Electrical Characterization Tests Research Articles

An artificial optoelectronic synapse based on MoO x film

Artificial optoelectronic synapses have the advantages of large bandwidth, low power consumption and low crosstalk, and are considered to be the basic building blocks of neuromorphic computing. In this paper, a two-terminal optoelectronic synaptic device with ITO-MoO x -Pt structure is prepared by magnetron sputtering. The performance of resistive switching (RS) and the photo plastic properties of the device are analyzed and demonstrated. Electrical characterization tests show that the device has a resistive HRS/LRS ratio of about 90, stable endurance, and retention characteristics of more than 104 s (85 °C). The physical mechanism of the device is elucidated by a conducting filament composed of oxygen vacancies. Furthermore, the function of various synaptic neural morphologies is successfully mimicked using UV light as the stimulation source. Including short-term/long-term memory, paired-pulse facilitation, the transition from short-term to long-term memory, and ‘learning-experience’ behavior. Integrated optical sensing and electronic data storage devices have great potential for future artificial intelligence, which will facilitate the rapid development of retina-like visual sensors and low-power neuromorphic systems.

Thermal design analysis for SuperTruck II lithium-titanate battery pack

This paper presents a systematic thermal management analysis for a new lithium-titanate-oxide battery pack to be installed in a SuperTruck II, Class 8 hybrid truck. The authors investigate the feasibility of mounting the battery pack inside the vehicle and air-cooling it with fans supplying conditioned air from the cabin. Moreover, the cells within each module are to be immersed in a heat-transfer fluid to improve temperature homogeneity. A multi-stage thermal analysis is performed to ensure adequate thermal regulation of the battery under the proposed design, considering installation and operational constraints. The authors perform thermal and electrical characterization tests on a single cell. Results inform the development of computational fluid dynamics models of the cells, modules, and pack. Module-level analysis shows that the cell temperatures can be maintained below their upper operational limit of 55 °C with module wall-to-air heat transfer coefficients between 10 and 20 Wm−2K−1. Pack-level analysis of distinct configurations determines effective airflow paths for adequate heat transfer and delivers a final battery pack design that achieves sufficient cooling and temperature uniformity. A reduced-order electrothermal model is developed to rapidly predict the transient battery performance and to develop a temperature control strategy.

Radiation Tolerant Multi-Bit Flip-Flop System With Embedded Timing Pre-Error Sensing

This article presents the design, implementation methodology, and validation of a multi-bit flip-flop (FF) system that provides tolerance against single-event upsets (SEUs) and single-event transients (SETs) caused by radiation strikes. The proposed solution also has embedded timing pre-error sensing capability, which enables closed-loop integration of digital systems to work at optimal operating point (OPP) without any fail. It allows efficient real-time dynamic voltage frequency scaling (DVFS) implementation in the digital system. It helps detect aging-related and total ionizing dose (TID)-induced timing degradation in digital circuits. It can be implemented with any standard digital cell library (non-rad-hard), thereby providing a cost-effective solution for rad-hard applications. The design is implemented in ST BCD 90-nm technology in multiple configurations of bit sizes. A digital system based on ARM cortex M4 microprocessor has also been implemented with the proposed FF and put on silicon for testing to validate various capabilities of the proposed design. The results are presented based on simulations, electrical characterization, and radiation tests.

Tunable Switching Behavior of GO-Based Memristors Using Thermal Reduction.

This work reports on the fabrication of a novel planar reduced graphene oxide (rGO) memristor (MR) device. For the first time in the literature, the MR tunable resistive switching behavior is controlled by the GO reduction time at a constant temperature. The device is fabricated using standard microfabrication techniques on a flexible cyclic olefin copolymer substrate (COC). Thermal reduction of the GO layer at low temperatures (100 °C) avoids the drawbacks of chemical reduction methods such as toxicity and electrode metal damage during fabrication, while allowing for fine-tuning of the MR’s switching behavior. The device has analog switching characteristics, with a range of different resistance states. By taking advantage of the slow nature of GO thermal annealing, the switching properties of the rGO memristors can be precisely controlled by adjusting the reduction period. At short annealing times (i.e., T < 20 h), the devices switch from high to low resistance states, while at longer annealing times the switching behavior is reversed, with the device switching from low to high resistance states (LRS to HRS). Resistive switching occurs as a result of the diffusion and removal of the oxygen functional groups in the GO film caused by Joule heating induced by the electric current. Complete electrical characterization tests are presented along with wettability and X-ray diffraction (XRD) tests. This work opens a new vision for realizing rGO-based MR devices with tunable switching properties, broadening the application horizon of the device.

Vibration-based degradation effect in rechargeable lithium ion batteries having different cathode materials for railway vehicle application

The performance of lithium-ion battery (LIB) has been studied under various conditions of temperature and load depending on the automotive application, since LIB is dominant in cathode active materials. However, majority of those studies are restricted to automotive applications for investigation of its performance. It is necessary to experiment with the impact of vibration and shock since railway vehicles are exposed to complex vibrations by components, railway conditions, and driving profiles. Because of these complex vibration conditions, the battery can be rapidly degraded along with the battery cycles. Thus, it is important to ensure that the actual battery life can be estimated. In this study, the effect of vibration on the LIB was analyzed. The batteries using three types of cathode active materials were observed in terms of electrical performance through electrical characterization tests. The degradation effects by complex vibrations were analyzed by monitoring its resistance, capacity, and incremental capacity. As a result, a battery with high durability was selected among LIBs with different active materials.

A New RFID-Identification Strategy Applied to the Marble Extraction Industry

This paper aims to improve the marble industry production chain by proposing new technological approaches using the Radio Frequency Identification (RFID) systems. The dynamic capabilities of the RFID read-write tags allow the storage of physical characteristics of stone blocks, according to electrical, ultrasound and three-dimensional image characterization tests. These characterization non-destructive tests allow the evaluation of important parameters of the original stone blocks, by analyzing the internal structure of the rocks. Then, these parameters can be stored in databases through RFID-tags, in order to optimize their subsequent cutting and transformation processes. RFID identification technology when integrated into an ethernet communication network enables automatic communication with cutting and processing equipment, building an intelligent industrial platform, integrating PCs (Personal Computers) and PLCs (Programmable Logic Controllers) within an Industry 4.0 environment. Another huge advantage of RFID technology is that it allows full product traceability, namely by enabling the end consumer to reverse the production path. A laboratory prototype was implemented and a detailed analysis and discussion of the obtained functionalities is shown at the end of this paper.

Multi-axial electro-mechanical testing methodology for highly stretchable freestanding micron-sized structures

Recent advances in MEMS technology have brought forward a new class of high-density stretchable/flexible electronics as well as large displacement MEMS devices. The in-situ electro-mechanical characterization of such devices is challenging since it requires: (i) highly delicate sample handling, (ii) controlled application of large (hundreds of µm) multi-axial displacements to mimic service conditions, (iii) integrated electrical testing and (iv) fast actuation for cyclic testing. Techniques already developed for small-scale testing in literature fall short to meet the combined set of requirements. To this end, a characterization methodology that fulfills all these requirements is developed and presented here. The technique is based on a piezo-driven micro-tensile stage, which provides large multi-axial displacements with high resolution and fast actuation (4000 µm/s). This is combined with a method for sample microfabrication on a test-chip to warrant delicate sample handling. Proof-of-principle experiments are shown for multi-axial mechanical characterization, electrical characterization and high cycle fatigue testing of micron-sized highly stretchable interconnects. Experiments are conducted under in-situ microscopic observation using optical microscopy, scanning electron microscopy, and high-resolution profilometry. The generic platform proposed here can be used for other problems where similar requirements are faced, e.g. other miniaturized, large displacement electro-mechanical applications that are currently being developed.

Experimental Response of Nonwoven Waste Cellulose Fabric–Reinforced Epoxy Composites for High Toughness and Coating Applications

In this article, the authors have fabricated (using the manual hand lay-up method) and characterized in detail the nonwoven waste cellulose fabric (with varying weight percentages of 0, 7, 9, and 11) reinforced epoxy resin composites. The methodology to develop in conjunction with various physical (density, water absorption, and thickness swelling), mechanical (tensile, compression, flexural, hardness, and impact), thermal (differential thermal analysis, thermogravimetric analysis, and derivative thermogravimetric analysis), morphological (scanning electron microscopy and X-ray diffraction), and electrical characterization tests were performed to give complete insight into the mechanics of epoxy fabric laminates. It was predicted from these tests that with an increasing weight percentage of fabric, most of the mechanical properties improved and were complemented through the microstructural morphological tests. Enhanced mechanical strength and thermal stability of the developed composite (relative to the neat epoxy resin) pave its way for high toughness and coating applications in various engineering fields.

Synergistic effect of adding lignin and carbon black in poly(lactic acid)

Abstract Antistatic packaging is a very important sector since the electrostatic discharge of electronic devices can damage and/or disable these products. In addition, it is essential to dispose of this packaging correctly. In this work, the synergistic effect of the addition of lignin and carbon black on the development of antistatic and biodegradable packaging was verified. In this study, PLA was mixed with lignin and carbon black and the composites were prepared using a high-speed thermokinetic homogenizer where the melting of the PLA and the blend with fillers occurred by friction. The composites were characterized by Izod impact tests, scanning electron microscopy, thermal properties, electrical characterization and biodegradation tests in garden soil. The results show that lignin is a great option to accelerate the biodegradation of PLA in the garden soil and the carbon black acts as an antistatic agent reducing the electrical resistivity of the composites.

Bioelectrochemical systems for energy storage: A scaled-up power-to-gas approach

The development and implementation of energy storage solutions is essential for the sustainability of renewable energy penetration in the electrical system. In this regard, power-to-gas technologies are useful for seasonal, high-capacity energy storage. Bioelectrochemical systems for electromethanogenesis (EMG-BES) represent an additional power-to-gas technology to the existing chemical and biological methanation. EMG-BES process can be retrofitted in traditional anaerobic digesters, with advantages in terms of biologic process stability and high-quality biogas production. Nowadays, there are no reported studies of scaled-up EMG-BES plants for energy storage. The present work describes the setup and operation of a medium-scale EMG-BES prototype for power-to-gas, storing energy in the form of biomethane. The prototype was built by stacking 45 EMG-BES cells, accounting for a total volume of 32 L. It was continuously fed with 10 L day−1 municipal wastewater, and it was long-term operated at different voltage and temperature ranges. A steady-state current density demand of 0.5 A m−2 was achieved at 32 °C while producing 4.4 L CH4 m−2 d−1 and removing 70% of the initial organic matter present in wastewater. Microbial competition between electro-active bacteria and acetoclastic methanogens was observed. Energy storage efficiency was estimated around 42–47%, analyzing surplus CH4 production obtained when applying voltage to the stack. A first order electric model was calculated, based on the results of a series of electrical characterization tests. The model may be used in the future to design the converter for EMG-BES plant connection to the electrical grid. The obtained results show that energy storage based on EMG-BES technology is possible, as well as its future potential, mixing renewable power overproduction, biomethane generation and wastewater treatment under the circular economy umbrella.

Fast Electrical Characterizations of High-Energy Second Life Lithium-Ion Batteries for Embedded and Stationary Applications

This paper focuses on the fast characterization of automotive second life lithium-ion batteries that have been recently re-used in many projects to create battery storages for stationary applications and sporadically for embedded applications. Specific criteria dedicated to the second life are first discussed. After a short review of the available state of health indicators and their associated determination techniques, some electrical characterization tests are explored through an experimental campaign. This offline identification aims to estimate the remaining ability of the battery to store energy. Twenty-four modules from six different commercial electric vehicles are analyzed. Well-known methodologies like incremental capacity analysis (ICA) and constant voltage phase analysis during CC-CV charge highlight the difficulty—and sometimes the impossibility—to apply traditional tools on a battery pack or on individual modules, in the context of real second life applications. Indeed, the diversity of the available second life batteries induces a combination of aging mechanisms that leads to a complete heterogeneity from a cell to another. Moreover, due to the unknown first life of the battery, typical state of health determination methodologies are difficult to use. A new generic technique based on a partial coulometric counter is proposed and compared to other techniques. In the present case study, the partial coulometric counter allows a fast determination of the capacity aging. In conclusion, future improvements and working tracks are addressed.

Preparation and characterization of antistatic packaging for electronic components based on poly(lactic acid)/carbon black composites

ABSTRACTPoly(lactic acid) (PLA) is a biodegradable aliphatic polymer obtained from renewable sources; its main application is in the packaging sector. Electronic components require the use of antistatic packaging that prevents damage and electric shock. As PLA has no conductive characteristics, it requires the addition of allotropic carbon forms such as conductive carbon black to make the polymer less resistive as the dissipative material and making it suitable for the manufacture of antistatic packaging. In this study, PLA was melt blended with 5, 10, and 15 wt % of carbon black. The composites were prepared using a high‐speed mixer. Samples were characterized by Izod impact resistance tests, scanning electron microscopy, thermal properties, electrical characterization, and biodegradation tests in garden soil. The addition of carbon black in the PLA matrix increases the temperature of degradation and decreases the crystallinity degree and the impact resistance of the composites. However, carbon black is a great option to increase the electrical conductivity of PLA. The addition of carbon black in PLA makes the composite less resistive and suitable for use as antistatic packaging for the transportation and storage of electronic components. Furthermore, this composite does not cause damage to the environment as the carbon black does not interfere in the degradation mechanism of PLA. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47273.

Fabrication, electrical characterization and mechanical flexibility test of back gated carbon nanotube thin film transistors on polyimide substrate

This work demonstrates the scalable method of fabricating back gated carbon nanotube thin film transistors (CNTTFTs) on a polyimide (kapton) substrate using photo lithography and lift-off process for patterning gate dielectrics and metals deposited for electrodes , and dip coating method for single walled carbon nanotubes deposition on functionalized dielectric surface. The CNTTFTs of varying dimensions are fabricated and electrical characterizations are done at room temperature and the CNTTFTs have exhibited p-type behaviour. The CNTTFT of channel length(L) 3 μm, width(W) 10 μm exhibits on-off current ratio of 9.219 × 105, carrier mobility of 4.9 cm2 V−1 s−1, trans conductance of 26 μS and on current of 472 μA when the substrate is kept flat (not bent). The mechanical flexibility test of CNTTFTs is done by conducting electrical characterization of CNTTFTs with the substrate bent to different diameters. Irrespective of the channel length, CNTTFTs have exhibited minimal change in the electrical characteristics when bent to 14 mm diameter. However, short channel CNTTFT (L = 3 μm) has shown considerable change in electrical characteristics when bent to 8 mm diameter compared to long channel length CNTTFT (L = 75 μm). The fabricated back gated flexible CNTTFTs work as CNTTFTs when bent up to the diameter of 8 mm, demonstrates that the CNTTFTs can be used for practical applications in the area of flexible electronics.

Influence of Mechanical Pressure on the Electrical Performance of Lithium-Ion Silicon Batteries

Lithium-ion batteries are the state of the art in electronic consumer products, ranging from smartphones to cars. Demands on lifetime and energy/power density are ever increasing to extend the duration the battery can be used. Hence, there is a continuous need to further improve lithium-ion batteries [1]. This is exactly what has been tackled in the European project FiveVB, which strives to increase the energy density of a battery as well as to perform a thorough study of the aging phenomena. One of these improvements in energy density can be achieved by using lithium-silicon alloys as negative electrode because of the high theoretical capacity of silicon (3.600 mAh/g) which is 10 times higher than the one of graphite, used in most lithium-ion batteries as negative electrode. The high theoretical capacity of Li-Si alloys has been known for a long time but their practical application has been prevented by serious issues associated with large volume expansion (>200%) during lithium uptake, that induce cracks and mechanical disintegration of the electrode, finally leading to losses of electronic contact and a severe capacity fading already after a number of cycles [2], [3]. This disadvantage has been investigated and improved by using a dedicated electrolyte as well as a special designed negative electrode. Throughout the project an extended electrical characterization has been performed on silicon based non-commercial pouch cells. One important conclusion is that effect of mechanical pressure on this cell has a significant influence on its performance: mainly capacity retention (ultimately cycle life) and energy density. In this paper this influence will be discussed in detail by using classical electrical characterization tests such as an Open-Circuit Voltage test (OCV), a capacity test and Hybrid Pulse Power Characterization (HPPC) test complying with the existing standards. In this abstract only the capacity test will be discussed, the remaining tests will be discussed in the full paper. Results and discussion: The procedure used during the capacity test consists of standard charging phase (constant current and constant voltage) followed by several discharges at different C-rates (C/5, C/3, 1C & 1.5C), based upon the international standard IEC 62660-1. The current and its corresponding voltage response of a capacity test of the clamped Si-alloy pouch cells is visualized in figure 1. Figure 2 provides a comparison of the discharge capacity of both the clamped an unclamped pouch cells. It can be clearly seen that when clamping the cell a significant increase of 10-20% in the discharge capacity can be observed. The most probable root cause of this difference is due to gassing of the negative electrodes because after the electrical characterization tests it can be clearly observed that the unclamped pouch cells are swollen and the clamped ones show no signs of swelling. These gasses are not conductive resulting in regions of low conductivity which are not taking part anymore in the electrochemical reactions. The clamped cell shows no swelling which can be explained by two reasons: firstly, it is possible that due to the pressure of clamping the gassing is reduced or secondly that the gas is pushed to the side of the cell where it doesn’t interfere with the electrochemical reactions. Since no gassing is observed the firstly is more likely. An extended analysis of the effect of mechanical pressure on the electrical performance will be discussed in detail in the full paper by means of the remaining electrical characterization tests (OCV and HPPC) as well as an extended investigation of the root cause will be discussed in the full paper.

Evaluation of the Morphological, Electrical, and Mechanical Properties of Silver Nanopastes

Abstract This study investigated the sintering behavior of silver nanopastes at 150°C, 180°C, and 210°C. The synthesized silver nanoparticles were dispersed to form ink pastes with 70 wt. % and 80 wt. % silver. The morphology of the sintered silver nanopastes was studied via transmission electron microscopy (TEM), scanning electron microscopy, and x-ray diffraction analyses. Electrical characterization, thermal/humidity aging, and mechanical testing were also performed. Silver nanoparticles were prepared via a chemical reduction method. TEM images revealed particle sizes ranging from 10 nm to 20 nm. Results showed that electrical conductivity could be achieved at 150°C. When the sintered silver nanoparticles were subjected to 1000 h of 85°C/85 % relative humidity testing, a stable resistivity was achieved at a sintering temperature no lower than 210°C. These results showed that a stable network of sintered silver nanoparticles with good mechanical properties could be achieved at 210°C.

Instrumentation for Innovative Semiconductor Power Devices Reliability Tests

An automated system, designed to perform innovative reliability tests on semiconductor power devices, is reported. Hardware and software modules have been specifically developed for the demonstration of the proposed methodology. Both High Temperature Reverse Bias (HTRB) and Electrical Characterization Test (ECT) are executed by the system on power transistors, increasing operation parameters beyond their rated temperature and voltage values in order to accelerate the device wearing out. Thanks to a purposely designed mini-heater, the system tightly controls the individual chip temperature, while allowing the testing of many devices at a time. Electrical parameters can be periodically measured in order to determine early warnings of device failure, being able to stop their stress, both thermal and electrical, avoiding uncontrolled thermal runaway effects that often lead to package explosion. This strategy, on one hand, can avoid interruption of the remaining device test and, on the other hand, make it possible to perform, after the test end, the most complete post-failure analysis. A non-standard procedure for HTRB tests, based on the division of the total stress time in several short periods, is proposed.

Reliability of wire-bonded electronic devices in combined high temperature and vibrational environments

High temperature electronic systems need to operate in extreme conditions that exceed the current levels specified by the military and aerospace standards. In high temperature and wide operating temperature applications, electronics can suffer from failure modes caused by a combination of environmental and operational loadings such as temperature, vibration, humidity, pressure, external stresses, etc. This work reports the findings and observations of the investigation of the combined effects of thermal and vibrational environments on wire-bonded interconnections used in high temperature electronic components. The work is focused on combined testing at temperatures up to 250°C and vibration loading with the sine frequency swept cycles ranging from 5Hz to 2000Hz and acceleration up to 20g rms. Analysis is focusing on the wire bond connections which has shown an increasing occurrence of wire deformation at a test temperature of 250°C whilst being subjected to vibration, particularly for wires with large loop shapes. Wire bonded samples have been evaluated through visual inspection, electrical characterization and ball shear tests to identify failure mechanisms.

Deep-Brain Silicon Multielectrodes for Simultaneous Neural Recording and Drug Delivery

Abstract Silicon micromachined deep brain multielectrodes (up to 70 mm) with monolithically integrated microfluidic channels have been realized to perform simultaneous electrical recording and drug delivery in deep brain regions. Fabrication process of the drug delivery channels and the Pt recording sites is demonstrated. Electrical characterization, impedance tuning and in-vivo testing of the developed probes are also presented. The functionality of the buried microfluidic channel is verified and pressure-flow characteristic of the channel is established.

Experimental study of high electric current effects in carbon/epoxy composites

Electrical and thermal behavior of the carbon fiber-reinforced epoxy composites subjected to relatively high (up to 75 A) steady electric currents is studied. A fully automated experimental setup for real time measurements of the electric current, resistance, voltage, and temperature in carbon fiber-reinforced epoxy matrix composites has been developed. A series of electrical characterization tests on IM7/977-3 unidirectional and symmetric cross-ply composite laminates have been performed and the effects of electric current magnitude and duration, electrical resistance, and associated thermal effects have been investigated. It is determined that electrical resistance exhibits time-dependent behavior. It is also found that application of an electric current leads to a significant temperature rise in the composites that is a result of the intense Joule heat produced in the electrically conductive carbon fibers as well as in the composite-electrode contact.

Electrical Characterization and Preliminary Beam Test Results of 3D Silicon CMS Pixel Detectors

The fabrication of 3D detectors which requires bulk micromachining of columnar electrodes has been realized with advancements in MEMS technology. Since the fabrication of the first 3D prototype in Stanford Nanofabrication Facility in 1997, a significant effort has been put forth to transfer the 3D detector technology to large scale manufacturing for future high luminosity collider experiments, in which the radiation hardness will be the primary concern, and other applications such as medical imaging and X-ray imaging for molecular biology. First, alternative 3D structures, single type column (STC) and double-side double type column (DDTC) 3D detectors, were produced at FBK-irst (Trento, Italy) and CNM-Barcelona (Spain), and assessed thoroughly to improve the production technology towards the standard full-3D detectors. The 3D collaboration has been extended to include SINTEF (Norway), which is committed to small to medium scale production of active edge full-3D silicon sensors. This paper focuses on p-type 3D detectors compatible with the CMS pixel front end electronics from the second run of fabrication at SINTEF clean room facilities. The sensors that passed the wafer level electrical characterization have been bump-bonded at IZM (Germany), assembled into modules and wire-bonded for functional characterization at Purdue University. We report the leakage current characteristics, bump-bond quality, threshold, noise, and gain measurement results of these 3D modules as well as the preliminary beam test data taken at Fermi National Accelerator Laboratory.