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Charge Mobility and Recombination Mechanisms in Tellurium van der Waals Solid
摘要： Trigonal tellurium is a small band gap elemental semiconductor consisting of van der Waals bound one-dimensional helical chains of tellurium atoms. We study the temperature dependence of the charge carrier mobility and recombination pathways in bulk tellurium. Electrons and holes are generated by irradiation of the sample with 3 MeV electrons and detected by time-resolved microwave conductivity measurements. A theoretical model is used to explain the experimental observations for different charge densities and temperatures. Our analysis reveals a high room temperature mobility of cm2V-1s-1. The mobility is thermally deactivated suggesting a band-like transport mechanism. According to our analysis charges predominantly recombine via radiative recombination with a radiative yield close to 98%, even at room temperature. The remaining charges recombine by either trap-assisted (Shockley-Read-Hall) recombination or undergo trapping to deep traps. The high mobility, near unity radiative yield and the possibility of large-scale production of atomic wires by liquid exfoliation make Te of high potential for next-generation nanoelectronic and optoelectronic applications, including far-infrared detectors and lasers.
关键词： recombination mechanisms,charge mobility,optoelectronic applications,Tellurium,van der Waals solid
更新于2025-09-04 15:30:14
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CHARACTERISTICS OF MULTILAYERED METAMATERIAL STRUCTURES EMBEDDED IN FRACTIONAL SPACE FOR TERAHERTZ APPLICATION
摘要： This paper discusses the electromagnetic characteristics of a stratified metamaterial structure placed in fractional dimension space. Reflection and transmission coefficients for plane wave incident on multilayered structure in D-dimensional space are computed. Transfer matrix method is used to study the behaviour of different planer multilayered periodic metamaterial structures. The results are compared for integer and fractal dimensional spaces for both the cases of normal and oblique incidences. Classical results are recovered for integer dimensions. This work provides solution for examining the electromagnetic fields and waves in multilayered structures at fractal interfaces.
关键词： multilayered metamaterial structures,transfer matrix method,electromagnetic characteristics,fractional space,terahertz applications
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - A Compact broadband dual-polarized antenna element for 2G/3G/4G base station applications
摘要： A novel broadband and slant ±45? dual-polarized antenna element with compact structure is presented in this paper for LTE700/CDMA800/GSM900 bands applications. The proposed antenna mainly comprises of two pairs of orthogonal dipoles, four couples of baluns, an octagonal pedestal and two kinds of plastic fasteners. A square aluminum sheet is placed between adjacent dipoles to widen the impedance bandwidth of the antenna. Simulated and measured results show that the proposed antenna element has a wide impedance bandwidth of 31.60% with VSWR < 1.6 from 698 to 960 MHz at both ports. High port-to-port isolation (< ?25 dB) and stable radiation pattern with horizontal half-power beam width (HPBW) of 65?±6.4? are achieved within the whole working band. The antenna is suitable for existing 2G/3G/4G base station applications.
关键词： broadband antenna,dual-polarized antenna,base station applications
更新于2025-09-04 15:30:14
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Dewetting mechanisms and their exploitation for the large-scale fabrication of advanced nanophotonic systems
摘要： Recent progress in submicron- and nano-fabrication technologies has led to the emergence of novel photonic structures such as optical nanoantennas and metasurfaces. Real-life applications of these advanced photonic structures still require substantial improvement of the fabrication processes, in terms of their throughput and cost-effectiveness. Because of its simplicity and effectiveness, dewetting of a thin film has attained increasing attention as a feasible process for improving the scalability and productivity. Here, we provide an overview of the mechanisms and phenomenologies of dewetting to foster an improved fundamental understanding necessary for the optimisation of the dewetting process condition and template design. We then review the strategies demonstrating the use of templated-dewetting for producing well-aligned arrays of submicron- and nanostructures with great control over their size, shape and arrangement. Recent applications of dewetted structures in advanced nanophotonics are reviewed with an emphasis on the exploitation of dewetting mechanisms. Special attention is given to the fabrication of resonant optical nanoantennas and nanophotonic applications in which high repeatability and throughput are important parameters: sensing, colourisation, photovoltaics and nonlinear light frequency conversion. We expect this review to provide a basis for the use of thin-film dewetting to realise the industrial-level fabrication of various practical advanced photonic systems.
关键词： optical nanoantenna,interfacial instability,plasmonics,all-dielectric nanophotonics,nanofabrication,advanced photonic applications,Dewetting,thin film
更新于2025-09-04 15:30:14
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Nanotechnology-Empowered Flexible Printed Wireless Electronics
摘要： In this article, the particular importance of nanotechnology-enabled materials associated with additive manufacturing techniques for the realization of radio-frequency (RF) components and modules for Internet of Things (IoT) and millimeter-wave (mm-wave) applications is discussed. First, a look into the preparation of functional nanomaterial inks for chemical sensing applications and the surface modification processes required for their excellent printability is provided. The focus then shifts toward numerous applications realized through the implementation of the previously listed techniques. These applications discuss origami [morphing/four-dimensional (4-D)-printed] structures, taking advantage of the unique benefits of bending and folding on the printed conductive nanomaterials-based traces on a paper substrate for the fabrication of foldable reconfigurable RF architectures. Then, the synergistic integration of inkjet-printed carbon-based nanomaterials sensors with ultrahigh performance flexible printed antenna structures—utilizing nanoparticles—for the Internet of skins, smart cities, and fifth-generation (5G) applications is described. We then demonstrate the critical importance of nanomaterial-based inks in the development of robust three-dimensional (3-D)-printed RF interconnects with groundbreaking performance, opening the door for the next generation of electronics manufacturing and packaging on virtually every substrate up to frequencies in the sub-THz range.
关键词： origami structures,5G applications,additive manufacturing,millimeter-wave,nanotechnology,Internet of Things,radio-frequency,nanomaterial inks,chemical sensing,flexible electronics
更新于2025-09-04 15:30:14
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Analytical Analysis and Experimental Validation of a Multi-parameter Mach-Zehnder Fiber Optic Interferometric Sensor
摘要： Here we report a simple analytical technique to model a Mach–Zehnder fiber optic interferometric sensors that allow us to predict and calculate via computer simulations parameters that are not easily obtained experimentally. This model was calibrated and compared with experimental data using a 120 mm sensor for measurements of temperature, refractive index and water level. For instance, we were able to calculate the effects on the cladding index caused by the variation of those physical effective parameters. Moreover, this analysis could further our understanding of such sensors and allow us to make predictions about their use in different applications and even their behavior with different sensing lengths.
关键词： optical fiber devices,analytical model,Optical fiber interference,optical fiber applications,optical interferometry
更新于2025-09-04 15:30:14
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Recent Advances and Applications of Near Infrared Spectroscopy for Honey Quality Assessment
摘要： Currently, most of the technologies used to identify honey quality are inefficient and costly. There is a necessity to develop a more effective one for honey quality assessment. Near Infrared Spectroscopy (NIRS) has the potential to be such a technique for its unique characteristics. This study reviews recent advances and applications of NIR spectroscopy in honey authentication domain including constituents, adulteration, brand, botanical origin and geographical origin. It presents a comprehensive using of this technology, with advantages and limitations, in honey quality detection, which offers insights on selecting the most appropriate NIR spectroscopic method for samples presentation, spectral acquisition, spectral pretreatment and modeling. Future research is to be focused on increasing model robustness, developing overall NIR spectroscopic database and a NIR-based integrated technology system on honey quality assessment.
关键词： honey,near infrared spectroscopy,Advances,detection,applications
更新于2025-09-04 15:30:14
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Biosensors in Applications
摘要： These days, especially, the attention is increasing in high technology of sensors designed for various uses in biological matter, biomedicine, drug improvement, security, nutrition safety and ecological monitoring and measuring. The system of these sensors should typically be handy and economical, on condition that quick response with reliability, high sensitivity, and negligible false-reading counts are provided. Biosensors have a multi-disciplinary nature including: biology, chemistry, physics, instrumentation, electronics, optics, and market. The biosensors are detecting devices that combine a transducer with biologically sensitive and selective components. Biosensors can quantity combinations existing in the environment, chemical procedures, food and human body at inexpensive charge in comparison with traditional techniques. This editorial article briefly focuses on an overview of Biosensors, examples and providing a new vista of developments and applications.
关键词： biomedicine,environmental monitoring,Biosensors,food safety,applications
更新于2025-09-04 15:30:14
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Nanostructured Anodic Oxides: Fabrication & Applications
摘要： The special issue of Current Nanoscience entitled “Nanostructured Anodic Oxides: Fabrication & Applications” comprises review papers focused on various aspects of these nanostructures. Nanostructured anodic oxides are awaking high hopes in the research community due to the solutions of emerging problems they offer. Classically, the anodic oxides on aluminum and its alloys are a protective coating, providing improved corrosion resistance [1-5], adhesion of primer to metallic substrate [6] and hardness of the anodized surface [7-10]. However, since two-step self-organized anodization was invented in 1995, allowing to form highly-ordered honey-comb ordering of the nanopores (Fig. 1a), numerous researches have been triggered. On one hand, still new electrolytes, operating conditions and electrolyte additives are being researched, providing new ranges of the applied voltages and consequently new ranges of oxides pore diameter and interpore distance [11-17]. On the other hand, research on anodic aluminum oxide is so mature, that already significant achievements in nanofabrication [18-22] (Figs. 1b-1c), surfaces with tunable wetting angle [23-27], cells culturing platforms [28, 29], biomaterials performance [29], sensing [30, 31], structural color generation [31, 32], photocatalysis [33], renewable energy harvesting [34-36], photonic crystals [37] and plasmonic materials [38] have been reported. Moreover, also other metals are being researched. Numerous achievements in anodization of Ti [39-45] W [46], Zr [47, 48], Cu [49-51], Fe [52], Sn [53], Zn [54] and stainless steel [55] allowed to make progress in renewable energy harvesting [43, 44, 51] (especially in the assembly of dye-sensitized solar cells [44] and photoelectrochemical water splitting [43, 51]), CO2 reduction to hydrocarbons [45], drug delivery systems [41], improvement in biomaterials performance [40] and photocatalysis [46]. Moreover, also intermetallic alloys, like FeAl [56, 57] and bimetallic, layered systems like Al-Ti [58] were anodized in order to form nanoporous oxides with tunable band gap and to ease the nanofabrication, respectively.
关键词： Nanostructured Anodic Oxides,Biomaterials,Anodization,Renewable Energy Harvesting,Photocatalysis,Sensing,Fabrication,Applications,Nanofabrication
更新于2025-09-04 15:30:14
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MULTI-BAND CYLINDRICAL DIELECTRIC RESONATOR ANTENNA USING PERMITTIVITY VARIATION IN AZIMUTH DIRECTION
摘要： A novel multi-band cylindrical dielectric resonator antenna (CDRA) using microwave laminates with permittivity variation in azimuth direction fed by coaxial probe is proposed in this paper. The proposed structures are constructed using di?erent materials having di?erent permittivities in azimuth direction in cylindrical dielectric resonator (DR). In order to determine the performance of various design parameters on resonance frequency and bandwidth, parametric studies have been performed. The operating band can be scaled up or down by adjusting the design parameters. Dual-band and triple-band CDRAs have been fabricated using commercially available microwave laminates to validate the simulation results. For each case, the input re?ection coe?cient, radiation pattern and antenna gain are simulated and measured. Good agreement between simulated and measured results has been observed. The proposed antennas may be suitable for WLAN applications.
关键词： WLAN applications,coaxial probe,multi-band,azimuth direction,permittivity variation,cylindrical dielectric resonator antenna
更新于2025-09-04 15:30:14