EPR and transient capacitance studies on electron-irradiated silicon solar cells

Science.gov (United States)

Lee, Y. H.; Cheng, L. J.; Mooney, P. M.; Corbett, J. W.

1977-01-01

One and two ohm-cm solar cells irradiated with 1 MeV electrons at 30 C were studied using both EPR and transient capacitance techniques. In 2 ohm-cm cells, Si-G6 and Si-G15 EPR spectra and majority carrier trapping levels at (E sub V + 0.23) eV and (E sub V + 0.38) eV were observed, each of which corresponded to the divacancy and the carbon-oxygen-vacancy complex, respectively. In addition, a boron-associated defect with a minority carrier trapping level at (E sub C -0.27) eV was observed. In 1 ohm-cm cells, the G15 spectrum and majority carrier trap at (E sub V + 0.38) eV were absent and an isotropic EPR line appeared at g = 1.9988 (+ or - 0.0003); additionally, a majority carrier trapping center at (E sub V + 0.32) eV, was found which could be associated with impurity lithium. The formation mechanisms of these defects are discussed according to isochronal annealing data in electron-irradiated p-type silicon.

Reduction of parasitic capacitance in 10 kV SiC MOSFET power modules using 3D FEM

DEFF Research Database (Denmark)

Jørgensen, Asger Bjørn; Christensen, Nicklas; Dalal, Dipen Narendrabhai

2017-01-01

The benefits of emerging wide-band gap semiconductors can only be utilized if the semiconductor is properly packaged. Capacitive coupling in the package causes electromagnetic interference during high dv/dt switching. This paper investigates the current flowing in the parasitic capacitance between...... the output node and the grounded heat sink for a custom silicon carbide power module. A circuit model of the capacitive coupling path is presented, using parasitic capacitances extracted from ANSYS Q3D. Simulated values are compared with experimental results. A new iteration of the silicon carbide power...

Development of AC-coupled, poly-silicon biased, p-on-n silicon strip detectors in India for HEP experiments

Science.gov (United States)

Jain, Geetika; Dalal, Ranjeet; Bhardwaj, Ashutosh; Ranjan, Kirti; Dierlamm, Alexander; Hartmann, Frank; Eber, Robert; Demarteau, Marcel

2018-02-01

P-on-n silicon strip sensors having multiple guard-ring structures have been developed for High Energy Physics applications. The study constitutes the optimization of the sensor design, and fabrication of AC-coupled, poly-silicon biased sensors of strip width of 30 μm and strip pitch of 55 μm. The silicon wafers used for the fabrication are of 4 inch n-type, having an average resistivity of 2-5 k Ω cm, with a thickness of 300 μm. The electrical characterization of these detectors comprises of: (a) global measurements of total leakage current, and backplane capacitance; (b) strip and voltage scans of strip leakage current, poly-silicon resistance, interstrip capacitance, interstrip resistance, coupling capacitance, and dielectric current; and (c) charge collection measurements using ALiBaVa setup. The results of the same are reported here.

Wind turbine clutter mitigation in coastal UHF radar.

Science.gov (United States)

Yang, Jing; Pan, Chao; Wang, Caijun; Jiang, Dapeng; Wen, Biyang

2014-01-01

Coastal UHF radar provides a unique capability to measure the sea surface dynamic parameters and detect small moving targets, by exploiting the low energy loss of electromagnetic waves propagating along the salty and good conducting ocean surface. It could compensate the blind zone of HF surface wave radar at close range and reach further distance than microwave radars. However, its performance is susceptible to wind turbines which are usually installed on the shore. The size of a wind turbine is much larger than the wavelength of radio waves at UHF band, which results in large radar cross section. Furthermore, the rotation of blades adds time-varying Doppler frequency to the clutter and makes the suppression difficult. This paper proposes a mitigation method which is based on the specific periodicity of wind turbine clutter and performed mainly in the time-frequency domain. Field experimental data of a newly developed UHF radar are used to verify this method, and the results prove its effectiveness.

Analysis strategies for high-resolution UHF-fMRI data.

Science.gov (United States)

Polimeni, Jonathan R; Renvall, Ville; Zaretskaya, Natalia; Fischl, Bruce

2018-03-01

Functional MRI (fMRI) benefits from both increased sensitivity and specificity with increasing magnetic field strength, making it a key application for Ultra-High Field (UHF) MRI scanners. Most UHF-fMRI studies utilize the dramatic increases in sensitivity and specificity to acquire high-resolution data reaching sub-millimeter scales, which enable new classes of experiments to probe the functional organization of the human brain. This review article surveys advanced data analysis strategies developed for high-resolution fMRI at UHF. These include strategies designed to mitigate distortion and artifacts associated with higher fields in ways that attempt to preserve spatial resolution of the fMRI data, as well as recently introduced analysis techniques that are enabled by these extremely high-resolution data. Particular focus is placed on anatomically-informed analyses, including cortical surface-based analysis, which are powerful techniques that can guide each step of the analysis from preprocessing to statistical analysis to interpretation and visualization. New intracortical analysis techniques for laminar and columnar fMRI are also reviewed and discussed. Prospects for single-subject individualized analyses are also presented and discussed. Altogether, there are both specific challenges and opportunities presented by UHF-fMRI, and the use of proper analysis strategies can help these valuable data reach their full potential. Copyright © 2017 Elsevier Inc. All rights reserved.

UHF Signal Processing and Pattern Recognition of Partial Discharge in Gas-Insulated Switchgear Using Chromatic Methodology.

Science.gov (United States)

Wang, Xiaohua; Li, Xi; Rong, Mingzhe; Xie, Dingli; Ding, Dan; Wang, Zhixiang

2017-01-18

The ultra-high frequency (UHF) method is widely used in insulation condition assessment. However, UHF signal processing algorithms are complicated and the size of the result is large, which hinders extracting features and recognizing partial discharge (PD) patterns. This article investigated the chromatic methodology that is novel in PD detection. The principle of chromatic methodologies in color science are introduced. The chromatic processing represents UHF signals sparsely. The UHF signals obtained from PD experiments were processed using chromatic methodology and characterized by three parameters in chromatic space ( H , L , and S representing dominant wavelength, signal strength, and saturation, respectively). The features of the UHF signals were studied hierarchically. The results showed that the chromatic parameters were consistent with conventional frequency domain parameters. The global chromatic parameters can be used to distinguish UHF signals acquired by different sensors, and they reveal the propagation properties of the UHF signal in the L-shaped gas-insulated switchgear (GIS). Finally, typical PD defect patterns had been recognized by using novel chromatic parameters in an actual GIS tank and good performance of recognition was achieved.

Modeling and analysis of power extraction circuits for passive UHF RFID applications

International Nuclear Information System (INIS)

Fan Bo; Dai Yujie; Zhang Xiaoxing; Lue Yingjie

2009-01-01

Modeling and analysis of far field power extraction circuits for passive UHF RF identification (RFID) applications are presented. A mathematical model is derived to predict the complex nonlinear performance of UHF voltage multiplier using Schottky diodes. To reduce the complexity of the proposed model, a simple linear approximation for Schottky diode is introduced. Measurement results show considerable agreement with the values calculated by the proposed model. With the derived model, optimization on stage number for voltage multiplier to achieve maximum power conversion efficiency is discussed. Furthermore, according to the Bode-Fano criterion and the proposed model, a limitation on maximum power up range for passive UHF RFID power extraction circuits is also studied.

Experimental Investigation on Propagation Characteristics of PD Radiated UHF Signal in Actual 252 kV GIS

Directory of Open Access Journals (Sweden)

Tianhui Li

2017-07-01

Full Text Available For partial discharge (PD diagnostics in gas insulated switchgears (GISs based on the ultra-high-frequency (UHF method, it is essential to study the attenuation characteristics of UHF signals so as to improve the application of the UHF technique. Currently, the performance of UHF has not been adequately considered in most experimental research, while the constructive conclusions about the installation and position of UHF sensors are relatively rare. In this research, by using a previously-designed broadband sensor, the output signal is detected and analyzed experimentally in a 252 kV GIS with L-shaped structure and disconnecting switch. Since the relative position of the sensor and the defect is usually fixed by prior research, three circumferential angle positions of the defect in cross section are performed. The results are studied by time, statistics and frequency analyses. This identifies that the discontinuity conductor of DS will lead to a rise of both the peak to peak value (Vpp and the transmission rate of the UHF signal. Then, the frequency analysis indicates that the reason for the distinction of signal amplitude and transmission rate is that the mode components of the PD signal are distinctively affected by the special structure of GIS. Finally, the optimal circumferential angle position of the UHF Sensor is given based on the comparison of transmission rates.

The Capacitance and Temperature Effects of the SiC- and Si-Based MEMS Pressure Sensor

International Nuclear Information System (INIS)

Marsi, N; Majlis, B Y; Hamzah, A A; Mohd, F

2013-01-01

This project develops the pressure sensor for monitoring the extreme conditions inside the gas turbine engine. The capacitive-based instead of piezoresistive-based pressure sensor is employed to avoid temperature drift. The deflecting (top) plate and the fixed (bottom) plate generate the capacitance, which is proportional to the applied input pressure and temperature. Two thin film materials of four different sizes are employed for the top plate, namely cubic silicon carbide (3C-SiC) and silicon (Si). Their performances in term of the sensitivity and linearity of the capacitance versus pressure are simulated at the temperature of 27°C, 500°C, 700°C and 1000°C. The results show that both materials display linear characteristics for temperature up to 500°C, although SiC-based sensor shows higher sensitivity. However, when the temperatures are increased to 700°C and 1000°C, the Si- based pressure sensor starts to malfunction at 50 MPa. However, the SiC-based pressure sensor continues to demonstrate high sensitivity and linearity at such high temperature and pressure. This paper validates the need of employing silicon carbide instead of silicon for sensing of extreme environments.

Ionospheric Impacts on UHF Space Surveillance

Science.gov (United States)

Jones, J. C.

2017-12-01

Earth's atmosphere contains regions of ionized plasma caused by the interaction of highly energetic solar radiation. This region of ionization is called the ionosphere and varies significantly with altitude, latitude, local solar time, season, and solar cycle. Significant ionization begins at about 100 km (E layer) with a peak in the ionization at about 300 km (F2 layer). Above the F2 layer, the atmosphere is mostly ionized but the ion and electron densities are low due to the unavailability of neutral molecules for ionization so the density decreases exponentially with height to well over 1000 km. The gradients of these variations in the ionosphere play a significant role in radio wave propagation. These gradients induce variations in the index of refraction and cause some radio waves to refract. The amount of refraction depends on the magnitude and direction of the electron density gradient and the frequency of the radio wave. The refraction is significant at HF frequencies (3-30 MHz) with decreasing effects toward the UHF (300-3000 MHz) range. UHF is commonly used for tracking of space objects in low Earth orbit (LEO). While ionospheric refraction is small for UHF frequencies, it can cause errors in range, azimuth angle, and elevation angle estimation by ground-based radars tracking space objects. These errors can cause significant errors in precise orbit determinations. For radio waves transiting the ionosphere, it is important to understand and account for these effects. Using a sophisticated radio wave propagation tool suite and an empirical ionospheric model, we calculate the errors induced by the ionosphere in a simulation of a notional space surveillance radar tracking objects in LEO. These errors are analyzed to determine daily, monthly, annual, and solar cycle trends. Corrections to surveillance radar measurements can be adapted from our simulation capability.

Environmental/Noise Effects on VHF/UHF UWB SAR

National Research Council Canada - National Science Library

Ralston, James

1998-01-01

This paper presents a straightforward approach to estimating the impact of natural environmental noise on an overall system noise temperature for very high frequency/ultrahigh frequency synthetic aperture radar (VHF/UHF SAR...

Are tomorrow's micro-supercapacitors hidden in a forest of silicon nanotrees?

Science.gov (United States)

Thissandier, Fleur; Gentile, Pascal; Brousse, Thierry; Bidan, Gérard; Sadki, Saïd

2014-12-01

Silicon nanotrees (SiNTrs) have been grown by Chemical Vapor Deposition (CVD) via gold catalysis and a three steps process: trunks and branches growth are separated by a new gold catalyst deposition. The influence of growth conditions and the second gold catalyst deposition method on SiNTrs morphology are investigated. SiNTrs based electrodes show a capacitive behavior and better capacitance than the corresponding silicon nanowires (SiNWs) electrode. Electrode capacitance is increased up to 900 μF cm-2, i.e. 150 fold higher than for bulk silicon. Micro-supercapacitors with SiNTrs electrodes have a remarkable stability (only 1.2% loses of their initial capacitance after more than one million cycles). The use of an ionic liquid based electrolyte leads to a high maximum power density (around 225 mW cm-2) which is competitive with Onion Like Carbon based micro-supercapacitors.

Memory characteristics of silicon nitride with silicon nanocrystals as a charge trapping layer of nonvolatile memory devices

International Nuclear Information System (INIS)

Choi, Sangmoo; Yang, Hyundeok; Chang, Man; Baek, Sungkweon; Hwang, Hyunsang; Jeon, Sanghun; Kim, Juhyung; Kim, Chungwoo

2005-01-01

Silicon nitride with silicon nanocrystals formed by low-energy silicon plasma immersion ion implantation has been investigated as a charge trapping layer of a polycrystalline silicon-oxide-nitride-oxide-silicon-type nonvolatile memory device. Compared with the control sample without silicon nanocrystals, silicon nitride with silicon nanocrystals provides excellent memory characteristics, such as larger width of capacitance-voltage hysteresis, higher program/erase speed, and lower charge loss rate at elevated temperature. These improved memory characteristics are derived by incorporation of silicon nanocrystals into the charge trapping layer as additional accessible charge traps with a deeper effective trap energy level

3D capacitive tactile sensor using DRIE micromachining

Science.gov (United States)

Chuang, Chiehtang; Chen, Rongshun

2005-07-01

This paper presents a three dimensional micro capacitive tactile sensor that can detect normal and shear forces which is fabricated using deep reactive ion etching (DRIE) bulk silicon micromachining. The tactile sensor consists of a force transmission plate, a symmetric suspension system, and comb electrodes. The sensing character is based on the changes of capacitance between coplanar sense electrodes. High sensitivity is achieved by using the high aspect ratio interdigital electrodes with narrow comb gaps and large overlap areas. The symmetric suspension mechanism of this sensor can easily solve the coupling problem of measurement and increase the stability of the structure. In this paper, the sensor structure is designed, the capacitance variation of the proposed device is theoretically analyzed, and the finite element analysis of mechanical behavior of the structures is performed.

A Numerical Estimation of a RFID Reader Field and SAR inside a Blood Bag at UHF

Directory of Open Access Journals (Sweden)

Alessandro Fanti

2016-11-01

Full Text Available In this paper, the effects of UHF electromagnetic fields produced by a RFID reader on a blood bag are evaluated numerically in several configurations. The results of the simulation, field level and distribution, specific absorption rate (SAR, and heating time show that an exposure to a typical reader field leads to a temperature increase smaller than 0.1 C and to a SAR smaller than 1 W/kg. As a consequence, no adverse biological effects occur during a typical UHF RFID reading cycle on a blood bag. Therefore, the blood contained in a bag traced using UHF-RFID is as safe as those traced using barcodes. The proposed analysis supports the use of UHF RFID in the blood transfusion supply chain.

The Anti-RFI Design of Intelligent Electric Energy Meters with UHF RFID

Science.gov (United States)

Chen, Xiangqun; Huang, Rui; Shen, Liman; chen, Hao; Xiong, Dezhi; Xiao, Xiangqi; Liu, Mouhai; Xu, Renheng

2018-03-01

In order to solve the existing artificial meter reading watt-hour meter industry is still slow and inventory of common problems, using the uhf radio frequency identification (RFID) technology and intelligent watt-hour meter depth fusion, which has a one-time read multiple tags, identification distance, high transmission rate, high reliability, etc, while retaining the original asset management functions, in order to ensure the uhf RFID and minimum impact on the operation of the intelligent watt-hour meter, proposed to improve the stability of the electric meter system while working at the same time, this paper designs the uhf RFID intelligent watt-hour meter radio frequency interference resistance, put forward to improve intelligent watt-hour meter electromagnetic compatibility design train of thought, and introduced its power and the hardware circuit design of printed circuit board, etc.

Spiral silicon drift detectors

International Nuclear Information System (INIS)

Rehak, P.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Lutz, G.; Kemmer, J.; Prechtel, U.; Ziemann, T.

1988-01-01

An advanced large area silicon photodiode (and x-ray detector), called Spiral Drift Detector, was designed, produced and tested. The Spiral Detector belongs to the family of silicon drift detectors and is an improvement of the well known Cylindrical Drift Detector. In both detectors, signal electrons created in silicon by fast charged particles or photons are drifting toward a practically point-like collection anode. The capacitance of the anode is therefore kept at the minimum (0.1pF). The concentric rings of the cylindrical detector are replaced by a continuous spiral in the new detector. The spiral geometry detector design leads to a decrease of the detector leakage current. In the spiral detector all electrons generated at the silicon-silicon oxide interface are collected on a guard sink rather than contributing to the detector leakage current. The decrease of the leakage current reduces the parallel noise of the detector. This decrease of the leakage current and the very small capacities of the detector anode with a capacitively matched preamplifier may improve the energy resolution of Spiral Drift Detectors operating at room temperature down to about 50 electrons rms. This resolution is in the range attainable at present only by cooled semiconductor detectors. 5 refs., 10 figs

Profiling of barrier capacitance and spreading resistance using a transient linearly increasing voltage technique.

Science.gov (United States)

Gaubas, E; Ceponis, T; Kusakovskij, J

2011-08-01

A technique for the combined measurement of barrier capacitance and spreading resistance profiles using a linearly increasing voltage pulse is presented. The technique is based on the measurement and analysis of current transients, due to the barrier and diffusion capacitance, and the spreading resistance, between a needle probe and sample. To control the impact of deep traps in the barrier capacitance, a steady state bias illumination with infrared light was employed. Measurements of the spreading resistance and barrier capacitance profiles using a stepwise positioned probe on cross sectioned silicon pin diodes and pnp structures are presented.

Three dimensional simulated modelling of diffusion capacitance of ...

African Journals Online (AJOL)

A three dimensional (3-D) simulated modelling was developed to analyse the excess minority carrier density in the base of a polycrystalline bifacial silicon solar cell. The concept of junction recombination velocity was ado-pted to quantify carrier flow through the junction, and to examine the solar cell diffusion capacitance for ...

Inkjet printing of UHF antennas on corrugated cardboards for packaging applications

Energy Technology Data Exchange (ETDEWEB)

Sowade, Enrico, E-mail: enrico.sowade@mb.tu-chemnitz.de [Digital Printing and Imaging Technology, Technische Universität Chemnitz, Chemnitz (Germany); Göthel, Frank [Digital Printing and Imaging Technology, Technische Universität Chemnitz, Chemnitz (Germany); Zichner, Ralf [Department Printed Functionalities, Fraunhofer Institute for Electronic Nano Systems (ENAS), Chemnitz (Germany); Baumann, Reinhard R. [Digital Printing and Imaging Technology, Technische Universität Chemnitz, Chemnitz (Germany); Department Printed Functionalities, Fraunhofer Institute for Electronic Nano Systems (ENAS), Chemnitz (Germany)

2015-03-30

Highlights: • Inkjet printing of UHF antennas on cardboard substrates. • Development of primer layer to compensate the absorptiveness of the cardboard and the rough surface. • Manufacturing of UHF antennas in a fully digital manner for packaging applications. - Abstract: In this study, a method based on inkjet printing has been established to develop UHF antennas on a corrugated cardboard for packaging applications. The use of such a standardized, paper-based packaging substrate as material for printing electronics is challenging in terms of its high surface roughness and high ink absorption rate, especially when depositing very thin films with inkjet printing technology. However, we could obtain well-defined silver layers on the cardboard substrates due to a primer layer approach. The primer layer is based on a UV-curable ink formulation and deposited as well as the silver ink with inkjet printing technology. Industrial relevant printheads were chosen for the deposition of the materials. The usage of inkjet printing allows highest flexibility in terms of pattern design. The primer layer was proven to optimize the surface characteristics of the substrate, mainly reducing the surface roughness and water absorptiveness. Thanks to the primer layer approach, ultra-high-frequency (UHF) radio-frequency identification (RFID) antennas were deposited by inkjet printing on the corrugated cardboards. Along with the characterization and interpretation of electrical properties of the established conductive antenna patterns, the performance of the printed antennas were analyzed in detail by measuring the scattering parameter S{sub 11} and the antenna gain.

Solar Cell Capacitance Determination Based on an RLC Resonant Circuit

Directory of Open Access Journals (Sweden)

Petru Adrian Cotfas

2018-03-01

Full Text Available The capacitance is one of the key dynamic parameters of solar cells, which can provide essential information regarding the quality and health state of the cell. However, the measurement of this parameter is not a trivial task, as it typically requires high accuracy instruments using, e.g., electrical impedance spectroscopy (IS. This paper introduces a simple and effective method to determine the electric capacitance of the solar cells. An RLC (Resistor Inductance Capacitor circuit is formed by using an inductor as a load for the solar cell. The capacitance of the solar cell is found by measuring the frequency of the damped oscillation that occurs at the moment of connecting the inductor to the solar cell. The study is performed through simulation based on National Instruments (NI Multisim application as SPICE simulation software and through experimental capacitance measurements of a monocrystalline silicon commercial solar cell and a photovoltaic panel using the proposed method. The results were validated using impedance spectroscopy. The differences between the capacitance values obtained by the two methods are of 1% for the solar cells and of 9.6% for the PV panel. The irradiance level effect upon the solar cell capacitance was studied obtaining an increase in the capacitance in function of the irradiance. By connecting different inductors to the solar cell, the frequency effect upon the solar cell capacitance was studied noticing a very small decrease in the capacitance with the frequency. Additionally, the temperature effect over the solar cell capacitance was studied achieving an increase in capacitance with temperature.

Compact broadband circularly polarised slot antenna for universal UHF RFID readers

DEFF Research Database (Denmark)

Xu, Bo; Zhang, Shuai; Liu, Yusha

2015-01-01

A compact broadband circularly polarised (CP) slot antenna is designed for universal ultra-high-frequency (UHF) radio frequency identification (RFID) readers. The antenna consists of an L-shaped metal strip and a square-slot-loaded ground plane with four tuning stubs. The total size is 100 mm×100mm......×1.6 mm. The measured –10 dB impedance bandwidth is 40.7% (772–1166 MHz) and the measured 3 dB axial ratio (AR) bandwidth is 13.9% (840–965 MHz). Both the impedance and AR bandwidth cover the worldwide UHF RFID band....

High-performance RF coil inductors on silicon

Energy Technology Data Exchange (ETDEWEB)

Malba, V.; Young, D.; Ou, J.J.; Bernhardt, A.F.; Boser, B.E.

1998-03-01

Strong demand for wireless communication devices has motivated research directed toward monolithic integration of transceivers. The fundamental electronic component least compatible with silicon integrated circuits is the inductor, although a number of inductors are required to implement oscillators, filters and matching networks in cellular devices. Spiral inductors have been integrated into the silicon IC metallization sequence but have not performed adequately due to coupling to the silicon which results in parasitic capacitance and loss. We have, for the first time, fabricated three dimensional coil inductors on silicon which have significantly lower capacitive coupling and loss and which now exceed the requirements of potential applications. Quality factors of 30 at 1 GHz have been measured in single turn devices and Q > 16 in 2 and 4 turn devices. The reduced Q for multiturn devices appears to be related to eddy currents in outer turns generated by magnetic fields from current in neighboring turns. Higher Q values significantly in excess of 30 are anticipated using modified coil designs.

Increased operational range for implantable UHF RFID antennas

NARCIS (Netherlands)

Dubok, A.; Smolders, A.B.

2014-01-01

This paper discusses the main design challenges of implantable UHF RFID antennas in lossy environments. A novel cylindrical implantable antenna concept is presented. The proposed antenna shows good performance inside lossy environments, like a human body. The RFID tag is able to work in a range up

Touch-mode capacitive pressure sensor with graphene-polymer heterostructure membrane

Science.gov (United States)

Berger, Christian; Phillips, Rory; Pasternak, Iwona; Sobieski, Jan; Strupinski, Wlodek; Vijayaraghavan, Aravind

2018-01-01

We describe the fabrication and characterisation of a touch-mode capacitive pressure sensor (TMCPS) with a robust design that comprises a graphene-polymer heterostructure film, laminated onto the silicon dioxide surface of a silicon wafer, incorporating a SU-8 spacer grid structure. The spacer grid structure allows the flexible graphene-polymer film to be partially suspended above the substrate, such that a pressure on the membrane results in a reproducible deflection, even after exposing the membrane to pressures over 10 times the operating range. Sensors show reproducible pressure transduction in water submersion at varying depths under static and dynamic loading. The measured capacitance change in response to pressure is in good agreement with an analytical model of clamped plates in touch mode. The device shows a pressure sensitivity of 27.1 +/- 0.5 fF Pa-1 over a pressure range of 0.5 kPa-8.5 kPa. In addition, we demonstrate the operation of this device as a force-touch sensor in air.

TOSCA simulation of some effects observed in irradiated silicon detectors

International Nuclear Information System (INIS)

Moszczynski, A.S.

2001-12-01

TOSCA package has been used to simulate some effects observed recently in heavily irradiated silicon detectors. In particular, unexpected possibility of α-particle registration at p+ contact has been explained without presented elsewhere assumption that there was p-n junction of unknown origin beneath p+ layer. Performed simulations showed that assumption on relaxation-like character of irradiated silicon material is also not necessary to explain such effects like low-voltage capacitance peak in reverse bias and negative capacitance in forward bias. (author)

A signature correlation study of ground target VHF/UHF ISAR imagery

Science.gov (United States)

Gatesman, Andrew J.; Beaudoin, Christopher J.; Giles, Robert H.; Kersey, William T.; Waldman, Jerry; Carter, Steve; Nixon, William E.

2003-09-01

VV and HH-polarized radar signatures of several ground targets were acquired in the VHF/UHF band (171-342 MHz) by using 1/35th scale models and an indoor radar range operating from 6 to 12 GHz. Data were processed into medianized radar cross sections as well as focused, ISAR imagery. Measurement validation was confirmed by comparing the radar cross section of a test object with a method of moments radar cross section prediction code. The signatures of several vehicles from three vehicle classes (tanks, trunks, and TELs) were measured and a signature cross-correlation study was performed. The VHF/UHF band is currently being exploited for its foliage penetration ability, however, the coarse image resolution which results from the relatively long radar wavelengths suggests a more challenging target recognition problem. One of the study's goals was to determine the amount of unique signature content in VHF/UHF ISAR imagery of military ground vehicles. Open-field signatures are compared with each other as well as with simplified shapes of similar size. Signatures were also acquired on one vehicle in a variety of configurations to determine the impact of monitor target variations on the signature content at these frequencies.

RTD application in low power UHF rectifiers

International Nuclear Information System (INIS)

Sinyakin, V Yu; Makeev, M O; Meshkov, S A

2016-01-01

In the current work, the problem of UHF RFID passive tag sensitivity increase is considered. Tag sensitivity depends on HF signal rectifier efficiency and antenna-rectifier impedance matching. Possibility of RFID passive tag sensitivity increase up to 10 times by means of RTD use in HF signal rectifier in comparison with tags based on Schottky barrier diode is shown. (paper)

Finite-element simulations of coupling capacitances in capacitively coupled pixel detectors

CERN Document Server

AUTHOR|(SzGeCERN)755510

2017-01-01

Capacitively coupled hybrid silicon pixel-detector assemblies are under study for the vertex detector at the proposed future CLIC linear electron-positron collider. The assemblies consist of active CCPDv3 sensors, with 25 μm pixel pitch implemented in a 180 nm High- Voltage CMOS process, which are glued to the CLICpix readout ASIC, with the same pixel pitch and processed in a commercial 65 nm CMOS technology. The signal created in the silicon bulk of the active sensors passes a two-stage amplifier, in each pixel, and gets transferred as a voltage pulse to metal pads facing the readout chip (ROC). The coupling of the signal to the metal pads on the ROC side proceeds through the capacitors formed between the two chips by a thin layer of epoxy glue. The coupling strength and the amount of unwanted cross coupling to neighbouring pixels depends critically on the uniformity of the glue layer, its thickness and on the alignment precision during the flip-chip assembly process. Finite-element calculations of the coup...

Characterizing the effects of free carriers in fully etched, dielectric-clad silicon waveguides

Science.gov (United States)

Sharma, Rajat; Puckett, Matthew W.; Lin, Hung-Hsi; Vallini, Felipe; Fainman, Yeshaiahu

2015-06-01

We theoretically characterize the free-carrier plasma dispersion effect in fully etched silicon waveguides, with various dielectric material claddings, due to fixed interface charges and trap states at the silicon-dielectric interfaces. The values used for these charges are obtained from the measured capacitance-voltage characteristics of SiO2, SiNx, and Al2O3 thin films deposited on silicon substrates. The effect of the charges on the properties of silicon waveguides is then calculated using the semiconductor physics tool Silvaco in combination with the finite-difference time-domain method solver Lumerical. Our results show that, in addition to being a critical factor in the analysis of such active devices as capacitively driven silicon modulators, this effect should also be taken into account when considering the propagation losses of passive silicon waveguides.

Special Semaphore Scheme for UHF Spacecraft Communications

Science.gov (United States)

Butman, Stanley; Satorius, Edgar; Ilott, Peter

2006-01-01

A semaphore scheme has been devised to satisfy a requirement to enable ultrahigh- frequency (UHF) radio communication between a spacecraft descending from orbit to a landing on Mars and a spacecraft, in orbit about Mars, that relays communications between Earth and the lander spacecraft. There are also two subsidiary requirements: (1) to use UHF transceivers, built and qualified for operation aboard the spacecraft that operate with residual-carrier binary phase-shift-keying (BPSK) modulation at a selectable data rate of 8, 32, 128, or 256 kb/s; and (2) to enable low-rate signaling even when received signals become so weak as to prevent communication at the minimum BPSK rate of 8 kHz. The scheme involves exploitation of Manchester encoding, which is used in conjunction with residual-carrier modulation to aid the carrier-tracking loop. By choosing various sequences of 1s, 0s, or 1s alternating with 0s to be fed to the residual-carrier modulator, one would cause the modulator to generate sidebands at a fundamental frequency of 4 or 8 kHz and harmonics thereof. These sidebands would constitute the desired semaphores. In reception, the semaphores would be detected by a software demodulator.

Thin film silicon by a microwave plasma deposition technique: Growth and devices, and, interface effects in amorphous silicon/crystalline silicon solar cells

Science.gov (United States)

Jagannathan, Basanth

Thin film silicon (Si) was deposited by a microwave plasma CVD technique, employing double dilution of silane, for the growth of low hydrogen content Si films with a controllable microstructure on amorphous substrates at low temperatures (prepared by this technique. Such films showed a dark conductivity ˜10sp{-6} S/cm, with a conduction activation energy of 0.49 eV. Film growth and properties have been compared for deposition in Ar and He carrier systems and growth models have been proposed. Low temperature junction formation by undoped thin film silicon was examined through a thin film silicon/p-type crystalline silicon heterojunctions. The thin film silicon layers were deposited by rf glow discharge, dc magnetron sputtering and microwave plasma CVD. The hetero-interface was identified by current transport analysis and high frequency capacitance methods as the key parameter controlling the photovoltaic (PV) response. The effect of the interface on the device properties (PV, junction, and carrier transport) was examined with respect to modifications created by chemical treatment, type of plasma species, their energy and film microstructure interacting with the substrate. Thermally stimulated capacitance was used to determine the interfacial trap parameters. Plasma deposition of thin film silicon on chemically clean c-Si created electron trapping sites while hole traps were seen when a thin oxide was present at the interface. Under optimized conditions, a 10.6% efficient cell (11.5% with SiOsb2 A/R) with an open circuit voltage of 0.55 volts and a short circuit current density of 30 mA/cmsp2 was fabricated.

Experimental Study on Inkjet-Printed Passive UHF RFID Tags on Versatile Paper-Based Substrates

Directory of Open Access Journals (Sweden)

Han He

2016-01-01

Full Text Available We present the possibilities and challenges of passive UHF RFID tag antennas manufactured by inkjet printing silver nanoparticle ink on versatile paper-based substrates. The most efficient manufacturing parameters, such as the pattern resolution, were determined and the optimal number of printed layers was evaluated for each substrate material. Next, inkjet-printed passive UHF RFID tags were fabricated on each substrate with the optimized parameters and number of layers. According to our measurements, the tags on different paper substrates showed peak read ranges of 4–6.5 meters and the tags on different cardboard substrates exhibited peak read ranges of 2–6 meters. Based on their wireless performance, these inkjet-printed paper-based passive UHF RFID tags are sufficient for many future wireless applications and comparable to tags fabricated on more traditional substrates, such as polyimide.

From VHF to UHF CMOS-MEMS Monolithically Integrated Resonators

DEFF Research Database (Denmark)

Teva, Jordi; Berini, Abadal Gabriel; Uranga, A.

2008-01-01

This paper presents the design, fabrication and characterization of microresonators exhibiting resonance frequencies in the VHF and UHF bands, fabricated using the available layers of the standard and commercial CMOS technology, AMS-0.35mum. The resonators are released in a post-CMOS process cons...

HF RFID versus UHF RFID--Technology for Library Service Transformation at City University of Hong Kong

Science.gov (United States)

Ching, Steve H.; Tai, Alice

2009-01-01

Since libraries first used RFID systems in the late 1990s, more and more libraries have identified the advantages of the technology. With advances in HF and UHF RFID, both alternatives are now viable in library applications. While some librarians are still skeptical towards UHF RFID as unproven in the library arena, the City University of Hong…

Assessment of Multipath and Shadowing Effects on UHF Band in ...

African Journals Online (AJOL)

Sultan

bands are used for television broadcasting, mobile cellular systems, Wi-Fi, satellite communications and many others. Effective communication link in the UHF band requires direct line of sight ..... ad-hoc 802.11 wireless LAN (WLAN) devices.

Effect of hysteretic and non-hysteretic negative capacitance on tunnel FETs DC performance

Science.gov (United States)

Saeidi, Ali; Jazaeri, Farzan; Stolichnov, Igor; Luong, Gia V.; Zhao, Qing-Tai; Mantl, Siegfried; Ionescu, Adrian M.

2018-03-01

This work experimentally demonstrates that the negative capacitance effect can be used to significantly improve the key figures of merit of tunnel field effect transistor (FET) switches. In the proposed approach, a matching condition is fulfilled between a trained-polycrystalline PZT capacitor and the tunnel FET (TFET) gate capacitance fabricated on a strained silicon-nanowire technology. We report a non-hysteretic switch configuration by combining a homojunction TFET and a negative capacitance effect booster, suitable for logic applications, for which the on-current is increased by a factor of 100, the transconductance by 2 orders of magnitude, and the low swing region is extended. The operation of a hysteretic negative capacitance TFET, when the matching condition for the negative capacitance is fulfilled only in a limited region of operation, is also reported and discussed. In this late case, a limited improvement in the device performance is observed. Overall, the paper demonstrates the main beneficial effects of negative capacitance on TFETs are the overdrive and transconductance amplification, which exactly address the most limiting performances of current TFETs.

Supercapacitor electrodes based on polyaniline-silicon nanoparticle composite

Energy Technology Data Exchange (ETDEWEB)

Liu, Qiang; Yau, Siu-Tung [Department of Electrical and Computer Engineering, Cleveland State University, 2121 Euclid Avenue, Cleveland, OH 44115 (United States); Nayfeh, Munir H. [Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

2010-06-15

A composite material formed by dispersing ultrasmall silicon nanoparticles in polyaniline has been used as the electrode material for supercapacitors. Electrochemical characterization of the composite indicates that the nanoparticles give rise to double-layer capacitance while polyaniline produces pseudocapacitance. The composite shows significantly improved capacitance compared to that of polyaniline. The enhanced capacitance results in high power (220 kW kg{sup -1}) and energy-storage (30 Wh kg{sup -1}) capabilities of the composite material. A prototype supercapacitor using the composite as the charge storage material has been constructed. The capacitor showed the enhanced capacitance and good device stability during 1000 charging/discharging cycles. (author)

Poly-silicon quantum-dot single-electron transistors

International Nuclear Information System (INIS)

Kang, Kwon-Chil; Lee, Joung-Eob; Lee, Jung-Han; Lee, Jong-Ho; Shin, Hyung-Cheol; Park, Byung-Gook

2012-01-01

For operation of a single-electron transistors (SETs) at room temperature, we proposed a fabrication method for a SET with a self-aligned quantum dot by using polycrystalline silicon (poly-Si). The self-aligned quantum dot is formed by the selective etching of a silicon nanowire on a planarized surface and the subsequent deposition and etch-back of poly-silicon or chemical mechanical polishing (CMP). The two tunneling barriers of the SET are fabricated by thermal oxidation. Also, to decrease the leakage current and control the gate capacitance, we deposit a hard oxide mask layer. The control gate is formed by using an electron beam and photolithography on chemical vapor deposition (CVD). Owing to the small capacitance of the narrow control gate due to the tetraethyl orthosilicate (TEOS) hard mask, we observe clear Coulomb oscillation peaks and differential trans-conductance curves at room temperature. The clear oscillation period of the fabricated SET is 2.0 V.

Ultrahigh Temperature Capacitive Pressure Sensor

Science.gov (United States)

Harsh, Kevin

2014-01-01

Robust, miniaturized sensing systems are needed to improve performance, increase efficiency, and track system health status and failure modes of advanced propulsion systems. Because microsensors must operate in extremely harsh environments, there are many technical challenges involved in developing reliable systems. In addition to high temperatures and pressures, sensing systems are exposed to oxidation, corrosion, thermal shock, fatigue, fouling, and abrasive wear. In these harsh conditions, sensors must be able to withstand high flow rates, vibration, jet fuel, and exhaust. In order for existing and future aeropropulsion turbine engines to improve safety and reduce cost and emissions while controlling engine instabilities, more accurate and complete sensor information is necessary. High-temperature (300 to 1,350 C) capacitive pressure sensors are of particular interest due to their high measurement bandwidth and inherent suitability for wireless readout schemes. The objective of this project is to develop a capacitive pressure sensor based on silicon carbon nitride (SiCN), a new class of high-temperature ceramic materials, which possesses excellent mechanical and electric properties at temperatures up to 1,600 C.

Characterization of inkjet-printing HF and UHF antennas for RFID applications

Science.gov (United States)

Tarapata, Grzegorz; Paczesny, Daniel; Kawecki, Krzysztof

2013-10-01

The aim of this work was to perform a set of RFID antennas on flexible plastic substrates designed for range of HF and UHF band. The samples was fabricated using inkjet printing technology and conductive material base on silver nanopartilces ink. Fabricated antennas have been characterized, and the results were compared with the parameters of antennas made with usage of classical PCB technology on FR4 laminate with copper metallization. The paper presents studies on the impact of elastic substrates and conductive materials on antennas electrical parameters, as well as the communication range of the resulting RFID tags. During the experiment two patterns of HF and three patterns of UHF antennas was examined and the antennas was realized on different types of substrates, such as PET, Kapton® and FR4.

Sputtered Encapsulation as Wafer Level Packaging for Isolatable MEMS Devices: A Technique Demonstrated on a Capacitive Accelerometer

Directory of Open Access Journals (Sweden)

Azrul Azlan Hamzah

2008-11-01

Full Text Available This paper discusses sputtered silicon encapsulation as a wafer level packaging approach for isolatable MEMS devices. Devices such as accelerometers, RF switches, inductors, and filters that do not require interaction with the surroundings to function, could thus be fully encapsulated at the wafer level after fabrication. A MEMSTech 50g capacitive accelerometer was used to demonstrate a sputtered encapsulation technique. Encapsulation with a very uniform surface profile was achieved using spin-on glass (SOG as a sacrificial layer, SU-8 as base layer, RF sputtered silicon as main structural layer, eutectic gold-silicon as seal layer, and liquid crystal polymer (LCP as outer encapsulant layer. SEM inspection and capacitance test indicated that the movable elements were released after encapsulation. Nanoindentation test confirmed that the encapsulated device is sufficiently robust to withstand a transfer molding process. Thus, an encapsulation technique that is robust, CMOS compatible, and economical has been successfully developed for packaging isolatable MEMS devices at the wafer level.

Four-channel readout ASIC for silicon pad detectors

International Nuclear Information System (INIS)

Baturitsky, M.A.; Zamiatin, N.I.

2000-01-01

A custom front-end readout ASIC has been designed for silicon calorimeters supposed to be used in high-energy physics experiments. The ASIC was produced using BJT-JFET technology. It contains four channels of a fast low-noise charge-sensitive preamplifier (CSP) with inverting outputs summed by a linear adder (LA) followed by an RC-CR shaping amplifier (SA) with 30 ns peaking time. Availability of separate outputs of the CSPs and the LA makes it possible to join any number of silicon detector layers to obtain the longitudinal and transversal resolution required using only this ASIC in any silicon calorimeter minitower configuration. Noise performance is ENC=1800e - +18e - /pF at 30 ns peaking time for detector capacitance up to C d =400 pF. Rise time is 8 ns at input capacitance C d =100 pF. Power dissipation is less than 50 mW/ chip at voltage supply 5 V

Study of the frequency modulation of various U.H.F. signals occurring in a linear electron accelerator; Etude de la modulation de frequence de divers signaux U.H.F. existant dans un accelerateur lineaire d'electrons

Energy Technology Data Exchange (ETDEWEB)

Bergere, R; Veyssiere, A; Daujat, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1966-06-01

This paper contains a digest of a series of studies on the frequency modulation of U.H.F. fields and signals associated with the linear electron accelerator at Saclay. We first consider the frequency modulation of a U. H. F. pulse before its injection into an accelerating structure and after its subsequent propagation when no accelerated electrons are present. We then apply a similar analysis to the frequency modulation due to the direct interaction of the electron beam itself, and the accelerating U.H.F. fields. Finally we consider the phase modulation of the elementary electron packet itself. This phase modulation can be correctly interpreted by considering the dynamics of the electron beam as such. This analysis moreover, gives a correct interpretation of the evolution of the phase modulation with time, as the elementary electron packets move along with the sinusoidal U.H.F. accelerating fields. (authors) [French] Cet article resume les etudes faites sur l'accelerateur lineaire d'electrons de Saclay a propos de la modulation de frequence des divers signaux U.H.F. presents autour de l'accelerateur. On etudie d'abord la modulation de frequence des impulsions U.H.F. entrant sur la structure acceleratrice ou transmises par cette structure en l'absence de faisceau d'electrons acceleres. On analyse ensuite la modulation de frequence resultant de l'interaction d'une de ces ondes avec le faisceau d'electrons acceleres. On etudie enfin, la modulation de phase des divers paquets elementaires constituant une impulsion d'electrons acceleres. On montre comment cette modulation de phase peut s'expliquer par des considerations sur la dynamique du faisceau et conduire a une representation dans les divers cas possibles de l'evolution de la phase d'accrochage des electrons sur l'onde sinusoidale progressive de champ accelerateur. (auteurs)

Assessment of multipath and shadowing effects on UHF band in ...

African Journals Online (AJOL)

In this work, the multi-path and shadowing effects on signal impairment were investigated through the use of empirical and semi-empirical path loss models analysis in built-up environments. Electromagnetic field strength measurements were conducted using four television transmitters at UHF bands along four major routes ...

Three-axial force sensor with capacitive read-out using a differential relaxation oscillator

NARCIS (Netherlands)

Brookhuis, Robert Anton; Wiegerink, Remco J.; Lammerink, Theodorus S.J.; Krijnen, Gijsbertus J.M.

2013-01-01

A silicon three-axis force sensor is designed and realized to be used for measurement of the interaction force between a human finger and the environment. To detect the force components, a capacitive read-out system using a novel relaxation oscillator has been developed with an output frequency

Detection of moving humans in UHF wideband SAR

Science.gov (United States)

Sjögren, Thomas K.; Ulander, Lars M. H.; Frölind, Per-Olov; Gustavsson, Anders; Stenström, Gunnar; Jonsson, Tommy

2014-06-01

In this paper, experimental results for UHF wideband SAR imaging of humans on an open field and inside a forest is presented. The results show ability to detect the humans and suggest possible ways to improve the results. In the experiment, single channel wideband SAR mode of the UHF UWB system LORA developed by Swedish Defence Research Agency (FOI). The wideband SAR mode used in the experiment was from 220 to 450 MHz, thus with a fractional bandwidth of 0.68. Three humans walking and one stationary were available in the scene with one of the walking humans in the forest. The signature of the human in the forest appeared on the field, due to azimuth shift from the positive range speed component. One human on the field and the one in the forest had approximately the same speed and walking direction. The signatures in the SAR image were compared as a function of integration time based on focusing using the average relative speed of these given by GPS logs. A signal processing gain was obtained for the human in forest until approximately 15 s and 35 s for the human on the field. This difference is likely explained by uneven terrain and trees in the way, causing a non-straight walking path.

Development and analysis of a capacitive touch sensor using a liquid metal droplet

International Nuclear Information System (INIS)

Baek, Seungbum; Won, Dong-Joon; Kim, Joong Gil; Kim, Joonwon

2015-01-01

In this paper, we introduce a small-sized capacitive touch sensor with large variations in its capacitance. This sensor uses the changes in capacitance caused by the variation of the overlap area between a liquid metal (LM) droplet and a flat electrode while keeping the gap between the droplet and the bottom electrode at a small constant value (i.e. thickness of dielectric layer). Initially, the droplet is placed inside a polydimethylsiloxane (PDMS) chamber, and a thin silicon dioxide film separates the droplet and the electrode. Owing to the high surface tension of the LM, the droplet retains its spherical shape and the overlap area remains small, which means that the capacitance between the droplet and the electrode also remains small. When normal force is applied, the pressure on the membrane pushes the droplet downward, thus spreading the droplet to the bottom of the chamber and increasing the capacitance. To verify our concept, we performed theoretical analyses and experiments using a 2 mm  ×  2 mm  ×  2 mm 1-cell touch sensor. Finally, we obtained a capacitance variation of ∼30 pF by applying forces between 0 N and 1 N. (paper)

Nonlinear Parasitic Capacitance Modelling of High Voltage Power MOSFETs in Partial SOI Process

DEFF Research Database (Denmark)

Fan, Lin; Knott, Arnold; Jørgensen, Ivan Harald Holger

2016-01-01

: off-state, sub-threshold region, and on-state in the linear region. A high voltage power MOSFET is designed in a partial Silicon on Insulator (SOI) process, with the bulk as a separate terminal. 3D plots and contour plots of the capacitances versus bias voltages for the transistor summarize...

The use of large area silicon sensors for thermal neutron detection

International Nuclear Information System (INIS)

Schulte, R.L.; Swanson, F.; Kesselman, M.

1994-01-01

The use of large area planar silicon detectors coupled with gadolinium foils has been investigated to develop a thermal neutron detector having a large area-efficiency (Aε) product. Noise levels due to high detector capacitance limit the size of silicon detectors that can be utilized. Calculations using the Monte Carlo code, MCNP, have been made to determine the variation of intrinsic detection efficiency as a function of the discriminator threshold level required to eliminate the detector noise. Measurements of the noise levels for planar silicon detectors of various resistivities (400, 3000 and 5000 Ω cm) have been made and the optimal detector area-efficiency products have been determined. The response of a Si-Gd-Si sandwich detector with areas between 1 cm 2 and 10.5 cm 2 is presented and the effects of the detector capacitance and reverse current are discussed. ((orig.))

Investigation of the impact of mechanical stress on the properties of silicon strip sensors

CERN Document Server

Affolder, Tony; The ATLAS collaboration

2017-01-01

The new ATLAS tracker for phase II will be composed of silicon pixel and strip sensor modules. The strip sensor module consists of silicon sensors, boards and readout chips. Adhesives are used to connect the modular components thermally and mechanically. It was shown that the silicon sensor is exposed to mechanical stress, due to temperature difference between construction and operation. Mechanical stress can damage the sensor and can change the electrical properties. The thermal induced tensile stress near to the surface of a silicon sensor in a module was simulated and the results are compared to a cooled module. A four point bending setup was used to measure the maximum tensile stress of silicon detectors and to verify the piezoresistive effects on two recent development sensor types used in ATLAS (ATLAS07 and ATLAS12). Changes in the interstrip, bulk and bias resistance and capacitance as well as the coupling capacitance and the implant resistance were measured. The Leakage current was observed to decreas...

A Compact RFID Reader Antenna for UHF Near-Field and Far-Field Operations

Directory of Open Access Journals (Sweden)

Lai Xiao zheng

2013-01-01

Full Text Available A compact loop antenna is presented for mobile ultrahigh frequency (UHF radio frequency identification (RFID application. This antenna, printed on a 0.8 mm thick FR4 substrate with a small size of 31 mm × 31 mm, achieves good impedance bandwidth from 897 to 928 MHz, which covers USA RFID Band (902–928 MHz. The proposed loop configuration, with a split-ring resonator (SRR coupled inside it, demonstrates strong and uniform magnetic field distribution in the near-field antenna region. Its linearly polarized radiation pattern provides available far-field gain. Finally, the reading capabilities of antenna are up to 56 mm for near-field and 1.05 m for far-field UHF RFID operations, respectively.

Multiplication in Silicon p-n Junctions

DEFF Research Database (Denmark)

Moll, John L.

1965-01-01

Multiplication values were measured in the collector junctions of silicon p-n-p and n-p-n transistors before and after bombardment by 1016 neutrons/cm2. Within experimental error there was no change either in junction fields, as deduced from capacitance measurements, or in multiplication values i...

Silicon drift detectors with on-chip electronics for x-ray spectroscopy.

Science.gov (United States)

Fiorini, C; Longoni, A; Hartmann, R; Lechner, P; Strüder, L

1997-01-01

The silicon drift detector (SDD) is a semiconductor device based on high resistivity silicon fully depleted through junctions implanted on both sides of the semiconductor wafer. The electrons generated by the ionizing radiation are driven by means of a suitable electric field from the point of interaction toward a collecting anode of small capacitance, independent of the active area of the detector. A suitably designed front-end JFET has been directly integrated on the detector chip close to the anode region, in order to obtain a nearly ideal capacitive matching between detector and transistor and to minimize the stray capacitances of the connections. This feature allows it to reach high energy resolution also at high count rates and near room temperature. The present work describes the structure and the performance of SDDs specially designed for high resolution spectroscopy with soft x rays at high detection rate. Experimental results of SDDs used in spectroscopy applications are also reported.

The use of large area silicon sensors for thermal neutron detection

Energy Technology Data Exchange (ETDEWEB)

Schulte, R.L. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States)); Swanson, F. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States)); Kesselman, M. (Research and Development Center, Mail Stop: A01-26, Grumman Aerospace Corporation, Bethpage, NY 11714 (United States))

1994-12-30

The use of large area planar silicon detectors coupled with gadolinium foils has been investigated to develop a thermal neutron detector having a large area-efficiency (A[epsilon]) product. Noise levels due to high detector capacitance limit the size of silicon detectors that can be utilized. Calculations using the Monte Carlo code, MCNP, have been made to determine the variation of intrinsic detection efficiency as a function of the discriminator threshold level required to eliminate the detector noise. Measurements of the noise levels for planar silicon detectors of various resistivities (400, 3000 and 5000 [Omega] cm) have been made and the optimal detector area-efficiency products have been determined. The response of a Si-Gd-Si sandwich detector with areas between 1 cm[sup 2] and 10.5 cm[sup 2] is presented and the effects of the detector capacitance and reverse current are discussed. ((orig.))

Additive advantage in characteristics of MIMCAPs on flexible silicon (100) fabric with release-first process

KAUST Repository

Ghoneim, Mohamed T.

2013-11-20

We report the inherent increase in capacitance per unit planar area of state-of-the art high-κ integrated metal/insulator/metal capacitors (MIMCAPs) fabricated on flexible silicon fabric with release-first process. We methodically study and show that our approach to transform bulk silicon (100) into a flexible fabric adds an inherent advantage of enabling higher integration density dynamic random access memory (DRAM) on the same chip area. Our approach is to release an ultra-thin silicon (100) fabric (25 μm thick) from the bulk silicon wafer, then build MIMCAPs using sputtered aluminium electrodes and successive atomic layer depositions (ALD) without break-ing the vacuum of a high-κ aluminium oxide sandwiched between two tantalum nitride layers. This result shows that we can obtain flexible electronics on silicon without sacrificing the high density integration aspects and also utilize the non-planar geometry associated with fabrication process to obtain a higher integration density compared to bulk silicon integration due to an increased normalized capacitance per unit planar area. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Disturbances in VHF/UHF telemetry links as a possible effect of the 2003 Hokkaido Tokachi-oki earthquake

Directory of Open Access Journals (Sweden)

H. Nagamoto

2008-08-01

Full Text Available The data on radio telemetry links (for water information at VHF/UHF in Hokkaido are used to investigate the rate of disturbances on radio links (or connection failure and its association with a huge earthquake, Tokachi-oki earthquake on 26 September 2003. Especially, the telemetry links at the Tokachi region closest to the earthquake epicenter, showed a significant increase in disturbances on radio links two weeks to a few days before the earthquake on the basis of analysis during a long interval from 1 June 2002 to 3 November 2007 (over 5 years. We suggest that these severe disturbances in VHF/UHF telemetry links are attributed to the generation of seismogenic VHF/UHF radio noises (emissions. Based on this idea, we have estimated that the intensity of these seismogenic emissions is on the order of 10–19 dB μV/m. Finally, the present result was compared with other physical parameters already obtained for this earthquake.

Pulse power applications of silicon diodes in EML capacitive pulsers

Science.gov (United States)

Dethlefsen, Rolf; McNab, Ian; Dobbie, Clyde; Bernhardt, Tom; Puterbaugh, Robert; Levine, Frank; Coradeschi, Tom; Rinaldi, Vito

1993-01-01

Crowbar diodes are used for increasing the energy transfer from capacitive pulse forming networks. They also prevent voltage reversal on the energy storage capacitors. 52 mm diameter diodes with a 5 kV reverse blocking voltage, rated 40 kA were successfully used for the 32 MJ SSG rail gun. An uprated diode with increased current capability and a 15 kV reverse blocking voltage has been developed. Transient thermal analysis has predicted the current ratings for different pulse length. Analysis verification is obtained from destructive testing.

Calibration of ultra-high frequency (UHF) partial discharge sensors using FDTD method

Science.gov (United States)

Ishak, Asnor Mazuan; Ishak, Mohd Taufiq

2018-02-01

Ultra-high frequency (UHF) partial discharge sensors are widely used for conditioning monitoring and defect location in insulation system of high voltage equipment. Designing sensors for specific applications often requires an iterative process of manufacturing, testing and mechanical modifications. This paper demonstrates the use of finite-difference time-domain (FDTD) technique as a tool to predict the frequency response of UHF PD sensors. Using this approach, the design process can be simplified and parametric studies can be conducted in order to assess the influence of component dimensions and material properties on the sensor response. The modelling approach is validated using gigahertz transverse electromagnetic (GTEM) calibration system. The use of a transient excitation source is particularly suitable for modeling using FDTD, which is able to simulate the step response output voltage of the sensor from which the frequency response is obtained using the same post-processing applied to the physical measurement.

Memory properties and charge effect study in Si nanocrystals by scanning capacitance microscopy and spectroscopy

Directory of Open Access Journals (Sweden)

Bassani Franck

2011-01-01

Full Text Available Abstract In this letter, isolated Si nanocrystal has been formed by dewetting process with a thin silicon dioxide layer on top. Scanning capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in ambient temperature. The retention time of trapped charges injected by different direct current (DC bias were evaluated and compared. By ramp process, strong hysteresis window was observed. The DC spectra curve shift direction and distance was observed differently for quantitative measurements. Holes or electrons can be separately injected into these Si-ncs and the capacitance changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer scale. This study is very useful for nanocrystal charge trap memory application.

Characterization and spice simulation of a single-sided, p+ on n silicon microstrip detector before and after low-energy photon irradiation

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jiaguo; Klanner, Robert; Fretwurst, Eckhart [Institute for Experimental Physics, Detector Laboratory, University of Hamburg, Hamburg 22761 (Germany)

2010-07-01

As preparation for the development of silicon detectors for the harsh radiation environment at the European XFEL (up to 1 GGY 12 keV X-rays) p{sup +} on n silicon microstrip detectors were characterized as function of dose. The measurements, which include dark current, coupling capacitance, interstrip capacitance and interstrip resistance, are compared to a detailed SPICE model, so that the performance for particle detection can be estimated.

Undepleted silicon detectors

International Nuclear Information System (INIS)

Rancoita, P.G.; Seidman, A.

1985-01-01

Large-size silicon detectors employing relatively low resistivity material can be used in electromagnetic calorimetry. They can operate in strong magnetic fields, under geometric constraints and with microstrip detectors a high resolution can be achieved. Low noise large capacitance oriented electronics was developed to enable good signal-to-noise ratio for single relativistic particles traversing large area detectors. In undepleted silicon detectors, the charge migration from the field-free region has been investigated by comparing the expected peak position (from the depleted layer only) of the energy-loss of relativistic electrons with the measured one. Furthermore, the undepleted detectors have been employed in a prototype of Si/W electromagnetic colorimeter. The sensitive layer was found to be systematically larger than the depleted one

Experimental study of a variable-capacitance micromotor with electrostatic suspension

Science.gov (United States)

Han, F. T.; Wu, Q. P.; Wang, L.

2010-11-01

A variable-capacitance micromotor where the rotor is supported electrostatically in five degrees of freedom was designed, fabricated and tested in order to study the behavior of this electrostatic motor. The micromachined device is based on a glass/silicon/glass stack bonding structure, fabricated by bulk micromachining and initially operated in atmospheric environment. The analytical torque model is obtained by calculating the capacitances between different stator electrodes and the rotor. Capacitance values in the order of 10-13 pF and torque values in the order of 10-10 N m have been calculated from the motor geometry and attainable drive voltage. A dynamic model of the motor is proposed by further estimating the air-film damping effect in an effort to explain the experimental rotation measurements. Experimental results of starting voltage, continuous operation, switching response and electric bearing of the micromotor are presented and discussed. Preliminary measurements indicate that a rotor rotating speed of 73.3 r min-1 can be achieved at a drive voltage of 28.3 V, equivalent to a theoretical motive torque of 517 pN m. Starting voltage results obtained from experimental measurement are in agreement with the developed dynamic model.

New results on silicon microstrip detectors of CMS tracker

International Nuclear Information System (INIS)

Demaria, N.; Albergo, S.; Angarano, M.; Azzi, P.; Babucci, E.; Bacchetta, N.; Bader, A.; Bagliesi, G.; Basti, A.; Biggeri, U.; Bilei, G.M.; Bisello, D.; Boemi, D.; Bolla, G.; Bosi, F.; Borrello, L.; Bortoletto, D.; Bozzi, C.; Braibant, S.; Breuker, H.; Bruzzi, M.; Buffini, A.; Busoni, S.; Candelori, A.; Caner, A.; Castaldi, R.; Castro, A.; Catacchini, E.; Checcucci, B.; Ciampolini, P.; Civinini, C.; Creanza, D.; D'Alessandro, R.; Da Rold, M.; De Palma, M.; Dell'Orso, R.; Marina, R. Della; Dutta, S.; Eklund, C.; Elliott-Peisert, A.; Favro, G.; Feld, L.; Fiore, L.; Focardi, E.; French, M.; Freudenreich, K.; Fuertjes, A.; Giassi, A.; Giorgi, M.; Giraldo, A.; Glessing, B.; Gu, W.H.; Hall, G.; Hammerstrom, R.; Hebbeker, T.; Hrubec, J.; Huhtinen, M.; Kaminsky, A.; Karimaki, V.; Koenig, St.; Krammer, M.; Lariccia, P.; Lenzi, M.; Loreti, M.; Luebelsmeyer, K.; Lustermann, W.; Maettig, P.; Maggi, G.; Mannelli, M.; Mantovani, G.; Marchioro, A.; Mariotti, C.; Martignon, G.; Evoy, B. Mc; Meschini, M.; Messineo, A.; Migliore, E.; My, S.; Paccagnella, A.; Palla, F.; Pandoulas, D.; Papi, A.; Parrini, G.; Passeri, D.; Pieri, M.; Piperov, S.; Potenza, R.; Radicci, V.; Raffaelli, F.; Raymond, M.; Santocchia, A.; Schmitt, B.; Selvaggi, G.; Servoli, L.; Sguazzoni, G.; Siedling, R.; Silvestris, L.; Skog, K.; Starodumov, A.; Stavitski, I.; Stefanini, G.; Tempesta, P.; Tonelli, G.; Tricomi, A.; Tuuva, T.; Vannini, C.; Verdini, P.G.; Viertel, G.; Xie, Z.; Li Yahong; Watts, S.; Wittmer, B.

2000-01-01

Interstrip and backplane capacitances on silicon microstrip detectors with p + strip on n substrate of 320 μm thickness were measured for pitches between 60 and 240 μm and width over pitch ratios between 0.13 and 0.5. Parametrisations of capacitance w.r.t. pitch and width were compared with data. The detectors were measured before and after being irradiated to a fluence of 4x10 14 protons/cm 2 of 24 GeV/c momentum. The effect of the crystal orientation of the silicon has been found to have a relevant influence on the surface radiation damage, favouring the choice of a substrate. Working at high bias (up to 500 V in CMS) might be critical for the stability of detector, for a small width over pitch ratio. The influence found to enhance the stability

Capacitive Structures for Gas and Biological Sensing

KAUST Repository

Sapsanis, Christos

2015-04-01

The semiconductor industry was benefited by the advances in technology in the last decades. This fact has an impact on the sensors field, where the simple transducer was evolved into smart miniaturized multi-functional microsystems. However, commercially available gas and biological sensors are mostly bulky, expensive, and power-hungry, which act as obstacles to mass use. The aim of this work is gas and biological sensing using capacitive structures. Capacitive sensors were selected due to its design simplicity, low fabrication cost, and no DC power consumption. In the first part, the dominant structure among interdigitated electrodes (IDEs), fractal curves (Peano and Hilbert) and Archimedean spiral was investigated from capacitance density perspective. The investigation consists of geometrical formula calculations, COMSOL Multiphysics simulations and cleanroom fabrication of the capacitors on a silicon substrate. Moreover, low-cost fabrication on flexible plastic PET substrate was conducted outside cleanroom with rapid prototyping using a maskless laser etching. The second part contains the humidity, Volatile Organic compounds (VOCs) and Ammonia sensing of polymers, Polyimide and Nafion, and metal-organic framework (MOF), Cu(bdc)2.xH2O using IDEs and tested in an automated gas setup for experiment control and data extraction. The last part includes the biological sensing of C - reactive protein (CRP) quantification, which is considered as a biomarker of being prone to cardiac diseases and Bovine serum albumin (BSA) protein quantification, which is used as a reference for quantifying unknown proteins.

A p-nitroaniline redox-active solid-state electrolyte for battery-like electrochemical capacitive energy storage combined with an asymmetric supercapacitor based on metal oxide functionalized β-polytype porous silicon carbide electrodes.

Science.gov (United States)

Kim, Myeongjin; Yoo, Jeeyoung; Kim, Jooheon

2017-05-23

A unique redox active flexible solid-state asymmetric supercapacitor with ultra-high capacitance and energy density was fabricated using a composite comprising MgCo 2 O 4 nanoneedles and micro and mesoporous silicon carbide flakes (SiCF) (SiCF/MgCo 2 O 4 ) as the positive electrode material. Due to the synergistic effect of the two materials, this hybrid electrode has a high specific capacitance of 516.7 F g -1 at a scan rate of 5 mV s -1 in a 1 M KOH aqueous electrolyte. To obtain a reasonable matching of positive and negative electrode pairs, a composite of Fe 3 O 4 nanoparticles and SiCF (SiCF/Fe 3 O 4 ) was synthesized for use as a negative electrode material, which shows a high capacitance of 423.2 F g -1 at a scan rate of 5 mV s -1 . Therefore, by pairing the SiCF/MgCo 2 O 4 positive electrode and the SiCF/Fe 3 O 4 negative electrode with a redox active quasi-solid-state PVA-KOH-p-nitroaniline (PVA-KOH-PNA) gel electrolyte, a novel solid-state asymmetric supercapacitor device was assembled. Because of the synergistic effect between the highly porous SiCF and the vigorous redox-reaction of metal oxides, the hybrid nanostructure electrodes exhibited outstanding charge storage and transport. In addition, the redox active PVA-KOH-PNA electrolyte adds additional pseudocapacitance, which arises from the nitro-reduction and oxidation and reduction process of the reduction product of p-phenylenediamine, resulting in an enhancement of the capacitance (a specific capacitance of 161.77 F g -1 at a scan rate of 5 mV s -1 ) and energy density (maximum energy density of 72.79 Wh kg -1 at a power density of 727.96 W kg -1 ).

Textile-Based, Interdigital, Capacitive, Soft-Strain Sensor for Wearable Applications

Directory of Open Access Journals (Sweden)

Ozgur Atalay

2018-05-01

Full Text Available The electronic textile area has gained considerable attention due to its implementation of wearable devices, and soft sensors are the main components of these systems. In this paper, a new sensor design is presented to create stretchable, capacitance-based strain sensors for human motion tracking. This involves the use of stretchable, conductive-knit fabric within the silicone elastomer matrix, as interdigitated electrodes. While conductive fabric creates a secure conductive network for electrodes, a silicone-based matrix provides encapsulation and dimensional-stability to the structure. During the benchtop characterization, sensors show linear output, i.e., R2 = 0.997, with high response time, i.e., 50 ms, and high resolution, i.e., 1.36%. Finally, movement of the knee joint during the different scenarios was successfully recorded.

Capacitance-voltage investigation of silicon photodiodes damaged by MeV energy light ions

International Nuclear Information System (INIS)

Kalinka, G.; Simon, A.; Novak, M.; Kiss, A.Z.

2006-01-01

Complete text of publication follows. Nuclear radiation creates not only deep centers, but in addition influences shallow dopant concentration in semiconductors, as well. At a given temperature the maximum frequency a center can respond to depends on its energy level, therefore the capacitance-voltage (C-V) characteristics of radiation damaged semiconductor diodes should ideally be measured as function of frequency in order to obtain the physical and energy depth distribution of ionized centers [1,2]. In our experiments C-V plots of MeV energy ion irradiated photodiodes were taken at fixed 1 kHz frequency, which is low enough to be sensitive at room temperature to some of the deep levels expected. During, for example, an irradiation with 5.5 MeV α particles the capacitance of a p + nn + diode increased significantly at low voltages, but showed rather small changes at higher ones. The former turned out to be merely related to a decrease of the built in voltage, corresponding to a lifetime to relaxation type transition of the semiconductor [3]. Rescaling C-V data for this change, the remaining, actual capacitance changes could be interpreted as related to nuclear recoil caused damage located around the end of particle tracks. C-V technique has also been used for follow up investigation of spontaneous self annealing at room temperature of irradiated samples. This is shown here by plotting capacitance data normalized to their virgin values as function of depletion depth for irradiation with 430 keV protons, whose range is about 5 μm. The sensitivity of the method is illustrated for low fluence of 6.5 MeV oxygen, whose range is 5 μm, too, and where the normalization is now made to data taken one week after the irradiation. Acknowledgement This work was supported by the Hungarian Research and Technology Innovation Fund and the Croatian Ministry of Science, Education and Sports within the framework of the Hungarian-Croatian Intergovernmental Science and Technology Co

RFID antenna design for circular polarization in UHF band

Science.gov (United States)

Shahid, Hamza; Khan, Muhammad Talal Ali; Tayyab, Umais; Irshad, Usama Bin; Alkhazraji, Emad; Javaid, Muhammad Sharjeel

2017-05-01

A miniature half cross dipole antenna for defense and aerospace RFID applications in UHF band is presented. The dipole printed line arms are half crossed shape on top of dielectric substrate backed by reactive impedance surface. The antenna fed by a coaxial cable at the gap separating the dipole arms. Our design is intended to work at 2.42 GHz for RFID readers. The radiation pattern obtained has HPBW of 112, return loss of 22.24 dB and 90 MHz bandwidth.

Charge trapping and carrier transport mechanism in silicon-rich silicon oxynitride

International Nuclear Information System (INIS)

Yu Zhenrui; Aceves, Mariano; Carrillo, Jesus; Lopez-Estopier, Rosa

2006-01-01

The charge-trapping and carrier transport properties of silicon-rich silicon oxynitride (SRO:N) were studied. The SRO:N films were deposited by low pressure chemical vapor deposition. Infrared (IR) and transmission electron microscopic (TEM) measurements were performed to characterize their structural properties. Capacitance versus voltage and current versus voltage measurements (I-V) were used to study the charge-trapping and carrier transport mechanism. IR and TEM measurements revealed the existence of Si nanodots in SRO:N films. I-V measurements revealed that there are two conduction regimes divided by a threshold voltage V T . When the applied voltage is smaller than V T , the current is dominated by the charge transfer between the SRO:N and substrate; and in this regime only dynamic charging/discharging of the SRO:N layer is observed. When the voltage is larger than V T , the current increases rapidly and is dominated by the Poole-Frenkel mechanism; and in this regime, large permanent trapped charge density is obtained. Nitrogen incorporation significantly reduced the silicon nanodots or defects near the SRO:N/Si interface. However, a significant increase of the density of silicon nanodot in the bulk of the SRO:N layer is obtained

Label-free detection of sex determining region Y (SRY) via capacitive biosensor

KAUST Repository

Sivashankar, Shilpa

2016-10-20

In this work, we present for the first time, the use of a simple fractal capacitive biosensor for the quantification and detection of sex-determining region Y (SRY) genes. This section of genetic code, which is found on the Y chromosome, finds importance for study as it causes fetuses to develop characteristics of male sex-like gonads when a mutation occurs. It is also an important genetic code in men, and disorders involving the SRY gene can cause infertility and sexual malfunction that lead to a variety of gene mutational disorders. We have therefore designed silicon-based, label-free fractal capacitive biosensors to quantify various proteins and genes. We take advantage of a good dielectric material, Parylene C for enhancing the performance of the sensors. We have integrated these sensors with a simple microchannel for easy handling of fluids on the detection area. The read-out value of an Agilent LCR meter used to measure capacitance of the sensor at a frequency of 1 MHz determined gene specificity and gene quantification. These data revealed that the capacitance measurement of the capacitive biosensor for the SRY gene depended on both the target and the concentration of DNA. The experimental outcomes in the present study can be used to detect DNA and its variations in crucial fields that have a great impact on our daily lives, such as clinical and veterinary diagnostics, industrial and environmental testing and forensic sciences.

Copper thin film for RFID UHF antenna on flexible substrate

International Nuclear Information System (INIS)

Tran, Nhan Ai; Tran, Huy Nam; Dang, Mau Chien; Fribourg-Blanc, Eric

2010-01-01

A process flow using photolithography and sputtering was studied for copper antenna fabrication on thin poly(ethylene terephthalate) (PET) substrate. The lift-off route was chosen for its flexibility at laboratory scale. It was clarified that the cleaning of PET is an important step that necessitates mild oxygen plasma etching. Then copper is sputter deposited after photolithographic definition of the antenna. Care is necessary since PET, as a very flexible substrate, is temperature sensitive. The temperature increase generated by the impact of deposited copper should be maintained below the glass transition temperature of the polymer to avoid detrimental deformation. dc power of 40 to 50 W was found to be the maximum possible sputtering power for commercial PET. It was found that the resistivity of the thin film is below two times the bulk resistivity of copper for a deposition pressure below 4×10 −3  mbar and thickness above 450 nm. These results enable the reliable fabrication of copper RFID UHF antennae on a PET substrate for further testing of new tag designs. The present paper summarizes the effort to test new designs of antennae for RadioFrequency IDentification (RFID) Ultra High Frequency (UHF) tags, for use in various applications (e.g. object tracking and environment monitoring) in Vietnam

Assessment of immunomodulating action of combined therapy with UHF-hyperthermia in children with osteogenic sarcoma

International Nuclear Information System (INIS)

Neprina, G.S.; Panteleeva, E.S.; Vatin, O.E.; Bizer, V.A.; Bojko, I.N.

1989-01-01

The paper is concerned with immunological evaluation of different stages of combined therapy with local UHF-hyperthermia in children with osteogenic sarcoma. Combined therapy (polychemo- and raditherapy) was shown to cause a decrease in the number of immunocompetent cells, to enhance dysbalance of immunoregulatory T-lymphocytes, to weaken T-lymphocyte function on PHA; immunosuppressive action of combined therapy did not depend on a tumor site. The incorporation of UHF-hyperthermia in the therapeutic scheme weakened the manifestations of secondary immunodeficiency, got back to normal structure of T-lymphocyte population. A favorable immunomodulating effect of hyperthermia was more frequently observed in patients with crural bone tumors. The effect of hyperthermia was revealed after direct influence of thermotherapy but it was absent in continuation of combined treatment

Triangulating the Position of Antimony Donors Implanted in Silicon

Science.gov (United States)

Bureau-Oxton, Chloe; Nielsen, Erik; Luhman, Dwight; Ten Eyck, Gregory; Pluym, Tammy; Wendt, Joel; Pioro-Ladrière, Michel; Lilly, Michael; Carroll, Malcolm

2015-03-01

A potential candidate for a quantum bit is a single Sb atom implanted in silicon. A single-electron-transistor (SET) situated close to an Sb donor can be used to measure the occupancy and spin of the electron on the donor while the lithographically patterned poly-silicon gates defining the SET can be used to control donor occupancy. In our samples two clusters of Sb donors have been implanted adjacent to opposite sides of the SET through a self-aligned process. In this talk, we will present experimental results that allow us to determine the approximate position of different donors by determining their relative capacitance to pairs of the SET's poly-silicon gates. We will present the results of capacitive-based modeling calculations that allow us to further locate the position of the donors. This work was performed, in part, at the Center for Integrated Nanotechnologies, a U.S. DOE Office of Basic Energy Sciences user facility. Sandia National Laboratories is a multi-program laboratory operated by Sandia Corporation, a Lockheed-Martin Company, for the U. S. Department of Energy under Contract No. DE-AC04-94AL85000.

False capacitance of supercapacitors

OpenAIRE

Ragoisha, G. A.; Aniskevich, Y. M.

2016-01-01

Capacitance measurements from cyclic voltammetry, galvanostatic chronopotentiometry and calculation of capacitance from imaginary part of impedance are widely used in investigations of supercapacitors. The methods assume the supercapacitor is a capacitor, while real objects correspond to different equivalent electric circuits and show various contributions of non-capacitive currents to the current which is used for calculation of capacitance. Specific capacitances which are presented in F g-1...

Performance and Benchmarking of Multisurface UHF RFID Tags for Readability and Reliability

Directory of Open Access Journals (Sweden)

Joshua Bolton

2017-01-01

Full Text Available As the price of passive radio frequency identification (RFID tags continues to decrease, more and more companies are considering item-level tagging. Although the use of RFID is simple, its proper application should be studied to achieve maximum efficiency and utilization in the industry. This paper is intended to demonstrate the test results of various multisurface UHF tags from different manufacturers for their readability under varying conditions such as orientation of tags with respect to reader, distance of tag from the reader, and materials used for embedding tags. These conditions could affect the reliability of RFID systems used for varied applications. In this paper, we implement a Design for Six Sigma Research (DFSS-R methodology that allows for reliability testing of RFID systems. In this paper, we have showcased our results about the benchmarking of UHF RFID tags and have put forward an important observation about the blind spots observed at different distances and orientations along different surfaces, which is primarily due to the polarity of the antenna chosen.

Experimental study of a variable-capacitance micromotor with electrostatic suspension

International Nuclear Information System (INIS)

Han, F T; Wu, Q P; Wang, L

2010-01-01

A variable-capacitance micromotor where the rotor is supported electrostatically in five degrees of freedom was designed, fabricated and tested in order to study the behavior of this electrostatic motor. The micromachined device is based on a glass/silicon/glass stack bonding structure, fabricated by bulk micromachining and initially operated in atmospheric environment. The analytical torque model is obtained by calculating the capacitances between different stator electrodes and the rotor. Capacitance values in the order of 10 −13 pF and torque values in the order of 10 −10 N m have been calculated from the motor geometry and attainable drive voltage. A dynamic model of the motor is proposed by further estimating the air-film damping effect in an effort to explain the experimental rotation measurements. Experimental results of starting voltage, continuous operation, switching response and electric bearing of the micromotor are presented and discussed. Preliminary measurements indicate that a rotor rotating speed of 73.3 r min −1 can be achieved at a drive voltage of 28.3 V, equivalent to a theoretical motive torque of 517 pN m. Starting voltage results obtained from experimental measurement are in agreement with the developed dynamic model

Obtaining and electrical characterization of silicone/barium titanate composite for variable capacitor applications; Obtencao e caracterizacao eletrica de composito silicone/titanato de bario para aplicacoes em capacitor variavel

Energy Technology Data Exchange (ETDEWEB)

Vieira, D.A.; Souza, P.S.S.; Souza, C.P., E-mail: debora.vieira@cear.ufpb.br [Universidade Federal da Paraiba (UFPB), Joao Pessoa, PB (Brazil). Centro de Energias Alternativas e Renovaveis. Departamento de Engenharia Eletrica; Menezes, P.C.F. [Universidade Federal de Campina Grande (UFCG), Campina Grande, PB (Brazil). Departamento de Engenharia de Materiais

2014-07-01

Silicone/barium titanate composites are excellent candidates for applications in the production of electronics components. In this work, silicone/barium titanate composite was obtained for the production of capacitors with variable dielectric distance. The mixture of composite (20% of barium titanate) was performed in a mixer with stem type propellers, at room temperature for 20 minutes. The cure was held in vacuum kiln. After obtaining the composite, was mounted a parallel plate capacitor, using composite as dielectric. The composite obtained was subjected to x-ray diffraction, scanning electron microscopy and capacitive electrical test. The DRX confirms the presence of ceramic charge in composite with the presence of broad peaks of barium titanate and micrographs show the barium titanate particles dispersed in polymer matrix. The capacitance of the sample was approximately 28,7pF. (author)

Development of micro capacitive accelerometer for subsurface microseismic measurement. Second Report; Micromachining ni yoru chika danseiha kenshutsu no tame no silicone yoryogata kasokudo sensor no seisaku. 2

Energy Technology Data Exchange (ETDEWEB)

Nishizawa, M; Lim, G; Niitsuma, H; Esashi, M [Tohoku University, Sendai (Japan)

1997-10-22

Micromachining-aided manufacture is under way of a silicon capacitive accelerator sensor, high in sensitivity and broad in bandwidth, for detecting subsurface microseismic waves. The sensor detects acceleration by use of changes in capacities of the top and bottom capacitors generated when a spring-supported weight experiences displacement upon application of acceleration to the said weight. A diode bridge circuit is employed as the circuit for detecting acceleration. As for sensitivity of the sensor, when the virtual noise inputted into the electronic circuit is presumed at 1{mu}V and the circuit driving voltage at 5V, the sensor minimum detectability will be 2.5mgal in the presence of a 3{mu}m gap between the weight and an electrode plate. The natural vibration frequency is set at 1kHz. Such specifications may be realized using the current micromachining technology, and possibilities are that the bandwidth will be further expanded when the sensor is used in a servo-type configuration. The effort is still at the stage of acceleration sensor manufacturing, with a stopper just formed for the silicon weight. 9 refs., 6 figs., 1 tab.

A new interface weak-capacitance detection ASIC of capacitive liquid level sensor in the rocket

Science.gov (United States)

Yin, Liang; Qin, Yao; Liu, Xiao-Wei

2017-11-01

A new capacitive liquid level sensing interface weak-capacitance detection ASIC has been designed. This ASIC realized the detection of the output capacitance of the capacitive liquid level sensor, which converts the output capacitance of the capacitive liquid level sensor to voltage. The chip is fabricated in a standard 0.5μm CMOS process. The test results show that the linearity of capacitance detection of the ASIC is 0.05%, output noise is 3.7aF/Hz (when the capacitance which will be detected is 40 pF), the stability of capacitance detection is 7.4 × 10-5pF (1σ, 1h), the output zero position temperature coefficient is 4.5 uV/∘C. The test results prove that this interface ASIC can meet the requirement of high accuracy capacitance detection. Therefore, this interface ASIC can be applied in capacitive liquid level sensing and capacitive humidity sensing field.

Development of 3D carbon nanotube interdigitated finger electrodes on polymer substrate for flexible capacitive sensor application

International Nuclear Information System (INIS)

Hu, Chih-Fan; Wang, Jhih-Yu; Fang, Weileun; Liu, Yu-Chia; Tsai, Ming-Han

2013-01-01

This study reports a novel approach to the implementation of 3D carbon nanotube (CNT) interdigitated finger electrodes on flexible polymer, and the detection of strain, bending curvature, tactile force and proximity distance are demonstrated. The merits of the presented CNT-based flexible sensor are as follows: (1) the silicon substrate is patterned to enable the formation of 3D vertically aligned CNTs on the substrate surface; (2) polymer molding on the silicon substrate with 3D CNTs is further employed to transfer the 3D CNTs to the flexible polymer substrate; (3) the CNT–polymer composite (∼70 μm in height) is employed to form interdigitated finger electrodes to increase the sensing area and initial capacitance; (4) other structures such as electrical routings, resistors and mechanical supporters are also available using the CNT–polymer composite. The preliminary fabrication results demonstrate a flexible capacitive sensor with 50 μm high CNT interdigitated electrodes on a poly-dimethylsiloxane substrate. The tests show that the typical capacitance change is several dozens of fF and the gauge factor is in the range of 3.44–4.88 for strain and bending curvature measurement; the sensitivity of the tactile sensor is 1.11% N −1 ; a proximity distance near 2 mm away from the sensor can be detected. (paper)

Energy-Efficient Capacitance-to-Digital Converters for Smart Sensor Applications

KAUST Repository

Alhoshany, Abdulaziz

2017-12-01

One of the key requirements in the design of wireless sensor nodes and miniature biomedical devices is energy efficiency. For a sensor node, which is a sensor and readout circuit, to survive on limited energy sources such as a battery or harvested energy, its energy consumption should be minimized. Capacitive sensors are candidates for use in energy-constrained applications, as they do not consume static power and can be used in a wide range of applications to measure different physical, chemical or biological quantities. However, the energy consumption is dominated by the capacitive interface circuit, i.e. the capacitance-to-digital converter (CDC). Several energy-efficient CDC architectures are introduced in this dissertation to meet the demand for high resolution and energy efficiency in smart capacitive sensors. First, we propose an energy-efficient CDC based on a differential successive-approximation data converter. The proposed differential CDC employs an energy-efficient operational transconductance amplifier (OTA) based on an inverter. A wide capacitance range with fine absolute resolution is implemented in the proposed coarse-fine DAC architecture which saves 89% of silicon area. The proposed CDC achieves an energy efficiency figure-of-merit () of 45.8fJ/step, which is the best reported energy efficiency to date. Second, we propose an energy efficient CDC for high-precision capacitive resolution by using oversampling and noise shaping. The proposed CDC achieves 150 aF absolute resolution and an energy efficiency of 187fJ/conversion-step which outperforms state of the art high-precision differential CDCs. In the third and last part, we propose an in-vitro cancer diagnostic biosensor-CMOS platform for low-power, rapid detection, and low cost. The introduced platform is the first to demonstrate the ability to screen and quantify the spermidine/spermine N1 acetyltransferase (SSAT) enzyme which reveals the presence of early-stage cancer, on the surface of a

Comparison of UHF measurements with the propagation model of Recommendation ITU-R P.1546

NARCIS (Netherlands)

Witvliet, B.A.; Wijninga, P.W.; van Maanen, E.; Smith, B.

2010-01-01

This report describes a radio propagation measurement campaign that has been performed along paths between the Netherlands and the United Kingdom. The campaign focused on UHF propagation on mixed land/sea paths. Special attention was given to calibration accuracy and validation of the measurement

Suppression of irradiation effects in gold-doped silicon detectors

International Nuclear Information System (INIS)

McPherson, M.; Sloan, T.; Jones, B.K.

1997-01-01

Two sets of silicon detectors were irradiated with 1 MeV neutrons to different fluences and then characterized. The first batch were ordinary p-i-n photodiodes fabricated from high-resistivity (400 Ω cm) silicon, while the second batch were gold-doped powder diodes fabricated from silicon material initially of low resistivity (20 Ω cm). The increase in reverse leakage current after irradiation was found to be more in the former case than in the latter. The fluence dependence of the capacitance was much more pronounced in the p-i-n diodes than in the gold-doped diodes. Furthermore, photo current generation by optical means was less in the gold doped devices. All these results suggest that gold doping in silicon somewhat suppresses the effects of neutron irradiation. (author)

GPM GROUND VALIDATION NOAA UHF 449 PROFILER RAW DATA SPC FORMAT MC3E V1

Data.gov (United States)

National Aeronautics and Space Administration — The NOAA UHF 449 Profiler Raw SPC foramt data was collected during the NASA supported Midlatitude Continental Convective Clouds Experiment (MC3E). The Ultra High...

GPM GROUND VALIDATION NOAA UHF 449 PROFILER RAW DATA SPC FORMAT MC3E V1

Data.gov (United States)

National Aeronautics and Space Administration — The GPM Ground Validation NOAA UHF 449 Profiler Raw Data SPC Format MC3E dataset was collected during the NASA supported Midlatitude Continental Convective Clouds...

Investigating Feasibility of Multiple UHF Passive RFID Transmitters Using Backscatter Modulation Scheme in BCI Applications

DEFF Research Database (Denmark)

Al Ajrawi, Shams; Sarkar, Mahasweta; Mihovska, Albena

Building a wireless body area network (WBAN) application including implantable transceivers placed inside the human brain to collect the data from the electrodes and transmit them wirelessly to a controller placed outside the brain on the scalp faced major challenges. The transmission...... using passive RFID as the implantable transmitters and letting them operate in the UHF range. Backscatter modulation has been used as a power transfer mechanism. Investigation on the feasibility and applicability of implantable UHF Passive RFID transmitters inside the brain is done for capturing multi......-channel ECoG signals when traversing through a phantom brain model as a transmission medium for the experiments at a high data transfer rate. Detailed analysis has been done on parameters such as Received Signal Strength Indication (RSSI), signal to noise ratio (SNR), Maximum number of electrodes, Path Loss...

Graphene synthesized on porous silicon for active electrode material of supercapacitors

Science.gov (United States)

Su, B. B.; Chen, X. Y.; Halvorsen, E.

2016-11-01

We present graphene synthesized by chemical vapour deposition under atmospheric pressure on both porous nanostructures and flat wafers as electrode scaffolds for supercapacitors. A 3nm thin gold layer was deposited on samples of both porous and flat silicon for exploring the catalytic influence during graphene synthesis. Micro-four-point probe resistivity measurements revealed that the resistivity of porous silicon samples was nearly 53 times smaller than of the flat silicon ones when all the samples were covered by a thin gold layer after the graphene growth. From cyclic voltammetry, the average specific capacitance of porous silicon coated with gold was estimated to 267 μF/cm2 while that without catalyst layer was 145μF/cm2. We demonstrated that porous silicon based on nanorods can play an important role in graphene synthesis and enable silicon as promising electrodes for supercapacitors.

VHF/UHF imagery and RCS measurements of ground targets in forested terrain

Science.gov (United States)

Gatesman, Andrew J.; Beaudoin, Christopher J.; Giles, Robert H.; Waldman, Jerry; Nixon, William E.

2002-08-01

The monostatic VV and HH-polarized radar signatures of several targets and trees have been measured at foliage penetration frequencies (VHF/UHF) by using 1/35th scale models and an indoor radar range operating at X-band. An array of high-fidelity scale model ground vehicles and test objects as well as scaled ground terrain and trees have been fabricated for the study. Radar measurement accuracy has been confirmed by comparing the signature of a test object with a method of moments radar cross section prediction code. In addition to acquiring signatures of targets located on a smooth, dielectric ground plane, data have also been acquired with targets located in simulated wooded terrain that included scaled tree trunks and tree branches. In order to assure the correct backscattering behavior, all dielectric properties of live tree wood and moist soil were scaled properly to match the complex dielectric constant of the full-scale materials. The impact of the surrounding tree clutter on the VHF/UHF radar signatures of ground vehicles was accessed. Data were processed into high-resolution, polar-formatted ISAR imagery and signature comparisons are made between targets in open-field and forested scenarios.

Un sistema RFID in banda UHF per l'autoprestito in Biblioteca

OpenAIRE

Ricci, Franco; Crisanti, Andrea

2009-01-01

Department of Physics and CASPUR have been starting, in the past 2 years, a collaborationin order to develop a new RFID (Radio Frequency IDentification) system for automaticlibrary loan procedures. These systems (generally known as self-checkequipments) uses radio signals in the UHF frequency range to interact with antennas(passive tags) used to identify books. Users identification is made through special cardswith an embedded tag. The entire loan process is completely managed by users throug...

Gate tunneling current and quantum capacitance in metal-oxide-semiconductor devices with graphene gate electrodes

Science.gov (United States)

An, Yanbin; Shekhawat, Aniruddh; Behnam, Ashkan; Pop, Eric; Ural, Ant

2016-11-01

Metal-oxide-semiconductor (MOS) devices with graphene as the metal gate electrode, silicon dioxide with thicknesses ranging from 5 to 20 nm as the dielectric, and p-type silicon as the semiconductor are fabricated and characterized. It is found that Fowler-Nordheim (F-N) tunneling dominates the gate tunneling current in these devices for oxide thicknesses of 10 nm and larger, whereas for devices with 5 nm oxide, direct tunneling starts to play a role in determining the total gate current. Furthermore, the temperature dependences of the F-N tunneling current for the 10 nm devices are characterized in the temperature range 77-300 K. The F-N coefficients and the effective tunneling barrier height are extracted as a function of temperature. It is found that the effective barrier height decreases with increasing temperature, which is in agreement with the results previously reported for conventional MOS devices with polysilicon or metal gate electrodes. In addition, high frequency capacitance-voltage measurements of these MOS devices are performed, which depict a local capacitance minimum under accumulation for thin oxides. By analyzing the data using numerical calculations based on the modified density of states of graphene in the presence of charged impurities, it is shown that this local minimum is due to the contribution of the quantum capacitance of graphene. Finally, the workfunction of the graphene gate electrode is extracted by determining the flat-band voltage as a function of oxide thickness. These results show that graphene is a promising candidate as the gate electrode in metal-oxide-semiconductor devices.

Resonance of conductivity in UHF-range to the action of alternating current in La0.7Pb0.3MnO3 crystals

International Nuclear Information System (INIS)

Volkov, N.V.; Petrakovskij, G.A.; Sablina, K.A.

1999-01-01

The experimental results of the study on the effect of the low frequency transport current on the conductivity in UHF-range of the La 0.7 Pb 0.3 MnO 3 monocrystals are presented. In absence of the external magnetic field the UHF-conductivity response signal on the current impact has the form of the relaxation process. The peak of the amplitude resonance growth is observed in the external magnetic field in the response spectrum. The resonance response is of nonlinear character. The temperature and field dependences of the UHF-response basic parameters are in direct correlation with the magnetoresistance behaviour. The results obtained are analyzed within the frames of the oscillatory approximation. The mechanism of the phases electron separation is proposed as the possible mechanism of the current impact [ru

Transient performance estimation of charge plasma based negative capacitance junctionless tunnel FET

International Nuclear Information System (INIS)

Singh, Sangeeta; Kondekar, P. N.; Pal, Pawan

2016-01-01

We investigate the transient behavior of an n-type double gate negative capacitance junctionless tunnel field effect transistor (NC-JLTFET). The structure is realized by using the work-function engineering of metal electrodes over a heavily doped n + silicon channel and a ferroelectric gate stack to get negative capacitance behavior. The positive feedback in the electric dipoles of ferroelectric materials results in applied gate bias boosting. Various device transient parameters viz. transconductance, output resistance, output conductance, intrinsic gain, intrinsic gate delay, transconductance generation factor and unity gain frequency are analyzed using ac analysis of the device. To study the impact of the work-function variation of control and source gate on device performance, sensitivity analysis of the device has been carried out by varying these parameters. Simulation study reveals that it preserves inherent advantages of charge-plasma junctionless structure and exhibits improved transient behavior as well. (paper)

Titanium nitride films for micro-supercapacitors: Effect of surface chemistry and film morphology on the capacitance

Science.gov (United States)

Achour, Amine; Porto, Raul Lucio; Soussou, Mohamed-Akram; Islam, Mohammad; Boujtita, Mohammed; Aissa, Kaltouma Ait; Le Brizoual, Laurent; Djouadi, Abdou; Brousse, Thierry

2015-12-01

Electrochemical capacitors (EC) in the form of packed films can be integrated in various electronic devices as power source. A fabrication process of EC electrodes, which is compatible with micro-fabrication, should be addressed for practical applications. Here, we show that titanium nitride films with controlled porosity can be deposited on flat silicon substrates by reactive DC-sputtering for use as high performance micro-supercapacitor electrodes. A superior volumetric capacitance as high as 146.4 F cm-3, with an outstanding cycling stability over 20,000 cycles, was measured in mild neutral electrolyte of potassium sulfate. The specific capacitance of the films as well as their capacitance retentions were found to depend on thickness, porosity and surface chemistry of electrodes. The one step process used to fabricate these TiN electrodes and the wide use of this material in the field of semiconductor technology make it promising for miniaturized energy storage systems.

Characterisation of Silicon Pad Diodes

CERN Document Server

Hodson, Thomas Connor

2017-01-01

Silicon pad sensors are used in high luminosity particle detectors because of their excellent timing resolution, radiation tolerance and possible high granularity. The effect of different design decisions on detector performance can be investigated nondestructively through electronic characterisation of the sensor diodes. Methods for making accurate measurements of leakage current and cell capacitance are described using both a standard approach with tungsten needles and an automated approach with a custom multiplexer and probing setup.

Ion-step method for surface potential sensing of silicon nanowires

NARCIS (Netherlands)

Chen, S.; van Nieuwkasteele, Jan William; van den Berg, Albert; Eijkel, Jan C.T.

2016-01-01

This paper presents a novel stimulus-response method for surface potential sensing of silicon nanowire (Si NW) field-effect transistors. When an "ion-step" from low to high ionic strength is given as a stimulus to the gate oxide surface, an increase of double layer capacitance is therefore expected.

UHF RFID tag implementation on cork substrate for wine bottle monitoring

OpenAIRE

Rima Martí, Sergi; Georgiadis, Apostolos

2013-01-01

Wine industry is starting to deploy RFID technology for production control, logistics or innovative marketing. However, identifying wine bottles is difficult due to the unfavorable material content for the operation of the antennas. The thesis consists on the implementation of a UHF RFID tag placed on cork substrate in order to provide a feasible way of identifying wine packaged bottle. The proposed RFID tag consists on a meandered line dipole antenna, designed to be conformed so that it can ...

Graphene synthesized on porous silicon for active electrode material of supercapacitors

International Nuclear Information System (INIS)

Su, B B; Chen, X Y; Halvorsen, E

2016-01-01

We present graphene synthesized by chemical vapour deposition under atmospheric pressure on both porous nanostructures and flat wafers as electrode scaffolds for supercapacitors. A 3nm thin gold layer was deposited on samples of both porous and flat silicon for exploring the catalytic influence during graphene synthesis. Micro-four-point probe resistivity measurements revealed that the resistivity of porous silicon samples was nearly 53 times smaller than of the flat silicon ones when all the samples were covered by a thin gold layer after the graphene growth. From cyclic voltammetry, the average specific capacitance of porous silicon coated with gold was estimated to 267 μF/cm 2 while that without catalyst layer was 145μF/cm 2 . We demonstrated that porous silicon based on nanorods can play an important role in graphene synthesis and enable silicon as promising electrodes for supercapacitors. (paper)

Disordered redox metabolism of brain cells in rats exposed to low doses of ionizing radiation or UHF electromagnetic radiation.

Science.gov (United States)

Burlaka, A P; Druzhyna, M O; Vovk, A V; Lukin, S М

2016-12-01

To investigate the changes of redox-state of mammalian brain cells as the critical factor of initiation and formation of radiation damage of biological structures in setting of continuous exposure to low doses of ionizing radiation or fractionated ultra high frequency electromagnetic radiation (UHF EMR) at non-thermal levels. The influence of low-intensity ionizing radiation was studied on outbred female rats kept for 1.5 years in the Chernobyl accident zone. The effects of total EMR in the UHF band of non-thermal spectrum were investigated on Wistar rats. The rate of formation of superoxide radicals and the rate of NO synthesis in mitochondria were determined by the EPR. After exposure to ionizing or UHF radiation, the levels of ubisemiquinone in brain tissue of rats decreased by 3 and 1.8 times, respectively. The content of NO-FeS-protein complexes in both groups increased significantly (р < 0.05). In the conditions of ionizing or EMR the rates of superoxide radical generation in electron-transport chain of brain cell mitochondria increased by 1.5- and 2-fold, respectively (р < 0.05). In brain tissue of rats kept in the Chernobyl zone, significant increase of NO content was registered; similar effect was observed in rats treated with UHFR (р < 0.05). The detected changes in the electron transport chain of mitochondria of brain cells upon low-intensity irradiation or UHF EMR cause the metabolic reprogramming of cell mitochondria that increases the rate of superoxide radical generation and nitric oxide, which may initiate the development of neurodegenerative diseases and cancer. This article is part of a Special Issue entitled "The Chornobyl Nuclear Accident: Thirty Years After".

Dielectric properties of DNA oligonucleotides on the surface of silicon nanostructures

Energy Technology Data Exchange (ETDEWEB)

Bagraev, N. T., E-mail: bagraev@mail.ioffe.ru [St. Petersburg Polytechnic University (Russian Federation); Chernev, A. L. [Russian Academy of Sciences, St. Petersburg Academic University—Nanotechnology Research and Education Center (Russian Federation); Klyachkin, L. E. [St. Petersburg Polytechnic University (Russian Federation); Malyarenko, A. M. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Emel’yanov, A. K.; Dubina, M. V. [Russian Academy of Sciences, St. Petersburg Academic University—Nanotechnology Research and Education Center (Russian Federation)

2016-10-15

Planar silicon nanostructures that are formed as a very narrow silicon quantum well confined by δ barriers heavily doped with boron are used to study the dielectric properties of DNA oligonucleotides deposited onto the surface of the nanostructures. The capacitance characteristics of the silicon nanostructures with oligonucleotides deposited onto their surface are determined by recording the local tunneling current–voltage characteristics by means of scanning tunneling microscopy. The results show the possibility of identifying the local dielectric properties of DNA oligonucleotide segments consisting of repeating G–C pairs. These properties apparently give grounds to correlate the segments with polymer molecules exhibiting the properties of multiferroics.

FSL based estimation of white space availability in UHF TV bands in Bergvliet, South Africa

CSIR Research Space (South Africa)

Lysko, AA

2012-09-01

Full Text Available in the UHF TV frequency bands. The free space loss (FSL) formula, together with a line of sight condition, are applied to the information about the location and power of TV transmitters around this area. The predictions show 61% correlation between...

A new tevchnique for production of amorphous silicon solar cells

International Nuclear Information System (INIS)

Andrade, A.M. de; Pereyra, I.; Sanematsu, M.S.; Corgnier, S.L.L.; Fonseca, F.J.

1984-01-01

It is presented a new technique for the production of amorphous silicon solar cells based on the development of thin films of a-Si in a reactor in which the decomposition of the sylane, induced by capacitively coupled RF, and the film deposition occur in separate chambers. (M.W.O.) [pt

VHF/UHF radar observations of tropical mesoscale convective systems over southern India

Directory of Open Access Journals (Sweden)

K. Kishore Kumar

2005-07-01

Full Text Available Several campaigns have been carried out to study the convective systems over Gadanki (13.5° N, 79.2° E, a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaigns. The observed systems are classified into single- and multi-cell systems. It has been observed that most of the convective systems at this latitude are multi-cellular in nature. Simultaneous VHF and UHF radar observations are used to classify the observed precipitating systems as convective, intermediary and stratiform regions. Composite height profiles of vertical velocities in these regions were obtained and the same were compared with the profiles obtained at other geographical locations. These composite profiles of vertical velocity in the convective regions have shown their peaks in the mid troposphere, indicating that the maximum latent heat is being released at those heights. These profiles are very important for numerical simulations of the convective systems, which vary significantly from one geographical location to the other.

Keywords. Meteorology and atmospheric dynamics (Mesoscale meteorology; Convective processes – Radio science (Remote sensing

VHF/UHF radar observations of tropical mesoscale convective systems over southern India

Directory of Open Access Journals (Sweden)

K. Kishore Kumar

2005-07-01

Full Text Available Several campaigns have been carried out to study the convective systems over Gadanki (13.5° N, 79.2° E, a tropical station in India, using VHF and UHF radars. The height-time sections of several convective systems are investigated in detail to study reflectivity, turbulence and vertical velocity structure. Structure and dynamics of the convective systems are the main objectives of these campaigns. The observed systems are classified into single- and multi-cell systems. It has been observed that most of the convective systems at this latitude are multi-cellular in nature. Simultaneous VHF and UHF radar observations are used to classify the observed precipitating systems as convective, intermediary and stratiform regions. Composite height profiles of vertical velocities in these regions were obtained and the same were compared with the profiles obtained at other geographical locations. These composite profiles of vertical velocity in the convective regions have shown their peaks in the mid troposphere, indicating that the maximum latent heat is being released at those heights. These profiles are very important for numerical simulations of the convective systems, which vary significantly from one geographical location to the other. Keywords. Meteorology and atmospheric dynamics (Mesoscale meteorology; Convective processes – Radio science (Remote sensing

Partial Discharge Spectral Characterization in HF, VHF and UHF Bands Using Particle Swarm Optimization.

Science.gov (United States)

Robles, Guillermo; Fresno, José Manuel; Martínez-Tarifa, Juan Manuel; Ardila-Rey, Jorge Alfredo; Parrado-Hernández, Emilio

2018-03-01

The measurement of partial discharge (PD) signals in the radio frequency (RF) range has gained popularity among utilities and specialized monitoring companies in recent years. Unfortunately, in most of the occasions the data are hidden by noise and coupled interferences that hinder their interpretation and renders them useless especially in acquisition systems in the ultra high frequency (UHF) band where the signals of interest are weak. This paper is focused on a method that uses a selective spectral signal characterization to feature each signal, type of partial discharge or interferences/noise, with the power contained in the most representative frequency bands. The technique can be considered as a dimensionality reduction problem where all the energy information contained in the frequency components is condensed in a reduced number of UHF or high frequency (HF) and very high frequency (VHF) bands. In general, dimensionality reduction methods make the interpretation of results a difficult task because the inherent physical nature of the signal is lost in the process. The proposed selective spectral characterization is a preprocessing tool that facilitates further main processing. The starting point is a clustering of signals that could form the core of a PD monitoring system. Therefore, the dimensionality reduction technique should discover the best frequency bands to enhance the affinity between signals in the same cluster and the differences between signals in different clusters. This is done maximizing the minimum Mahalanobis distance between clusters using particle swarm optimization (PSO). The tool is tested with three sets of experimental signals to demonstrate its capabilities in separating noise and PDs with low signal-to-noise ratio and separating different types of partial discharges measured in the UHF and HF/VHF bands.

Doping profile measurement on textured silicon surface

Science.gov (United States)

Essa, Zahi; Taleb, Nadjib; Sermage, Bernard; Broussillou, Cédric; Bazer-Bachi, Barbara; Quillec, Maurice

2018-04-01

In crystalline silicon solar cells, the front surface is textured in order to lower the reflection of the incident light and increase the efficiency of the cell. This texturing whose dimensions are a few micrometers wide and high, often makes it difficult to determine the doping profile measurement. We have measured by secondary ion mass spectrometry (SIMS) and electrochemical capacitance voltage profiling the doping profile of implanted phosphorus in alkaline textured and in polished monocrystalline silicon wafers. The paper shows that SIMS gives accurate results provided the primary ion impact angle is small enough. Moreover, the comparison between these two techniques gives an estimation of the concentration of electrically inactive phosphorus atoms.

Estimating the Permittivity of Rogers 4003C Substrate at Low Frequencies for Application in a Superdirective First-Order Probe for SNF Measurements

DEFF Research Database (Denmark)

Kim, Oleksiy S.

2016-01-01

The bulk permittivity of Rogers 4003C substrate is estimated in the lower UHF frequency band by comparing the simulated and measured return loss for a bandpass filter based on a coplanar waveguide and a capacitively loaded loop. The obtained value, which deviates from that specified by Rogers at ...... GHz, is subsequently utilized for accurate design of a new light-weight superdirective first-order probe for spherical near-field (SNF) antenna measurements at low frequencies.......The bulk permittivity of Rogers 4003C substrate is estimated in the lower UHF frequency band by comparing the simulated and measured return loss for a bandpass filter based on a coplanar waveguide and a capacitively loaded loop. The obtained value, which deviates from that specified by Rogers at 10...

Meteor head echo altitude distributions and the height cutoff effect studied with the EISCAT HPLA UHF and VHF radars

Directory of Open Access Journals (Sweden)

A. Westman

2004-04-01

Full Text Available Meteor head echo altitude distributions have been derived from data collected with the EISCAT VHF (224MHz and UHF (930MHz high-power, large-aperture (HPLA radars. At the high-altitude end, the distributions cut off abruptly in a manner reminiscent of the trail echo height ceiling effect observed with classical meteor radars. The target dimensions are shown to be much smaller than both the VHF and the UHF probing wavelengths, but the cutoff heights for the two systems are still clearly different, the VHF cutoff being located several km above the UHF one. A single-collision meteor-atmosphere interaction model is used to demonstrate that meteors in the (1.3–7.2µg mass range will ionise such that critical electron density at 224MHz is first reached at or around the VHF cutoff altitude and critical density at 930MHz will be reached at the UHF cutoff altitude. The observed seasonal variation in the cutoff altitudes is shown to be a function of the seasonal variation of atmospheric density with altitude. Assuming that the electron density required for detection is in the order of the critical density, the abrupt altitude cutoffs can be explained as a consequence of the micrometeoroid joint size-speed distribution dropping off so fast at the large-mass, high-velocity end that above a certain altitude the number of detectable events becomes vanishingly small. Conversely, meteors at the low-mass end of the distribution will be gradually retarded such that the ionisation they generate never reaches critical density. These particles will remain unobservable.Key words. Radio science (instruments and techniques – Interplatery physics (interplanetary dust – General or miscellaneous (new fields

Capacitive chemical sensor

Science.gov (United States)

Manginell, Ronald P; Moorman, Matthew W; Wheeler, David R

2014-05-27

A microfabricated capacitive chemical sensor can be used as an autonomous chemical sensor or as an analyte-sensitive chemical preconcentrator in a larger microanalytical system. The capacitive chemical sensor detects changes in sensing film dielectric properties, such as the dielectric constant, conductivity, or dimensionality. These changes result from the interaction of a target analyte with the sensing film. This capability provides a low-power, self-heating chemical sensor suitable for remote and unattended sensing applications. The capacitive chemical sensor also enables a smart, analyte-sensitive chemical preconcentrator. After sorption of the sample by the sensing film, the film can be rapidly heated to release the sample for further analysis. Therefore, the capacitive chemical sensor can optimize the sample collection time prior to release to enable the rapid and accurate analysis of analytes by a microanalytical system.

Design and Tests of the Silicon Sensors for the ZEUS Micro Vertex Detector

OpenAIRE

Dannheim, D.; Koetz, U.; Coldewey, C.; Fretwurst, E.; Garfagnini, A.; Klanner, R.; Martens, J.; Koffeman, E.; Tiecke, H.; Carlin, R.

2002-01-01

To fully exploit the HERA-II upgrade,the ZEUS experiment has installed a Micro Vertex Detector (MVD) using n-type, single-sided, silicon micro-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 micrometers, with five intermediate strips (20 micrometer strip pitch). The designs of the silicon sensors and of the test structures used to verify the technological parameters, are presented. Results on the electrical measurements are discussed. A total of 1123 sen...

Considerations on the design of front-end electronics for silicon calorimetry for the SSC

International Nuclear Information System (INIS)

Wintenberg, A.L.; Bauer, M.L.; Britton, C.L.; Kennedy, E.J.; Todd, R.A.; Berridge, S.C.; Bugg, W.M.

1990-01-01

Some considerations are described for the design of a silicon-based sampling calorimetry detector for the Superconducting Super Collider (SSC). The use of silicon as the detection medium allows fast, accurate, and fine-grained energy measurements - but for optimal performance, the front-end electronics must be matched to the detector characteristics and have the speed required by the high SSC interaction rates. The relation between the signal-to-noise rtio of the calorimeter electronics and the charge collection time, the preamplifier power dissipation, detector capacitance and leakage, charge gain, and signal shaping and sampling was studied. The electrostatic transformer connection was analyzed and found to be unusable for a tightly arranged calorimeter because of stray capacitance effects. The method of deconvolutional sampling was developed as a means for pileup correction following synchronous sampling and analog storage

Characterization procedures for double-sided silicon microstrip detectors

Energy Technology Data Exchange (ETDEWEB)

Bruner, N.L. [New Mexico Univ., Albuquerque, NM (United States). New Mexico Center for Particle Phys.; Frautschi, M.A. [New Mexico Univ., Albuquerque, NM (United States). New Mexico Center for Particle Phys.; Hoeferkamp, M.R. [New Mexico Univ., Albuquerque, NM (United States). New Mexico Center for Particle Phys.; Seidel, S.C. [New Mexico Univ., Albuquerque, NM (United States). New Mexico Center for Particle Phys.

1995-08-15

Since double-sided silicon microstrip detectors are still evolving technologically and are not yet commercially available, they require extensive electrical evaluation by the user to ensure they were manufactured to specifications. In addition, measurements must be performed to determine detector operating conditions. Procedures for measuring the following quantities are described: - Leakage current, - Depletion voltage, - Bias resistance, - Interstrip resistance, - Coupling capacitance, - Coupling capacitor breakdown voltage. (orig.).

Characterization procedures for double-sided silicon microstrip detectors

International Nuclear Information System (INIS)

Bruner, N.L.; Frautschi, M.A.; Hoeferkamp, M.R.; Seidel, S.C.

1995-01-01

Since double-sided silicon microstrip detectors are still evolving technologically and are not yet commercially available, they require extensive electrical evaluation by the user to ensure they were manufactured to specifications. In addition, measurements must be performed to determine detector operating conditions. Procedures for measuring the following quantities are described: - Leakage current, - Depletion voltage, - Bias resistance, - Interstrip resistance, - Coupling capacitance, - Coupling capacitor breakdown voltage. (orig.)

A study of timing properties of Silicon Photomultipliers

Science.gov (United States)

Avella, Paola; De Santo, Antonella; Lohstroh, Annika; Sajjad, Muhammad T.; Sellin, Paul J.

2012-12-01

Silicon Photomultipliers (SiPMs) are solid-state pixelated photodetectors. Lately these sensors have been investigated for Time of Flight Positron Emission Tomography (ToF-PET) applications, where very good coincidence time resolution of the order of hundreds of picoseconds imply spatial resolution of the order of cm in the image reconstruction. The very fast rise time typical of the avalanche discharge improves the time resolution, but can be limited by the readout electronics and the technology used to construct the device. In this work the parameters of the equivalent circuit of the device that directly affect the pulse shape, namely the quenching resistance and capacitance and the diode and parasitic capacitances, were calculated. The mean rise time obtained with different preamplifiers was also measured.

Carbon Nanofiber versus Graphene-Based Stretchable Capacitive Touch Sensors for Artificial Electronic Skin.

Science.gov (United States)

Cataldi, Pietro; Dussoni, Simeone; Ceseracciu, Luca; Maggiali, Marco; Natale, Lorenzo; Metta, Giorgio; Athanassiou, Athanassia; Bayer, Ilker S

2018-02-01

Stretchable capacitive devices are instrumental for new-generation multifunctional haptic technologies particularly suited for soft robotics and electronic skin applications. A majority of elongating soft electronics still rely on silicone for building devices or sensors by multiple-step replication. In this study, fabrication of a reliable elongating parallel-plate capacitive touch sensor, using nitrile rubber gloves as templates, is demonstrated. Spray coating both sides of a rubber piece cut out of a glove with a conductive polymer suspension carrying dispersed carbon nanofibers (CnFs) or graphene nanoplatelets (GnPs) is sufficient for making electrodes with low sheet resistance values (≈10 Ω sq -1 ). The electrodes based on CnFs maintain their conductivity up to 100% elongation whereas the GnPs-based ones form cracks before 60% elongation. However, both electrodes are reliable under elongation levels associated with human joints motility (≈20%). Strikingly, structural damages due to repeated elongation/recovery cycles could be healed through annealing. Haptic sensing characteristics of a stretchable capacitive device by wrapping it around the fingertip of a robotic hand (ICub) are demonstrated. Tactile forces as low as 0.03 N and as high as 5 N can be easily sensed by the device under elongation or over curvilinear surfaces.

The effects of single bit quantization on direction of arrival estimation of UHF RFID tags

NARCIS (Netherlands)

Huiting, J.; Kokkeler, Andre B.J.; Smit, Gerardus Johannes Maria

2016-01-01

Phased arrays can be used to estimate the direction-of-arrival (DOA) of UHF RFID tags. To save on energy consumption and hardware costs, in this paper we explore the possibility of using single bit analog-to-digital converters for our phased array setup. This setup consists of an off-the-shelf

Synthesis of Silicon Nanocrystals in Microplasma Reactor

Science.gov (United States)

Nozaki, Tomohiro; Sasaki, Kenji; Ogino, Tomohisa; Asahi, Daisuke; Okazaki, Ken

Nanocrystalline silicon particles with a grain size of at least less than 10 nm are widely recognized as one of the key materials in optoelectronic devices, electrodes of lithium battery, bio-medical labels. There is also important character that silicon is safe material to the environment and easily gets involved in existing silicon technologies. To date, several synthesis methods such as sputtering, laser ablation, and plasma enhanced chemical vapor deposition (PECVD) based on low-pressure silane chemistry (SiH4) have been developed for precise control of size and density distributions of silicon nanocrystals. We explore the possibility of microplasma technologies for the efficient production of mono-dispersed nanocrystalline silicon particles in a micrometer-scale, continuous-flow plasma reactor operated at atmospheric pressure. Mixtures of argon, hydrogen, and silicon tetrachloride were activated using very high frequency (VHF = 144 MHz) power source in a capillary glass tube with a volume of less than 1 μ-liter. Fundamental plasma parameters of VHF capacitively coupled microplasma were characterized by optical emission spectroscopy, showing electron density of approximately 1015 cm-3 and rotational temperature of 1500 K, respectively. Such high-density non-thermal reactive plasma has a capability of decomposing silicon tetrachloride into atomic silicon to produce supersaturated atomic silicon vapor, followed by gas phase nucleation via three-body collision. The particle synthesis in high-density plasma media is beneficial for promoting nucleation process. In addition, further growth of silicon nuclei was able to be favorably terminated in a short-residence time reactor. Micro Raman scattering spectrum showed that as-deposited particles were mostly amorphous silicon with small fraction of silicon nanocrystals. Transmission electron micrograph confirmed individual silicon nanocrystals of 3-15 nm size. Although those particles were not mono-dispersed, they were

A Novel Technology for Motion Capture Using Passive UHF RFID Tags

DEFF Research Database (Denmark)

Krigslund, Rasmus; Popovski, Petar; Pedersen, Gert Frølund

2013-01-01

Although there are several existing methods for human motion capture, they all have important limitations and hence there is the need to explore fundamentally new approaches. Here we present a method based on a Radio Frequency IDentification (RFID) system with passive Ultra High Frequency (UHF...... walking. The reference joint angles for the validation were obtained by an optoelectronic system. Although the method is in its initial phase of development, the results of the validation are promising and show that the movement information can be extracted from the RFID response signals....

Additive advantage in characteristics of MIMCAPs on flexible silicon (100) fabric with release-first process

KAUST Repository

Ghoneim, Mohamed T.; Rojas, Jhonathan Prieto; Hussain, Aftab M.; Hussain, Muhammad Mustafa

2013-01-01

We report the inherent increase in capacitance per unit planar area of state-of-the art high-κ integrated metal/insulator/metal capacitors (MIMCAPs) fabricated on flexible silicon fabric with release-first process. We methodically study and show

Recent applications of UHF-MRI in the study of human brain function and structure : a review

NARCIS (Netherlands)

Van der Zwaag, W.; Schäfer, Andreas; Marques, José P; Turner, R.; Trampel, Robert

The increased availability of ultra-high-field (UHF) MRI has led to its application in a wide range of neuroimaging studies, which are showing promise in transforming fundamental approaches to human neuroscience. This review presents recent work on structural and functional brain imaging, at 7 T and

A new approach for two-terminal electronic memory devices - Storing information on silicon nanowires

Science.gov (United States)

Saranti, Konstantina; Alotaibi, Sultan; Paul, Shashi

2016-06-01

The work described in this paper focuses on the utilisation of silicon nanowires as the information storage element in flash-type memory devices. Silicon nanostructures have attracted attention due to interesting electrical and optical properties, and their potential integration into electronic devices. A detailed investigation of the suitability of silicon nanowires as the charge storage medium in two-terminal non-volatile memory devices are presented in this report. The deposition of the silicon nanostructures was carried out at low temperatures (less than 400 °C) using a previously developed a novel method within our research group. Two-terminal non-volatile (2TNV) memory devices and metal-insulator-semiconductor (MIS) structures containing the silicon nanowires were fabricated and an in-depth study of their characteristics was carried out using current-voltage and capacitance techniques.

An approach to evaluate capacitance, capacitive reactance and resistance of pivoted pads of a thrust bearing

Science.gov (United States)

Prashad, Har

1992-07-01

A theoretical approach is developed for determining the capacitance and active resistance between the interacting surfaces of pivoted pads and thrust collar, under different conditions of operation. It is shown that resistance and capacitive reactance of a thrust bearing decrease with the number of pads times the values of these parameters for an individual pad, and that capacitance increases with the number of pads times the capacitance of an individual pad. The analysis presented has a potential to diagnose the behavior of pivoted pad thrust bearings with the angle of tilt and the ratio of film thickness at the leading to trailing edge, by determining the variation of capacitance, resistance, and capacitive reactance.

Characterization of an x-ray hybrid CMOS detector with low interpixel capacitive crosstalk

OpenAIRE

Griffith, Christopher V.; Bongiorno, Stephen D.; Burrows, David N.; Falcone, Abraham D.; Prieskorn, Zachary R.

2012-01-01

We present the results of x-ray measurements on a hybrid CMOS detector that uses a H2RG ROIC and a unique bonding structure. The silicon absorber array has a 36{\\mu}m pixel size, and the readout array has a pitch of 18{\\mu}m; but only one readout circuit line is bonded to each 36x36{\\mu}m absorber pixel. This unique bonding structure gives the readout an effective pitch of 36{\\mu}m. We find the increased pitch between readout bonds significantly reduces the interpixel capacitance of the CMOS ...

Ferroelectric negative capacitance domain dynamics

Science.gov (United States)

Hoffmann, Michael; Khan, Asif Islam; Serrao, Claudy; Lu, Zhongyuan; Salahuddin, Sayeef; Pešić, Milan; Slesazeck, Stefan; Schroeder, Uwe; Mikolajick, Thomas

2018-05-01

Transient negative capacitance effects in epitaxial ferroelectric Pb(Zr0.2Ti0.8)O3 capacitors are investigated with a focus on the dynamical switching behavior governed by domain nucleation and growth. Voltage pulses are applied to a series connection of the ferroelectric capacitor and a resistor to directly measure the ferroelectric negative capacitance during switching. A time-dependent Ginzburg-Landau approach is used to investigate the underlying domain dynamics. The transient negative capacitance is shown to originate from reverse domain nucleation and unrestricted domain growth. However, with the onset of domain coalescence, the capacitance becomes positive again. The persistence of the negative capacitance state is therefore limited by the speed of domain wall motion. By changing the applied electric field, capacitor area or external resistance, this domain wall velocity can be varied predictably over several orders of magnitude. Additionally, detailed insights into the intrinsic material properties of the ferroelectric are obtainable through these measurements. A new method for reliable extraction of the average negative capacitance of the ferroelectric is presented. Furthermore, a simple analytical model is developed, which accurately describes the negative capacitance transient time as a function of the material properties and the experimental boundary conditions.

A miniature electrical capacitance tomograph

Science.gov (United States)

York, T. A.; Phua, T. N.; Reichelt, L.; Pawlowski, A.; Kneer, R.

2006-08-01

The paper describes a miniature electrical capacitance tomography system. This is based on a custom CMOS silicon integrated circuit comprising eight channels of signal conditioning electronics to source drive signals and measure voltages. Electrodes are deposited around a hole that is fabricated, using ultrasonic drilling, through a ceramic substrate and has an average diameter of 0.75 mm. The custom chip is interfaced to a host computer via a bespoke data acquisition system based on a microcontroller, field programmable logic device and wide shift register. This provides fast capture of up to 750 frames of data prior to uploading to the host computer. Data capture rates of about 6000 frames per second have been achieved for the eight-electrode sensor. This rate could be increased but at the expense of signal to noise. Captured data are uploaded to a PC, via a RS232 interface, for off-line imaging. Initial tests are reported for the static case involving 200 µm diameter rods that are placed in the sensor and for the dynamic case using the dose from an inhaler.

Hydrogen Incorporation during Aluminium Anodisation on Silicon Wafer Surfaces

International Nuclear Information System (INIS)

Lu, Pei Hsuan Doris; Strutzberg, Hartmuth; Wenham, Stuart; Lennon, Alison

2014-01-01

Hydrogen can act to reduce recombination at silicon surfaces for solar cell devices and consequently the ability of dielectric layers to provide a source of hydrogen for this purpose is of interest. However, due to the ubiquitous nature of hydrogen and its mobility, direct measurements of hydrogen incorporation in dielectric layers are challenging. In this paper, we report the use of secondary ion mass spectrometry measurements to show that deuterium from an electrolyte can be incorporated in an anodic aluminium oxide (AAO) layer and be introduced into an underlying amorphous silicon layer during anodisation of aluminium on silicon wafers. After annealing at 400 °C, the concentration of deuterium in the AAO was reduced by a factor of two, as the deuterium was re-distributed to the interface between the amorphous silicon and AAO and to the amorphous silicon. The assumption that hydrogen, from an aqueous electrolyte, could be similarly incorporated in AAO, is supported by the observation that the hydrogen content in the underlying amorphous silicon was increased by a factor of ∼ 3 after anodisation. Evidence for hydrogen being introduced into crystalline silicon after aluminium anodisation was provided by electrochemical capacitance voltage measurements indicating boron electrical deactivation in the underlying crystalline silicon. If introduced hydrogen can electrically deactivate dopant atoms at the surface, then it is reasonable to assume that it could also deactivate recombination-active states at the crystalline silicon interface therefore enabling higher minority carrier lifetimes in the silicon wafer

Aspheric surface measurement using capacitive probes

Science.gov (United States)

Tao, Xin; Yuan, Daocheng; Li, Shaobo

2017-02-01

With the application of aspheres in optical fields, high precision and high efficiency aspheric surface metrology becomes a hot research topic. We describe a novel method of non-contact measurement of aspheric surface with capacitive probe. Taking an eccentric spherical surface as the object of study, the averaging effect of capacitive probe measurement and the influence of tilting the capacitive probe on the measurement results are investigated. By comparing measurement results from simultaneous measurement of the capacitive probe and contact probe of roundness instrument, this paper indicates the feasibility of using capacitive probes to test aspheric surface and proposes the compensation method of measurement error caused by averaging effect and the tilting of the capacitive probe.

Miniaturized UHF, S-, and Ka-band RF MEMS Filters for Small Form Factor, High Performance EVA Radio, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — In Phase II of this SBIR, Harmonic Devices (HDI) proposes to develop miniaturized MEMS filters at UHF, S-band and Ka-band to address the requirements of NASA's...

Current and capacitance measurements as a fast diagnostic tool for evaluation of semiconductor parameters

CERN Document Server

Kemmer, J; Krause, N; Krieglmeyer, C; Yang Yi

2000-01-01

A fast qualitative method is described for evaluation of semiconductor parameters by analyzing both the capacitance/voltage (C/V) and current/voltage (I/V) characteristics of pn- or Schottky-diodes, which are fabricated on the material under investigation. The method is applied for measurement of recombination and generation lifetimes of minority charge carriers and for determination of doping profiles and distribution of active generation/recombination (G/R) centers after irradiation with Am-alpha particles and deep phosphorus implantation. Measurements on epitaxial silicon result in doping profiles and distributions of active impurities within the epi-layer.

Silicon dioxide with a silicon interfacial layer as an insulating gate for highly stable indium phosphide metal-insulator-semiconductor field effect transistors

Science.gov (United States)

Kapoor, V. J.; Shokrani, M.

1991-01-01

A novel gate insulator consisting of silicon dioxide (SiO2) with a thin silicon (Si) interfacial layer has been investigated for high-power microwave indium phosphide (InP) metal-insulator-semiconductor field effect transistors (MISFETs). The role of the silicon interfacial layer on the chemical nature of the SiO2/Si/InP interface was studied by high-resolution X-ray photoelectron spectroscopy. The results indicated that the silicon interfacial layer reacted with the native oxide at the InP surface, thus producing silicon dioxide, while reducing the native oxide which has been shown to be responsible for the instabilities in InP MISFETs. While a 1.2-V hysteresis was present in the capacitance-voltage (C-V) curve of the MIS capacitors with silicon dioxide, less than 0.1 V hysteresis was observed in the C-V curve of the capacitors with the silicon interfacial layer incorporated in the insulator. InP MISFETs fabricated with the silicon dioxide in combination with the silicon interfacial layer exhibited excellent stability with drain current drift of less than 3 percent in 10,000 sec, as compared to 15-18 percent drift in 10,000 sec for devices without the silicon interfacial layer. High-power microwave InP MISFETs with Si/SiO2 gate insulators resulted in an output power density of 1.75 W/mm gate width at 9.7 GHz, with an associated power gain of 2.5 dB and 24 percent power added efficiency.

Split-Capacitance and Conductance-Frequency Characteristics of SOI Wafers in Pseudo-MOSFET Configuration

KAUST Repository

Pirro, Luca

2015-09-01

Recent experimental results have demonstrated the possibility of characterizing silicon-on-insulator (SOI) wafers through split C-V measurements in the pseudo-MOSFET configuration. This paper analyzes the capacitance and conductance versus frequency characteristics. We discuss the conditions under which it is possible to extract interface trap density in bare SOI wafers. The results indicate, through both measurements and simulations, that the signature due to interface trap density is present in small-area samples, but is masked by the RC response of the channel in regular, large-area ones, making the extraction in standard samples problematic. © 1963-2012 IEEE.

Split-Capacitance and Conductance-Frequency Characteristics of SOI Wafers in Pseudo-MOSFET Configuration

KAUST Repository

Pirro, Luca; Diab, Amer El Hajj; Ionica, Irina; Ghibaudo, Gerard; Faraone, Lorenzo; Cristoloveanu, Sorin

2015-01-01

Recent experimental results have demonstrated the possibility of characterizing silicon-on-insulator (SOI) wafers through split C-V measurements in the pseudo-MOSFET configuration. This paper analyzes the capacitance and conductance versus frequency characteristics. We discuss the conditions under which it is possible to extract interface trap density in bare SOI wafers. The results indicate, through both measurements and simulations, that the signature due to interface trap density is present in small-area samples, but is masked by the RC response of the channel in regular, large-area ones, making the extraction in standard samples problematic. © 1963-2012 IEEE.

Efficiency of Capacitively Loaded Converters

DEFF Research Database (Denmark)

Andersen, Thomas; Huang, Lina; Andersen, Michael A. E.

2012-01-01

This paper explores the characteristic of capacitance versus voltage for dielectric electro active polymer (DEAP) actuator, 2kV polypropylene film capacitor as well as 3kV X7R multi layer ceramic capacitor (MLCC) at the beginning. An energy efficiency for capacitively loaded converters...... is introduced as a definition of efficiency. The calculated and measured efficiency curves for charging DEAP actuator, polypropylene film capacitor and X7R MLCC are provided and compared. The attention has to be paid for the voltage dependent capacitive load, like X7R MLCC, when evaluating the charging...... polypropylene film capacitor can be the equivalent capacitive load. Because of the voltage dependent characteristic, X7R MLCC cannot be used to replace the DEAP actuator. However, this type of capacitor can be used to substitute the capacitive actuator with voltage dependent property at the development phase....

Low-temperature radiation damage in silicon - 1: Annealing studies on N-type material

International Nuclear Information System (INIS)

Awadelkarim, O.O.

1986-07-01

The presence of electrically active defects in electron-irradiated P-doped n-type silicon was monitored using capacitance and loss factor measurements. Irradiations were performed at temperatures c - 0.14) eV and (E c - 0.24) eV in the gap are ascribed to the carbon interstitial and the divacancy, respectively. (author)

A novel sandwich differential capacitive accelerometer with symmetrical double-sided serpentine beam-mass structure

International Nuclear Information System (INIS)

Xiao, D B; Li, Q S; Hou, Z Q; Wang, X H; Chen, Z H; Xia, D W; Wu, X Z

2016-01-01

This paper presents a novel differential capacitive silicon micro-accelerometer with symmetrical double-sided serpentine beam-mass sensing structure and glass–silicon–glass sandwich structure. The symmetrical double-sided serpentine beam-mass sensing structure is fabricated with a novel pre-buried mask fabrication technology, which is convenient for manufacturing multi-layer sensors. The glass–silicon–glass sandwich structure is realized by a double anodic bonding process. To solve the problem of the difficulty of leading out signals from the top and bottom layer simultaneously in the sandwich sensors, a silicon pillar structure is designed that is inherently simple and low-cost. The prototype is fabricated and tested. It has low noise performance (the peak to peak value is 40 μg) and μg-level Allan deviation of bias (2.2 μg in 1 h), experimentally demonstrating the effectiveness of the design and the novel fabrication technology. (paper)

Development of radiation hard microstrip detectors for the CBM silicon tracking system

Energy Technology Data Exchange (ETDEWEB)

Chatterji, Sudeep [GSI, Darmstadt (Germany)

2010-07-01

Radiation damage in Silicon microstrip detectors is of the one main concerns for the development of the Silicon Tracking System (STS) in the planned Compressed Baryonic Matter (CBM) experiment at FAIR. The STS will consist of Double Sided Silicon Strip Detectors (DSSD) having pitch around 60 {mu}m, width 20 {mu}m, stereo angle of {+-}7.5{sup 0} on n and p sides with double metallization on either side making it challenging to fabricate.We are using 3-dimensional TCAD simulation tools from SYNOPSYS to carry out process (using Sentaurus Process) and device (using Sentaurus Device) simulations.We have simulated the impact of radiation damage in DSSDs by changing the effective carrier concentration (N{sub eff}) with fluence using the Hamburg model. The change in minority carrier life time has been taken into account using the Kraners model and the Perugia trap model has been used to simulate the traps. We have also extracted macroscopic parameters like Coupling Capacitance, Interstrip Capacitance (both DC and AC), Interstrip Resistance of DSSDs using Mixed Mode simulation (using SPICE with Sentaurus Device) and studied the variation of these parameters with fluence. The simulation results have been compared to the experimental results. We also simulated transients by passing a Heavy Ion through a DSSD and studied the charge collection performance.

Capacitance of circular patch resonator

International Nuclear Information System (INIS)

Miano, G.; Verolino, L.; Naples Univ.; Panariello, G.; Vaccaro, V.G.; Naples Univ.

1995-11-01

In this paper the capacitance of the circular microstrip patch resonator is computed. It is shown that the electrostatic problem can be formulated as a system of dual integral equations, and the most interesting techniques of solutions of these systems are reviewed. Some useful approximated formulas for the capacitance are derived and plots of the capacitance are finally given in a wide range of dielectric constants

Effect of Slice Error of Glass on Zero Offset of Capacitive Accelerometer

Science.gov (United States)

Hao, R.; Yu, H. J.; Zhou, W.; Peng, B.; Guo, J.

2018-03-01

Packaging process had been studied on capacitance accelerometer. The silicon-glass bonding process had been adopted on sensor chip and glass, and sensor chip and glass was adhered on ceramic substrate, the three-layer structure was curved due to the thermal mismatch, the slice error of glass lead to asymmetrical curve of sensor chip. Thus, the sensitive mass of accelerometer deviated along the sensitive direction, which was caused in zero offset drift. It was meaningful to confirm the influence of slice error of glass, the simulation results showed that the zero output drift was 12.3×10-3 m/s2 when the deviation was 40μm.

Development of micro capacitive accelerometer for subsurface microseismic measurement; Micromachining ni yoru chika danseiha kenshutsu no tame no silicon yoryogata kasokudo sensor no seisaku

Energy Technology Data Exchange (ETDEWEB)

Nishizawa, M; Niitsuma, H; Esashi, M [Tohoku University, Sendai (Japan). Faculty of Engineering

1997-05-27

A silicon capacitive accelerometer was fabricated to detect subsurface elastic waves by using micromachining technology. Characteristics required for it call for capability of detecting acceleration with amplitudes from 0.1 to 1 gal and flat amplitude characteristics in frequency bands of 10 Hz to several kHz. For the purpose of measuring transition phenomena, linear phase characteristics in the required bands must be guaranteed, cross sensitivity must be small, and resistance to water, pressure and heat is demanded. Sensitivity of the sensor is determined finally by noise level in a detection circuit. The sensor`s minimum detection capability was 40 mgal in the case of the distance between a weight and an electrode being 3 {mu}m. This specification value is a value realizable by the current micromachining technology. Dimensions for the weight and other members were decided with the natural frequency to make band width 2 kHz set to 4 kHz. Completion of the product has not been achieved yet, however, because of a problem that the weight gets stuck on the electrode plate in anode bonding in the assembly process. 7 refs., 5 figs., 1 tab.

Highly sensitive micromachined capacitive pressure sensor with reduced hysteresis and low parasitic capacitance

DEFF Research Database (Denmark)

Pedersen, Thomas; Fragiacomo, Giulio; Hansen, Ole

2009-01-01

This paper describes the design and fabrication of a capacitive pressure sensor that has a large capacitance signal and a high sensitivity of 76 pF/bar in touch mode operation. Due to the large signal, problems with parasitic capacitances are avoided and hence it is possible to integrate the sensor...... bonding to create vacuum cavities. The exposed part of the sensor is perfectly flat such that it can be coated with corrosion resistant thin films. Hysteresis is an inherent problem in touch mode capacitive pressure sensors and a technique to significantly reduce it is presented....... with a discrete components electronics circuit for signal conditioning. Using an AC bridge electronics circuit a resolution of 8 mV/mbar is achieved. The large signal is obtained due to a novel membrane structure utilizing closely packed hexagonal elements. The sensor is fabricated in a process based on fusion...

Capacitive Biosensors and Molecularly Imprinted Electrodes.

Science.gov (United States)

Ertürk, Gizem; Mattiasson, Bo

2017-02-17

Capacitive biosensors belong to the group of affinity biosensors that operate by registering direct binding between the sensor surface and the target molecule. This type of biosensors measures the changes in dielectric properties and/or thickness of the dielectric layer at the electrolyte/electrode interface. Capacitive biosensors have so far been successfully used for detection of proteins, nucleotides, heavy metals, saccharides, small organic molecules and microbial cells. In recent years, the microcontact imprinting method has been used to create very sensitive and selective biorecognition cavities on surfaces of capacitive electrodes. This chapter summarizes the principle and different applications of capacitive biosensors with an emphasis on microcontact imprinting method with its recent capacitive biosensor applications.

Glow discharge-deposited amorphous silicon films for low-cost solar cells

Energy Technology Data Exchange (ETDEWEB)

Grabmaier, J G; Plaettner, R D; Stetter, W [Siemens A.G., Muenchen (Germany, F.R.). Forschungslaboratorien

1980-01-01

Due to their high absorption constant, glow discharge-deposited amorphous silicon (a-Si) films are of great interest for low-cost solar cells. Using SiH/sub 4/ and SiX/sub 4//H/sub 2/ (X = Cl or F) gas mixtures in an inductively or capacitively excited reactor, a-Si films with thicknesses up to several micrometers were deposited on substrates of glass, silica and silicon. The optical and electrical properties of the films were determined by measuring the IR absorption spectra, dark conductivity, photoconductivity, and photoluminescence. Hydrogen, chlorine, or fluorine were incorporated in the films in order to passivate dangling bonds in the amorphous network.

Development of innovative silicon radiation detectors

CERN Document Server

Balbuena, JuanPablo

Silicon radiation detectors fabricated at the IMB-CNM (CSIC) Clean Room facilities using the most innovative techniques in detector technology are presented in this thesis. TCAD simulation comprises an important part in this work as becomes an essential tool to achieve exhaustive performance information of modelled detectors prior their fabrication and subsequent electrical characterization. Radiation tolerance is also investigated in this work using TCAD simulations through the potential and electric field distributions, leakage current and capacitance characteristics and the response of the detectors to the pass of different particles for charge collection efficiencies. Silicon detectors investigated in this thesis were developed for specific projects but also for applications in experiments which can benefit from their improved characteristics, as described in Chapter 1. Double-sided double type columns 3D (3D-DDTC) detectors have been developed under the NEWATLASPIXEL project in the framework of the CERN ...

Electromagnetic fields (UHF) increase voltage sensitivity of membrane ion channels; possible indication of cell phone effect on living cells.

Science.gov (United States)

Ketabi, N; Mobasheri, H; Faraji-Dana, R

2015-03-01

The effects of ultra high frequency (UHF) nonionizing electromagnetic fields (EMF) on the channel activities of nanopore forming protein, OmpF porin, were investigated. The voltage clamp technique was used to study the single channel activity of the pore in an artificial bilayer in the presence and absence of the electromagnetic fields at 910 to 990 MHz in real time. Channel activity patterns were used to address the effect of EMF on the dynamic, arrangement and dielectric properties of water molecules, as well as on the hydration state and arrangements of side chains lining the channel barrel. Based on the varied voltage sensitivity of the channel at different temperatures in the presence and absence of EMF, the amount of energy transferred to nano-environments of accessible groups was estimated to address the possible thermal effects of EMF. Our results show that the effects of EMF on channel activities are frequency dependent, with a maximum effect at 930 MHz. The frequency of channel gating and the voltage sensitivity is increased when the channel is exposed to EMF, while its conductance remains unchanged at all frequencies applied. We have not identified any changes in the capacitance and permeability of membrane in the presence of EMF. The effect of the EMF irradiated by cell phones is measured by Specific Absorption Rate (SAR) in artificial model of human head, Phantom. Thus, current approach applied to biological molecules and electrolytes might be considered as complement to evaluate safety of irradiating sources on biological matter at molecular level.

Nanoscale capacitance: A quantum tight-binding model

Science.gov (United States)

Zhai, Feng; Wu, Jian; Li, Yang; Lu, Jun-Qiang

2017-01-01

Landauer-Buttiker formalism with the assumption of semi-infinite electrodes as reservoirs has been the standard approach in modeling steady electron transport through nanoscale devices. However, modeling dynamic electron transport properties, especially nanoscale capacitance, is a challenging problem because of dynamic contributions from electrodes, which is neglectable in modeling macroscopic capacitance and mesoscopic conductance. We implement a self-consistent quantum tight-binding model to calculate capacitance of a nano-gap system consisting of an electrode capacitance C‧ and an effective capacitance Cd of the middle device. From the calculations on a nano-gap made of carbon nanotube with a buckyball therein, we show that when the electrode length increases, the electrode capacitance C‧ moves up while the effective capacitance Cd converges to a value which is much smaller than the electrode capacitance C‧. Our results reveal the importance of electrodes in modeling nanoscale ac circuits, and indicate that the concepts of semi-infinite electrodes and reservoirs well-accepted in the steady electron transport theory may be not applicable in modeling dynamic transport properties.

Capacitive Sensing of Glucose in Electrolytes Using Graphene Quantum Capacitance Varactors.

Science.gov (United States)

Zhang, Yao; Ma, Rui; Zhen, Xue V; Kudva, Yogish C; Bühlmann, Philippe; Koester, Steven J

2017-11-08

A novel graphene-based variable capacitor (varactor) that senses glucose based on the quantum capacitance effect was successfully developed. The sensor utilizes a metal-oxide-graphene varactor device structure that is inherently compatible with passive wireless sensing, a key advantage for in vivo glucose sensing. The graphene varactors were functionalized with pyrene-1-boronic acid (PBA) by self-assembly driven by π-π interactions. Successful surface functionalization was confirmed by both Raman spectroscopy and capacitance-voltage characterization of the devices. Through glucose binding to the PBA, the glucose concentration in the buffer solutions modulates the level of electrostatic doping of the graphene surface to different degrees, which leads to capacitance changes and Dirac voltage shifts. These responses to the glucose concentration were shown to be reproducible and reversible over multiple measurement cycles, suggesting promise for eventual use in wireless glucose monitoring.

Novel photodefined polymer-embedded vias for silicon interposers

International Nuclear Information System (INIS)

Thadesar, Paragkumar A; Bakir, Muhannad S

2013-01-01

This paper describes the fabrication and characterization of novel photodefined polymer-embedded vias for silicon interposers. The fabricated polymer-embedded vias can help obtain ∼3.8× reduction in via-to-via capacitance as well as a reduction in insertion loss compared to TSVs with a silicon dioxide liner. Polymer-embedded vias 100 μm in diameter, 270 μm tall and at 250 μm pitch were fabricated. Resistance and leakage measurements were performed for the fabricated polymer-embedded vias. The average value of the measured resistance for 20 polymer-embedded vias is 2.54 mΩ and the maximum measured via-to-via leakage current for 10 pairs of polymer-embedded vias is 80.8 pA for an applied voltage of 200 V. (paper)

Deep levels induced by low energy B+ implantation into Ge-preamorphised silicon in correlation with end of range formation

International Nuclear Information System (INIS)

Benzohra, Mohamed; Olivie, Francois; Idrissi-Benzohra, Malika; Ketata, Kaouther; Ketata, Mohamed

2002-01-01

It is well established that low energy B + ion implantation into Ge- (or Si) implantation pre-amorphised silicon allows ultra-shallow p + n junctions formation. However, this process is known to generate defects such as dislocation loops, vacancies and interstitials which can act as vehicles to different mechanisms inducing electrically active levels into the silicon bulk. The junctions studied have been obtained using 3 keV/10 15 cm -2 B + implantation into Ge-implantation pre-amorphised substrates and into a reference crystalline substrate. Accurate measurements using deep level transient spectroscopy (DLTS) and isothermal transient capacitance ΔC(t,T) were performed to characterise these levels. Such knowledge is crucial to improve the device characteristics. In order to sweep the silicon band gap, various experimental conditions were considered. The analysis of DLTS spectra have first showed three deep levels associated to secondary induced defects. Their concentration profiles were derived from isothermal transient capacitance at depths up to 3.5 μm into the silicon bulk and allowed us to detect a new deep level. The evolution of such defect distribution in correlation with the technological steps is discussed. The end of range (EOR) defect influence on electrical activity of secondary induced defects in ultra-shallow p + n diodes is clearly demonstrated

CPW-Fed Wideband Circular Polarized Antenna for UHF RFID Applications

Directory of Open Access Journals (Sweden)

Sun-Woong Kim

2017-01-01

Full Text Available We propose a wide bandwidth antenna with a circular polarization for universal Ultra High Frequency (UHF radio-frequency identification (RFID reader applications. To achieve a wide 3 dB axial ratio (AR bandwidth, three T-shaped microstrip lines are inserted into the ground plane. The measured impedance bandwidth of the proposed antenna is 480 MHz and extends from 660 to 1080 MHz, and the 3 dB AR bandwidth is 350 MHz and extends from 800 to 1155 MHz. The radiation pattern is a bidirectional pattern with a maximum antenna gain of 3.67 dBi. The overall size of the proposed antenna is 114 × 114 × 0.8 mm3.

Comparative Method for Indirect Sensitivity Measurement of UHF RFID Reader with Respect to Interoperability and Conformance Requirements

Directory of Open Access Journals (Sweden)

Lukas Kypus

2014-01-01

Full Text Available There is never-ending race for the competitive advantage that forces RFID technology service integrators to focus more on used technology qualitative aspects and theirs impacts inside RFID ecosystem. This paper contributes to UHF RFID reader qualitative parameters evaluation and assessment problematic. It presents and describes in details indirect method and procedure of sensitivity measurement created for UHF RFID readers. We applied this method on RFID readers within prepared test environment and confirmed long term intention and recognized trend. Due to regulations limitations, there is not possible to increase output power over defined limits, but there are possibilities to influence reader sensitivity. Our proposal is to use customized comparative measurement method with insertion loss compensation for return link. Beside the main goal achievement, results show as well the qualitative status of development snapshot of reader. Method and following experiment helped us to gain an external view, current values of important parameters and motivation we want to follow up on as well as compared developed reader with its commercial competitors.

Biasing of Capacitive Micromachined Ultrasonic Transducers.

Science.gov (United States)

Caliano, Giosue; Matrone, Giulia; Savoia, Alessandro Stuart

2017-02-01

Capacitive micromachined ultrasonic transducers (CMUTs) represent an effective alternative to piezoelectric transducers for medical ultrasound imaging applications. They are microelectromechanical devices fabricated using silicon micromachining techniques, developed in the last two decades in many laboratories. The interest for this novel transducer technology relies on its full compatibility with standard integrated circuit technology that makes it possible to integrate on the same chip the transducers and the electronics, thus enabling the realization of extremely low-cost and high-performance devices, including both 1-D or 2-D arrays. Being capacitive transducers, CMUTs require a high bias voltage to be properly operated in pulse-echo imaging applications. The typical bias supply residual ripple of high-quality high-voltage (HV) generators is in the millivolt range, which is comparable with the amplitude of the received echo signals, and it is particularly difficult to minimize. The aim of this paper is to analyze the classical CMUT biasing circuits, highlighting the features of each one, and to propose two novel HV generator architectures optimized for CMUT biasing applications. The first circuit proposed is an ultralow-residual ripple (generator that uses an extremely stable sinusoidal power oscillator topology. The second circuit employs a commercially available integrated step-up converter characterized by a particularly efficient switching topology. The circuit is used to bias the CMUT by charging a buffer capacitor synchronously with the pulsing sequence, thus reducing the impact of the switching noise on the received echo signals. The small area of the circuit (about 1.5 cm 2 ) makes it possible to generate the bias voltage inside the probe, very close to the CMUT, making the proposed solution attractive for portable applications. Measurements and experiments are shown to demonstrate the effectiveness of the new approaches presented.

Carbon flow electrodes for continuous operation of capacitive deionization and capacitive mixing energy generation

NARCIS (Netherlands)

Porada, S.; Hamelers, H.V.M.; Bryjak, M.; Presser, V.; Biesheuvel, P.M.; Weingarth, D.

2014-01-01

Capacitive technologies, such as capacitive deionization and energy harvesting based on mixing energy (“capmix” and “CO2 energy”), are characterized by intermittent operation: phases of ion electrosorption from the water are followed by system regeneration. From a system application point of view,

Linear thermal expansion measurements on silicon from 6 to 340 K

International Nuclear Information System (INIS)

Lyon, K.G.; Salinger, G.L.; Swenson, C.A.; White, G.K.

1977-01-01

Linear thermal expansion measurements have been carried out from 6 to 340 K on a high-purity silicon sample using a linear absolute capacitance dilatometer. The accuracy of the measurements varies from +- 0.01 x 10 -8 K -1 at the lowest temperatures to +- 0.1 x 10 -8 K -1 or 0.1%, whichever is greater, near room temperature, and is sufficient to establish silicon as a thermal expansion standard for these temperatures. The agreement with previous data is satisfactory at low temperatures and excellent above room temperature where laser-interferometry data of comparable accuracy exist. Thermal expansions calculated from ultrasonic and heat-capacity data are preferred below 13 K where experimental problems occurred

A fully integrated UHF RFID reader SoC for handheld applications in the 0.18 {mu}m CMOS process

Energy Technology Data Exchange (ETDEWEB)

Wang Jingchao; Zhang Chun; Wang Zhihua, E-mail: wangjc@gmail.co [Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

2010-08-15

A low cost fully integrated single-chip UHF radio frequency identification (RFID) reader SoC for short distance handheld applications is presented. The SoC integrates all building blocks-including an RF transceiver, a PLL frequency synthesizer, a digital baseband and an MCU-in a 0.18 {mu}m CMOS process. A high-linearity RX front-end is designed to handle the large self-interferer. A class-E power amplifier with high power efficiency is also integrated to fulfill the function of a UHF passive RFID reader. The measured maximum output power of the transmitter is 20.28 dBm and the measured receiver sensitivity is -60 dBm. The digital baseband including MCU core consumes 3.91 mW with a clock of 10 MHz and the analog part including power amplifier consumes 368.4 mW. The chip has a die area of 5.1 x 3.8 mm{sup 2} including pads. (semiconductor integrated circuits)

A fully integrated UHF RFID reader SoC for handheld applications in the 0.18 μm CMOS process

International Nuclear Information System (INIS)

Wang Jingchao; Zhang Chun; Wang Zhihua

2010-01-01

A low cost fully integrated single-chip UHF radio frequency identification (RFID) reader SoC for short distance handheld applications is presented. The SoC integrates all building blocks-including an RF transceiver, a PLL frequency synthesizer, a digital baseband and an MCU-in a 0.18 μm CMOS process. A high-linearity RX front-end is designed to handle the large self-interferer. A class-E power amplifier with high power efficiency is also integrated to fulfill the function of a UHF passive RFID reader. The measured maximum output power of the transmitter is 20.28 dBm and the measured receiver sensitivity is -60 dBm. The digital baseband including MCU core consumes 3.91 mW with a clock of 10 MHz and the analog part including power amplifier consumes 368.4 mW. The chip has a die area of 5.1 x 3.8 mm 2 including pads. (semiconductor integrated circuits)

SOI silicon on glass for optical MEMS

DEFF Research Database (Denmark)

Larsen, Kristian Pontoppidan; Ravnkilde, Jan Tue; Hansen, Ole

2003-01-01

and a final sealing at the interconnects can be performed using a suitable polymer. Packaged MEMS on glass are advantageous within Optical MEMS and for sensitive capacitive devices. We report on experiences with bonding SOI to Pyrex. Uniform DRIE shallow and deep etching was achieved by a combination......A newly developed fabrication method for fabrication of single crystalline Si (SCS) components on glass, utilizing Deep Reactive Ion Etching (DRIE) of a Silicon On Insulator (SOI) wafer is presented. The devices are packaged at wafer level in a glass-silicon-glass (GSG) stack by anodic bonding...... of an optimized device layout and an optimized process recipe. The behavior of the buried oxide membrane when used as an etch stop for the through-hole etch is described. No harmful buckling or fracture of the membrane is observed for an oxide thickness below 1 μm, but larger and more fragile released structures...

A new detector concept for silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Sadigov, A., E-mail: saazik@yandex.ru [National Nuclear Research Center, Baku (Azerbaijan); Ahmadov, F.; Ahmadov, G. [National Nuclear Research Center, Baku (Azerbaijan); Ariffin, A.; Khorev, S. [Zecotek Photonics Inc., Vancouver (Canada); Sadygov, Z. [National Nuclear Research Center, Baku (Azerbaijan); Joint Institute for Nuclear Research, Dubna (Russian Federation); Suleymanov, S. [National Nuclear Research Center, Baku (Azerbaijan); Zerrouk, F. [Zecotek Photonics Inc., Vancouver (Canada); Madatov, R. [Institute of Radiation Problems, Baku (Azerbaijan)

2016-07-11

A new design and principle of operation of silicon photomultipliers are presented. The new design comprises a semiconductor substrate and an array of independent micro-phototransistors formed on the substrate. Each micro-phototransistor comprises a photosensitive base operating in Geiger mode and an individual micro-emitter covering a small part of the base layer, thereby creating, together with this latter, a micro-transistor. Both micro-emitters and photosensitive base layers are connected with two respective independent metal grids via their individual micro-resistors. The total value of signal gain in the proposed silicon photomultiplier is a result of both the avalanche gain in the base layer and the corresponding gain in the micro-transistor. The main goals of the new design are: significantly lower both optical crosstalk and after-pulse effects at high signal amplification, improve speed of single photoelectron pulse formation, and significantly reduce the device capacitance.

Studies of frequency dependent C-V characteristics of neutron irradiated p+-n silicon detectors

International Nuclear Information System (INIS)

Li, Zheng; Kraner, H.W.

1990-10-01

Frequency-dependent capacitance-voltage fluence (C-V) characteristics of neutron irradiated high resistivity silicon p + -n detectors have been observed up to a fluence of 8.0 x 10 12 n/cm 2 . It has been found that frequency dependence of the deviation of the C-V characteristic (from its normal V -1/2 dependence), is strongly dependent on the ratio of the defect density and the effective doping density N t /N' d . As the defect density approaches the effective dopant density, or N t /N' d → 1, the junction capacitance eventually assumes the value of the detector geometry capacitance at high frequencies (f ≤ 10 5 Hz), independent of voltage. A two-trap-level model using the concept of quasi-fermi levels has been developed, which predicts both the effects of C-V frequency dependence and dopant compensation observed in this study

High-Pressure Water-Vapor Annealing for Enhancement of a-Si:H Film Passivation of Silicon Surface

International Nuclear Information System (INIS)

Guo Chun-Lin; Wang Lei; Zhang Yan-Rong; Zhou Hai-Feng; Liang Feng; Yang Zhen-Hui; Yang De-Ren

2014-01-01

We investigate the effect of amorphous hydrogenated silicon (a-Si:H) films passivated on silicon surfaces based on high-pressure water-vapor annealing (HWA). The effective carrier lifetime of samples reaches the maximum value after 210°C, 90min HWA. Capacitance-voltage measurement reveals that the HWA not only greatly reduces the density of interface states (D it ), but also decreases the fixed charges (Q fixed ) mainly caused by bulk defects. The change of hydrogen and oxygen in the film is measured by a spectroscopic ellipsometer and a Fourier-transform infrared (FTIR) spectrometer. All these results show that HWA is a useful method to improve the passivation effect of a-Si:H films deposited on silicon surfaces

Design of a charge sensitive preamplifier on high resistivity silicon

International Nuclear Information System (INIS)

Radeka, V.; Rehak, P.; Rescia, S.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Strueder, L.; Kemmer, J.

1987-01-01

A low noise, fast charge sensitive preamplifier was designed on high resistivity, detector grade silicon. It is built at the surface of a fully depleted region of n-type silicon. This allows the preamplifier to be placed very close to a detector anode. The preamplifier uses the classical input cascode configuration with a capacitor and a high value resistor in the feedback loop. The output stage of the preamplifier can drive a load up to 20pF. The power dissipation of the preamplifier is 13mW. The amplifying elements are ''Single Sided Gate JFETs'' developed especially for this application. Preamplifiers connected to a low capacitance anode of a drift type detector should achieve a rise time of 20ns and have an equivalent noise charge (ENC), after a suitable shaping, of less than 50 electrons. This performance translates to a position resolution better than 3μm for silicon drift detectors. 6 refs., 9 figs

Studies on deep electronic levels in silicon and aluminium gallium arsenide alloys

International Nuclear Information System (INIS)

Pettersson, H.

1993-01-01

This thesis reports on investigations of the electrical and optical properties of deep impurity centers, related to the transition metals (TMs) Ti, Mo, W, V and Ni, in silicon. Emission rates, capture cross sections and photoionization cross sections for these impurities were determined by means of various Junction Space Charge Techniques (JSCTs), such as Deep Level Transient Spectroscopy (DLTS), dark capacitance transient and photo capacitance transient techniques. Changes in Gibbs free energy as a function of temperature were calculated for all levels. From this temperature dependence, the changes in enthalpy and entropy involved in the electron and hole transitions were deduced. The influence of high electric fields on the electronic levels in chalcogen-doped silicon were investigated using the dark capacitance transient technique. The enhancement of the electron emission from the deep centers indicated a more complex field enhancement model than the expected Poole-Frenkel effect for coulombic potentials. The possibility to determine charge states of defects using the Poole-Frenkel effect, as often suggested, is therefore questioned. The observation of a persistent decrease of the dark conductivity due to illumination in simplified AlGaAs/GaAs high Electron Mobility Transistors (HEMTs) over the temperature range 170K< T<300K is reported. A model for this peculiar behavior, based on the recombination of electrons in the two-dimensional electron gas (2DEG) located at the AlGaAs/GaAs interface with holes generated by a two-step excitation process via the deep EL2 center in the GaAs epilayer, is put forward

Effects of wind turbines on UHF television reception: field tests in Denmark

International Nuclear Information System (INIS)

Sorenson, B.

1992-01-01

As a result of a planning application for a windfarm comprising 20 wind turbines at Tynewydd Farm, Gilfach Goch in Mid Glamorgan, a report discussing any detrimental effects the proposal might have on u.h.f. television reception was produced. In order to make the report as definitive as possible, it was decided to carry out field tests on the exact model of wind turbine to be used at Tynewydd. This required a field trip to Denmark, and the opportunity was taken to make measurements on two other models of turbine at the same time. This report presents the analysis of the results for all three turbines. (author)

Letter to the Editor UHF electromagnetic emission stimulated by HF pumping of the ionosphere

Directory of Open Access Journals (Sweden)

S. M. Grach

2002-10-01

Full Text Available UHF electromagnetic emission (with a frequency near 600 MHz from the F-region of the ionosphere pumped by an HF powerful radio wave is revealed. Possible mechanisms of the emission excitation, such as plasma mode con-version, scattering or Earth thermal noise emission off the plasma density irregularities, bremsstrahlung and excitation of high Rydberg states of the neutral particles by the accelerated electrons are discussed.Key words. Ionosphere (active experiments; wave-particle interactions – Solar physics, astrophysics, and astronomy (radio emissions

Letter to the Editor UHF electromagnetic emission stimulated by HF pumping of the ionosphere

Directory of Open Access Journals (Sweden)

E. N. Sergeev

Full Text Available UHF electromagnetic emission (with a frequency near 600 MHz from the F-region of the ionosphere pumped by an HF powerful radio wave is revealed. Possible mechanisms of the emission excitation, such as plasma mode con-version, scattering or Earth thermal noise emission off the plasma density irregularities, bremsstrahlung and excitation of high Rydberg states of the neutral particles by the accelerated electrons are discussed.Key words. Ionosphere (active experiments; wave-particle interactions – Solar physics, astrophysics, and astronomy (radio emissions

Wireless Capacitive Pressure Sensor Operating up to 400 Celcius from 0 to 100 psi Utilizing Power Scavenging

Science.gov (United States)

Scardelletti, Maximilian C.; Ponchak, George E.; Harsh, Kevin; Mackey, Jonathan A.; Meredith, Roger D.; Zorman, Christian A.; Beheim, Glenn M.; Dynys, Frederick W.; Hunter, Gary W.

2014-01-01

In this paper, a wireless capacitive pressure sensor developed for the health monitoring of aircraft engines has been demonstrated. The sensing system is composed of a Clapp-type oscillator that operates at 131 MHz. The Clapp oscillator is fabricated on a alumina substrate and consists of a Cree SiC (silicon carbide) MESFET (Metal Semiconductor Field Effect Transistors), this film inductor, Compex chip capacitors and Sporian Microsystem capacitive pressure sensor. The resonant tank circuit within the oscillator is made up of the pressure sensor and a spiral thin film inductor, which is used to magnetically couple the wireless pressure sensor signal to a coil antenna placed over 1 meter away. 75% of the power used to bias the sensing system is generated from thermoelectric power modules. The wireless pressure sensor is operational at room temperature through 400 C from 0 to 100 psi and exhibits a frequency shift of over 600 kHz.

Study of the radiation damage of silicon photomultipliers

Energy Technology Data Exchange (ETDEWEB)

Nitschke, Michael; Chmill, Valery; Garutti, Erika; Klanner, Robert; Schwandt, Joern [Institute for Experimental Physics, Hamburg University, Luruper Chaussee 149, D-22761 Hamburg (Germany)

2016-07-01

Radiation damage significantly changes the performance of silicon photomultipliers (SiPM). In this work, we first have characterized KETEK SiPMs with a pixel size of 15 x 15 μm{sup 2} using I-V (current-voltage), C/G-V/f (capacitance/impedance-voltage/frequency) and Q-V (charge-voltage) measurements with and without illumination with blue light of 470 nm from an LED. The SiPM parameters determined are DCR (dark count rate), relative PDE (photon detection efficiency), G (Gain), XT (cross-talk), Geiger breakdown characteristics, C{sub pix} (pixel capacitance) and R{sub q} (quenching resistance). Following this first characterization, the SiPMs were irradiated using reactor neutrons with fluences of 10{sup 9}, 10{sup 10}, 10{sup 11}, 5 . 10{sup 11}, and 10{sup 12} n/cm{sup 2}. Afterwards, the same measurements were repeated, and the dependence of the SiPM parameters on neutron fluence was determined. The results are used to optimize the radiation tolerance of SiPMs.

Ultrafast triggered transient energy storage by atomic layer deposition into porous silicon for integrated transient electronics

Science.gov (United States)

Douglas, Anna; Muralidharan, Nitin; Carter, Rachel; Share, Keith; Pint, Cary L.

2016-03-01

Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics.Here we demonstrate the first on-chip silicon-integrated rechargeable transient power source based on atomic layer deposition (ALD) coating of vanadium oxide (VOx) into porous silicon. A stable specific capacitance above 20 F g-1 is achieved until the device is triggered with alkaline solutions. Due to the rational design of the active VOx coating enabled by ALD, transience occurs through a rapid disabling step that occurs within seconds, followed by full dissolution of all active materials within 30 minutes of the initial trigger. This work demonstrates how engineered materials for energy storage can provide a basis for next-generation transient systems and highlights porous silicon as a versatile scaffold to integrate transient energy storage into transient electronics. Electronic supplementary information (ESI) available: (i) Experimental details for ALD and material fabrication, ellipsometry film thickness, preparation of gel electrolyte and separator, details for electrochemical measurements, HRTEM image of VOx coated porous silicon, Raman spectroscopy for VOx as-deposited as well as annealed in air for 1 hour at 450 °C, SEM and transient behavior dissolution tests of uniformly coated VOx on

SAR exposure from UHF RFID reader in adult, child, pregnant woman, and fetus anatomical models.

Science.gov (United States)

Fiocchi, Serena; Markakis, Ioannis A; Ravazzani, Paolo; Samaras, Theodoros

2013-09-01

The spread of radio frequency identification (RFID) devices in ubiquitous applications without their simultaneous exposure assessment could give rise to public concerns about their potential adverse health effects. Among the various RFID system categories, the ultra high frequency (UHF) RFID systems have recently started to be widely used in many applications. This study addresses a computational exposure assessment of the electromagnetic radiation generated by a realistic UHF RFID reader, quantifying the exposure levels in different exposure scenarios and subjects (two adults, four children, and two anatomical models of women 7 and 9 months pregnant). The results of the computations are presented in terms of the whole-body and peak spatial specific absorption rate (SAR) averaged over 10 g of tissue to allow comparison with the basic restrictions of the exposure guidelines. The SAR levels in the adults and children were below 0.02 and 0.8 W/kg in whole-body SAR and maximum peak SAR levels, respectively, for all tested positions of the antenna. On the contrary, exposure of pregnant women and fetuses resulted in maximum peak SAR(10 g) values close to the values suggested by the guidelines (2 W/kg) in some of the exposure scenarios with the antenna positioned in front of the abdomen and with a 100% duty cycle and 1 W radiated power. Copyright © 2013 Wiley Periodicals, Inc.

Integrated Circuit Interconnect Lines on Lossy Silicon Substrate with Finite Element Method

OpenAIRE

Sarhan M. Musa,; Matthew N. O. Sadiku

2014-01-01

The silicon substrate has a significant effect on the inductance parameter of a lossy interconnect line on integrated circuit. It is essential to take this into account in determining the transmission line electrical parameters. In this paper, a new quasi-TEM capacitance and inductance analysis of multiconductor multilayer interconnects is successfully demonstrated using finite element method (FEM). We specifically illustrate the electrostatic modeling of single and coupled in...

The Capacitive Magnetic Field Sensor

Science.gov (United States)

Zyatkov, D. O.; Yurchenko, A. V.; Balashov, V. B.; Yurchenko, V. I.

2016-01-01

The results of a study of sensitive element magnetic field sensor are represented in this paper. The sensor is based on the change of the capacitance with an active dielectric (ferrofluid) due to the magnitude of magnetic field. To prepare the ferrofluid magnetic particles are used, which have a followingdispersion equal to 50 brand 5BDSR. The dependence of the sensitivity of the capacitive element from the ferrofluid with different dispersion of magnetic particles is considered. The threshold of sensitivity and sensitivity of a measuring cell with ferrofluid by a magnetic field was determined. The experimental graphs of capacitance change of the magnitude of magnetic field are presented.

Virtual electrical capacitance tomography sensor

International Nuclear Information System (INIS)

Li, Y; Yang, W Q

2005-01-01

Electrical capacitance tomography (ECT) is an effective technique for elucidating the distribution of dielectric materials inside closed pipes or vessels. This paper describes a virtual electrical capacitance tomography (VECT) system, which can simulate a range of sensor and hardware configurations and material distributions. A selection of popular image reconstruction algorithms has been made available and image error and capacitance error tools enable their performance to be evaluated and compared. Series of frame-by-frame results can be stored for simulating real-time dynamic flows. The system is programmed in Matlab with DOS functions. It is convenient to use and low-cost to operate, providing an effective tool for engineering experiment

Flexible PVDF ferroelectric capacitive temperature sensor

KAUST Repository

Khan, Naveed

2015-08-02

In this paper, a capacitive temperature sensor based on polyvinylidene fluoride (PVDF) capacitor is explored. The PVDF capacitor is characterized below its Curie temperature. The capacitance of the PVDF capacitor changes vs temperature with a sensitivity of 16pF/°C. The linearity measurement of the capacitance-temperature relation shows less than 0.7°C error from a best fit straight line. An LC oscillator based temperature sensor is demonstrated based on this capacitor.

Fabrication of three-dimensional MIS nano-capacitor based on nano-imprinted single crystal silicon nanowire arrays

KAUST Repository

Zhai, Yujia

2012-11-26

We report fabrication of single crystalline silicon nanowire based-three-dimensional MIS nano-capacitors for potential analog and mixed signal applications. The array of nanowires is patterned by Step and Flash Imprint Lithography (S-FIL). Deep silicon etching (DSE) is used to form the nanowires with high aspect ratio, increase the electrode area and thus significantly enhance the capacitance. High-! dielectric is deposited by highly conformal atomic layer deposition (ALD) Al2O3 over the Si nanowires, and sputtered metal TaN serves as the electrode. Electrical measurements of fabricated capacitors show the expected increase of capacitance with greater nanowire height and decreasing dielectric thickness, consistent with calculations. Leakage current and time-dependent dielectric breakdown (TDDB) are also measured and compared with planar MIS capacitors. In view of greater interest in 3D transistor architectures, such as FinFETs, 3D high density MIS capacitors offer an attractive device technology for analog and mixed signal applications. - See more at: http://www.eurekaselect.com/105099/article#sthash.EzeJxk6j.dpuf

Fabrication of three-dimensional MIS nano-capacitor based on nano-imprinted single crystal silicon nanowire arrays

KAUST Repository

Zhai, Yujia; Palard, Marylene; Mathew, Leo; Hussain, Muhammad Mustafa; Willson, Grant Grant; Tutuc, Emanuel; Banerjee, Sanjay Kumar

2012-01-01

We report fabrication of single crystalline silicon nanowire based-three-dimensional MIS nano-capacitors for potential analog and mixed signal applications. The array of nanowires is patterned by Step and Flash Imprint Lithography (S-FIL). Deep silicon etching (DSE) is used to form the nanowires with high aspect ratio, increase the electrode area and thus significantly enhance the capacitance. High-! dielectric is deposited by highly conformal atomic layer deposition (ALD) Al2O3 over the Si nanowires, and sputtered metal TaN serves as the electrode. Electrical measurements of fabricated capacitors show the expected increase of capacitance with greater nanowire height and decreasing dielectric thickness, consistent with calculations. Leakage current and time-dependent dielectric breakdown (TDDB) are also measured and compared with planar MIS capacitors. In view of greater interest in 3D transistor architectures, such as FinFETs, 3D high density MIS capacitors offer an attractive device technology for analog and mixed signal applications. - See more at: http://www.eurekaselect.com/105099/article#sthash.EzeJxk6j.dpuf

Optoelectronic properties of Black-Silicon generated through inductively coupled plasma (ICP) processing for crystalline silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

Hirsch, Jens, E-mail: J.Hirsch@emw.hs-anhalt.de [Anhalt University of Applied Sciences, Faculty EMW, Bernburger Str. 55, DE-06366 Köthen (Germany); Fraunhofer Center for Silicon Photovoltaics CSP, Otto-Eißfeldt-Str. 12, DE-06120 Halle (Saale) (Germany); Gaudig, Maria; Bernhard, Norbert [Anhalt University of Applied Sciences, Faculty EMW, Bernburger Str. 55, DE-06366 Köthen (Germany); Lausch, Dominik [Fraunhofer Center for Silicon Photovoltaics CSP, Otto-Eißfeldt-Str. 12, DE-06120 Halle (Saale) (Germany)

2016-06-30

Highlights: • Fabrication of black silicon through inductively coupled plasma (ICP) processing. • Suppressed formation a self-bias and therefore a reduced ion bombardment of the silicon sample. • Reduction of the average hemispherical reflection between 300 and 1120 nm up to 8% within 5 min ICP process time. • Reflection is almost independent of the angle of incidence up to 60°. • 2.5 ms effective lifetime at 10{sup 15} cm{sup −3} MCD after ALD Al{sub 2}O{sub 3} surface passivation. - Abstract: The optoelectronic properties of maskless inductively coupled plasma (ICP) generated black silicon through SF{sub 6} and O{sub 2} are analyzed by using reflection measurements, scanning electron microscopy (SEM) and quasi steady state photoconductivity (QSSPC). The results are discussed and compared to capacitively coupled plasma (CCP) and industrial standard wet chemical textures. The ICP process forms parabolic like surface structures in a scale of 500 nm. This surface structure reduces the average hemispherical reflection between 300 and 1120 nm up to 8%. Additionally, the ICP texture shows a weak increase of the hemispherical reflection under tilted angles of incidence up to 60°. Furthermore, we report that the ICP process is independent of the crystal orientation and the surface roughness. This allows the texturing of monocrystalline, multicrystalline and kerf-less wafers using the same parameter set. The ICP generation of black silicon does not apply a self-bias on the silicon sample. Therefore, the silicon sample is exposed to a reduced ion bombardment, which reduces the plasma induced surface damage. This leads to an enhancement of the effective charge carrier lifetime up to 2.5 ms at 10{sup 15} cm{sup −3} minority carrier density (MCD) after an atomic layer deposition (ALD) with Al{sub 2}O{sub 3}. Since excellent etch results were obtained already after 4 min process time, we conclude that the ICP generation of black silicon is a promising technique

Inverse modeling applied to Scanning Capacitance Microscopy for improved spatial resolution and accuracy

International Nuclear Information System (INIS)

McMurray, J. S.; Williams, C. C.

1998-01-01

Scanning Capacitance Microscopy (SCM) is capable of providing two-dimensional information about dopant and carrier concentrations in semiconducting devices. This information can be used to calibrate models used in the simulation of these devices prior to manufacturing and to develop and optimize the manufacturing processes. To provide information for future generations of devices, ultra-high spatial accuracy (<10 nm) will be required. One method, which potentially provides a means to obtain these goals, is inverse modeling of SCM data. Current semiconducting devices have large dopant gradients. As a consequence, the capacitance probe signal represents an average over the local dopant gradient. Conversion of the SCM signal to dopant density has previously been accomplished with a physical model which assumes that no dopant gradient exists in the sampling area of the tip. The conversion of data using this model produces results for abrupt profiles which do not have adequate resolution and accuracy. A new inverse model and iterative method has been developed to obtain higher resolution and accuracy from the same SCM data. This model has been used to simulate the capacitance signal obtained from one and two-dimensional ideal abrupt profiles. This simulated data has been input to a new iterative conversion algorithm, which has recovered the original profiles in both one and two dimensions. In addition, it is found that the shape of the tip can significantly impact resolution. Currently SCM tips are found to degrade very rapidly. Initially the apex of the tip is approximately hemispherical, but quickly becomes flat. This flat region often has a radius of about the original hemispherical radius. This change in geometry causes the silicon directly under the disk to be sampled with approximately equal weight. In contrast, a hemispherical geometry samples most strongly the silicon centered under the SCM tip and falls off quickly with distance from the tip's apex. Simulation

Microscopic study of electrical properties of CrSi2 nanocrystals in silicon

Directory of Open Access Journals (Sweden)

Lányi Štefan

2011-01-01

Full Text Available Abstract Semiconducting CrSi2 nanocrystallites (NCs were grown by reactive deposition epitaxy of Cr onto n-type silicon and covered with a 50-nm epitaxial silicon cap. Two types of samples were investigated: in one of them, the NCs were localized near the deposition depth, and in the other they migrated near the surface. The electrical characteristics were investigated in Schottky junctions by current-voltage and capacitance-voltage measurements. Atomic force microscopy (AFM, conductive AFM and scanning probe capacitance microscopy (SCM were applied to reveal morphology and local electrical properties. The scanning probe methods yielded specific information, and tapping-mode AFM has shown up to 13-nm-high large-area protrusions not seen in the contact-mode AFM. The electrical interaction of the vibrating scanning tip results in virtual deformation of the surface. SCM has revealed NCs deep below the surface not seen by AFM. The electrically active probe yielded significantly better spatial resolution than AFM. The conductive AFM measurements have shown that the Cr-related point defects near the surface are responsible for the leakage of the macroscopic Schottky junctions, and also that NCs near the surface are sensitive to the mechanical and electrical stress induced by the scanning probe.

Low-cost low-power UHF RFID tag with on-chip antenna

Energy Technology Data Exchange (ETDEWEB)

Xi Jingtian; Yan Na; Che Wenyi; Xu Conghui; Wang Xiao; Yang Yuqing; Jian Hongyan; Min Hao, E-mail: jtxi@fudan.edu.c [State Key Laboratory of ASIC and System, Auto-ID Laboratory, Fudan University, Shanghai 201203 (China)

2009-07-15

This paper presents an EPC Class 1 Generation 2 compatible tag with on-chip antenna implemented in the SMIC 0.18 {mu}m standard CMOS process. The UHF tag chip includes an RF/analog front-end, a digital baseband, and a 640-bit EEPROM memory. The on-chip antenna is optimized based on a novel parasitic-aware model. The rectifier is optimized to achieve a power conversion efficiency up to 40% by applying a self-bias feedback and threshold compensation techniques. A good match between the tag circuits and the on-chip antenna is realized by adjusting the rectifier input impedance. Measurements show that the presented tag can achieve a communication range of 1 cm with 1 W reader output power using a 1 x 1 cm{sup 2} single-turn loop reader antenna.

A passive UHF RFID tag with a dynamic-Vth-cancellation rectifier

International Nuclear Information System (INIS)

Shen Jinpeng; Wang Bo; Liu Shan; Wang Xin'an; Ruan Zhengkun; Li Shoucheng

2013-01-01

This paper presents a passive UHF RFID tag with a dynamic-V th -cancellation (DVC) rectifier. In the rectifier, the threshold voltages of MOSFETs are cancelled by applying gate bias voltages, which are dynamically changed according to the states of the MOSFETs. The DVC rectifier enables both low ON-resistance and small reverse leakage of the MOSFETs, resulting in high power conversion efficiency (PCE). An area-efficient demodulator with a novel average detector is also designed, which takes advantage of the rectifier's first stage as the envelope detector. The whole tag chip is implemented in a 0.18 μm CMOS process with a die size of 880 × 950 μm 2 . Measurement results show that the rectifier achieves a maximum PCE of 53.7% with 80 kΩ resistor load. (semiconductor integrated circuits)

Wide-Range Adaptive RF-to-DC Power Converter for UHF RFIDs

KAUST Repository

Ouda, Mahmoud H.

2016-07-27

A wide-range, differential, cross-coupled rectifier is proposed with an extended dynamic range of input RF power that enables wireless powering from varying distances. The proposed architecture mitigates the reverse-leakage problem in conven- tional, cross-coupled rectifiers without degrading sensitivity. A prototype is designed for UHF RFID applications, and is imple- mented using 0.18 μ m CMOS technology. On-chip measurements demonstrate a sensitivity of − 18 dBm for 1 V output over a 100 k Ω load and a peak RF-to-DC power conversion efficiency of 65%. A conventional, fully cross-coupled rectifier is fabricated along- side for comparison and the proposed rectifier shows more than 2 × increase in dynamic range and a 25% boosting in output voltage than the conventional rectifier

Meteor head echo polarization at 930 MHz studied with the EISCAT UHF HPLA radar

Directory of Open Access Journals (Sweden)

G. Wannberg

2011-06-01

Full Text Available The polarization characteristics of 930-MHz meteor head echoes have been studied for the first time, using data obtained in a series of radar measurements carried out with the tristatic EISCAT UHF high power, large aperture (HPLA radar system in October 2009. An analysis of 44 tri-static head echo events shows that the polarization of the echo signal recorded by the Kiruna receiver often fluctuates strongly on time scales of tens of microseconds, illustrating that the scattering process is essentially stochastic. On longer timescales (> milliseconds, more than 90 % of the recorded events show an average polarization signature that is independent of meteor direction of arrival and echo strength and equal to that of an incoherent-scatter return from underdense plasma filling the tristatic observation volume. This shows that the head echo plasma targets scatter isotropically, which in turn implies that they are much smaller than the 33-cm wavelength and close to spherically symmetric, in very good agreement with results from a previous EISCAT UHF study of the head echo RCS/meteor angle-of-incidence relationship. Significant polarization is present in only three events with unique target trajectories. These all show a larger effective target cross section transverse to the trajectory than parallel to it. We propose that the observed polarization may be a signature of a transverse charge separation plasma resonance in the region immediately behind the meteor head, similar to the resonance effects previously discussed in connection with meteor trail echoes by Herlofson, Billam and Browne, Jones and Jones and others.

A bipolar monolithic preamplifier for high-capacitance SSC [Superconducting Super Collider] silicon calorimetry

International Nuclear Information System (INIS)

Britton, C.L. Jr.; Kennedy, E.J.; Bugg, W.M.

1990-01-01

This paper describes a preamplifier designed and fabricated specifically to address the requirements of silicon calorimetry for the Superconducting Super Collider (SSC). The topology and its features are discussed in addition to the design methodology employed. The simulated and measured results for noise, power consumption, and speed are presented. Simulated an measured data for radiation damage effects as well as data for post-damage annealing are also presented. 8 refs., 7 figs., 2 tabs

Calculation of secondary capacitance of compact Tesla pulse transformer

International Nuclear Information System (INIS)

Yu Binxiong; Liu Jinliang

2013-01-01

An analytic expression of the secondary capacitance of a compact Tesla pulse transformer is derived. Calculated result by the expression shows that two parts contribute to the secondary capacitance, namely the capacitance between inner and outer magnetic cores and the attached capacitance caused by the secondary winding. The attached capacitance equals to the capacitance of a coaxial line which is as long as the secondary coil, and whose outer and inner diameters are as large as the inner diameter of the outer magnetic and the outer diameter of the inner magnetic core respectively. A circuital model for analyzing compact Tesla transformer is built, and numeric calculation shows that the expression of the secondary capacitance is correct. Besides, a small compact Tesla transformer is developed, and related test is carried out. Test result confirms the calculated results by the expression derived. (authors)

Quantum capacitance of the armchair-edge graphene nanoribbon

Indian Academy of Sciences (India)

Home; Journals; Pramana – Journal of Physics; Volume 81; Issue 2. Quantum capacitance of the ... Abstract. The quantum capacitance, an important parameter in the design of nanoscale devices, is derived for armchair-edge single-layer graphene nanoribbon with semiconducting property. The quantum capacitance ...

Methods of optimising ion beam induced charge collection of polycrystalline silicon photovoltaic cells

International Nuclear Information System (INIS)

Witham, L.C.G.; Jamieson, D.N.; Bardos, R.A.

1998-01-01

Ion Beam Induced Charge (IBIC) is a valuable method for the mapping of charge carrier transport and recombination in silicon solar cells. However performing IBIC analysis of polycrystalline silicon solar cells is problematic in a manner unlike previous uses of IBIC on silicon-based electronic devices. Typical solar cells have a surface area of several square centimeters and a p-n junction thickness of only few microns. This means the cell has a large junction capacitance in the many nanoFarads range which leads to a large amount of noise on the preamplifier inputs which typically swamps the transient IBIC signal. The normal method of improving the signal-to-noise (S/N) ratio by biasing the junction is impractical for these cells as the low-quality silicon used leads to a large leakage current across the device. We present several experimental techniques which improve the S/N ratio which when used together should make IBIC analysis of many low crystalline quality devices a viable and reliable procedure. (authors)

Investigation of particle reduction and its transport mechanism in UHF-ECR dielectric etching system

International Nuclear Information System (INIS)

Kobayashi, Hiroyuki; Yokogawa, Ken'etsu; Maeda, Kenji; Izawa, Masaru

2008-01-01

Control of particle transport was investigated by using a UHF-ECR etching apparatus with a laser particle monitor. The particles, which float at a plasma-sheath boundary, fall on a wafer when the plasma is turned off. These floating particles can be removed from the region above the wafer by changing the plasma distribution. We measured the distribution of the rotational temperature of nitrogen molecules across the wafer to investigate the effect of the thermophoretic force. We found that mechanisms of particle transport in directions parallel to the wafer surface can be explained by the balance between thermophoretic and gas viscous forces

Towards Washable Electrotextile UHF RFID Tags: Reliability Study of Epoxy-Coated Copper Fabric Antennas

Directory of Open Access Journals (Sweden)

Shiqi Wang

2015-01-01

Full Text Available We investigate the impact of washing on the performance of passive UHF RFID tags based on dipole antennas fabricated from copper fabric and coated with protective epoxy coating. Initially, the tags achieved read ranges of about 8 meters, under the European RFID emission regulation. To assess the impact of washing on the performance of the tags, they were washed repeatedly in a washing machine and measured after every washing cycle. Despite the reliability challenges related to mechanical stress, the used epoxy coating was found to be a promising coating for electrotextile tags in moist conditions.

Scenarios and business models for mobile network operators utilizing the hybrid use concept of the UHF broadcasting spectrum

Directory of Open Access Journals (Sweden)

S. Yrjölä

2016-09-01

Full Text Available This paper explores and presents scenarios and business models for mobile network operators (MNOs in the novel hybrid use spectrum sharing concept of the Ultra High Frequency broadcasting spectrum (470-790 MHz used for Digital Terrestrial TV (DTT and Mobile Broadband (MBB. More flexible use of the band could lead to higher efficiency in delivering fast growing and converging MBB, media and TV content to meet changing consumer needs. On one hand, this could be beneficial for broadcasters (BC, e.g., by preserving the spectrum, by providing additional revenues, or by lowering cost of the spectrum and, on the other hand, for MNOs to gain faster access to new potentially lower cost, licensed, below 1GHz spectrum to cope with booming data traffic. As a collaborative benefit, the concept opens up new business opportunities for delivering TV and media content using MBB network with means to introduce this flexibly. This paper highlights the importance of developing sound business models for the new spectrum use concept, as they need to provide clear benefits to the key stakeholders to be adopted in real life. The paper applies a future and action oriented approach to the MBB using the concept to derive scenarios and business models for MNOs for accessing hybrid UHF bands. In order to address the convergence and transformation coming with the concept, business models are first developed for the current situation with separate exclusive spectrum bands. Novel business scenarios are then developed for the introduction of the new flexible hybrid UHF spectrum concept. The created business model indicates that the MNOs could benefit significantly from the new UHF bands, which would enable them to cope with increasing data traffic asymmetry, and to offer differentiation through personalized broadcasting and new media services. Moreover, it could significantly re-shape the business ecosystem around both the broadcasting and the mobile broadband by introducing

Origin of dislocation luminescence centers and their reorganization in p-type silicon crystal subjected to plastic deformation and high temperature annealing.

Science.gov (United States)

Pavlyk, Bohdan; Kushlyk, Markiyan; Slobodzyan, Dmytro

2017-12-01

Changes of the defect structure of silicon p-type crystal surface layer under the influence of plastic deformation and high temperature annealing in oxygen atmosphere were investigated by deep-level capacitance-modulation spectroscopy (DLCMS) and IR spectroscopy of molecules and atom vibrational levels. Special role of dislocations in the surface layer of silicon during the formation of its energy spectrum and rebuilding the defective structure was established. It is shown that the concentration of linear defects (N ≥ 10 4  cm -2 ) enriches surface layer with electrically active complexes (dislocation-oxygen, dislocation-vacancy, and dislocation-interstitial atoms of silicon) which are an effective radiative recombination centers.

Characterization of silicon-on-insulator wafers

Science.gov (United States)

Park, Ki Hoon

The silicon-on-insulator (SOI) is attracting more interest as it is being used for an advanced complementary-metal-oxide-semiconductor (CMOS) and a base substrate for novel devices to overcome present obstacles in bulk Si scaling. Furthermore, SOI fabrication technology has improved greatly in recent years and industries produce high quality wafers with high yield. This dissertation investigated SOI material properties with simple, yet accurate methods. The electrical properties of as-grown wafers such as electron and hole mobilities, buried oxide (BOX) charges, interface trap densities, and carrier lifetimes were mainly studied. For this, various electrical measurement techniques were utilized such as pseudo-metal-oxide-semiconductor field-effect-transistor (PseudoMOSFET) static current-voltage (I-V) and transient drain current (I-t), Hall effect, and MOS capacitance-voltage/capacitance-time (C-V/C-t). The electrical characterization, however, mainly depends on the pseudo-MOSFET method, which takes advantage of the intrinsic SOI structure. From the static current-voltage and pulsed measurement, carrier mobilities, lifetimes and interface trap densities were extracted. During the course of this study, a pseudo-MOSFET drain current hysteresis regarding different gate voltage sweeping directions was discovered and the cause was revealed through systematic experiments and simulations. In addition to characterization of normal SOI, strain relaxation of strained silicon-on-insulator (sSOI) was also measured. As sSOI takes advantage of wafer bonding in its fabrication process, the tenacity of bonding between the sSOI and the BOX layer was investigated by means of thermal treatment and high dose energetic gamma-ray irradiation. It was found that the strain did not relax with processes more severe than standard CMOS processes, such as anneals at temperature as high as 1350 degree Celsius.

Resistive and Capacitive Based Sensing Technologies

Directory of Open Access Journals (Sweden)

Winncy Y. Du

2008-04-01

Full Text Available Resistive and capacitive (RC sensors are the most commonly used sensors. Their applications span homeland security, industry, environment, space, traffic control, home automation, aviation, and medicine. More than 30% of modern sensors are direct or indirect applications of the RC sensing principles. This paper reviews resistive and capacitive sensing technologies. The physical principles of resistive sensors are governed by several important laws and phenomena such as Ohm’s Law, Wiedemann-Franz Law; Photoconductive-, Piezoresistive-, and Thermoresistive Effects. The applications of these principles are presented through a variety of examples including accelerometers, flame detectors, pressure/flow rate sensors, RTDs, hygristors, chemiresistors, and bio-impedance sensors. The capacitive sensors are described through their three configurations: parallel (flat, cylindrical (coaxial, and spherical (concentric. Each configuration is discussed with respect to its geometric structure, function, and application in various sensor designs. Capacitance sensor arrays are also presented in the paper.

Capacitance of carbon-based electrical double-layer capacitors.

Science.gov (United States)

Ji, Hengxing; Zhao, Xin; Qiao, Zhenhua; Jung, Jeil; Zhu, Yanwu; Lu, Yalin; Zhang, Li Li; MacDonald, Allan H; Ruoff, Rodney S

2014-01-01

Experimental electrical double-layer capacitances of porous carbon electrodes fall below ideal values, thus limiting the practical energy densities of carbon-based electrical double-layer capacitors. Here we investigate the origin of this behaviour by measuring the electrical double-layer capacitance in one to five-layer graphene. We find that the capacitances are suppressed near neutrality, and are anomalously enhanced for thicknesses below a few layers. We attribute the first effect to quantum capacitance effects near the point of zero charge, and the second to correlations between electrons in the graphene sheet and ions in the electrolyte. The large capacitance values imply gravimetric energy storage densities in the single-layer graphene limit that are comparable to those of batteries. We anticipate that these results shed light on developing new theoretical models in understanding the electrical double-layer capacitance of carbon electrodes, and on opening up new strategies for improving the energy density of carbon-based capacitors.

Investigating Feasibility Of Multiple UHF Passive RFID Transmitters Using Backscatter Modulation Scheme In BCI Applications

DEFF Research Database (Denmark)

Al Ajrawi, Shams; Sarkar, Mahasweta; Rao, Ramesh

simulatedbrain matter to a receiver located on the surface of a simulatedskull. These analyses are essential for building a brain computerinterface application. We showcase theoretical and experimentalresults based on a phantom model of the human brain usingpassive RFID as the implantable transmitter operating...... in UHFrange. Furthermore, we use backscatter modulation as a powertransfer mechanism. Investigation on the feasibility and appli-cability of implantable UHF Passive RFID transmitters insidethe brain is done for capturing multi-channel ECoG signals at ahigh data transfer rate. Detailed analysis have been done...

Novel RF-MEMS capacitive switching structures

NARCIS (Netherlands)

Rottenberg, X.; Jansen, Henricus V.; Fiorini, P.; De Raedt, W.; Tilmans, H.A.C.

2002-01-01

This paper reports on novel RF-MEMS capacitive switching devices implementing an electrically floating metal layer covering the dielectric to ensure intimate contact with the bridge in the down state. This results in an optimal switch down capacitance and allows optimisation of the down/up

The Pyramidal Capacitated Vehicle Routing Problem

DEFF Research Database (Denmark)

Lysgaard, Jens

This paper introduces the Pyramidal Capacitated Vehicle Routing Problem (PCVRP) as a restricted version of the Capacitated Vehicle Routing Problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the Pyramidal Traveling Salesman Problem (PTSP). A pyramidal...

The pyramidal capacitated vehicle routing problem

DEFF Research Database (Denmark)

Lysgaard, Jens

2010-01-01

This paper introduces the pyramidal capacitated vehicle routing problem (PCVRP) as a restricted version of the capacitated vehicle routing problem (CVRP). In the PCVRP each route is required to be pyramidal in a sense generalized from the pyramidal traveling salesman problem (PTSP). A pyramidal...

The silicon vertex detector of the Belle II experiment

Energy Technology Data Exchange (ETDEWEB)

Adamczyk, K. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Aihara, H. [Department of Physics, University of Tokyo, Tokyo 113-0033 (Japan); Angelini, C. [Dipartimento di Fisica, Universitá di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Aziz, T.; Babu, V. [Tata Institute of Fundamental Research, Mumbai 400005 (India); Bacher, S. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); Bahinipati, S. [Indian Institute of Technology Bhubaneswar, Satya Nagar (India); Barberio, E.; Baroncelli, T. [School of Physics, University of Melbourne, Melbourne, Victoria 3010 (Australia); Basith, A.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Batignani, G. [Dipartimento di Fisica, Universitá di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bauer, A. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Behera, P.K. [Indian Institute of Technology Madras, Chennai 600036 (India); Bergauer, T. [Institute of High Energy Physics, Austrian Academy of Sciences, 1050 Vienna (Austria); Bettarini, S. [Dipartimento di Fisica, Universitá di Pisa, I-56127 Pisa (Italy); INFN Sezione di Pisa, I-56127 Pisa (Italy); Bhuyan, B. [Indian Institute of Technology Guwahati, Assam 781039 (India); Bilka, T. [Faculty of Mathematics and Physics, Charles University, 121 16 Prague (Czech Republic); Bosi, F. [INFN Sezione di Pisa, I-56127 Pisa (Italy); Bosisio, L. [Dipartimento di Fisica, Universitá di Trieste, I-34127 Trieste (Italy); INFN Sezione di Trieste, I-34127 Trieste (Italy); Bozek, A. [H. Niewodniczanski Institute of Nuclear Physics, Krakow 31-342 (Poland); and others

2016-07-11

The silicon vertex detector of the Belle II experiment, structured in a lantern shape, consists of four layers of ladders, fabricated from two to five silicon sensors. The APV25 readout ASIC chips are mounted on one side of the ladder to minimize the signal path for reducing the capacitive noise; signals from the sensor backside are transmitted to the chip by bent flexible fan-out circuits. The ladder is assembled using several dedicated jigs. Sensor motion on the jig is minimized by vacuum chucking. The gluing procedure provides such a rigid foundation that later leads to the desired wire bonding performance. The full ladder with electrically functional sensors is consistently completed with a fully developed assembly procedure, and its sensor offsets from the design values are found to be less than 200 μm. The potential functionality of the ladder is also demonstrated by the radioactive source test.

Scanning Capacitance Microscopy | Materials Science | NREL

Science.gov (United States)

obtained using scanning capacitance microscopy. Top Right: Image of p-type and n-type material, obtained 'fingers' of light-colored n-type material on a yellow and blue background representing p-type material material, obtained using scanning capacitance microscopy, in a sample semiconductor device; the image shows

Design Considerations in Capacitively Coupled Plasmas

Science.gov (United States)

Song, Sang-Heon; Ventzek, Peter; Ranjan, Alok

2015-11-01

Microelectronics industry has driven transistor feature size scaling from 10-6 m to 10-9 m during the past 50 years, which is often referred to as Moore's law. It cannot be overstated that today's information technology would not have been so successful without plasma material processing. One of the major plasma sources for the microelectronics fabrication is capacitively coupled plasmas (CCPs). The CCP reactor has been intensively studied and developed for the deposition and etching of different films on the silicon wafer. As the feature size gets to around 10 nm, the requirement for the process uniformity is less than 1-2 nm across the wafer (300 mm). In order to achieve the desired uniformity, the hardware design should be as precise as possible before the fine tuning of process condition is applied to make it even better. In doing this procedure, the computer simulation can save a significant amount of resources such as time and money which are critical in the semiconductor business. In this presentation, we compare plasma properties using a 2-dimensional plasma hydrodynamics model for different kinds of design factors that can affect the plasma uniformity. The parameters studied in this presentation include chamber accessing port, pumping port, focus ring around wafer substrate, and the geometry of electrodes of CCP.

Low dose radiation damage effects in silicon strip detectors

International Nuclear Information System (INIS)

Wiącek, P.; Dąbrowski, W.

2016-01-01

The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

Low dose radiation damage effects in silicon strip detectors

Science.gov (United States)

Wiącek, P.; Dąbrowski, W.

2016-11-01

The radiation damage effects in silicon segmented detectors caused by X-rays have become recently an important research topic driven mainly by development of new detectors for applications at the European X-ray Free Electron Laser (E-XFEL). However, radiation damage in silicon strip is observed not only after extreme doses up to 1 GGy expected at E-XFEL, but also at doses in the range of tens of Gy, to which the detectors in laboratory instruments like X-ray diffractometers or X-ray spectrometers can be exposed. In this paper we report on investigation of radiation damage effects in a custom developed silicon strip detector used in laboratory diffractometers equipped with X-ray tubes. Our results show that significant degradation of detector performance occurs at low doses, well below 200 Gy, which can be reached during normal operation of laboratory instruments. Degradation of the detector energy resolution can be explained by increasing leakage current and increasing interstrip capacitance of the sensor. Another observed effect caused by accumulation of charge trapped in the surface oxide layer is change of charge division between adjacent strips. In addition, we have observed unexpected anomalies in the annealing process.

Capacitance densitometer for flow regime identification

International Nuclear Information System (INIS)

Shipp, R.L. Jr.

1978-01-01

This invention relates to a capacitance densitometer for determining the flow regime of a two-phase flow system. A two-element capacitance densitometer is used in conjunction with a conventional single-beam gamma densitometer to unambiguously identify the prevailing flow regime and the average density of a flowing fluid

Charge separation technique for metal-oxide-silicon capacitors in the presence of hydrogen deactivated dopants

International Nuclear Information System (INIS)

Witczak, Steven C.; Winokur, Peter S.; Lacoe, Ronald C.; Mayer, Donald C.

2000-01-01

An improved charge separation technique for metal-oxide-silicon (MOS) capacitors is presented which accounts for the deactivation of substrate dopants by hydrogen at elevated irradiation temperatures or small irradiation biases. Using high-frequency capacitance-voltage (C-V) measurements, radiation-induced inversion voltage shifts are separated into components due to oxide trapped charge, interface traps and deactivated dopants, where the latter is computed from a reduction in Si capacitance. In the limit of no radiation-induced dopant deactivation, this approach reduces to the standard midgap charge separation technique used widely for the analysis of room-temperature irradiations. The technique is demonstrated on a p-type MOS capacitor irradiated with 60 Co γ-rays at 100 C and zero bias, where the dopant deactivation is significant

Extended post processing for simulation results of FEM synthesized UHF-RFID transponder antennas

Directory of Open Access Journals (Sweden)

R. Herschmann

2007-06-01

Full Text Available The computer aided design process of sophisticated UHF-RFID transponder antennas requires the application of reliable simulation software. This paper describes a Matlab implemented extension of the post processor capabilities of the commercially available three dimensional field simulation programme Ansoft HFSS to compute an accurate solution of the antenna's surface current distribution. The accuracy of the simulated surface currents, which are physically related to the impedance at the feeding point of the antenna, depends on the convergence of the electromagnetic fields inside the simulation volume. The introduced method estimates the overall quality of the simulation results by combining the surface currents with the electromagnetic fields extracted from the field solution of Ansoft HFSS.

Development of two U.H.F. band resonators for application to CO2 laser electro-optical modulation

International Nuclear Information System (INIS)

Egan, M.G.; Blanc, P.; Sexton, M.C.

1980-01-01

The purpose of this report is to describe the design and testing of two U.H.F. band resonators destined for use in the linear electro-optical modulator of the CO 2 Laser Rapid Interferometer diagnostic at present under development for the WEGA Tokamak. The resonators take the form of a re-entrant coaxial line cavity and an interdigital line filter, both of which possess the regions of high electric field necessary to activate the linear electro-optical effect

Voltage Dependence of Supercapacitor Capacitance

Directory of Open Access Journals (Sweden)

Szewczyk Arkadiusz

2016-09-01

Full Text Available Electronic Double-Layer Capacitors (EDLC, called Supercapacitors (SC, are electronic devices that are capable to store a relatively high amount of energy in a small volume comparing to other types of capacitors. They are composed of an activated carbon layer and electrolyte solution. The charge is stored on electrodes, forming the Helmholtz layer, and in electrolyte. The capacitance of supercapacitor is voltage- dependent. We propose an experimental method, based on monitoring of charging and discharging a supercapacitor, which enables to evaluate the charge in an SC structure as well as the Capacitance-Voltage (C-V dependence. The measurement setup, method and experimental results of charging/discharging commercially available supercapacitors in various voltage and current conditions are presented. The total charge stored in an SC structure is proportional to the square of voltage at SC electrodes while the charge on electrodes increases linearly with the voltage on SC electrodes. The Helmholtz capacitance increases linearly with the voltage bias while a sublinear increase of total capacitance was found. The voltage on SC increases after the discharge of electrodes due to diffusion of charges from the electrolyte to the electrodes. We have found that the recovery voltage value is linearly proportional to the initial bias voltage value.

A low-voltage silicon condenser microphone for hearing instrument applications

DEFF Research Database (Denmark)

Rombach, Pirmin; Müllenborn, Matthias; Klein, Udo

1999-01-01

the input-related noise of the following preamplifier stage becomes dominant and results in a high equivalent input-related noise. Here a silicon condenser microphone with the potential for hearing instrument applications will be presented. To get the best properties for the different mechanical parts, e...... related A-weighted noise is 23 dB SPL, including the preamplifier. Due to a conservative layout, the parasitic capacitance is about 50%. An increase of 2–3 mV/Pa sensitivity and hence 3 dB SPL less noise can therefore be achieved by design optimization....

An improved detector response simulation for the CBM silicon tracking system

Energy Technology Data Exchange (ETDEWEB)

Malygina, Hanna [Goethe University, Frankfurt (Germany); Friese, Volker [GSI, Darmstadt (Germany); Collaboration: CBM-Collaboration

2015-07-01

The Compressed Baryonic Matter experiment(CBM) at FAIR is designed to explore the QCD phase diagram in the region of high net-baryon densities. The central detector component the Silicon Tracking System (STS) is build from double-sided micro-strip sensors. To achieve realistic simulations the response of the silicon strip sensors should be precisely included in the digitizer which simulates a complete chain of physical processes caused by charged particles traversing the detector, from charge creation in silicon to a digital output signal. The new version of the STS digitizer comprises in addition non-uniform energy loss distributions (according to the Urban theory), thermal diffusion and charge redistribution over the read-out channels due to interstrip capacitances. The improved response simulation was tested with parameters reproducing the anticipated running conditions of the CBM experiment. Two different method for cluster finding were used. The results for hit position residuals, cluster size distribution, as well as for some other parameters of reconstruction quality are presented. The achieved advance is assessed by a comparison with the previous, simpler version of the STS detector response simulation.

Two dimensional dopant diffusion study by scanning capacitance microscopy and TSUPREM IV process simulation

International Nuclear Information System (INIS)

Kim, J.; McMurray, J. S.; Williams, C. C.; Slinkman, J.

1998-01-01

We report the results of a 2-step two-dimensional (2D) diffusion study by Scanning Capacitance Microscopy (SCM) and 2D TSUPREM IV process simulation. A quantitative 2D dopant profile of gate-like structures consisting heavily implanted n+ regions separated by a lighter doped n-type region underneath 0.56 μm gates is measured with the SCM. The SCM is operated in the constant-change-in-capacitance mode. The 2-D SCM data is converted to dopant density through a physical model of the SCM/silicon interaction. This profile has been directly compared with 2D TSUPREM IV process simulation and used to calibrate the simulation parameters. The sample is then further subjected to an additional diffusion in a furnace for 80 minutes at 1000C. The SCM measurement is repeated on the diffused sample. This final 2D dopant profile is compared with a TSUPREM IV process simulation tuned to fit the earlier profile with no change in the parameters except the temperature and time for the additional diffusion. Our results indicate that there is still a significant disagreement between the two profiles in the lateral direction. TSUPREM IV simulation considerably underestimates the diffusion under the gate region

Ferroelectric Negative Capacitance Domain Dynamics

OpenAIRE

Hoffmann, Michael; Khan, Asif Islam; Serrao, Claudy; Lu, Zhongyuan; Salahuddin, Sayeef; Pešić, Milan; Slesazeck, Stefan; Schroeder, Uwe; Mikolajick, Thomas

2017-01-01

Transient negative capacitance effects in epitaxial ferroelectric Pb(Zr$_{0.2}$Ti$_{0.8}$)O$_3$ capacitors are investigated with a focus on the dynamical switching behavior governed by domain nucleation and growth. Voltage pulses are applied to a series connection of the ferroelectric capacitor and a resistor to directly measure the ferroelectric negative capacitance during switching. A time-dependent Ginzburg-Landau approach is used to investigate the underlying domain dynamics. The transien...

Capacitive divider for output voltage measurement of intense electron beam accelerator

International Nuclear Information System (INIS)

Ding Desheng; Yi Lingzhi; Yu Binxiong; Hong Zhiqiang; Liu Jinliang

2012-01-01

A kind of simple-mechanism, easy-disassembly self-integrating capacitive divider used for measuring diode output voltage of intense electron beam accelerator (IEBA) is developed. The structure of the capacitive divider is described, and the capacitance value of the capacitive divider is calculated by theoretical analysis and electromagnetic simulation. The dependence of measurement voltage on electrical parameters such as stray capacitance, earth capacitance of front resistance is obtained by PSpice simulation. Measured waveforms appear overshoot phenomenon when stray capacitance of front resistance is larger, and the wavefront will be affected when earth capacitance of front resistance is larger. The diode output voltage waveforms of intense electron beam accelerator, are measured by capacitive divider and calibrated by water resistance divider, which is accordance with that measured by a resistive divider, the division ratio is about 563007. The designed capacitive divider can be used to measure high-voltage pulse with 100 ns full width at half maximum. (authors)

Packaged Capacitive Pressure Sensor System for Aircraft Engine Health Monitoring

Science.gov (United States)

Scardelletti, Maximilian C.; Zorman, Christian A.

2016-01-01

This paper describes the development of a packaged silicon carbide (SiC) based MEMS pressure sensor system designed specifically for a conventional turbofan engine. The electronic circuit is based on a Clapp-type oscillator that incorporates a 6H-SiC MESFET, a SiCN MEMS capacitive pressure sensor, titanate MIM capacitors, wirewound inductors, and thick film resistors. The pressure sensor serves as the capacitor in the LC tank circuit, thereby linking pressure to the resonant frequency of the oscillator. The oscillator and DC bias circuitry were fabricated on an alumina substrate and secured inside a metal housing. The packaged sensing system reliably operates at 0 to 350 psi and 25 to 540C. The system has a pressure sensitivity of 6.8 x 10E-2 MHzpsi. The packaged system shows negligible difference in frequency response between 25 and 400C. The fully packaged sensor passed standard benchtop acceptance tests and was evaluated on a flight-worthy engine.

Distribution of coronary arterial capacitance in a canine model.

Science.gov (United States)

Lader, A S; Smith, R S; Phillips, G C; McNamee, J E; Abel, F L

1998-03-01

The capacitative properties of the major left coronary arteries, left main (LM), left anterior descending (LAD), and left circumflex (LCX), were studied in 19 open-chest isolated dog hearts. Capacitance was determined by using ramp perfusion and a left ventricular-to-coronary shunt diastolic decay method; both methods gave similar results, indicating a minimal systolic capacitative component. Increased pericardial pressure (PCP), 25 mmHg, was used to experimentally alter transmural wall pressure. The response to increased PCP was different in the LAD vs. LCX; increasing PCP decreased capacitance in the LCX but increased capacitance in the LAD. This may have been due to the different intramural vs. epicardial volume distribution of these vessels and a decrease in intramural tension during increased PCP. Increased PCP decreased LCX capacitance by approximately 13%, but no changes in conductance or zero flow pressure intercept occurred in any of the three vessels, i. e., evidence against the waterfall theory of vascular collapse at these levels of PCP. Coronary arterial capacitance was also linearly related to perfusion pressure.

Long range ultra-high frequency (UHF) radio frequency identification (RFID) antenna design

Science.gov (United States)

Reynolds, Nathan D.

There is an ever-increasing demand for radio frequency identification (RFID) tags that are passive, long range, and mountable on multiple surfaces. Currently, RFID technology is utilized in numerous applications such as supply chain management, access control, and public transportation. With the combination of sensory systems in recent years, the applications of RFID technology have been extended beyond tracking and identifying. This extension includes applications such as environmental monitoring and healthcare applications. The available sensory systems usually operate in the medium or high frequency bands and have a low read range. However, the range limitations of these systems are being overcome by the development of RFID sensors focused on utilizing tags in the ultra-high frequency (UHF) band. Generally, RFID tags have to be mounted to the object that is being identified. Often the objects requiring identification are metallic. The inherent properties of metallic objects have substantial effects on nearby electromagnetic radiation; therefore, the operation of the tag antenna is affected when mounted on a metallic surface. This outlines one of the most challenging problems for RFID systems today: the optimization of tag antenna performance in a complex environment. In this research, a novel UHF RFID tag antenna, which has a low profile, long range, and is mountable on metallic surfaces, is designed analytically and simulated using a 3-D electromagnetic simulator, ANSYS HFSS. A microstrip patch antenna is selected as the antenna structure, as patch antennas are low profile and suitable for mounting on metallic surfaces. Matching and theoretical models of the microstrip patch antenna are investigated. Once matching and theory of a microstrip patch antenna is thoroughly understood, a unique design technique using electromagnetic band gap (EBG) structures is explored. This research shows that the utilization of an EBG structure in the patch antenna design yields

Effects of wind turbines on UHF television reception: field tests in Denmark, November 1991

International Nuclear Information System (INIS)

Wright, D.T.

1992-01-01

As a result of a planning application for a wind farm comprising 20 wind turbines at Tynewydd Farm, Gilfach Goch in Mid Glamorgan, it became necessary to produce a Report discussing any detrimental effects the proposal might have on UHF television reception. In order to make that Report as definitive as possible, it was decided to carry out field tests on the exact model of wind turbine to be used to Tynewydd. This required a field trip to Denmark, and the opportunity was taken to make measurements on two other models of turbine at the same time. This Report presents the analysis of the results for all three turbines. (Author)

Annealing effects on recombinative activity of nickel at direct silicon bonded interface

International Nuclear Information System (INIS)

Kojima, Takuto; Ohshita, Yoshio; Yamaguchi, Masafumi

2015-01-01

By performing capacitance transient analyses, the recombination activity at a (110)/(100) direct silicon bonded (DSB) interface contaminated with nickel diffused at different temperatures, as a model of grain boundaries in multicrystalline silicon, was studied. The trap level depth from the valence band, trap density of states, and hole capture cross section peaked at an annealing temperature of 300 °C. At temperatures ⩾400 °C, the hole capture cross section increased with temperature, but the density of states remained unchanged. Further, synchrotron-based X-ray analyses, microprobe X-ray fluorescence (μ-XRF), and X-ray absorption near edge structure (XANES) analyses were performed. The analysis results indicated that the chemical phase after the sample was annealed at 200 °C was a mixture of NiO and NiSi 2

Solid-state Memory on Flexible Silicon for Future Electronic Applications

KAUST Repository

Ghoneim, Mohamed

2016-11-01

Advancements in electronics research triggered a vision of a more connected world, touching new unprecedented fields to improve the quality of our lives. This vision has been fueled by electronic giants showcasing flexible displays for the first time in consumer electronics symposiums. Since then, the scientific and research communities partook on exploring possibilities for making flexible electronics. Decades of research have revealed many routes to flexible electronics, lots of opportunities and challenges. In this work, we focus on our contributions towards realizing a complimentary approach to flexible inorganic high performance electronic memories on silicon. This approach provides a straight forward method for capitalizing on the existing well-established semiconductor infrastructure, standard processes and procedures, and collective knowledge. Ultimately, we focus on understanding the reliability and functionality anomalies in flexible electronics and flexible solid state memory built using the flexible silicon platform. The results of the presented studies show that: (i) flexible devices fabricated using etch-protect-release approach (with trenches included in the active area) exhibit ~19% lower safe operating voltage compared to their bulk counterparts, (ii) they can withstand prolonged bending duration (static stress) but are prone to failure under dynamic stress as in repeated bending and re-flattening, (iii) flexible 3D FinFETs exhibit ~10% variation in key properties when exposed to out-of-plane bending stress and out-of-plane stress does not resemble the well-studied in-plane stress used in strain engineering, (iv) resistive memories can be achieved on flexible silicon and their basic resistive property is preserved but other memory functionalities (retention, endurance, speed, memory window) requires further investigations, (v) flexible silicon based PZT ferroelectric capacitors exhibit record polarization, capacitance, and endurance (1 billion

Structure-based capacitance modeling and power loss analysis for the latest high-performance slant field-plate trench MOSFET

Science.gov (United States)

Kobayashi, Kenya; Sudo, Masaki; Omura, Ichiro

2018-04-01

Field-plate trench MOSFETs (FP-MOSFETs), with the features of ultralow on-resistance and very low gate–drain charge, are currently the mainstream of high-performance applications and their advancement is continuing as low-voltage silicon power devices. However, owing to their structure, their output capacitance (C oss), which leads to main power loss, remains to be a problem, especially in megahertz switching. In this study, we propose a structure-based capacitance model of FP-MOSFETs for calculating power loss easily under various conditions. Appropriate equations were modeled for C oss curves as three divided components. Output charge (Q oss) and stored energy (E oss) that were calculated using the model corresponded well to technology computer-aided design (TCAD) simulation, and we validated the accuracy of the model quantitatively. In the power loss analysis of FP-MOSFETs, turn-off loss was sufficiently suppressed, however, mainly Q oss loss increased depending on switching frequency. This analysis reveals that Q oss may become a significant issue in next-generation high-efficiency FP-MOSFETs.

CODA : Compact front-end analog ASIC for silicon detectors

International Nuclear Information System (INIS)

Chandratre, V.B.; Sardesai, S.V.; Kataria, S.K.

2004-01-01

The paper presents the design of a front-end signal processing ASIC to be used with Silicon detectors having full depletion capacitance up to 40 pf. The ASIC channel consists of a charge amplifier, a shaper amplifier (CR-RC 3 ) and a comparator. There is provision for changing gain and polarity. The circuit has an estimated power dissipation of 16 mw. The ASIC is fabricated in 1.2 um CMOS technology. The 0pf noise is ∼400e. The chip has an area of 3 by 4 mm is packaged in 48 pin CLCC and COB option (Chip on Board). (author)

Study of the coastal atmospheric boundary layer during ESCOMPTE 2001. Evaluation and improvement of the efficiency of a UHF radar; Etude de la couche limite atmospherique cotiere durant ESCOMPTE 2001. Evaluation et amelioration des performances d'un radar UHF

Energy Technology Data Exchange (ETDEWEB)

Puygrenier, V

2005-12-15

Forecasting of pollution events was the main objective of the ESCOMPTE-2001 campaign, which took place in the Marseille/Fos/Berre heterogeneous area (southeastern France) in the early summer 2001. This goal requires good understanding and taking into account, by physico-chemical numerical models, of the physical processes in the Atmospheric Boundary Layer (ABL), in which pollutants are emitted, transported and diffused. In the ESCOMPTE-2001 campaign context, this work was devoted to study the low troposphere during sea breeze events, related to meteorological conditions responsible for poor air quality of coastal areas. It presents notably an oscillation of the sea breeze intensity and competitions of locals and regional sea breeze, which change the advective time of the marine air above the continental surface and thus influence the ABL development and its pollutants concentration. This study is based principally on the network of four UHF wind profilers radars set up on the coastal area of Marseille/Fos/Berre, allowing a continuous three-dimensional description of the sea breeze flow and the ABL. For the needs of this phenomenological work, methodological developments was realized to improve the measurement of ABL turbulent properties with UHF radars (terms of turbulent kinetic energy budget) and the use of wind profilers network for the study of pollutants plumes trajectory-graphy. (author)

Switchless charge-discharge circuit for electrical capacitance tomography

International Nuclear Information System (INIS)

Kryszyn, J; Smolik, W T; Radzik, B; Olszewski, T; Szabatin, R

2014-01-01

The main factor limiting the performance of electrical capacitance tomography (ECT) is an extremely low value of inter-electrode capacitances. The charge-discharge circuit is a well suited circuit for a small capacitance measurement due to its immunity to noise and stray capacitance, although it has a problem associated with a charge injected by the analogue switches, which results in a dc offset. This paper presents a new diode-based circuit for capacitance measurement in which a charge transfer method is realized without switches. The circuit was built and tested in one channel configuration with 16 multiplexed electrodes. The performance of the elaborated circuit and a comparison with a classic charge-discharge circuit are presented. The elaborated circuit can be used for sensors with inter-electrode capacitances not lower than 10 fF. The presented approach allows us to obtain a similar performance to the classic charge-discharge circuit, but has a simplified design. A lack of the need to synchronize the analogue switches in the transmitter and the receiver part of this circuit could be a desirable feature in the design of measurement systems integrated with electrodes. (paper)

Electrosorption capacitance of nanostructured carbon-based materials.

Science.gov (United States)

Hou, Chia-Hung; Liang, Chengdu; Yiacoumi, Sotira; Dai, Sheng; Tsouris, Costas

2006-10-01

The fundamental mechanism of electrosorption of ions developing a double layer inside nanopores was studied via a combination of experimental and theoretical studies. A novel graphitized-carbon monolithic material has proven to be a good electrical double-layer capacitor that can be applied in the separation of ions from aqueous solutions. An extended electrical double-layer model indicated that the pore size distribution plays a key role in determining the double-layer capacitance in an electrosorption process. Because of the occurrence of double-layer overlapping in narrow pores, mesopores and micropores make significantly different contributions to the double-layer capacitance. Mesopores show good electrochemical accessibility. Micropores present a slow mass transfer of ions and a considerable loss of double-layer capacitance, associated with a shallow potential distribution inside pores. The formation of the diffuse layer inside the micropores determines the magnitude of the double-layer capacitance at low electrolyte concentrations and at conditions close to the point of zero charge of the material. The effect of the double-layer overlapping on the electrosorption capacitance can be reduced by increasing the pore size, electrolyte concentration, and applied potential. The results are relevant to water deionization.

A 45.8fJ/Step, energy-efficient, differential SAR capacitance-to-digital converter for capacitive pressure sensing

KAUST Repository

Alhoshany, Abdulaziz

2016-05-03

An energy-efficient readout circuit for a capacitive sensor is presented. The capacitive sensor is digitized by a 12-bit energy efficient capacitance-to-digital converter (CDC) that is based on a differential successive-approximation architecture. This CDC meets extremely low power requirements by using an operational transconductance amplifier (OTA) that is based on a current-starved inverter. It uses a charge-redistribution DAC that involves coarse-fine architecture. We split the DAC into a coarse-DAC and a fine-DAC to allow a wide capacitance range in a compact area. It covers a wide range of capacitance of 16.14 pF with a 4.5 fF absolute resolution. An analog comparator is implemented by cross-coupling two 3-input NAND gates to enable power and area efficient operation. The prototype CDC was fabricated using a standard 180 nm CMOS technology. The 12-bit CDC has a measurement time of 42.5 μs, and consumes 3.54 μW and 0.29 μW from analog and digital supplies, respectively. This corresponds to a state-of-the-art figure-of-merit (FoM) of 45.8 fJ/conversion-step. © 2016 Elsevier B.V. All rights reserved.

A 45.8fJ/Step, energy-efficient, differential SAR capacitance-to-digital converter for capacitive pressure sensing

KAUST Repository

Alhoshany, Abdulaziz; Omran, Hesham; Salama, Khaled N.

2016-01-01

An energy-efficient readout circuit for a capacitive sensor is presented. The capacitive sensor is digitized by a 12-bit energy efficient capacitance-to-digital converter (CDC) that is based on a differential successive-approximation architecture. This CDC meets extremely low power requirements by using an operational transconductance amplifier (OTA) that is based on a current-starved inverter. It uses a charge-redistribution DAC that involves coarse-fine architecture. We split the DAC into a coarse-DAC and a fine-DAC to allow a wide capacitance range in a compact area. It covers a wide range of capacitance of 16.14 pF with a 4.5 fF absolute resolution. An analog comparator is implemented by cross-coupling two 3-input NAND gates to enable power and area efficient operation. The prototype CDC was fabricated using a standard 180 nm CMOS technology. The 12-bit CDC has a measurement time of 42.5 μs, and consumes 3.54 μW and 0.29 μW from analog and digital supplies, respectively. This corresponds to a state-of-the-art figure-of-merit (FoM) of 45.8 fJ/conversion-step. © 2016 Elsevier B.V. All rights reserved.

Designing 3D Multihierarchical Heteronanostructures for High-Performance On-Chip Hybrid Supercapacitors: Poly(3,4-(ethylenedioxy)thiophene)-Coated Diamond/Silicon Nanowire Electrodes in an Aprotic Ionic Liquid.

Science.gov (United States)

Aradilla, David; Gao, Fang; Lewes-Malandrakis, Georgia; Müller-Sebert, Wolfgang; Gentile, Pascal; Boniface, Maxime; Aldakov, Dmitry; Iliev, Boyan; Schubert, Thomas J S; Nebel, Christoph E; Bidan, Gérard

2016-07-20

A versatile and robust hierarchically multifunctionalized nanostructured material made of poly(3,4-(ethylenedioxy)thiophene) (PEDOT)-coated diamond@silicon nanowires has been demonstrated to be an excellent capacitive electrode for supercapacitor devices. Thus, the electrochemical deposition of nanometric PEDOT films on diamond-coated silicon nanowire (SiNW) electrodes using N-methyl-N-propylpyrrolidinium bis((trifluoromethyl)sulfonyl)imide ionic liquid displayed a specific capacitance value of 140 F g(-1) at a scan rate of 1 mV s(-1). The as-grown functionalized electrodes were evaluated in a symmetric planar microsupercapacitor using butyltrimethylammonium bis((trifluoromethyl)sulfonyl)imide aprotic ionic liquid as the electrolyte. The device exhibited extraordinary energy and power density values of 26 mJ cm(-2) and 1.3 mW cm(-2) within a large voltage cell of 2.5 V, respectively. In addition, the system was able to retain 80% of its initial capacitance after 15 000 galvanostatic charge-discharge cycles at a high current density of 1 mA cm(-2) while maintaining a Coulombic efficiency around 100%. Therefore, this multifunctionalized hybrid device represents one of the best electrochemical performances concerning coated SiNW electrodes for a high-energy advanced on-chip supercapacitor.

Feasibility of novel four degrees of freedom capacitive force sensor for skin interface force

Directory of Open Access Journals (Sweden)

Murakami Chisato

2012-11-01

Full Text Available Abstract Background The objective of our study was to develop a novel capacitive force sensor that enables simultaneous measurements of yaw torque around the pressure axis and normal force and shear forces at a single point for the purpose of elucidating pressure ulcer pathogenesis and establishing criteria for selection of cushions and mattresses. Methods Two newly developed sensors (approximately 10 mm×10 mm×5 mm (10 and 20 mm×20 mm×5 mm (20 were constructed from silicone gel and four upper and lower electrodes. The upper and lower electrodes had sixteen combinations that had the function as capacitors of parallel plate type. The full scale (FS ranges of force/torque were defined as 0–1.5 N, –0.5-0.5 N and −1.5-1.5 N mm (10 and 0–8.7 N, –2.9-2.9 N and −16.8-16.8 N mm (20 in normal force, shear forces and yaw torque, respectively. The capacitances of sixteen capacitors were measured by an LCR meter (AC1V, 100 kHz when displacements corresponding to four degrees of freedom (DOF forces within FS ranges were applied to the sensor. The measurement was repeated three times in each displacement condition (10 only. Force/torque were calculated by corrected capacitance and were evaluated by comparison to theoretical values and standard normal force measured by an universal tester. Results In measurements of capacitance, the coefficient of variation was 3.23% (10. The Maximum FS errors of estimated force/torque were less than or equal to 10.1 (10 and 16.4% (20, respectively. The standard normal forces were approximately 1.5 (10 and 9.4 N (20 when pressure displacements were 3 (10 and 2 mm (20, respectively. The estimated normal forces were approximately 1.5 (10 and 8.6 N (10 in the same condition. Conclusions In this study, we developed a new four DOF force sensor for measurement of force/torque that occur between the skin and a mattress. In measurement of capacitance, the repeatability was good and it was confirmed that the sensor had

Design of an ultra-low-power digital processor for passive UHF RFID tags

Energy Technology Data Exchange (ETDEWEB)

Shi Wanggen; Zhuang Yiqi; Li Xiaoming; Wang Xianghua; Jin Zhao; Wang Dan, E-mail: wanggen_shi@163.co [Key Laboratory of the Ministry of Education for Wide Band-Gap Semiconductor Materials and Devices, Institute of Microelectronics, Xidian University, Xi' an 710071 (China)

2009-04-15

A new architecture of digital processors for passive UHF radio-frequency identification tags is proposed. This architecture is based on ISO/IEC 18000-6C and targeted at ultra-low power consumption. By applying methods like system-level power management, global clock gating and low voltage implementation, the total power of the design is reduced to a few microwatts. In addition, an innovative way for the design of a true RNG is presented, which contributes to both low power and secure data transaction. The digital processor is verified by an integrated FPGA platform and implemented by the Synopsys design kit for ASIC flows. The design fits different CMOS technologies and has been taped out using the 2P4M 0.35 mum process of Chartered Semiconductor.

Design of double capacitances infrasonic receiver

International Nuclear Information System (INIS)

Wang Changhai; Han Kuixia; Wang Fei

2003-01-01

The article introduces the theory of infrasonic generation and reception of nuclear explosion. An idea of the design of double capacitances infrasonic receiver using CPLD technology is given in it. Compare with the single capacitance infrasonic receiver, sensitivity of the improved receiver can be improved scores of times, dynamic range can be improved largely, and the whole performance gets improvement a lots

Interdigitated electrodes as impedance and capacitance biosensors: A review

Science.gov (United States)

Mazlan, N. S.; Ramli, M. M.; Abdullah, M. M. A. B.; Halin, D. S. C.; Isa, S. S. M.; Talip, L. F. A.; Danial, N. S.; Murad, S. A. Z.

2017-09-01

Interdigitated electrodes (IDEs) are made of two individually addressable interdigitated comb-like electrode structures. IDEs are one of the most favored transducers, widely utilized in technological applications especially in the field of biological and chemical sensors due to their inexpensive, ease of fabrication process and high sensitivity. In order to detect and analyze a biochemical molecule or analyte, the impedance and capacitance signal need to be obtained. This paper investigates the working principle and influencer of the impedance and capacitance biosensors. The impedance biosensor depends on the resistance and capacitance while the capacitance biosensor influenced by the dielectric permittivity. However, the geometry and structures of the interdigitated electrodes affect both impedance and capacitance biosensor. The details have been discussed in this paper.

Multi-Channel Capacitive Sensor Arrays

Directory of Open Access Journals (Sweden)

Bingnan Wang

2016-01-01

Full Text Available In this paper, multi-channel capacitive sensor arrays based on microstrip band-stop filters are studied. The sensor arrays can be used to detect the proximity of objects at different positions and directions. Each capacitive sensing structure in the array is connected to an inductive element to form resonance at different frequencies. The resonances are designed to be isolated in the frequency spectrum, such that the change in one channel does not affect resonances at other channels. The inductive element associated with each capacitive sensor can be surface-mounted inductors, integrated microstrip inductors or metamaterial-inspired structures. We show that by using metamaterial split-ring structures coupled to a microstrip line, the quality factor of each resonance can be greatly improved compared to conventional surface-mounted or microstrip meander inductors. With such a microstrip-coupled split-ring design, more sensing elements can be integrated in the same frequency spectrum, and the sensitivity can be greatly improved.

Bioenergetics of mammalian sperm capacitation.

Science.gov (United States)

Ferramosca, Alessandra; Zara, Vincenzo

2014-01-01

After ejaculation, the mammalian male gamete must undergo the capacitation process, which is a prerequisite for egg fertilization. The bioenergetics of sperm capacitation is poorly understood despite its fundamental role in sustaining the biochemical and molecular events occurring during gamete activation. Glycolysis and mitochondrial oxidative phosphorylation (OXPHOS) are the two major metabolic pathways producing ATP which is the primary source of energy for spermatozoa. Since recent data suggest that spermatozoa have the ability to use different metabolic substrates, the main aim of this work is to present a broad overview of the current knowledge on the energy-producing metabolic pathways operating inside sperm mitochondria during capacitation in different mammalian species. Metabolism of glucose and of other energetic substrates, such as pyruvate, lactate, and citrate, is critically analyzed. Such knowledge, besides its obvious importance for basic science, could eventually translate into the development of novel strategies for treatment of male infertility, artificial reproduction, and sperm selection methods.

A robust parasitic-insensitive successive approximation capacitance-to-digital converter

KAUST Repository

Omran, Hesham

2014-09-01

In this paper, we present a capacitive sensor digital interface circuit using true capacitance-domain successive approximation that is independent of supply voltage. Robust operation is achieved by using a charge amplifier stage and multiple comparison technique. The interface circuit is insensitive to parasitic capacitances, offset voltages, and charge injection, and is not prone to noise coupling. The proposed design achieves very low temperature sensitivity of 25ppm/oC. A coarse-fine programmable capacitance array allows digitizing a wide capacitance range of 16pF with 12.5-bit quantization limited resolution in a compact area of 0.07mm2. The fabricated prototype is experimentally verified using on-chip sensor and off-chip MEMS capacitive pressure sensor. © 2014 IEEE.

A robust parasitic-insensitive successive approximation capacitance-to-digital converter

KAUST Repository

Omran, Hesham; Arsalan, Muhammad; Salama, Khaled N.

2014-01-01

In this paper, we present a capacitive sensor digital interface circuit using true capacitance-domain successive approximation that is independent of supply voltage. Robust operation is achieved by using a charge amplifier stage and multiple comparison technique. The interface circuit is insensitive to parasitic capacitances, offset voltages, and charge injection, and is not prone to noise coupling. The proposed design achieves very low temperature sensitivity of 25ppm/oC. A coarse-fine programmable capacitance array allows digitizing a wide capacitance range of 16pF with 12.5-bit quantization limited resolution in a compact area of 0.07mm2. The fabricated prototype is experimentally verified using on-chip sensor and off-chip MEMS capacitive pressure sensor. © 2014 IEEE.

Synthesis of microsphere silicon carbide/nanoneedle manganese oxide composites and their electrochemical properties as supercapacitors

Science.gov (United States)

Kim, Myeongjin; Yoo, Youngjae; Kim, Jooheon

2014-11-01

Synthesis of microsphere silicon carbide/nanoneedle MnO2 (SiC/N-MnO2) composites for use as high-performance materials in supercapacitors is reported herein. The synthesis procedure involves the initial treatment of silicon carbide (SiC) with hydrogen peroxide to obtain oxygen-containing functional groups to provide anchoring sites for connection of SiC and the MnO2 nanoneedles (N-MnO2). MnO2 nanoneedles are subsequently formed on the SiC surface. The morphology and microstructure of the as-prepared composites are characterized via X-ray diffractometry, field-emission scanning electron microscopy, thermogravimetric analysis, and X-ray photoelectron spectroscopy. The characterizations indicate that MnO2 nanoneedles are homogeneously formed on the SiC surface in the composite. The capacitive properties of the as-prepared SiC/N-MnO2 electrodes are evaluated using cyclic voltammetry, galvanostatic charge/discharge testing, and electrochemical impedance spectroscopy in a three-electrode experimental setup using a 1-M Na2SO4 aqueous solution as the electrolyte. The SiC/N-MnO2(5) electrode, for which the MnO2/SiC feed ratio is 5:1, displays a specific capacitance as high as 273.2 F g-1 at 10 mV s-1.

Study of the coastal atmospheric boundary layer during ESCOMPTE 2001. Evaluation and improvement of the efficiency of a UHF radar; Etude de la couche limite atmospherique cotiere durant ESCOMPTE 2001. Evaluation et amelioration des performances d'un radar UHF

Energy Technology Data Exchange (ETDEWEB)

Puygrenier, V.

2005-12-15

Forecasting of pollution events was the main objective of the ESCOMPTE-2001 campaign, which took place in the Marseille/Fos/Berre heterogeneous area (southeastern France) in the early summer 2001. This goal requires good understanding and taking into account, by physico-chemical numerical models, of the physical processes in the Atmospheric Boundary Layer (ABL), in which pollutants are emitted, transported and diffused. In the ESCOMPTE-2001 campaign context, this work was devoted to study the low troposphere during sea breeze events, related to meteorological conditions responsible for poor air quality of coastal areas. It presents notably an oscillation of the sea breeze intensity and competitions of locals and regional sea breeze, which change the advective time of the marine air above the continental surface and thus influence the ABL development and its pollutants concentration. This study is based principally on the network of four UHF wind profilers radars set up on the coastal area of Marseille/Fos/Berre, allowing a continuous three-dimensional description of the sea breeze flow and the ABL. For the needs of this phenomenological work, methodological developments was realized to improve the measurement of ABL turbulent properties with UHF radars (terms of turbulent kinetic energy budget) and the use of wind profilers network for the study of pollutants plumes trajectory-graphy. (author)

A CMOS 130nm Evaluation digitzer chip for silicon strips readout

CERN Document Server

Da Silva, W; Dhellot, M; Fougeron, D; Genat, J F; Hermel, R; Huppert, J f; Kapusta, F; Lebbolo, H; Pham, T H; Rossel, F; Savoy-navarro, A; Sefri, R; Vilalte

2007-01-01

A CMOS 130nm evaluation chip intended to read Silicon strip detectors at the ILC has been designed and successfully tested. Optimized for a detector capacitance of 10 pF, it includes four channels of charge integration, pulse shaping, a 16-deep analogue sampler triggered on input analogue sums, and parallel analogue to digital conversion. Tests results of the full chain are reported, demonstrating the behaviour and performance of the full sampling process and analogue to digital conversion. Each channel dissipates less than one milli-Watt static power.

A reciprocity-based formula for the capacitance with quadrupolar electrodes

Energy Technology Data Exchange (ETDEWEB)

Cho, Sungbo [Gachon University of Medicine and Science, Incheon (Korea, Republic of)

2011-11-15

A new capacitance formula for the practical design and characterization of quadrupolar electrode arrays with capacitive structures was derived based on the reciprocal theorem. The reciprocity-based capacitance formula agreed with the empirical equations established to estimate the capacitance of a single strip line or disk electrode compensating for the fringing field effect that occurs at the electrode edge. The reciprocity-based formula was applied to compute the capacitance measurable by using a quadrupolar square electrode array with a symmetric dipole-dipole configuration and was compared with the analytical equation established based on the image method assuming that the electrodes were points. The results showed that the capacitance of the quadrupolar electrodes was determined by the size of the quadrupolar electrodes relative to the separation distance between the electrodes and that the reciprocity-based capacitance formula was in agreement with the established analytical equation if the separated distance between the electrodes relative to the electrode size was large enough.

A reciprocity-based formula for the capacitance with quadrupolar electrodes

International Nuclear Information System (INIS)

Cho, Sungbo

2011-01-01

A new capacitance formula for the practical design and characterization of quadrupolar electrode arrays with capacitive structures was derived based on the reciprocal theorem. The reciprocity-based capacitance formula agreed with the empirical equations established to estimate the capacitance of a single strip line or disk electrode compensating for the fringing field effect that occurs at the electrode edge. The reciprocity-based formula was applied to compute the capacitance measurable by using a quadrupolar square electrode array with a symmetric dipole-dipole configuration and was compared with the analytical equation established based on the image method assuming that the electrodes were points. The results showed that the capacitance of the quadrupolar electrodes was determined by the size of the quadrupolar electrodes relative to the separation distance between the electrodes and that the reciprocity-based capacitance formula was in agreement with the established analytical equation if the separated distance between the electrodes relative to the electrode size was large enough.

Measurement Error Estimation for Capacitive Voltage Transformer by Insulation Parameters

Directory of Open Access Journals (Sweden)

Bin Chen

2017-03-01

Full Text Available Measurement errors of a capacitive voltage transformer (CVT are relevant to its equivalent parameters for which its capacitive divider contributes the most. In daily operation, dielectric aging, moisture, dielectric breakdown, etc., it will exert mixing effects on a capacitive divider’s insulation characteristics, leading to fluctuation in equivalent parameters which result in the measurement error. This paper proposes an equivalent circuit model to represent a CVT which incorporates insulation characteristics of a capacitive divider. After software simulation and laboratory experiments, the relationship between measurement errors and insulation parameters is obtained. It indicates that variation of insulation parameters in a CVT will cause a reasonable measurement error. From field tests and calculation, equivalent capacitance mainly affects magnitude error, while dielectric loss mainly affects phase error. As capacitance changes 0.2%, magnitude error can reach −0.2%. As dielectric loss factor changes 0.2%, phase error can reach 5′. An increase of equivalent capacitance and dielectric loss factor in the high-voltage capacitor will cause a positive real power measurement error. An increase of equivalent capacitance and dielectric loss factor in the low-voltage capacitor will cause a negative real power measurement error.

A study for the detection of ionizing particles with phototransistors on thick high-resistivity silicon substrates

International Nuclear Information System (INIS)

Batignani, G.; Angelini, C.; Bisogni, M.G.; Boscardin, M.; Bettarini, S.; Bondioli, M.; Bosisio, L.; Bucci, F.; Calderini, G.; Carpinelli, M.; Ciacchi, M.; Dalla Betta, G.F.; Dittongo, S.; Forti, F.; Giorgi, M.A.; Gregori, P.; Han, D.J.; Manfredi, P.F.; Manghisoni, M.; Marchiori, G.; Neri, N.; Novelli, M.; Paoloni, E.; Piemonte, C.; Rachevskaia, I.; Rama, M.; Ratti, L.; Re, V.; Rizzo, G.; Ronchin, S.; Rosso, V.; Simi, G.; Speziali, V.; Stefanini, A.; Zorzi, N.

2004-01-01

We report on bipolar NPN phototransistors fabricated at ITC-IRST on thick high-resistivity silicon substrates. The phototransistor emitter is composed of a phosphorus n+ implant, the base is a diffused high-energy boron implant, and the collector is the 600-800 μm thick silicon bulk, contacted on the backplane. We have studied the current amplification for two different doping profiles of the emitter, obtaining values of β ranging from 60 to 3000. For various emitter and base configurations, we measured the static device characteristics and extracted the leakage currents and the base resistance, verifying the fundamental relationship between them and the total base capacitances. The use of such phototransistors to detect ionizing particles is exploited and discussed

A study for the detection of ionizing particles with phototransistors on thick high-resistivity silicon substrates

Energy Technology Data Exchange (ETDEWEB)

Batignani, G. E-mail: giovanni.batignani@pi.infn.it; Angelini, C.; Bisogni, M.G.; Boscardin, M.; Bettarini, S.; Bondioli, M.; Bosisio, L.; Bucci, F.; Calderini, G.; Carpinelli, M.; Ciacchi, M.; Dalla Betta, G.F.; Dittongo, S.; Forti, F.; Giorgi, M.A.; Gregori, P.; Han, D.J.; Manfredi, P.F.; Manghisoni, M.; Marchiori, G.; Neri, N.; Novelli, M.; Paoloni, E.; Piemonte, C.; Rachevskaia, I.; Rama, M.; Ratti, L.; Re, V.; Rizzo, G.; Ronchin, S.; Rosso, V.; Simi, G.; Speziali, V.; Stefanini, A.; Zorzi, N

2004-09-01

We report on bipolar NPN phototransistors fabricated at ITC-IRST on thick high-resistivity silicon substrates. The phototransistor emitter is composed of a phosphorus n+ implant, the base is a diffused high-energy boron implant, and the collector is the 600-800 {mu}m thick silicon bulk, contacted on the backplane. We have studied the current amplification for two different doping profiles of the emitter, obtaining values of {beta} ranging from 60 to 3000. For various emitter and base configurations, we measured the static device characteristics and extracted the leakage currents and the base resistance, verifying the fundamental relationship between them and the total base capacitances. The use of such phototransistors to detect ionizing particles is exploited and discussed.

Development trends of combined inductance-capacitance electromechanical energy converters

Directory of Open Access Journals (Sweden)

Karayan Hamlet

2018-01-01

Full Text Available In the article the modern state of completely new direction of electromechanical science such as combined inductive-capacitive electromechanics is considered. The wide spectra of its possible practical applications and prospects for further development are analyzed. A new approach for mathematical description of transients in dualcon jugate dynamic systems is proposed. On the basis of the algorithm differential equations for inductive-capacitive compatible electromechanical energy converters are derived. The generalized Lagrangian theory of combined inductively-capacitive electric machines was developed as a union of generalized Lagrangian models of inductive and capacitive electro-mechanical energy converters developed on the basis of the basic principles of binary-conjugate electrophysics. The author gives equations of electrodynamics and electromechanics of combined inductive-capacitive electric machines in case there are active electrotechnical materials of dual purpose (ferroelectromagnets in the structure of their excitation system. At the same time, the necessary Lagrangian for combined inductive-capacitive forces was built using new technologies of interaction between inductive and capacitive subsystems. The joint solution of these equations completely determines the dynamic behavior and energy characteristics of the generalized model of combined machines of any design and in any modes of interaction of their functional elements

FRONT-END ASIC FOR A SILICON COMPTON TELESCOPE.

Energy Technology Data Exchange (ETDEWEB)

DE GERONIMO,G.; FRIED, J.; FROST, E.; PHLIPS, B.; VERNON, E.; WULF, E.A.

2007-10-27

We describe a front-end application specific integrated circuit (ASIC) developed for a silicon Compton telescope. Composed of 32 channels, it reads out signals in both polarities from each side of a Silicon strip sensor, 2 mm thick 27 cm long, characterized by a strip capacitance of 30 pF. Each front-end channel provides low-noise charge amplification, shaping with a stabilized baseline, discrimination, and peak detection with an analog memory. The channels can process events simultaneously, and the read out is sparsified. The charge amplifier makes uses a dual-cascode configuration and dual-polarity adaptive reset, The low-hysteresis discriminator and the multi-phase peak detector process signals with a dynamic range in excess of four hundred. An equivalent noise charge (ENC) below 200 electrons was measured at 30 pF, with a slope of about 4.5 electrons/pF at a peaking time of 4 {micro}s. With a total dissipated power of 5 mW the channel covers an energy range up to 3.2 MeV.

Evaluation of Pressure Capacitive Sensors for Application in Grasping and Manipulation Analysis.

Science.gov (United States)

Pessia, Paola; Cordella, Francesca; Schena, Emiliano; Davalli, Angelo; Sacchetti, Rinaldo; Zollo, Loredana

2017-12-08

The analysis of the human grasping and manipulation capabilities is paramount for investigating human sensory-motor control and developing prosthetic and robotic hands resembling the human ones. A viable solution to perform this analysis is to develop instrumented objects measuring the interaction forces with the hand. In this context, the performance of the sensors embedded in the objects is crucial. This paper focuses on the experimental characterization of a class of capacitive pressure sensors suitable for biomechanical analysis. The analysis was performed in three loading conditions (Distributed load, 9 Tips load, and Wave-shaped load, thanks to three different inter-elements) via a traction/compression testing machine. Sensor assessment was also carried out under human- like grasping condition by placing a silicon material with the same properties of prosthetic cosmetic gloves in between the sensor and the inter-element in order to simulate the human skin. Data show that the input-output relationship of the analyzed, sensor is strongly influenced by both the loading condition (i.e., type of inter-element) and the grasping condition (with or without the silicon material). This needs to be taken into account to avoid significant measurement error. To go over this hurdle, the sensors have to be calibrated under each specific condition in order to apply suitable corrections to the sensor output and significantly improve the measurement accuracy.

Capacitance-Power-Hysteresis Trilemma in Nanoporous Supercapacitors

Directory of Open Access Journals (Sweden)

Alpha A. Lee

2016-06-01

Full Text Available Nanoporous supercapacitors are an important player in the field of energy storage that fill the gap between dielectric capacitors and batteries. The key challenge in the development of supercapacitors is the perceived trade-off between capacitance and power delivery. Current efforts to boost the capacitance of nanoporous supercapacitors focus on reducing the pore size so that they can only accommodate a single layer of ions. However, this tight packing compromises the charging dynamics and hence power density. We show via an analytical theory and Monte Carlo simulations that charging is sensitively dependent on the affinity of ions to the pores, and that high capacitances can be obtained for ionophobic pores of widths significantly larger than the ion diameter. Our theory also predicts that charging can be hysteretic with a significant energy loss per cycle for intermediate ionophilicities. We use these observations to explore the parameter regimes in which a capacitance-power-hysteresis trilemma may be avoided.

A capacitive ECG array with visual patient feedback.

Science.gov (United States)

Eilebrecht, Benjamin; Schommartz, Antje; Walter, Marian; Wartzek, Tobias; Czaplik, Michael; Leonhardt, Steffen

2010-01-01

Capacitive electrocardiogram (ECG) sensing is a promising technique for less constraining vital signal measurement and close to a commercial application. Even bigger trials testing the diagnostic significance were already done with single lead systems. Anyway, most applications to be found in research are limited to one channel and thus limited in its diagnostic relevance as only diseases coming along with a change of the heart rate can be diagnosed adequately. As a consequence the need for capacitive multi-channel ECGs combining the diagnostic relevance and the advantages of capacitive ECG sensing emerges. This paper introduces a capacitive ECG measurement system which allows the recording of standardized ECG leads according to Einthoven and Goldberger by means of an electrode array with nine electrodes.

Annealing effects on recombinative activity of nickel at direct silicon bonded interface

Energy Technology Data Exchange (ETDEWEB)

Kojima, Takuto, E-mail: tkojima@toyota-ti.ac.jp; Ohshita, Yoshio; Yamaguchi, Masafumi [Toyota Technological Institute, 2-12-1 Hisakata, Tempaku-ku, Nagoya, 468-8511 (Japan)

2015-09-15

By performing capacitance transient analyses, the recombination activity at a (110)/(100) direct silicon bonded (DSB) interface contaminated with nickel diffused at different temperatures, as a model of grain boundaries in multicrystalline silicon, was studied. The trap level depth from the valence band, trap density of states, and hole capture cross section peaked at an annealing temperature of 300 °C. At temperatures ⩾400 °C, the hole capture cross section increased with temperature, but the density of states remained unchanged. Further, synchrotron-based X-ray analyses, microprobe X-ray fluorescence (μ-XRF), and X-ray absorption near edge structure (XANES) analyses were performed. The analysis results indicated that the chemical phase after the sample was annealed at 200 °C was a mixture of NiO and NiSi{sub 2}.

Diamond and silicon pixel detectors in high radiation environments

Energy Technology Data Exchange (ETDEWEB)

Tsung, Jieh-Wen

2012-10-15

Diamond pixel detector is a promising candidate for tracking of collider experiments because of the good radiation tolerance of diamond. The diamond pixel detector must withstand the radiation damage from 10{sup 16} particles per cm{sup 2}, which is the expected total fluence in High Luminosity Large Hadron Collider. The performance of diamond and silicon pixel detectors are evaluated in this research in terms of the signal-to-noise ratio (SNR). Single-crystal diamond pixel detectors with the most recent readout chip ATLAS FE-I4 are produced and characterized. Based on the results of the measurement, the SNR of diamond pixel detector is evaluated as a function of radiation fluence, and compared to that of planar-silicon ones. The deterioration of signal due to radiation damage is formulated using the mean free path of charge carriers in the sensor. The noise from the pixel readout circuit is simulated and calculated with leakage current and input capacitance to the amplifier as important parameters. The measured SNR shows good agreement with the calculated and simulated results, proving that the performance of diamond pixel detectors can exceed the silicon ones if the particle fluence is more than 10{sup 15} particles per cm{sup 2}.

Diamond and silicon pixel detectors in high radiation environments

International Nuclear Information System (INIS)

Tsung, Jieh-Wen

2012-10-01

Diamond pixel detector is a promising candidate for tracking of collider experiments because of the good radiation tolerance of diamond. The diamond pixel detector must withstand the radiation damage from 10 16 particles per cm 2 , which is the expected total fluence in High Luminosity Large Hadron Collider. The performance of diamond and silicon pixel detectors are evaluated in this research in terms of the signal-to-noise ratio (SNR). Single-crystal diamond pixel detectors with the most recent readout chip ATLAS FE-I4 are produced and characterized. Based on the results of the measurement, the SNR of diamond pixel detector is evaluated as a function of radiation fluence, and compared to that of planar-silicon ones. The deterioration of signal due to radiation damage is formulated using the mean free path of charge carriers in the sensor. The noise from the pixel readout circuit is simulated and calculated with leakage current and input capacitance to the amplifier as important parameters. The measured SNR shows good agreement with the calculated and simulated results, proving that the performance of diamond pixel detectors can exceed the silicon ones if the particle fluence is more than 10 15 particles per cm 2 .

Negative capacitance in a ferroelectric capacitor.

Science.gov (United States)

Khan, Asif Islam; Chatterjee, Korok; Wang, Brian; Drapcho, Steven; You, Long; Serrao, Claudy; Bakaul, Saidur Rahman; Ramesh, Ramamoorthy; Salahuddin, Sayeef

2015-02-01

The Boltzmann distribution of electrons poses a fundamental barrier to lowering energy dissipation in conventional electronics, often termed as Boltzmann Tyranny. Negative capacitance in ferroelectric materials, which stems from the stored energy of a phase transition, could provide a solution, but a direct measurement of negative capacitance has so far been elusive. Here, we report the observation of negative capacitance in a thin, epitaxial ferroelectric film. When a voltage pulse is applied, the voltage across the ferroelectric capacitor is found to be decreasing with time--in exactly the opposite direction to which voltage for a regular capacitor should change. Analysis of this 'inductance'-like behaviour from a capacitor presents an unprecedented insight into the intrinsic energy profile of the ferroelectric material and could pave the way for completely new applications.

Membrane capacitive deionization

NARCIS (Netherlands)

Biesheuvel, P.M.; Wal, van der A.

2010-01-01

Membrane capacitive deionization (MCDI) is an ion-removal process based on applying an electrical potential difference across an aqueous solution which flows in between oppositely placed porous electrodes, in front of which ion-exchange membranes are positioned. Due to the applied potential, ions

Fabrication of a Micromachined Capacitive Switch Using the CMOS-MEMS Technology

Directory of Open Access Journals (Sweden)

Cheng-Yang Lin

2015-11-01

Full Text Available The study investigates the design and fabrication of a micromachined radio frequency (RF capacitive switch using the complementary metal oxide semiconductor-microelectromechanical system (CMOS-MEMS technology. The structure of the micromachined switch is composed of a membrane, eight springs, four inductors, and coplanar waveguide (CPW lines. In order to reduce the actuation voltage of the switch, the springs are designed as low stiffness. The finite element method (FEM software CoventorWare is used to simulate the actuation voltage and displacement of the switch. The micromachined switch needs a post-CMOS process to release the springs and membrane. A wet etching is employed to etch the sacrificial silicon dioxide layer, and to release the membrane and springs of the switch. Experiments show that the pull-in voltage of the switch is 12 V. The switch has an insertion loss of 0.8 dB at 36 GHz and an isolation of 19 dB at 36 GHz.

cLite – A Capacitive Signal Conditioning IC

Directory of Open Access Journals (Sweden)

Krauss Gudrun

2009-12-01

Full Text Available The ZMD31210 cLite™ – a new member of the ZMDI’s Lite™ family of low-cost sensor signal conditioner (SSC integrated circuits – is described in this paper. The cLite™ is the first conditioner for capacitive sensors. Supporting sensor capacitances from 2 pF up to 260 pF, the new sensor signal conditioner covers a wide range of applications. An important aspect of conditioning a capacitance sensor input signal is the adaptation of the capacitive-to-digital converter (CDC input range to the sensor signal span and offset values in order to maximize accuracy. All typical features of the Lite™ family including the digital calibration math based on EEPROM-stored coefficients and a variety of outputs (I2C™, SPI, PDM, and programmable alarms are integrated in the cLite™ as well. Additional features including a sleep mode and low supply voltage range (down to 2.3 V support the low power concept. The paper focuses in particular on the capacitance sensor adaptation and high precision sensor conditioning.

Electrical behaviour of a silicone elastomer under simulated space environment

International Nuclear Information System (INIS)

Roggero, A; Dantras, E; Paulmier, T; Rejsek-Riba, V; Tonon, C; Dagras, S; Balcon, N; Payan, D

2015-01-01

The electrical behavior of a space-used silicone elastomer was characterized using surface potential decay and dynamic dielectric spectroscopy techniques. In both cases, the dielectric manifestation of the glass transition (dipole orientation) and a charge transport phenomenon were observed. An unexpected linear increase of the surface potential with temperature was observed around T g in thermally-stimulated potential decay experiments, due to molecular mobility limiting dipolar orientation in one hand, and 3D thermal expansion reducing the materials capacitance in the other hand. At higher temperatures, the charge transport process, believed to be thermally activated electron hopping with an activation energy of about 0.4 eV, was studied with and without the silica and iron oxide fillers present in the commercial material. These fillers were found to play a preponderant role in the low-frequency electrical conductivity of this silicone elastomer, probably through a Maxwell–Wagner–Sillars relaxation phenomenon. (paper)

Study on effective MOSFET channel length extracted from gate capacitance

Science.gov (United States)

Tsuji, Katsuhiro; Terada, Kazuo; Fujisaka, Hisato

2018-01-01

The effective channel length (L GCM) of metal-oxide-semiconductor field-effect transistors (MOSFETs) is extracted from the gate capacitances of actual-size MOSFETs, which are measured by charge-injection-induced-error-free charge-based capacitance measurement (CIEF CBCM). To accurately evaluate the capacitances between the gate and the channel of test MOSFETs, the parasitic capacitances are removed by using test MOSFETs having various channel sizes and a source/drain reference device. A strong linear relationship between the gate-channel capacitance and the design channel length is obtained, from which L GCM is extracted. It is found that L GCM is slightly less than the effective channel length (L CRM) extracted from the measured MOSFET drain current. The reason for this is discussed, and it is found that the capacitance between the gate electrode and the source and drain regions affects this extraction.

Reducing the capacitance of piezoelectric film sensors

Energy Technology Data Exchange (ETDEWEB)

González, Martín G., E-mail: mggonza@fi.uba.ar [Grupo de Láser, Óptica de Materiales y Aplicaciones Electromagnéticas (GLOMAE), Departamento de Física, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, C1063ACV Buenos Aires (Argentina); Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), C1425FQB Buenos Aires (Argentina); Sorichetti, Patricio A.; Santiago, Guillermo D. [Grupo de Láser, Óptica de Materiales y Aplicaciones Electromagnéticas (GLOMAE), Departamento de Física, Facultad de Ingeniería, Universidad de Buenos Aires, Paseo Colón 850, C1063ACV Buenos Aires (Argentina)

2016-04-15

We present a novel design for large area, wideband, polymer piezoelectric sensor with low capacitance. The large area allows better spatial resolution in applications such as photoacoustic tomography and the reduced capacitance eases the design of fast transimpedance amplifiers. The metalized piezoelectric polymer thin film is segmented into N sections, electrically connected in series. In this way, the total capacitance is reduced by a factor 1/N{sup 2}, whereas the mechanical response and the active area of the sensor are not modified. We show the construction details for a two-section sensor, together with the impedance spectroscopy and impulse response experimental results that validate the design.

Reducing the capacitance of piezoelectric film sensors

International Nuclear Information System (INIS)

González, Martín G.; Sorichetti, Patricio A.; Santiago, Guillermo D.

2016-01-01

We present a novel design for large area, wideband, polymer piezoelectric sensor with low capacitance. The large area allows better spatial resolution in applications such as photoacoustic tomography and the reduced capacitance eases the design of fast transimpedance amplifiers. The metalized piezoelectric polymer thin film is segmented into N sections, electrically connected in series. In this way, the total capacitance is reduced by a factor 1/N"2, whereas the mechanical response and the active area of the sensor are not modified. We show the construction details for a two-section sensor, together with the impedance spectroscopy and impulse response experimental results that validate the design.

Capacitive-discharge-pumped copper bromide vapour laser

International Nuclear Information System (INIS)

Sukhanov, V B; Fedorov, V F; Troitskii, V O; Gubarev, F A; Evtushenko, Gennadii S

2007-01-01

A copper bromide vapour laser pumped by a high-frequency capacitive discharge is developed. It is shown that, by using of a capacitive discharge, it is possible to built a sealed off metal halide vapour laser of a simple design allowing the addition of active impurities into the working medium. (letters)

Comparative study of mean value of 111 and mean value of 100 crystals and capacitance measurements on Si strip detectors in CSM

International Nuclear Information System (INIS)

Albergo, S.

1999-01-01

For the construction of the silicon microstrip detectors for the tracker of CMS experiment, two different substrate choices were investigated. A high-resistivity substrate with mean value of 111 crystal orientation and a low-resistivity one with mean value of 100 Dirac ket vector crystal orientation. The interstrip and backplane capacitances were measured before and after the exposure to radiation in a range of strip pitches from 60 μm to 240 μm and for values of the width-pitch ratio between 0.1 and 0.5

Thick silicon microstrip detectors simulation for PACT: Pair and Compton Telescope

Science.gov (United States)

Khalil, M.; Laurent, P.; Lebrun, F.; Tatischeff, V.; Dolgorouky, Y.; Bertoli, W.; Breelle, E.

2016-11-01

PACT is a space borne Pair and Compton Telescope that aims to make a sensitive survey of the gamma-ray sky between 100 keV and 100 MeV. It is based upon two main components: a silicon-based gamma-ray tracker and a crystal-based calorimeter. In this paper we will explain the imaging technique of PACT as a Multi-layered Compton telescope (0.1-10 MeV) and its major improvements over its predecessor COMPTEL. Then we will present a simulation study to optimize the silicon tracker of PACT. This tracker is formed of thousands of identical silicon double sided strip detectors (DSSDs). We have developed a simulation model (using SILVACO) to simulate the DSSD performance while varying its thickness, impurity concentration of the bulk material, electrode pitch, and electrode width. We will present a comprehensive overview of the impact of each varied parameter on the DSSD performance, in view of the application to PACT. The considered DSSD parameters are its depletion voltage, capacitance, and leakage current. After the selection of the PACT DSSD, we will present a simulation of the performance of the PACT telescope in the 0.1-10 MeV range.

Thick silicon microstrip detectors simulation for PACT: Pair and Compton Telescope

International Nuclear Information System (INIS)

Khalil, M.; Laurent, P.; Lebrun, F.; Tatischeff, V.; Dolgorouky, Y.; Bertoli, W.; Breelle, E.

2016-01-01

PACT is a space borne Pair and Compton Telescope that aims to make a sensitive survey of the gamma-ray sky between 100 keV and 100 MeV. It is based upon two main components: a silicon-based gamma-ray tracker and a crystal-based calorimeter. In this paper we will explain the imaging technique of PACT as a Multi-layered Compton telescope (0.1–10 MeV) and its major improvements over its predecessor COMPTEL. Then we will present a simulation study to optimize the silicon tracker of PACT. This tracker is formed of thousands of identical silicon double sided strip detectors (DSSDs). We have developed a simulation model (using SILVACO) to simulate the DSSD performance while varying its thickness, impurity concentration of the bulk material, electrode pitch, and electrode width. We will present a comprehensive overview of the impact of each varied parameter on the DSSD performance, in view of the application to PACT. The considered DSSD parameters are its depletion voltage, capacitance, and leakage current. After the selection of the PACT DSSD, we will present a simulation of the performance of the PACT telescope in the 0.1–10 MeV range.

Thick silicon microstrip detectors simulation for PACT: Pair and Compton Telescope

Energy Technology Data Exchange (ETDEWEB)

Khalil, M., E-mail: khalilmohammad@hotmail.com [APC Laboratory, 10rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France); Laurent, P.; Lebrun, F. [APC Laboratory, 10rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France); CEA, Centre de Saclay, 91191 Gif-Sur-Yvette Cedex (France); Tatischeff, V. [CSNSM, IN2P3/CNRSand Paris-Sud University, 91405 Orsay Campus (France); Dolgorouky, Y.; Bertoli, W.; Breelle, E. [APC Laboratory, 10rue Alice Domon et Léonie Duquet, 75205 Paris Cedex 13 (France)

2016-11-01

PACT is a space borne Pair and Compton Telescope that aims to make a sensitive survey of the gamma-ray sky between 100 keV and 100 MeV. It is based upon two main components: a silicon-based gamma-ray tracker and a crystal-based calorimeter. In this paper we will explain the imaging technique of PACT as a Multi-layered Compton telescope (0.1–10 MeV) and its major improvements over its predecessor COMPTEL. Then we will present a simulation study to optimize the silicon tracker of PACT. This tracker is formed of thousands of identical silicon double sided strip detectors (DSSDs). We have developed a simulation model (using SILVACO) to simulate the DSSD performance while varying its thickness, impurity concentration of the bulk material, electrode pitch, and electrode width. We will present a comprehensive overview of the impact of each varied parameter on the DSSD performance, in view of the application to PACT. The considered DSSD parameters are its depletion voltage, capacitance, and leakage current. After the selection of the PACT DSSD, we will present a simulation of the performance of the PACT telescope in the 0.1–10 MeV range.

Virtual design and optimization studies for industrial silicon microphones applying tailored system-level modeling

Science.gov (United States)

Kuenzig, Thomas; Dehé, Alfons; Krumbein, Ulrich; Schrag, Gabriele

2018-05-01

Maxing out the technological limits in order to satisfy the customers’ demands and obtain the best performance of micro-devices and-systems is a challenge of today’s manufacturers. Dedicated system simulation is key to investigate the potential of device and system concepts in order to identify the best design w.r.t. the given requirements. We present a tailored, physics-based system-level modeling approach combining lumped with distributed models that provides detailed insight into the device and system operation at low computational expense. The resulting transparent, scalable (i.e. reusable) and modularly composed models explicitly contain the physical dependency on all relevant parameters, thus being well suited for dedicated investigation and optimization of MEMS devices and systems. This is demonstrated for an industrial capacitive silicon microphone. The performance of such microphones is determined by distributed effects like viscous damping and inhomogeneous capacitance variation across the membrane as well as by system-level phenomena like package-induced acoustic effects and the impact of the electronic circuitry for biasing and read-out. The here presented model covers all relevant figures of merit and, thus, enables to evaluate the optimization potential of silicon microphones towards high fidelity applications. This work was carried out at the Technical University of Munich, Chair for Physics of Electrotechnology. Thomas Kuenzig is now with Infineon Technologies AG, Neubiberg.

Effect of oxygen and hydrogen on the optical and electrical characteristics of porous silicon. Towards sensor applications

International Nuclear Information System (INIS)

Green, S.

2000-02-01

, which was found to be 3x10 18 cm -3 eV -1 . The often-reported high ideality factors (i.e. a value greater than one) for metal-porous silicon junctions have been interpreted in terms of the high defect density in porous silicon. Transverse impedance measurements (viz.: parallel capacitance and conductance) on exposure to hydrogen show a strong dependency upon the applied frequency and bias. Capacitance of a Au/PS/p-Si/Al..Ag device only shows a response to hydrogen in two frequency windows 100 Hz 2 - ions on the porous silicon surface. (author)

Silicon based nanogap device for studying electrical transport phenomena in molecule-nanoparticle hybrids

International Nuclear Information System (INIS)

Strobel, Sebastian; Hernandez, Rocio Murcia; Hansen, Allan G; Tornow, Marc

2008-01-01

We report the fabrication and characterization of vertical nanogap electrode devices using silicon-on-insulator substrates. Using only standard silicon microelectronic process technology, nanogaps down to 26 nm electrode separation were prepared. Transmission electron microscopy cross-sectional analysis revealed the well defined material architecture of the nanogap, comprising two electrodes of dissimilar geometrical shape. This asymmetry is directly reflected in transport measurements on molecule-nanoparticle hybrid systems formed by self-assembling a monolayer of mercaptohexanol on the electrode surface and the subsequent dielectrophoretic trapping of 30 nm diameter Au nanoparticles. The observed Coulomb staircase I-V characteristic measured at T = 4.2 K is in excellent agreement with theoretical modelling, whereby junction capacitances of the order of a few 10 -18 farad and asymmetric resistances of 30 and 300 MΩ, respectively, are also supported well by our independent estimates for the formed double barrier tunnelling system. We propose our nanoelectrode system for integrating novel functional electronic devices such as molecular junctions or nanoparticle hybrids into existing silicon microelectronic process technology

Silicon based nanogap device for studying electrical transport phenomena in molecule-nanoparticle hybrids

Energy Technology Data Exchange (ETDEWEB)

Strobel, Sebastian; Hernandez, Rocio Murcia [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall 3, 85748 Garching (Germany); Hansen, Allan G; Tornow, Marc [Institut fuer Halbleitertechnik, Technische Universitaet Braunschweig, Hans-Sommer-Strasse 66, 38106 Braunschweig (Germany)], E-mail: m.tornow@tu-bs.de

2008-09-17

We report the fabrication and characterization of vertical nanogap electrode devices using silicon-on-insulator substrates. Using only standard silicon microelectronic process technology, nanogaps down to 26 nm electrode separation were prepared. Transmission electron microscopy cross-sectional analysis revealed the well defined material architecture of the nanogap, comprising two electrodes of dissimilar geometrical shape. This asymmetry is directly reflected in transport measurements on molecule-nanoparticle hybrid systems formed by self-assembling a monolayer of mercaptohexanol on the electrode surface and the subsequent dielectrophoretic trapping of 30 nm diameter Au nanoparticles. The observed Coulomb staircase I-V characteristic measured at T = 4.2 K is in excellent agreement with theoretical modelling, whereby junction capacitances of the order of a few 10{sup -18} farad and asymmetric resistances of 30 and 300 M{omega}, respectively, are also supported well by our independent estimates for the formed double barrier tunnelling system. We propose our nanoelectrode system for integrating novel functional electronic devices such as molecular junctions or nanoparticle hybrids into existing silicon microelectronic process technology.

Silicon based nanogap device for studying electrical transport phenomena in molecule-nanoparticle hybrids.

Science.gov (United States)

Strobel, Sebastian; Hernández, Rocío Murcia; Hansen, Allan G; Tornow, Marc

2008-09-17

We report the fabrication and characterization of vertical nanogap electrode devices using silicon-on-insulator substrates. Using only standard silicon microelectronic process technology, nanogaps down to 26 nm electrode separation were prepared. Transmission electron microscopy cross-sectional analysis revealed the well defined material architecture of the nanogap, comprising two electrodes of dissimilar geometrical shape. This asymmetry is directly reflected in transport measurements on molecule-nanoparticle hybrid systems formed by self-assembling a monolayer of mercaptohexanol on the electrode surface and the subsequent dielectrophoretic trapping of 30 nm diameter Au nanoparticles. The observed Coulomb staircase I-V characteristic measured at T = 4.2 K is in excellent agreement with theoretical modelling, whereby junction capacitances of the order of a few 10(-18) farad and asymmetric resistances of 30 and 300 MΩ, respectively, are also supported well by our independent estimates for the formed double barrier tunnelling system. We propose our nanoelectrode system for integrating novel functional electronic devices such as molecular junctions or nanoparticle hybrids into existing silicon microelectronic process technology.

Design of an ultra-low-power digital processor for passive UHF RFID tags

International Nuclear Information System (INIS)

Shi Wanggen; Zhuang Yiqi; Li Xiaoming; Wang Xianghua; Jin Zhao; Wang Dan

2009-01-01

A new architecture of digital processors for passive UHF radio-frequency identification tags is proposed. This architecture is based on ISO/IEC 18000-6C and targeted at ultra-low power consumption. By applying methods like system-level power management, global clock gating and low voltage implementation, the total power of the design is reduced to a few microwatts. In addition, an innovative way for the design of a true RNG is presented, which contributes to both low power and secure data transaction. The digital processor is verified by an integrated FPGA platform and implemented by the Synopsys design kit for ASIC flows. The design fits different CMOS technologies and has been taped out using the 2P4M 0.35 μm process of Chartered Semiconductor.

Small Size and Low Cost UHF RFID Tag Antenna Mountable on Metallic Objects

Directory of Open Access Journals (Sweden)

Sergio López-Soriano

2015-01-01

Full Text Available Reducing tag size while maintaining good performance is one of the major challenges in radio-frequency identification applications (RFID, in particular when labeling metallic objects. In this contribution, a small size and low cost tag antenna for identifying metal objects in the European UHF band (865–868 MHz is presented. The antenna consists of a transmission line mounted on an inexpensive thin dielectric which is proximity-coupled to a short-ended patch mounted on FR4 substrate. The overall dimensions of the tag are 33.5 × 30 × 3.1 mm. Experimental results show that, for an EIRP of 3.2 W (European regulations, such a small and cheap tag attains read ranges of about 5 m when attached to a metallic object.

The split delivery capacitated team orienteering problem

NARCIS (Netherlands)

Archetti, C.; Bianchessi, N.; Speranza, M. G.; Hertz, A.

2014-01-01

In this article, we study the capacitated team orienteering problem where split deliveries are allowed. A set of potential customers is given, each associated with a demand and a profit. The set of customers to be served by a fleet of capacitated vehicles has to be identified in such a way that the

Low surface damage dry etched black silicon

Science.gov (United States)

Plakhotnyuk, Maksym M.; Gaudig, Maria; Davidsen, Rasmus Schmidt; Lindhard, Jonas Michael; Hirsch, Jens; Lausch, Dominik; Schmidt, Michael Stenbæk; Stamate, Eugen; Hansen, Ole

2017-10-01

Black silicon (bSi) is promising for integration into silicon solar cell fabrication flow due to its excellent light trapping and low reflectance, and a continuously improving passivation. However, intensive ion bombardment during the reactive ion etching used to fabricate bSi induces surface damage that causes significant recombination. Here, we present a process optimization strategy for bSi, where surface damage is reduced and surface passivation is improved while excellent light trapping and low reflectance are maintained. We demonstrate that reduction of the capacitively coupled plasma power, during reactive ion etching at non-cryogenic temperature (-20 °C), preserves the reflectivity below 1% and improves the effective minority carrier lifetime due to reduced ion energy. We investigate the effect of the etching process on the surface morphology, light trapping, reflectance, transmittance, and effective lifetime of bSi. Additional surface passivation using atomic layer deposition of Al2O3 significantly improves the effective lifetime. For n-type wafers, the lifetime reaches 12 ms for polished and 7.5 ms for bSi surfaces. For p-type wafers, the lifetime reaches 800 μs for both polished and bSi surfaces.

INFLUENCE OF ELECTROPOLYMERIZATION METHOD ON MORPHOLOGIES AND CAPACITIVE PROPERTIES OF POLYPYRROLE FILMS GROWING ON SILICON

OpenAIRE

IMENE CHIKOUCHE; ALI SAHARI; AHMED ZOUAOUI

2014-01-01

Two methods of Pyrrole electropolymerization were investigated to prepare polypyrrole films growing onto n-doped silicon n-Si (111): Polypyrrole films prepared by galvanostatic method exhibits toroidal morphology for thin films, and mixture of toroidal and globular morphologies for thick films. Polypyrrole films obtained from this method were characterized by lower surface roughness. Electropolymerization of pyrrole by potentiodynamic method provided Polypyrrole films with beans-like structur...

Percoll gradient-centrifuged capacitated mouse sperm have increased fertilizing ability and higher contents of sulfogalactosylglycerolipid and docosahexaenoic acid-containing phosphatidylcholine compared to washed capacitated mouse sperm.

Science.gov (United States)

Furimsky, Anna; Vuong, Ngoc; Xu, Hongbin; Kumarathasan, Premkumari; Xu, Min; Weerachatyanukul, Wattana; Bou Khalil, Maroun; Kates, Morris; Tanphaichitr, Nongnuj

2005-03-01

Although Percoll gradient centrifugation has been used routinely to prepare motile human sperm, its use in preparing motile mouse sperm has been limited. Here, we showed that Percoll gradient-centrifuged (PGC) capacitated mouse sperm had markedly higher fertilizing ability (sperm-zona pellucida [ZP] binding and in vitro fertilization) than washed capacitated mouse sperm. We also showed that the lipid profiles of PGC capacitated sperm and washed capacitated sperm differed significantly. The PGC sperm had much lower contents of cholesterol and phospholipids. This resulted in relative enrichment of male germ cell-specific sulfogalactosylglycerolipid (SGG), a ZP-binding ligand, in PGC capacitated sperm, and this would explain, in part, their increased ZP-binding ability compared with that of washed capacitated sperm. Analyses of phospholipid fatty acyl chains revealed that PGC capacitated sperm were enriched in phosphatidylcholine (PC) molecular species containing highly unsaturated fatty acids (HUFAs), with docosahexaenoic acid (DHA; C22: 6n-3) being the predominant HUFA (42% of total hydrocarbon chains of PC). In contrast, the level of PC-HUFAs comprising arachidonic acid (20:4n-6), docosapentaenoic acid (C22:5n-6), and DHA in washed capacitated sperm was only 27%. Having the highest unsaturation degree among all HUFAs in PC, DHA would enhance membrane fluidity to the uppermost. Therefore, membranes of PGC capacitated sperm would undergo fertilization-related fusion events at higher rates than washed capacitated sperm. These results suggested that PGC mouse sperm should be used in fertilization experiments and that SGG and DHA should be considered to be important biomarkers for sperm fertilizing ability.

Limitations on energy resolution of segmented silicon detectors

Science.gov (United States)

Wiącek, P.; Chudyba, M.; Fiutowski, T.; Dąbrowski, W.

2018-04-01

In the paper experimental study of charge division effects and energy resolution of X-ray silicon pad detectors are presented. The measurements of electrical parameters, capacitances and leakage currents, for six different layouts of pad arrays are reported. The X-ray spectra have been measured using a custom developed dedicated low noise front-end electronics. The spectra measured for six different detector layouts have been analysed in detail with particular emphasis on quantitative evaluation of charge division effects. Main components of the energy resolution due to Fano fluctuations, electronic noise, and charge division, have been estimated for six different sensor layouts. General recommendations regarding optimisation of pad sensor layout for achieving best possible energy resolution have been formulated.

New developments in double sided silicon strip detectors

International Nuclear Information System (INIS)

Becker, H.; Boulos, T.; Cattaneo, P.; Dietl, H.; Hauff, D.; Holl, P.; Lange, E.; Lutz, G.; Moser, H.G.; Schwarz, A.S.; Settles, R.; Struder, L.; Kemmer, J.; Buttler, W.

1990-01-01

A new type of double sided silicon strip detector has been built and tested using highly density VLSI readout electronics connected to both sides. Capacitive coupling of the strips to the readout electronics has been achieved by integrating the capacitors into the detector design, which was made possible by introducing a new detector biasing concept. Schemes to simplify the technology of the fabrication of the detectors are discussed. The static performance properties of the devices as well as implications of the use of VLSI electronics in their readout are described. Prototype detectors of the described design equipped with high density readout electronics have been installed in the ALEPH detector at LEP. Test results on the performance are given

Electrochemical capacitance performance of titanium nitride nanoarray

Energy Technology Data Exchange (ETDEWEB)

Xie, Yibing, E-mail: ybxie@seu.edu.cn [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Suzhou Research Institute of Southeast University, Suzhou 215123 (China); Wang, Yong [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Du, Hongxiu [School of Chemistry and Chemical Engineering, Southeast University, Nanjing 211189 (China); Suzhou Research Institute of Southeast University, Suzhou 215123 (China)

2013-12-01

Highlights: • TiN nanoarray is formed by a nitridation process of TiO{sub 2} in ammonia atmosphere. • TiN nanoarray exhibits much higher EDLC capacitance than TiO{sub 2} nanoarray. • The specific capacitance of TiN nanoarray achieves a high level of 99.7 mF cm{sup −2}. • A flexible solid-state supercapacitor is constructed by TiN nanoarray and PVA gel. -- Abstract: In this study, titanium nitride (TiN) nanoarrays with a short nanotube and long nanopore structure have been prepared by an anodization process of ultra thin titanium foil in ethylene glycol (EG) solution containing ammonium fluoride, subsequent calcination process in an air atmosphere, and final nitridation process in an ammonia atmosphere. The morphology and microstructure characterization has been conducted using field emission scanning electron microscope and X-ray diffraction. The electrochemical properties have been investigated through cyclic voltammetry and electrochemical impedance spectrum measurements. The electrochemical capacitance performance has been investigated by galvanostatic charge–discharge measurements in the acidic, neural and alkali electrolyte solution. Well-defined TiN nanoarrays contribute a much higher capacitance performance than titania (TiO{sub 2}) in the supercapacitor application due to the extraordinarily improved electrical conductivity. Such an electrochemical capacitance can be further enhanced by increasing aspect ratio of TiN nanoarray from short nanotubes to long nanopores. A flexible supercapacitor has been constructed using two symmetrical TiN nanoarray electrodes and a polyvinyl alcohol (PVA) gel electrolyte with H{sub 2}SO{sub 4}–KCl–H{sub 2}O–EG. Such a supercapacitor has a highly improved potential window and still keeps good electrochemical energy storage. TiN nanoarray with a high aspect ratio can act well as an ultra thin film electrode material of flexible supercapacitor to contribute a superior capacitance performance.

Can root electrical capacitance be used to predict root mass in soil?

Science.gov (United States)

Dietrich, R C; Bengough, A G; Jones, H G; White, P J

2013-07-01

Electrical capacitance, measured between an electrode inserted at the base of a plant and an electrode in the rooting substrate, is often linearly correlated with root mass. Electrical capacitance has often been used as an assay for root mass, and is conventionally interpreted using an electrical model in which roots behave as cylindrical capacitors wired in parallel. Recent experiments in hydroponics show that this interpretation is incorrect and a new model has been proposed. Here, the new model is tested in solid substrates. The capacitances of compost and soil were determined as a function of water content, and the capacitances of cereal plants growing in sand or potting compost in the glasshouse, or in the field, were measured under contrasting irrigation regimes. Capacitances of compost and soil increased with increasing water content. At water contents approaching field capacity, compost and soil had capacitances at least an order of magnitude greater than those of plant tissues. For plants growing in solid substrates, wetting the substrate locally around the stem base was both necessary and sufficient to record maximum capacitance, which was correlated with stem cross-sectional area: capacitance of excised stem tissue equalled that of the plant in wet soil. Capacitance measured between two electrodes could be modelled as an electrical circuit in which component capacitors (plant tissue or rooting substrate) are wired in series. The results were consistent with the new physical interpretation of plant capacitance. Substrate capacitance and plant capacitance combine according to standard physical laws. For plants growing in wet substrate, the capacitance measured is largely determined by the tissue between the surface of the substrate and the electrode attached to the plant. Whilst the measured capacitance can, in some circumstances, be correlated with root mass, it is not a direct assay of root mass.

Qualitative doping area characterization of SONOS transistor utilizing scanning capacitance microscopy (SCM) and scanning spread resistance microscopy (SSRM)

International Nuclear Information System (INIS)

Heo, Jinhee; Kim, Deoksu; Kim, Chung woo; Chung, Ilsub

2005-01-01

Continuous shrinkage in the memory devices demands further understanding about the doping concentration variations at shallow junction and channel region. Scanning capacitance microscopy (SCM) and scanning spread resistance microscopy (SSRM) can provide reliable information about the electrical and physical junction structure simultaneously. In this work, we attempt to visualize the doping concentration variations of split-gate structure silicon-oxide-nitride-oxide-silicon (SONOS) transistor with thin oxide-nitride-oxide (ONO; 4/7/11 nm). From SCM image, we could identify the source and drain region, which have different doping concentrations from that at channel region. In addition, a gate oxide layer and a depletion region were also identified. Similar results were obtained using SSRM. However, SSRM shows a better resolution, in particular, for highly doped region. For this experiment, the cross-sectional sample has been prepared using focused ion beam (FIB) and hand-polishing method. The results show that SCM and SSRM are very useful methods to analyze the doping profile near the junction as well as the channel

Carbon nanofiber supercapacitors with large areal capacitances

KAUST Repository

McDonough, James R.

2009-01-01

We develop supercapacitor (SC) devices with large per-area capacitances by utilizing three-dimensional (3D) porous substrates. Carbon nanofibers (CNFs) functioning as active SC electrodes are grown on 3D nickel foam. The 3D porous substrates facilitate a mass loading of active electrodes and per-area capacitance as large as 60 mg/ cm2 and 1.2 F/ cm2, respectively. We optimize SC performance by developing an annealing-free CNF growth process that minimizes undesirable nickel carbide formation. Superior per-area capacitances described here suggest that 3D porous substrates are useful in various energy storage devices in which per-area performance is critical. © 2009 American Institute of Physics.

\\title{Development of Radiation Damage Models for Irradiated Silicon Sensors Using TCAD Tools}

CERN Document Server

Bhardwaj, Ashutosh; Lalwani, Kavita; Ranjan, Kirti; Printz, Martin; Ranjeet, Ranjeet; Eber, Robert; Eichhorn, Thomas; Peltola, Timo Hannu Tapani

2014-01-01

Abstract. During the high luminosity upgrade of the LHC (HL-LHC) the CMS tracking system will face a more intense radiation environment than the present system was designed for. In order to design radiation tolerant silicon sensors for the future CMS tracker upgrade it is fundamental to complement the measurement with device simulation. This will help in both the understanding of the device performance and in the optimization of the design parameters. One of the important ingredients of the device simulation is to develop a radiation damage model incorporating both bulk and surface damage. In this paper we will discuss the development of a radiation damage model by using commercial TCAD packages (Silvaco and Synopsys), which successfully reproduce the recent measurements like leakage current, depletion voltage, interstrip capacitance and interstrip resistance, and provides an insight into the performance of irradiated silicon strip sensors.

Capacitive behavior of highly-oxidized graphite

Science.gov (United States)

Ciszewski, Mateusz; Mianowski, Andrzej

2014-09-01

Capacitive behavior of a highly-oxidized graphite is presented in this paper. The graphite oxide was synthesized using an oxidizing mixture of potassium chlorate and concentrated fuming nitric acid. As-oxidized graphite was quantitatively and qualitatively analyzed with respect to the oxygen content and the species of oxygen-containing groups. Electrochemical measurements were performed in a two-electrode symmetric cell using KOH electrolyte. It was shown that prolonged oxidation causes an increase in the oxygen content while the interlayer distance remains constant. Specific capacitance increased with oxygen content in the electrode as a result of pseudo-capacitive effects, from 0.47 to 0.54 F/g for a scan rate of 20 mV/s and 0.67 to 1.15 F/g for a scan rate of 5 mV/s. Better cyclability was observed for the electrode with a higher oxygen amount.

High-k materials in the electrolyte/insulator/silicon configuration. Characterization and application in bio-electronics; Hoch-k-Materialien in der Elektrolyt/Isolator/Silizium-Konfiguration. Charakterisierung und Anwendung in der Bioelektronik

Energy Technology Data Exchange (ETDEWEB)

Wallrapp, F

2006-12-19

In order to elicit action potentials in nerve cells adhered on electrodes, a certain current is required across the electrode. Electrochemical reactions may cause damage to cells and electrodes. This is evaded by using silicon electrodes which are insulated by a dielectric. In doing so, only capacitive current is flowing, and electrochemical are avoided. The aim of this work was to fabricate novel stimulation chips exhibiting an enhanced capacitance which render new biological applications possible. These chips were to be characterized and used for the stimulation of cells. The formerly used dielectric SiO{sub 2} was replaced by HfO{sub 2} and TiO{sub 2}, with both of them featuring a higher dielectric constant. They were deposited on the silicon substrate by ALD (atomic layer deposition). The chips were characterized in the electrolyte/insulator/semiconductor (EIS) configuration. Owing to the low leakage current of the EIS configuration, the characterization of the high-k materials was possible in more detail as compared to using a metallic top contact (MIS configuration). The voltage-dependent capacitances of the HfO{sub 2} films could be interpreted by means of a common metal/SiO{sub 2}/silicon system. In contrast, the TiO{sub 2} films exhibited interesting properties which could only be rationalized with the help of numerical calculations assuming free electrons in the TiO{sub 2}. The low-lying conduction band of TiO{sub 2} caused accumulation of electrons within the TiO{sub 2} for certain voltages, which led to an enhanced capacitance. The effects of high voltages, frequency, film thickness and interlayer composition were examined and brought into compliance with the model. The novel TiO{sub 2} stimulation devices featured a five-fold capacitance increase as compared to former SiO{sub 2} chips. Using them, two fundamental stimulation mechanisms were induced in HEK293 cells expressing the recombinant potassium channel Kv1.3: Opening of ion channels and

Carrier Statistics and Quantum Capacitance Models of Graphene Nanoscroll

Directory of Open Access Journals (Sweden)

M. Khaledian

2014-01-01

schematic perfect scroll-like Archimedes spiral. The DOS model was derived at first, while it was later applied to compute the carrier concentration and quantum capacitance model. Furthermore, the carrier concentration and quantum capacitance were modeled for both degenerate and nondegenerate regimes, along with examining the effect of structural parameters and chirality number on the density of state and carrier concentration. Latterly, the temperature effect on the quantum capacitance was studied too.

Programmable differential capacitance-to-voltage converter for MEMS accelerometers

Science.gov (United States)

Royo, G.; Sánchez-Azqueta, C.; Gimeno, C.; Aldea, C.; Celma, S.

2017-05-01

Capacitive MEMS sensors exhibit an excellent noise performance, high sensitivity and low power consumption. They offer a huge range of applications, being the accelerometer one of its main uses. In this work, we present the design of a capacitance-to-voltage converter in CMOS technology to measure the acceleration from the capacitance variations. It is based on a low-power, fully-differential transimpedance amplifier with low input impedance and a very low input noise.

Human body capacitance: static or dynamic concept? [ESD

DEFF Research Database (Denmark)

Jonassen, Niels M

1998-01-01

A standing human body insulated from ground by footwear and/or floor covering is in principle an insulated conductor and has, as such, a capacitance, i.e. the ability to store a charge and possibly discharge the stored energy in a spark discharge. In the human body, the human body capacitance (HBC...... when a substantial part of the flux extends itself through badly defined stray fields. Since the concept of human body capacitance is normally used in a static (electric) context, it is suggested that the HBC be determined by a static method. No theoretical explanation of the observed differences...

A bipolar analog front-end integrated circuit for the SDC silicon tracker

International Nuclear Information System (INIS)

Kipnis, I.; Spieler, H.; Collins, T.

1993-11-01

A low-noise, low-power, high-bandwidth, radiation hard, silicon bipolar-transistor full-custom integrated circuit (IC) containing 64 channels of analog signal processing has been developed for the SDC silicon tracker. The IC was designed and tested at LBL and was fabricated using AT ampersand T's CBIC-U2, 4 GHz f T complementary bipolar technology. Each channel contains the following functions: low-noise preamplification, pulse shaping and threshold discrimination. This is the first iteration of the production analog IC for the SDC silicon tracker. The IC is laid out to directly match the 50 μm pitch double-sided silicon strip detector. The chip measures 6.8 mm x 3.1 mm and contains 3,600 transistors. Three stages of amplification provide 180 mV/fC of gain with a 35 nsec peaking time at the comparator input. For a 14 pF detector capacitance, the equivalent noise charge is 1300 el. rms at a power consumption of 1 mW/channel from a single 3.5 V supply. With the discriminator threshold set to 4 times the noise level, a 16 nsec time-walk for 1.25 to 10fC signals is achieved using a time-walk compensation network. Irradiation tests at TRIUMF to a Φ=10 14 protons/cm 2 have been performed on the IC, demonstrating the radiation hardness of the complementary bipolar process

Carrier accumulation and depletion in point-contact capacitance-voltage measurements

Science.gov (United States)

Naitou, Yuichi

2017-11-01

Scanning capacitance microscopy (SCM) is a variation of atomic force microscopy in which a conductive probe tip detects the bias modulated capacitance for the purpose of measuring the nanoscale semiconductor carrier concentration. SCM can be regarded as a point-contact capacitance-voltage system, and its capacitance-voltage properties are different from those of a conventional parallel-plate capacitor. In this study, the charge accumulation and depletion behavior of a semiconductor sample were closely investigated by SCM. By analyzing the tip-sample approach curve, the effective probe tip area and charge depletion depth could be quantitatively determined.

Capacitance-based frequency adjustment of micro piezoelectric vibration generator.

Science.gov (United States)

Mao, Xinhua; He, Qing; Li, Hong; Chu, Dongliang

2014-01-01

Micro piezoelectric vibration generator has a wide application in the field of microelectronics. Its natural frequency is unchanged after being manufactured. However, resonance cannot occur when the natural frequencies of a piezoelectric generator and the source of vibration frequency are not consistent. Output voltage of the piezoelectric generator will sharply decline. It cannot normally supply power for electronic devices. In order to make the natural frequency of the generator approach the frequency of vibration source, the capacitance FM technology is adopted in this paper. Different capacitance FM schemes are designed by different locations of the adjustment layer. The corresponding capacitance FM models have been established. Characteristic and effect of the capacitance FM have been simulated by the FM model. Experimental results show that the natural frequency of the generator could vary from 46.5 Hz to 42.4 Hz when the bypass capacitance value increases from 0 nF to 30 nF. The natural frequency of a piezoelectric vibration generator could be continuously adjusted by this method.

Capacitance-Based Frequency Adjustment of Micro Piezoelectric Vibration Generator

Directory of Open Access Journals (Sweden)

Xinhua Mao

2014-01-01

Full Text Available Micro piezoelectric vibration generator has a wide application in the field of microelectronics. Its natural frequency is unchanged after being manufactured. However, resonance cannot occur when the natural frequencies of a piezoelectric generator and the source of vibration frequency are not consistent. Output voltage of the piezoelectric generator will sharply decline. It cannot normally supply power for electronic devices. In order to make the natural frequency of the generator approach the frequency of vibration source, the capacitance FM technology is adopted in this paper. Different capacitance FM schemes are designed by different locations of the adjustment layer. The corresponding capacitance FM models have been established. Characteristic and effect of the capacitance FM have been simulated by the FM model. Experimental results show that the natural frequency of the generator could vary from 46.5 Hz to 42.4 Hz when the bypass capacitance value increases from 0 nF to 30 nF. The natural frequency of a piezoelectric vibration generator could be continuously adjusted by this method.

A low cost integrated transceiver for mobile UHF passive RFID reader applications

Energy Technology Data Exchange (ETDEWEB)

Wang Jingchao; Zhang Chun; Chi Baoyong; Wang Ziqiang; Li Fule; Wang Zhihua, E-mail: wangjc@gmail.co [Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

2009-09-15

A low cost integrated transceiver for mobile UHF passive RFID reader applications is implemented in a 0.18-{mu}m CMOS process. The transceiver contains an OOK modulator and a power amplifier in the transmitter chain, an IQ direct-down converter, variable-gain amplifiers, channel-select filters and a 10-bit ADC in the receiver chain. The measured output P{sub 1DB} power of the transmitter is 17.6 dBm and the measured receiver sensitivity is -70 dBm. The on-chip integer N synthesizer achieves a frequency resolution of 200 kHz with a phase noise of -104 dBc/Hz at 100 kHz frequency offset and -120.83 dBc/Hz at 1 MHz frequency offset. The transmitter, the receiver and the frequency synthesizer consume 201.34, 25.3 and 54 mW, respectively. The chip has a die area of 4 x 2.5 mm{sup 2} including pads.

A low cost integrated transceiver for mobile UHF passive RFID reader applications

International Nuclear Information System (INIS)

Wang Jingchao; Zhang Chun; Chi Baoyong; Wang Ziqiang; Li Fule; Wang Zhihua

2009-01-01

A low cost integrated transceiver for mobile UHF passive RFID reader applications is implemented in a 0.18-μm CMOS process. The transceiver contains an OOK modulator and a power amplifier in the transmitter chain, an IQ direct-down converter, variable-gain amplifiers, channel-select filters and a 10-bit ADC in the receiver chain. The measured output P 1DB power of the transmitter is 17.6 dBm and the measured receiver sensitivity is -70 dBm. The on-chip integer N synthesizer achieves a frequency resolution of 200 kHz with a phase noise of -104 dBc/Hz at 100 kHz frequency offset and -120.83 dBc/Hz at 1 MHz frequency offset. The transmitter, the receiver and the frequency synthesizer consume 201.34, 25.3 and 54 mW, respectively. The chip has a die area of 4 x 2.5 mm 2 including pads.

Design and implementation of an ultra-low power passive UHF RFID tag

International Nuclear Information System (INIS)

Shen Jinpeng; Wang Xin'an; Liu Shan; Zong Hongqiang; Huang Jinfeng; Yang Xin; Feng Xiaoxing; Ge Binjie

2012-01-01

This paper presents a fully integrated passive UHF RFID tag chip complying with the ISO18000-6B protocol. The tag chip includes an RF/analog front-end, a baseband processor, and a 512-bit EEPROM memory. To improve power conversion efficiency, a Schottky barrier diode based rectifier is adopted. A novel voltage reference using the peaking current source is discussed in detail, which can meet the low-power, low-voltage requirement while retaining circuit simplicity. Most of the analog blocks are designed to work under sub-1 V to reduce power consumption, and several practical methods are used to further reduce the power consumption of the baseband processor. The whole tag chip is implemented in a TSMC 0.18 μm CMOS process with a die size of 800 × 800 μm 2 . Measurement results show that the total power consumption of the tag chip is only 7.4 μW with a sensitivity of −12 dBm. (semiconductor integrated circuits)

Impact of the silicon substrate resistivity and growth condition on the deep levels in Ni-Au/AlN/Si MIS Capacitors

Science.gov (United States)

Wang, Chong; Simoen, Eddy; Zhao, Ming; Li, Wei

2017-10-01

Deep levels formed under different growth conditions of a 200 nm AlN buffer layer on B-doped Czochralski Si(111) substrates with different resistivity were investigated by deep-level transient spectroscopy (DLTS) on metal-insulator-semiconductor capacitors. Growth-temperature-dependent Al diffusion in the Si substrate was derived from the free carrier density obtained by capacitance-voltage measurement on samples grown on p- substrates. The DLTS spectra revealed a high concentration of point and extended defects in the p- and p+ silicon substrates, respectively. This indicated a difference in the electrically active defects in the silicon substrate close to the AlN/Si interface, depending on the B doping concentration.

A highly sensitive and durable electrical sensor for liquid ethanol using thermally-oxidized mesoporous silicon

Science.gov (United States)

Harraz, Farid A.; Ismail, Adel A.; Al-Sayari, S. A.; Al-Hajry, A.; Al-Assiri, M. S.

2016-12-01

A capacitive detection of liquid ethanol using reactive, thermally oxidized films constructed from electrochemically synthesized porous silicon (PSi) is demonstrated. The sensor elements are fabricated as meso-PSi (pore sizes hydrophobic PSi surface exhibited almost a half sensitivity of the thermal oxide sensor. The response to water is achieved only at the oxidized surface and found to be ∼one quarter of the ethanol sensitivity, dependent on parameters such as vapor pressure and surface tension. The capacitance response retains ∼92% of its initial value after continuous nine cyclic runs and the sensors presumably keep long-term stability after three weeks storage, demonstrating excellent durability and storage stability. The observed behavior in current system is likely explained by the interface interaction due to dipole moment effect. The results suggest that the current sensor structure and design can be easily made to produce notably higher sensitivities for reversible detection of various analytes.

Passive UHF RFID Tags with Specific Printed Antennas for Dielectric and Metallic Objects Applications

Directory of Open Access Journals (Sweden)

K. Siakavara

2017-09-01

Full Text Available Design process and respective results for the synthesis of specific Radiofrequency Identification(RFID tag antennas, suitable for dielectric and metallic objects, are presented. The antennas were designed for the UHF(865MHz-869MHz band and their basic configuration is that of the printed spiral type. Six modification steps to the classical spiral layout are proposed and it was proved that they can lead to tags with high readability and reading distances up to 10m when designed for dielectric object and up to 7m in the case of metallic objects. The results of the measurements of the fabricated tags are explained via theoretical evaluations which take into account reflection phenomena, that are present in a real environment at which the tags are used.

CMOS Silicon-on-Sapphire RF Tunable Matching Networks

Directory of Open Access Journals (Sweden)

Chamseddine Ahmad

2006-01-01

Full Text Available This paper describes the design and optimization of an RF tunable network capable of matching highly mismatched loads to 50 at 1.9 GHz. Tuning was achieved using switched capacitors with low-loss, single-transistor switches. Simulations show that the performance of the matching network depends strongly on the switch performances and on the inductor losses. A 0.5 m silicon-on-sapphire (SOS CMOS technology was chosen for network implementation because of the relatively high-quality monolithic inductors achievable in the process. The matching network provides very good matching for inductive loads, and acceptable matching for highly capacitive loads. A 1 dB compression point greater than dBm was obtained for a wide range of load impedances.

Isolating and moving single atoms using silicon nanocrystals

Science.gov (United States)

Carroll, Malcolm S.

2010-09-07

A method is disclosed for isolating single atoms of an atomic species of interest by locating the atoms within silicon nanocrystals. This can be done by implanting, on the average, a single atom of the atomic species of interest into each nanocrystal, and then measuring an electrical charge distribution on the nanocrystals with scanning capacitance microscopy (SCM) or electrostatic force microscopy (EFM) to identify and select those nanocrystals having exactly one atom of the atomic species of interest therein. The nanocrystals with the single atom of the atomic species of interest therein can be sorted and moved using an atomic force microscope (AFM) tip. The method is useful for forming nanoscale electronic and optical devices including quantum computers and single-photon light sources.

The capacitated team orienteering problem with incomplete service

NARCIS (Netherlands)

Archetti, Claudia; Bianchessi, Nicola; Speranza, M. Grazia

2013-01-01

In this paper we study the capacitated version of the Team Orienteering Problem (TOP), that is the Capacitated TOP (CTOP) and the impact of relaxing the assumption that a customer, if served, must be completely served. We prove that the profit collected by the CTOP with Incomplete Service (CTOP-IS)

Capacitance for carbon capture

International Nuclear Information System (INIS)

Landskron, Kai

2018-01-01

Metal recycling: A sustainable, capacitance-assisted carbon capture and sequestration method (Supercapacitive Swing Adsorption) can turn scrap metal and CO 2 into metal carbonates at an attractive energy cost. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Automatic Power Factor Correction Using Capacitive Bank

OpenAIRE

Mr.Anant Kumar Tiwari,; Mrs. Durga Sharma

2014-01-01

The power factor correction of electrical loads is a problem common to all industrial companies. Earlier the power factor correction was done by adjusting the capacitive bank manually [1]. The automated power factor corrector (APFC) using capacitive load bank is helpful in providing the power factor correction. Proposed automated project involves measuring the power factor value from the load using microcontroller. The design of this auto-adjustable power factor correction is ...

Experimental investigation on material migration phenomena in micro-EDM of reaction-bonded silicon carbide

Energy Technology Data Exchange (ETDEWEB)

Liew, Pay Jun [Department of Mechanical Systems and Design, Tohoku University, Aramaki Aoba 6-6-01, Aoba-ku, Sendai, 980-8579 (Japan); Manufacturing Process Department, Faculty of Manufacturing Engineering, Universiti Teknikal Malaysia Melaka, Hang Tuah Jaya, 76100, Durian Tunggal, Melaka (Malaysia); Yan, Jiwang, E-mail: yan@mech.keio.ac.jp [Department of Mechanical Engineering, Faculty of Science and Technology, Keio University, Hiyoshi 3-14-1, Kohoku-ku, Yokohama, 223-8522 (Japan); Kuriyagawa, Tsunemoto [Department of Mechanical Systems and Design, Tohoku University, Aramaki Aoba 6-6-01, Aoba-ku, Sendai, 980-8579 (Japan)

2013-07-01

Material migration between tool electrode and workpiece material in micro electrical discharge machining of reaction-bonded silicon carbide was experimentally investigated. The microstructural changes of workpiece and tungsten tool electrode were examined using scanning electron microscopy, cross sectional transmission electron microscopy and energy dispersive X-ray under various voltage, capacitance and carbon nanofibre concentration in the dielectric fluid. Results show that tungsten is deposited intensively inside the discharge-induced craters on the RB-SiC surface as amorphous structure forming micro particles, and on flat surface region as a thin interdiffusion layer of poly-crystalline structure. Deposition of carbon element on tool electrode was detected, indicating possible material migration to the tool electrode from workpiece material, carbon nanofibres and dielectric oil. Material deposition rate was found to be strongly affected by workpiece surface roughness, voltage and capacitance of the electrical discharge circuit. Carbon nanofibre addition in the dielectric at a suitable concentration significantly reduced the material deposition rate.

Experimental investigation on material migration phenomena in micro-EDM of reaction-bonded silicon carbide

International Nuclear Information System (INIS)

Liew, Pay Jun; Yan, Jiwang; Kuriyagawa, Tsunemoto

2013-01-01

Material migration between tool electrode and workpiece material in micro electrical discharge machining of reaction-bonded silicon carbide was experimentally investigated. The microstructural changes of workpiece and tungsten tool electrode were examined using scanning electron microscopy, cross sectional transmission electron microscopy and energy dispersive X-ray under various voltage, capacitance and carbon nanofibre concentration in the dielectric fluid. Results show that tungsten is deposited intensively inside the discharge-induced craters on the RB-SiC surface as amorphous structure forming micro particles, and on flat surface region as a thin interdiffusion layer of poly-crystalline structure. Deposition of carbon element on tool electrode was detected, indicating possible material migration to the tool electrode from workpiece material, carbon nanofibres and dielectric oil. Material deposition rate was found to be strongly affected by workpiece surface roughness, voltage and capacitance of the electrical discharge circuit. Carbon nanofibre addition in the dielectric at a suitable concentration significantly reduced the material deposition rate.

Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

Energy Technology Data Exchange (ETDEWEB)

Ya' akobovitz, A. [Mechanosynthesis Group, Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Mechanical Engineering, Faculty of Engineering Sciences, Ben-Gurion University, Beer-Sheva (Israel); Bedewy, M. [Mechanosynthesis Group, Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Hart, A. J. [Mechanosynthesis Group, Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Mechanical Engineering and Laboratory for Manufacturing and Productivity, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2015-02-02

Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices.

Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

International Nuclear Information System (INIS)

Ya'akobovitz, A.; Bedewy, M.; Hart, A. J.

2015-01-01

Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices

Electrostatic capacitance and Faraday cage behavior of carbon nanotube forests

Science.gov (United States)

Ya'akobovitz, A.; Bedewy, M.; Hart, A. J.

2015-02-01

Understanding of the electrostatic properties of carbon nanotube (CNT) forests is essential to enable their integration in microelectronic and micromechanical devices. In this study, we sought to understand how the hierarchical geometry and morphology of CNT forests determines their capacitance. First, we find that at small gaps, solid micropillars have greater capacitance, yet at larger gaps the capacitance of the CNT forests is greater. The surface area of the CNT forest accessible to the electrostatic field was extracted by analysis of the measured capacitance, and, by relating the capacitance to the average density of CNTs in the forest, we find that the penetration depth of the electrostatic field is on the order of several microns. Therefore, CNT forests can behave as a miniature Faraday cage. The unique electrostatic properties of CNT forests could therefore enable their use as long-range proximity sensors and as shielding elements for miniature electronic devices.

EFFECT OF DIESEL CONTAMINATION ON CAPACITANCE VALUES OF CRUDE PALM OIL

Directory of Open Access Journals (Sweden)

C. H. FIZURA

2014-06-01

Full Text Available Measurement of crude palm oil (CPO contamination is a major concern in CPO quality monitoring. In this study, capacitive sensing technique was used to monitor diesel contamination levels in CPO. A low cost capacitive sensing system was developed by using AD7746 capacitance to digital converter. The capacitance value of CPO samples with different contamination levels (v/v% ranged from 0% to 50% was collected at a room temperature (25°C. The objective of this study is to find a relationship between capacitance values and diesel contamination levels in CPO. The results showed that capacitance value decreased as the diesel contamination levels increased. For the 0% to 50% contamination range, the regression equation was y = 0.0002x2 - 0.0125x + 0.936 with R2 value of 0.96. For the 0% to 10% contamination range (where the percentage was the representative of potential contaminations levels found in CPO the correlation equation was y = -0.02x + 0.95 with R2 value of 0.95. These results indicated that capacitive sensing technique has potential for CPO quality monitoring.

Non-foster matching of an RFID antenna

KAUST Repository

Mohamed Hassan Salem, Nedime Pelin

2011-07-01

Novel designs of radio-frequency identification (RFID) tag antennas with better matching characteristics to achieve extended range for passive tags are investigated in ultra-high frequency (UHF) band. A microstrip dipole antenna with or without an integrated negative impedance converter designed to cancel out the antenna\\'s input capacitance at resonance frequency was designed, simulated, constructed and measured for implementation in RFID applications. © 2011 IEEE.

High Voltage Bi-directional Flyback Converter for Capacitive Actuator

DEFF Research Database (Denmark)

Thummala, Prasanth; Zhang, Zhe; Andersen, Michael A. E.

2013-01-01

in the converter, including the most dominating parameters of the high voltage transformer viz., self-capacitance and leakage inductance. The specific capacitive load for this converter is a dielectric electro active polymer (DEAP) actuator, which can be used as an effective replacement for conventional actuators...... in a number of applications. In this paper, the discharging energy efficiency definition is introduced. The proposed converter has been experimentally tested with the film capacitive load and the DEAP actuator, and the experimental results are shown together with the efficiency measurements....

Stressing effects on the charge trapping of silicon oxynitride prepared by thermal oxidation of LPCVD Si-rich silicon nitride

International Nuclear Information System (INIS)

Choi, H.Y.; Wong, H.; Filip, V.; Sen, B.; Kok, C.W.; Chan, M.; Poon, M.C.

2006-01-01

It was recently found that the silicon oxynitride prepared by oxidation of silicon-rich silicon nitride (SRN) has several important features. The high nitrogen and extremely low hydrogen content of this material allows it to have a high dielectric constant and a low trap density. The present work investigates in further detail the electrical reliability of this kind of gate dielectric films by studying the charge trapping and interface state generation induced by constant current stressing. Capacitance-voltage (C-V) measurements indicate that for oxidation temperatures of 850 and 950 deg. C, the interface trap generation is minimal because of the high nitrogen content at the interface. At a higher oxidation temperature of 1050 deg. C, a large flatband shift is found for constant current stressing. This observation can be explained by the significant reduction of the nitrogen content and the phase separation effect at this temperature as found by X-ray photoelectron spectroscopy study. In addition to the high nitrogen content, the Si atoms at the interface exist in the form of random bonding to oxygen and nitrogen atoms for samples oxidized at 850 and 950 deg. C. This structure reduces the interface bonding constraint and results in the low interface trap density. For heavily oxidized samples the trace amount of interface nitrogen atoms exist in the form of a highly constraint SiN 4 phase and the interface oxynitride layer is a random mixture of SiO 4 and SiN 4 phases, which consequently reduces the reliability against high energy electron stressing

Capacitance for carbon capture

Energy Technology Data Exchange (ETDEWEB)

Landskron, Kai [Department of Chemistry, Lehigh University, Bethlehem, PA (United States)

2018-03-26

Metal recycling: A sustainable, capacitance-assisted carbon capture and sequestration method (Supercapacitive Swing Adsorption) can turn scrap metal and CO{sub 2} into metal carbonates at an attractive energy cost. (copyright 2018 Wiley-VCH Verlag GmbH and Co. KGaA, Weinheim)

Nanoscale capacitance imaging with attofarad resolution using ac current sensing atomic force microscopy

International Nuclear Information System (INIS)

Fumagalli, L; Ferrari, G; Sampietro, M; Casuso, I; MartInez, E; Samitier, J; Gomila, G

2006-01-01

Nanoscale capacitance imaging with attofarad resolution (∼1 aF) of a nano-structured oxide thin film, using ac current sensing atomic force microscopy, is reported. Capacitance images are shown to follow the topographic profile of the oxide closely, with nanometre vertical resolution. A comparison between experimental data and theoretical models shows that the capacitance variations observed in the measurements can be mainly associated with the capacitance probed by the tip apex and not with positional changes of stray capacitance contributions. Capacitance versus distance measurements further support this conclusion. The application of this technique to the characterization of samples with non-voltage-dependent capacitance, such as very thin dielectric films, self-assembled monolayers and biological membranes, can provide new insight into the dielectric properties at the nanoscale

Nanoscale capacitance imaging with attofarad resolution using ac current sensing atomic force microscopy

Energy Technology Data Exchange (ETDEWEB)

Fumagalli, L [Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 (Italy); Ferrari, G [Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 (Italy); Sampietro, M [Dipartimento di Elettronica e Informazione, Politecnico di Milano, Piazza Leonardo da Vinci 32, I-20133 (Italy); Casuso, I [Departament d' Electronica, Universitat de Barcelona, C/MartIi Franques 1, 08028 Barcelona (Spain); MartInez, E [Plataforma de Nanotecnologia, Parc Cientific de Barcelona, C/ Josep Samitier 1-5, 08028-Barcelona (Spain); Samitier, J [Departament d' Electronica, Universitat de Barcelona, C/MartIi Franques 1, 08028 Barcelona (Spain); Gomila, G [Departament d' Electronica, Universitat de Barcelona, C/MartIi Franques 1, 08028 Barcelona (Spain)

2006-09-28

Nanoscale capacitance imaging with attofarad resolution ({approx}1 aF) of a nano-structured oxide thin film, using ac current sensing atomic force microscopy, is reported. Capacitance images are shown to follow the topographic profile of the oxide closely, with nanometre vertical resolution. A comparison between experimental data and theoretical models shows that the capacitance variations observed in the measurements can be mainly associated with the capacitance probed by the tip apex and not with positional changes of stray capacitance contributions. Capacitance versus distance measurements further support this conclusion. The application of this technique to the characterization of samples with non-voltage-dependent capacitance, such as very thin dielectric films, self-assembled monolayers and biological membranes, can provide new insight into the dielectric properties at the nanoscale.

Capacitance probe for detection of anomalies in non-metallic plastic pipe

Science.gov (United States)

Mathur, Mahendra P.; Spenik, James L.; Condon, Christopher M.; Anderson, Rodney; Driscoll, Daniel J.; Fincham, Jr., William L.; Monazam, Esmail R.

2010-11-23

The disclosure relates to analysis of materials using a capacitive sensor to detect anomalies through comparison of measured capacitances. The capacitive sensor is used in conjunction with a capacitance measurement device, a location device, and a processor in order to generate a capacitance versus location output which may be inspected for the detection and localization of anomalies within the material under test. The components may be carried as payload on an inspection vehicle which may traverse through a pipe interior, allowing evaluation of nonmetallic or plastic pipes when the piping exterior is not accessible. In an embodiment, supporting components are solid-state devices powered by a low voltage on-board power supply, providing for use in environments where voltage levels may be restricted.

Electrochemical behavior of amorphous metal-silicon-carbon nanocomposites based on titanium or tungsten nanophase

International Nuclear Information System (INIS)

Pleskov, Yu.V.; Krotova, M.D.; Shupegin, M.L.; Bozhko, A.D.

2009-01-01

Electrode behavior of nanocomposite films containing titanium- or tungsten-based conducting nanophase embedded in dielectric silicon-carbon matrix, deposited onto glassceramics substrate, is studied by cyclic voltammetry and electrochemical impedance spectroscopy. As the films' resistivity decreases, their electrochemical behavior gradually changes from that of 'poor conductor' to the nearly metal-like behavior. In particular, the differential capacitance increases, the charge transfer in a model redox system [Fe(CN) 6 ] 3-/4- accelerates, which may be explained by the increasing number of metal-containing clusters at the film/electrolyte solution interface

Low Power/Low Voltage Interface Circuitry for Capacitive Sensors

DEFF Research Database (Denmark)

Furst, Claus Efdmann

This thesis focuses mainly on low power/low voltage interface circuits, implemented in CMOS, for capacitive sensors. A brief discussion of demands and possibilities for analog signal processing in the future is presented. Techniques for low power design is presented. This is done by analyzing power...... power consumption. It is shown that the Sigma-Delta modulator is advantageous when embedded in a feedback loop with a mechanical sensor. Here a micro mechanical capacitive microphone. Feedback and detection circuitry for a capacitive microphone is presented. Practical implementations of low power....../low voltage interface circuitry is presented. It is demonstrated that an amplifier optimized for a capacitive microphone implemented in a standard 0.7 micron CMOS technology competes well with a traditional JFET amplifier. Furthermore a low power/low voltage 3rd order Sigma-Delta modulator is presented...

Development of electrical capacitance sensor for tomography

International Nuclear Information System (INIS)

Rasif Mohd Zain; Jaafar Abdullah; Ismail Mustapha; Sazrol Azizee Ariff; Susan Maria Sipaun; Lojius Lombigit

2004-01-01

Electrical capacitance tomography (ECT) is one of the successful methods for imaging 2-phase liquid/gas mixture in oil pipelines and solids/gas mixture in fluidized bed and pneumatic conveying system for improvement of process plants. This paper presents the design development of an electrical capacitance sensor for use with an ECT system. This project is aimed at developing a demonstration ECT unit to be used in the oil pipe line. (Author)

Capacitance-Power-Hysteresis Trilemma in Nanoporous Supercapacitors

OpenAIRE

Lee, Alpha A; Vella, Dominic; Goriely, Alain; Kondrat, Svyatoslav

2015-01-01

Nanoporous supercapacitors are an important player in the field of energy storage that fill the gap between dielectric capacitors and batteries. The key challenge in the development of supercapacitors is the perceived trade-off between capacitance and power delivery. Current efforts to boost the capacitance of nanoporous supercapacitors focus on reducing the pore size so that they can only accommodate a single layer of ions. However, this tight packing compromises the charging dynamics and he...

Capacitance and surface of carbons in supercapacitors

OpenAIRE

Lobato Ortega, Belén; Suárez Fernández, Loreto; Guardia, Laura; Álvarez Centeno, Teresa

2017-01-01

This research is focused in the missing link between the specific surface area of carbons surface and their electrochemical capacitance. Current protocols used for the characterization of carbons applied in supercapacitors electrodes induce inconsistencies in the values of the interfacial capacitance (in F m−2), which is hindering the optimization of supercapacitors. The constraints of both the physisorption of N2 at 77 K and the standard methods used for the isotherm analysis frequently lead...

Electron drift time in silicon drift detectors: A technique for high precision measurement of electron drift mobility

International Nuclear Information System (INIS)

Castoldi, A.; Rehak, P.

1995-01-01

This paper presents a precise absolute measurement of the drift velocity and mobility of electrons in high resistivity silicon at room temperature. The electron velocity is obtained from the differential measurement of the drift time of an electron cloud in a silicon drift detector. The main features of the transport scheme of this class of detectors are: the high uniformity of the electron motion, the transport of the signal electrons entirely contained in the high-purity bulk, the low noise timing due to the very small anode capacitance (typical value 100 fF), and the possibility to measure different drift distances, up to the wafer diameter, in the same semiconductor sample. These features make the silicon drift detector an optimal device for high precision measurements of carrier drift properties. The electron drift velocity and mobility in a 10 kΩ cm NTD n-type silicon wafer have been measured as a function of the electric field in the range of possible operation of a typical drift detector (167--633 V/cm). The electron ohmic mobility is found to be 1394 cm 2 /V s. The measurement precision is better than 1%. copyright 1995 American Institute of Physics

Dispersion capacitive de l'interface H2SO4/Pt Capacitive dispersion ...

African Journals Online (AJOL)

Administrateur

Département de Physique, Faculté des Sciences Exactes. Université des .... d'un comportement idéal de la capacité. Au vu .... Figure 2 : Photographie de la cellule Pt/0,5 MH2SO4 (fabriquée par Verre-Lab Constantine) plongée dans un bain.

Capacitance level probe, Type FSK 88

International Nuclear Information System (INIS)

Vogt, W.

2001-01-01

The aim of the capacitive level probe, Type FSK 88, is to supervise the level within vessels continuously and to signalize alterations immediately. Since 1987 the level probe is installed in the pool for burn up fuel elements and in the reactor containment sump of BWRs, PWRs and WWERs. The capacitive level probe of type FSK 88 was qualified for Loss of Coolant Accidents and seismic events according to international rules. The measuring principle takes credit from the fact that the dielectric with different dielectric constants in a condensator changes the capacity of the condensator. (Authors)

Clean energy generation using capacitive electrodes in reverse electrodialysis

NARCIS (Netherlands)

Vermaas, David; Bajracharya, S.; Bastos Sales, B.; Saakes, Michel; Hamelers, B.; Nijmeijer, Dorothea C.

2013-01-01

Capacitive reverse electrodialysis (CRED) is a newly proposed technology to generate electricity from mixing of salt water and fresh water (salinity gradient energy) by using a membrane pile as in reverse electrodialysis (RED) and capacitive electrodes. The salinity difference between salt water and

Accurate sizing of supercapacitors storage system considering its capacitance variation.

OpenAIRE

Trieste , Sony; Bourguet , Salvy; Olivier , Jean-Christophe; Loron , Luc; Le Claire , Jean-Claude

2011-01-01

International audience; This paper highlights the energy errors made for the design of supercapacitors used as a main energy source. First of all, the paper presents the two definitions of capacitance of a capacitance-voltage dependent material. The number of supercapacitors is important for the application purchasing cost. That is why the paper introduces an analytical model and an electrical model along with an identification method for the capacitance variation. This variation is presented...

Development of a Novel Transparent Flexible Capacitive Micromachined Ultrasonic Transducer

Directory of Open Access Journals (Sweden)

Da-Chen Pang

2017-06-01

Full Text Available This paper presents the world’s first transparent flexible capacitive micromachined ultrasonic transducer (CMUT that was fabricated through a roll-lamination technique. This polymer-based CMUT has advantages of transparency, flexibility, and non-contacting detection which provide unique functions in display panel applications. Comprising an indium tin oxide-polyethylene terephthalate (ITO-PET substrate, SU-8 sidewall and vibrating membranes, and silver nanowire transparent electrode, the transducer has visible-light transmittance exceeding 80% and can operate on curved surfaces with a 40 mm radius of curvature. Unlike the traditional silicon-based high temperature process, the CMUT can be fabricated on a flexible substrate at a temperature below 100 °C to reduce residual stress introduced at high temperature. The CMUT on the curved surfaces can detect a flat target and finger at distances up to 50 mm and 40 mm, respectively. The transparent flexible CMUT provides a better human-machine interface than existing touch panels because it can be integrated with a display panel for non-contacting control in a health conscious environment and the flexible feature is critical for curved display and wearable electronics.

Design of capacitance measurement module for determining critical cold temperature of tea leaves

Directory of Open Access Journals (Sweden)

Yongzong Lu

2016-12-01

Full Text Available Critical cold temperature is one of the most crucial control factors for crop frost protection. Tea leaf's capacitance has a significant response to cold injury and appears as a peak response to a typical low temperature which is the critical temperature. However, the testing system is complex and inconvenient. In view of these, a tea leaf's critical temperature detector based on capacitance measurement module was designed and developed to measure accurately and conveniently the capacitance. Software was also designed to measure parameters, record data, query data as well as data deletion module. The detector utilized the MSP430F149 MCU as the control core and ILI9320TFT as the display module, and its software was compiled by IAR5.3. Capacitance measurement module was the crucial part in the overall design which was based on the principle of oscillator. Based on hardware debugging and stability analysis of capacitance measurement module, it was found that the output voltage of the capacitance measurement circuit is stable with 0.36% average deviation. The relationship between capacitance and 1/Uc2 was found to be linear distribution with the determination coefficient above 0.99. The result indicated that the output voltage of capacitance measurement module well corresponded to the change in value of the capacitance. The measurement error of the circuit was also within the required range of 0 to 100 pF which meets the requirement of tea leaf's capacitance. Keywords: Tea leaves, Critical cold temperature, Capacitance peak response, Frost protection, Detector

Measurement of gas-liquid two-phase flow in micro-pipes by a capacitance sensor.

Science.gov (United States)

Ji, Haifeng; Li, Huajun; Huang, Zhiyao; Wang, Baoliang; Li, Haiqing

2014-11-26

A capacitance measurement system is developed for the measurement of gas-liquid two-phase flow in glass micro-pipes with inner diameters of 3.96, 2.65 and 1.56 mm, respectively. As a typical flow regime in a micro-pipe two-phase flow system, slug flow is chosen for this investigation. A capacitance sensor is designed and a high-resolution and high-speed capacitance measurement circuit is used to measure the small capacitance signals based on the differential sampling method. The performance and feasibility of the capacitance method are investigated and discussed. The capacitance signal is analyzed, which can reflect the voidage variation of two-phase flow. The gas slug velocity is determined through a cross-correlation technique using two identical capacitance sensors. The simulation and experimental results show that the presented capacitance measurement system is successful. Research work also verifies that the capacitance sensor is an effective method for the measurement of gas liquid two-phase flow parameters in micro-pipes.

Non-axisymmetric flexural vibrations of free-edge circular silicon wafers

Energy Technology Data Exchange (ETDEWEB)

Dmitriev, A.V., E-mail: dmitriev@hbar.phys.msu.ru; Gritsenko, D.S.; Mitrofanov, V.P., E-mail: mitr@hbar.phys.msu.ru

2014-02-07

Non-axisymmetric flexural vibrations of circular silicon (111) wafers are investigated. The modes with azimuthal index 2⩽k⩽30 are electrostatically excited and monitored by a capacitive sensor. The splitting of the mode frequencies associated with imperfection of the wafer is observed. The measured loss factors for the modes with 6≲k≲26 are close to those calculated according to the thermoelastic damping theory, while clamping losses likely dominate for k≲6, and surface losses at the level of inverse Q-factor Q{sup −1}≈4×10{sup −6} prevail for the modes with large k. The modes demonstrate nonlinear behavior of mainly geometrical origin at large amplitudes.

Electric field theory and the fallacy of void capacitance

DEFF Research Database (Denmark)

McAllister, Iain Wilson

1991-01-01

The concept of the capacitance of a gaseous void is discussed as applied to electrical insulation science. The most pertinent aspect of the capacitance definition is that of reference to a single-valued potential difference between surfaces. This implies that these surfaces must be surfaces...

Gain calibration of n-XYTER 1.0 - a prototype readout ASIC for the silicon tracking system of the CBM experiment

Energy Technology Data Exchange (ETDEWEB)

Sorokin, Iurii [Goethe Univ. Frankfurt am Main (Germany); Kiev Institute for Nuclear Research (Ukraine); Collaboration: CBM-Collaboration

2013-07-01

n-XYTER is a 128-channel readout ASIC which measures both the integral signal charge and the time of occurance. Due to its self-triggering design, high gain, high rate capability and bipolar front-end, the chip has found a use as a prototype readout for the Silicon Tracking System, Muon and Cherenkov detectors of the CBM experiment. It is also going to be applied in other projects in Darmstadt, Heidelberg and Dubna. To perform gain calibration of n-XYTER, reference charge pulses of a very small (down to 3000 e{sup -}), yet precisely known amplitude had to be generated. This was achieved by attenuating a voltage step to a sub-millivolt level and passing it through a tiny (1 pF) capacitor. Special care had to be taken to check for possible systematic errors in the measurements of the attenuation factor and of the coupling capacitance. In addition, the system had to be well shielded against RF pickup, the parasitic capacitances had to be minimized and ensured to stay invariable. Correct estimate of the systematic error was confirmed by performing a measurement with a different signal source - a planar silicon detector, exposed to γ-radiation of {sup 241}Am. Finally, the dominating error came from the channel-to-channel gain variation.

Capacitive Coupling in Double-Circuit Transmission Lines

Directory of Open Access Journals (Sweden)

Zdenka Benesova

2004-01-01

Full Text Available The paper describes an algorithm for calculation of capacitances and charges on conductors in systems with earth wires and in double-circuit overhead lines with respect to phase arrangement. A balanced voltage system is considered. A suitable transposition of individual conductors enables to reduce the electric and magnetic fields in vicinity of overhead lines and to limit the inductive and capacitive linkage. The procedure is illustrated on examples the results of which lead to particular recommendations for designers.

Transparent Flexible Active Faraday Cage Enables In Vivo Capacitance Measurement in Assembled Microsensor.

Science.gov (United States)

Ahmadi, Mahdi; Rajamani, Rajesh; Sezen, Serdar

2017-10-01

Capacitive micro-sensors such as accelerometers, gyroscopes and pressure sensors are increasingly used in the modern electronic world. However, the in vivo use of capacitive sensing for measurement of pressure or other variables inside a human body suffers from significant errors due to stray capacitance. This paper proposes a solution consisting of a transparent thin flexible Faraday cage that surrounds the sensor. By supplying the active sensing voltage simultaneously to the deformable electrode of the capacitive sensor and to the Faraday cage, the stray capacitance during in vivo measurements can be largely eliminated. Due to the transparency of the Faraday cage, the top and bottom portions of a capacitive sensor can be accurately aligned and assembled together. Experimental results presented in the paper show that stray capacitance is reduced by a factor of 10 by the Faraday cage, when the sensor is subjected to a full immersion in water.

An integrated energy-efficient capacitive sensor digital interface circuit

KAUST Repository

Omran, Hesham

2014-06-19

In this paper, we propose an energy-efficient 13-bit capacitive sensor interface circuit. The proposed design fully relies on successive approximation algorithm, which eliminates the need for oversampling and digital decimation filtering, and thus low-power consumption is achieved. The proposed architecture employs a charge amplifier stage to acheive parasitic insensitive operation and fine absolute resolution. Moreover, the output code is not affected by offset voltages or charge injection. The successive approximation algorithm is implemented in the capacitance-domain using a coarse-fine programmable capacitor array, which allows digitizing wide capacitance range in compact area. Analysis for the maximum achievable resolution due to mismatch is provided. The proposed design is insensitive to any reference voltage or current which translates to low temperature sensitivity. The operation of a prototype fabricated in a standard CMOS technology is experimentally verified using both on-chip and off-chip capacitive sensors. Compared to similar prior work, the fabricated prototype achieves and excellent energy efficiency of 34 pJ/step.

Concentration Fluctuations and Capacitive Response in Dense Ionic Solutions.

Science.gov (United States)

Uralcan, Betul; Aksay, Ilhan A; Debenedetti, Pablo G; Limmer, David T

2016-07-07

We use molecular dynamics simulations in a constant potential ensemble to study the effects of solution composition on the electrochemical response of a double layer capacitor. We find that the capacitance first increases with ion concentration following its expected ideal solution behavior but decreases upon approaching a pure ionic liquid in agreement with recent experimental observations. The nonmonotonic behavior of the capacitance as a function of ion concentration results from the competition between the independent motion of solvated ions in the dilute regime and solvation fluctuations in the concentrated regime. Mirroring the capacitance, we find that the characteristic decay length of charge density correlations away from the electrode is also nonmonotonic. The correlation length first decreases with ion concentration as a result of better electrostatic screening but increases with ion concentration as a result of enhanced steric interactions. When charge fluctuations induced by correlated ion-solvent fluctuations are large relative to those induced by the pure ionic liquid, such capacitive behavior is expected to be generic.

Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

Directory of Open Access Journals (Sweden)

Ben Minnaert

2017-01-01

Full Text Available Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this optimal network as a function of the characteristics of the capacitive wireless link, as well for the series as for the parallel topology. The results are compared with the inductive power transfer system. Introduction of a new concept, the coupling function, enables the description of the compensation network of both an inductive and a capacitive system in two elegant equations, valid for the series and the parallel topology. This approach allows better understanding of the fundamentals of the wireless power transfer link, necessary for the design of an efficient system.

Design and implementation of a high sensitivity fully integrated passive UHF RFID tag

International Nuclear Information System (INIS)

Li Shoucheng; Wang Xin'an; Lin Ke; Shen Jinpeng; Zhang Jinhai

2014-01-01

A fully integrated passive UHF RFID tag complying with the ISO18000-6B protocol is presented, which includes an analog front-end, a baseband processor, and an EEPROM memory. To extend the communication range, a high efficiency differential-drive CMOS rectifier is adopted. A novel high performance voltage limiter is used to provide a stable limiting voltage, with a 172 mV voltage variation against temperature variation and process dispersion. The dynamic band-enhancement technique is used in the regulator circuit to improve the regulating capacity. A rail-to-rail hysteresis comparator is adopted to demodulate the signal correctly in any condition. The whole transponder chip is implemented in a 0.18 μm CMOS process, with a die size of 900 × 800 μm 2 . Our measurement results show that the total power consumption of the tag chip is only 6.8 μW, with a sensitivity of −13.5 dBm (semiconductor integrated circuits)

MEMS capacitive accelerometer-based middle ear microphone.

Science.gov (United States)

Young, Darrin J; Zurcher, Mark A; Semaan, Maroun; Megerian, Cliff A; Ko, Wen H

2012-12-01

The design, implementation, and characterization of a microelectromechanical systems (MEMS) capacitive accelerometer-based middle ear microphone are presented in this paper. The microphone is intended for middle ear hearing aids as well as future fully implantable cochlear prosthesis. Human temporal bones acoustic response characterization results are used to derive the accelerometer design requirements. The prototype accelerometer is fabricated in a commercial silicon-on-insulator (SOI) MEMS process. The sensor occupies a sensing area of 1 mm × 1 mm with a chip area of 2 mm × 2.4 mm and is interfaced with a custom-designed low-noise electronic IC chip over a flexible substrate. The packaged sensor unit occupies an area of 2.5 mm × 6.2 mm with a weight of 25 mg. The sensor unit attached to umbo can detect a sound pressure level (SPL) of 60 dB at 500 Hz, 35 dB at 2 kHz, and 57 dB at 8 kHz. An improved sound detection limit of 34-dB SPL at 150 Hz and 24-dB SPL at 500 Hz can be expected by employing start-of-the-art MEMS fabrication technology, which results in an articulation index of approximately 0.76. Further micro/nanofabrication technology advancement is needed to enhance the microphone sensitivity for improved understanding of normal conversational speech.

First UHF Implementation of the Incremental Scheme for Open-Shell Systems.

Science.gov (United States)

Anacker, Tony; Tew, David P; Friedrich, Joachim

2016-01-12

The incremental scheme makes it possible to compute CCSD(T) correlation energies to high accuracy for large systems. We present the first extension of this fully automated black-box approach to open-shell systems using an Unrestricted Hartree-Fock (UHF) wave function, extending the efficient domain-specific basis set approach to handle open-shell references. We test our approach on a set of organic and metal organic structures and molecular clusters and demonstrate standard deviations from canonical CCSD(T) values of only 1.35 kJ/mol using a triple ζ basis set. We find that the incremental scheme is significantly more cost-effective than the canonical implementation even for relatively small systems and that the ease of parallelization makes it possible to perform high-level calculations on large systems in a few hours on inexpensive computers. We show that the approximations that make our approach widely applicable are significantly smaller than both the basis set incompleteness error and the intrinsic error of the CCSD(T) method, and we further demonstrate that incremental energies can be reliably used in extrapolation schemes to obtain near complete basis set limit CCSD(T) reaction energies for large systems.

Improving accuracy of electrochemical capacitance and solvation energetics in first-principles calculations

Science.gov (United States)

Sundararaman, Ravishankar; Letchworth-Weaver, Kendra; Schwarz, Kathleen A.

2018-04-01

Reliable first-principles calculations of electrochemical processes require accurate prediction of the interfacial capacitance, a challenge for current computationally efficient continuum solvation methodologies. We develop a model for the double layer of a metallic electrode that reproduces the features of the experimental capacitance of Ag(100) in a non-adsorbing, aqueous electrolyte, including a broad hump in the capacitance near the potential of zero charge and a dip in the capacitance under conditions of low ionic strength. Using this model, we identify the necessary characteristics of a solvation model suitable for first-principles electrochemistry of metal surfaces in non-adsorbing, aqueous electrolytes: dielectric and ionic nonlinearity, and a dielectric-only region at the interface. The dielectric nonlinearity, caused by the saturation of dipole rotational response in water, creates the capacitance hump, while ionic nonlinearity, caused by the compactness of the diffuse layer, generates the capacitance dip seen at low ionic strength. We show that none of the previously developed solvation models simultaneously meet all these criteria. We design the nonlinear electrochemical soft-sphere solvation model which both captures the capacitance features observed experimentally and serves as a general-purpose continuum solvation model.

A 240-channel thick film multi-chip module for readout of silicon drift detectors

International Nuclear Information System (INIS)

Lynn, D.; Bellwied, R.; Beuttenmueller, R.; Caines, H.; Chen, W.; DiMassimo, D.; Dyke, H.; Elliott, D.; Grau, M.; Hoffmann, G.W.; Humanic, T.; Jensen, P.; Kleinfelder, S.A.; Kotov, I.; Kraner, H.W.; Kuczewski, P.; Leonhardt, B.; Li, Z.; Liaw, C.J.; LoCurto, G.; Middelkamp, P.; Minor, R.; Mazeh, N.; Nehmeh, S.; O'Conner, P.; Ott, G.; Pandey, S.U.; Pruneau, C.; Pinelli, D.; Radeka, V.; Rescia, S.; Rykov, V.; Schambach, J.; Sedlmeir, J.; Sheen, J.; Soja, B.; Stephani, D.; Sugarbaker, E.; Takahashi, J.; Wilson, K.

2000-01-01

We have developed a thick film multi-chip module for readout of silicon drift (or low capacitance ∼200 fF) detectors. Main elements of the module include a custom 16-channel NPN-BJT preamplifier-shaper (PASA) and a custom 16-channel CMOS Switched Capacitor Array (SCA). The primary design criteria of the module were the minimizations of the power (12 mW/channel), noise (ENC=490 e - rms), size (20.5 mmx63 mm), and radiation length (1.4%). We will discuss various aspects of the PASA design, with emphasis on the preamplifier feedback network. The SCA is a modification of an integrated circuit that has been previously described [1]; its design features specific to its application in the SVT (Silicon Vertex Tracker in the STAR experiment at RHIC) will be discussed. The 240-channel multi-chip module is a circuit with five metal layers fabricated in thick film technology on a beryllia substrate and contains 35 custom and commercial integrated circuits. It has been recently integrated with silicon drift detectors in both a prototype system assembly for the SVT and a silicon drift array for the E896 experiment at the Alternating Gradient Synchrotron at the Brookhaven National Laboratory. We will discuss features of the module's design and fabrication, report the test results, and emphasize its performance both on the bench and under experimental conditions

Contribution of Dielectric Screening to the Total Capacitance of Few-Layer Graphene Electrodes.

Science.gov (United States)

Zhan, Cheng; Jiang, De-en

2016-03-03

We apply joint density functional theory (JDFT), which treats the electrode/electrolyte interface self-consistently, to an electric double-layer capacitor (EDLC) based on few-layer graphene electrodes. The JDFT approach allows us to quantify a third contribution to the total capacitance beyond quantum capacitance (CQ) and EDL capacitance (CEDL). This contribution arises from the dielectric screening of the electric field by the surface of the few-layer graphene electrode, and we therefore term it the dielectric capacitance (CDielec). We find that CDielec becomes significant in affecting the total capacitance when the number of graphene layers in the electrode is more than three. Our investigation sheds new light on the significance of the electrode dielectric screening on the capacitance of few-layer graphene electrodes.

Development of an Intelligent Capacitive Mass Sensor Based on Co-axial Cylindrical Capacitor

Directory of Open Access Journals (Sweden)

Amir ABU AL AISH

2009-06-01

Full Text Available The paper presents a linear, robust and intelligent capacitive mass sensor made of a co-axial cylindrical capacitor. It is designed such that the mass under measurement is directly proportional to the capacitance of the sensor. The average value of the output voltage of a capacitance to voltage converter is proportional to the capacitance of the sensor. The output of the converter is measured and displayed, as mass, with the help of microcontroller. The results are free from the effect of stray capacitances which cause errors at low values of capacitances. Developed sensor is linear, free from errors due to temperature and highly flexible in design. The proto-type of the mass sensor can weigh up to 4 kilogram only.

Electrochemical and Capacitive Properties of Carbon Dots/Reduced Graphene Oxide Supercapacitors.

Science.gov (United States)

Dang, Yong-Qiang; Ren, Shao-Zhao; Liu, Guoyang; Cai, Jiangtao; Zhang, Yating; Qiu, Jieshan

2016-11-14

There is much recent interest in graphene-based composite electrode materials because of their excellent mechanical strengths, high electron mobilities, and large specific surface areas. These materials are good candidates for applications in supercapacitors. In this work, a new graphene-based electrode material for supercapacitors was fabricated by anchoring carbon dots (CDs) on reduced graphene oxide (rGO). The capacitive properties of electrodes in aqueous electrolytes were systematically studied by galvanostatic charge-discharge measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. The capacitance of rGO was improved when an appropriate amount of CDs were added to the material. The CD/rGO electrode exhibited a good reversibility, excellent rate capability, fast charge transfer, and high specific capacitance in 1 M H₂SO₄. Its capacitance was as high as 211.9 F/g at a current density of 0.5 A/g. This capacitance was 74.3% higher than that of a pristine rGO electrode (121.6 F/g), and the capacitance of the CD/rGO electrode retained 92.8% of its original value after 1000 cycles at a CDs-to-rGO ratio of 5:1.

Electrochemical and Capacitive Properties of Carbon Dots/Reduced Graphene Oxide Supercapacitors

Directory of Open Access Journals (Sweden)

Yong-Qiang Dang

2016-11-01

Full Text Available There is much recent interest in graphene-based composite electrode materials because of their excellent mechanical strengths, high electron mobilities, and large specific surface areas. These materials are good candidates for applications in supercapacitors. In this work, a new graphene-based electrode material for supercapacitors was fabricated by anchoring carbon dots (CDs on reduced graphene oxide (rGO. The capacitive properties of electrodes in aqueous electrolytes were systematically studied by galvanostatic charge-discharge measurements, cyclic voltammetry, and electrochemical impedance spectroscopy. The capacitance of rGO was improved when an appropriate amount of CDs were added to the material. The CD/rGO electrode exhibited a good reversibility, excellent rate capability, fast charge transfer, and high specific capacitance in 1 M H2SO4. Its capacitance was as high as 211.9 F/g at a current density of 0.5 A/g. This capacitance was 74.3% higher than that of a pristine rGO electrode (121.6 F/g, and the capacitance of the CD/rGO electrode retained 92.8% of its original value after 1000 cycles at a CDs-to-rGO ratio of 5:1.

The Design of Phase-Locked-Loop Circuit for Precision Capacitance Micrometer

Directory of Open Access Journals (Sweden)

Li Shujie

2016-01-01

Full Text Available High precision non-contact micrometer is normally divided into three categories: inductance micrometer, capacitance micrometer and optical interferometer micrometer. The capacitance micrometer is widely used because it has high performance to price ratio. With the improvement of automation level, precision of capacitance micrometer is required higher and higher. Generally, capacitance micrometer consists of the capacitance sensor, capacitance/voltage conversion circuit, and modulation and demodulation circuits. However, due to the existing of resistors, capacitors and other components in the circuit, the phase shift of the carrier signal and the modulated signal might occur. In this case, the specific value of phase shift cannot be determined. Therefore, error caused by the phase shift cannot be eliminated. This will reduce the accuracy of micrometer. In this design, in order to eliminate the impact of the phase shift, the phase-locked-loop (PLL circuit is employed. Through the experiment, the function of tracking the input signal phase and frequency is achieved by the phase-locked-loop circuit. This signal processing method can also be applied to tuber electrical resistance tomography system and other precision measurement circuit.

Capacitive sensing of droplets for microfluidic devices based on thermocapillary actuation.

Science.gov (United States)

Chen, Jian Z; Darhuber, Anton A; Troian, Sandra M; Wagner, Sigurd

2004-10-01

The design and performance of a miniaturized coplanar capacitive sensor is presented whose electrode arrays can also function as resistive microheaters for thermocapillary actuation of liquid films and droplets. Optimal compromise between large capacitive signal and high spatial resolution is obtained for electrode widths comparable to the liquid film thickness measured, in agreement with supporting numerical simulations which include mutual capacitance effects. An interdigitated, variable width design, allowing for wider central electrodes, increases the capacitive signal for liquid structures with non-uniform height profiles. The capacitive resolution and time response of the current design is approximately 0.03 pF and 10 ms, respectively, which makes possible a number of sensing functions for nanoliter droplets. These include detection of droplet position, size, composition or percentage water uptake for hygroscopic liquids. Its rapid response time allows measurements of the rate of mass loss in evaporating droplets.

Calculating and optimizing inter-electrode capacitances of charge division microchannel plate detectors

Energy Technology Data Exchange (ETDEWEB)

Xing, Yan [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Chen, Bo, E-mail: chenb@ciomp.ac.cn [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Zhang, Hong-Ji; Wang, Hai-Feng; He, Ling-Ping [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); Jin, Fang-Yuan [Changchun Institute of Optics, Fine Mechanics and Physics, Chinese Academy of Sciences, Changchun 130033 (China); University of Chinese Academy of Sciences, Beijing 100049 (China)

2016-04-01

Based on the principle of charge division microchannel plate detectors, the inter-electrode capacitances of charge division anodes which are related to electronic noise of the charge sensitive amplifier and crosstalk effect of the anode are presented. Under all the requirements of charge division microchannel plate detectors such as the imaging linearity and spatial resolution, decreasing the inter-electrode capacitances is one way to improve the imaging performance. In this paper, we illustrate the simulation process of calculating the inter-electrode capacitances. Moreover, a Wedge and Strip (WSZ) anode is fabricated with the picosecond laser micromachining process. Comparing the simulated capacitances and measured capacitances, the three-dimensional finite element method is proved to be valid. Furthermore, by adjusting the design parameters of the anode, the effects of the substrate permittivity, insulation width and the size of pitch on the inter-electrode capacitances have been analysed. The structure of the charge division anode has been optimized based on the simulation data.

Analytical expressions for noise and crosstalk voltages of the High Energy Silicon Particle Detector

Science.gov (United States)

Yadav, I.; Shrimali, H.; Liberali, V.; Andreazza, A.

2018-01-01

The paper presents design and implementation of a silicon particle detector array with the derived closed form equations of signal-to-noise ratio (SNR) and crosstalk voltages. The noise analysis demonstrates the effect of interpixel capacitances (IPC) between center pixel (where particle hits) and its neighbouring pixels, resulting as a capacitive crosstalk. The pixel array has been designed and simulated in a 180 nm BCD technology of STMicroelectronics. The technology uses the supply voltage (VDD) of 1.8 V and the substrate potential of -50 V. The area of unit pixel is 250×50 μm2 with the substrate resistivity of 125 Ωcm and the depletion depth of 30 μm. The mathematical model includes the effects of various types of noise viz. the shot noise, flicker noise, thermal noise and the capacitive crosstalk. This work compares the results of noise and crosstalk analysis from the proposed mathematical model with the circuit simulation results for a given simulation environment. The results show excellent agreement with the circuit simulations and the mathematical model. The average relative error (AVR) generated for the noise spectral densities with respect to the simulations and the model is 12% whereas the comparison gives the errors of 3% and 11.5% for the crosstalk voltages and the SNR results respectively.

Capacitive sensing of droplets for microfluidic devices based on thermocapillary actuation

OpenAIRE

Chen, Jian Z.; Darhuber, Anton A.; Troian, Sandra M.; Wagner, Sigurd

2004-01-01

The design and performance of a miniaturized coplanar capacitive sensor is presented whose electrode arrays can also function as resistive microheaters for thermocapillary actuation of liquid films and droplets. Optimal compromise between large capacitive signal and high spatial resolution is obtained for electrode widths comparable to the liquid film thickness measured, in agreement with supporting numerical simulations which include mutual capacitance effects. An interdigitated, variable wi...

Photonic characterization of capacitance-voltage characteristics in MOS capacitors and current-voltage characteristics in MOSFETs

International Nuclear Information System (INIS)

Kim, H. C.; Kim, H. T.; Cho, S. D.; Song, S. J.; Kim, Y. C.; Kim, S. K.; Chi, S. S.; Kim, D. J.; Kim, D. M.

2002-01-01

Based on the photonic high-frequency capacitance-voltage (HF-CV) response of MOS capacitors, a new characterization method is reported for the analysis of interface states in MOS systems. An optical source with a photonic energy less than the silicon band-gap energy (hv g ) is employed for the photonic HF-CV characterization of interface states distributed in the photoresponsive energy band (E C - hv t C ). If a uniform distribution of trap levels is assumed, the density of interface states (D it ) in the photoresponsive energy band of MOS capacitors, characterized by the new photonic HF-CV method, was observed to be D it = 1 ∼ 5 x 10 11 eV -1 cm -2 . Photonic current-voltage characteristics (I D - V GS , V DS ) of MOSFETs, which are under control of the photoconductive and the photovoltaic effects, are also investigated under optical illumination

The detector response simulation for the CBM silicon tracking system as a tool for hit error estimation

Energy Technology Data Exchange (ETDEWEB)

Malygina, Hanna [Goethe Universitaet Frankfurt (Germany); KINR, Kyiv (Ukraine); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Friese, Volker; Zyzak, Maksym [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Darmstadt (Germany); Collaboration: CBM-Collaboration

2016-07-01

The Compressed Baryonic Matter experiment(CBM) at FAIR is designed to explore the QCD phase diagram in the region of high net-baryon densities. As the central detector component, the Silicon Tracking System (STS) is based on double-sided micro-strip sensors. To achieve realistic modelling, the response of the silicon strip sensors should be precisely included in the digitizer which simulates a complete chain of physical processes caused by charged particles traversing the detector, from charge creation in silicon to a digital output signal. The current implementation of the STS digitizer comprises non-uniform energy loss distributions (according to the Urban theory), thermal diffusion and charge redistribution over the read-out channels due to interstrip capacitances. Using the digitizer, one can test an influence of each physical processes on hit error separately. We have developed a new cluster position finding algorithm and a hit error estimation method for it. Estimated errors were verified by the width of pull distribution (expected to be about unity) and its shape.

Evaluation of the bulk and strip characteristics of large area n-in-p silicon sensors intended for a very high radiation environment

Czech Academy of Sciences Publication Activity Database

Böhm, Jan; Mikeštíková, Marcela; Affolder, A.A.; Allport, P.P.; Bates, R.; Betancourt, C.; Brown, H.; Buttar, C.; Carter, J. R.; Casse, G.

2011-01-01

Roč. 636, č. 1 (2011), "S104"-"S110" ISSN 0168-9002 R&D Projects: GA MŠk LA08032 Institutional research plan: CEZ:AV0Z10100502 Keywords : silicon * micro-strip * ATLAS ID upgrade * SLHC * leakage current * depletion voltage * electrical characteristics * coupling capacitance Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.207, year: 2011 http://dx.doi.org/10.1016/j.nima.2010.04.093

3D printed biomimetic whisker-based sensor with co-planar capacitive sensing

NARCIS (Netherlands)

Delamare, John; Sanders, Remco G.P.; Krijnen, Gijsbertus J.M.

2016-01-01

This paper describes the development of a whisker sensor for tactile purposes and which is fabricated by 3D printing. Read-out consists of a capacitive measurement of a co-planar capacitance which is affected by a dielectric that is driven into the electric field of the capacitance. The current

Capacitance-voltage characteristics of GaAs ion-implanted structures

Directory of Open Access Journals (Sweden)

Privalov E. N.

2008-08-01

Full Text Available A noniterative numerical method is proposed to calculate the barrier capacitance of GaAs ion-implanted structures as a function of the Schottky barrier bias. The features of the low- and high-frequency capacitance-voltage characteristics of these structures which are due to the presence of deep traps are elucidated.

A new recontruction algorithm for use with capacitance-based tomography

Directory of Open Access Journals (Sweden)

Ø. Isaksen

1994-01-01

Full Text Available A new reconstruction algorithm for use with capacitance-based process tomography is proposed. A numerical simulator, capable of calculating the capacitances for a particular sensor configuration and flow regime is used together with a parameter representation of the dielectric distribution and an optimization algorithm. The algorithm calculates these parameters and hence the dielectric distribution, by minimizing a function defined as a weighted sum of square differences between the measured and estimated capacitances. The method is tested by using both synthetic and experimental data, and the results are compared with results from the commonly used Linear Back Projection (LBP algorithm. The method is capable of obtaining the correct parameter values for all the flow regimes tested, and does provide a better estimate than the LBP method. The method proves to be very promising, and is a step towards quantitative capacitance tomography.

Preparation and electrochemical capacitance performances of super-hydrophilic conducting polyaniline

Energy Technology Data Exchange (ETDEWEB)

Li, Xingwei; Li, Xiaohan; Dai, Na; Wang, Gengchao; Wang, Zhun [Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Meilong Road 130, Shanghai 200237 (China)

2010-08-15

Super-hydrophilic conducting polyaniline was prepared by surface modification of polyaniline using tetraethyl orthosilicate in water/ethanol solution, whereas its conductivity was 4.16 S cm{sup -1} at 25 C. And its electrochemical capacitance performances as an electrode material were evaluated by the cyclic voltammetry and galvanostatic charge/discharge test in 0.1 M H{sub 2}SO{sub 4} aqueous solution. Its initial specific capacitance was 500 F g{sup -1} at a constant current density of 1.5 A g{sup -1}, and the capacitance still reached about 400 F g{sup -1} after 5000 consecutive cycles. Moreover, its capacitance retention ratio was circa 70% with the growth of current densities from 1.5 to 20 A g{sup -1}, indicating excellent rate capability. It would be a promising electrode material for aqueous redox supercapacitors. (author)

Análisis mecánico por elementos finitos de una antena UHF en la órbita de Marte

OpenAIRE

Moreno García, Carlos

2015-01-01

El proyecto desarrolla el diseño mecánico de una antena helicoidal en banda UHF que será parte de un satélite cuyo destino final será Marte. Los principales objetivos de la misión son: Buscar trazas o evidencia de metano y otros gases atmosféricos que podrían manifestar signos de procesos biológicos o geológicos activos, es decir, buscar indicios de vida pasada en Marte Poner a prueba la tecnología necesaria para posteriores misiones europeas a Marte. El proyecto se centrará en la...

Effect of Plasma Membrane Semipermeability in Making the Membrane Electric Double Layer Capacitances Significant.

Science.gov (United States)

Sinha, Shayandev; Sachar, Harnoor Singh; Das, Siddhartha

2018-01-30

Electric double layers (or EDLs) formed at the membrane-electrolyte interface (MEI) and membrane-cytosol interface (MCI) of a charged lipid bilayer plasma membrane develop finitely large capacitances. However, these EDL capacitances are often much larger than the intrinsic capacitance of the membrane, and all of these capacitances are in series. Consequently, the effect of these EDL capacitances in dictating the overall membrane-EDL effective capacitance C eff becomes negligible. In this paper, we challenge this conventional notion pertaining to the membrane-EDL capacitances. We demonstrate that, on the basis of the system parameters, the EDL capacitance for both the permeable and semipermeable membranes can be small enough to influence C eff . For the semipermeable membranes, however, this lowering of the EDL capacitance can be much larger, ensuring a reduction of C eff by more than 20-25%. Furthermore, for the semipermeable membranes, the reduction in C eff is witnessed over a much larger range of system parameters. We attribute such an occurrence to the highly nonintuitive electrostatic potential distribution associated with the recently discovered phenomena of charge-inversion-like electrostatics and the attainment of a positive zeta potential at the MCI for charged semipermeable membranes. We anticipate that our findings will impact the quantification and the identification of a large number of biophysical phenomena that are probed by measuring the plasma membrane capacitance.

Three-dimensional supercapacitors composed of Ba{sub 0.65}Sr{sub 0.35}TiO{sub 3} (BST)/NiSi{sub 2}/silicon microchannel plates

Energy Technology Data Exchange (ETDEWEB)

Liu Tao; Zhang Huayan; Wang Fei; Shi Jing; Ci Pengliang [Laboratory of Polar Materials and Devices, Ministry of Education, and Department of Electronic Engineering, East China Normal University, 500 Dongchuan Road, Minhang District, Shanghai 200241 (China); Wang Lianwei, E-mail: lwwang@ee.ecnu.edu.cn [Laboratory of Polar Materials and Devices, Ministry of Education, and Department of Electronic Engineering, East China Normal University, 500 Dongchuan Road, Minhang District, Shanghai 200241 (China); Ge Shuli; Wang Qingjiang [Department of Chemistry, East China Normal University, Shanghai 200241 (China); Chu, Paul K. [Department of Physics and Material Sciences, City University of Hong Kong, Tat Chee Avenue, Kowloon (Hong Kong)

2011-03-25

Three-dimensional (3D) supercapacitors consisting of Ba{sub 0.65}Sr{sub 0.35}TiO{sub 3} (BST)/NiSi{sub 2}/silicon microchannel plate (MCP) stacked structure have been fabricated. The silicon MCP produced by electrochemical etching is utilized as a backbone of the 3D structure on which a nickel silicide current collector layer and Ba{sub 0.65}Sr{sub 0.35}TiO{sub 3} dielectric layer are deposited successively by electroless plating and the sol-gel method, respectively. The morphology and structure of the 3D BST/NiSi{sub 2}/Si-MCP structure are characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD) and the electrochemical properties are determined by cyclic voltammetry (CV) and chronopotentiometry. The structure exhibits excellent capacitive behavior with a maximum capacitance of 784 F g{sup -1}. After 700 charging/discharging cycles, the C{sub f} decreases slightly with only a 5.7% loss and is stable after more than 700 cycles. The BST/NiSi{sub 2}/Si-MCP 3D structure is a potential supercapacitor in industrial applications.

Density Functional Theory Calculations of the Quantum Capacitance of Graphene Oxide as a Supercapacitor Electrode.

Science.gov (United States)

Song, Ce; Wang, Jinyan; Meng, Zhaoliang; Hu, Fangyuan; Jian, Xigao

2018-03-31

Graphene oxide has become an attractive electrode-material candidate for supercapacitors thanks to its higher specific capacitance compared to graphene. The quantum capacitance makes relative contributions to the specific capacitance, which is considered as the major limitation of graphene electrodes, while the quantum capacitance of graphene oxide is rarely concerned. This study explores the quantum capacitance of graphene oxide, which bears epoxy and hydroxyl groups on its basal plane, by employing density functional theory (DFT) calculations. The results demonstrate that the total density of states near the Fermi level is significantly enhanced by introducing oxygen-containing groups, which is beneficial for the improvement of the quantum capacitance. Moreover, the quantum capacitances of the graphene oxide with different concentrations of these two oxygen-containing groups are compared, revealing that more epoxy and hydroxyl groups result in a higher quantum capacitance. Notably, the hydroxyl concentration has a considerable effect on the capacitive behavior. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Nonlinear dynamics of capacitive charging and desalination by porous electrodes

NARCIS (Netherlands)

Biesheuvel, P.M.; Bazant, M.Z.

2010-01-01

The rapid and efficient exchange of ions between porous electrodes and aqueous solutions is important in many applications, such as electrical energy storage by supercapacitors, water desalination and purification by capacitive deionization, and capacitive extraction of renewable energy from a

A Review of High Voltage Drive Amplifiers for Capacitive Actuators

DEFF Research Database (Denmark)

Huang, Lina; Zhang, Zhe; Andersen, Michael A. E.

2012-01-01

This paper gives an overview of the high voltage amplifiers, which are used to drive capacitive actuators. The amplifiers for both piezoelectric and DEAP (dielectric electroactive polymer) actuator are discussed. The suitable topologies for driving capacitive actuators are illustrated in detail...

Capacitance Regression Modelling Analysis on Latex from Selected Rubber Tree Clones

International Nuclear Information System (INIS)

Rosli, A D; Baharudin, R; Hashim, H; Khairuzzaman, N A; Mohd Sampian, A F; Abdullah, N E; Kamaru'zzaman, M; Sulaiman, M S

2015-01-01

This paper investigates the capacitance regression modelling performance of latex for various rubber tree clones, namely clone 2002, 2008, 2014 and 3001. Conventionally, the rubber tree clones identification are based on observation towards tree features such as shape of leaf, trunk, branching habit and pattern of seeds texture. The former method requires expert persons and very time-consuming. Currently, there is no sensing device based on electrical properties that can be employed to measure different clones from latex samples. Hence, with a hypothesis that the dielectric constant of each clone varies, this paper discusses the development of a capacitance sensor via Capacitance Comparison Bridge (known as capacitance sensor) to measure an output voltage of different latex samples. The proposed sensor is initially tested with 30ml of latex sample prior to gradually addition of dilution water. The output voltage and capacitance obtained from the test are recorded and analyzed using Simple Linear Regression (SLR) model. This work outcome infers that latex clone of 2002 has produced the highest and reliable linear regression line with determination coefficient of 91.24%. In addition, the study also found that the capacitive elements in latex samples deteriorate if it is diluted with higher volume of water. (paper)

Capacitive Imaging For Skin Characterization and Solvent Penetration

OpenAIRE

Xiao, P; Zhang, X; Bontozoglou, C

2016-01-01

Capacitive contact imaging has shown potential in measuring skin properties including hydration, micro relief analysis, as well as solvent penetration measurements . Through calibration we can also measure the absolute permittivity of the skin, and from absolute permittivity we then work out the absolute water content (or solvent content) in skin. In this paper, we present our latest study of capacitive contact imaging for skin characterization, i.e. skin hydration and skin damages etc. The r...

Introducing radiality constraints in capacitated location-routing problems

Directory of Open Access Journals (Sweden)

Eliana Mirledy Toro Ocampo

2017-03-01

Full Text Available In this paper, we introduce a unified mathematical formulation for the Capacitated Vehicle Routing Problem (CVRP and for the Capacitated Location Routing Problem (CLRP, adopting radiality constraints in order to guarantee valid routes and eliminate subtours. This idea is inspired by formulations already employed in electric power distribution networks, which requires a radial topology in its operation. The results show that the proposed formulation greatly improves the convergence of the solver.

Time-dependent resonant UHF CI approach for the photo-induced dynamics of the multi-electron system confined in 2D QD

Energy Technology Data Exchange (ETDEWEB)

Okunishi, Takuma; Clark, Richard; Takeda, Kyozaburo [Waseda University, Tokyo 169-8555 (Japan); Kusakabe, Kouichi [Osaka University, Osaka 560-8531 (Japan); Tomita, Norikazu [Yamagata University, Yamagata 960-8560 (Japan)

2013-12-04

We extend the static multi-reference description (resonant UHF) to the dynamic system in order to include the correlation effect over time, and simplify the TD Schrödinger equation (TD-CI) into a time-developed rate equation where the TD external field Ĥ′(t) is then incorporated directly in the Hamiltonian without any approximations. We apply this TD-CI method to the two-electron ground state of a 2D quantum dot (QD) under photon injection and study the resulting two-electron Rabi oscillation.

A novel approach for osteocalcin detection by competitive ELISA using porous silicon as a substrate.

Science.gov (United States)

Rahimi, Fereshteh; Mohammadnejad Arough, Javad; Yaghoobi, Mona; Davoodi, Hadi; Sepehri, Fatemeh; Amirabadizadeh, Masood

2017-11-01

In this study, porous silicon (PSi) was utilized instead of prevalent polystyrene platforms, and its capability in biomolecule screening was examined. Here, two types of porous structure, macroporous silicon (Macro-PSi) and mesoporous silicon (Meso-PSi), were produced on silicon wafers by electrochemical etching using different electrolytes. Moreover, both kinds of fresh and oxidized PSi samples were investigated. Next, osteocalcin as a biomarker of the bone formation process was used as a model biomarker, and the colorimetric detection was performed by competitive enzyme-linked immunosorbent assay (ELISA). Both Macro-PSi and Meso-PSi substrates in the oxidized state, specifically the Meso-porous structure, were reported to have higher surface area to volume ratio, more capacitance of surface-antigen interaction, and more ability to capture antigen in comparison with the prevalent platforms. Moreover, the optical density signal of osteocalcin detected by the ELISA technique was notably higher than the common platforms. Based on the findings of this study, PSi can potentially be used in the ELISA to achieve better results and consequently more sensitivity. A further asset of incorporating such a nanometer structure in the ELISA technique is that the system response to analyte concentration could be maintained by consuming lower monoclonal antibody (or antigen) and consequently reduces the cost of the experiment. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

Quantum decrease of capacitance in a nanometer-sized tunnel junction

Science.gov (United States)

Untiedt, C.; Saenz, G.; Olivera, B.; Corso, M.; Sabater, C.; Pascual, J. I.

2013-03-01

We have studied the capacitance of the tunnel junction defined by the tip and sample of a Scanning Tunnelling Microscope through the measurement of the electrostatic forces and impedance of the junction. A decrease of the capacitance when a tunnel current is present has shown to be a more general phenomenon as previously reported in other systems. On another hand, an unexpected reduction of the capacitance is also observed when increasing the applied voltage above the work function energy of the electrodes to the Field Emission (FE) regime, and the decrease of capacitance due to a single FE-Resonance has been characterized. All these effects should be considered when doing measurements of the electronic characteristics of nanometer-sized electronic devices and have been neglected up to date. Spanish government (FIS2010-21883-C02-01, CONSOLIDER CSD2007-0010), Comunidad Valenciana (ACOMP/2012/127 and PROMETEO/2012/011)

A new capacitive/resistive probe method for studying magnetic surfaces

International Nuclear Information System (INIS)

Kitajima, Sumio; Takayama, Masakazu; Zama, Tatsuya; Takaya, Kazuhiro; Takeuchi, Nobunao; Watanabe, Hiroshige

1991-01-01

A new capacitive/resistive probe method for mapping the magnetic surfaces from resistance or capacitance between a magnetic surface and a vacuum vessel was developed and tested. Those resistances and capacitances can be regarded as components of a simple electrical bridge circuit. This method exploits electrical transient response of the bridge circuit for a square pulse. From equiresistance or equicapacitance points, the magnetic surface structure can be deduced. Measurements on the Tohoku University Heliac, which is a small-size standard heliac, show good agreement with numerical calculations. This method is particularly useful for pulse-operated machines. (author)

Investigation of carrier removal in electron irradiated silicon diodes

International Nuclear Information System (INIS)

Taylor, S.J.; Yamaguchi, M.; Matsuda, S.; Hisamatsu, T.; Kawasaki, O.

1997-01-01

We present a detailed study of n + p p + silicon diodes irradiated with fluences of 1 MeV electrons high enough to cause device failure due to majority carrier removal. Capacitance voltage (C V) measurements were used to monitor the change in the carrier concentration of the base of the device as a function of radiation fluence. These were compared to the defect spectra in the same region obtained by deep level transient spectroscopy, and to the current voltage characteristics of the device, both before and after annealing. We observed the expected deep levels with activation energies of 0.18 and 0.36 eV, but the C endash V results imply that other trap levels must play a more important role in the carrier removal process. copyright 1997 American Institute of Physics

Enhanced Capacitance of Hybrid Layered Graphene/Nickel Nanocomposite for Supercapacitors

Science.gov (United States)

Mohd Zaid, Norsaadatul Akmal; Idris, Nurul Hayati

2016-08-01

In this work, Ni nanoparticles were directly decorated on graphene (G) nanosheets via mechanical ball milling. Based on transmission electron microscopy observations, the Ni nanoparticles were well dispersed and attached to the G nanosheet without any agglomerations. Electrochemical results showed that the capacitance of a G/Ni nanocomposite was 275 F g-1 at a current density of 2 A g-1, which is higher than the capacitance of bare G (145 F g-1) and bare Ni (3 F g-1). The G/Ni electrode also showed superior performance at a high current density, exhibiting a capacitance of 190 F g-1 at a current density of 5 A g-1 and a capacitance of 144 F g-1 at a current density of 10 A g-1. The equivalent series resistance for G/Ni nanocomposites also decreased. The enhanced performance of this hybrid supercapacitor is best described by the synergistic effect, i.e. dual charge-storage mechanism, which is demonstrated by electrical double layer and pseudocapacitance materials. Moreover, a high specific surface area and electrical conductivity of the materials enhanced the capacitance. These results indicate that the G/Ni nanocomposite is a potential supercapacitor.

New Type Multielectrode Capacitance Sensor for Liquid Level

Energy Technology Data Exchange (ETDEWEB)

Zhao, Y R [China University of Petroleum (Huadong), Qingdao (China); Shi, A P [Shandong University of Science and Technology, Qingdao (China); Chen, G Q [Shandong University of Science and Technology, Qingdao (China); Chang, Y Y [Shandong University of Science and Technology, Qingdao (China); Hang, Z [Shandong University of Science and Technology, Qingdao (China); Liu, B M [Binzhou University, Binzhou (China)

2006-10-15

This paper introduces the design of a new type multielectrode capacitance sensor for liquid level. The system regards electric field sensor MC33794 as the core and applies microcontroller MC9S12DJ128 to realize intelligent liquid level monitoring system, which overcomes the disadvantages of the traditional capacitance sensor, improves on the anti-jamming ability and the measurement precision and simplifies the system structure. Finally, the paper sums up the design of the system.

X-ray radiation damage studies and design of a silicon pixel sensor for science at the XFEL

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jiaguo

2013-06-15

Experiments at the European X-ray Free Electron Laser (XFEL) require silicon pixel sensors which can withstand X-ray doses up to 1 GGy. For the investigation of Xray radiation damage up to these high doses, MOS capacitors and gate-controlled diodes built on high resistivity n-doped silicon with crystal orientations left angle 100 right angle and left angle 111 right angle produced by four vendors, CiS, Hamamatsu, Canberra and Sintef have been irradiated with 12 keV X-rays at the DESY DORIS III synchrotron-light source. Using capacitance/ conductance-voltage, current-voltage and thermal dielectric relaxation current measurements, the densities of oxide charges and interface traps at the Si-SiO{sub 2} interface, and the surface-current densities have been determined as function of dose. Results indicate that the dose dependence of the oxide-charge density, the interface-trap density and the surface-current density depend on the crystal orientation and producer. In addition, the influence of the voltage applied to the gates of the MOS capacitor and the gate-controlled diode during X-ray irradiation on the oxide-charge density, the interface-trap density and the surface-current density has been investigated at doses of 100 kGy and 100 MGy. It is found that both strongly depend on the gate voltage if the electric field in the oxide points from the surface of the SiO{sub 2} to the Si-SiO{sub 2} interface. To verify the long-term stability of irradiated silicon sensors, annealing studies have been performed at 60 C and 80 C on MOS capacitors and gate-controlled diodes irradiated to 5 MGy as well, and the annealing kinetics of oxide charges and surface current were determined. Moreover, the macroscopic electrical properties of segmented sensors have slao been investigated as function of dose. It is found that the defects introduced by X-rays increase the full depletion voltage, the surface leakage current and the inter-electrode capacitance of the segmented sensor. An

X-ray radiation damage studies and design of a silicon pixel sensor for science at the XFEL

International Nuclear Information System (INIS)

Zhang, Jiaguo

2013-06-01

Experiments at the European X-ray Free Electron Laser (XFEL) require silicon pixel sensors which can withstand X-ray doses up to 1 GGy. For the investigation of Xray radiation damage up to these high doses, MOS capacitors and gate-controlled diodes built on high resistivity n-doped silicon with crystal orientations left angle 100 right angle and left angle 111 right angle produced by four vendors, CiS, Hamamatsu, Canberra and Sintef have been irradiated with 12 keV X-rays at the DESY DORIS III synchrotron-light source. Using capacitance/ conductance-voltage, current-voltage and thermal dielectric relaxation current measurements, the densities of oxide charges and interface traps at the Si-SiO 2 interface, and the surface-current densities have been determined as function of dose. Results indicate that the dose dependence of the oxide-charge density, the interface-trap density and the surface-current density depend on the crystal orientation and producer. In addition, the influence of the voltage applied to the gates of the MOS capacitor and the gate-controlled diode during X-ray irradiation on the oxide-charge density, the interface-trap density and the surface-current density has been investigated at doses of 100 kGy and 100 MGy. It is found that both strongly depend on the gate voltage if the electric field in the oxide points from the surface of the SiO 2 to the Si-SiO 2 interface. To verify the long-term stability of irradiated silicon sensors, annealing studies have been performed at 60 C and 80 C on MOS capacitors and gate-controlled diodes irradiated to 5 MGy as well, and the annealing kinetics of oxide charges and surface current were determined. Moreover, the macroscopic electrical properties of segmented sensors have slao been investigated as function of dose. It is found that the defects introduced by X-rays increase the full depletion voltage, the surface leakage current and the inter-electrode capacitance of the segmented sensor. An electron

Detecting size and shape of bodies capacitatively

International Nuclear Information System (INIS)

Walton, H.

1980-01-01

The size and shape of a body is determined by rolling it between the plates of capacitors and measuring the capacitance changes. A capacitor comprising two parallel, spaced wires inclined to the rolling direction and above and below the rolling body scans sections of the body along its longitudinal axis, another determines the body's lengths and a third comprising two non-parallel wires determines the position of the body. The capacitance changes are compared with those produced by a body of known size and shape so that the size and shape of the body can be determined. (author)

Classic and Quantum Capacitances in Bernal Bilayer and Trilayer Graphene Field Effect Transistor

Directory of Open Access Journals (Sweden)

Hatef Sadeghi

2013-01-01

Full Text Available Our focus in this study is on characterizing the capacitance voltage (C-V behavior of Bernal stacking bilayer graphene (BG and trilayer graphene (TG as the channel of FET devices. The analytical models of quantum capacitance (QC of BG and TG are presented. Although QC is smaller than the classic capacitance in conventional devices, its contribution to the total metal oxide semiconductor capacitor in graphene-based FET devices becomes significant in the nanoscale. Our calculation shows that QC increases with gate voltage in both BG and TG and decreases with temperature with some fluctuations. However, in bilayer graphene the fluctuation is higher due to its tunable band structure with external electric fields. In similar temperature and size, QC in metal oxide BG is higher than metal oxide TG configuration. Moreover, in both BG and TG, total capacitance is more affected by classic capacitance as the distance between gate electrode and channel increases. However, QC is more dominant when the channel becomes thinner into the nanoscale, and therefore we mostly deal with quantum capacitance in top gate in contrast with bottom gate that the classic capacitance is dominant.

Contamination of current-clamp measurement of neuron capacitance by voltage-dependent phenomena

Science.gov (United States)

White, William E.

2013-01-01

Measuring neuron capacitance is important for morphological description, conductance characterization, and neuron modeling. One method to estimate capacitance is to inject current pulses into a neuron and fit the resulting changes in membrane potential with multiple exponentials; if the neuron is purely passive, the amplitude and time constant of the slowest exponential give neuron capacitance (Major G, Evans JD, Jack JJ. Biophys J 65: 423–449, 1993). Golowasch et al. (Golowasch J, Thomas G, Taylor AL, Patel A, Pineda A, Khalil C, Nadim F. J Neurophysiol 102: 2161–2175, 2009) have shown that this is the best method for measuring the capacitance of nonisopotential (i.e., most) neurons. However, prior work has not tested for, or examined how much error would be introduced by, slow voltage-dependent phenomena possibly present at the membrane potentials typically used in such work. We investigated this issue in lobster (Panulirus interruptus) stomatogastric neurons by performing current clamp-based capacitance measurements at multiple membrane potentials. A slow, voltage-dependent phenomenon consistent with residual voltage-dependent conductances was present at all tested membrane potentials (−95 to −35 mV). This phenomenon was the slowest component of the neuron's voltage response, and failure to recognize and exclude it would lead to capacitance overestimates of several hundredfold. Most methods of estimating capacitance depend on the absence of voltage-dependent phenomena. Our demonstration that such phenomena make nonnegligible contributions to neuron responses even at well-hyperpolarized membrane potentials highlights the critical importance of checking for such phenomena in all work measuring neuron capacitance. We show here how to identify such phenomena and minimize their contaminating influence. PMID:23576698

Lightweight linear alternators with and without capacitive tuning

Science.gov (United States)

Niedra, Janis M.

1993-06-01

Permanent magnet excited linear alternators rated tens of kW and coupled to free-piston Stirling engines are presently viewed as promising candidates for long term generation of electric power in both space and terrestrial applications. Series capacitive cancellation of the internal inductive reactance of such alternators was considered a viable way to both increase power extraction and to suppress unstable modes of the thermodynamic oscillation. Idealized toroidal and cylindrical alternator geometries are used for a comparative study of the issues of specific mass and capacitive tuning, subject to stability criteria. The analysis shows that the stator mass of an alternator designed to be capacitively tuned is always greater than the minimum achievable stator mass of an alternator designed with no capacitors, assuming equal utilization of materials ratings and the same frequency and power to a resistive load. This conclusion is not substantially altered when the usually lesser masses of the magnets and of any capacitors are added. Within the reported stability requirements and under circumstances of normal materials ratings, this study finds no clear advantage to capacitive tuning. Comparative plots of the various constituent masses are presented versus the internal power factor taken as a design degree of freedom. The explicit formulas developed for stator core, coil, capacitor, and magnet masses and for the degree of magnet utilization provide useful estimates of scaling effects.

Mechanical strain can switch the sign of quantum capacitance from positive to negative.

Science.gov (United States)

Hanlumyuang, Yuranan; Li, Xiaobao; Sharma, Pradeep

2014-11-14

Quantum capacitance is a fundamental quantity that can directly reveal many-body interactions among electrons and is expected to play a critical role in nanoelectronics. One of the many tantalizing recent physical revelations about quantum capacitance is that it can possess a negative value, hence allowing for the possibility of enhancing the overall capacitance in some particular material systems beyond the scaling predicted by classical electrostatics. Using detailed quantum mechanical simulations, we found an intriguing result that mechanical strains can tune both signs and values of quantum capacitance. We used a small coaxially gated carbon nanotube as a paradigmatical capacitor system and showed that, for the range of mechanical strain considered, quantum capacitance can be adjusted from very large positive to very large negative values (in the order of plus/minus hundreds of attofarads), compared to the corresponding classical geometric value (0.31035 aF). This finding opens novel avenues in designing quantum capacitance for applications in nanosensors, energy storage, and nanoelectronics.

Tailoring design and fabrication of capacitive RF MEMS switches for K-band applications

Science.gov (United States)

Quaranta, Fabio; Persano, Anna; Capoccia, Giovanni; Taurino, Antonietta; Cola, Adriano; Siciliano, Pietro; Lucibello, Andrea; Marcelli, Romolo; Proietti, Emanuela; Bagolini, Alvise; Margesin, Benno; Bellutti, Pierluigi; Iannacci, Jacopo

2015-05-01

Shunt capacitive radio-frequency microelectromechanical (RF MEMS) switches were modelled, fabricated and characterized in the K-band domain. Design allowed to predict the RF behaviour of the switches as a function of the bridge geometric parameters. The modelled switches were fabricated on silicon substrate, using a surface micromachining approach. In addition to the geometric parameters, the material structure in the bridge-actuator area was modified for switches fabricated on the same wafer, thanks to the removal/addition of two technological steps of crucial importance for RF MEMS switches performance, which are the use of the sacrificial layer and the deposition of a floating metal layer on the actuator. Surface profilometry analysis was used to check the material layer structure in the different regions of the bridge area as well as to investigate the mechanical behaviour of the moveable bridge under the application of a loaded force. The RF behaviour of all the fabricated switches was measured, observing the impact on the isolation of the manipulation of the bridge size and of the variations in the fabrication process.

Design of a passive UHF RFID tag for the ISO18000-6C protocol

Energy Technology Data Exchange (ETDEWEB)

Wang Yao; Wen Guangjun; Mao Wei; He Yanli; Zhu Xueyong, E-mail: wangyao220597@yahoo.com.cn [RFIC Laboratory CICS, School of Communication and Information Engineering, University of Electronic Science and Technology of China, Chengdu 611731 (China)

2011-05-15

This paper presents a new fully integrated wide-range UHF passive RFID tag chip design that is compatible with the ISO18000-6C protocol. In order to reduce the die area, an ultra-low power CMOS voltage regulator without resistors and an area-efficient amplitude shift keying demodulator with a novel adaptive average generator are both adopted. A low power clock generator is designed to guarantee the accuracy of the clock under {+-}4%. As the clock gating technology is employed to reduce the power consumption of the baseband processor, the total power consumption of the tag is about 14 {mu}W with a sensitivity of -9.5 dBm. The detection distance can reach about 5 m under 4 W effective isotropic radiated power. The whole tag is fabricated in TSMC 0.18 {mu}m CMOS technology and the chip size is 880 x 880 {mu}m{sup 2}. (semiconductor integrated circuits)

Design of a passive UHF RFID tag for the ISO18000-6C protocol

International Nuclear Information System (INIS)

Wang Yao; Wen Guangjun; Mao Wei; He Yanli; Zhu Xueyong

2011-01-01

This paper presents a new fully integrated wide-range UHF passive RFID tag chip design that is compatible with the ISO18000-6C protocol. In order to reduce the die area, an ultra-low power CMOS voltage regulator without resistors and an area-efficient amplitude shift keying demodulator with a novel adaptive average generator are both adopted. A low power clock generator is designed to guarantee the accuracy of the clock under ±4%. As the clock gating technology is employed to reduce the power consumption of the baseband processor, the total power consumption of the tag is about 14 μW with a sensitivity of -9.5 dBm. The detection distance can reach about 5 m under 4 W effective isotropic radiated power. The whole tag is fabricated in TSMC 0.18 μm CMOS technology and the chip size is 880 x 880 μm 2 . (semiconductor integrated circuits)

Coplanar UHF RFID tag antenna with U-shaped inductively coupled feed for metallic applications.

Directory of Open Access Journals (Sweden)

Karrar Naji Salman

Full Text Available In this paper, we present a novel compact, coplanar, tag antenna design for metallic objects. Electrically small antenna has designed for a UHF RFID (860-960 MHz based on a proximity-coupled feed through. Furthermore, two symmetrical Via-loaded coplanar grounds fed by a U-shaped inductively coupled feed through an embedded transmission line. This configuration results in an antenna with dimensions of 31 × 19.5 × 3.065 mm3 at 915 MHz, and the total gain for the antenna is 0.12 dBi. The Via-loaded coplanar and U-shaped inductively coupled feeds allow the antenna to provide flexible tuning in terms of antenna impedance. In addition, a figure of merit is applied for the proposed tag antenna, and the results are presented. The read range is measured to be 4.2 m, which is very close to simulated values. This antenna measurement shows very good agreement with simulations.

Enhancing the power output of the VA-955 UHF-TV klystron

International Nuclear Information System (INIS)

Bowen, O.N.; Lawson, J.Q.

1977-01-01

The Varian VA-955 UHF-TV klystron is rated at 50 kW CW, and four of these klystrons were used to provide 200 kW of RF power for lower hybrid heating experiments on the ATC machine at 800 MHz. These proven, production-type tubes were wanted to generate more power for larger type machines, such as the PDX. Varian was asked whether the tubes were capable of higher-power operation in pulsed applications. They replied that they had no experimental data but felt that the tubes were capable of greatly enhanced performance under pulsed conditions. By using cathode modulation instead of modulating anode control of the klystron, and thus limiting the time that high voltage is applied to the cathode, it was shown that the tube is capable of an output power of 200 kW for tens of milliseconds compared to its normal CW rating of 50 kW. A description is given of the experimental results, the required modifications to the klystron and output transmission circuit, the details of operation of the regulating modulator used to perform the experiment. Upgrade kits are now being fabricated to allow 200 kW operation of the two 50 kW units which were lent to General Atomic for Doublet II experiments

Atomic Layer Deposition Alumina-Passivated Silicon Nanowires: Probing the Transition from Electrochemical Double-Layer Capacitor to Electrolytic Capacitor.

Science.gov (United States)

Gaboriau, Dorian; Boniface, Maxime; Valero, Anthony; Aldakov, Dmitry; Brousse, Thierry; Gentile, Pascal; Sadki, Said

2017-04-19

Silicon nanowires were coated by a 1-5 nm thin alumina layer by atomic layer deposition (ALD) in order to replace poorly reproducible and unstable native silicon oxide by a highly conformal passivating alumina layer. The surface coating enabled probing the behavior of symmetric devices using such electrodes in the EMI-TFSI electrolyte, allowing us to attain a large cell voltage up to 6 V in ionic liquid, together with very high cyclability with less than 4% capacitance fade after 10 6 charge/discharge cycles. These results yielded fruitful insights into the transition between an electrochemical double-layer capacitor behavior and an electrolytic capacitor behavior. Ultimately, thin ALD dielectric coatings can be used to obtain hybrid devices exhibiting large cell voltage and excellent cycle life of dielectric capacitors, while retaining energy and power densities close to the ones displayed by supercapacitors.

Negative quantum capacitance induced by midgap states in single-layer graphene.

Science.gov (United States)

Wang, Lin; Wang, Yang; Chen, Xiaolong; Zhu, Wei; Zhu, Chao; Wu, Zefei; Han, Yu; Zhang, Mingwei; Li, Wei; He, Yuheng; Xiong, Wei; Law, Kam Tuen; Su, Dangsheng; Wang, Ning

2013-01-01

We demonstrate that single-layer graphene (SLG) decorated with a high density of Ag adatoms displays the unconventional phenomenon of negative quantum capacitance. The Ag adatoms act as resonant impurities and form nearly dispersionless resonant impurity bands near the charge neutrality point (CNP). Resonant impurities quench the kinetic energy and drive the electrons to the Coulomb energy dominated regime with negative compressibility. In the absence of a magnetic field, negative quantum capacitance is observed near the CNP. In the quantum Hall regime, negative quantum capacitance behavior at several Landau level positions is displayed, which is associated with the quenching of kinetic energy by the formation of Landau levels. The negative quantum capacitance effect near the CNP is further enhanced in the presence of Landau levels due to the magnetic-field-enhanced Coulomb interactions.

The interfacial capacitance of an oxidised polycrystalline gold electrode in an aqueous HClO4 electrolyte

International Nuclear Information System (INIS)

Grdeń, M.

2013-01-01

The interfacial capacitance of a polycrystalline gold electrode electrochemically oxidised in an aqueous 0.1 M HClO 4 electrolyte has been investigated by means of the electrochemical impedance spectroscopy. From 1.3 to 3 monolayers of Au atoms were oxidised under constant potential conditions and for various oxidation times. The capacitance of the oxidised layers was analysed as a function of the electrode potential and the extent of the surface oxidation. It was found that the interfacial capacitance decreases upon surface oxidation. The components of the interfacial capacitance of the oxidised layer: the double layer capacitance and the capacitance of the oxidised layer; have been separated. The capacitance of the double layer of the oxidised surface was found to be comparable to the capacitance measured for the metallic surface. - Highlights: • The impedance spectra for thin layers of Au oxides/hydroxides were acquired. • Separate determination of the double layer and the oxide capacitances of oxidised Au • The double layer capacitances of oxidised and non-oxidised Au surfaces are comparable

Low Capacitive Inductors for Fast Switching Devices in Active Power Factor Correction Applications

DEFF Research Database (Denmark)

Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E.

2014-01-01

This paper examines different winding strategies for reduced capacitance inductors in active power factor correction circuits (PFC). The effect of the parasitic capacitance is analyzed from an electro magnetic compatibility (EMI) and efficiency point of views. The purpose of this work is to inves......This paper examines different winding strategies for reduced capacitance inductors in active power factor correction circuits (PFC). The effect of the parasitic capacitance is analyzed from an electro magnetic compatibility (EMI) and efficiency point of views. The purpose of this work...... is to investigate different winding approaches and identify suitable solutions for high switching frequency/high speed transition PFC designs. A low parasitic capacitance PCB based inductor design is proposed to address the challenges imposed by high switching frequency PFC Boost converters....

Development of a Capacitive Ice Sensor to Measure Ice Growth in Real Time

Directory of Open Access Journals (Sweden)

Xiang Zhi

2015-03-01

Full Text Available This paper presents the development of the capacitive sensor to measure the growth of ice on a fuel pipe surface in real time. The ice sensor consists of pairs of electrodes to detect the change in capacitance and a thermocouple temperature sensor to examine the ice formation situation. In addition, an environmental chamber was specially designed to control the humidity and temperature to simulate the ice formation conditions. From the humidity, a water film is formed on the ice sensor, which results in an increase in capacitance. Ice nucleation occurs, followed by the rapid formation of frost ice that decreases the capacitance suddenly. The capacitance is saturated. The developed ice sensor explains the ice growth providing information about the icing temperature in real time.

Development of a capacitive ice sensor to measure ice growth in real time.

Science.gov (United States)

Zhi, Xiang; Cho, Hyo Chang; Wang, Bo; Ahn, Cheol Hee; Moon, Hyeong Soon; Go, Jeung Sang

2015-03-19

This paper presents the development of the capacitive sensor to measure the growth of ice on a fuel pipe surface in real time. The ice sensor consists of pairs of electrodes to detect the change in capacitance and a thermocouple temperature sensor to examine the ice formation situation. In addition, an environmental chamber was specially designed to control the humidity and temperature to simulate the ice formation conditions. From the humidity, a water film is formed on the ice sensor, which results in an increase in capacitance. Ice nucleation occurs, followed by the rapid formation of frost ice that decreases the capacitance suddenly. The capacitance is saturated. The developed ice sensor explains the ice growth providing information about the icing temperature in real time.

A current-mode voltage regulator with an embedded sub-threshold reference for a passive UHF RFID transponder

Energy Technology Data Exchange (ETDEWEB)

Liu Zhongqi [Department of Electronic Engineering, Tsinghua University, Beijing 100084 (China); Zhang Chun; Li Yongming; Wang Zhihua, E-mail: liu-zq04@mails.tsinghua.edu.c [Institute of Microelectronics, Tsinghua University, Beijing 100084 (China)

2010-06-15

This paper presents a current-mode voltage regulator for a passive UHF RFID transponder. The passive tag power is extracted from RF energy through the RF-to-DC rectifier. Due to huge variations of the incoming RF power, the rectifier output voltage should be regulated to achieve a stable power supply. By accurately controlling the current flowing into the load with an embedded sub-threshold reference, the regulated voltage varies in a range of 1-1.3 V from -20 to 80 {sup 0}C, and a bandwidth of about 100 kHz is achieved for a fast power recovery. The circuit is fabricated in UMC 0.18 {mu}m mixed-mode CMOS technology, and the current consumption is only 1 {mu}A. (semiconductor integrated circuits)

A current-mode voltage regulator with an embedded sub-threshold reference for a passive UHF RFID transponder

International Nuclear Information System (INIS)

Liu Zhongqi; Zhang Chun; Li Yongming; Wang Zhihua

2010-01-01

This paper presents a current-mode voltage regulator for a passive UHF RFID transponder. The passive tag power is extracted from RF energy through the RF-to-DC rectifier. Due to huge variations of the incoming RF power, the rectifier output voltage should be regulated to achieve a stable power supply. By accurately controlling the current flowing into the load with an embedded sub-threshold reference, the regulated voltage varies in a range of 1-1.3 V from -20 to 80 0 C, and a bandwidth of about 100 kHz is achieved for a fast power recovery. The circuit is fabricated in UMC 0.18 μm mixed-mode CMOS technology, and the current consumption is only 1 μA. (semiconductor integrated circuits)

Resonant gravimetric immunosensing based on capacitive micromachined ultrasound transducers

KAUST Repository

Viržonis, Darius

2014-04-08

High-frequency (40 MHz) and low-frequency (7 MHz) capacitive micromachined ultrasound transducers (CMUT) were fabricated and tested for use in gravimetric detection of biomolecules. The low-frequency CMUT sensors have a gold-coated surface, while the high-frequency sensors have a silicon nitride surface. Both surfaces were functionalized with bovine leukemia virus antigen gp51 acting as the antigen. On addition of an a specific antibody labeled with horseradish peroxidase (HRP), the antigen/antibody complex is formed on the surface and quantified by HRP-catalyzed oxidation of tetramethylbenzidine. It has been found that a considerably smaller quantity of immuno complex is formed on the high frequency sensor surface. In parallel, the loading of the surface of the CMUT was determined via resonance frequency and electromechanical resistance readings. Following the formation of the immuno complexes, the resonance frequencies of the low-frequency and high-frequency sensors decrease by up to 420 and 440 kHz, respectively. Finite element analysis reveals that the loading of the (gold-coated) low frequency sensors is several times larger than that on high frequency sensors. The formation of the protein film with pronounced elasticity and stress on the gold surface case is discussed. We also discuss the adoption of this method for the detection of DNA using a hybridization assay following polymerase chain reaction.

A voltage regulator system with dynamic bandwidth boosting for passive UHF RFID transponders

International Nuclear Information System (INIS)

Shen Jinpeng; Wang Xin'an; Liu Shan; Li Shoucheng; Ruan Zhengkun

2013-01-01

This paper presents a voltage regulator system for passive UHF RFID transponders, which contains a rectifier, a limiter, and a regulator. The rectifier achieves power by rectifying the incoming RF energy. Due to the huge variation of the rectified voltage, a limiter at the rectifier output is used to clamp the rectified voltage. In this paper, the design of a limiter circuit is discussed in detail, which can provide a stable limiting voltage with low sensitivity to temperature variation and process dispersion. The key aspect of the voltage regulator system is the dynamic bandwidth boosting in the regulator. By sensing the excess current that is bypassed in the limiter during periods of excess energy, the bias current as well as the bandwidth of the regulator are increased, the output supply voltage can recover quickly from line transients during the periods of no RF energy to a full blast of RF energy. This voltage regulator system is implemented in a 0.18 μm CMOS process. (semiconductor integrated circuits)

A UHF RFID system with on-chip-antenna tag for short range communication

International Nuclear Information System (INIS)

Peng Qi; Zhang Chun; Zhao Xijin; Wang Zhihua

2015-01-01

A UHF RF identification system based on the 0.18 μm CMOS process has been developed for short range and harsh size requirement applications, which is composed of a fully integrated tag and a special reader. The whole tag chip with the antenna takes up an area of 0.36 mm 2 , which is smaller than other reported tags with an on-chip antenna (OCA) using the standard CMOS process. A self-defined protocol is proposed to reduce the power consumption, and minimize the size of the tag. The specialized SOC reader system consists of the RF transceiver, digital baseband, MCU and host interface. Its power consumption is about 500 mW. Measurement results show that the system's reading range is 2 mm with 20 dBm reader output power. With an inductive antenna printed on a paper substrate around the OCA tag, the reading range can be extended from several centimeters to meters, depending on the shape and size of the inductive antenna. (paper)

CMOS capacitive biosensors for highly sensitive biosensing applications.

Science.gov (United States)

Chang, An-Yu; Lu, Michael S-C

2013-01-01

Magnetic microbeads are widely used in biotechnology and biomedical research for manipulation and detection of cells and biomolecules. Most lab-on-chip systems capable of performing manipulation and detection require external instruments to perform one of the functions, leading to increased size and cost. This work aims at developing an integrated platform to perform these two functions by implementing electromagnetic microcoils and capacitive biosensors on a CMOS (complementary metal oxide semiconductor) chip. Compared to most magnetic-type sensors, our detection method requires no externally applied magnetic fields and the associated fabrication is less complicated. In our experiment, microbeads coated with streptavidin were driven to the sensors located in the center of microcoils with functionalized anti-streptavidin antibody. Detection of a single microbead was successfully demonstrated using a capacitance-to-frequency readout. The average capacitance changes for the experimental and control groups were -5.3 fF and -0.2 fF, respectively.

Micromachined capacitive ultrasonic immersion transducer array

Science.gov (United States)

Jin, Xuecheng

Capacitive micromachined ultrasonic transducers (cMUTs) have emerged as an attractive alternative to conventional piezoelectric ultrasonic transducers. They offer performance advantages of wide bandwidth and sensitivity that have heretofore been attainable. In addition, micromachining technology, which has benefited from the fast-growing microelectronics industry, enables cMUT array fabrication and electronics integration. This thesis describes the design and fabrication of micromachined capacitive ultrasonic immersion transducer arrays. The basic transducer electrical equivalent circuit is derived from Mason's theory. The effects of Lamb waves and Stoneley waves on cross coupling and acoustic losses are discussed. Electrical parasitics such as series resistance and shunt capacitance are also included in the model of the transducer. Transducer fabrication technology is systematically studied. Device dimension control in both vertical and horizontal directions, process alternatives and variations in membrane formation, via etch and cavity sealing, and metalization as well as their impact on transducer performance are summarized. Both 64 and 128 element 1-D array transducers are fabricated. Transducers are characterized in terms of electrical input impedance, bandwidth, sensitivity, dynamic range, impulse response and angular response, and their performance is compared with theoretical simulation. Various schemes for cross coupling reduction is analyzed, implemented, and verified with both experiments and theory. Preliminary results of immersion imaging are presented using 64 elements 1-D array transducers for active source imaging.

CMOS capacitive sensors for lab-on-chip applications a multidisciplinary approach

CERN Document Server

Ghafar-Zadeh, Ebrahim

2010-01-01

The main components of CMOS capacitive biosensors including sensing electrodes, bio-functionalized sensing layer, interface circuitries and microfluidic packaging are verbosely explained in chapters 2-6 after a brief introduction on CMOS based LoCs in Chapter 1. CMOS Capacitive Sensors for Lab-on-Chip Applications is written in a simple pedagogical way. It emphasises practical aspects of fully integrated CMOS biosensors rather than mathematical calculations and theoretical details. By using CMOS Capacitive Sensors for Lab-on-Chip Applications, the reader will have circuit design methodologies,

Inside-out electrical capacitance tomography

DEFF Research Database (Denmark)

Kjærsgaard-Rasmussen, Jimmy; Meyer, Knud Erik

2011-01-01

In this work we demonstrate the construction of an ‘inside-out’ sensor geometry for electrical capacitance tomography (ECT). The inside-out geometry has the electrodes placed around a tube, as usual, but measuring ‘outwards’. The flow between the electrodes and an outer tube is reconstructed...

Electrical characterization of MIS devices using PECVD SiN{sub x}:H films for application of silicon solar cells

Energy Technology Data Exchange (ETDEWEB)

Yoo, Jin-Su; Cho, Jun-Sik; Park, Joo-Hyung; Ahn, Seung-Kyu; Shin, Kee-Shik; Yoon, Kyung-Hoon [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Yi, Jun-Sin [Sungkyunkwan University, Suwon (Korea, Republic of)

2012-07-15

The surface passivation of crystalline silicon solar cells using plasma enhanced chemical vapor deposition (PECVD), hydrogenated, silicon-nitride (SiN{sub x}:H) thin films has become significant due to a low-temperature, low-cost and very effective defect passivation process. Also, a good quality antireflection coating can be formed. In this work, SiN{sub x}:H thin films were deposited by varying the gas ratio R (=NH{sub 3}/SiH{sub 4}+NH{sub 3}) and were annealed by rapid thermal processing (RTP). Metal-insulator- semiconductor (MIS) devices were fabricated using SiN{sub x}:H thin films as insulator layers and they were analyzed in the temperature range of 100 - 400 K by using capacitance-voltage (C-V) and current-voltage (I-V) measurements. The annealed SiN{sub x}:H thin films were evaluated by using the electrical properties at different temperature to determine the effect of surface passivation. We achieved an energy conversion efficiency of 18.1% under one-sun standard testing conditions for large-area (156 mm x 156 mm) crystalline-silicon solar cells.

Photoluminescence and electrical properties of silicon oxide and silicon nitride superlattices containing silicon nanocrystals

International Nuclear Information System (INIS)

Shuleiko, D V; Ilin, A S

2016-01-01

Photoluminescence and electrical properties of superlattices with thin (1 to 5 nm) alternating silicon-rich silicon oxide or silicon-rich silicon nitride, and silicon oxide or silicon nitride layers containing silicon nanocrystals prepared by plasma-enhanced chemical vapor deposition with subsequent annealing were investigated. The entirely silicon oxide based superlattices demonstrated photoluminescence peak shift due to quantum confinement effect. Electrical measurements showed the hysteresis effect in the vicinity of zero voltage due to structural features of the superlattices from SiOa 93 /Si 3 N 4 and SiN 0 . 8 /Si 3 N 4 layers. The entirely silicon nitride based samples demonstrated resistive switching effect, comprising an abrupt conductivity change at about 5 to 6 V with current-voltage characteristic hysteresis. The samples also demonstrated efficient photoluminescence with maximum at ∼1.4 eV, due to exiton recombination in silicon nanocrystals. (paper)

Triboelectricity in capacitive biopotential measurements.

Science.gov (United States)

Wartzek, Tobias; Lammersen, Thomas; Eilebrecht, Benjamin; Walter, Marian; Leonhardt, Steffen

2011-05-01

Capacitive biopotential measurements suffer from strong motion artifacts, which may result in long time periods during which a reliable measurement is not possible. This study examines contact electrification and triboelectricity as possible reasons for these artifacts and discusses local triboelectric effects on the electrode-body interface as well as global electrostatic effects as common-mode interferences. It will be shown that most probably the triboelectric effects on the electrode-body interface are the main reason for artifacts, and a reduction of artifacts can only be achieved with a proper design of the electrode-body interface. For a deeper understanding of the observed effects, a mathematical model for triboelectric effects in highly isolated capacitive biopotential measurements is presented and verified with experiments. Based on these analyses of the triboelectric effects on the electrode-body interface, different electrode designs are developed and analyzed in order to minimize artifacts due to triboelectricity on the electrode-body interface. © 2011 IEEE

Nonlinear dynamics of capacitive charging and desalination by porous electrodes

Science.gov (United States)

Biesheuvel, P. M.; Bazant, M. Z.

2010-03-01

The rapid and efficient exchange of ions between porous electrodes and aqueous solutions is important in many applications, such as electrical energy storage by supercapacitors, water desalination and purification by capacitive deionization, and capacitive extraction of renewable energy from a salinity difference. Here, we present a unified mean-field theory for capacitive charging and desalination by ideally polarizable porous electrodes (without Faradaic reactions or specific adsorption of ions) valid in the limit of thin double layers (compared to typical pore dimensions). We illustrate the theory for the case of a dilute, symmetric, binary electrolyte using the Gouy-Chapman-Stern (GCS) model of the double layer, for which simple formulae are available for salt adsorption and capacitive charging of the diffuse part of the double layer. We solve the full GCS mean-field theory numerically for realistic parameters in capacitive deionization, and we derive reduced models for two limiting regimes with different time scales: (i) in the “supercapacitor regime” of small voltages and/or early times, the porous electrode acts like a transmission line, governed by a linear diffusion equation for the electrostatic potential, scaled to the RC time of a single pore, and (ii) in the “desalination regime” of large voltages and long times, the porous electrode slowly absorbs counterions, governed by coupled, nonlinear diffusion equations for the pore-averaged potential and salt concentration.

Quality assessment of MOZAIC and IAGOS capacitive hygrometers: insights from airborne field studies

Directory of Open Access Journals (Sweden)

Patrick Neis

2015-10-01

Full Text Available In 2011, the MOZAIC (Measurement of Ozone by AIRBUS In-Service Aircraft successor programme IAGOS (In-service Aircraft for a Global Observing System started to equip their long-haul passenger aircraft with the modified capacitive hygrometer Vaisala HUMICAP® of type H. The assurance of the data quality and the consistency of the data set during the transition from MOZAIC Capacitive Hygrometers to IAGOS Capacitive Hygrometers were evaluated within the CIRRUS-III and AIRTOSS-ICE field studies. During these performance tests, the capacitive hygrometers were operated aboard a Learjet 35A aircraft together with a closed-cell Lyman-α fluorescence hygrometer, an open-path tunable diode laser (TDL system and a closed-cell, direct TDL absorption hygrometer for water vapour measurement. For MOZAIC-typical operation conditions, the comparison of relative humidity (RH data from the capacitive hygrometers and reference instruments yielded remarkably good agreement with an uncertainty of 5% RH. The temperature dependence of the sensor's response time was derived from the cross-correlation of capacitive hygrometer data and smoothed data from the fast-responding reference instruments. The resulting exponential moving average function could explain the major part of the observed deviations between the capacitive hygrometers and the reference instruments.

Intermittent-contact scanning capacitance microscopy imaging and modeling for overlay metrology

International Nuclear Information System (INIS)

Mayo, S.; Kopanski, J. J.; Guthrie, W. F.

1998-01-01

Overlay measurements of the relative alignment between sequential layers are one of the most critical issues for integrated circuit (IC) lithography. We have implemented on an AFM platform a new intermittent-contact scanning capacitance microscopy (IC-SCM) mode that is sensitive to the tip proximity to an IC interconnect, thus making it possible to image conductive structures buried under planarized dielectric layers. Such measurements can be used to measure IC metal-to-resist lithography overlay. The AFM conductive cantilever probe oscillating in a vertical plane was driven at frequency ω, below resonance. By measuring the tip-to-sample capacitance, the SCM signal is obtained as the difference in capacitance, ΔC(ω), at the amplitude extremes. Imaging of metallization structures was obtained with a bars-in-bars aluminum structure embedded in a planarized dielectric layer 1 μm thick. We have also modeled, with a two-dimensional (2D) electrostatic field simulator, IC-SCM overlay data of a metallization structure buried under a planarized dielectric having a patterned photoresist layer deposited on it. This structure, which simulates the metal-to-resist overlay between sequential IC levels, allows characterization of the technique sensitivity. The capacitance profile across identical size electrically isolated or grounded metal lines embedded in a dielectric was shown to be different. The floating line shows capacitance enhancement at the line edges, with a minimum at the line center. The grounded line shows a single capacitance maximum located at the line center, with no edge enhancement. For identical line dimensions, the capacitance is significantly larger for grounded lines making them easier to image. A nonlinear regression algorithm was developed to extract line center and overlay parameters with approximately 3 nm resolution at the 95% confidence level, showing the potential of this technique for sub-micrometer critical dimension metrology. Symmetric test

Design and tests of the silicon sensors for the ZEUS micro vertex detector

International Nuclear Information System (INIS)

Dannheim, D.; Koetz, U.; Coldewey, C.; Fretwurst, E.; Garfagnini, A.; Klanner, R.; Martens, J.; Koffeman, E.; Tiecke, H.; Carlin, R.

2003-01-01

To fully exploit the HERA-II upgrade, the ZEUS experiment has installed a Micro Vertex Detector (MVD) using n-type, single-sided, silicon μ-strip sensors with capacitive charge division. The sensors have a readout pitch of 120 μm, with five intermediate strips (20 μm strip pitch). The designs of the silicon sensors and of the test structures used to verify the technological parameters, are presented. Results on the electrical measurements are discussed. A total of 1123 sensors with three different geometries have been produced by Hamamatsu Photonics K.K. Irradiation tests with reactor neutrons and 60 Co photons have been performed for a small sample of sensors. The results on neutron irradiation (with a fluence of 1x10 13 1 MeV equivalent neutrons/cm 2 ) are well described by empirical formulae for bulk damage. The 60 Co photons (with doses up to 2.9 kGy) show the presence of generation currents in the SiO 2 -Si interface, a large shift of the flatband voltage and a decrease of the hole mobility

Integrated microelectronic capacitive readout subsystem for lab-on-a-chip applications

International Nuclear Information System (INIS)

Spathis, Christos; Georgakopoulou, Konstantina; Petrellis, Nikos; Efstathiou, Konstantinos; Birbas, Alexios

2014-01-01

A mixed-signal capacitive biosensor readout system is presented with its main readout functionality embedded in an integrated circuit, compatible with complementary metal oxide semiconductor-type biosensors. The system modularity allows its usage as a consumable since it eventually leads to a system-on-chip where sensor and readout circuitry are hosted on the same die. In this work, a constant current source is used for measuring the input capacitance. Compared to most capacitive biosensor readout circuits, this method offers the convenience of adjusting both the range and the resolution, depending on the requirements dictated by the application. The chip consumes less than 5 mW of power and the die area is 0.06 mm 2 . It shows a broad input capacitance range (capable of measuring bio-capacitances from 6 pF to 9.8 nF), configurable resolution (down to 1 fF), robustness to various biological experiments and good linearity. The integrated nature of the readout system is proven to be sufficient both for one-time in situ (consumable-type) bio-measurements and its incorporation into a point-of-care system. (paper)

Fully integrated low-noise readout circuit with automatic offset cancellation loop for capacitive microsensors.

Science.gov (United States)

Song, Haryong; Park, Yunjong; Kim, Hyungseup; Cho, Dong-Il Dan; Ko, Hyoungho

2015-10-14

Capacitive sensing schemes are widely used for various microsensors; however, such microsensors suffer from severe parasitic capacitance problems. This paper presents a fully integrated low-noise readout circuit with automatic offset cancellation loop (AOCL) for capacitive microsensors. The output offsets of the capacitive sensing chain due to the parasitic capacitances and process variations are automatically removed using AOCL. The AOCL generates electrically equivalent offset capacitance and enables charge-domain fine calibration using a 10-bit R-2R digital-to-analog converter, charge-transfer switches, and a charge-storing capacitor. The AOCL cancels the unwanted offset by binary-search algorithm based on 10-bit successive approximation register (SAR) logic. The chip is implemented using 0.18 μm complementary metal-oxide-semiconductor (CMOS) process with an active area of 1.76 mm². The power consumption is 220 μW with 3.3 V supply. The input parasitic capacitances within the range of -250 fF to 250 fF can be cancelled out automatically, and the required calibration time is lower than 10 ms.

Fully Integrated Low-Noise Readout Circuit with Automatic Offset Cancellation Loop for Capacitive Microsensors

Directory of Open Access Journals (Sweden)

Haryong Song

2015-10-01

Full Text Available Capacitive sensing schemes are widely used for various microsensors; however, such microsensors suffer from severe parasitic capacitance problems. This paper presents a fully integrated low-noise readout circuit with automatic offset cancellation loop (AOCL for capacitive microsensors. The output offsets of the capacitive sensing chain due to the parasitic capacitances and process variations are automatically removed using AOCL. The AOCL generates electrically equivalent offset capacitance and enables charge-domain fine calibration using a 10-bit R-2R digital-to-analog converter, charge-transfer switches, and a charge-storing capacitor. The AOCL cancels the unwanted offset by binary-search algorithm based on 10-bit successive approximation register (SAR logic. The chip is implemented using 0.18 μm complementary metal-oxide-semiconductor (CMOS process with an active area of 1.76 mm2. The power consumption is 220 μW with 3.3 V supply. The input parasitic capacitances within the range of −250 fF to 250 fF can be cancelled out automatically, and the required calibration time is lower than 10 ms.

Large Capacitance Measurement by Multiple Uses of MBL Charge Sensor

Science.gov (United States)

Lee, Jung Sook; Chae, Min; Kim, Jung Bog

2010-01-01

A recent article by Morse described interesting electrostatics experiments using an MBL charge sensor. In this application, the charge sensor has a large capacitance compared to the charged test object, so nearly all charges can be transferred to the sensor capacitor from the capacitor to be measured. However, the typical capacitance of commercial…

Experimental Study on Strain Reliability of Embroidered Passive UHF RFID Textile Tag Antennas and Interconnections

Directory of Open Access Journals (Sweden)

Xiaochen Chen

2017-01-01

Full Text Available We present embroidered antennas and interconnections in passive UHF RFID textile tags and test their strain reliability. Firstly, we fabricate tag antennas on two different stretchable fabric substrates by five different embroidery patterns and choose the most stretchable ones for testing. Next, the tag ICs are attached by sewing and gluing, and the tag reliability during repeated stretching cycles is evaluated through wireless measurements. Initially, the chosen tags achieve read ranges of 6–8 meters and can strain up to 140–150% of their original length. After 100 stretching cycles to 80% of their maximum strain, the read ranges of the tags with glued interconnections are similar to the initial values. In addition, also the read ranges of the tags with sewed interconnections are still more than 70%–85% of their initial values. However, some challenges with the reproducibility need to be solved next.

Capacitors and Resistance-Capacitance Networks.

Science.gov (United States)

Balabanian, Norman; Root, Augustin A.

This programed textbook was developed under a contract with the United States Office of Education as Number 5 in a series of materials for use in an electrical engineering sequence. It is divided into three parts--(1) capacitors, (2) voltage-current relationships, and (3) simple resistance-capacitance networks. (DH)

A new normalization method based on electrical field lines for electrical capacitance tomography

International Nuclear Information System (INIS)

Zhang, L F; Wang, H X

2009-01-01

Electrical capacitance tomography (ECT) is considered to be one of the most promising process tomography techniques. The image reconstruction for ECT is an inverse problem to find the spatially distributed permittivities in a pipe. Usually, the capacitance measurements obtained from the ECT system are normalized at the high and low permittivity for image reconstruction. The parallel normalization model is commonly used during the normalization process, which assumes the distribution of materials in parallel. Thus, the normalized capacitance is a linear function of measured capacitance. A recently used model is a series normalization model which results in the normalized capacitance as a nonlinear function of measured capacitance. The newest presented model is based on electrical field centre lines (EFCL), and is a mixture of two normalization models. The multi-threshold method of this model is presented in this paper. The sensitivity matrices based on different normalization models were obtained, and image reconstruction was carried out accordingly. Simulation results indicate that reconstructed images with higher quality can be obtained based on the presented model

Large area, low capacitance Si(Li) detectors for high rate x-ray applications

International Nuclear Information System (INIS)

Rossington, C.S.; Fine, P.M.; Madden, N.W.

1992-10-01

Large area, single-element Si(Li) detectors have been fabricated using a novel geometry which yields detectors with reduced capacitance and hence reduced noise at short amplifier pulse-processing times. A typical device employing the new geometry with a thickness of 6 mm and an active area of 175 mm 2 has a capacitance of only 0.5 pf, compared to 2.9 pf for a conventional planar device with equivalent dimensions. These new low capacitance detectors, used in conjunction with low capacitance field effect transistors, will result in x-ray spectrometers capable of operating at very high count rates while still maintaining excellent energy resolution. The spectral response of the low capacitance detectors to a wide range of x-ray energies at 80 K is comparable to typical state-of-the-art conventional Si(Li) devices. In addition to their low capacitance, the new devices offer other advantages over conventional detectors. Detector fabrication procedures, I-V and C-V characteristics, noise performance, and spectral response to 2-60 keV x-rays are described

Radiation defect distribution in silicon irradiated with 600 keV electrons

International Nuclear Information System (INIS)

Hazdra, P.; Dorschner, H.

2003-01-01

Low-doped n-type float zone silicon was irradiated with 600 keV electrons to fluences from 2x10 13 to 1x10 15 cm -2 . Radiation defects, their introduction rates and full-depth profiles were measured by two complementary methods - the capacitance deep level spectroscopy and the high-voltage current transient spectroscopy. Results show that, in the vicinity of the anode junction, the profile of vacancy-related defect centers is strongly influenced by electric field and an excessive generation of vacancies. In the bulk, the slope of the profile can be derived from the distribution of absorbed dose taking into the account the threshold energy necessary for Frenkel pair formation and the dependency of the defect introduction rate on electron energy

Capacitance enhancement via electrode patterning

International Nuclear Information System (INIS)

Ho, Tuan A.; Striolo, Alberto

2013-01-01

The necessity of increasing the energy density in electric double layer capacitors to meet current demand is fueling fundamental and applied research alike. We report here molecular dynamics simulation results for aqueous electrolytes near model electrodes. Particular focus is on the effect of electrode patterning on the structure of interfacial electrolytes, and on the potential drop between the solid electrodes and the bulk electrolytes. The latter is estimated by numerically integrating the Poisson equation using the charge densities due to water and ions accumulated near the interface as input. We considered uniform and patterned electrodes, both positively and negatively charged. The uniformly charged electrodes are modeled as graphite. The patterned ones are obtained by removing carbon atoms from the top-most graphene layer, yielding nanoscopic squares and stripes patterns. For simplicity, the patterned electrodes are effectively simulated as insulators (the charge remains localized on the top-most layer of carbon atoms). Our simulations show that the patterns alter the structure of water and the accumulation of ions at the liquid-solid interfaces. Using aqueous NaCl solutions, we found that while the capacitance calculated for three positively charged electrodes did not change much, that calculated for the negatively charged electrodes significantly increased upon patterning. We find that both water structure and orientation, as well as ion accumulation affect the capacitance. As electrode patterning affects differently water structure and ion accumulation, it might be possible to observe ion-specific effects. These results could be useful for advancing our understanding of electric double layer capacitors, capacitive desalination processes, as well as of fundamental interfacial electrolytes properties

Fabrication and evaluation of series-triple quantum dots by thermal oxidation of silicon nanowire

International Nuclear Information System (INIS)

Uchida, Takafumi; Jo, Mingyu; Tsurumaki-Fukuchi, Atsushi; Arita, Masashi; Takahashi, Yasuo; Fujiwara, Akira

2015-01-01

Series-connected triple quantum dots were fabricated by a simple two-step oxidation technique using the pattern-dependent oxidation of a silicon nanowire and an additional oxidation of the nanowire through the gap of the fine gates attached to the nanowire. The characteristics of multi-dot single-electron devices are obtained. The formation of each quantum dot beneath an attached gate is confirmed by analyzing the electrical characteristics and by evaluating the gate capacitances between all pairings of gates and quantum dots. Because the gate electrode is automatically attached to each dot, the device structure benefits from scalability. This technique promises integrability of multiple quantum dots with individual control gates

Capacitive Cells for Dielectric Constant Measurement

Science.gov (United States)

Aguilar, Horacio Munguía; Maldonado, Rigoberto Franco

2015-01-01

A simple capacitive cell for dielectric constant measurement in liquids is presented. As an illustrative application, the cell is used for measuring the degradation of overheated edible oil through the evaluation of their dielectric constant.

Capacitive sensing of droplets for microfluidic devices based on thermocapillary actuation

NARCIS (Netherlands)

Chen, J.-Z.; Darhuber, A.A.; Troian, S.M.; Wagner, S.

2004-01-01

The design and performance of a miniaturized coplanar capacitive sensor is presented whose electrode arrays can also function as resistive microheaters for thermocapillary actuation of liquid films and droplets. Optimal compromise between large capacitive signal and high spatial resolution is

An analog front-end bipolar-transistor integrated circuit for the SDC silicon tracker

International Nuclear Information System (INIS)

Kipnis, I.; Spieler, H.; Collins, T.

1994-01-01

Since 1989 the Solenoidal Detector Collaboration (SDC) has been developing a general purpose detector to be operated at the Superconducting Super Collider (SSC). A low-noise, low-power, high-bandwidth, radiation hard, silicon bipolar-transistor full-custom integrated circuit (IC) containing 64 channels of analog signal processing has been developed for the SDS silicon tracker. The IC was designed and tested at LBL and was fabricated using AT and T's CBIC-U2, 4 GHz f T complementary bipolar technology. Each channel contains the following functions: low-noise preamplification, pulse shaping and threshold discrimination. This is the first iteration of the production analog IC for the SDC silicon tracker. The IC is laid out to directly match the 50 μm pitch double-sided silicon strip detector. The chip measures 6.8 mm x 3.1 mm and contains 3,600 transistors. Three stages of amplification provide 180 mV/fC of gain with a 35 nsec peaking time at the comparator input. For a 14 pF detector capacitance, the equivalent noise charge is 1300 el. rms at a power consumption of 1 mW/channel from a single 3.5 V supply. With the discriminator threshold set to 4 times the noise level, a 16nsec time-walk for 1.25 to 10 fC signals is achieved using a time-walk compensation network. Irradiation tests at TRIUMF to a φ = 10 14 protons/cm 2 have been performed on the JC, demonstrating the radiation hardness of the complementary bipolar process

A Flexible Capacitive Sensor with Encapsulated Liquids as Dielectrics

Directory of Open Access Journals (Sweden)

Yasunari Hotta

2012-03-01

Full Text Available Flexible and high-sensitive capacitive sensors are demanded to detect pressure distribution and/or tactile information on a curved surface, hence, wide varieties of polymer-based flexible MEMS sensors have been developed. High-sensitivity may be achieved by increasing the capacitance of the sensor using solid dielectric material while it deteriorates the flexibility. Using air as the dielectric, to maintain the flexibility, sacrifices the sensor sensitivity. In this paper, we demonstrate flexible and highly sensitive capacitive sensor arrays that encapsulate highly dielectric liquids as the dielectric. Deionized water and glycerin, which have relative dielectric constants of approximately 80 and 47, respectively, could increase the capacitance of the sensor when used as the dielectric while maintaining flexibility of the sensor with electrodes patterned on flexible polymer substrates. A reservoir of liquids between the electrodes was designed to have a leak path, which allows the sensor to deform despite of the incompressibility of the encapsulated liquids. The proposed sensor was microfabricated and demonstrated successfully to have a five times greater sensitivity than sensors that use air as the dielectric.

Probing 2D black phosphorus by quantum capacitance measurements

International Nuclear Information System (INIS)

Kuiri, Manabendra; Kumar, Chandan; Chakraborty, Biswanath; Gupta, Satyendra N; Naik, Mit H; Jain, Manish; Sood, A K; Das, Anindya

2015-01-01

Two-dimensional materials and their heterostructures have emerged as a new class of materials, not only for fundamental physics but also for electronic and optoelectronic applications. Black phosphorus (BP) is a relatively new addition to this class of materials. Its strong in-plane anisotropy makes BP a unique material for making conceptually new types of electronic devices. However, the global density of states (DOS) of BP in device geometry has not been measured experimentally. Here, we report the quantum capacitance measurements together with the conductance measurements on an hBN-protected few-layer BP (∼six layers) in a dual-gated field effect transistor (FET) geometry. The measured DOS from our quantum capacitance is compared with density functional theory (DFT). Our results reveal that the transport gap for quantum capacitance is smaller than that in conductance measurements due to the presence of localized states near the band edge. The presence of localized states is confirmed by the variable range hopping seen in our temperature dependence conductivity. A large asymmetry is observed between the electron and hole side. This asymmetric nature is attributed to the anisotropic band dispersion of BP. Our measurements establish the uniqueness of quantum capacitance in probing the localized states near the band edge, hitherto not seen in conductance measurements. (paper)

A Micro Dynamically Tuned Gyroscope with Adjustable Static Capacitance

Directory of Open Access Journals (Sweden)

Lun Kong

2013-02-01

Full Text Available This paper presents a novel micro dynamically tuned gyroscope (MDTG with adjustable static capacitance. First, the principle of MDTG is theoretically analyzed. Next, some simulations under the optimized structure parameters are given as a reference for the mask design of the rotor wafer and electrode plates. As two key components, the process flows of the rotor wafer and electrode plates are described in detail. All the scanning electron microscopy (SEM photos show that the fabrication process is effective and optimized. Then, an assembly model is designed for the static capacitance adjustable MDTG, whose static capacitance can be changed by rotating the lower electrode plate support and substituting gasket rings of different thicknesses. Thus, the scale factor is easily changeable. Afterwards, the digitalized closed-loop measurement circuit is simulated. The discrete correction and decoupling modules are designed to make the closed-loop stable and cross-coupling effect small. The dual axis closed-loop system bandwidths can reach more than 60 Hz and the dual axis scale factors are completely symmetrical. All the simulation results demonstrate the proposed fabrication of the MDTG can meet the application requirements. Finally, the paper presents the test results of static and dynamic capacitance values which are consistent with the simulation values.

Fabrication of a printed capacitive air-gap touch sensor

Science.gov (United States)

Lee, Sang Hoon; Seo, Hwiwon; Lee, Sangyoon

2018-05-01

Unlike lithography-based processes, printed electronics does not require etching, which makes it difficult to fabricate electronic devices with an air gap. In this study, we propose a method to fabricate capacitive air-gap touch sensors via printing and coating. First, the bottom electrode was fabricated on a flexible poly(ethylene terephthalate) (PET) substrate using roll-to-roll gravure printing with silver ink. Then poly(dimethylsiloxane) (PDMS) was spin coated to form a sacrificial layer. The top electrode was fabricated on the sacrificial layer by spin coating with a stretchable silver ink. The sensor samples were then put in a tetrabutylammonium (TBAF) bath to generate the air gap by removing the sacrificial layer. The capacitance of the samples was measured for verification, and the results show that the capacitance increases in proportion to the applied force from 0 to 2.5 N.

A microcontroller-based interface circuit for lossy capacitive sensors

International Nuclear Information System (INIS)

Reverter, Ferran; Casas, Òscar

2010-01-01

This paper introduces and analyses a low-cost microcontroller-based interface circuit for lossy capacitive sensors, i.e. sensors whose parasitic conductance (G x ) is not negligible. Such a circuit relies on a previous circuit also proposed by the authors, in which the sensor is directly connected to a microcontroller without using either a signal conditioner or an analogue-to-digital converter in the signal path. The novel circuit uses the same hardware, but it performs an additional measurement and executes a new calibration technique. As a result, the sensitivity of the circuit to G x decreases significantly (a factor higher than ten), but not completely due to the input capacitances of the port pins of the microcontroller. Experimental results show a relative error in the capacitance measurement below 1% for G x x ) shows the effectiveness of the circuit

Studies of the Silicon Tracker resolution using data

CERN Document Server

van Tilburg, J

2010-01-01

Several parameters that influence the hit resolution of the Silicon Tracker have been determined from data. These include charge sharing, cross talk and Lorentz deflection. A charge sharing width of ~4 $\\mu$m has been measured. No charge loss has been observed in the interstrip region. The cross talk to the neighbouring strips is found to vary between 4 − 14%, depending on the total capacitance (sensors plus cable), on whether it is the left or right neighbour and on the Beetle channel number (odd or even). The Lorentz deflection was also investigated and was observed to be small. Finally, the new parameters have been inserted in the LHCb Monte Carlo simulation to update the $\\eta$-correction functions required for the reconstruction of tracks. Compared to the previous tuning the hit resolution in the simulation has increased from ~35 $\\mu$m to ~50 $\\mu$m.

Studies of deep levels in He+-irradiated silicon

International Nuclear Information System (INIS)

Schmidt, D.C.; Barbot, J.F.; Blanchard, C.

1997-01-01

Deep levels created in n-epitaxial silicon by alpha particle irradiation in the dose range from 10 9 to 10 13 particles/cm 2 have been investigated by the deep level transient spectroscopy technique and capacitance-voltage profiling. Under low fluence irradiation at least four main electron traps have been observed. With further increase in irradiation fluence, two new levels located at E c -0.56 eV and E c -0.64 eV appear on the high-temperature side of the DLTS signal. The slope change observed in the amplitude variations of the singly negative charge state of the divacancy versus the dose takes place when these two new levels appear. This suggests that both are multivacancy-related defects. After annealing at 350 C for 15 min, all electron traps have disappeared. Moreover, no shallow levels are created during the annealing. (orig.)

Conjugate Image Theory Applied on Capacitive Wireless Power Transfer

OpenAIRE

Ben Minnaert; Nobby Stevens

2017-01-01

Wireless power transfer using a magnetic field through inductive coupling is steadily entering the market in a broad range of applications. However, for certain applications, capacitive wireless power transfer using electric coupling might be preferable. In order to obtain a maximum power transfer efficiency, an optimal compensation network must be designed at the input and output ports of the capacitive wireless link. In this work, the conjugate image theory is applied to determine this opti...

Structural, electronic properties, and quantum capacitance of B, N and P-doped armchair carbon nanotubes

Energy Technology Data Exchange (ETDEWEB)

Mousavi-Khoshdel, S. Morteza, E-mail: mmousavi@iust.ac.ir [Department of Chemistry, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Jahanbakhsh-bonab, Parisa [Department of Chemistry, Iran University of Science and Technology, Tehran (Iran, Islamic Republic of); Targholi, Ehsan [Young Researchers and Elite Club, Abhar Branch, Islamic Azad University, Abhar (Iran, Islamic Republic of)

2016-10-07

Using DFT calculations, we study the structural parameters, electronic properties and quantum capacitance of N, B, and P-doped armchair carbon nanotubes (CNTs). Fermi level shifts towards conduction band and valence band in N- and B-doped CNTs, respectively. While in the case of P atom, despite having an extra valence electron than carbon, there is no shift in Fermi level. The results revealed from a symmetric capacitance enhancement in P-doped CNT and an asymmetric capacitance enhancement in B and N-doped CNTs. The greatest amount of quantum capacitance of N-doped (6, 6) CNT could be achieved at the concentration range of 0.1–0.15. - Highlights: • Exploration of variation in quantum capacitance of CNTs through doping N, B and P atoms. • Quantum capacitance of CNTs is sensitive to impurities entered in carbon nanotubes. • Maximum quantum capacitance of N-doped CNTs is achieved at the concentration range of 0.1–0.15.

An Enhanced Sensing Application Based on a Flexible Projected Capacitive-Sensing Mattress

Directory of Open Access Journals (Sweden)

Wen-Ying Chang

2014-04-01

Full Text Available This paper presents a cost-effective sensor system for mattresses that can classify the sleeping posture of an individual and prevent pressure ulcers. This system applies projected capacitive sensing to the field of health care. The charge time (CT method was used to sensitively and accurately measure the capacitance of the projected electrodes. The required characteristics of the projected capacitor were identified to develop large-area applications for sensory mattresses. The area of the electrodes, the use of shielding, and the increased length of the transmission line were calibrated to more accurately measure the capacitance of the electrodes in large-size applications. To offer the users comfort in the prone position, a flexible substrate was selected and covered with 16 × 20 electrodes. Compared with the static charge sensitive bed (SCSB, our proposed system-flexible projected capacitive-sensing mattress (FPCSM comes with more electrodes to increase the resolution of posture identification. As for the body pressure system (BPS, the FPCSM has advantages such as lower cost, higher aging-resistance capability, and the ability to sense the capacitance of the covered regions without physical contact. The proposed guard ring design effectively absorbs the noise and interrupts leakage paths. The projected capacitive electrode is suitable for proximity-sensing applications and succeeds at quickly recognizing the sleeping pattern of the user.

Capacitive Sensors for Feedback Control of Microfluidic Devices

Science.gov (United States)

Chen, J. Z.; Darhuber, A. A.; Troian, S. M.; Wagner, S.

2003-11-01

Automation of microfluidic devices based on thermocapillary flow [1] requires feedback control and detection techniques for monitoring the location, and ideally also composition and volume of liquid droplets. For this purpose we have developed a co-planar capacitance technique with a sensitivity of 0.07 pF at a frequency of 370 kHz. The variation in capacitance due to the presence of a droplet is monitored by the output frequency of an RC relaxation oscillator consisting of two inverters, one resistor and one capacitor. We discuss the performance of this coplanar sensor as a function of the electrode dimensions and geometry. These geometric variables determine the electric field penetration depth within the liquid, which in our studies ranged from 30 to 450 microns. Numerical solutions for the capacitance corresponding to the exact fabricated geometry agree very well with experimental data. An approximate analytic solution, which ignores fringe field effects, provides a simple but excellent guide for design development. [1] A. A. Darhuber et al., Appl. Phys. Lett. 82, 657 (2003).

A branch-and-cut-and-price algorithm for the mixed capacitated general routing problem

DEFF Research Database (Denmark)

Bach, Lukas; Wøhlk, Sanne; Lysgaard, Jens

2016-01-01

In this paper, we consider the Mixed Capacitated General Routing Problem which is a combination of the Capacitated Vehicle Routing Problem and the Capacitated Arc Routing Problem. The problem is also known as the Node, Edge, and Arc Routing Problem. We propose a Branch-and-Cut-and-Price algorithm...

Capacitive properties of polypyrrole/activated carbon composite

Directory of Open Access Journals (Sweden)

Porjazoska-Kujundziski Aleksandra

2014-01-01

Full Text Available Electrochemical synthesis of polypyrrole (PPy and polypyrrole / activated carbon (PPy / AC - composite films, with a thickness between 0.5 and 15 μm were performed in a three electrode cell containing 0.1 mol dm-3 Py, 0.5 mol dm-3 NaClO4 dissolved in ACN, and dispersed particles of AC (30 g dm-3. Electrochemical characterization of PPy and PPy / AC composites was performed using cyclic voltammetry (CV and electrochemical impedance spectroscopy (EIS techniques. The linear dependences of the capacitance (qC, redox capacitance (qred, and limiting capacitance (CL of PPy and PPy / AC - composite films on their thickness (L, obtained by electrochemical and impedance analysis, indicate a nearly homogeneous distribution of the incorporated AC particles in the composite films (correlation coefficient between 0.991 and 0.998. The significant enhancement of qC, qred, and CL, was observed for composite films (for ∼40 ± 5% in respect to that of the “pure” PPy. The decreased values of a volume resistivity in the reduced state of the composite film, ρ = 1.3 ⋅ 106 Ω cm (for L = 7.5 μm, for two orders of magnitude, compared to that of PPy - film with the same thickness, ρ ∼ 108 Ω cm, was also noticed.

A readout system for position sensitive measurements of X-ray using silicon strip detectors

CERN Document Server

Dabrowski, W; Grybos, P; Idzik, M; Kudlaty, J

2000-01-01

In this paper we describe the development of a readout system for X-ray measurements using silicon strip detectors. The limitation concerning the inherent spatial resolution of silicon strip detectors has been evaluated by Monte Carlo simulation and the results are discussed. The developed readout system is based on the binary readout architecture and consists of two ASICs: RX32 front-end chip comprising 32 channels of preamplifiers, shapers and discriminators, and COUNT32 counter chip comprising 32 20-bit asynchronous counters and the readout logic. This work focuses on the design and performance of the front-end chip. The RX32 chip has been optimised for a low detector capacitance, in the range of 1-3 pF, and high counting rate applications. It can be used with DC coupled detectors allowing the leakage current up to a few nA per strip. For the prototype chip manufactured in a CMOS process all basic parameters have been evaluated by electronic measurements. The noise below 140 el rms has been achieved for a ...

Effect of deep dislocation levels in silicon on the properties of p-n junctions

Energy Technology Data Exchange (ETDEWEB)

Zakharov, A.G.; Dudko, V.G.; Nabokov, G.M.; Sechenov, D.A.

1988-07-01

We present the results of studies on the influence of deep levels, due to dislocations in electronic-grade silicon, on the lifetime of minority carriers and on the current-voltage and capacitance-voltage characteristics of p-n junctions. The parameters of the deep levels were determined by means of dynamic spectroscopy. The carrier lifetime in the high-resistance region of the p-n junction correlates well with the dislocation density and varies from 10/sup /minus/7/ sec to 3 /centered dot/10/sup /minus/6/ sec when the dislocation density N/sub d/ varies from 10/sup 7/ cm/sup /minus/2/ to 5 /centered dot/10/sup 3/ cm/sup /minus/2/. The voltage across the p-n junction at a high level of injection varies 1.6 to 6.2 v as a function of N/sub d/. The ionization energy of deep levels associated with dislocation in silicon is 0.44 and 0.57 eV, measured from the bottom of the conduction band.

Flexible PVDF ferroelectric capacitive temperature sensor

KAUST Repository

Khan, Naveed; Omran, Hesham; Yao, Yingbang; Salama, Khaled N.

2015-01-01

sensitivity of 16pF/°C. The linearity measurement of the capacitance-temperature relation shows less than 0.7°C error from a best fit straight line. An LC oscillator based temperature sensor is demonstrated based on this capacitor.

Irradiation and annealing of p-type silicon carbide

Energy Technology Data Exchange (ETDEWEB)

Lebedev, Alexander A.; Bogdanova, Elena V.; Grigor' eva, Maria V.; Lebedev, Sergey P. [A.F. Ioffe Physical-Technical Institute, St. Petersburg, 194021 (Russian Federation); Kozlovski, Vitaly V. [St. Petersburg State Polytechnic University, St. Petersburg, 195251 (Russian Federation)

2014-02-21

The development of the technology of semiconductor devices based on silicon carbide and the beginning of their industrial manufacture have made increasingly topical studies of the radiation hardness of this material on the one hand and of the proton irradiation to form high-receptivity regions on the other hand. This paper reports on a study of the carrier removal rate (V{sub d}) in p-6H-SiC under irradiation with 8 MeV protons and of the conductivity restoration in radiation- compensated epitaxial layers of various p-type silicon carbide polytypes. V{sub d} was determined by analysis of capacitance-voltage characteristics and from results of Hall effect measurements. It was found that the complete compensation of samples with the initial value of Na - Nd ≈ 1.5 × 10{sup 18} cm{sup −3} occurs at an irradiation dose of ∼1.1 × 10{sup 16} cm{sup −2}. It is shown that specific features of the sublimation layer SiC (compared to CVD layers) are clearly manifested upon the gamma and electron irradiation and are hardly noticeable under the proton and neutron irradiation. It was also found that the radiation-induced compensation of SiC is retained after its annealing at ≤1000°C. The conductivity is almost completely restored at T ≥ 1200°C. This character of annealing of the radiation compensation is independent of a silicon carbide polytype and the starting doping level of the epitaxial layer. The complete annealing temperatures considerably exceed the working temperatures of SiC-based devices. It is shown that the radiation compensation is a promising method in the technology of high-temperature devices based on SiC.

Wearable Passive E-Textile UHF RFID Tag Based on a Slotted Patch Antenna with Sewn Ground and Microchip Interconnections

Directory of Open Access Journals (Sweden)

Johanna Virkki

2017-01-01

Full Text Available We present a wearable passive UHF RFID tag based on a slotted patch antenna comprising only textile materials (e-textile, textile substrate, and conductive yearn. As a novel manufacturing approach, we realize the patch-to-ground and antenna-to-IC interfaces using only conductive thread and a sewing machine. We outline the electromagnetic optimization of the antenna for body-worn operation through simulations and present a performance comparison between the e-textile tag and a tag produced using regular electronics materials and methods. The measured results show that the textile tag achieves the electrical performance required in practical applications and that the slotted patch type antenna provides stable electromagnetic performance in different body-worn configurations.

Capacitive Feedthroughs for Medical Implants.

Science.gov (United States)

Grob, Sven; Tass, Peter A; Hauptmann, Christian

2016-01-01

Important technological advances in the last decades paved the road to a great success story for electrically stimulating medical implants, including cochlear implants or implants for deep brain stimulation. However, there are still many challenges in reducing side effects and improving functionality and comfort for the patient. Two of the main challenges are the wish for smaller implants on one hand, and the demand for more stimulation channels on the other hand. But these two aims lead to a conflict of interests. This paper presents a novel design for an electrical feedthrough, the so called capacitive feedthrough, which allows both reducing the size, and increasing the number of included channels. Capacitive feedthroughs combine the functionality of a coupling capacitor and an electrical feedthrough within one and the same structure. The paper also discusses the progress and the challenges of the first produced demonstrators. The concept bears a high potential in improving current feedthrough technology, and could be applied on all kinds of electrical medical implants, even if its implementation might be challenging.

Comparative study on electrical properties of atomic layer deposited high-permittivity materials on silicon substrates

International Nuclear Information System (INIS)

Duenas, S.; Castan, H.; Garcia, H.; Barbolla, J.; Kukli, K.; Ritala, M.; Leskelae, M.

2005-01-01

Deep level transient spectroscopy, capacitance-voltage and conductance transient measurement techniques have been applied in order to evaluate the electrical quality of thin high-permittivity oxide layers on silicon. The oxides studied included HfO 2 film grown from two different oxygen-free metal precursors and Ta 2 O 5 and Nb 2 O 5 nanolaminates. The interface trap densities correlated to the oxide growth chemistry and semiconductor substrate treatment. No gap state densities induced by structural disorder were measured in the films grown on chemical SiO 2 . Trap densities were also clearly lower in HfO 2 films compared to Ta 2 O 5 -Nb 2 O 5

High-speed and efficient silicon modulator based on forward-biased pin diodes

Directory of Open Access Journals (Sweden)

Suguru eAkiyama

2014-11-01

Full Text Available Silicon modulators, which use the free-carrier-plasma effect, were studied, both analytically and experimentally. It was demonstrated that the loss-efficiency product, a-VpL, was a suitable figure of merit for silicon modulators that enabled their intrinsic properties to be compared. Subsequently, the dependence of VpL on frequency was expressed by using the electrical parameters of a phase shifter when the modulator was operated by assuming a simple driving configuration. A diode-based modulator operated in forward biased mode was expected from analyses to provide more efficient operation than that in reversed mode at high frequencies due to its large capacitance. We obtained an a-VpL of 9.5 dB-V at 12.5 GHz in experiments by using the fabricated phase shifter with pin diodes operated in forward biased mode. This a-VpL was comparable to the best modulators operated in depletion mode. The modulator exhibited a clear eye opening at 56 Gb/s operated by 2 V peak-to-peak signals that was achieved by incorporating such a phase shifter into a ring resonator.

A Possible Minimum Toy Model with Negative Differential Capacitance for Self-sustained Current Oscillation

International Nuclear Information System (INIS)

Xiong Gang; Sun Zhouzhou; Wang Xiangrong

2007-01-01

We generalize a simple model for superlattices to include the effect of differential capacitance. It is shown that the model always has a stable steady-state solution (SSS) if all differential capacitances are positive. On the other hand, when negative differential capacitance is included, the model can have no stable SSS and be in a self-sustained current oscillation behavior. Therefore, we find a possible minimum toy model with both negative differential resistance and negative differential capacitance which can include the phenomena of both self-sustained current oscillation and I-V oscillation of stable SSSs.

Intrinsic Low Hysteresis Touch Mode Capacitive Pressure Sensor

DEFF Research Database (Denmark)

Fragiacomo, Giulio; Pedersen, Thomas; Hansen, Ole

2011-01-01

Hysteresis has always been one of the main concerns when fabricating touch mode capacitive pressure sensors (TMCPS). This phenomenon can be fought at two different levels: during fabrication or after fabrication with the aid of a dedicated signal conditioning circuit. We will describe...... a microfabrication step that can be introduced in order to reduce drastically the hysteresis of this type of sensors without compromising their sensitivity. Medium-high range (0 to 10 bar absolute pressure) TMCPS with a capacitive signal span of over 100pF and less than 1 % hysteresis in the entire pressure range...

A multichannel portable ECG system with capacitive sensors

International Nuclear Information System (INIS)

Oehler, M; Schilling, M; Ling, V; Melhorn, K

2008-01-01

Capacitive sensors can be employed for measuring the electrocardiogram of a human heart without electric contact with the skin. This configuration avoids contact problems experienced by conventional electrocardiography. In our studies, we integrated these capacitive electrocardiogram electrodes in a 15-sensor array and combined this array with a tablet personal computer. By placing the system on the patient's body, we can measure a 15-channel electrocardiogram even through clothes and without any preparation. The goal of this development is to provide a new diagnostic tool that offers the user a reproducible, easy access to a fast and spatially resolved diagnostic 'heart view'

Capacitive sensor for continuous monitoring of high-volume droplet microfluidic generation

KAUST Repository

Conchouso Gonzalez, David

2016-12-19

This paper presents a capacitive sensor for monitoring parallel microfluidic droplet generation. The great electric permittivity difference between common droplet microfluidic fluids such as air, oil and water (ϵoil ≈ 2–3 and ϵwater ≈ 80.4), allows for accurate detection of water in oil concentration changes. Capacitance variations as large as 10 pF between a channel filled with water or dodecane, are used to continuously monitor the output of a parallelization system producing 150 µl/min of water in dodecane emulsions. We also discuss a low cost fabrication process to manufacture these capacitive sensors, which can be integrated to different substrates.

Performance relations in Capacitive Deionization systems

NARCIS (Netherlands)

Limpt, van B.

2010-01-01

Capacitive Deionization (CDI) is a relatively new deionization technology based on the temporary storage of ions on an electrically charged surface. By directing a flow between two oppositely charged surfaces, negatively charged ions will adsorb onto the positively charged surface, and positively

Comparison of gate capacitance extraction methodologies

NARCIS (Netherlands)

Kazmi, S.N.R.; Schmitz, Jurriaan

2008-01-01

In recent years, many new capacitance-voltage measurement approaches have been presented in literature. New approaches became necessary with the rapidly increasing gate current density in newer CMOS generations. Here we present a simulation platform using Silvaco software, to describe the full chain

Current Progress of Capacitive Deionization for Removal of Pollutant Ions

Science.gov (United States)

Gaikwad, Mahendra S.; Balomajumder, Chandrajit

2016-08-01

A mini review of a recently developing water purification technology capacitive deionization (CDI) applied for removal of pollutant ions is provided. The current progress of CDI for removal of different pollutant ions such as arsenic, fluoride, boron, phosphate, lithium, copper, cadmium, ferric, and nitrate ions is presented. This paper aims at motivating new research opportunities in capacitive deionization technology for removal of pollutant ions from polluted water.

Device and material characterization and analytic modeling of amorphous silicon thin film transistors

Science.gov (United States)

Slade, Holly Claudia

Hydrogenated amorphous silicon thin film transistors (TFTs) are now well-established as switching elements for a variety of applications in the lucrative electronics market, such as active matrix liquid crystal displays, two-dimensional imagers, and position-sensitive radiation detectors. These applications necessitate the development of accurate characterization and simulation tools. The main goal of this work is the development of a semi- empirical, analytical model for the DC and AC operation of an amorphous silicon TFT for use in a manufacturing facility to improve yield and maintain process control. The model is physically-based, in order that the parameters scale with gate length and can be easily related back to the material and device properties. To accomplish this, extensive experimental data and 2D simulations are used to observe and quantify non- crystalline effects in the TFTs. In particular, due to the disorder in the amorphous network, localized energy states exist throughout the band gap and affect all regimes of TFT operation. These localized states trap most of the free charge, causing a gate-bias-dependent field effect mobility above threshold, a power-law dependence of the current on gate bias below threshold, very low leakage currents, and severe frequency dispersion of the TFT gate capacitance. Additional investigations of TFT instabilities reveal the importance of changes in the density of states and/or back channel conduction due to bias and thermal stress. In the above threshold regime, the model is similar to the crystalline MOSFET model, considering the drift component of free charge. This approach uses the field effect mobility to take into account the trap states and must utilize the correct definition of threshold voltage. In the below threshold regime, the density of deep states is taken into account. The leakage current is modeled empirically, and the parameters are temperature dependent to 150oC. The capacitance of the TFT can be

Locating Depots for Capacitated Vehicle Routing

DEFF Research Database (Denmark)

Gørtz, Inge Li; Nagarajan, Viswanath

2016-01-01

We study a location-routing problem in the context of capacitated vehicle routing. The input to the k-location capacitated vehicle routing problem (k-LocVRP) consists of a set of demand locations in a metric space and a fleet of k identical vehicles, each of capacity Q. The objective is to locate k...... depots, one for each vehicle, and compute routes for the vehicles so that all demands are satisfied and the total cost is minimized. Our main result is a constant-factor approximation algorithm for k-LocVRP. In obtaining this result, we introduce a common generalization of the k-median and minimum...... spanning tree problems (called k median forest), which might be of independent interest. We give a local-search based (3+ε)-approximation algorithm for k median forest, which leads to a (12+ε)-approximation algorithm for k-LocVRP, for any constant ε>0....

Locating Depots for Capacitated Vehicle Routing

DEFF Research Database (Denmark)

Gørtz, Inge Li; Nagarajan, Viswanath

2016-01-01

depots, one for each vehicle, and compute routes for the vehicles so that all demands are satisfied and the total cost is minimized. Our main result is a constant-factor approximation algorithm for k-LocVRP. In obtaining this result, we introduce a common generalization of the k-median and minimum...... spanning tree problems (called k median forest), which might be of independent interest. We give a local-search based (3+ε)-approximation algorithm for k median forest, which leads to a (12+ε)-approximation algorithm for k-LocVRP, for any constant ε>0.......We study a location-routing problem in the context of capacitated vehicle routing. The input to the k-location capacitated vehicle routing problem (k-LocVRP) consists of a set of demand locations in a metric space and a fleet of k identical vehicles, each of capacity Q. The objective is to locate k...

Silicone metalization

Energy Technology Data Exchange (ETDEWEB)

Maghribi, Mariam N. (Livermore, CA); Krulevitch, Peter (Pleasanton, CA); Hamilton, Julie (Tracy, CA)

2008-12-09

A system for providing metal features on silicone comprising providing a silicone layer on a matrix and providing a metal layer on the silicone layer. An electronic apparatus can be produced by the system. The electronic apparatus comprises a silicone body and metal features on the silicone body that provide an electronic device.

Formation of porous silicon oxide from substrate-bound silicon rich silicon oxide layers by continuous-wave laser irradiation

Science.gov (United States)

Wang, Nan; Fricke-Begemann, Th.; Peretzki, P.; Ihlemann, J.; Seibt, M.

2018-03-01

Silicon nanocrystals embedded in silicon oxide that show room temperature photoluminescence (PL) have great potential in silicon light emission applications. Nanocrystalline silicon particle formation by laser irradiation has the unique advantage of spatially controlled heating, which is compatible with modern silicon micro-fabrication technology. In this paper, we employ continuous wave laser irradiation to decompose substrate-bound silicon-rich silicon oxide films into crystalline silicon particles and silicon dioxide. The resulting microstructure is studied using transmission electron microscopy techniques with considerable emphasis on the formation and properties of laser damaged regions which typically quench room temperature PL from the nanoparticles. It is shown that such regions consist of an amorphous matrix with a composition similar to silicon dioxide which contains some nanometric silicon particles in addition to pores. A mechanism referred to as "selective silicon ablation" is proposed which consistently explains the experimental observations. Implications for the damage-free laser decomposition of silicon-rich silicon oxides and also for controlled production of porous silicon dioxide films are discussed.

Effect of noncovalent basal plane functionalization on the quantum capacitance in graphene.

Science.gov (United States)

Ebrish, Mona A; Olson, Eric J; Koester, Steven J

2014-07-09

The concentration-dependent density of states in graphene allows the capacitance in metal-oxide-graphene structures to be tunable with the carrier concentration. This feature allows graphene to act as a variable capacitor (varactor) that can be utilized for wireless sensing applications. Surface functionalization can be used to make graphene sensitive to a particular species. In this manuscript, the effect on the quantum capacitance of noncovalent basal plane functionalization using 1-pyrenebutanoic acid succimidyl ester and glucose oxidase is reported. It is found that functionalized samples tested in air have (1) a Dirac point similar to vacuum conditions, (2) increased maximum capacitance compared to vacuum but similar to air, (3) and quantum capacitance "tuning" that is greater than that in vacuum and ambient atmosphere. These trends are attributed to reduced surface doping and random potential fluctuations as a result of the surface functionalization due to the displacement of H2O on the graphene surface and intercalation of a stable H2O layer beneath graphene that increases the overall device capacitance. The results are important for future application of graphene as a platform for wireless chemical and biological sensors.

Design, Development and Testing of a Semicircular Type Capacitive Angular Position Sensor

Directory of Open Access Journals (Sweden)

Nikhil GAURAV

2011-06-01

Full Text Available A low cost semicircular type capacitive angular position sensor has been designed, developed and tested. It is made of two semicircular parallel plates where one plate is fixed and another plate is connected with the rotor whose angular position is to be measured. When the angular position of the rotor changes with respect to the fixed plate, the overlapping area between the two plates of the capacitor is varied causing a change in capacitance value. Capacitance variation obtained due to the change in angular position is in the nano farad range. For signal conditioning, series R-L-C resonating circuit instead of conventional bridge circuit has been used to convert the sensor capacitance variation in to voltage. Experimental result shows that the capacitance for change in angular position 0º-180º increases linearly and for 180º-360º it decreases linearly. To get a linearly increasing response of same slope for the full scale of 0º-360º, a suitable linearising circuit has been designed, developed and tested. Sensor output along with the signal conditioning shows good linearity and repeatability.

Electric double-layer capacitance between an ionic liquid and few-layer graphene.

Science.gov (United States)

Uesugi, Eri; Goto, Hidenori; Eguchi, Ritsuko; Fujiwara, Akihiko; Kubozono, Yoshihiro

2013-01-01

Ionic-liquid gates have a high carrier density due to their atomically thin electric double layer (EDL) and extremely large geometrical capacitance Cg. However, a high carrier density in graphene has not been achieved even with ionic-liquid gates because the EDL capacitance CEDL between the ionic liquid and graphene involves the series connection of Cg and the quantum capacitance Cq, which is proportional to the density of states. We investigated the variables that determine CEDL at the molecular level by varying the number of graphene layers n and thereby optimising Cq. The CEDL value is governed by Cq at n 4. This transition with n indicates a composite nature for CEDL. Our finding clarifies a universal principle that determines capacitance on a microscopic scale, and provides nanotechnological perspectives on charge accumulation and energy storage using an ultimately thin capacitor.

Anomalous effects on radiation detectors and capacitance measurements inside a modified Faraday cage

Energy Technology Data Exchange (ETDEWEB)

Milián-Sánchez, V., E-mail: vicmisan@iqn.upv.es [Institute for Industrial, Radiophysical and Environmental Safety, Universitat Politècnica de València, Camino de Vera, s/n, Valencia (Spain); Mocholí-Salcedo, A., E-mail: amocholi@eln.upv.es [Traffic Control Systems Group, ITACA Institute, Universitat Politécnica de, Camino de Vera, s/n, Valencia (Spain); Milián, C., E-mail: carles.milian@cpht.polytechnique.fr [Centre de Physique Théorique, CNRS, École Polytechnique, F-91128 Palaiseau (France); Kolombet, V.A., E-mail: kolombet@iteb.ru [Institute of Theoretical and Experimental Biophysics, Russian Academy of Science, Moscow Region, Pushchino 142290 (Russian Federation); Verdú, G., E-mail: gverdu@iqn.upv.es [Institute for Industrial, Radiophysical and Environmental Safety, Universitat Politècnica de València, Camino de Vera, s/n, Valencia (Spain); Chemical and Nuclear Engineering Department, Universitat Politécnica de Valencia, Camino de Vera, s/n, Valencia (Spain)

2016-08-21

We present experimental results showing certain anomalies in the measurements performed inside a modified Faraday cage of decay rates of Ra-226, Tl-204 and Sr-90/I-90, of the gamma spectrum of a Cs-137 preparation, and of the capacitance of both a class-I multilayer ceramic capacitor and of the interconnection cable between the radiation detector and the scaler. Decay rates fluctuate significantly up to 5% around the initial value and differently depending on the type of nuclide, and the spectrum photopeak increases in 4.4%. In the case of the capacitor, direct capacitance measurements at 100 Hz, 10 kHz and 100 kHz show variations up to 0.7%, the most significant taking place at 100 Hz. In the case of the interconnection cable, the capacitance varies up to 1%. Dispersion also tends to increase inside the enclosure. However, the measured capacitance variations do not explain the variations observed in decay rates. - Highlights: • Background counts and decay rates changes of different nuclides are described. • Those changes are observed inside a multilayer modified Faraday cage. • Noise in a multichannel analyzer increases inside the multilayer enclosure. • Capacitance of a class-I multilayer ceramic capacitor varies inside the enclosure. • Capacitance changes depend on the used frequency.

Anomalous effects on radiation detectors and capacitance measurements inside a modified Faraday cage

International Nuclear Information System (INIS)

Milián-Sánchez, V.; Mocholí-Salcedo, A.; Milián, C.; Kolombet, V.A.; Verdú, G.

2016-01-01

We present experimental results showing certain anomalies in the measurements performed inside a modified Faraday cage of decay rates of Ra-226, Tl-204 and Sr-90/I-90, of the gamma spectrum of a Cs-137 preparation, and of the capacitance of both a class-I multilayer ceramic capacitor and of the interconnection cable between the radiation detector and the scaler. Decay rates fluctuate significantly up to 5% around the initial value and differently depending on the type of nuclide, and the spectrum photopeak increases in 4.4%. In the case of the capacitor, direct capacitance measurements at 100 Hz, 10 kHz and 100 kHz show variations up to 0.7%, the most significant taking place at 100 Hz. In the case of the interconnection cable, the capacitance varies up to 1%. Dispersion also tends to increase inside the enclosure. However, the measured capacitance variations do not explain the variations observed in decay rates. - Highlights: • Background counts and decay rates changes of different nuclides are described. • Those changes are observed inside a multilayer modified Faraday cage. • Noise in a multichannel analyzer increases inside the multilayer enclosure. • Capacitance of a class-I multilayer ceramic capacitor varies inside the enclosure. • Capacitance changes depend on the used frequency.

Design of planar electron gun for UHF range, CW power inductive output tube

International Nuclear Information System (INIS)

Kaushik, Meenu; Joshi, L.M.

2015-01-01

Inductive Output Tube (lOT) is an amplifier which is now-a-days in demand for scientific applications. For every vacuum tube, electron gun is an important part and in fact considered as the heart of the tube. Hence, designing of this component is very crucial for efficient operation of the device throughout its lifetime. This paper is all about the electromagnetic (EM) design of planar electron gun of 40 kV, 3.5 A beam voltage and beam current respectively, for a 100 kW CW power lOT operating in UHF range. The design considerations and basic equations involved in its design are included in the paper. The gun structure has been optimized for getting the desired beam characteristics. The simulation results including the beam profile along with the beam current are shown using two commercial codes namely TRAK and MAGIC code. Planar shape of electron beam reduces space charge forces in the beam itself and consequently beam energy spread for a given current. The magnetic focusing of planar beam is easier comparative to spherical beam hence, this structure has been adopted for this particular device design. (author)

Manganese oxide micro-supercapacitors with ultra-high areal capacitance

Science.gov (United States)

Wang, Xu; Myers, Benjamin D.; Yan, Jian; Shekhawat, Gajendra; Dravid, Vinayak; Lee, Pooi See

2013-05-01

A symmetric micro-supercapacitor is constructed by electrochemically depositing manganese oxide onto micro-patterned current collectors. High surface-to-volume ratio of manganese oxide and short diffusion distance between electrodes give an ultra-high areal capacitance of 56.3 mF cm-2 at a current density of 27.2 μA cm-2.A symmetric micro-supercapacitor is constructed by electrochemically depositing manganese oxide onto micro-patterned current collectors. High surface-to-volume ratio of manganese oxide and short diffusion distance between electrodes give an ultra-high areal capacitance of 56.3 mF cm-2 at a current density of 27.2 μA cm-2. Electronic supplementary information (ESI) available: Experimental procedures; optical images of micro-supercapacitors; areal capacitances of samples M-0.3C, M-0.6C and M-0.9C; illustration of interdigital finger electrodes; Nyquist plot of Co(OH)2 deposited on micro-electrodes. See DOI: 10.1039/c3nr00210a

CMOS MEMS capacitive absolute pressure sensor

International Nuclear Information System (INIS)

Narducci, M; Tsai, J; Yu-Chia, L; Fang, W

2013-01-01

This paper presents the design, fabrication and characterization of a capacitive pressure sensor using a commercial 0.18 µm CMOS (complementary metal–oxide–semiconductor) process and postprocess. The pressure sensor is capacitive and the structure is formed by an Al top electrode enclosed in a suspended SiO 2 membrane, which acts as a movable electrode against a bottom or stationary Al electrode fixed on the SiO 2 substrate. Both the movable and fixed electrodes form a variable parallel plate capacitor, whose capacitance varies with the applied pressure on the surface. In order to release the membranes the CMOS layers need to be applied postprocess and this mainly consists of four steps: (1) deposition and patterning of PECVD (plasma-enhanced chemical vapor deposition) oxide to protect CMOS pads and to open the pressure sensor top surface, (2) etching of the sacrificial layer to release the suspended membrane, (3) deposition of PECVD oxide to seal the etching holes and creating vacuum inside the gap, and finally (4) etching of the passivation oxide to open the pads and allow electrical connections. This sensor design and fabrication is suitable to obey the design rules of a CMOS foundry and since it only uses low-temperature processes, it allows monolithic integration with other types of CMOS compatible sensors and IC (integrated circuit) interface on a single chip. Experimental results showed that the pressure sensor has a highly linear sensitivity of 0.14 fF kPa −1 in the pressure range of 0–300 kPa. (paper)

Beating of magnetic oscillations in a graphene device probed by quantum capacitance

KAUST Repository

Tahir, M.; Schwingenschlö gl, Udo

2012-01-01

We report the quantum capacitance of a monolayergraphene device in an external perpendicular magnetic field including the effects of Rashba spin-orbit interaction(SOI). The SOI mixes the spin up and spin down states of neighbouring Landau levels into two (unequally spaced) energy branches. In order to investigate the role of the SOI for the electronic transport, we study the density of states to probe the quantum capacitance of monolayergraphene.SOIeffects on the quantum magnetic oscillations (Shubnikov de Haas and de Hass-van Alphen) are deduced from the quantum capacitance.

Beating of magnetic oscillations in a graphene device probed by quantum capacitance

KAUST Repository

Tahir, M.

2012-07-05

We report the quantum capacitance of a monolayergraphene device in an external perpendicular magnetic field including the effects of Rashba spin-orbit interaction(SOI). The SOI mixes the spin up and spin down states of neighbouring Landau levels into two (unequally spaced) energy branches. In order to investigate the role of the SOI for the electronic transport, we study the density of states to probe the quantum capacitance of monolayergraphene.SOIeffects on the quantum magnetic oscillations (Shubnikov de Haas and de Hass-van Alphen) are deduced from the quantum capacitance.

A capacitive level shifter for high voltage (2.5kV)

DEFF Research Database (Denmark)

Andersen, Thomas; Andersen, Michael A. E.; Thomsen, Ole Cornelius

2012-01-01

with focus on low power consumption as well as low capacitive load between the floating half-bridge node and ground (output capacitance). The operation of the level-shifter is tested and verified by measurements on a prototype half-bridge gate driver. Results conclude stabile operation at 2.44kV, 50k...

Atomic layer deposited TiO{sub 2} for implantable brain-chip interfacing devices

Energy Technology Data Exchange (ETDEWEB)

Cianci, E., E-mail: elena.cianci@mdm.imm.cnr.it [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (MB) (Italy); Lattanzio, S. [Istituto di Fisiologia, Dipartimento di Anatomia Umana e Fisiologia, Universita di Padova, 35131 Padova (Italy); Dipartimento di Ingegneria dell' Informazione, Universita di Padova, 35131 Padova (Italy); Seguini, G. [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (Italy); Vassanelli, S. [Istituto di Fisiologia, Dipartimento di Anatomia Umana e Fisiologia, Universita di Padova, 35131 Padova (Italy); Fanciulli, M. [Laboratorio MDM, IMM-CNR, 20864 Agrate Brianza (Italy); Dipartimento di Scienza dei Materiali, Universita degli Studi di Milano-Bicocca, 20126 Milano (Italy)

2012-05-01

In this paper we investigated atomic layer deposition (ALD) TiO{sub 2} thin films deposited on implantable neuro-chips based on electrolyte-oxide-semiconductor (EOS) junctions, implementing both efficient capacitive neuron-silicon coupling and biocompatibility for long-term implantable functionality. The ALD process was performed at 295 Degree-Sign C using titanium tetraisopropoxide and ozone as precursors on needle-shaped silicon substrates. Engineering of the capacitance of the EOS junctions introducing a thin Al{sub 2}O{sub 3} buffer layer between TiO{sub 2} and silicon resulted in a further increase of the specific capacitance. Biocompatibility for long-term implantable neuroprosthetic systems was checked upon in-vitro treatment.

Atomic layer deposited TiO2 for implantable brain-chip interfacing devices

International Nuclear Information System (INIS)

Cianci, E.; Lattanzio, S.; Seguini, G.; Vassanelli, S.; Fanciulli, M.

2012-01-01

In this paper we investigated atomic layer deposition (ALD) TiO 2 thin films deposited on implantable neuro-chips based on electrolyte-oxide-semiconductor (EOS) junctions, implementing both efficient capacitive neuron-silicon coupling and biocompatibility for long-term implantable functionality. The ALD process was performed at 295 °C using titanium tetraisopropoxide and ozone as precursors on needle-shaped silicon substrates. Engineering of the capacitance of the EOS junctions introducing a thin Al 2 O 3 buffer layer between TiO 2 and silicon resulted in a further increase of the specific capacitance. Biocompatibility for long-term implantable neuroprosthetic systems was checked upon in-vitro treatment.

Thermodynamic cycle analysis for capacitive deionization

NARCIS (Netherlands)

Biesheuvel, P.M.

2009-01-01

Capacitive deionization (CDI) is an ion removal technology based on temporarily storing ions in the polarization layers of two oppositely positioned electrodes. Here we present a thermodynamic model for the minimum work required for ion separation in the fully reversible case by describing the ionic

A New Wide Frequency Band Capacitance Transducer with Application to Measuring Metal Fill Time

Directory of Open Access Journals (Sweden)

Wael DEABES

2009-01-01

Full Text Available A novel low cost, high frequency circuit for measuring capacitance is proposed in this paper. This new capacitance measuring circuit is able to measure small coupling capacitance variations with high stray-immunity. Hence, it could be used in many potential applications such as measuring the metal fill time in the Lost Foam Casting (LFC process and Electrical Capacitive Tomography (ECT system. The proposed circuit is based on differential charging/discharging method using current feedback amplifier and a synchronous demodulation stage. The circuit has a wide high frequency operating range with zero phase shift; hence multiple circuits can work at different frequencies simultaneously to measure the capacitance. The non-ideal characteristic of the circuit has been analyzed and the results verified through LTSpice simulation. Results from the tests on a prototype and a simulation elucidate the practicality of the proposed circuit.

Capacitive MEMS-based sensors : thermo-mechanical stability and charge trapping

OpenAIRE

van Essen, M.C.

2009-01-01

Micro-Electro Mechanical Systems (MEMS) are generally characterized as miniaturized systems with electrostatically driven moving parts. In many cases, the electrodes are capacitively coupled. This basic scheme allows for a plethora of specifications and functionality. This technology has presently matured and is widely employed in industry. A voltage across the electrodes will attract the movable part. This relation between electric field and separation (or capacitance) can be conveniently em...

Oxygen defect processes in silicon and silicon germanium

KAUST Repository

Chroneos, A.

2015-06-18

Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

Oxygen defect processes in silicon and silicon germanium

KAUST Repository

Chroneos, A.; Sgourou, E. N.; Londos, C. A.; Schwingenschlö gl, Udo

2015-01-01

Silicon and silicon germanium are the archetypical elemental and alloy semiconductor materials for nanoelectronic, sensor, and photovoltaic applications. The investigation of radiation induced defects involving oxygen, carbon, and intrinsic defects is important for the improvement of devices as these defects can have a deleterious impact on the properties of silicon and silicon germanium. In the present review, we mainly focus on oxygen-related defects and the impact of isovalent doping on their properties in silicon and silicon germanium. The efficacy of the isovalent doping strategies to constrain the oxygen-related defects is discussed in view of recent infrared spectroscopy and density functional theory studies.

Compensation of the detector capacitance presented to charge-sensitive preamplifiers using the Miller effect

Energy Technology Data Exchange (ETDEWEB)

Kwon, Inyong, E-mail: iykwon@umich.edu [University of Michigan, Ann Arbor, MI (United States); Kang, Taehoon, E-mail: thnkang@umich.edu [University of Michigan, Ann Arbor, MI (United States); Wells, Byron T., E-mail: wells@galtresearch.com [Galt LLC, Ypsilanti, MI (United States); D’Aries, Lawrence J., E-mail: lawrence.j.daries.civ@mail.mil [Picatinny Arsenal, Rockaway Township, NJ (United States); Hammig, Mark D., E-mail: hammig@umich.edu [University of Michigan, Ann Arbor, MI (United States)

2015-06-01

This paper describes an integrated circuit design for a modified charge-sensitive amplifier (CSA) that compensates for the effect of capacitance presented by nuclear radiation detectors and other sensors. For applications that require large area semiconductor detectors or for those semiconductor sensors derived from high permittivity materials such as PbSe, the detector capacitance can degrade the system gain and bandwidth of a front-end preamplifier, resulting in extended rise times and attenuated output voltage signals during pulse formation. In order to suppress the effect of sensor capacitance, we applied a bootstrap technique into a traditional CSA. The technique exploits the Miller effect by reducing the effective voltage difference between the two sides of a radiation detector which minimizes the capacitance presented to the differential common-source amplifier. This new configuration is successfully designed to produce effective gain even at high detector capacitance. The entire circuit, including a core CSA with feedback components and a bootstrap amplifier, are implemented in a 0.18 μm CMOS process with a 3.3 V supply voltage. - Highlights: • A modified CSA was implemented for detector capacitance compensation. • Increasing detector capacitance degrades gain and rise time. • A bootstrap amplifier exploiting the Miller effect is described. • It allows using large area radiation sensors for high radiation-interaction rates. • Intensive noise analyses show that SNR is much better with the technique.

Capacitive performance of molybdenum nitride/titanium nitride nanotube array for supercapacitor

Energy Technology Data Exchange (ETDEWEB)

Xie, Yibing, E-mail: ybxie@seu.edu.cn; Tian, Fang

2017-01-15

Highlights: • MoN{sub x}/TiN NTA is fully converted from MoO{sub 2}/TiO{sub 2} NTA by one-step nitridation process. • MoN{sub x}/TiN NTA is used as feasible electrode material of high-performance supercapacitor. • MoN{sub x}/TiN NTA shows high capacitance, rate capability and cycling stability. - Abstract: Molybdenum nitride (MoN{sub x}) depositing on titanium nitride nanotube array (TiN NTA) was designed as MoN{sub x}/TiN NTA for supercapacitor electrode material. MoN{sub x}/TiN NTA was fabricated by electrodepositing molybdenum oxide onto titanium dioxide NTA and one-step nitridation treatment in ammonia. MoN{sub x}/TiN NTA involved top-surface layer of MoN{sub x} nanoparticles and underlying layer of TiN NTA, which contributed to electric double layer capacitance in aqueous lithium-ion electrolyte solution. The specific capacitance was increased from 69.05 mF cm{sup −2} for TiN NTA to 121.50 mF cm{sup −2} for MoN{sub x}/TiN NTA at 0.3 mA cm{sup −2}, presenting the improved capacitance performance. MoN{sub x} exhibited the capacitance of 174.83 F g{sup −1} at 1.5 A g{sup −1} and slightly declined to 109.13 F g{sup −1} at 30 A g{sup −1}, presenting high rate capability. MoN{sub x}/TiN NTA exhibited the capacitance retention ratio of 93.8% at 3.0 mA cm{sup −2} after 1000 cycles, presenting high cycling stability. MoN{sub x}/TiN NTA could act as a promising electrode material of supercapacitor.

DNA Nucleotides Detection via capacitance properties of Graphene

Science.gov (United States)

Khadempar, Nahid; Berahman, Masoud; Yazdanpanah, Arash

2016-05-01

In the present paper a new method is suggested to detect the DNA nucleotides on a first-principles calculation of the electronic features of DNA bases which chemisorbed to a graphene sheet placed between two gold electrodes in a contact-channel-contact system. The capacitance properties of graphene in the channel are surveyed using non-equilibrium Green's function coupled with the Density Functional Theory. Thus, the capacitance properties of graphene are theoretically investigated in a biological environment, and, using a novel method, the effect of the chemisorbed DNA nucleotides on electrical charges on the surface of graphene is deciphered. Several parameters in this method are also extracted including Electrostatic energy, Induced density, induced electrostatic potential, Electron difference potential and Electron difference density. The qualitative and quantitative differences among these parameters can be used to identify DNA nucleotides. Some of the advantages of this approach include its ease and high accuracy. What distinguishes the current research is that it is the first experiment to investigate the capacitance properties of gaphene changes in the biological environment and the effect of chemisorbed DNA nucleotides on the surface of graphene on the charge.

Silicon Carbide-Based Hydrogen Gas Sensors for High-Temperature Applications

Directory of Open Access Journals (Sweden)

Sangchoel Kim

2013-10-01

Full Text Available We investigated SiC-based hydrogen gas sensors with metal-insulator-semiconductor (MIS structure for high temperature process monitoring and leak detection applications in fields such as the automotive, chemical and petroleum industries. In this work, a thin tantalum oxide (Ta2O5 layer was exploited with the purpose of sensitivity improvement, because tantalum oxide has good stability at high temperature with high permeability for hydrogen gas. Silicon carbide (SiC was used as a substrate for high-temperature applications. We fabricated Pd/Ta2O5/SiC-based hydrogen gas sensors, and the dependence of their I-V characteristics and capacitance response properties on hydrogen concentrations were analyzed in the temperature range from room temperature to 500 °C. According to the results, our sensor shows promising performance for hydrogen gas detection at high temperatures.

Role of Catecholamine in Tumor Angiogenesis Linked to Capacitance Relaxation Phenomenon

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Guangyue SHI

2010-08-01

Full Text Available The present paper deals with the CgA level during metastasis linked with Capacitance relaxation phenomenon in cancer cell. CgA co-stored and correlated by exocytosis with catecholamines is a precursor to peptides that exert feedback regulatory control on catecholamine secretion. It is to be noted that CgA was the most sensitive marker for detecting patients with tumor angiogenesis. The progressive rise in CgA increases with the tumor size and this fact has been correlated with the Capacitance relaxation phenomenon (T. K. Basak, US patent No. 5691178, 1997 in different stages. The experimental results of Capacitance relaxation phenomenon were given as inputs to a model for correlation with the CgA level. This model is a control system model, the output of which is the CgA level. It is to be noted that the model is simulated in MATLAB. The expression of tumorogenisis in prostate and liver is also linked to Capacitance relaxation phenomenon in respect of its correlation with the CgA level.

Inverter-based successive approximation capacitance-to-digital converter

KAUST Repository

Omran, Hesham

2017-03-23

An energy-efficient capacitance-to-digital converter (CDC) is provided that utilizes a capacitance-domain successive approximation (SAR) technique. Unlike SAR analog- to-digital converters (ADCs), analysis shows that for SAR CDCs, the comparator offset voltage will result in signal-dependent and parasitic-dependent conversion errors, which necessitates an op-amp-based implementation. The inverter-based SAR CDC contemplated herein provides robust, energy-efficient, and fast operation. The inverter- based SAR CDC may include a hybrid coarse-fine programmable capacitor array. The design of example embodiments is insensitive to analog references, and thus achieves very low temperature sensitivity without the need for calibration. Moreover, this design achieves improved energy efficiency.

Actuatable capacitive transducer for quantitative nanoindentation combined with transmission electron microscopy

Science.gov (United States)

Warren, Oden L.; Asif, S. A. Syed; Cyrankowski, Edward; Kounev, Kalin

2010-09-21

An actuatable capacitive transducer including a transducer body, a first capacitor including a displaceable electrode and electrically configured as an electrostatic actuator, and a second capacitor including a displaceable electrode and electrically configured as a capacitive displacement sensor, wherein the second capacitor comprises a multi-plate capacitor. The actuatable capacitive transducer further includes a coupling shaft configured to mechanically couple the displaceable electrode of the first capacitor to the displaceable electrode of the second capacitor to form a displaceable electrode unit which is displaceable relative to the transducer body, and an electrically-conductive indenter mechanically coupled to the coupling shaft so as to be displaceable in unison with the displaceable electrode unit.-

A Capacitive Humidity Sensor Based on Multi-Wall Carbon Nanotubes (MWCNTs

Directory of Open Access Journals (Sweden)

Zhen-Gang Zhao

2009-09-01

Full Text Available A new type of capacitive humidity sensor is introduced in this paper. The sensor consists of two plate electrodes coated with MWCNT films and four pieces of isolating medium at the four corners of the sensor. According to capillary condensation, the capacitance signal of the sensor is sensitive to relative humidity (RH, which could be transformed to voltage signal by a capacitance to voltage converter circuit. The sensor is tested using different saturated saline solutions at the ambient temperature of 25 °C, which yielded approximately 11% to 97% RH, respectively. The function of the MWCNT films, the effect of electrode distance, the temperature character and the repeatability of the sensor are discussed in this paper.

Absolute Position Sensing Based on a Robust Differential Capacitive Sensor with a Grounded Shield Window

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Yang Bai

2016-05-01

Full Text Available A simple differential capacitive sensor is provided in this paper to measure the absolute positions of length measuring systems. By utilizing a shield window inside the differential capacitor, the measurement range and linearity range of the sensor can reach several millimeters. What is more interesting is that this differential capacitive sensor is only sensitive to one translational degree of freedom (DOF movement, and immune to the vibration along the other two translational DOFs. In the experiment, we used a novel circuit based on an AC capacitance bridge to directly measure the differential capacitance value. The experimental result shows that this differential capacitive sensor has a sensitivity of 2 × 10−4 pF/μm with 0.08 μm resolution. The measurement range of this differential capacitive sensor is 6 mm, and the linearity error are less than 0.01% over the whole absolute position measurement range.

Extrinsic and Intrinsic Frequency Dispersion of High-k Materials in Capacitance-Voltage Measurements

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S. Taylor

2012-06-01

Full Text Available In capacitance-voltage (C-V measurements, frequency dispersion in high-k dielectrics is often observed. The frequency dependence of the dielectric constant (k-value, that is the intrinsic frequency dispersion, could not be assessed before suppressing the effects of extrinsic frequency dispersion, such as the effects of the lossy interfacial layer (between the high-k thin film and silicon substrate and the parasitic effects. The effect of the lossy interfacial layer on frequency dispersion was investigated and modeled based on a dual frequency technique. The significance of parasitic effects (including series resistance and the back metal contact of the metal-oxide-semiconductor (MOS capacitor on frequency dispersion was also studied. The effect of surface roughness on frequency dispersion is also discussed. After taking extrinsic frequency dispersion into account, the relaxation behavior can be modeled using the Curie-von Schweidler (CS law, the Kohlrausch-Williams-Watts (KWW relationship and the Havriliak-Negami (HN relationship. Dielectric relaxation mechanisms are also discussed.