scholarly journals FEATURES OF KEY PARAMETERS OF FIELD TRANSISTORS

2019 ◽  
Vol 3 (2) ◽  
pp. 7-10
Author(s):  
Davron Rakhmanovich Dzhuraev ◽  
◽  
Akmal Atayevich Turaev
Keyword(s):  
High Sensitivity ◽  
Dynamic Resistance ◽  
Volume Charge ◽  
Channel Thickness ◽  
Optimal Values ◽  
Field Transistor

In this paper, the dependence of stock current on the channel closing voltage in the main parameters of the field transistor (stock), dynamic resistance and channel closing mode has been investigated. The optimal values of the channel thickness are determined depending on the thickness of the p+-n junction volume charge region of the gate and the concentration of carriers that provide high sensitivity.

Crack Velocity Measurements in Sea Ice

1994 ◽  
Vol 362 ◽  
Author(s):  
Oleg Gluschenkov ◽  
Victor Petrenko
Keyword(s):  
Sea Ice ◽  
Electrical Resistance ◽  
Crack Velocity ◽  
Electromagnetic Emission ◽  
High Sensitivity ◽  
Unfrozen Water ◽  
Dynamic Resistance ◽  
Velocity Measurements ◽  
Water Ice ◽  
Crack Dynamics

AbstractTo study crack dynamics in sea ice fast measurements of ice electrical resistance and an electromagnetic emission (EME) from cracks were used. The sample dimensions ranged from 0.05 to 30 meters. In a laboratory grown fresh water ice crack velocities varied from a few hundreds to a thousand meters per second while in the natural sea ice crack velocity was very low, about 10 m/s. This remarkable difference in the crack velocities is likely due to the dynamic resistance of unfrozen water in brine pockets and channels and to the high ductility of sea ice. It was found that the cracks propagate in ice discontinuously owing to the strong interaction with such microstructural elements as liquid inclusions and grain boundaries. The high sensitivity of the method allowed to detect nucleation of very first microcracks.

ULTRA-HIGH SENSITIVITY VANADIUM–VANADIUM SESQUIOXIDE–VANADIUM (V–V2O3–V) SYMMETRIC TUNNEL JUNCTION DIODE

2019 ◽  
Vol 26 (08) ◽  
pp. 1950041
Author(s):  
MOHAMED ABDEL-RAHMAN
Keyword(s):  
Tunnel Junction ◽  
High Sensitivity ◽  
Dynamic Resistance ◽  
Applied Bias ◽  
Current Voltage ◽  
Vanadium Sesquioxide ◽  
Theoretical Predictions ◽  
Novel Material ◽  
Junction Diode ◽  
Mim Diode

In this paper, a symmetrical MIM tunnel junction diode with a novel material combination, vanadium–vanadium sequioxide–vanadium (V–V2O3–V) is fabricated and electrically characterized. Analysis of the measured current-voltage ([Formula: see text]–[Formula: see text] characteristics of the fabricated MIM diode revealed an ultra-high diode sensitivity of [Formula: see text]9.24[Formula: see text][Formula: see text] at an applied bias of [Formula: see text]0.104[Formula: see text]V. Based on the measured [Formula: see text]–[Formula: see text] characteristics, theoretical predictions were performed showing that the diode’s dynamic resistance can be tuned for matching to coupled antennas, in rectenna structures, whilst maintaining high levels of sensitivities using practically realizable V2O3 insulator thicknesses.

scholarly journals Design and Implementation of a pH Sensor for Micro Solution Based on Nanostructured Ion-Sensitive Field-Effect Transistor

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6921
Author(s):  
Yiqing Wang ◽  
Min Yang ◽  
Chuanjian Wu
Keyword(s):  
Field Effect ◽  
Field Effect Transistor ◽  
Gate Dielectric ◽  
Dielectric Material ◽  
Ph Sensor ◽  
High Sensitivity ◽  
Fast Response ◽  
Channel Thickness ◽  
Effect Transistor ◽  
Simulation Results

pH sensors based on a nanostructured ion-sensitive field-effect transistor have characteristics such as fast response, high sensitivity and miniaturization, and they have been widely used in biomedicine, food detection and disease monitoring. However, their performance is affected by many factors, such as gate dielectric material, channel material and channel thickness. In order to obtain a pH sensor with high sensitivity and fast response, it is necessary to determine the appropriate equipment parameters, which have high processing cost and long production time. In this study, a nanostructured ion-sensitive field-effect transistor was developed based on the SILVACO technology computer-aided design (TCAD) simulator. Through experiments, we analyzed the effects of the gate dielectric material, channel material and channel thickness on the electrical characteristics of the nanostructured field-effect transistor. Based on simulation results, silicon nitride was selected as the gate dielectric layer, while indium oxide was chosen as the channel layer. The structure and parameters of the dual channel ion-sensitive field-effect transistor were determined and discussed in detail. Finally, according to the simulation results, a pH sensor based on the nanostructured ion-sensitive field-effect transistor was fabricated. The accuracy of simulation results was verified by measuring the output, transfer and pH characteristics of the device. The fabricated pH sensor had a subthreshold swing as low as 143.19 mV/dec and obtained an actual sensitivity of 88.125 mV/pH. In addition, we also tested the oxidation reaction of hydrogen peroxide catalyzed by horseradish peroxidase, and the sensitivity was up to 144.26 pA mol−1 L−1, verifying that the ion-sensitive field-effect transistor (ISFET) can be used to detect the pH of micro solution, and then combine the enzyme-linked assay to detect the concentration of protein, DNA, biochemical substances, biomarkers, etc.

scholarly journals Manifestation of the channeling effect when manufacturing JFET transistors

2020 ◽  
Vol 23 (04) ◽  
pp. 379-384
Author(s):  
V.G. Verbitskiy ◽  
◽  
S.V. Voevodin ◽  
V.V. Fedulov ◽  
G.V. Kalistyi ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Cmos Technology ◽  
Digital Circuit ◽  
Bipolar Transistors ◽  
Thin Layers ◽  
Saturation Current ◽  
Main Method ◽  
Channel Thickness ◽  
Channeling Effect ◽  
Active Base

TThe proposed work covers the tasks of such areas as reducing input currents and bias voltage of integrated operational amplifiers (ICs OA) manufactured according to BiFET technology, the prospect of using JFET transistors in digital circuit technology, Si CMOS technology at 22 nm node and beyond, manufacturing bipolar transistors on ultra-thin layers of the active base and emitter, increasing resistance of ICs to external influences. The main method of experimental investigation of channeling is the construction of impurity distribution profiles using SIMS. In this work to study the channeling effect of boron and phosphorus in silicon was chosen the method for constructing the response surface of the saturation current of JFET for a silicon wafer. The choice of method was based on the high sensitivity of the cut-off voltage and saturation current of the JFET transistor to the channel thickness and impurity concentration in it, the relative simplicity of performance and practical benefits in improving BiFET technology.

scholarly journals High Sensitivity and High Stability QCM Humidity Sensors Based on Polydopamine Coated Cellulose Nanocrystals/Graphene Oxide Nanocomposite

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2210
Author(s):  
Yao Yao ◽  
Xianhe Huang ◽  
Qiao Chen ◽  
Zhen Zhang ◽  
Weiwei Ling
Keyword(s):  
Graphene Oxide ◽  
High Stability ◽  
Humidity Sensor ◽  
High Sensitivity ◽  
Fast Response ◽  
Dynamic Resistance ◽  
Sensitive Material ◽  
Detection Range ◽  
Response And Recovery ◽  
Humidity Range

In this paper, a high sensitivity and high stability quartz crystal microbalance (QCM) humidity sensor using polydopamine (PDA) coated cellulose nanocrystal (CNC)/graphene oxide (GO) (PDA@CNC/GO) nanocomposite as sensitive material is demonstrated. The PDA@CNC was prepared by the self-polymerization action on the surface of CNC, and it acted as filler material to form functional nanocomposite with GO. The material characteristics of PDA@CNC, CNC/GO and PDA@CNC/GO were analyzed by transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The experimental results show that the introduction of PDA@CNC into GO film not only effectively enhanced the sensitivity of GO-based nanocomposite-coated QCM sensor but also significantly maintained high stability in the entire humidity range. The PDA@CNC/GO30-coated QCM humidity sensor exhibited a superior response sensitivity up to 54.66 Hz/% relative humidity (RH), while the change rate of dynamic resistance of the sensor in the humidity range of 11.3–97.3% RH is only 14% that is much smaller than that of CNC/GO-coated QCM. Besides, the effect of the PDA@CNC content on the sensitivity and stability of GO-based nanocomposite-coated QCM humidity was also studied. Moreover, other performances of PDA@CNC/GO-coated QCM humidity sensor, including humidity hysteresis, fast response and recovery and long-term stability, were systematically investigated. This work suggests that PDA@CNC/GO nanocomposite is a promising candidate material for realizing high sensitivity and high stability QCM humidity sensor in the entire humidity detection range.

Radio Measurements of Coronal Magnetic Fields

1994 ◽  
Vol 144 ◽  
pp. 21-28 ◽  
Author(s):  
G. B. Gelfreikh
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Solar Corona ◽  
Active Regions ◽  
High Sensitivity ◽  
Coronal Magnetic Field ◽  
Transverse Magnetic ◽  
Radio Sources ◽  
Radio Waves ◽  
Solar Active Regions

AbstractA review of methods of measuring magnetic fields in the solar corona using spectral-polarization observations at microwaves with high spatial resolution is presented. The methods are based on the theory of thermal bremsstrahlung, thermal cyclotron emission, propagation of radio waves in quasi-transverse magnetic field and Faraday rotation of the plane of polarization. The most explicit program of measurements of magnetic fields in the atmosphere of solar active regions has been carried out using radio observations performed on the large reflector radio telescope of the Russian Academy of Sciences — RATAN-600. This proved possible due to good wavelength coverage, multichannel spectrographs observations and high sensitivity to polarization of the instrument. Besides direct measurements of the strength of the magnetic fields in some cases the peculiar parameters of radio sources, such as very steep spectra and high brightness temperatures provide some information on a very complicated local structure of the coronal magnetic field. Of special interest are the results found from combined RATAN-600 and large antennas of aperture synthesis (VLA and WSRT), the latter giving more detailed information on twodimensional structure of radio sources. The bulk of the data obtained allows us to investigate themagnetospheresof the solar active regions as the space in the solar corona where the structures and physical processes are controlled both by the photospheric/underphotospheric currents and surrounding “quiet” corona.

Backscattered Electron Imaging of GaAs/AlGaAs Super Lattice Structures with an Ultra-High- Resolution SEM

1988 ◽  
Vol 46 ◽  
pp. 204-205
Author(s):  
Kazumichi Ogura ◽  
Michael M. Kersker
Keyword(s):  
High Resolution ◽  
Layer Structure ◽  
High Sensitivity ◽  
Beam Current ◽  
Electron Beam Current ◽  
Lattice Structures ◽  
Super Lattice ◽  
Different Types ◽  
Backscattered Electron ◽  
Electron Imaging

Backscattered electron (BE) images of GaAs/AlGaAs super lattice structures were observed with an ultra high resolution (UHR) SEM JSM-890 with an ultra high sensitivity BE detector. Three different types of super lattice structures of GaAs/AlGaAs were examined. Each GaAs/AlGaAs wafer was cleaved by a razor after it was heated for approximately 1 minute and its crosssectional plane was observed.First, a multi-layer structure of GaAs (100nm)/AlGaAs (lOOnm) where A1 content was successively changed from 0.4 to 0.03 was observed. Figures 1 (a) and (b) are BE images taken at an accelerating voltage of 15kV with an electron beam current of 20pA. Figure 1 (c) is a sketch of this multi-layer structure corresponding to the BE images. The various layers are clearly observed. The differences in A1 content between A1 0.35 Ga 0.65 As, A1 0.4 Ga 0.6 As, and A1 0.31 Ga 0.69 As were clearly observed in the contrast of the BE image.

An x-ray microprobe based upon a close-coupled focal-spot / glass capillary arrangement

1992 ◽  
Vol 50 (2) ◽  
pp. 1758-1759
Author(s):  
D. A. Carpenter ◽  
M. A. Taylor
Keyword(s):  
Imaging Techniques ◽  
Fluorescence Analysis ◽  
High Sensitivity ◽  
Specimen Preparation ◽  
X Rays ◽  
Glass Capillary ◽  
Close Coupling ◽  
X Ray ◽  
Point To Point ◽  
Beam Damage

The development of intense sources of x rays has led to renewed interest in the use of microbeams of x rays in x-ray fluorescence analysis. Sparks pointed out that the use of x rays as a probe offered the advantages of high sensitivity, low detection limits, low beam damage, and large penetration depths with minimal specimen preparation or perturbation. In addition, the option of air operation provided special advantages for examination of hydrated systems or for nondestructive microanalysis of large specimens.The disadvantages of synchrotron sources prompted the development of laboratory-based instrumentation with various schemes to maximize the beam flux while maintaining small point-to-point resolution. Nichols and Ryon developed a microprobe using a rotating anode source and a modified microdiffractometer. Cross and Wherry showed that by close-coupling the x-ray source, specimen, and detector, good intensities could be obtained for beam sizes between 30 and 100μm. More importantly, both groups combined specimen scanning with modern imaging techniques for rapid element mapping.

Ultrastructural identification of three types of sensory setae on copepod antennae

1995 ◽  
Vol 53 ◽  
pp. 956-957
Author(s):  
T. M. Weatherby ◽  
P.H. Lenz
Keyword(s):  
Phase Locking ◽  
Membrane Surface ◽  
Reaction Times ◽  
High Sensitivity ◽  
Structural Features ◽  
Calanoid Copepods ◽  
Marine Food Webs ◽  
Dendritic Membrane ◽  
Ultrastructural Characterization

Crustaceans, as well as other arthropods, are covered with sensory setae and hairs, including mechanoand chemosensory sensillae with a ciliary origin. Calanoid copepods are small planktonic crustaceans forming a major link in marine food webs. In conjunction with behavioral and physiological studies of the antennae of calanoids, we undertook the ultrastructural characterization of sensory setae on the antennae of Pleuromamma xiphias.Distal mechanoreceptive setae exhibit exceptional behavioral and physiological performance characteristics: high sensitivity (<10 nm displacements), fast reaction times (<1 msec latency) and phase locking to high frequencies (1-2 kHz). Unusual structural features of the mechanoreceptors are likely to be related to their physiological sensitivity. These features include a large number (up to 3000) of microtubules in each sensory cell dendrite, arising from or anchored to electron dense rods associated with the ciliary basal body microtubule doublets. The microtubules are arranged in a regular array, with bridges between and within rows. These bundles of microtubules extend far into each mechanoreceptive seta and terminate in a staggered fashion along the dendritic membrane, contacting a large membrane surface area and providing a large potential site of mechanotransduction.

Slow-Scan CCD Observation of Backscattering Patterns in SEM

1992 ◽  
Vol 50 (2) ◽  
pp. 1308-1309
Author(s):  
F. Ouyang ◽  
D. A. Ray ◽  
O. L. Krivanek
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Dynamic Range ◽  
High Sensitivity ◽  
Lens System ◽  
Wide Dynamic Range ◽  
Peltier Cooler ◽  
Diffraction Patterns ◽  
Scanning Electron

Electron backscattering Kikuchi diffraction patterns (BKDP) reveal useful information about the structure and orientation of crystals under study. With the well focused electron beam in a scanning electron microscope (SEM), one can use BKDP as a microanalysis tool. BKDPs have been recorded in SEMs using a phosphor screen coupled to an intensified TV camera through a lens system, and by photographic negatives. With the development of fiber-optically coupled slow scan CCD (SSC) cameras for electron beam imaging, one can take advantage of their high sensitivity and wide dynamic range for observing BKDP in SEM.We have used the Gatan 690 SSC camera to observe backscattering patterns in a JEOL JSM-840A SEM. The CCD sensor has an active area of 13.25 mm × 8.83 mm and 576 × 384 pixels. The camera head, which consists of a single crystal YAG scintillator fiber optically coupled to the CCD chip, is located inside the SEM specimen chamber. The whole camera head is cooled to about -30°C by a Peltier cooler, which permits long integration times (up to 100 seconds).

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