Showing papers in "Transactions on Electrical and Electronic Materials in 2020"
TL;DR: In this article, the effect of nanoparticles on the optimized geometrical parameters and electronic properties of poly-methylmethacrylate has been investigated for first time, the optimization parameters included both bonds angles and bonds length.
Abstract: In this paper, the effect of (Al2O3, ZrO2, Ag, Al2O3-Ag, ZrO2-Ag) nanoparticles on the optimized geometrical parameters and electronic properties of poly-methylmethacrylate has been investigated for first time. The optimization parameters included both bonds angles and bonds length. The electronic properties included the (lower unoccupied molecular orbital energy (ELUMO), high occupied molecular orbital energy (EHOMO), energy gap (Eg), ionization potential (IE), electron affinity (EA), electronegativity (χ), electrochemical hardness H, electronic softness S total energy, total dipole moment and Average polarizability). The results showed that the addition of nanoparticles has a direct impact on all the properties of the molecules studied. The increase in the number of atoms leads to decreased energy gap from 7.0329 to 2.7689 eV. The ionization potential and electron affinity decrease with increasing of atoms number for structures. The produced nanocomposites have different applications in many fields such as: gas sensors, solar cells, diodes, UV shielding, lasers, optoelectronics, medical application, dental filling…etc.
57 citations
TL;DR: In this article, the structural, optical and electrical properties of polyvinyl alcohol (PVA)-polyethylene oxide (PEO) blend doped with tin dioxide (SnO2) nanocomposites have been investigated for flexible electrical and optical applications.
Abstract: Fabrication of polyvinyl alcohol (PVA)–polyethylene oxide (PEO) blend doped with tin dioxide (SnO2) nanocomposites has been investigated for flexible electrical and optical applications. The prepared nanocomposites have low cost, lightweight, flexible, high corrosion resistance, good optical and electrical properties. These properties of fabricated nanocomposites make it useful for different optoelectronics applications such as: sensors, solar cells, transistors, diodes, capacitors, energy storage etc. The structural, optical and electrical properties of (PVA–PEO–SnO2) nanocomposites have been studied. The experimental results of optical properties for (PVA–PEO–SnO2) nanocomposites showed that the nanocomposites have higher absorbance in UV region at wavelength range (200–280) nm. This behavior makes the nanocomposites may be used for optoelectronics applications. The absorbance, absorption coefficient, extinction coefficient, refractive index, real and imaginary dielectric constants and optical conductivity of polymer blend are increased with the increase in SnO2 nanoparticles concentrations while the transmittance and energy band gap are decreased with the increase in SnO2 nanoparticles concentrations. The decrease in energy band gap is useful for different optoelectronics devices industries. Also, the results showed that the dielectric constant and dielectric loss decrease while the conductivity increases with the increase in frequency. The dielectric constant, dielectric loss and conductivity are increased with the increase in SnO2 nanoparticles concentrations. The electrical properties showed that the (PVA–PEO–SnO2) nanocomposites have good dielectric parameters which it may be used for different electronics applications.
56 citations
TL;DR: In this paper, a theoretical study was conducted to investigate the electronic structure and optimized geometry for pure PMMA and PMMA doped with ZrO2, Al2O3 and Pt nanoparticles for electronics devices.
Abstract: This work reports a theoretical study to investigate the electronic structure and optimized geometry for pure PMMA and PMMA doped with ZrO2, Al2O3 and Pt nanoparticles for electronics devices. The studied structures are initially relaxed by employing the hybrid functional three parameter Lee–Yang–Parr B3LYP density functional theory at Gaussian 09 package of programs and Gaussian view 5.0.8 program. The PMMA is origin molecule before adding nanoparticles, also this work includes calculations of the electronic properties which contain total energy, energy of highest occupied molecular orbital, energy of lowest unoccupied molecular orbital, energy gap, ionization potential, electronic affinity, hardness, softness, electronegativity and electrophilic index. The geometrical optimization of PMMA has been found in good agreement with the experimental data due to its relaxed geometrical parameters. The electronic variables, such as, IE, EA, χ, S, H and ω are computed by the orbital vertical (Koopmans theorem), the nanocomposites studied need small energy to become cation due to ionization potential is smaller than original PMMA, but the electronic affinity are larger than the original PMMA. So, the hardness for nanocomposites was lowering values as compared with PMMA, therefore all the new molecules are softer, and this reduces the resistance of a species to lose electrons, and the total energy of the studied PMMA was decreased with added nanoparticles to the pure PMMA, total energy is a reflection of, binding energy of each sheet. The results showed that the nanoparticles added to PMMA reduces the energy gap. All nanoparticles constructed in this work have energy gap lower than that of original PMMA and the (PMMA–ZrO2–Pt) nanocomposites have the lowest value of energy gap. These results refer to construct new structures with new electronic properties to use it for modern electronics fields.
52 citations
Abstract: A strong conductive and magnetically strengthened microwave shielding hybrid epoxy composite was prepared and analyzed. The principal aim of this research work was to prepare a high stable microwave shielding hybrid epoxy composite with surface modified MWCNTs and iron(III) oxide nano particles. The surface-modification on these reinforcements favour the composites been retained their magnetic and electrical conductivity even in elevated temperatures 100 °C and 200 °C and frequency up to 50 GHz. The kenaf fibre, MWCNTs and iron(III) oxide particles were surface-modified by APTMS for effective protection of reinforcements. The composites were prepared using hand layup method. The additions of silane-treated kenaf fibre and MWCNTs with iron(III) oxide into epoxy resin improved the mechanical properties, the same has been discussed in the previous article by the author. The silane surface-modified composites gave unaltered dielectric constant and microwave shielding behaviour in elevated temperatures. The acquisition of residual magnetism remains same as room temperature and 200 °C. The maximum relative magnetic permeability of 1.2 and dielectric constant of 4.0 was observed for composite designation ‘E’ in room temperature. Similarly maximum EM wave attenuation of 44 dB was achieved in J band frequency at 200 °C. These high stable microwave shielding composite materials are capable of serving as shielding materials in electronic communication gadgets, radar and microwave shielding helmets.
40 citations
TL;DR: This paper explains QCA based combinational circuit design; such as half-adder and full-adder, by only one uniform layer of cells, using a novel XOR gate.
Abstract: Quantum-dot Cellular Automata (QCA) is a new technology for designing digital circuits in Nanoscale. This technology utilizes quantum dots rather than diodes and transistors. QCA supplies a new computation platform, where binary data can be represented by polarized cells, which can define by the electron’s configurations inside the cell. This paper explains QCA based combinational circuit design; such as half-adder and full-adder, by only one uniform layer of cells. The proposed design is accomplished using a novel XOR gate. The proposed XOR gate has a 50% speed improvement and 35% reduction in the number of cells needed over the best reported XOR. The results of QCADesigner software show that the proposed designs have less complexity and less power consumption than previous designs.
38 citations
TL;DR: In this article, the development of field effect mobility as well as the stability enhancement has been comprehensively reviewed in thin-film transistors (TFTs) for the high-end device applications.
Abstract: Oxide materials are one of the most advanced key technology in the thin film transistors (TFTs) for the high-end of device applications. Amorphous oxide semiconductors (AOSs) have leading technique for flat panel display, active matrix organic light emitting display, active matrix liquid crystal display as well as thin film electronic devices due to their excellent electrical characteristics, such as field effect mobility (μFE), subthreshold swing (SS) and threshold voltage (Vth). Researchers from various fields have studied and considered ways to improve µFE of AOS TFT, which has been studied for 16 years since 2004. Since 2004, mobility has been increased by using various methods, such as designing novel amorphous oxide materials, changing device structures, or adopting new post-treatment. The development of field effect mobility as well as the stability enhancement has been comprehensively reviewed in this report.
34 citations
TL;DR: In this paper, a dual source n-type vertical tunnel field effect transistor (VTFET) is proposed and investigated using technology aided design simulation, which has a dispersal of the source channel drain in the vertical direction to enhance the scalability of the simulated device.
Abstract: An optimally designed Dual Source Vertical Tunnel Field Effect Transistors is proposed and investigated using technology computer aided design simulation. The vertical tunnel FET have dispersal of source channel drain in the vertical direction which will enhance the scalability of the simulated device. The benefit of the TFET is switching mechanism which is done by quantum tunnelling method through a barrier instead of thermionic emission over the barrier as that of conventional MOSFETs. The key of this paper, we have developed two-dimensional model of single drain with dual source n-type vertical tunnel field effect transistor. Further introduction to an ultra-thin channel among the drain and gate region will makes aggressive improvement in the numerical simulations of minimum threshold voltage (VT) of 0.15 V and average subthreshold slope of 3.47 mV/decade. The variation effect in the channel thickness, source height, drain doping, source doping, temperature and work function has been simulated and examined by 2D silvaco TCAD tool. High ON current and low OFF current is recorded as 1.74 × 10−4 A/µm and 6.92 × 10−13 A/µm respectively with ION/IOFF current ratio in order of 108 to 109.
31 citations
TL;DR: In this article, the authors present an attempt to take the scaling up to 3-nm and beyond by combining non-silicon channel material such as Ge, InGaAs, or 2D materials with nanosheet, which will improve the functionality of the device while going down in the technology node.
Abstract: To overcome scaling issues such as controlling gate leakage, drain induced barrier lowering, higher subthreshold conduction, polysilicon gate depletion, and other short channel effects various engineering proposed. The gate dielectric, metal work function, and device structural engineering enabled the semiconductor industry to make a transition from the conventional planar MOSFET towards a revolutionary 3D tri-gate structure called FinFET. FinFET is one of the fundamental invention in the semiconductor industry, which replaced the planar CMOS technology around 22 nm technology. By following Moore’s law, it accelerated the scaling to 7 nm, but at 5 nm, in the same way, GAAFET replaced FinFET due to technological hurdles. Nanosheet, which is one type of GAAFET are in the recent trend. But researchers are trying to explore the possibilities to continue the miniaturization beyond 3 nm by combining the effect of non-silicon channel material such as Ge, InGaAs, or 2D materials with nanosheet, which will improve the functionality of the device while going down in the technology node. In this survey, an attempt has been made for the structure present till 7 nm process. Also, a few new proposals in research to take the scaling up to 3 nm and beyond are included. The future innovations may put an intercept on the slowing down of Moore’s law, and bring the miniaturization back in the track.
24 citations
TL;DR: In this paper, materials and devices engineering are described for achieving stability and higher power conversion efficiency in perovskite solar cells, which is expected to be helpful to achieve high efficiency PSCs.
Abstract: Since the first report on 9.7% efficient solid-state perovskite solar cell (PSC) in 2012, perovskite photovoltaics received tremendous attentions. Efforts to increase power conversion efficiency (PCE) have been continuously made. As a result, a record PCE of 25.2% was certified in 2019, which surpassed those achieved from the conventional solar cells based on CIGS and CdTe. The superb photovoltaic performance of PSC is related to the defect-tolerant property, the long carrier lifetime, the long diffusion length of photo-generated carriers, and the high absorption coefficient. In this review, materials and devices engineering are described for achieving stability and higher PCE in PSCs. From the practical point of view, key technologies for materials, coating, and device fabrication are described, which is expected to be helpful to achieve high efficiency PSCs. Moreover, interfacial engineering methodologies toward hysteresis-less and stable PSCs are also presented to give insight into better understanding ion migration and recombination in PSCs.
20 citations
TL;DR: In this paper, the authors compare all the generations which photovoltaic cells (PVC) have undergone and the recent advancements in this area and the results of this research study will be fruitful for researchers working in this direction.
Abstract: With the technology and innovation rising at its peak, the demand for energy has increased exponentially To cater this, researchers are persistently exploring ways to fulfil this deficit between demand and supply One of the feasible solutions is the use of energy from renewable resources such as Solar Energy due to its abundance availability and easy accessibility Seeing it’s trans formative potential to address growing concerns about environment, pollution and sustainable energy integration, there is an intemperate research going on in developing highly efficient Photovoltaic Cells (PVC) The PVC’s are effectuated to convert solar energy from the sunlight directly to electrical energy Furthermore, the PVC has gone through various generations with the aim to optimise its cost/watt of delivered solar electricity and efficiency of solar cell This paper is an effort to compare all the generations which PVC has undergone and the recent advancements in this area The results of this research study will be fruitful for researchers working in this direction
20 citations
TL;DR: In this paper, the temperature dependence of DC and AC conductivities was fitted with Arrhenius equation and activation energies at different temperature ranges were calculated to understand the conduction process.
Abstract: Ceramics of (Bi1−xGdxFeO3) [x = 0.5, 0.6 and 0.7] were synthesized through mixed oxide method. Structural studies of the ceramics were done using X-ray diffraction technique. At high frequency, nearly flat response in the dielectric constant and dielectric loss with temperature up to 200 °C were observed. Dielectric constant found to increase with decrease in Gadolinium concentration. Frequency dependent electrical data analysis at different temperatures suggested a temperature dependent non-Debye type relaxation process in the ceramics. Frequency dependence AC conductivity at different temperatures obeyed Jonscher’s universal power law. The temperature dependence of DC and AC conductivity was fitted with Arrhenius equation. The activation energies at different temperature ranges were calculated to understand the conduction process.
TL;DR: In this article, the authors reviewed leakage current effect based on local area conditions and different techniques used to measure leakage current in lab and at field, special focus on online leakage current monitoring.
Abstract: High voltage outdoor insulator plays a pivotal role in safety and reliability of power transmission system.Contamination severely influences the performance of outdoor insulator. To asses contamination severity on insulator surface and to predict flashovers, leakage current monitoring is required. The amount of leakage current flowing on the surface of insulator indicates insulation safety. Increase in leakage current generates high voltage peaks at insulator dead ends. The voltage may be as high as 1000–5000 volts, mainly depends on certain weather conditions, results in enormous amount of power losses and threat to public safety. The insulator performance depends on amount and type of pollution and wetting mechanism. Leakage current is important tool to investigate insulator electrical surface activity. The scope of this paper is to review leakage current effect based on local area conditions. Leakage current importance for insulators and different techniques used to measure leakage current in lab and at field, special focus on online leakage current monitoring.
TL;DR: In this paper, the rear emitter silicon heterojunction solar cells of a p-type on the rear side have garnered increasing attention for various reasons, such as the optical properties of the front side's transparent conductive oxide (TCO) layer can be emphasized owing to a lateral transport on the cells, and majority of the carriers are affirmed through a Si substrate.
Abstract: This inclusive study provides detailed information regarding the evolution of rear emitter silicon heterojunction solar cells. Silicon heterojunction (SHJ) solar cells of a p-type on the rear side have garnered increasing attention for various reasons. First, owing to a limitation of the p-type hydrogenated amorphous silicon layer, further optimization relative to an n-type cannot be achieved, and an accumulation of electrons at the front side allows utilizing an n-type wafer to affirm a lateral current transport. Second, better thin n-type nanocrystalline silicon (oxide) contact layers compared to p-type wafers are grown, and allow greater freedom in the structural design. The optical properties of the front side’s transparent conductive oxide (TCO) layer can be emphasized owing to a lateral transport on the cells, and majority of the carriers are affirmed through a Si substrate. In the instance of a rear emitter, the TCO layer is in relief to an adjustment inhibiting the contact resistance between TCO/a-Si:H(p). The fabrication was done in such a manner of SHJ rear emitter solar cells that they achieve greater optimization and overall efficiency of 23.46%.
TL;DR: In this paper, five types of titanium dioxide (TiO2) nanocrystalline sol-gel paste with three different types of dye have been prepared and layered on Indium Tin-Oxide coated glass to fabricate dye-sensitized solar cells.
Abstract: In this research work five types of titanium dioxide (TiO2) nanocrystalline sol–gel paste with three different types of dye have been prepared and layered on Indium Tin-Oxide coated glass to fabricate dye-sensitized solar cells. The dyes extracted from Malabar spinach seeds (MSS), Red spinach and Pomegranate burgs were used as photosensitizer. All the electrical properties investigated by LCR meter were found to be improved with MSS dye but sample with 0.3 M HNO3 (sample-3) exhibited the best electrical properties. The current–voltage characteristics for all the samples showed ideal behavior. The highest maximum power of 176.3 μW and efficiency of 9.23% was found for sample-3 with MSS dye. The smallest crystallite size was found to be 28.82 nm for sample-3 by XRD data which was also supported by the SEM results. Thus, this study reveals that MSS dye has the great potential to be used as photosensitizer.
TL;DR: In this article, the surface modification for light trapping based on the Si solar cell application is reported, where front-side texturing and rear-side polishing are used to reduce the thickness of the Si wafer.
Abstract: Reducing crystalline silicon (c-Si) wafer thickness is an effective method to reduce the fabrication cost as it constitutes a major portion of the photovoltaic module cost. However, the open-circuit voltage and fill factor depend on the wafer thickness; further, the short-circuit current density (JSC), affects the device performance negatively. Therefore, light trapping is vital for increasing the JSC of Si solar cells. Consequently, it is essential for improving the conversion efficiency of the solar cell and reduce its production cost by decreasing the wafer thickness. It can be assumed that the thickness of the Si wafer will gradually achieve a minimum value of ~ 100 μm in the future. Therefore, reducing the as-cut wafer thickness will result in a more efficient use of Si. This paper reports the surface modification for light trapping based on the Si solar cell application. Additionally, we introduce methods for surface modification, such as front-side texturing and rear-side polishing.
TL;DR: In this article, surface potential and drain current models for a physically based double halo metal-oxide-semiconductor-field effect transistor (MOSFET) are reported, where the conventional silicon-dioxide (SiO2) material is replaced with a promising high-k dielectric material hafnium oxide (HfO2).
Abstract: Surface potential and drain current models for a physically based double halo metal–oxide–semiconductor-field-effect-transistor (MOSFET) are reported. The proposed models have been established in sub-threshold mode of MOSFET operation. The depletion layer depth used in the pseudo two dimensional Poisson’s equation comprises the effect of two symmetrical pocket implantations at both the ends of the channel region. In this effort, improvement in the investigation is brought in by taking lateral asymmetric channel owing to non-uniform doping. The conventional silicon-dioxide (SiO2) material is replaced with a promising high-k dielectric material hafnium oxide (HfO2) to analyze the surface potential and drain current models. Analytical results have been compared using Synopsys technology computer aided design (TCAD). Excellent conformities between the analytical models and simulations are observed.
TL;DR: In this paper, the authors presented CaTiO3 as an important negative temperature coefficient resistance (NTCR) thermistor material, and two routes were adopted such as solid state reaction and high energy ball milling (HEBM) for comparative analysis.
Abstract: Present research presents CaTiO3 as an important negative temperature coefficient resistance (NTCR) thermistor material. Two routes were adopted such as solid state reaction and high energy ball milling (HEBM) for comparative analysis. X-ray diffraction (XRD), and Steinhart–Hart equation used for characterization of material formation and thermistor property. XRD pattern shows single phase orthorhombic symmetry or both samples. Electrical resistance found by LCR meter shows about NTCR behaviour and Steinhart–Hart model provides information for its suitability towards thermistor industry. To know the faster response nature time domain analysis performed on both samples. To the best knowledge, there are not much data available on properties of CaTiO3 as thermistor based temperature sensor material, which lead this research work. Enhanced sensing behaviour observed in CaTiO3 processed through HEBM. Both the samples signifies their strong potential in thermistor industry with sensitivity in the range of 4000–6700 K with exponential electrical resistance change in the specified temperature range.
TL;DR: In this article, the thickness of window and absorber layers, one of the crucial factors that affect the solar cell performance, is tuned for ZnO/CdS/cdTe system.
Abstract: CdTe based solar cells with high efficiency alternative to solar cells from elemental semiconductors is an important work carried out over the decades. However, the research has not yet yielded the highest possible efficiency with CdTe absorber. Selection of suitable window layer and optimizing the thickness of the different layers is still a quest in researchers. Numerical simulation of the different material combinations can speed up the research work. In this regard, numerical simulation is an essential tool to find the optimized structure for the enhanced device performance. In the present work, the thicknesses of window and absorber layers, one of the crucial factors that affect the solar cell performance, are tuned for ZnO/CdS/CdTe system. In case of CdS/CdTe solar cells, spectral loss created by CdS lowers the cell efficiency. Concept of bilayer window is useful to minimize the loss at window layer. Hence the ZnO/CdS bilayer window is adopted and demonstrated that the cell efficiency can be increased up to 17.66% with current density of 28.4 mA/cm2 and 73.7% fill factor.
TL;DR: In this article, different material selection techniques like Ashby, TOPSIS and VIKOR have been used to select the best dielectric material for RF-MEMS switches with low power consumption.
Abstract: In this paper, different material selection techniques like Ashby, TOPSIS and VIKOR have been used to select the best dielectric material for RF-MEMS switches with low power consumption. These methods help in choosing the optimum material from the available pool of materials. The dielectric material should be selected such that RF-MEMS capacitive switch should have good RF response, high thermal conductivity, low thermal coefficient of expansion, and low leakage current. For this purpose, the concerned material indices should have high value of relative permittivity, high value of electrical resistivity, low value of thermal coefficient of expansion, and high value of thermal conductivity. The presence of trade-offs led to no conclusive selection in case of Ashby’s method. Following Ashby’s method, TOPSIS and VIKOR method were used to select the optimum material. The end results suggest that TiO2 is the most suitable materials for shunt capacitive RF-MEMS switches.
TL;DR: In this article, the authors highlight investigation of various failures of suspension type porcelain insulators, influencing factors responsible for degradation in lifetime and deterioration of suspension types of insulators.
Abstract: Reliability of a power system is generally designated as a measure of the ability of the system to provide customers with adequate and constant supply. Power system failure have adverse effects and become a great concern for important large scale industries in South Korea such as semiconductors, steel and chemicals which require a high quality, stable power supply. In South Korea, nearly 80% of transmission system failures are caused by either natural eventualities such as lightning strikes or failure of insulators. Ageing assets pose significant challenges for utilities. Moisture with high temperature, fluctuation in temperature, contamination and electric stress accelerates aging in suspension insulators. The primary goal for the utility is to utilize the full life of an asset, but ageing increases the probability of deterioration and failure of equipment. The average age of vital assets, is estimated to be more than 35 years. In South Korea near about 1,223,538 porcelain insulators are reported to be in functional state. Among them only 65.19% of insulators are reported to be in operative state over 35 years. Insulators demand only 5–8% of installation costs. However, it demands more than 50% of maintenance costs. Thus, deterioration of insulator enhances capital expenditure and decrease returns on the asset base. Therefore, insulators should possess excellent electrical aging resistance to prevent deterioration of insulators. Korea Electric Power Corporation (KEPCO), largest power generation and distribution utility in South Korea utilize porcelain for almost all suspension insulators employed in transmission lines. Porcelain insulators are usually employed in transmission system as they are cost-effective and possess near about 30 to 60 years of lifespan. Lifetime evaluation of porcelain insulators in overhead transmission line is absolutely challenging, owing to aging process. This work highlights investigation of various failures of suspension type porcelain insulators, influencing factors responsible for degradation in lifetime and deterioration of suspension type insulators, various laboratory test methods available for evaluation of insulators employed in overhead transmission lines.
TL;DR: In this article, the Ashby method is used to systematically identify the best suited contact materials by translating the requirements of FMS contacts into objectives and constraints and deriving material indices for each objective.
Abstract: Medium and high voltage DC grids are increasingly proposed for terrestrial, shipboard and aircraft power systems. However, multi terminal DC networks can only be realized with the development of a DC circuit breaker. Due to the difficulty in breaking DC currents, hybrid circuit breakers—which consist of a non-arcing fast mechanical disconnect switch (FMS) in parallel with a solid state switch—is the most promising solution. The stresses experienced by the electric contacts of FMS are different from those of AC and low voltage DC breakers and disconnect switches. The choice of contact material has a significant impact on the performance of the DC circuit breaker. The Ashby method is used to systematically identify the best suited contact materials by translating the requirements of FMS contacts into objectives and constraints and deriving material indices for each objective. Minimizing power loss, wear and overheating of contacts are identified as the key objectives. The results suggest that copper-based alloys and compounds are more suitable than silver based alloys and compounds and other contact materials.
TL;DR: In this paper, the design and simulation of RF MEMS Shunt type switch having non-uniform meanders has been discussed and optimized and done various electromechanical and RF performance analysis in the COMSOL multiphysics and HFSS tools.
Abstract: This paper deals with design and simulation of RF MEMS Shunt type switch having non-uniform meanders. The device is optimized and done various electromechanical and RF performance analysis in the COMSOL multiphysics and HFSS tools. By varying the thickness of beam, gap and changing the beam materials such as Gold, Copper, Nickel, we done simulation and calculation of spring constant, pull-in voltage, capacitance analysis of the proposed switch. Out of all these different materials, Gold is best by its material properties. The pull-in voltage of proposed switch is 16.9 V, the switch have fast switching time i.e. 1.2 µs. The capacitance analysis like Up state and down state capacitance of the proposed switch is 7.46 fF and 1.25 pF. The RF-Performance of the proposed switch exhibits at low frequencies (2–12 GHz). The return and insertion loss are carried out by proposed switch is − 41.55 dB, − 0.0865 dB respectively. The switch having good isolation is − 47.70 dB at 5 GHz. The proposed shunt type switch is used for low frequencies such as microphones, radar and satellite applications.
TL;DR: In this paper, the degradation of low voltage photovoltaic DC cables under thermal stress was studied by measuring the dielectric properties; complex permittivity, tanδ with the change in frequency and decay and return voltage slopes using extended voltage response method.
Abstract: The output power of the photovoltaic system is heavily dependent on the low voltage (LV) DC cables which are exposed to multiple stresses such as climatic, mechanical, electrical, and thermal stress, hence makes them more exposed to aging as compared to other components in the system. Accordingly, it is essential to monitor the state and know the real cause of the insulation degradation of the cable. The physio-chemical changes inside the insulation during service is attributed to the thermal stress, which the cable has to endure constantly. Traditionally, destructive test techniques have been adopted to study the aging phenomenon in the cable insulation, making them unsuitable for on-line condition monitoring. This research work has been aimed to study the degradation in LV photovoltaic DC cables under thermal stress by measuring the dielectric properties; complex permittivity, tanδ with the change in frequency and decay and return voltage slopes using extended voltage response method. The non-destructive diagnostic methods used are based on the phenomenon of polarization and conduction in the insulation material. The noteworthy change in the values of the imaginary part of permittivity, tanδ at low frequencies, and the overall decrease in the values of return voltage slope showed the change in the structure of the polymer matrix under the stress which was related to the cross-linking based chemical reactions. The results show that the techniques can be adopted for the on-line condition monitoring of the cable for the PV system and the dielectric parameters can be used to study the chemical and physical changes happening inside the material effectively.
TL;DR: In this article, the results of X-ray diffraction analysis shown that the doped films are polycrystalline, and the average crystallite size of the synthesized thin films was found to be dependent on the ZnO concentration.
Abstract: Rhombohedral structure of chromium oxide (Cr2O3) thin-film doped hexagonal zinc oxide (ZnO) nanoparticles have been prepared using pulsed laser deposition technique at a different weight percent of ZnO from 0 to 9 wt%. The results of X-ray diffraction analysis shown that the doped films are polycrystalline, and the average crystallite size of the synthesized thin films is found to be dependent on the ZnO concentration. The surface morphology of the prepared thin films was characterized by atomic force microscopy. The optical properties are investigated using ultraviolet–visible light (UV–Vis) absorption spectroscopy. The optical bandgap ranged from 2.45 to 2.68 eV, showing the shift towards longer-wavelength compared to bulk Cr2O3 (~ 3 eV). The sensitivity, response, and recovery times of the sensor towards nitrogen dioxide (NO2) gas were studied and discussed. The sensitivity increase with increasing the doping concentration, and started to decrease when ZnO concentrations reach 7 wt%. The optimal ZnO concentrations for NO2 gas sensitivity is 5 wt%, which attain maximum sensitivity of 87.5% at temperature of 523 K.
TL;DR: In this paper, a modified sol-gel technique has been used to prepare the Nb doped CCTO ceramic thin film and X-ray diffraction of the prepared film confirms the cubic perovskite structure of the material.
Abstract: Modified sol–gel technique has been used to prepare the Nb doped CCTO ceramic thin film. X-ray diffraction of the prepared film confirms the cubic perovskite structure of the material. The micrographs obtained from the Scanning Electron Microscope reveal plenty of rods like microstructure within the scan area. This is being reported for the first time in the studied film. Dielectric constant is measured with the frequency range 100 Hz–1 MHz and it is observed that, with increase in frequency the dielectric constant decreases. Further, it is also observed that, the rate of decrease of er with frequencies increases with increasing temperature. The dielectric loss of the material decreases with increasing frequency and at low frequency region the dielectric loss increases with increase in temperature. The studied material shows relaxor behaviour (γ = 1.87) and is confirmed by peaks broadening at low frequency with increasing temperature and the peaks shift to low frequency region with decreasing temperature. The broad band spectrum of high dielectric constant is seen over the studied temperature range. This relaxation behaviour arises due to space charge polarization. The absorption and transmittance nature of the film is also presented and the calculated value of energy band gap is found to be 2.52 eV.
TL;DR: In this paper, the impact of gadolinium substitution in the crystal structure, morphological behavior and electrical properties of multiferroic Gd doped BiFeO3 and PbTiO3 (PT) samples was studied by adopting the solid state reaction process.
Abstract: Multiferroic gadolinium (Gd) doped BiFeO3 (BFO) and PbTiO3 (PT) samples [(Pb1−xBi0.5xGd0.5x)(FexTi1−x)O3] with x = 0.1, 0.3, 0.5 and 0.7 are formulated by adopting the solid state reaction process. The impact of gadolinium substitution in the crystal structure, morphological behavior and electrical properties has been studied. By altering the Gd concentration in the solid solution a change in the structure is observed that is from tetragonal to rhombohedral. The size of the grain in the compounds reduces as a result of enrich in gadolinium content of the furnished sample. The subsidence of lead minimizes the toxic behavior of the material with significant improvements in dielectric response of gadolinium modified BiFeO3–PbTiO3 synthesized system. From the impedance study, the material presents negative temperature coefficient of resistance characteristics and the impedance is due to the presence of grain and grain boundary effect inside the materials. It is realized that the remnant polarization decreases and frequency dependent ac conductivity increases with the concentration of gadolinium in the electronic system. From conductivity study, the equipped electronic materials show non-exponential type of conductivity relaxation.
TL;DR: In this article, the double 2-DEG was used to improve the linearity of the DG MOSHEMT and achieved a nearly ideal sub-threshold slope and higher Ion/Ioff ratio.
Abstract: In this work, AlGaN/GaN based DG MOSHEMT is designed at 0.8 µm gate length with Al2O3 gate dielectric. The key device performance parameter such as gm, AV, fT, and fmax has been investigated using 2D Mixed-Mode Sentaurus TCAD device simulation. The use of the double heterostructure helps to achieve higher on-current. We observe a double hump type feature in transconductance which is attributed to occurrence of the double 2-DEG, resulting in better device linearity. Further, the double gate structure is responsible for nearly ideal subthreshold slope (~ 59.94 mV/dec) and higher Ion/Ioff ratio (> 1016). Moreover, the device offers comparable cut-off frequency (19.25 GHz) and maximum-oscillation frequency (66.95 GHz) to the existing Al2O3/AlGaN/GaN based SG MOSHEMT alongwith tremendous improvement in terms of intrinsic gain (~ 76 dB). Furthermore, enhancement of the device performance (fT = 122.44 GHz and fmax = 163.07 GHz) is achieved by scaling down the gate length from 0.8 µm to 100 nm. These results indicate that Al2O3/AlGaN/GaN based DG MOSHEMT can be possible alternative for millimeter and microwave frequency applications.
TL;DR: An efficient way to reduce the power consumption of sensor nodes in an IoT ecosystem by using the deep sleep mode of NodeMCU and transmitted humidity data wirelessly to Google Sheets via a nodeMCU Wi-Fi module.
Abstract: In this paper, we provided an efficient way to reduce the power consumption of sensor nodes in an IoT ecosystem. In many cases, IoT objects are battery powered and need to be energy efficient as the most important requirement in order to have a stable operation over long periods of time. The deep sleep mode is used for low power monitoring of NodeMCU. Commercial humidity sensors normally sleep and wake up once an hour to measure soil humidity. The measured humidity data was transmitted wirelessly to Google Sheets via a NodeMCU Wi-Fi module. The user can check the humidity of the soil by referring to the transmitted data values. The power consumption was reduced by about 83% for 1 h than compared to the always awake mode.
TL;DR: In this paper, a coplanar waveguide fed antenna with inverted six shaped configuration having wide band attributes, proposed and designed on a FR4 substrate is presented. And the dimensions of the designed antenna are 54 mm × 38 mm.
Abstract: In this paper a novel coplanar waveguide fed antenna with inverted six shaped configuration having wide band attributes, proposed and designed on a FR4 substrate. The dimensions of the designed antenna are 54 mm × 38 mm. Few rounded corners system is used in this design to improve the bandwidth and gain of proposed antenna. Being a simple antenna, it makes it extremely reasonable for the future generation of Internet of Tings applications. A well-ordered outline process is completed to get an upgraded plan for good impedance matching in the required band. The Reflection coefficients along with the current densities at various phases of the design process are discussed and analyzed to get a decent understanding into the proposed antenna plan. The proposed antenna exhibits stable radiation, having low back lobes and low cross polarization and having greatest gain 6 dBi.
TL;DR: An overview of the different solar cell characterization techniques is presented in this article, where simulations are carried out for these characterization techniques to study the behavior of the P3HT:PCBM based OSC in which silver NPs are incorporated in the active layer.
Abstract: Solar cells are a potential option to meet the growing energy requirements of humans. Organic solar cells (OSCs) represent a class of solar cells that is a part of the third generation solar cell technology. The quest for obtaining enhanced OSC efficiencies has led to the incorporation of metallic nanoparticles (NPs) in the OSCs. Metallic NPs increase the incident light absorption instances, thus increasing the obtainable cell efficiencies. Different parameters and factors need to be considered for obtaining the optimum NP specifications. Investigations of the mechanism of light absorption after the introduction of NPs in the OSC are critical. Hence theoretical simulations for such OSCs are important. An overview of the different solar cell characterization techniques is presented in this paper. Simulations are carried out for these characterization techniques to study the behavior of the P3HT:PCBM based OSC in which silver NPs are incorporated in the active layer. The simulations are carried out for the cell structure in the presence of different non-ideality factors. The non-idealities include mobility limitations, presence of traps, recombination losses, low generation, presence of non-ideal values of series and shunt resistances, the effect of doping, etc. The simulated characterization techniques can be utilized for the performance study and parameter extraction of these NP incorporated OSCs.