Electrode Width Research Articles

An Investigation of Internal Quantum Efficiency of Bifacial Interdigitated Back Contact (IBC) Crystalline Silicon Solar Cell

In this article, we investigated the internal quantum efficiency (IQE) properties of n-type bifacial interdigitated back contact crystalline silicon solar cells using an IQE mapping system. In the cell structure, high and low IQE values were observed above the emitter and back surface field (BSF) regions. The IQE values above the BSF busbar were drastically reduced due to electrical shading loss. Line scan profiles at different wavelengths showed the detailed distribution of IQE values. The IQE values varied greatly depending not only on the difference between emitter and BSF regions but also on the rear side structure such as the electrode width and the distance between the emitter and BSF regions. On the other hand, the IQE spectra at over 950 nm improved by increasing the light absorbance ratio from the rear side. After module formation, the IQE spectra at short wavelengths were significantly reduced. The IQE properties were obtained from the front and rear sides. The difference in the short-circuit current between front side illumination and rear side illumination was mainly due to optical shading loss and carrier recombination loss at the BSF region. For a high cell efficiency, it is necessary to improve the passivation properties of the BSF region and optimize the electrode design.

A study on the 3D fluid flow of MHD micropump

In this paper, a 3D model of magnetohydrodynamic (MHD) micropump with a rectangular channel was modeled and numerically simulated based on the finite volume method. Effects of geometrical parameters such as depth, width, and length of the side electrodes were studied on the maximum flow rate, maximum pressure, and energy rate of the rectangular MHD channels in constant electric current and constant power supply modes. The multiple attributes decision-making method was used in order to identify the most effective geometrical parameters on the performance of the micropump. Wider channels with long electrodes are identified to be in favor of high performance for high flow rate, high pressure, and energy-efficient demands. A case study of new profile with a widened channel in the pumping section was proposed, and its new geometrical parameters are introduced. Studies at constant energy rate of 1 mW showed that the extension of the channel width (electrode walls) can increase the flow rate up to 1.23 μl/min (34% increase in comparison with non-extended channel). Additionally, it was found that when the extension parameter is set to 3.5 (D/w = 3.5), the flow rate is independent of the elongation parameter (r/R).

Incomplete partition typeIII revisited-long-term results following cochlear implant.

Incomplete partition typeIII (IPIII) is defined by amissing lamina cribrosa between the cochlea and the internal auditory canal (IAC). Cochlear implantation (CI) may result in an insertion of the electrode array into the IAC. The aim of this study is to evaluate CI surgery protocols, long-term audiological outcome, mapping and electrophysiological data after CI in IPIII patients. Nine IPIII patients were implanted with perimodiolar electrode arrays between 1999 and 2014; eight of them were included in this study. We evaluated mapping data, stapedius reflexes, electrode impedances and ECAP thresholds. We matched them with 3CI patients each with normal cochlear morphology regarding sex, age, side, implant type and surgical date. Speech discrimination was evaluated with the Oldenburger sentence test for adults, Göttingen audiometric speech test for children and the Freiburger monosyllabic word test. 3years after CI IPIII patients showed asignificant increase in pulse width, calculated electric load and electrode impedances in basal electrodes. Intraoperative electrically-evoked stapedius reflexes could be measured in all patients. Speech recognition scores were lower than average scores for matched patients, but without statistical significance. The significant increase of pulse width, electric load and electrode impedances of basal electrodes over time seem to be characteristic for IPIII patients probably occurring due to fibrosis and neurodegeneration of the cochlear nerve. The long term audiological results are stable. Intraoperative imaging and stapedius reflexes are highly recommended to control the right position of the electrode array.

Modeling of Interdigital Electrodes Geometrical Parameters Effects on Chemical Sensor Response

The detection of volatile organic compounds (VOCs), humidity and toxic industrial chemicals is important for various environmental and industrial applications. The design of interdigital capacitor (IDCs) sensor is carried out in such a way that it would be suitable for microelectronic technology. The basic geometry of IDCs is defined by some parameters such as: number of electrodes N, electrode width W, electrode length L and the separation between electrodes G. The interactions between IDCs sensitive coating and analyte induced a change in the sensors capacitance due to the permittivity variation of the sensitive layer and to the change in polymer thickness (swelling). In this work, a fairly new approach of IDCs based sensor in terms of capacitance calculation has been presented. The results have been obtained from the modeling of the sensors geometry 2D and 3D using multi-physics simulation software COMSOL. The effects of some geometry parameters coupled with swelling measurements for polymeric films have been studied.

Electric-Discharge Machining of Polymer Composites

The electric-discharge machining (EDM) of VKU-29 composite is experimentally studied. The influence of the machining conditions on the lateral electrode gap (the difference between the width of the slot in the polymer composite produced by EDM and the width of the tool electrode) is determined. The electrode gap observed in the machining of VKU-29 composite is analogous to that observed in the machining of steel workpieces. It depends on the pulse energy. Comparison of graphite, copper, and composite tool electrodes shows that the best surface quality is obtained in the latter case. In EDM by a composite electrode, no traces of damage or fluffing are seen on the machined surface.

Study of Electrode Fabrication in Diamond with a Femto‐Second Laser

Diamond is a radiation hard material, which makes it suitable for its use in high energy physics experiments as a particle detector. To further reduce the effects of radiation damage, diamond detectors can be fabricated by inscribing graphitic electrodes perpendicular to the surface—the so‐called 3D detectors. This can be done via processing with a femtosecond laser. Herein, a systematic study of the cross section of the graphitic wires inscribed into diamond is shown as a function of laser pulse energy, stage translational speed and, for the first time, polarization for a single crystal and polycrystalline chemical vapour deposition (CVD) diamond samples. No dependence of the electrode width with speed polarization and sample for the same pulse energies within uncertainties are observed. The graphitic content of the electrodes is studied in terms of Raman spectrometry: no clear dependence on the fabrication parameters studied is observed.

Incomplete partition typeIII revisited-long-term results following cochlear implant. German version

Incomplete partition typeIII (IPIII) is defined by amissing lamina cribrosa between the cochlea and the internal auditory canal (IAC). Cochlear implantation (CI) may result in an insertion of the electrode array into the IAC. The aim of this study is to evaluate CI surgery protocols, long-term audiological outcome, mapping and electrophysiological data after CI in IPIII patients. Nine IPIII patients were implanted with perimodiolar electrode arrays between 1999 and 2014; eight of them were included in this study. We evaluated mapping data, stapedius reflexes, electrode impedances and ECAP thresholds. We matched them with 3CI patients each with normal cochlear morphology regarding sex, age, side, implant type and surgical date. Speech discrimination was evaluated with the Oldenburger sentence test for adults, Göttingen audiometric speech test for children and the Freiburger monosyllabic word test. 3years after CI IPIII patients showed asignificant increase in pulse width, calculated electric load and electrode impedances in basal electrodes. Intraoperative electrically-evoked stapedius reflexes could be measured in all patients. Speech recognition scores were lower than average scores for matched patients, but without statistical significance. The significant increase of pulse width, electric load and electrode impedances of basal electrodes over time seem to be characteristic for IPIII patients probably occurring due to fibrosis and neurodegeneration of the cochlear nerve. The long term audiological results are stable. Intraoperative imaging and stapedius reflexes are highly recommended to control the right position of the electrode array.

Highly-Sensitivity and Self-Powered Ocean Wave Sensor Based on Liquid-Solid Interfacing Triboelectric Nanogenerator

Accurate forecasts of wave conditions are essential for marine engineering construction, development and utilization of ocean resources, environmental protection, maritime safety and early warning of marine disasters. There are many types of wave monitoring techniques, such as wave rider buoys, acoustic Doppler current profilers, high frequency radar and remote sensing [1]. Due to each of the techniques has its own advantages and disadvantages, it is essential to choose and develop proper techniques according to the requirements and conditions of applications. These commercial wave monitoring techniques are mainly applied for routine monitoring of waves and currents in the offshore and nearshore regions [2, 3]. To enhance the environmental sensing ability of smart marine equipment, it is important to develop a highly sensitive wave sensor to monitor the interaction between ocean waves and marine equipments, such as offshore platforms and ships. In this paper, a novel wave sensor based on liquid-solid interfacing triboelectric nanogenerator (WS-TENG) is proposed and investigated. The WS-TENG is made of a long copper electrode covered by a poly-tetra-fluoroethylene (PTFE) film with a microstructural surface. The effects of substrate, wave height, frequency, and water salinity on the sensitivity of the wave sensor are experimentally studied and analyzed. It is found that the output voltage peak of WS-TENG varies linearly with wave height. The WS-TENG with the electrode width of 10mm has a sensitivity of 0.023 V/mm, suggesting that the present novel sensor can sense the wave height in the millimeter range. The sensitivity would be increased further by widening the electrode, and/or enhancing the surface hydrophobicity. In contrast, the output voltage peak of WS-TENG is independent of wave frequency. Furthermore, the output voltage decays dramatically when water salinity is increased from 0 to 0.035 g mL−1. This may be due to high ions concentration reduces induced charges in electrodes [4]. It is worth to note that the linear relationship between the output voltage of WS-TENG and wave height is still valid at different salinities. In a simulated wave tank, the wave sensor is successfully used for real-time monitoring of the wave around the simulated offshore platform. Therefore, the wave sensor provides an alternative and self-powered approach to monitor waves’ characteristics.

Modeling and development of radio frequency planar interdigital electrode sensors

The interdigital sensor has been implemented in various field of applications such as microwave device, chemical sensor and biological sensor. This work describes the design and fabrication of an interdigital sensor (IDS) design that has the potential of estimating blood glucose levels using capacitive measurements. The IDS was first designed using theoretical equations and later was optimized by using CST Microwave Studio®. The electrode widths of the sensor were varied from 0.5mm to 0.7mm and the S11 reflection characteristics were simulated.Upon completion of simulations, the sensor was fabricated using copper clad FR4 boards. The fabricated sensors were measured using a vector network analyzer (VNA) and produced resonance frequencies of 2.02, 2.11 and 2.14 GHz. The highest Q obtained was 11.72 from the 2.11 GHz sensor.

The Influence of Geometry-Induced Frequency Dispersion on the Impedance Response of Interdigitated Electrodes

Interdigitated electrodes consist of interlaced electrode and counterelectrode fingers deposited on a non-conductive substrate. The electrode digits typically have a length on the order of millimeters, a width on the order of micrometers, and a separation distance on the order of micrometers. The diminutive dimensions of the electrochemical cell allow for low-noise impedance measurements and allow for the extraction of the electrical properties of the media in contact with the electrodes. Interdigitated electrodes are commonly utilized in measurements employing electrochemical impedance spectroscopy. Applications for interdigitated electrodes include the detection of contaminants, anti-corrosion coatings, and label-less detection of cells and viruses. Previous modeling of interdigitated electrodes was achieved by conformal mapping and finite-element methods and yielded estimates of the high-frequency ohmic resistance. The objective of our work was to determine the influence of geometry-induced frequency dispersion on the impedance response of interdigitated electrodes. Three aspects of the interdigitated electrode geometry were analyzed using finite-element simulations: the working-electrode width, the counterelectrode proximity to the working electrode, and the working electrode height. The meshing and domain size followed that developed for a disk-electrode geometry, for which ohmic resistances were obtained within 0.0009% of the analytic solution for an isolated disk electrode.1 The observations of the simulated impedance responses provided insight into the interpretation and analysis of data obtained using an interdigitated-electrode geometry. The ohmic response of the electrolyte may best be described as a complex frequency-dependent ohmic impedance with asymptotic real values of ohmic resistance in the high- and low-frequency limits.2 For an isolated flat embedded rectangular electrode, the geometry-induced frequency dispersion yielded a low-frequency ohmic resistance that was 1.29% larger than the high-frequency ohmic resistance. The high-frequency ohmic resistance was equal to that obtained for a primary current distribution. In the presence of a mirror-image counterelectrode, the ohmic resistances at high and low frequency were reduced up to an order of magnitude in comparison to an isolated electrode. The ratio of the low-frequency and high-frequency ohmic resistance ranged from 1.014 to 1.951 and was a function of the distance between the electrodes. Simulations were also performed that accounted for a finite electrode height for equal electrode width and spacing. Two characteristic frequencies were identified in the simulations; one that corresponded to the geometric capacitance of the interdigitated electrochemical cell, and one that corresponded to onset of low-frequency geometry-induced frequency dispersion. References Newman, “Resistance for Flow of Current to a Disk,” Journal of the Electrochemical Society, 113(5) (1966), 501-501.Huang, V. Vivier, M. E. Orazem, N. Pébère, and B. Tribollet, “The Apparent Constant-Phase-Element Behavior of an Ideally Polarized Blocking Electrode: A Global and Local Impedance Analysis,” Journal of The Electrochemical Society, 154 (2007), C81-C88.

Nozzle-Shaped Electrode Configuration for Dielectrophoretic 3D-Focusing of Microparticles.

An experimentally validated mathematical model of a microfluidic device with nozzle-shaped electrode configuration for realizing dielectrophoresis based 3D-focusing is presented in the article. Two right-triangle shaped electrodes on the top and bottom surfaces make up the nozzle-shaped electrode configuration. The mathematical model consists of equations describing the motion of microparticles as well as profiles of electric potential, electric field, and fluid flow inside the microchannel. The influence of forces associated with inertia, gravity, drag, virtual mass, dielectrophoresis, and buoyancy are taken into account in the model. The performance of the microfluidic device is quantified in terms of horizontal and vertical focusing parameters. The influence of operating parameters, such as applied electric potential and volumetric flow rate, as well as geometric parameters, such as electrode dimensions and microchannel dimensions, are analyzed using the model. The performance of the microfluidic device enhances with an increase in applied electric potential and reduction in volumetric flow rate. Additionally, the performance of the microfluidic device improves with reduction in microchannel height and increase in microparticle radius while degrading with increase in reduction in electrode length and width. The model is of great benefit as it allows for generating working designs of the proposed microfluidic device with the desired performance metrics.

Influence of electrode width on performance of planar on-chip micro-supercapacitors based on self-assembled graphene at liquid-air interface

Planar on-chip micro-supercapacitors (POMSs) with interdigital configuration were produced by photolithography and self-assembly of liquid-air interface. It is notable that the electrochemical performance of the POMS was significantly enhanced by reducing the electrode width from 300 μm to 180 μm, which highlight the importance of adjusting the width of electrode when creating high-performance POMS. It produced an area capacitance of 0.26 μF cm−2. In addition, POMS provide a power density of 0.825W cm−3, much higher than the power density of the electrolytic capacitor, and capacitor retention rate after 2000 cycles stabilized at 82.5%.

Dependence of enhancement factor on electrode size for field emission current from carbon nanotube on silicon wafer

This work studies the enhancement factor associated with a current emitted from a multi-wall carbon nanotube to an extremely small counter electrode. The experimental data show that the field enhancement factor increases by 1.15 times when the width of the counter electrode increases from 50 to 200 nm. To better understand this enhancement effect, field intensities at the emitter surface are numerically simulated. The experimental work and simulations demonstrate that the observed field enhancement results from increases in the capacitance between the emitter and counter electrode. In addition, corrugated counter electrodes are found to greatly affect both the capacitance and enhancement factor. This is because the corrugation of the anode surface raises the capacitance and thus provides a higher current. We experimentally show that an effective surface area enlargement of 1.67 times due to the corrugation provides a 1.06-fold increase of the enhancement factor. These results should assist in the future development of field emission devices based on semiconductor fabrication processes.

The Effect of Sensor Structure and Coplanar Electrode for Capacitive Based Flow Sensor

This paper presents the analysis of the capacitive based flow sensor using computational fluid dynamic (CFD) and mathematical equation approach. The CFD simulations for different types of sensor structure were carried out. Pressure and velocity of the fluid were varied in order to study the hydrodynamic parameter such as displacement and drag force. For the coplanar electrode, width of electrode and half gap between electrodes were varied for capacitive response using mathematical approach. Based on the simulation, the displacement of the dome increases as the pressure increases. The result shows that the most suitable thickness of the dome is 0.1 mm based on the displacement and the strain. Meanwhile for the coplanar electrode, the width and half gap showed a significant effect on the capacitance response.

A new plasma actuator configuration for improved efficiency: the stair-shaped dielectric barrier discharge actuator

Plasma actuators have shown their ability for different applications within the active flow control and heat transfer fields. These simple devices are inexpensive, present robustness, low weight and are fully electronic. However, they still present some debilities in terms of durability and maximum induced flow velocity. To overcome these issues, during the last years, a few different configurations of dielectric barrier discharge plasma actuators have been proposed but, always making use of dielectric barrier discharge layers of constant thickness. For the first time, the present study herein introduces a new plasma actuator configuration that makes use of a stair-shaped dielectric layer, which aims to increase the induced flow velocity and improve the mechanical efficiency without compromising the durability of the device. In this new concept, instead of using a dielectric layer with constant thickness, the thickness of the dielectric layer decreases along the covered electrode width, which leads to an increase of the plasma discharge extension and an increase of the maximum induced flow velocity. Several actuators based on a stair-shaped dielectric layer were experimentally tested and compared with the conventional actuators. The results demonstrated that the stair-shaped actuators allow us to obtain a plasma discharge longer. It was found that by implementing a stair-shaped dielectric layer with a slope angle, in a 1.92 mm thickness actuator, it is possible to increase the maximum induced flow velocity in about 32% by consuming 36% less power. These results lead to a mechanical efficiency five times bigger than the obtained with conventional constant thickness actuators.

Study on sensitivity characteristic of capacitive coupler for PD detection in HV cable joint

The capacitive coupler is an attractive tool for on‐site partial discharge (PD) detection in a cable joint. To study its sensitivity characteristic, PDs in a 110‐kV prefabricated joint containing two artificial defects were detected successively using capacitive couplers with six different electrode widths installed at the same position of the cable. For the quantification of sensor sensitivity, the sensitivity factor is defined as the ratio of capacitive coupler output voltage amplitude to apparent charge that was determined through a conventional PD‐measuring circuit according to IEC 60270. As random variables, the sensitivity factors were displayed in the probability distribution plots for each capacitive coupler to visually compare their sensitivity levels. The results demonstrate an almost monotonically increasing dependence of sensitivity on the coupling electrode width, which agrees with the qualitative analysis based on the amplitude–frequency characteristic of the capacitive coupler. Besides, there is an obvious distinction in sensitivity factors between two distinct defects, indicating that the capacitive coupler is more suitable for PD trend analysis rather than apparent charge quantification. In addition, the insensitivity of the capacitive coupler to certain defect types may explain the cause of some undetectable dead zones in on‐site PD measurement. This study provides experimental support for the geometrical optimization of capacitive couplers. © 2019 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

Design and fabrication of a D33-mode piezoelectric micro-accelerometer

In this paper, a D33-mode piezoelectric micro-accelerometer with Pb1.1(Zr0.52Ti0.48)O3(PZT) thin film is designed, fabricated and tested. Both the polarization and deformation directions of the piezoelectric thin film are horizontal in this structure. With the high sensitivity and natural frequency, the D33-mode piezoelectric micro-accelerometer possesses improved practicality. The influence of filling factor (Γ) and interdigital electrode width (b) on the output voltage is analyzed in this work. The micro-electro-mechanical systems technology is then used to fabricate the piezoelectric accelerometer device, which is based on the Sol–Gel PZT piezoelectric thin film. Performance of the piezoelectric accelerometer micro-devices with the different Γ and b is tested on the vibration table. The experimental results show that the sensitivity of D33-mode piezoelectric accelerometer is inversely to the filling factor and interdigital electrode width. The piezoelectric accelerometer with a filling factor of 0.5 and an interdigital electrode width of 5 μm can generate an output voltage of 149.83 mV.

Improving Wall Slip Behavior of Silver Pastes on Screen Emulsions for Fine Line Screen Printing

The ongoing demand for a further reduction of electrode width for solar cell metallization by flatbed and rotary screen printing is one of the main challenges in recent years. The main focus was on the improvement of silver paste printability which is strongly influenced by its rheological behavior. Furthermore, the impact of slip behavior in contact with smooth surfaces e.g. mesh wires and emulsion plays an important role when printing of small electrode width is desired. Therefore, four types of coatings for screen emulsions are investigated in terms of their wall slip behavior with commercial available silver pastes. For this reason, a novel parameter slip efficiency β is introduced which enables the prediction of potential improvements in fine line screen printing by slip effects at the paste-emulsion interface. Furthermore, contact angles on coated surfaces with respective paste solvents are measured and an exponential correlation between both is discovered. Finally, metallization results of a PERC solar cell batch for the two best coating candidates are presented and a correlation between printed electrode width and slip efficiency during screen printing is given. For the best coating, an average finger resistance of 99 Ω/m at an average finger width of 26.2 μm was demonstrated which shows a significant improvement compared to the reference with a finger resistance of 164 Ω/m for 27.7 μm finger width.

Modified Peek formula for calculating positive DC corona inception voltage on polluted insulator

In this contribution, a mathematical model is proposed to predict the discharge inception voltage on polluted insulators under a non-uniform field of a high-voltage DC system. The present study is derived from the modified Peek’s law used for predicting the threshold voltage of a typical corona discharge. An onset criterion useful for practical electrode geometries was experimentally validated by considering insulators’ level of pollution along with the electro-geometrical parameters including inter-electrode distance, HV electrode radius, and width of the ground electrode. It was observed that the proposed mathematical model is much precise for smaller electrode radii and inter-electrode distances with higher conductivity of the pollution layer. Since prediction of the electrical onset on a polluted surface is of general interest for designing HV equipment suitable for heavily polluted regions in the world, it is hoped that the results presented can be viewed as a benchmark and a challenge for further research.

77‐5: Late‐News Paper: Advanced phase distribution algorithm in blazed grating for continuous beam steering

The electrically tunable beam deflector have been researched and developed for lots of purpose. For the transmission type beam deflector, an indium‐tin‐oxide (ITO) has been developed with blazed grating patterns. The ITO layer was designed and generated on the lower substrate for transmission type beam deflector. A pixel pitch of ITO grating patterns is 6um, the electrode width is 3um with 3um spacing. With this small pixel pitch, the maximum diffraction angle is 2.541° at a wavelength of 532nm. A minimum cell gap is 2.5um for the enough 2π phase modulation with high birefringence liquid crystal which is delta n, 0.31. Total 720‐ ITO line which was patterned on the lower substrate is controlled individually by driving integrated circuit (IC) from driving module. Beam deflector driving module with driving IC is designed for continuous beam steering. Driving algorithm is developed and applied to the driving system for high angular resolution and continuous beam steering.