDs), the ability to include this randomness can be important for predicting unwanted effects and interactions within the circuit. We present a modification of the model described by Berggren et. al. that allows for the inclusion of this stochasticity into the nanowire device model. We then verify the model against experiment using a tungsten silicide SNSPD, and show that the modified model replicates the stochasticity of the physical device.
关键词： SNSPD,SPICE model,Monte Carlo analysis,superconducting nanowire,nTron,stochasticity
更新于2025-09-19 17:15:36
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[IEEE 2018 IEEE SENSORS - New Delhi, India (2018.10.28-2018.10.31)] 2018 IEEE SENSORS - Contact-Printing of Zinc Oxide Nanowires for Chemical Sensing Applications
摘要： This paper presents a new method for printing zinc oxide (ZnO) nanowires (NWs) and their analysis for chemical sensing applications. High-crystal quality ZnO NWs are synthesized by chemical vapour transport (CVT) technique and directly transferred and aligned on a glass substrate by using contact-printing technique. With an accurate control of the contact-printing parameters such as load and speed over the entire printing process, a highly uniform, dense and well-aligned NWs layers are obtained on the desired substrate over large areas. The validity of the ZnO NWs as chemical sensing material is demonstrated by carrying out both cyclic voltammetry and electrochemical impedance spectroscopic measurements in different pH solutions. Results demonstrate a high stability of ZnO NWs to basic solutions (i.e. pH > 6), which shows their suitability for applications such as sweat or water quality monitoring sensors.
关键词： pH Sensors,Contact-printing,Chemical Sensors,Nanowire Assembly,ZnO Nanowires
更新于2025-09-19 17:15:36
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Hybridizing NiCo2O4 and amorphous NixCoy layered double hydroxides with remarkably improved activity towards the efficient overall water splitting
摘要： Overall water splitting is an attractive technology to produce clean hydrogen and oxygen. In this study, we constructed amorphous NixCoy layered double hydroxide (LDH) hybridized with three-dimensional NiCo2O4 to fabricate core-shell nanowire array on Ni foam (NiCo2O4@NixCoy LDH/NF) as highly efficient electrocatalyst for overall water electrolysis. By tuning the Ni/Co molar ratio in NixCoy LDH, extremely low overpotentials of 193 mV for oxygen evolution reaction (OER) and 115 mV for hydrogen evolution reaction (HER) at a current density of 10 mA cm?2 can be achieved for the NiCo2O4@Ni0.796Co LDH/NF. Detailed investigations verify that the hybrid structure can increase intrinsic activity of the NiCo2O4@Ni0.796Co LDH/NF and enhance the charge-transfer rate. Moreover, a strong electronic interaction between the heterogeneous elements Ni and Co at the interface of the NiCo2O4 and NixCoy LDH might ultimately influence the catalytic performance.
关键词： bifunctional electrocatalyst,nanowire arrays,amorphous material,layered double hydroxide,water splitting
更新于2025-09-19 17:15:36
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Biosensing Using Arrays of Vertical Semiconductor Nanowires: Mechanosensing and Biomarker Detection
摘要： Due to their high aspect ratio and increased surface to foot-print area, arrays of vertical semiconductor nanowires are used in numerous biological applications, such as cell transfection and biosensing. Here we focus on two specific, valuable biosensing approaches that, so far, have received relatively limited attention in terms of their potential capabilities: cellular mechanosensing and lightguiding-induced enhanced fluorescence detection. Although proposed a decade ago, these two applications for using vertical nanowire arrays have only very recently achieved significant breakthroughs, both in terms of understanding their fundamental phenomena, and in the ease of their implementation. We review the status of the field in these areas and describe significant findings and potential future directions.
关键词： mechanosensing,vertical nanowire arrays,fluorescence detection,biosensing,semiconductor nanowires
更新于2025-09-19 17:15:36
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Junction Welding Techniques for Metal Nanowire Network Electrodes
摘要： Transparent conductive electrodes (TCEs), which offer advantages of high electrical conductivity and optical transparency, are essential components of practical high-tech optoelectronics such as touch panels, e-papers, organic light-emitting diodes, and solar cells. Solution-processed Ag nanowires (AgNWs) have been considered as a practical alternative TCE material suitable for industrial-scale mass production. However, the contact resistance at AgNW junctions strongly affects the total sheet resistance of AgNW electrodes. In recent years, various welding techniques for AgNW network electrodes have been developed with the aim of decreasing their sheet resistance while maintaining their optical transmittance. In this paper, we present a review of various welding methods such as thermal-mechanical welding, light welding, chemical welding, and metal-plating welding.
关键词： silver nanowire,transparent conductive electrode,welding,sheet resistance,optical transmittance
更新于2025-09-19 17:15:36
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Ultrathin nanowire based on icosahedral W@Au12 and application as NO gas sensor
摘要： In this study, we used first-principles calculations to investigate the structural and electronic properties of an ultrathin nanowire formed by assembling icosahedral W@Au12 clusters and its application as a NO gas sensor. An ultrathin nanowire with a diameter of about 5.52 ? was produced via the coalescence of icosahedral W@Au12 clusters. The W@Au12-based nanowire exhibited semiconducting properties with a direct band gap. Frequency analysis and molecular dynamics simulations indicated that the nanowire was particularly stable at T = 300 K. The nanowire chemisorbed a NO molecule with moderate adsorption energy, and the N atom in NO bonding with the Au atom was the most stable bond. Analysis of the Boltzmann distribution and transition state demonstrated that the most stable configuration was particularly likely to form. The electronic properties of the W@Au12-based nanowire were changed dramatically by NO adsorption, with a transition from semiconducting to conducting behavior after NO adsorption. However, the adsorption of CO2, CH4, O2, H2, N2, or H2O molecules had little effect on the conductance of the nanowire. Our results indicated that the W@Au12-based nanowire sensor was highly sensitive and selective. The recovery time for the nanowire-based NO sensor was about 12 s at T = 300 K. Therefore, due to its moderate adsorption energy, significant change in the electric conductivity, and very rapid recovery time, we conclude that the W@Au12-based nanowire is a promising gas sensor with high performance at NO detection.
关键词： Icosahedral W@Au12,Assembly,Density functional theory calculation,NO gas sensor,Nanowire
更新于2025-09-19 17:15:36
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Room-temperature H2 gasochromic behavior of Pd-modified MoO3 nanowire labels
摘要： It is great significance to develop an effective eye-readable gas detection technology that would be safe, low-cost, and highly sensitive, serving as a vital complement to traditional H2 sensors. In this work, a class of flexible MoO3 nanowire labels (NWLs) modified with Pd nanoparticles have been successfully developed and studied as eye-readable hydrogen indicators at room-temperature. The nanowire labels turn from white to blue-gray even at a very low concentration (0.1%), where the eye-readable color change takes place in 65 s, and the color changes gradually from white to blue-gray. The reaction of MoO3 nanowire label with hydrogen is of high sensitivity, fast response and time-resolved. The process can be divided into two stages, i.e., fast and slow responses, which are dominated by H2 concentration and intrinsic properties of Pd@MoO3, respectively. The color response is also reversible by annealing under air ambient at 200 °C for 2 h, and selective to hydrogen compared with other flammable gases (i.e., CO, CH3CH2OH, CH3OH). The gasochromic NWLs involve Pd-catalyzed reduction of MoO3 in the presence of hydrogen. They also exhibit the superior advantage of being flexible, which have promises applications in efficient eye-readable hydrogen detection.
关键词： Gasochromic,MoO3,Pd nanoparticles,Nanowire labels,Eye-readable
更新于2025-09-19 17:15:36
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A novel miniature planar gas ionization sensor based on selective growth of ZnO nanowires
摘要： In this study, a novel planar MEMS-based gas ionization sensor based on the field ionization of zinc oxide nanowires is reported. Selective and seedless ZnO nanowires have been grown directly on gold electrodes by low-cost and low-temperature hydrothermal method. Low operating voltage with fast response and recovery times have been achieved for detecting Argon, Helium, Air + %32 RH, Nitrogen, Dry Air, Oxygen, and Carbon dioxide at ambient temperature in atmospheric pressure. Sharp tips of ZnO nanowires reduce the gas breakdown voltage of different gases as shown for Helium and Argon to about 115 V, 85 V respectively due to their local electric field enhancement characteristic. Furthermore, an excellent semi linear response (about 80 V decrease in breakdown voltage) was observed by introducing 250 ppm of NH3 to pure N2 in 4 stages from 0 ppm to 1000 ppm as ammonia gas sensor. In addition, ZnO nanowires protect high conductive Au cathode and anode against sputtering and deformation due to their superior physical, chemical and mechanical properties.
关键词： Nanowire,Planar gas ionization sensor,ZnO,Selective growth,MEMS
更新于2025-09-19 17:15:36
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Growth of Si2Te3/Si heterostructured nanowire and its photoresponse property
摘要： Single-crystalline heterostructured Si2Te3/Si nanowires (H-NWs) were synthesized by using gold nanoclusters as a catalyst. Control of the nanowire structures could be achieved by substrate temperature and growth time. Scanning electron microscopy (SEM) study shows that the as-grown nanowires are composed of two parts: one part has a conical shape with gold catalyst on the top and second part is uniform nanowire. High-resolution transmission microscopy study shows that the H-NWs have a core/shell structure with a silicon nanowire core wrapped by a Si2Te3 shell. The composition of the core-shell structure was confirmed by Energy-dispersive X-ray spectrometry (EDX) measurements. X-ray diffraction (XRD) and Raman spectra confirm the two types of crystal structure of silicon and Si2Te3 in H-NWs. A possible growth mechanism of H-NWs is discussed. The photoresponse property of Si2Te3/Si H-NW is observed under illumination of light. The rise and decay time constants are ~590 ms and ~800 ms, respectively. The unique structure and properties of these silicon-based nanowires of 2D materials are not only interesting for fundamental understanding but also potential building blocks for applications in optoelectronic devices.
关键词： Nanowire,Si2Te3,Core-Shell,Si,Heterostructure,Photoresponse
更新于2025-09-19 17:13:59