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Sample records for current-voltage i-v measurements

  1. Room temperature current-voltage (I-V) characteristics of Ag/InGaN/n-Si Schottky barrier diode

    Energy Technology Data Exchange (ETDEWEB)

    Erdoğan, Erman, E-mail: e.erdogan@alparslan.edu.tr [Department of Physics, Faculty of Art and Science, Muş Alparslan University, Muş 49250 (Turkey); Kundakçı, Mutlu [Department of Physics, Faculty of Science, Atatürk University, Erzurum 25240 (Turkey)

    2017-02-01

    Metal-semiconductors (MSs) or Schottky barrier diodes (SBDs) have a significant potential in the integrated device technology. In the present paper, electrical characterization of Ag/InGaN/n-Si Schottky diode have been systematically carried out by simple Thermionic method (TE) and Norde function based on the I-V characteristics. Ag ohmic and schottky contacts are deposited on InGaN/n-Si film by thermal evaporation technique under a vacuum pressure of 1×10{sup −5} mbar. Ideality factor, barrier height and series resistance values of this diode are determined from I-V curve. These parameters are calculated by TE and Norde methods and findings are given in a comparetive manner. The results show the consistency for both method and also good agreement with other results obtained in the literature. The value of ideality factor and barrier height have been determined to be 2.84 and 0.78 eV at room temperature using simple TE method. The value of barrier height obtained with Norde method is calculated as 0.79 eV.

  2. Room temperature current-voltage (I-V) characteristics of Ag/InGaN/n-Si Schottky barrier diode

    Science.gov (United States)

    Erdoğan, Erman; Kundakçı, Mutlu

    2017-02-01

    Metal-semiconductors (MSs) or Schottky barrier diodes (SBDs) have a significant potential in the integrated device technology. In the present paper, electrical characterization of Ag/InGaN/n-Si Schottky diode have been systematically carried out by simple Thermionic method (TE) and Norde function based on the I-V characteristics. Ag ohmic and schottky contacts are deposited on InGaN/n-Si film by thermal evaporation technique under a vacuum pressure of 1×10-5 mbar. Ideality factor, barrier height and series resistance values of this diode are determined from I-V curve. These parameters are calculated by TE and Norde methods and findings are given in a comparetive manner. The results show the consistency for both method and also good agreement with other results obtained in the literature. The value of ideality factor and barrier height have been determined to be 2.84 and 0.78 eV at room temperature using simple TE method. The value of barrier height obtained with Norde method is calculated as 0.79 eV.

  3. Classification of methods for measuring current-voltage characteristics of semiconductor devices

    Directory of Open Access Journals (Sweden)

    Iermolenko Ia. O.

    2014-06-01

    Full Text Available It is shown that computer systems for measuring current-voltage characteristics are very important for semiconductor devices production. The main criteria of efficiency of such systems are defined. It is shown that efficiency of such systems significantly depends on the methods for measuring current-voltage characteristics of semiconductor devices. The aim of this work is to analyze existing methods for measuring current-voltage characteristics of semiconductor devices and to create the classification of these methods in order to specify the most effective solutions in terms of defined criteria. To achieve this aim, the most common classifications of methods for measuring current-voltage characteristics of semiconductor devices and their main disadvantages are considered. Automated and manual, continuous, pulse, mixed, isothermal and isodynamic methods for measuring current-voltage characteristics are analyzed. As a result of the analysis and generalization of existing methods the next classification criteria are defined: the level of automation, the form of measurement signals, the condition of semiconductor device during the measurements, and the use of mathematical processing of the measurement results. With the use of these criteria the classification scheme of methods for measuring current-voltage characteristics of semiconductor devices is composed and the most effective methods are specified.

  4. Effects of synchronous irradiance monitoring and correction of current-voltage curves on the outdoor performance measurements of photovoltaic modules

    Science.gov (United States)

    Hishikawa, Yoshihiro; Doi, Takuya; Higa, Michiya; Ohshima, Hironori; Takenouchi, Takakazu; Yamagoe, Kengo

    2017-08-01

    Precise outdoor measurement of the current-voltage (I-V) curves of photovoltaic (PV) modules is desired for many applications such as low-cost onsite performance measurement, monitoring, and diagnosis. Conventional outdoor measurement technologies have a problem in that their precision is low when the solar irradiance is unstable, hence, limiting the opportunity of precise measurement only on clear sunny days. The purpose of this study is to investigate an outdoor measurement procedure, that can improve both the measurement opportunity and precision. Fast I-V curve measurements within 0.2 s and synchronous measurement of irradiance using a PV module irradiance sensor very effectively improved the precision. A small standard deviation (σ) of the module’s maximum output power (P max) in the range of 0.7-0.9% is demonstrated, based on the basis of a 6 month experiment, that mainly includes partly sunny days and cloudy days, during which the solar irradiance is unstable. The σ was further improved to 0.3-0.5% by correcting the curves for the small variation of irradiance. This indicates that the procedure of this study enables much more reproducible I-V curve measurements than a conventional usual procedure under various climatic conditions. Factors that affect measurement results are discussed, to further improve the precision.

  5. Possible influence of the voltage dependence of the Josephson tunneling current I(V,psi) on the corresponding current-voltage characteristic

    International Nuclear Information System (INIS)

    Hahlbohm, H.D.; Luebbig, H.; Luther, H.

    1975-01-01

    Analog computer calculations of the current-voltage characteristic involving the voltage dependence of the amplitudes of the tunneling current equation explicitly, for the case of a current driven tunneling junction at different temperatures are reported on. These studies are based upon the adiabatic representation of the current-phase relation. The influence of retarding effects is not included. Therefore the computational results can lead to practical consequences at best in the range near the transition temperature. (Auth.)

  6. The Role of Interface States and Series Resistance on the Current Voltage (I-V) Characterises of Au/n-CdTe Solar Cells

    International Nuclear Information System (INIS)

    Fiat, S.

    2008-01-01

    In order to well interpret the experimentally observed nonideal Au/n-CdTe solar cells parameters such as the zero-bias barrier height ( Φ B o), ideality factor (n), interface states (Nss) and series resistance. The energy distribution profile of Nss was obtained from forward bias I-V characteristics by taking in to account the bias dependent of the effective barrier height (Φ e )at room temperature.The values of Rs obtained from Cheung's functions. The higher values of n and Rs were attributed to the existence of a native insulator layer on CdTe surface and to high density of Nss localized at semiconductor/ insulator layer interface. The experimental I-V characteristics confirmed that the the thickness of insulator layer (δ o x) ,magnitude or Rs and Nss and a particular distribution of Nss in the band gap are important parameters that influence the electrical parameters of Au/n-CdTe solar cells

  7. {sup 60}Co {gamma} irradiation effects on the current-voltage (I-V) characteristics of Al/SiO{sub 2}/p-Si (MIS) Schottky diodes

    Energy Technology Data Exchange (ETDEWEB)

    Tataroglu, A. [Department of Physics, Faculty of Arts and Sciences, Gazi University 06500, Ankara (Turkey)]. E-mail: ademt@gazi.edu.tr; Altindal, S. [Department of Physics, Faculty of Arts and Sciences, Gazi University 06500, Ankara (Turkey); Buelbuel, M.M. [Department of Physics, Faculty of Arts and Sciences, Gazi University 06500, Ankara (Turkey)

    2006-12-01

    It is well known that the exposure of any semiconductor surfaces to the {sup 60}Co {gamma}-ray irradiation causes electrically active defects. To investigate the effect of {gamma}-ray irradiation dose on the electrical characteristics of metal-insulator-semiconductor (MIS) Schottky diodes, the fabricated devices were exposed to {gamma} radiation at a dose of 2.12 kGy/h. The total dose range was from 0 to 450 kGy at room temperature. The density of interface states N {sub ss} as a function of E {sub ss}-E {sub v}, the values of series resistance R {sub s} and the bias dependence of the effective barrier height {phi} {sub e} for each dose were obtained from the forward bias I-V characteristics. Experimental results show that the {gamma}-irradiation gives rise to an increase in the zero bias barrier height {phi} {sub BO}, as the ideality factor n, R {sub s} and N {sub ss} decreases with increasing radiation dose.

  8. Monitoring and Fault Detection in Photovoltaic Systems Based On Inverter Measured String I-V Curves

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Kerekes, Tamas

    2015-01-01

    Most photovoltaic (PV) string inverters have the hardware capability to measure at least part of the current-voltage (I-V) characteristic curve of the PV strings connected at the input. However, this intrinsic capability of the inverters is not used, since I-V curve measurement and monitoring...... functions are not implemented in the inverter control software. In this paper, we aim to show how such a functionality can be useful for PV system monitoring purposes, to detect the presence and cause of power-loss in the PV strings, be it due to shading, degradation of the PV modules or balance......-of-system components through increased series resistance losses, or shunting of the PV modules. To achieve this, we propose and experimentally demonstrate three complementary PV system monitoring methods that make use of the I-V curve measurement capability of a commercial string inverter. The first method is suitable...

  9. Current-voltage curves of gold quantum point contacts revisited

    DEFF Research Database (Denmark)

    Hansen, K.; Nielsen, S K.; Brandbyge, Mads

    2000-01-01

    We present measurements of current-voltage (I-V) curves on gold quantum point contacts (QPCs) with a conductance up to 4 G(0) (G(0) = 2e(2)/h is the conductance quantum) and voltages up to 2 V. The QPCs are formed between the gold tip of a scanning tunneling microscope and a Au(110) surface under...

  10. Evaluation of the Electronic Structure of Single-Molecule Junctions Based on Current-Voltage and Thermopower Measurements: Application to C60 Single-Molecule Junction.

    Science.gov (United States)

    Komoto, Yuki; Isshiki, Yuji; Fujii, Shintaro; Nishino, Tomoaki; Kiguchi, Manabu

    2017-02-16

    The electronic structure of molecular junctions has a significant impact on their transport properties. Despite the decisive role of the electronic structure, a complete characterization of the electronic structure remains a challenge. This is because there is no straightforward way of measuring electron spectroscopy for an individual molecule trapped in a nanoscale gap between two metal electrodes. Herein, a comprehensive approach to obtain a detailed description of the electronic structure in single-molecule junctions based on the analysis of current-voltage (I-V) and thermoelectric characteristics is described. It is shown that the electronic structure of the prototypical C 60 single-molecule junction can be resolved by analyzing complementary results of the I-V and thermoelectric measurement. This combined approach confirmed that the C 60 single-molecule junction was highly conductive with molecular electronic conductances of 0.033 and 0.003 G 0 and a molecular Seebeck coefficient of -12 μV K -1 . In addition, we revealed that charge transport was mediated by a LUMO whose energy level was located 0.5≈0.6 eV above the Fermi level of the Au electrode. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Measurement and statistical analysis of single-molecule current-voltage characteristics, transition voltage spectroscopy, and tunneling barrier height.

    Science.gov (United States)

    Guo, Shaoyin; Hihath, Joshua; Díez-Pérez, Ismael; Tao, Nongjian

    2011-11-30

    We report on the measurement and statistical study of thousands of current-voltage characteristics and transition voltage spectra (TVS) of single-molecule junctions with different contact geometries that are rapidly acquired using a new break junction method at room temperature. This capability allows one to obtain current-voltage, conductance voltage, and transition voltage histograms, thus adding a new dimension to the previous conductance histogram analysis at a fixed low-bias voltage for single molecules. This method confirms the low-bias conductance values of alkanedithiols and biphenyldithiol reported in literature. However, at high biases the current shows large nonlinearity and asymmetry, and TVS allows for the determination of a critically important parameter, the tunneling barrier height or energy level alignment between the molecule and the electrodes of single-molecule junctions. The energy level alignment is found to depend on the molecule and also on the contact geometry, revealing the role of contact geometry in both the contact resistance and energy level alignment of a molecular junction. Detailed statistical analysis further reveals that, despite the dependence of the energy level alignment on contact geometry, the variation in single-molecule conductance is primarily due to contact resistance rather than variations in the energy level alignment.

  12. Current-voltage characteristics of single-molecule diarylethene junctions measured with adjustable gold electrodes in solution.

    Science.gov (United States)

    Briechle, Bernd M; Kim, Youngsang; Ehrenreich, Philipp; Erbe, Artur; Sysoiev, Dmytro; Huhn, Thomas; Groth, Ulrich; Scheer, Elke

    2012-01-01

    We report on an experimental analysis of the charge transport through sulfur-free photochromic molecular junctions. The conductance of individual molecules contacted with gold electrodes and the current-voltage characteristics of these junctions are measured in a mechanically controlled break-junction system at room temperature and in liquid environment. We compare the transport properties of a series of molecules, labeled TSC, MN, and 4Py, with the same switching core but varying side-arms and end-groups designed for providing the mechanical and electrical contact to the gold electrodes. We perform a detailed analysis of the transport properties of TSC in its open and closed states. We find rather broad distributions of conductance values in both states. The analysis, based on the assumption that the current is carried by a single dominating molecular orbital, reveals distinct differences between both states. We discuss the appearance of diode-like behavior for the particular species 4Py that features end-groups, which preferentially couple to the metal electrode by physisorption. We show that the energetic position of the molecular orbital varies as a function of the transmission. Finally, we show for the species MN that the use of two cyano end-groups on each side considerably enhances the coupling strength compared to the typical behavior of a single cyano group.

  13. The I-V Measurement System for Solar Cells Based on MCU

    International Nuclear Information System (INIS)

    Chen Fengxiang; Ai Yu; Wang Jiafu; Wang Lisheng

    2011-01-01

    In this paper, an I-V measurement system for solar cells based on Single-chip Microcomputer (MCU) is presented. According to the test principles of solar cells, this measurement system mainly comprises of two parts-data collecting, data processing and displaying. The MCU mainly used as to acquire data, then the collecting results is sent to the computer by serial port. The I-V measurement results of our test system are shown in the human-computer interaction interface based on our hardware circuit. By comparing the test results of our I-V tester and the results of other commercial I-V tester, we found errors for most parameters are less than 5%, which shows our I-V test result is reliable. Because the MCU can be applied in many fields, this I-V measurement system offers a simple prototype for portable I-V tester for solar cells.

  14. The I-V Measurement System for Solar Cells Based on MCU

    Energy Technology Data Exchange (ETDEWEB)

    Chen Fengxiang; Ai Yu; Wang Jiafu; Wang Lisheng, E-mail: phonixchen79@yahoo.com.cn [Department of physics science and technology, Wuhan University of Technology, Wuhan city, Hubei Province, 430070 (China)

    2011-02-01

    In this paper, an I-V measurement system for solar cells based on Single-chip Microcomputer (MCU) is presented. According to the test principles of solar cells, this measurement system mainly comprises of two parts-data collecting, data processing and displaying. The MCU mainly used as to acquire data, then the collecting results is sent to the computer by serial port. The I-V measurement results of our test system are shown in the human-computer interaction interface based on our hardware circuit. By comparing the test results of our I-V tester and the results of other commercial I-V tester, we found errors for most parameters are less than 5%, which shows our I-V test result is reliable. Because the MCU can be applied in many fields, this I-V measurement system offers a simple prototype for portable I-V tester for solar cells.

  15. Current-Voltage Characteristics of Quasi-One-Dimensional Superconductors

    DEFF Research Database (Denmark)

    Vodolazov, D.Y.; Peeters, F.M.; Piraux, L.

    2003-01-01

    The current-voltage (I-V) characteristics of quasi-one-dimensional superconductors were discussed. The I-V characteristics exhibited an unusual S behavior. The dynamics of superconducting condensate and the existence of two different critical currents resulted in such an unusual behavior....

  16. Distribution of barrier heights in Au/porous GaAs Schottky diodes from current-voltage-temperature measurements

    International Nuclear Information System (INIS)

    Harrabi, Z.; Jomni, S.; Beji, L.; Bouazizi, A.

    2010-01-01

    In this work, we have studied the electrical characteristics of the Au/porous GaAs/p-GaAs diodes as a function of temperature. The (I-V)-T characteristics are analysed on the basis of thermionic emission (TE). The temperature behaviour of the barrier height potential and the ideality factor demonstrate that the current transport is controlled by the thermionic emission mechanism (TE) with Gaussian distribution of the barrier height potential. The Gaussian distribution of barrier height potential is due to barrier inhomogeneity, which is suggested to be caused by the presence of the porous GaAs interfacial layer. The experimental (I-V)-T characteristics of the Au/porous GaAs/p-GaAs heterostructure demonstrate the presence of a two Gaussian distributions having a mean barrier height potential Φ b0 -bar of about 0.67 and 0.54 V and standard deviations σ s 2 of about 8.4x10 -3 and 4.2x10 -3 V, respectively. Using the obtained standard deviation, the obtained Richardson constant value is in accordance with the well documented value (79.2 A cm -2 K -2 ) of p-type GaAs and the mean barrier height Φ b0 -bar is closed to the band gap of GaAs. The obtained values prove that the I-V-T characteristics of Au/porous GaAs/p-GaAs heterostructure are governed by the TE mechanism theory with two Gaussian distributions of barrier heights.

  17. Current-voltage characteristics of dendrimer light-emitting diodes

    International Nuclear Information System (INIS)

    Stevenson, S G; Samuel, I D W; Staton, S V; Knights, K A; Burn, P L; Williams, J H T; Walker, Alison B

    2010-01-01

    We have investigated current-voltage (I-V) characteristics of unipolar and bipolar organic diodes that use phosphorescent dendrimers as the emissive organic layer. Through simulation of the measured I-V characteristics we were able to determine the device parameters for each device structure studied, leading to a better understanding of injection and transport behaviour in these devices. It was found that the common practice of assuming injection barriers are equal to the difference between bare electrode work functions and molecular orbital levels is unsuitable for the devices considered here, particularly for gold contacts. The studies confirm that different aromatic units in the dendrons can give significant differences in the charge transporting properties of the dendrimers.

  18. Current-voltage characteristics of dendrimer light-emitting diodes

    Science.gov (United States)

    Stevenson, S. G.; Samuel, I. D. W.; Staton, S. V.; Knights, K. A.; Burn, P. L.; Williams, J. H. T.; Walker, Alison B.

    2010-09-01

    We have investigated current-voltage (I-V) characteristics of unipolar and bipolar organic diodes that use phosphorescent dendrimers as the emissive organic layer. Through simulation of the measured I-V characteristics we were able to determine the device parameters for each device structure studied, leading to a better understanding of injection and transport behaviour in these devices. It was found that the common practice of assuming injection barriers are equal to the difference between bare electrode work functions and molecular orbital levels is unsuitable for the devices considered here, particularly for gold contacts. The studies confirm that different aromatic units in the dendrons can give significant differences in the charge transporting properties of the dendrimers.

  19. Current-voltage characteristics of dendrimer light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Stevenson, S G; Samuel, I D W [Organic Semiconductor Centre, SUPA, School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife, KY16 9SS (United Kingdom); Staton, S V; Knights, K A; Burn, P L [Department of Chemistry, Chemistry Research Laboratory, 12 Mansfield Road, Oxford, OX1 3TA (United Kingdom); Williams, J H T; Walker, Alison B, E-mail: a.b.walker@bath.ac.u [Department of Physics, University of Bath, Bath, BA2 7AY (United Kingdom)

    2010-09-29

    We have investigated current-voltage (I-V) characteristics of unipolar and bipolar organic diodes that use phosphorescent dendrimers as the emissive organic layer. Through simulation of the measured I-V characteristics we were able to determine the device parameters for each device structure studied, leading to a better understanding of injection and transport behaviour in these devices. It was found that the common practice of assuming injection barriers are equal to the difference between bare electrode work functions and molecular orbital levels is unsuitable for the devices considered here, particularly for gold contacts. The studies confirm that different aromatic units in the dendrons can give significant differences in the charge transporting properties of the dendrimers.

  20. An investigation of characteristics parameters of Ag/p-Si Schottky diodes based on I-V-T and C-V-T measurements

    International Nuclear Information System (INIS)

    Selcuk, A.B.

    2004-01-01

    The current-voltage (I-V) measurements on Ag/p-Si Schottky barrier diodes in the temperature range 125-300 K were carried out. The experimental values of n and Φ b 0 were determined from intercepts and slopes of the forward bias In I-V plot at each temperature. The Φ b 0 and n determined from semilog-forwaid I- V plots were found to be a strong function of temperature. The ideality factor n was found to increase, while the Φ b 0 decrease with decreasing temperature. The flat-band barrier height Φ b f and series resistance R s are also determined from the I-V measurements. Furthermore, the diffusion potential V D , experimental carrier doping density N A , Fermi level E F and barrier height Φ C V are determined from the C- V measurements. It is shown that the values of R s estimated from Cheung's method were strongly temperature dependent decreased with increasing temperature

  1. Fault identification in crystalline silicon PV modules by complementary analysis of the light and dark current-voltage characteristics

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Hacke, Peter

    2014-01-01

    Photovoltaic system (PV) maintenance and diagnostic tools are often based on performance models of the system, complemented with light current-voltage (I-V) measurements, visual inspection and/or thermal imaging. Although these are invaluable tools in diagnosing PV system performance losses and f...

  2. Current-voltage characterization of individual as-grown nanowires using a scanning tunneling microscope.

    Science.gov (United States)

    Timm, Rainer; Persson, Olof; Engberg, David L J; Fian, Alexander; Webb, James L; Wallentin, Jesper; Jönsson, Andreas; Borgström, Magnus T; Samuelson, Lars; Mikkelsen, Anders

    2013-11-13

    Utilizing semiconductor nanowires for (opto)electronics requires exact knowledge of their current-voltage properties. We report accurate on-top imaging and I-V characterization of individual as-grown nanowires, using a subnanometer resolution scanning tunneling microscope with no need for additional microscopy tools, thus allowing versatile application. We form Ohmic contacts to InP and InAs nanowires without any sample processing, followed by quantitative measurements of diameter dependent I-V properties with a very small spread in measured values compared to standard techniques.

  3. Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

    Science.gov (United States)

    Saive, Rebecca; Mueller, Christian; Schinke, Janusz; Lovrincic, Robert; Kowalsky, Wolfgang

    2013-12-01

    We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces.

  4. Understanding S-shaped current-voltage characteristics of organic solar cells: Direct measurement of potential distributions by scanning Kelvin probe

    International Nuclear Information System (INIS)

    Saive, Rebecca; Kowalsky, Wolfgang; Mueller, Christian; Schinke, Janusz; Lovrincic, Robert

    2013-01-01

    We present a comparison of the potential distribution along the cross section of bilayer poly(3-hexylthiophene)/1-(3-methoxycarbonyl)propyl-1-phenyl[6,6]C61 (P3HT/PCBM) solar cells, which show normal and anomalous, S-shaped current-voltage (IV) characteristics. We expose the cross sections of the devices with a focussed ion beam and measure them with scanning Kelvin probe microscopy. We find that in the case of S-shaped IV-characteristics, there is a huge potential drop at the PCBM/Al top contact, which does not occur in solar cells with normal IV-characteristics. This behavior confirms the assumption that S-shaped curves are caused by hindered charge transport at interfaces

  5. Comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element

    International Nuclear Information System (INIS)

    Wernsman, Bernard

    1997-01-01

    A comparison between steady-state and dynamic I-V measurements from a single-cell thermionic fuel element (TFE) is made. The single-cell TFE used in this study is the prototype for the 40 kW e space nuclear power system that is similar to the 6 kW e TOPAZ-II. The steady-state I-V measurements influence the emitter temperature due to electron cooling. Therefore, to eliminate the steady-state I-V measurement influence on the TFE and provide a better understanding of the behavior of the thermionic energy converter and TFE characteristics, dynamic I-V measurements are made. The dynamic I-V measurements are made at various input power levels, cesium pressures, collector temperatures, and steady-state current levels. From these measurements, it is shown that the dynamic I-V's do not change the TFE characteristics at a given operating point. Also, the evaluation of the collector work function from the dynamic I-V measurements shows that the collector optimization is not due to a minimum in the collector work function but due to an emission optimization. Since the dynamic I-V measurements do not influence the TFE characteristics, it is believed that these measurements can be done at a system level to understand the influence of TFE placement in the reactor as a function of the core thermal distribution

  6. Current voltage perspective of an organic electronic device

    Science.gov (United States)

    Mukherjee, Ayash K.; Kumari, Nikita

    2018-05-01

    Nonlinearity in current (I) - voltage (V) measurement is a well-known attribute of two-terminal organic device, irrespective of the geometrical or structural arrangement of the device. Most of the existing theories that are developed for interpretation of I-V data, either focus current-voltage relationship of charge injection mechanism across the electrode-organic material interface or charge transport mechanism through the organic active material. On the contrary, both the mechanisms work in tandem charge conduction through the device. The transport mechanism is further complicated by incoherent scattering from scattering centres/charge traps that are located at the electrode-organic material interface and in the bulk of organic material. In the present communication, a collective expression has been formulated that comprises of all the transport mechanisms that are occurring at various locations of a planar organic device. The model has been fitted to experimental I-V data of Au/P3HT/Au device with excellent degree of agreement. Certain physical parameters such as the effective area of cross-section and resistance due to charge traps have been extracted from the fit.

  7. Current-voltage characteristics of carbon nanotubes with substitutional nitrogen

    DEFF Research Database (Denmark)

    Kaun, C.C.; Larade, B.; Mehrez, H.

    2002-01-01

    unit cell generates a metallic transport behavior. Nonlinear I-V characteristics set in at high bias and a negative differential resistance region is observed for the doped tubes. These behaviors can be well understood from the alignment/mis-alignment of the current carrying bands in the nanotube leads......We report ab initio analysis of current-voltage (I-V) characteristics of carbon nanotubes with nitrogen substitution doping. For zigzag semiconducting tubes, doping with a single N impurity increases current flow and, for small radii tubes, narrows the current gap. Doping a N impurity per nanotube...

  8. Current-Voltage Characteristics of the Metal / Organic Semiconductor / Metal Structures: Top and Bottom Contact Configuration Case

    Directory of Open Access Journals (Sweden)

    Šarūnas MEŠKINIS

    2013-03-01

    Full Text Available In present study five synthesized organic semiconductor compounds have been used for fabrication of the planar metal / organic semiconductor / metal structures. Both top electrode and bottom electrode configurations were used. Current-voltage (I-V characteristics of the samples were investigated. Effect of the hysteresis of the I-V characteristics was observed for all the investigated samples. However, strength of the hysteresis was dependent on the organic semiconductor used. Study of I-V characteristics of the top contact Al/AT-RB-1/Al structures revealed, that in (0 – 500 V voltages range average current of the samples measured in air is only slightly higher than current measured in nitrogen ambient. Deposition of the ultra-thin diamond like carbon interlayer resulted in both decrease of the hysteresis of I-V characteristics of top contact Al/AT-RB-1/Al samples. However, decreased current and decreased slope of the I-V characteristics of the samples with diamond like carbon interlayer was observed as well. I-V characteristic hysteresis effect was less pronounced in the case of the bottom contact metal/organic semiconductor/metal samples. I-V characteristics of the bottom contact samples were dependent on electrode metal used.DOI: http://dx.doi.org/10.5755/j01.ms.19.1.3816

  9. Advanced In Situ I-V Measurements Used in the Study of Porous Structures Growth on Silicon

    Directory of Open Access Journals (Sweden)

    Amare Benor

    2017-01-01

    Full Text Available The rate of oxide formation during growth of pores structures on silicon was investigated by in situ I-V measurements. The measurements were designed to get two I-V curves in a short time (total time for the two measurements was 300 seconds taking into account the gap (in mA/cm2 for each corresponding voltage. The in situ I-V measurements were made at different pore depth/time, at the electrolyte-pore tip interface, while etching takes place based on p-type Si. The results showed increasing, decreasing, and constant I-V gap in time, for macropores, nanopores, and electropolishing regimes, respectively. This was related to the expected diffusion limitation of oxide forming (H2O molecules reaching the electrolyte-pore tip and the anodizing current, while etching takes place. The method can be developed further and has the potential to be applied in other electrochemically etched porous semiconductor materials.

  10. Current-voltage curves of atomic-sized transition metal contacts: An explanation of why Au is ohmic and Pt is not

    DEFF Research Database (Denmark)

    Nielsen, S.K.; Brandbyge, Mads; Hansen, K.

    2002-01-01

    We present an experimental study of current-voltage (I-V) curves on atomic-sized Au and Pt contacts formed under cryogenic vacuum (4.2 K). Whereas I-V curves for Au are almost Ohmic, the conductance G=I/V for Pt decreases with increasing voltage, resulting in distinct nonlinear I-V behavior...

  11. Comment on 'Temperature dependence of the current-voltage characteristics of Sn/PANI/p-Si/Al heterojunctions'

    Energy Technology Data Exchange (ETDEWEB)

    Pipinys, P; Rimeika, A [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania)], E-mail: ftfdekanas@vpu.lt

    2008-02-27

    Current-voltage characteristics of Sn/PANI/p-Si/Al heterojunctions, measured in the temperature range 140-280 K by Kaya et al (2007 J. Phys.: Condens. Matter 19 406205), are reinterpreted in the framework of phonon-assisted tunnelling theory, as a free-charge-carrier generation mechanism in the strong electrical field. It is shown that phonon-assisted tunnelling more adequately describes the peculiarities of the variation of I-V data with temperature in PANI polymers. (comment)

  12. Morphology and current-voltage characteristics of nanostructured pentacene thin films probed by atomic force microscopy.

    Science.gov (United States)

    Zorba, S; Le, Q T; Watkins, N J; Yan, L; Gao, Y

    2001-09-01

    Atomic force microscopy was used to study the growth modes (on SiO2, MoS2, and Au substrates) and the current-voltage (I-V) characteristics of organic semiconductor pentacene. Pentacene films grow on SiO2 substrate in a layer-by-layer manner with full coverage at an average thickness of 20 A and have the highest degree of molecular ordering with large dendritic grains among the pentacene films deposited on the three different substrates. Films grown on MoS2 substrate reveal two different growth modes, snowflake-like growth and granular growth, both of which seem to compete with each other. On the other hand, films deposited on Au substrate show granular structure for thinner coverages (no crystal structure) and dendritic growth for higher coverages (crystal structure). I-V measurements were performed with a platinum tip on a pentacene film deposited on a Au substrate. The I-V curves on pentacene film reveal symmetric tunneling type character. The field dependence of the current indicates that the main transport mechanism at high field intensities is hopping (Poole-Frenkel effect). From these measurements, we have estimated a field lowering coefficient of 9.77 x 10(-6) V-1/2 m1/2 and an ideality factor of 18 for pentacene.

  13. Current-voltage temperature characteristics of Au/n-Ge (1 0 0) Schottky diodes

    Energy Technology Data Exchange (ETDEWEB)

    Chawanda, Albert, E-mail: albert.chawanda@up.ac.za [Midlands State University, Bag 9055 Gweru (Zimbabwe); University of Pretoria, 0002 Pretoria (South Africa); Mtangi, Wilbert; Auret, Francois D; Nel, Jacqueline [University of Pretoria, 0002 Pretoria (South Africa); Nyamhere, Cloud [Nelson Mandela Metropolitan University, Port Elizabeth (South Africa); Diale, Mmantsae [University of Pretoria, 0002 Pretoria (South Africa)

    2012-05-15

    The variation in electrical characteristics of Au/n-Ge (1 0 0) Schottky contacts have been systematically investigated as a function of temperature using current-voltage (I-V) measurements in the temperature range 140-300 K. The I-V characteristics of the diodes indicate very strong temperature dependence. While the ideality factor n decreases, the zero-bias Schottky barrier height (SBH) ({Phi}{sub B}) increases with the increasing temperature. The I-V characteristics are analyzed using the thermionic emission (TE) model and the assumption of a Gaussian distribution of the barrier heights due to barrier inhomogeneities at the metal-semiconductor interface. The zero-bias barrier height {Phi}{sub B} vs. 1/2 kT plot has been used to show the evidence of a Gaussian distribution of barrier heights and values of {Phi}{sub B}=0.615 eV and standard deviation {sigma}{sub s0}=0.0858 eV for the mean barrier height and zero-bias standard deviation have been obtained from this plot, respectively. The Richardson constant and the mean barrier height from the modified Richardson plot were obtained as 1.37 A cm{sup -2} K{sup -2} and 0.639 eV, respectively. This Richardson constant is much smaller than the reported of 50 A cm{sup -2} K{sup -2}. This may be due to greater inhomogeneities at the interface.

  14. Compensation and trapping in CdZnTe radiation detectors studied by thermoelectric emission spectroscopy, thermally stimulated conductivity, and current-voltage measurements

    International Nuclear Information System (INIS)

    James, Ralph B.

    2000-01-01

    In today's commercially available counter-select-grade CdZnTe crystals for radiation detector applications, the thermal ionization energies of the traps and their types, whether electron or hole traps, were measured. The measurements were successfully done using thermoelectric emission spectroscopy (TEES) and thermally stimulated conductivity (TSC). For reliability, the electrical contacts to the sample were found to be very important and, instead of Au Schottky contacts, In Ohmic contacts had to be used. For the filling of the traps, photoexcitation was done at zero bias, at 20K and at wavelengths which gave the maximum bulk photoexcitation for the sample. Between the temperature range from 20 to 400 K, the TSC current was found to be on the order of ∼ 10,000 times or even larger than the TEES current, in agreement with theory, but only TEES could resolve the trap type and was sensitive to the deep traps. Large concentration of hole traps at 0.1 and 0.6 eV were observed and smaller contraction of electron traps at 0.4 eV was seen. These deep traps cause compensation in the material and also cause trapping that degrades the radiation detection measurement

  15. Note: Measuring breakdown characteristics during the hot re-ignition of high intensity discharge lamps using high frequency alternating current voltage.

    Science.gov (United States)

    van den Bos, R A J M; Sobota, A; Manders, F; Kroesen, G M W

    2013-04-01

    To investigate the cold and hot re-ignition properties of High Intensity Discharge (HID) lamps in more detail an automated setup was designed in such a way that HID lamps of various sizes and under different background pressures can be tested. The HID lamps are ignited with a ramped sinusoidal voltage signal with frequencies between 60 and 220 kHz and with amplitude up to 7.5 kV. Some initial results of voltage and current measurements on a commercially available HID lamp during hot and cold re-ignition are presented.

  16. Current-voltage hysteresis and dielectric properties of PVA coated MWCNT film

    Science.gov (United States)

    Das, Amit Kumar; Meikap, Ajit Kumar

    2017-12-01

    In this work, we have prepared polyvinyl alcohol (PVA) coated multiwall carbon nanotube (MWCNT) film by an in situ chemical oxidative preparation technique. The thermogravimetric analysis clearly explains the thermal degradation of pure polymer and polymer nanocomposite film. We have studied the AC electrical transport properties and current-voltage (I-V) characteristic of PVA-MWCNT composites within the temperature range 300 ≤ T ≤ 423 K and frequency range 150 Hz ≤ f ≤ 2 MHz. It is observed that the dielectric constant of the composite film increases significantly. The frequency variation of AC conductivity follows the power law ( ωS ) and a sharp transition from small polaron tunneling to correlated barrier hopping model is found. The imaginary part of electric modulus shows non-Debye type asymmetric behaviour. The impedance spectroscopy shows the negative temperature coefficient of resistance of the composite film. Nyquist plot of the composite film at different temperatures is established from impedance measurement. The current-voltage characteristic (under ± 20 V) shows hysteresis behaviour and field dependent resistance. We simulate the experimentally observed current density-electric field data with the established theory.

  17. Current-voltage hysteresis and dielectric properties of PVA coated MWCNT film

    Science.gov (United States)

    Das, Amit Kumar; Meikap, Ajit Kumar

    2018-06-01

    In this work, we have prepared polyvinyl alcohol (PVA) coated multiwall carbon nanotube (MWCNT) film by an in situ chemical oxidative preparation technique. The thermogravimetric analysis clearly explains the thermal degradation of pure polymer and polymer nanocomposite film. We have studied the AC electrical transport properties and current-voltage (I-V) characteristic of PVA-MWCNT composites within the temperature range 300 ≤ T ≤ 423 K and frequency range 150 Hz ≤ f ≤ 2 MHz. It is observed that the dielectric constant of the composite film increases significantly. The frequency variation of AC conductivity follows the power law ( ωS ) and a sharp transition from small polaron tunneling to correlated barrier hopping model is found. The imaginary part of electric modulus shows non-Debye type asymmetric behaviour. The impedance spectroscopy shows the negative temperature coefficient of resistance of the composite film. Nyquist plot of the composite film at different temperatures is established from impedance measurement. The current-voltage characteristic (under ± 20 V) shows hysteresis behaviour and field dependent resistance. We simulate the experimentally observed current density-electric field data with the established theory.

  18. Angular-dependent I-V characteristics in borocarbide superconductor YNi2B2C

    International Nuclear Information System (INIS)

    Chu, R M; Chen, Q Y; Chu, W K

    2006-01-01

    We present angular-dependent current-voltage (I-V) measurements in borocarbide YNi 2 B 2 C single crystals near the vortex-glass irreversible line. External magnetic fields are applied along the angle θ with respect to the c-axis. The nonlinear I-V curves reveal scaling behaviour near the transition. Using the scaling analysis, the relevant critical exponents and vortex transition temperatures are determined for all orientations. The data agrees well with the vortex-glass (VG) model. No evidence was found that supports the existence of a Bose-glass (BG) type of transition

  19. An analytic current-voltage model for quasi-ballistic III-nitride high electron mobility transistors

    Science.gov (United States)

    Li, Kexin; Rakheja, Shaloo

    2018-05-01

    We present an analytic model to describe the DC current-voltage (I-V) relationship in scaled III-nitride high electron mobility transistors (HEMTs) in which transport within the channel is quasi-ballistic in nature. Following Landauer's transport theory and charge calculation based on two-dimensional electrostatics that incorporates negative momenta states from the drain terminal, an analytic expression for current as a function of terminal voltages is developed. The model interprets the non-linearity of access regions in non-self-aligned HEMTs. Effects of Joule heating with temperature-dependent thermal conductivity are incorporated in the model in a self-consistent manner. With a total of 26 input parameters, the analytic model offers reduced empiricism compared to existing GaN HEMT models. To verify the model, experimental I-V data of InAlN/GaN with InGaN back-barrier HEMTs with channel lengths of 42 and 105 nm are considered. Additionally, the model is validated against numerical I-V data obtained from DC hydrodynamic simulations of an unintentionally doped AlGaN-on-GaN HEMT with 50-nm gate length. The model is also verified against pulsed I-V measurements of a 150-nm T-gate GaN HEMT. Excellent agreement between the model and experimental and numerical results for output current, transconductance, and output conductance is demonstrated over a broad range of bias and temperature conditions.

  20. Depth-resolved ultra-violet spectroscopic photo current-voltage measurements for the analysis of AlGaN/GaN high electron mobility transistor epilayer deposited on Si

    International Nuclear Information System (INIS)

    Ozden, Burcu; Yang, Chungman; Tong, Fei; Khanal, Min P.; Mirkhani, Vahid; Sk, Mobbassar Hassan; Ahyi, Ayayi Claude; Park, Minseo

    2014-01-01

    We have demonstrated that the depth-dependent defect distribution of the deep level traps in the AlGaN/GaN high electron mobility transistor (HEMT) epi-structures can be analyzed by using the depth-resolved ultra-violet (UV) spectroscopic photo current-voltage (IV) (DR-UV-SPIV). It is of great importance to analyze deep level defects in the AlGaN/GaN HEMT structure, since it is recognized that deep level defects are the main source for causing current collapse phenomena leading to reduced device reliability. The AlGaN/GaN HEMT epi-layers were grown on a 6 in. Si wafer by metal-organic chemical vapor deposition. The DR-UV-SPIV measurement was performed using a monochromatized UV light illumination from a Xe lamp. The key strength of the DR-UV-SPIV is its ability to provide information on the depth-dependent electrically active defect distribution along the epi-layer growth direction. The DR-UV-SPIV data showed variations in the depth-dependent defect distribution across the wafer. As a result, rapid feedback on the depth-dependent electrical homogeneity of the electrically active defect distribution in the AlGaN/GaN HEMT epi-structure grown on a Si wafer with minimal sample preparation can be elucidated from the DR-UV-SPIV in combination with our previously demonstrated spectroscopic photo-IV measurement with the sub-bandgap excitation.

  1. Depth-resolved ultra-violet spectroscopic photo current-voltage measurements for the analysis of AlGaN/GaN high electron mobility transistor epilayer deposited on Si

    Energy Technology Data Exchange (ETDEWEB)

    Ozden, Burcu; Yang, Chungman; Tong, Fei; Khanal, Min P.; Mirkhani, Vahid; Sk, Mobbassar Hassan; Ahyi, Ayayi Claude; Park, Minseo, E-mail: park@physics.auburn.edu [Department of Physics, Auburn University, Auburn, Alabama 36849 (United States)

    2014-10-27

    We have demonstrated that the depth-dependent defect distribution of the deep level traps in the AlGaN/GaN high electron mobility transistor (HEMT) epi-structures can be analyzed by using the depth-resolved ultra-violet (UV) spectroscopic photo current-voltage (IV) (DR-UV-SPIV). It is of great importance to analyze deep level defects in the AlGaN/GaN HEMT structure, since it is recognized that deep level defects are the main source for causing current collapse phenomena leading to reduced device reliability. The AlGaN/GaN HEMT epi-layers were grown on a 6 in. Si wafer by metal-organic chemical vapor deposition. The DR-UV-SPIV measurement was performed using a monochromatized UV light illumination from a Xe lamp. The key strength of the DR-UV-SPIV is its ability to provide information on the depth-dependent electrically active defect distribution along the epi-layer growth direction. The DR-UV-SPIV data showed variations in the depth-dependent defect distribution across the wafer. As a result, rapid feedback on the depth-dependent electrical homogeneity of the electrically active defect distribution in the AlGaN/GaN HEMT epi-structure grown on a Si wafer with minimal sample preparation can be elucidated from the DR-UV-SPIV in combination with our previously demonstrated spectroscopic photo-IV measurement with the sub-bandgap excitation.

  2. Langmuir probe measurements in a time-fluctuating-highly ionized non-equilibrium cutting arc: Analysis of the electron retarding part of the time-averaged current-voltage characteristic of the probe

    International Nuclear Information System (INIS)

    Prevosto, L.; Mancinelli, B.; Kelly, H.

    2013-01-01

    This work describes the application of Langmuir probe diagnostics to the measurement of the electron temperature in a time-fluctuating-highly ionized, non-equilibrium cutting arc. The electron retarding part of the time-averaged current-voltage characteristic of the probe was analysed, assuming that the standard exponential expression describing the electron current to the probe in collision-free plasmas can be applied under the investigated conditions. A procedure is described which allows the determination of the errors introduced in time-averaged probe data due to small-amplitude plasma fluctuations. It was found that the experimental points can be gathered into two well defined groups allowing defining two quite different averaged electron temperature values. In the low-current region the averaged characteristic was not significantly disturbed by the fluctuations and can reliably be used to obtain the actual value of the averaged electron temperature. In particular, an averaged electron temperature of 0.98 ± 0.07 eV (= 11400 ± 800 K) was found for the central core of the arc (30 A) at 3.5 mm downstream from the nozzle exit. This average included not only a time-average over the time fluctuations but also a spatial-average along the probe collecting length. The fitting of the high-current region of the characteristic using such electron temperature value together with the corrections given by the fluctuation analysis showed a relevant departure of local thermal equilibrium in the arc core

  3. Langmuir probe measurements in a time-fluctuating-highly ionized non-equilibrium cutting arc: Analysis of the electron retarding part of the time-averaged current-voltage characteristic of the probe

    Energy Technology Data Exchange (ETDEWEB)

    Prevosto, L.; Mancinelli, B. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina); Kelly, H. [Grupo de Descargas Eléctricas, Departamento Ing. Electromecánica, Facultad Regional Venado Tuerto (UTN), Laprida 651, Venado Tuerto (2600) Santa Fe (Argentina); Instituto de Física del Plasma (CONICET), Departamento de Física, Facultad de Ciencias Exactas y Naturales (UBA) Ciudad Universitaria Pab. I, 1428 Buenos Aires (Argentina)

    2013-12-15

    This work describes the application of Langmuir probe diagnostics to the measurement of the electron temperature in a time-fluctuating-highly ionized, non-equilibrium cutting arc. The electron retarding part of the time-averaged current-voltage characteristic of the probe was analysed, assuming that the standard exponential expression describing the electron current to the probe in collision-free plasmas can be applied under the investigated conditions. A procedure is described which allows the determination of the errors introduced in time-averaged probe data due to small-amplitude plasma fluctuations. It was found that the experimental points can be gathered into two well defined groups allowing defining two quite different averaged electron temperature values. In the low-current region the averaged characteristic was not significantly disturbed by the fluctuations and can reliably be used to obtain the actual value of the averaged electron temperature. In particular, an averaged electron temperature of 0.98 ± 0.07 eV (= 11400 ± 800 K) was found for the central core of the arc (30 A) at 3.5 mm downstream from the nozzle exit. This average included not only a time-average over the time fluctuations but also a spatial-average along the probe collecting length. The fitting of the high-current region of the characteristic using such electron temperature value together with the corrections given by the fluctuation analysis showed a relevant departure of local thermal equilibrium in the arc core.

  4. Langmuir probe measurements in a time-fluctuating-highly ionized non-equilibrium cutting arc: analysis of the electron retarding part of the time-averaged current-voltage characteristic of the probe.

    Science.gov (United States)

    Prevosto, L; Kelly, H; Mancinelli, B

    2013-12-01

    This work describes the application of Langmuir probe diagnostics to the measurement of the electron temperature in a time-fluctuating-highly ionized, non-equilibrium cutting arc. The electron retarding part of the time-averaged current-voltage characteristic of the probe was analysed, assuming that the standard exponential expression describing the electron current to the probe in collision-free plasmas can be applied under the investigated conditions. A procedure is described which allows the determination of the errors introduced in time-averaged probe data due to small-amplitude plasma fluctuations. It was found that the experimental points can be gathered into two well defined groups allowing defining two quite different averaged electron temperature values. In the low-current region the averaged characteristic was not significantly disturbed by the fluctuations and can reliably be used to obtain the actual value of the averaged electron temperature. In particular, an averaged electron temperature of 0.98 ± 0.07 eV (= 11400 ± 800 K) was found for the central core of the arc (30 A) at 3.5 mm downstream from the nozzle exit. This average included not only a time-average over the time fluctuations but also a spatial-average along the probe collecting length. The fitting of the high-current region of the characteristic using such electron temperature value together with the corrections given by the fluctuation analysis showed a relevant departure of local thermal equilibrium in the arc core.

  5. Inhomogeneous barrier height effect on the current-voltage characteristics of an Au/n-InP Schottky diode

    Science.gov (United States)

    Zeghdar, Kamal; Dehimi, Lakhdar; Saadoune, Achour; Sengouga, Nouredine

    2015-12-01

    We report the current-voltage (I-V) characteristics of the Schottky diode (Au/n-InP) as a function of temperature. The SILVACO-TCAD numerical simulator is used to calculate the I-V characteristic in the temperature range of 280-400 K. This is to study the effect of temperature on the I-V curves and assess the main parameters that characterize the Schottky diode such as the ideality factor, the height of the barrier and the series resistance. The I-V characteristics are analyzed on the basis of standard thermionic emission (TE) theory and the inhomogeneous barrier heights (BHs) assuming a Gaussian distribution. It is shown that the ideality factor decreases while the barrier height increases with increasing temperature, on the basis of TE theory. Furthermore, the homogeneous BH value of approximately 0.524 eV for the device has been obtained from the linear relationship between the temperature-dependent experimentally effective BHs and ideality factors. The modified Richardson plot, according to the inhomogeneity of the BHs, has a good linearity over the temperature range. The evaluated Richardson constant A* was 10.32 A·cm-2·K-2, which is close to the theoretical value of 9.4 A·cm-2·K-2 for n-InP. The temperature dependence of the I-V characteristics of the Au/n-InP Schottky diode have been successfully explained on the basis of the thermionic emission (TE) mechanism with a Gaussian distribution of the Schottky barrier heights (SBHs). Simulated I-V characteristics are in good agreement with the measurements [Korucu D, Mammadov T S. J Optoelectronics Advanced Materials, 2012, 14: 41]. The barrier height obtained using Gaussian Schottky barrier distribution is 0.52 eV, which is about half the band gap of InP.

  6. Random instabilities of current-voltage curves of BSCCO-2223/Ag multifilamentary tapes in LN2 at 77 K

    CERN Document Server

    Usak, P

    2003-01-01

    The measurement of the current-voltage (I-V) characteristics of BSCCO-2223/Ag multifilamentary tapes in a silver matrix has been performed on short samples (of several centimetres) as well as on long tape (1 m), wound in the form of a helical one-layer coil. Measurements at 77 K and in zero external magnetic field have revealed good reproducibility of the I-V hysteresis in most runs. Nevertheless, strange irregularities have sometimes been observed in the I-V curve behaviour during current ramping up and down. Quasi-reproducible drops from the ascending hysteretic branch in the direction of the descending one have been measured at higher voltage levels (approx 1 mV cm sup - sup 1) on the curve measured on the helical coil. These have recently been explained by a sudden change in the heat transfer coefficient [1]. Rarely and non-reproducibly we have also observed these drops on short samples at E approx 1 x 10 sup - sup 2 V m sup - sup 1 , (and even under 1 x 10 sup - sup 3 V m sup - sup 1). The accidental dro...

  7. Tunneling effects in the current-voltage characteristics of high-efficiency GaAs solar cells

    Science.gov (United States)

    Kachare, R.; Anspaugh, B. E.; Garlick, G. F. J.

    1988-01-01

    Evidence is that tunneling via states in the forbidden gap is the dominant source of excess current in the dark current-voltage (I-V) characteristics of high-efficiency DMCVD grown Al(x)Ga(1-x)As/GaAs(x is equal to or greater than 0.85) solar cells. The dark forward and reverse I-V measurements were made on several solar cells, for the first time, at temperatures between 193 and 301 K. Low-voltage reverse-bias I-V data of a number of cells give a thermal activation energy for excess current of 0.026 + or - 0.005 eV, which corresponds to the carbon impurity in GaAs. However, other energy levels between 0.02 eV and 0.04 eV were observed in some cells which may correspond to impurity levels introduced by Cu, Si, Ge, or Cd. The forward-bias excess current is mainly due to carrier tunneling between localized levels created in the space-charge layer by impurities such as carbon, which are incorporated during the solar cell growth process. A model is suggested to explain the results.

  8. Fault identification in crystalline silicon PV modules by complementary analysis of the light and dark current-voltage characteristics

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Hacke, Peter

    2016-01-01

    This article proposes a fault identification method, based on the complementary analysis of the light and dark current-voltage (I-V) characteristics of the photovoltaic (PV) module, to distinguish between four important degradation modes that lead to power loss in PV modules: (a) degradation of t...

  9. Hysteretic current-voltage characteristics in RF-sputtered nanocrystalline TiO2 thin films

    International Nuclear Information System (INIS)

    Villafuerte, Manuel; Juarez, Gabriel; Heluani, Silvia P. de; Comedi, David

    2007-01-01

    We have measured the current-voltage characteristics at room temperature of a nanocrystalline TiO 2 thin film fabricated by reactive RF-sputtering deposition and sandwiched between ITO (indium-tin-oxide)-buffered glass substrate and an indium top electrode. The I-V characteristics are ohmic for low voltages and become non-linear, hysteretic and asymmetric as the voltage is increased. The system is shown to be well represented by two distinct resistance states in the non-ohmic region. Current transient evolutions were also measured for constant voltage excitations. The resistance is stable in time for voltages in the ohmic regime. In contrast, for voltages in the non-ohmic regime, the resistance has a small variation for a short period of time (order of tens seconds) and then increases with time. For those transients, long characteristic times (on the order of tens of minutes up to hours) were found. The behavior of the system is discussed on the basis of experimental results reported in the literature for similar systems and existing models for electric-field induced resistive switching

  10. Radiation effects on the current-voltage and capacitance-voltage characteristics of advanced p-n junction diodes surrounded by shallow trench isolation

    International Nuclear Information System (INIS)

    Poyai, A.; Simoen, E.; Claeys, C.; Hayama, K.; Kobayashi, K.; Ohyama, H.

    2002-01-01

    This paper investigates the impact of 20 MeV proton irradiation on the current-voltage (I-V) and capacitance-voltage (C-V) characteristics of different geometry n + -p-well junction diodes surrounded by shallow trench isolation and processed in a 0.18 μm CMOS technology. From I-V characteristics, a higher current damage coefficient was found for the bulk than for the peripheral component. The radiation-induced boron de-activation resulted in a lowering of the p-well doping, which has been derived from high-frequency C-V measurements. This was confirmed by deep level transient spectroscopy (DLTS) analysis, revealing the presence of interstitial boron related radiation defects. As will be demonstrated for the bulk leakage-current damage coefficient, the electric field enhanced generation rate of charge carriers and the radiation-induced boron de-activation should be accounted for properly

  11. Nonlinear current-voltage behavior in PZT thin films

    Energy Technology Data Exchange (ETDEWEB)

    Xiao, Mi; Zhang, Weikang; Zhang, Zebin; Li, Shida; Zhang, Ping; Lan, Kuibo [Tianjin University, School of Electrical and Information Engineering, Tianjin (China)

    2017-05-15

    In this paper, Pb(Zr{sub 0.52}Ti{sub 0.48})O{sub 3} (PZT) thin films were prepared by sol-gel synthesis and characterized by X-ray diffraction, field emission scanning electron microscopy and current-voltage measurements. Here, we demonstrate that in addition to the outstanding ferroelectric and dielectric properties, the PZT films also have remarkably nonlinear current-voltage characteristics. Considering the contact of semi-conductive grains in the PZT films, a double Schottky barrier (DSB) model may be responsible for such phenomena. The test results show that with the decrease of annealing temperature and the increase of the film thickness, the threshold voltages (V{sub th}) increase obviously. The maximum V{sub th} value of 60.95 V and the minimum value of 6.9 V in our experiments were obtained from the five-layered samples annealed at 600 C and the two-layered samples annealed at 700 C, respectively. As a result, PZT thin film may lead to efficient switching and sensing devices. (orig.)

  12. Evaluation of resting brain conditions measured by two different methods (i.v. and oral administration) with 18F-FDG-PET

    International Nuclear Information System (INIS)

    Masud, M.; Yamaguchi, Keiichiro; Rikimaru, Hisashi; Tashiro, Manabu; Ozaki, Kaoru; Watanuki, Shoichi; Miyake, Masayasu; Ido, Tatsuo; Itoh, Masatoshi

    2001-01-01

    Our aim was to evaluate regional differences between brain activity in two resting control conditions measured by 3D PET after administration of FDG through either the intravenous (i.v.) or the oral route. Ten healthy male volunteers engaged in the study as the i.v. group (mean age, 26±9.3 years, ±S.D.) who received FDG intravenously and another 10 volunteers as the oral group (mean age, 27.9±11.3 years, ±S.D.) who received FDG per os. A set of 3D-PET scans (emission and transmission scans) were performed in both groups. To explore possible functional differences between the brains of the two groups, the SPM-96 software was used for statistical analysis. The results revealed that glucose metabolism was significantly higher in the superior frontal gyrus, superior parietal lobule, lingual gyrus and left cerebellar hemisphere in the i.v. group than in the oral group. Metabolically active areas were found in the superior, middle and inferior temporal gyrus, parahippocampal gyrus, amygdaloid nucleus, pons and cerebellum in the oral group when compared with the i.v. group. These differences were presumably induced by differences between FDG kinetics and/or time-weighted behavioral effects in the two studies. This study suggests the need for extreme caution when selecting a pooled control population for designated activation studies. (author)

  13. Evaluation of resting brain conditions measured by two different methods (i.v. and oral administration) with {sup 18}F-FDG-PET

    Energy Technology Data Exchange (ETDEWEB)

    Masud, M.; Yamaguchi, Keiichiro; Rikimaru, Hisashi; Tashiro, Manabu; Ozaki, Kaoru; Watanuki, Shoichi; Miyake, Masayasu; Ido, Tatsuo; Itoh, Masatoshi [Tohoku Univ., Sendai (Japan). Cyclotron and Radioisotope Center

    2001-02-01

    Our aim was to evaluate regional differences between brain activity in two resting control conditions measured by 3D PET after administration of FDG through either the intravenous (i.v.) or the oral route. Ten healthy male volunteers engaged in the study as the i.v. group (mean age, 26{+-}9.3 years, {+-}S.D.) who received FDG intravenously and another 10 volunteers as the oral group (mean age, 27.9{+-}11.3 years, {+-}S.D.) who received FDG per os. A set of 3D-PET scans (emission and transmission scans) were performed in both groups. To explore possible functional differences between the brains of the two groups, the SPM-96 software was used for statistical analysis. The results revealed that glucose metabolism was significantly higher in the superior frontal gyrus, superior parietal lobule, lingual gyrus and left cerebellar hemisphere in the i.v. group than in the oral group. Metabolically active areas were found in the superior, middle and inferior temporal gyrus, parahippocampal gyrus, amygdaloid nucleus, pons and cerebellum in the oral group when compared with the i.v. group. These differences were presumably induced by differences between FDG kinetics and/or time-weighted behavioral effects in the two studies. This study suggests the need for extreme caution when selecting a pooled control population for designated activation studies. (author)

  14. Si and SiC Schottky diodes in smart power circuits: a comparative study by I-V-T and C-V measurements

    Energy Technology Data Exchange (ETDEWEB)

    Hadzi-Vukovic, J [Infineon Technologies, Siemensstrasse 2, 9500 Villach (Austria); Jevtic, M [Institute for Physics, Pregrevica 118, 11080 Zemun (Serbia and Montenegro); Rothleitner, H [Infineon Technologies, Siemensstrasse 2, 9500 Villach (Austria); Croce, P Del [Infineon Technologies, Siemensstrasse 2, 9500 Villach (Austria)

    2005-01-01

    In this paper we analyze a possibility of manufacturing and implementation of Schottky diodes in the smart power circuits. Three different Schottky diodes, in three different technologies, are realized in Si and SiC processes. The electrical characterizations with I-V-T and C-V measurements are done for all structures. It is shown that Si based Schottky diodes also are suitable to be integrated in the typical smart power circuits.

  15. Si and SiC Schottky diodes in smart power circuits: a comparative study by I-V-T and C-V measurements

    International Nuclear Information System (INIS)

    Hadzi-Vukovic, J; Jevtic, M; Rothleitner, H; Croce, P Del

    2005-01-01

    In this paper we analyze a possibility of manufacturing and implementation of Schottky diodes in the smart power circuits. Three different Schottky diodes, in three different technologies, are realized in Si and SiC processes. The electrical characterizations with I-V-T and C-V measurements are done for all structures. It is shown that Si based Schottky diodes also are suitable to be integrated in the typical smart power circuits

  16. Investigation of the double exponential in the current-voltage characteristics of silicon solar cells

    Science.gov (United States)

    Wolf, M.; Noel, G. T.; Stirn, R. J.

    1976-01-01

    A theoretical analysis is presented of certain peculiarities of the current-voltage characteristics of silicon solar cells, involving high values of the empirical constant A in the diode equation for a p-n junction. An attempt was made in a lab experiment to demonstrate that the saturation current which is associated with the exponential term qV/A2kT of the I-V characteristic, with A2 roughly equal to 2, originates in the space charge region and that it can be increased, as observed on ATS-1 cells, by the introduction of additional defects through low energy proton irradiation. It was shown that the proton irradiation introduces defects into the space charge region which give rise to a recombination current from this region, although the I-V characteristic is, in this case, dominated by an exponential term which has A = 1.

  17. Water Electrolysis at Different Current - Voltage Regimes

    International Nuclear Information System (INIS)

    Kleperis, J.; Blums, J.; Vanags, M.

    2007-01-01

    Full text: Electrochemical impedance and volt-amperic methods were used to compare an efficiency of water electrolysis for different materials and different electrode configurations. Two and three electrode measurements were made, using standard calomel reference electrode. Non-standard capacitative electrolysis was analyzed in special cell made from cylindrical steel electrodes. Volt-amperic measurements from - 15V to +15V DC didn't indicated the presence of oxidation - reduction reactions when distilled water was used as electrolyte. Impedance measurements showed unusual frequency behavior when the AC voltage increased till 0.5V. Different nickel and carbon electrodes (plate, porous and textile - type) were used to learn classical Faraday electrolysis in strong alkali solutions. Flying increase of current was indicator of the presence of electrolysis, and characteristic potential was used differ between materials accordingly they effectiveness for usage in an electrolyser device. (Aithors)

  18. Current-voltage characteristics of porous-silicon structures

    International Nuclear Information System (INIS)

    Diligenti, A.; Nannini, A.; Pennelli, G.; Pieri, F.; Fuso, F.; Allegrini, M.

    1996-01-01

    I-V DC characteristics have been measured on metal/porous-silicon structures. In particular, the measurements on metal/free-standing porous-silicon film/metal devices confirmed the result, already obtained, that the metal/porous-silicon interface plays a crucial role in the transport of any device. Four-contacts measurements on free-standing layers showed that the current linearly depends on the voltage and that the conduction process is thermally activated, the activation energy depending on the porous silicon film production parameters. Finally, annealing experiments performed in order to improve the conduction of rectifying contacts, are described

  19. Current-Voltage Characteristic of Nanosecond - Duration Relativistic Electron Beam

    Science.gov (United States)

    Andreev, Andrey

    2005-10-01

    The pulsed electron-beam accelerator SINUS-6 was used to measure current-voltage characteristic of nanosecond-duration thin annular relativistic electron beam accelerated in vacuum along axis of a smooth uniform metal tube immersed into strong axial magnetic field. Results of these measurements as well as results of computer simulations performed using 3D MAGIC code show that the electron-beam current dependence on the accelerating voltage at the front of the nanosecond-duration pulse is different from the analogical dependence at the flat part of the pulse. In the steady-state (flat) part of the pulse), the measured electron-beam current is close to Fedosov current [1], which is governed by the conservation law of an electron moment flow for any constant voltage. In the non steady-state part (front) of the pulse, the electron-beam current is higher that the appropriate, for a giving voltage, steady-state (Fedosov) current. [1] A. I. Fedosov, E. A. Litvinov, S. Ya. Belomytsev, and S. P. Bugaev, ``Characteristics of electron beam formed in diodes with magnetic insulation,'' Soviet Physics Journal (A translation of Izvestiya VUZ. Fizika), vol. 20, no. 10, October 1977 (April 20, 1978), pp.1367-1368.

  20. Current-voltage characteristics of bulk heterojunction organic solar cells: connection between light and dark curves

    Energy Technology Data Exchange (ETDEWEB)

    Boix, Pablo P.; Guerrero, Antonio; Garcia-Belmonte, Germa; Bisquert, Juan [Photovoltaic and Optoelectronic Devices Group, Departament de Fisica, Universitat Jaume I, ES-12071 Castello (Spain); Marchesi, Luis F. [Laboratorio Interdisciplinar de, Eletroquimica e Ceramica (LIEC), Universidade Federal de Sao Carlos (Brazil); Photovoltaic and Optoelectronic Devices Group, Departament de Fisica, Universitat Jaume I, ES-12071 Castello (Spain)

    2011-11-15

    A connection is established between recombination and series resistances extracted from impedance spectroscopy and current-voltage curves of polythiophene:fullerene organic solar cells. Recombination is shown to depend exclusively on the (Fermi level) voltage, which allows construction of the current-voltage characteristics in any required conditions based on a restricted set of measurements. The analysis highlights carrier recombination current as the determining mechanism of organic solar cell performance. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Current-voltage-temperature characteristics of DNA origami

    Energy Technology Data Exchange (ETDEWEB)

    Bellido, Edson P; Bobadilla, Alfredo D; Rangel, Norma L; Seminario, Jorge M [Department of Chemical Engineering, Texas A and M University, College Station, TX 77843 (United States); Zhong Hong; Norton, Michael L [Department of Chemistry, Marshall University, Huntington, WV 25755 (United States); Sinitskii, Alexander [Department of Chemistry, Rice University, Houston, TX 77005 (United States)

    2009-04-29

    The temperature dependences of the current-voltage characteristics of a sample of triangular DNA origami deposited in a 100 nm gap between platinum electrodes are measured using a probe station. Below 240 K, the sample shows high impedance, similar to that of the substrate. Near room temperature the current shows exponential behavior with respect to the inverse of temperature. Sweep times of 1 s do not yield a steady state; however sweep times of 450 s for the bias voltage secure a steady state. The thermionic emission and hopping conduction models yield similar barriers of {approx}0.7 eV at low voltages. For high voltages, the hopping conduction mechanism yields a barrier of 0.9 eV and the thermionic emission yields 1.1 eV. The experimental data set suggests that the dominant conduction mechanism is hopping in the range 280-320 K. The results are consistent with theoretical and experimental estimates of the barrier for related molecules.

  2. Current-voltage-temperature characteristics of DNA origami

    International Nuclear Information System (INIS)

    Bellido, Edson P; Bobadilla, Alfredo D; Rangel, Norma L; Seminario, Jorge M; Zhong Hong; Norton, Michael L; Sinitskii, Alexander

    2009-01-01

    The temperature dependences of the current-voltage characteristics of a sample of triangular DNA origami deposited in a 100 nm gap between platinum electrodes are measured using a probe station. Below 240 K, the sample shows high impedance, similar to that of the substrate. Near room temperature the current shows exponential behavior with respect to the inverse of temperature. Sweep times of 1 s do not yield a steady state; however sweep times of 450 s for the bias voltage secure a steady state. The thermionic emission and hopping conduction models yield similar barriers of ∼0.7 eV at low voltages. For high voltages, the hopping conduction mechanism yields a barrier of 0.9 eV and the thermionic emission yields 1.1 eV. The experimental data set suggests that the dominant conduction mechanism is hopping in the range 280-320 K. The results are consistent with theoretical and experimental estimates of the barrier for related molecules.

  3. Current-voltage model of LED light sources

    DEFF Research Database (Denmark)

    Beczkowski, Szymon; Munk-Nielsen, Stig

    2012-01-01

    Amplitude modulation is rarely used for dimming light-emitting diodes in polychromatic luminaires due to big color shifts caused by varying magnitude of LED driving current and nonlinear relationship between intensity of a diode and driving current. Current-voltage empirical model of light...

  4. I-V Characteristics of PtxCo1−x (x = 0.2, 0.5, and 0.7 Thin Films

    Directory of Open Access Journals (Sweden)

    M. Erkovan

    2013-01-01

    Full Text Available Three different chemical ratios of PtxCo1−x thin films were grown on p-type native oxide Si (100 by Magneto Sputtering System with cosputtering technique at 350°C temperature to investigate electrical prosperities. X-ray photoelectron spectroscopy analysis technique was used to specify chemical ratios of these films. The current-voltage (I-V measurements of metal-semiconductor (MS Schottky diodes were carried out at room temperature. From the I-V analysis of the samples, ideality factor (n, barrier height (ϕ, and contact resistance values were determined by using thermionic emission (TE theory. Some important parameters such as barrier height, ideality factor, and serial resistance were calculated from the I-V characteristics based on thermionic emission mechanism. The ideality factors of the samples were not much greater than unity, and the serial resistances of the samples were also very low.

  5. Current voltage characteristics of composite superconductors with high contact resistance

    International Nuclear Information System (INIS)

    Akhmetov, A.A.; Baev, V.P.

    1984-01-01

    An experimental study has been made of current-voltage characteristics of composite superconductors with contact resistance between superconducting filaments and normal metal with high electrical conductivity. It is shown that stable resistive states exist in such conductors over a wide range of currents. The presence of resistive states is interpreted in terms of the resistive domain concept. The minimum and maximum currents of resistive states are found to be dependent on the electrical resistance of normal metal and magnetic field. (author)

  6. Branching in current-voltage characteristics of intrinsic Josephson junctions

    International Nuclear Information System (INIS)

    Shukrinov, Yu M; Mahfouzi, F

    2007-01-01

    We study branching in the current-voltage characteristics of the intrinsic Josephson junctions of high-temperature superconductors in the framework of the capacitively coupled Josephson junction model with diffusion current. A system of dynamical equations for the gauge-invariant phase differences between superconducting layers for a stack of ten intrinsic junctions has been numerically solved. We have obtained a total branch structure in the current-voltage characteristics. We demonstrate the existence of a 'breakpoint region' on the current-voltage characteristics and explain it as a result of resonance between Josephson and plasma oscillations. The effect of the boundary conditions is investigated. The existence of two outermost branches and correspondingly two breakpoint regions for the periodic boundary conditions is shown. One branch, which is observed only at periodic boundary conditions, corresponds to the propagating of the plasma mode. The second one corresponds to the situation when the charge oscillations on the superconducting layers are absent, excluding the breakpoint. A time dependence of the charge oscillations at breakpoints is presented

  7. Analysis of current-voltage characteristics of Au/pentacene/fluorine polymer/indium zinc oxide diodes by electric-field-induced optical second-harmonic generation

    Energy Technology Data Exchange (ETDEWEB)

    Nishi, Shohei; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology, 2-12-1 S3-33, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2015-06-28

    By using electric-field-induced optical second-harmonic generation measurement coupled with the conventional current-voltage (I-V) measurement, we studied the carrier transport of organic double-layer diodes with a Au/pentacene/fluorine polymer (FP)/indium zinc oxide (IZO) structure. The rectifying I-V characteristics were converted into the I-E characteristics of the FP and pentacene layers. Results suggest a model in which Schottky-type electron injection from the IZO electrode to the FP layer governs the forward electrical conduction (V > 0), where the space charge electric field produced in the FP layer by accumulated holes at the pentacene/FP interface makes a significant contribution. On the other hand, Schottky-type injection by accumulated interface electrons from the pentacene layer to the FP layer governs the backward electrical conduction (V < 0). The electroluminescence generated from the pentacene layer in the region V > 0 verifies the electron transport across the FP layer, and supports the above suggested model.

  8. Analysis of current-voltage characteristics of Au/pentacene/fluorine polymer/indium zinc oxide diodes by electric-field-induced optical second-harmonic generation

    International Nuclear Information System (INIS)

    Nishi, Shohei; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2015-01-01

    By using electric-field-induced optical second-harmonic generation measurement coupled with the conventional current-voltage (I-V) measurement, we studied the carrier transport of organic double-layer diodes with a Au/pentacene/fluorine polymer (FP)/indium zinc oxide (IZO) structure. The rectifying I-V characteristics were converted into the I-E characteristics of the FP and pentacene layers. Results suggest a model in which Schottky-type electron injection from the IZO electrode to the FP layer governs the forward electrical conduction (V > 0), where the space charge electric field produced in the FP layer by accumulated holes at the pentacene/FP interface makes a significant contribution. On the other hand, Schottky-type injection by accumulated interface electrons from the pentacene layer to the FP layer governs the backward electrical conduction (V < 0). The electroluminescence generated from the pentacene layer in the region V > 0 verifies the electron transport across the FP layer, and supports the above suggested model

  9. Ab initio and empirical studies on the asymmetry of molecular current-voltage characteristics

    International Nuclear Information System (INIS)

    Hoft, R C; Armstrong, N; Ford, M J; Cortie, M B

    2007-01-01

    We perform theoretical calculations of the tunnelling current through various small organic molecules sandwiched between gold electrodes by using both a tunnel barrier model and an ab initio transport code. The height of the tunnelling barrier is taken to be the work function of gold as modified by the adsorbed molecule and calculated from an ab initio electronic structure code. The current-voltage characteristics of these molecules are compared. Asymmetry is introduced into the system in two ways: an asymmetric molecule and a gap between the molecule and the right electrode. The latter is a realistic situation in scanning probe experiments. The asymmetry is also realized in the tunnel barrier model by two distinct work functions on the left and right electrodes. Significant asymmetry is observed in the ab initio i(V) curves. The tunnel barrier i(V) curves show much less pronounced asymmetry. The relative sizes of the currents through the molecules are compared. In addition, the performance of the WKB approximation is compared to the results obtained from the exact Schroedinger solution to the tunnelling barrier problem

  10. Current-voltage curves for molecular junctions computed using all-electron basis sets

    International Nuclear Information System (INIS)

    Bauschlicher, Charles W.; Lawson, John W.

    2006-01-01

    We present current-voltage (I-V) curves computed using all-electron basis sets on the conducting molecule. The all-electron results are very similar to previous results obtained using effective core potentials (ECP). A hybrid integration scheme is used that keeps the all-electron calculations cost competitive with respect to the ECP calculations. By neglecting the coupling of states to the contacts below a fixed energy cutoff, the density matrix for the core electrons can be evaluated analytically. The full density matrix is formed by adding this core contribution to the valence part that is evaluated numerically. Expanding the definition of the core in the all-electron calculations significantly reduces the computational effort and, up to biases of about 2 V, the results are very similar to those obtained using more rigorous approaches. The convergence of the I-V curves and transmission coefficients with respect to basis set is discussed. The addition of diffuse functions is critical in approaching basis set completeness

  11. A dynamic Monte Carlo study of anomalous current voltage behaviour in organic solar cells

    International Nuclear Information System (INIS)

    Feron, K.; Fell, C. J.; Zhou, X.; Belcher, W. J.; Dastoor, P. C.

    2014-01-01

    We present a dynamic Monte Carlo (DMC) study of s-shaped current-voltage (I-V) behaviour in organic solar cells. This anomalous behaviour causes a substantial decrease in fill factor and thus power conversion efficiency. We show that this s-shaped behaviour is induced by charge traps that are located at the electrode interface rather than in the bulk of the active layer, and that the anomaly becomes more pronounced with increasing trap depth or density. Furthermore, the s-shape anomaly is correlated with interface recombination, but not bulk recombination, thus highlighting the importance of controlling the electrode interface. While thermal annealing is known to remove the s-shape anomaly, the reason has been not clear, since these treatments induce multiple simultaneous changes to the organic solar cell structure. The DMC modelling indicates that it is the removal of aluminium clusters at the electrode, which act as charge traps, that removes the anomalous I-V behaviour. Finally, this work shows that the s-shape becomes less pronounced with increasing electron-hole recombination rate; suggesting that efficient organic photovoltaic material systems are more susceptible to these electrode interface effects

  12. The Effect of Image Potential on the Current-Voltage Characteristics of a Ferritin-layer

    Directory of Open Access Journals (Sweden)

    Eunjung Bang

    2010-11-01

    Full Text Available Considering for the concept of power storage systems, such as those used to supply power to microelectronic devices, ferritins have aroused a lot of interests for applications in bioelectrochemical devices. And electron transfer rates from the proteins to electrode surface are key determinants of overall performance and efficiency of the ferritin-based devices. Here we have investigated the electron transport mechanism of ferritin layer which was immobilized on an Au electrode. The current-voltage (I-V curves are obtained by a conductive atomic force microscope (c-AFM as a function of contact area between AFM tip and the ferritin layer. In the low voltage region, I-V curves are affected by both Fowler-Nordheim tunneling and image force. On the other hand, the experimental results are consistent with a Simmons model in a high voltage region, indicating that, as the voltage increases, the image potential has a dominant effect on the electron transport mechanism. These results are attributed to the film-like character of the ferritin layer, which generates an image potential to lower the barrier height in proportion to the voltage increment.

  13. Current-voltage characteristics of C70 solid near Meyer-Neldel temperature

    Science.gov (United States)

    Onishi, Koichi; Sezaimaru, Kouki; Nakashima, Fumihiro; Sun, Yong; Kirimoto, Kenta; Sakaino, Masamichi; Kanemitsu, Shigeru

    2017-06-01

    The current-voltage characteristics of the C70 solid with hexagonal closed-packed structures were measured in the temperature range of 250-450 K. The current-voltage characteristics can be described as a temporary expedient by a cubic polynomial of the voltage, i = a v 3 + b v 2 + c v + d . Moreover, the Meyer-Neldel temperature of the C70 solid was confirmed to be 310 K, at which a linear relationship between the current and voltage was observed. Also, at temperatures below the Meyer-Neldel temperature, the current increases with increasing voltage. On the other hand, at temperatures above the Meyer-Neldel temperature a negative differential conductivity effect was observed at high voltage side. The negative differential conductivity was related to the electric field and temperature effects on the mobility of charge carrier, which involve two variations in the carrier concentration and the activation energy for carrier hopping transport.

  14. Effect of prewarming EDTA blood samples to 37°C on platelet count measured by Sysmex XT-2000iV in dogs, cats, and horses.

    Science.gov (United States)

    Williams, Tim L; Archer, Joy

    2016-09-01

    Pseudothrombocytopenia secondary to platelet clumping is a common cause of preanalytic error for platelet counts in dogs, cats, and horses. In human beings, it is suggested that prewarming blood samples to 37°C prior to hematology analysis will reduce platelet clumping. The purpose of the study was to evaluate the effect of prewarming EDTA blood samples to 37°C on measured platelet counts and other hematologic variables. The EDTA blood samples from dogs, cats and horses submitted to the clinical pathology laboratory at the University of Cambridge were included. Complete blood cell counts performed using a Sysmex XT-2000iV hematology analyzer were done on samples at room temperature (approximately 22°C) and following warming of the samples to 37°C in a water bath. The Wilcoxon signed rank test was used to compare hematologic variables, including platelet count, before and after sample warming to 37°C. Data are presented as median (25(th) , 75(th) percentile) increase. Blood samples from 39 dogs, 19 cats, and 10 horses were included. Sample warming to 37°C resulted in a statistically significant increase in platelet counts in dogs (11 [-2, 30] ×10(9) /L), cats (36 [14, 84] ×10(9) /L), and horses (42 [31, 79] ×10(9) /L). Sample warming did not significantly affect other hematologic variables. Prewarming EDTA blood samples to 37°C prior to hematologic analysis increased platelet counts overall in canine, feline, and equine blood, but did not abrogate platelet clumping and pseudothrombocytopenia fully in some cases. Furthermore, true pseudothrombocytopenia was not confirmed in these animals. © 2016 American Society for Veterinary Clinical Pathology.

  15. Parameter extraction from I-V characteristics of PV devices

    Energy Technology Data Exchange (ETDEWEB)

    Macabebe, Erees Queen B. [Department of Electronics, Computer and Communications Engineering, Ateneo de Manila University, Loyola Heights, Quezon City 1108 (Philippines); Department of Physics and Centre for Energy Research, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa); Sheppard, Charles J. [Department of Physics, University of Johannesburg, PO Box 524, Auckland Park 2006 (South Africa); Dyk, E. Ernest van [Department of Physics and Centre for Energy Research, Nelson Mandela Metropolitan University, PO Box 77000, Port Elizabeth 6031 (South Africa)

    2011-01-15

    Device parameters such as series and shunt resistances, saturation current and diode ideality factor influence the behaviour of the current-voltage (I-V) characteristics of solar cells and photovoltaic modules. It is necessary to determine these parameters since performance parameters are derived from the I-V curve and information provided by the device parameters are useful in analyzing performance losses. This contribution presents device parameters of CuIn(Se,S){sub 2}- and Cu(In,Ga)(Se,S){sub 2}-based solar cells, as well as, CuInSe{sub 2}, mono- and multicrystalline silicon modules determined using a parameter extraction routine that employs Particle Swarm Optimization. The device parameters of the CuIn(Se,S){sub 2}- and Cu(In,Ga)(Se,S){sub 2}-based solar cells show that the contribution of recombination mechanisms exhibited by high saturation current when coupled with the effects of parasitic resistances result in lower maximum power and conversion efficiency. Device parameters of photovoltaic modules extracted from I-V characteristics obtained at higher temperature show increased saturation current. The extracted values also reflect the adverse effect of temperature on parasitic resistances. The parameters extracted from I-V curves offer an understanding of the different mechanisms involved in the operation of the devices. The parameter extraction routine utilized in this study is a useful tool in determining the device parameters which reveal the mechanisms affecting device performance. (author)

  16. Current-voltage characteristics of carbon nanostructured field emitters in different power supply modes

    Science.gov (United States)

    Popov, E. O.; Kolosko, A. G.; Filippov, S. V.; Romanov, P. A.; Terukov, E. I.; Shchegolkov, A. V.; Tkachev, A. G.

    2017-12-01

    We received and compared the current-voltage characteristics of large-area field emitters based on nanocomposites with graphene and nanotubes. The characteristics were measured in two high voltage scanning modes: the "slow" and the "fast". Correlation between two types of hysteresis observed in these regimes was determined. Conditions for transition from "reverse" hysteresis to the "direct" one were experimentally defined. Analysis of the eight-shaped hysteresis was provided with calculation of the effective emission parameters. The phenomenological model of adsorption-desorption processes in the field emission system was proposed.

  17. Current-voltage relationship in the auroral particle acceleration region

    Directory of Open Access Journals (Sweden)

    M. Morooka

    2004-11-01

    Full Text Available The current-voltage relationship in the auroral particle acceleration region has been studied statistically by the Akebono (EXOS-D satellite in terms of the charge carriers of the upward field-aligned current. The Akebono satellite often observed field-aligned currents which were significantly larger than the model value predicted by Knight (1973. We compared the upward field-aligned current estimated by three different methods, and found that low-energy electrons often play an important role as additional current carriers, together with the high-energy primary electrons which are expected from Knight's relation. Such additional currents have been observed especially at high and middle altitudes of the particle acceleration region. Some particular features of electron distribution functions, such as "cylindrical distribution functions" and "electron conics", have often been observed coinciding with the additional currents. They indicated time variability of the particle acceleration region. Therefore, we have concluded that the low-energy electrons within the "forbidden" region of electron phase space in the stationary model often contribute to charge carriers of the current because of the rapid time variability of the particle acceleration region. "Cylindrical distribution functions" are expected to be found below the time-varying potential difference. We statistically examined the locations of "cylindrical distribution function", and found that their altitudes are related to the location where the additional currents have been observed. This result is consistent with the idea that the low-energy electrons can also carry significant current when the acceleration region changes in time.

  18. Observation of linear I-V curves on vertical GaAs nanowires with atomic force microscope

    Science.gov (United States)

    Geydt, P.; Alekseev, P. A.; Dunaevskiy, M.; Lähderanta, E.; Haggrén, T.; Kakko, J.-P.; Lipsanen, H.

    2015-12-01

    In this work we demonstrate the possibility of studying the current-voltage characteristics for single vertically standing semiconductor nanowires on standard AFM equipped by current measuring module in PeakForce Tapping mode. On the basis of research of eight different samples of p-doped GaAs nanowires grown on different GaAs substrates, peculiar electrical effects were revealed. It was found how covering of substrate surface by SiOx layer increases the current, as well as phosphorous passivation of the grown nanowires. Elimination of the Schottky barrier between golden cap and the top parts of nanowires was observed. It was additionally studied that charge accumulation on the shell of single nanowires affects its resistivity and causes the hysteresis loops on I-V curves.

  19. Electrical Characterization of Graphite/InP Schottky Diodes by I-V-T and C-V Methods

    Science.gov (United States)

    Tiagulskyi, Stanislav; Yatskiv, Roman; Grym, Jan

    2018-02-01

    A rectifying junction was prepared by casting a drop of colloidal graphite on the surface of an InP substrate. The electrophysical properties of graphite/InP junctions were investigated in a wide temperature range. Temperature-dependent I-V characteristics of the graphite/InP junctions are explained by the thermionic emission mechanism. The Schottky barrier height (SBH) and the ideality factor were found to be 0.9 eV and 1.47, respectively. The large value of the SBH and its weak temperature dependence are explained by lateral homogeneity of the junction, which is related to the structure of the graphite layer. The moderate disagreement between the current-voltage and capacitance-voltage measurements is attributed to the formation of interfacial native oxide film on the InP surface.

  20. On the current-voltage relationship in fluid theory

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    1999-01-01

    Full Text Available The kinetic theory of precipitating electrons with Maxwellian source plasma yields the well-known current-voltage relationship (CV-relationship; Knight formula, which can in most cases be accurately approximated by a reduced linear formula. Our question is whether it is possible to obtain this CV-relationship from fluid theory, and if so, to what extent it is physically equivalent with the more accurate kinetic counterpart. An answer to this question is necessary before trying to understand how one could combine time-dependent and transient phenomena such as Alfvénic waves with a slowly evolving background described by the CV-relationship. We first compute the fluid quantity profiles (density, pressure etc. along a flux tube based on kinetic theory solution. A parallel potential drop accumulates plasma (and pressure below it, which explains why the current is linearly proportional to the potential drop in the kinetic theory even though the velocity of the accelerated particles is only proportional to the square root of the accelerating voltage. Electron fluid theory reveals that the kinetic theory results can be reproduced, except for different numerical constants, if and only if the polytropic index γ is equal to three, corresponding to one-dimensional motion. The convective derivative term v·∇v provides the equivalent of the "mirror force" and is therefore important to include in a fluid theory trying to describe a CV-relationship. In one-fluid equations the parallel electric field, at least in its functional form, emerges self-consistently. We find that the electron density enhancement below the potential drop disappears because the magnetospheric ions would be unable to neutralize it, and a square root CV-relationship results, in disagreement with kinetic theory and observations. Also, the potential drop concentrates just above the ionosphere, which is at odds with observations as well. To resolve this puzzle, we show that considering

  1. On the current-voltage relationship in fluid theory

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    Full Text Available The kinetic theory of precipitating electrons with Maxwellian source plasma yields the well-known current-voltage relationship (CV-relationship; Knight formula, which can in most cases be accurately approximated by a reduced linear formula. Our question is whether it is possible to obtain this CV-relationship from fluid theory, and if so, to what extent it is physically equivalent with the more accurate kinetic counterpart. An answer to this question is necessary before trying to understand how one could combine time-dependent and transient phenomena such as Alfvénic waves with a slowly evolving background described by the CV-relationship. We first compute the fluid quantity profiles (density, pressure etc. along a flux tube based on kinetic theory solution. A parallel potential drop accumulates plasma (and pressure below it, which explains why the current is linearly proportional to the potential drop in the kinetic theory even though the velocity of the accelerated particles is only proportional to the square root of the accelerating voltage. Electron fluid theory reveals that the kinetic theory results can be reproduced, except for different numerical constants, if and only if the polytropic index γ is equal to three, corresponding to one-dimensional motion. The convective derivative term v·∇v provides the equivalent of the "mirror force" and is therefore important to include in a fluid theory trying to describe a CV-relationship. In one-fluid equations the parallel electric field, at least in its functional form, emerges self-consistently. We find that the electron density enhancement below the potential drop disappears because the magnetospheric ions would be unable to neutralize it, and a square root CV-relationship results, in disagreement with kinetic theory and observations. Also, the potential drop concentrates just above the ionosphere, which is at odds with observations as well. To resolve this puzzle, we show that considering

  2. Analysis of the current-voltage characteristics of polymer-based organic light-emitting diodes (OLEDs deposited by spin coating

    Directory of Open Access Journals (Sweden)

    Ricardo Vera

    2010-04-01

    Full Text Available Polymer-based organic light-emitting diodes (OLEDs with the structure ITO / PEDOT:PSS / MDMO-PPV / Metal were prepared by spincoating. It is known that electroluminescence of these devices is strongly dependent on the material used as cathode and on the depositionparameters of the polymer electroluminescent layer MDMO-PPV. Objective. In this work the effect of i the frequency of the spin coater(1000-8000 rpm, ii the concentration of the MDMO-PPV: Toluene solution, and iii the material used as cathode (Aluminium or Silveron the electrical response of the devices, was evaluated through current-voltage (I-V measurements. Materials and methods. PEDOT:PPSand MDMO-PPV organic layers were deposited by spin coating on ITO substrates, and the OLED structure was completed with cathodesof aluminium and silver. The electric response of the devices was evaluated based on the I-V characteristics. Results. Diodes prepared withthinner organic films allow higher currents at lower voltages; this can be achieved either by increasing the frequency of the spin coater orby using concentrations of MDMO-PPV: Toluene lower than 2% weight. A fit of the experimental data showed that the diodes have twocontributions to the current. The first one is attributed to parasitic currents between anode and cathode, and the other one is a parallel currentthrough the organic layer, in which the carrier injection mechanism is mediated by thermionic emission. Conclusions. The results of thefitting and the energy level alignment through the whole structure show that PPV-based OLEDs are unipolar devices, with current mainlyattributed to hole transport.

  3. Improvements in DC Current-Ioltage (I-V) Characteristics of n-GaN Schottky Diode using Metal Overlap Edge Termination

    International Nuclear Information System (INIS)

    Munir, T.; Aziz, A. A.; Abdullah, M. J.; Ain, M. F.

    2010-01-01

    Practical design of GaN Schottky diodes incorporating a field plate necessitates an understanding of how the addition of such plate affects the diode performance. In this paper, we investigated the effects on DC current-voltage (I-V) characteristics of n-GaN schottky diode by incorporating metal overlap edge termination. The thickness of the oxide film varies from 0.001 to 1 micron. Two-dimensional Atlas/Blaze simulations revealed that severe electric field crowding across the metal semiconductor contact will cause reliability concern and limit device breakdown voltage. DC current-voltage (I-V) measurements indicate that the forward currents are higher for thinner oxide film schottky diodes with metal overlap edge termination than those of unterminated schottky diodes. The forward current increased due to formation of an accumulation layer underneath the oxide layer. Extending the field plate to beyond periphery regions of schottky contact does not result in any significant increase in forward current. The new techniques of ramp oxide metal overlap edge termination have been implemented to increase the forward current of n-GaN schottky diode. In reverse bias, breakdown voltage increased with edge termination oxide up to a certain limit of oxide thickness.

  4. The effects of fabrication temperature on current-voltage characteristics and energy efficiencies of quantum dot sensitized ZnOH-GO hybrid solar cells

    International Nuclear Information System (INIS)

    Islam, S. M. Z.; Gayen, Taposh; Tint, Naing; Alfano, Robert; Shi, Lingyan; Seredych, Mykola; Bandosz, Teresa J.

    2014-01-01

    The effects of fabrication temperature are investigated on the performance of CdSe quantum dot (QD)-sensitized hybrid solar cells of the composite material of zinc (hydr)oxide (ZnOH-GO)with 2 wt. % graphite oxide. The current-voltage (I-V) and photo-current measurements show that higher fabrication temperatures yield greater photovoltaic power conversion efficiencies that essentially indicate more efficient solar cells. Two Photon Fluorescence images show the effects of temperature on the internal morphologies of the solar devices based on such materials. The CdSe-QD sensitized ZnOH-GO hybrid solar cells fabricated at 450 °C showing conversion of ∼10.60% under a tungsten lamp (12.1 mW/cm 2 ) are reported here, while using potassium iodide as an electrolyte. The output photocurrent, I (μA) with input power, P (mW/cm 2 ) is found to be superlinear, showing a relation of I = P n , where n = 1.4.

  5. On the Transmission Line Pulse Measurement Technique

    OpenAIRE

    X. Rodriguez; M. Eduardo; M. Harington

    2015-01-01

    Transmission Line Pulse is a short pulse (25ns to 150ns) measurement of the current-voltage (I/V) characteristics of the ESD protection built into an integrated circuit. The short TLP pulses are used to simulate the short ESD pulse threats and integrated circuit must tolerate without being damaged. In this work the fundamental principles of how the TLP pulse is generated and used to create I-V characteristic plots will be explored. The measurement will be then used to characterize the I-V cha...

  6. Exploring dark current voltage characteristics of micromorph silicon tandem cells with computer simulations

    NARCIS (Netherlands)

    Sturiale, A.; Li, H. B. T.; Rath, J.K.; Schropp, R.E.I.; Rubinelli, F.A.

    2009-01-01

    The transport mechanisms controlling the forward dark current-voltage characteristic of the silicon micromorph tandem solar cell were investigated with numerical modeling techniques. The dark current-voltage characteristics of the micromorph tandem structure at forward voltages show three regions:

  7. Simulation of forward dark current voltage characteristics of tandem solar cells

    International Nuclear Information System (INIS)

    Rubinelli, F.A.

    2012-01-01

    The transport mechanisms tailoring the shape of dark current–voltage characteristics of amorphous and microcrystalline silicon based tandem solar cell structures are explored with numerical simulations. Our input parameters were calibrated by fitting experimental current voltage curves of single and double junction structures measured under dark and illuminated conditions. At low and intermediate forward voltages the dark current–voltage characteristics show one or two regions with a current–voltage exponential dependence. The diode factor is unique in tandem cells with the same material in both intrinsic layers and two dissimilar diode factors are observed in tandem cells with different materials on the top and bottom intrinsic layers. In the exponential regions the current is controlled by recombination through gap states and by free carrier diffusion. At high forward voltages the current grows more slowly with the applied voltage. The current is influenced by the onset of electron space charge limited current (SCLC) in tandem cells where both intrinsic layers are of amorphous silicon and by series resistance of the bottom cell in tandem cells where both intrinsic layers are of microcrystalline silicon. In the micromorph cell the onset of SCLC becomes visible on the amorphous top sub-cell. The dark current also depends on the thermal generation of electron–hole (e–h) pairs present at the tunneling recombination junction. The highest dependence is observed in the tandem structure where both intrinsic layers are of microcrystalline silicon. The prediction of meaningless dark currents at low forward and reverse voltages by our code is discussed and one solution is given. - Highlights: ► Transport mechanisms shaping the dark current-voltage curves of tandem devices. ► The devices are amorphous and microcrystalline based tandem solar cells. ► Two regions with a current-voltage exponential dependence are observed. ► The tandem J-V diode factor is the

  8. Current-voltage characteristic of a resonant tunneling diode under electromagnetic radiation

    Directory of Open Access Journals (Sweden)

    N Hatefi Kargan

    2013-09-01

    Full Text Available  In this paper, current-voltage characteristic of a resonant tunneling diode under electromagnetic radiation has been calculated and compared with the results when there is no electromagnetic radiation. For calculating current -voltage characteristic, it is required to calculate the transmission coefficient of electrons from the well and barrier structures of this device. For calculating the transmission coefficient of electrons at the presence of electromagnetic radiation, Finite Difference Time Domain (FDTD method has been used and when there is no electromagnetic radiation Transfer Matrix Method (TMM and finite diffirence time domain method have been used. The results show that the presence of electromagnetic radiation causes resonant states other than principal resonant state (without presence of electromagnetic radiation to appear on the transmition coefficient curve where they are in distances from the principal peak and from each other. Also, the presence of electromagnetic radiation causes peaks other than principal peak to appear on the current-voltage characteristics of the device. Under electromagnetic radiation, the number of peaks on the current-voltage curve is smaller than the number of peaks on the current-voltage transmission coefficient. This is due to the fact that current-voltage curve is the result of integration on the energy of electrons, Thus, the sharper and low height peaks on the transmission coefficient do not appear on the current-voltage characteristic curve.

  9. Thermal contact resistance measurement of conduction cooled binary current lead joint block in cryocooler based self field I-V characterization facility

    Energy Technology Data Exchange (ETDEWEB)

    Kundu, Ananya, E-mail: ananya@ipr.res.in; Das, Subrat Kumar; Agarwal, Anees Bano Pooja; Pradhan, Subrata [Institute for Plasma Research, Bhat, Gandhinagar, Gujarat 382428 (India)

    2016-05-23

    In the present study thermal resistance of conduction cooled current lead joint block employing two different interfacial material namely AlN sheet and Kapton Film have been studied in the temperature range 5K-35K. In each case, the performance of different interlayer materials e.g. Indium foil for moderately pressurized contacts (contact pressure <1 MPa), and Apiezon N Grease, GE varnish for low pressurized contact (contact pressure <1 MPa) is studied. The performances of AlN joint with Indium foil and with Apeizon N Grease are studied and it is observed that the contact resistance reduces more with indium foil as compared to greased contact. The contact resistance measurements of Kapton film with Apiezon N grease and with GE varnish were also carried out in the same temperature range. A comparative study of AlN joint with Indium foil and Kapton with GE varnish as filler material is carried out to demonstrate better candidate material among Kapton and AlN for a particular filler material in the same temperature range.

  10. Observation of dark pulses in 10 nm thick YBCO nanostrips presenting hysteretic current voltage characteristics

    Science.gov (United States)

    Ejrnaes, M.; Parlato, L.; Arpaia, R.; Bauch, T.; Lombardi, F.; Cristiano, R.; Tafuri, F.; Pepe, G. P.

    2017-12-01

    We have fabricated several 10 nm thick and 65 nm wide YBa2Cu3O7-δ (YBCO) nanostrips. The nanostrips with the highest critical current densities are characterized by hysteretic current voltage characteristics (IVCs) with a direct bistable switch from the zero-voltage to the finite voltage state. The presence of hysteretic IVCs allowed the observation of dark pulses due to fluctuations phenomena. The key role of the bistable behavior is its ability to transform a small disturbance (e.g. an intrinsic fluctuation) into a measurable transient signal, i.e. a dark pulse. On the contrary, in devices characterized by lower critical current density values, the IVCs are non-hysteretic and dark pulses have not been observed. To investigate the physical origin of the dark pulses, we have measured the bias current dependence of the dark pulse rate: the observed exponential increase with the bias current is compatible with mechanisms based on thermal activation of magnetic vortices in the nanostrip. We believe that the successful amplification of small fluctuation events into measurable signals in nanostrips of ultrathin YBCO is a milestone for further investigation of YBCO nanostrips for superconducting nanostrip single photon detectors and other quantum detectors for operation at higher temperatures.

  11. Hole-transport limited S-shaped I-V curves in planar heterojunction organic photovoltaic cells

    Science.gov (United States)

    Zhang, Minlu; Wang, Hui; Tang, C. W.

    2011-11-01

    Current-voltage (I-V) characteristics of planar heterojunction organic photovoltaic cells based on N',N'-Di-[(1-naphthyl)-N',N'-diphenyl]-1,1'-biphenyl)-4,4'-diamine (NPB) and C60 are investigated. Through variation of the layer thickness and composition, specifically chemical doping NPB with MoOx, we show that the hole-transport limitation in the NPB layer is the determining factor in shaping the I-V characteristics of NPB/C60 cells.

  12. Analysis of the current-voltage characteristics lineshapes of resonant tunneling diodes

    International Nuclear Information System (INIS)

    Rivera, P.H.; Schulz, P.A.

    1996-01-01

    It is discussed the influence of a two dimensional electron gas at the emitter-barrier interface on the current-voltage characteristics of a Ga As-Al Ga As double-barrier quantum well resonant tunneling diode. This effect is characterized by the modification of the space charge distribution along the structure. Within the framework of a self-consistent calculation we analyse the current-voltage characteristics of the tunneling diodes. This analysis permits us to infer different tunneling ways, related to the formation of confined states in the emitter region, and their signatures in the current-voltage characteristics. We show that varying the spacer layer, together with barrier heights, changes drastically the current density-voltage characteristics lineshapes. We compare our results with a variety of current-voltage characteristics lineshapes. We compare our results with a variety of current-voltage characteristics reported in the literature. The general trend of experimental lineshapes can be reproduced and interpreted with our model. The possibility of tunneling paths is predicted for a range that has not yet been explored experimentally. (author). 12 refs., 4 figs

  13. Current-voltage characteristics of individual conducting polymer nanotubes and nanowires

    Institute of Scientific and Technical Information of China (English)

    Long Yun-ze; Yin Zhi-Hua; Li Meng-Meng; Gu Chang-Zhi; Duvail Jean-Luc; Jin Ai-zi; Wan Mei-xiang

    2009-01-01

    We report the current-voltage (Ⅰ-Ⅴ) characteristics of individual polypyrrole nanotubes and poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires in a temperature range from 300 K to 2 K. Considering the complex structures of such quasi-one-dimensional systems with an array of ordered conductive regions separated by disordered barriers, we use the extended fluctuation-induced tunneling (FIT) and thermal excitation model (Kaiser expression) to fit the temperature and electric-field dependent Ⅰ-Ⅴ curves. It is found that the Ⅰ-Ⅴ data measured at higher temperatures or higher voltages can be well fitted by the Kaiser expression. However, the low-temperature data around the zero bias clearly deviate from those obtained from this model. The deviation (or zero-bias conductance suppression)could be possibly ascribed to the occurrence of the Coulomb-gap in the density of states near the Femi level and/or the enhancement of electron-electron interaction resulting from nanosize effects, which have been revealed in the previous studies on low-temperature electronic transport in conducting polymer films, pellets and nanostructures. In addition,similar Ⅰ-Ⅴ characteristics and deviation are also observed in an isolated K0.27MnO2 nanowire.

  14. Spectroscopic, scanning laser OBIC, and I-V/QE characterizations of browned EVA solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Pern, F.J. [National Renewable Energy Lab., Golden, CO (United States); Eisgruber, I.L. [Materials Research Group, Inc., Wheat Ridge, CO (United States); Micheels, R.H. [Polestar Technologies, Inc., Needham Hts, MA (United States)

    1996-05-01

    The effects of ethylene-vinyl acetate (EVA) discoloration due to accelerated field or laboratory exposure on the encapsulated silicon (Si) solar cells or EVA/glass laminates were characterized quantitatively by using non-invasive, non-destructive ultraviolet-visible (UV-vis) spectrophotometry, spectrocolorimetry, spectrofluorometry, scanning laser OBIC (optical beam induced current) spectroscopy, and current-voltage (I-V) and quantum efficiency (QE) measurements. The results show that the yellowness index (YI) measured directly over the AR-coated solar cells under the glass superstrate increased from the range of -80 to -90 to the range of -20 to 15 as the EVA changed from clear to brown. The ratio of two fluorescence emission peak areas generally increased from 1.45 to 5.69 as browning increased, but dropped to 4.21 on a darker EVA. For a solar cell with brown EVA in the central region, small-area grating QE measurements and scanning laser OBIC analysis between the brown and clear EVA regions showed that the quantum efficiency loss at 633 nm was 42%-48% of the loss at 488 nm, due to a reduced decrease of transmittance in browned EVA at the longer wavelengths. The portion of the solar cell under the browned EVA showed a decrease of {approximately}36% in efficiency, as compared to the cell efficiency under clear EVA. Transmittance loss at 633 nm was 38% of the loss at 488 nm for a light yellow-brown EVA/glass laminate that showed a small increase of 10 in the yellowness index.

  15. Comment on: "Current-voltage characteristics and zero-resistance state in 2DEG"

    OpenAIRE

    Cheremisin, M. V.

    2003-01-01

    We demonstrate that N(S)-shape current-voltage characteristics proposed to explain zero-resistance state in Corbino(Hall bar) geometry 2DEG (cond-mat/0302063, cond-mat/0303530) cannot account essential features of radiation-induced magnetoresistance oscillations experiments.

  16. Module Five: Relationships of Current, Voltage, and Resistance; Basic Electricity and Electronics Individualized Learning System.

    Science.gov (United States)

    Bureau of Naval Personnel, Washington, DC.

    This module covers the relationships between current and voltage; resistance in a series circuit; how to determine the values of current, voltage, resistance, and power in resistive series circuits; the effects of source internal resistance; and an introduction to the troubleshooting of series circuits. This module is divided into five lessons:…

  17. Current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization

    International Nuclear Information System (INIS)

    Stoyanov, D G

    2007-01-01

    The balances of particles and charges in the volume of parallel-plane ionization chamber are considered. Differential equations describing the distribution of current densities in the chamber volume are obtained. As a result of the differential equations solution an analytical form of the current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization in the volume is obtained

  18. Current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization

    Energy Technology Data Exchange (ETDEWEB)

    Stoyanov, D G [Faculty of Engineering and Pedagogy in Sliven, Technical University of Sofia, 59, Bourgasko Shaussee Blvd, 8800 Sliven (Bulgaria)

    2007-08-15

    The balances of particles and charges in the volume of parallel-plane ionization chamber are considered. Differential equations describing the distribution of current densities in the chamber volume are obtained. As a result of the differential equations solution an analytical form of the current-voltage characteristic of parallel-plane ionization chamber with inhomogeneous ionization in the volume is obtained.

  19. Current-voltage relation for thin tunnel barriers: Parabolic barrier model

    DEFF Research Database (Denmark)

    Hansen, Kim; Brandbyge, Mads

    2004-01-01

    We derive a simple analytic result for the current-voltage curve for tunneling of electrons through a thin uniform insulating layer modeled by a parabolic barrier. Our model, which goes beyond the Wentzel–Kramers–Brillouin approximation, is applicable also in the limit of highly transparant...

  20. Bidirectional current-voltage converters based on magnetostrictive/piezoelectric composites

    NARCIS (Netherlands)

    Jia, Y.; Or, S.W.; Chan, H.L.W.; Jiao, J.; Luo, H.; Van der Zwaag, S.

    2009-01-01

    We report a power supply-free, bidirectional electric current-voltage converter based on a coil-wound laminated composite of magnetostrictive alloy and piezoelectric crystal. An electric current applied to the coil induces a magnetic field, resulting in an electric voltage from the composite due to

  1. Onset of chaos and dc current-voltage characteristics of rf-driven Josephson junctions in the low-frequency regime

    International Nuclear Information System (INIS)

    Chi, C.C.; Vanneste, C.

    1990-01-01

    A comprehensive picture of the dc current-voltage (I-V) characteristics of rf-driven Josephson junctions in the low-frequency regime is presented. The boundary of the low-frequency regime is roughly defined by the junction characteristic frequency for overdamped junctions, and by the inverse of the junction damping time for underdamped junctions. An adiabatic model valid for the low-frequency regime is used to describe the overall shapes of the I-V curves, which is in good agreement with both the numerical simulations and the experimental results. For underdamped junctions, the Shapiro steps are the prominent features on the I-V curves if the rf frequency is sufficiently below the boundary. As the rf frequency is increased towards the boundary, large negatively-going tails on top of the Shapiro steps are observed both experimentally and numerically. Numerical simulations using the resistively- and capacitively-shunted-junction model (RCSJ model) reveal that the negatively-going tail is a signature of the low-frequency boundary of the junction chaotic regime. With use of the adiabatic model and the existence of plasma oscillations for underdamped junctions, the onset of chaos and its effect on the Shapiro steps can be fully explained. The high-frequency limit of the adiabatic model and the chaotic behavior of the Josephson junctions beyond the low-frequency regime are also briefly discussed

  2. The effect of applied control strategy on the current-voltage correlation of a solid oxide fuel cell stack during dynamic operation

    Science.gov (United States)

    Szmyd, Janusz S.; Komatsu, Yosuke; Brus, Grzegorz; Ghigliazza, Francesco; Kimijima, Shinji; Ściążko, Anna

    2014-09-01

    This paper discusses the transient characteristics of the planar type SOFC cell stack, of which the standard output is 300 W. The transient response of the voltage to the manipulation of an electric current was investigated. The effects of the response and of the operating condition determined by the operating temperature of the stack were studied by mapping a current-voltage (I-V) correlation. The current-based fuel control (CBFC) was adopted for keeping the fuel utilization factor at constant while the value of the electric current was ramped at the constant rate. The present experimental study shows that the transient characteristics of the cell voltage are determined by primarily the operating temperature caused by the manipulation of the current. Particularly, the slope of the I-V curve and the overshoot found on the voltage was remarkably influenced by the operating temperature. The different values of the fuel utilization factor influence the height of the settled voltages. The CBFC has significance in determining the slope of the I-V characteristic, but the different values ofthe fuel utilization factor does not affect the slope as the operating temperature does. The CBFC essentially does not alter the amplitude of the overshoot on the voltage response, since this is dominated by the operating temperature and its change is caused by manipulating the current.

  3. The effect of applied control strategy on the current-voltage correlation of a solid oxide fuel cell stack during dynamic operation

    Directory of Open Access Journals (Sweden)

    Szmyd Janusz S.

    2014-09-01

    Full Text Available This paper discusses the transient characteristics of the planar type SOFC cell stack, of which the standard output is 300 W. The transient response of the voltage to the manipulation of an electric current was investigated. The effects of the response and of the operating condition determined by the operating temperature of the stack were studied by mapping a current-voltage (I-V correlation. The current-based fuel control (CBFC was adopted for keeping the fuel utilization factor at constant while the value of the electric current was ramped at the constant rate. The present experimental study shows that the transient characteristics of the cell voltage are determined by primarily the operating temperature caused by the manipulation of the current. Particularly, the slope of the I-V curve and the overshoot found on the voltage was remarkably influenced by the operating temperature. The different values of the fuel utilization factor influence the height of the settled voltages. The CBFC has significance in determining the slope of the I-V characteristic, but the different values ofthe fuel utilization factor does not affect the slope as the operating temperature does. The CBFC essentially does not alter the amplitude of the overshoot on the voltage response, since this is dominated by the operating temperature and its change is caused by manipulating the current.

  4. Study of current-voltage characteristics in PbTe(Ga) alloys at low temperatures

    International Nuclear Information System (INIS)

    Akimov, B.A.; Albul, A.V.; Bogdanov, E.V.

    1992-01-01

    Results of determining current-voltage characteristics in PbTe(Ga) monocrystals of n- and p-types of conductivity in strong electric fields E ≤ 2 x 10 3 V/Cm at 4.2-77 K are presented. It was established that at helium and nitrogen temperatures, the current-voltage characteristics of PbTe(Ga) alloys, high-ohmic state of which was realized in helium, differed qualitatively from ones, typical for unalloyed PbTe. The superlinear dependence, observed in the fields, beginning from E ≥ 1 V/cm, is explained in the framework of concepts of strong electric field effect on conductivity of impurity states

  5. Method of controlling illumination device based on current-voltage model

    DEFF Research Database (Denmark)

    2013-01-01

    The present invention relates to an illumination device comprising a number of LEDs, means for receiving an input signal, means for generating an activation signal for at least one of the LEDs based on the input signal. The illumination device comprises further means for obtaining the voltage...... and the colorimetric properties of said light emitted by LED. The present invention relates also to a method of controlling and a meted of calibrating such illumination device....... across and current through the LED and the means for generating the activation signal is adapted to generate the activating signal based on the voltage, the current and a current- voltage model related to LED. The current-voltage model defines a relationship between the current, the voltage...

  6. Illumination dependence of I-V and C-V characterization of Au/InSb/InP(1 0 0) Schottky structure

    International Nuclear Information System (INIS)

    Akkal, B.; Benamara, Z.; Bouiadjra, N. Bachir; Tizi, S.; Gruzza, B.

    2006-01-01

    The effects of surface preparation and illumination on electric parameters of Au/InSb/InP(100) Schottky diode were investigated, in the later diode InSb forms a fine restructuration layer allowing to block In atoms migration to surface. In order to study the electric characteristics under illumination, we make use of an He-Ne laser of 1 mW power and 632.8 nm wavelength. The current-voltage I(V G ), the capacitance-voltage C(V G ) measurements were plotted and analysed. The saturation current I s , the serial resistance R s and the mean ideality factor n are, respectively, equal to 2.03 x 10 -5 A, 85 Ω, 1.7 under dark and to 3.97 x 10 -5 A, 67 Ω, 1.59 under illumination. The analysis of I(V G ) and C(V G ) characteristics allows us to determine the mean interfacial state density N ss and the transmission coefficient θ n equal, respectively, to 4.33 x 10 12 eV -1 cm -2 , 4.08 x 10 -3 under dark and 3.79 x 10 12 eV -1 cm -2 and 5.65 x 10 -3 under illumination. The deep discrete donor levels presence in the semiconductor bulk under dark and under illumination are responsible for the non-linearity of the C -2 (V G ) characteristic

  7. A simple approximation for the current-voltage characteristics of high-power, relativistic diodes

    Energy Technology Data Exchange (ETDEWEB)

    Ekdahl, Carl, E-mail: cekdahl@lanl.gov [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2016-06-15

    A simple approximation for the current-voltage characteristics of a relativistic electron diode is presented. The approximation is accurate from non-relativistic through relativistic electron energies. Although it is empirically developed, it has many of the fundamental properties of the exact diode solutions. The approximation is simple enough to be remembered and worked on almost any pocket calculator, so it has proven to be quite useful on the laboratory floor.

  8. Hysteresis and negative differential resistance of the current-voltage characteristic of a water bridge

    Science.gov (United States)

    Oshurko, V. B.; Fedorov, A. N.; Ropyanoi, A. A.; Fedosov, M. V.

    2014-06-01

    It is found experimentally that the properties of nanoporous ion-exchange membranes (hysteresis of the current-voltage characteristic in the solution and negative differential resistance), which have been discussed in recent years, are not associated with the properties of the membrane. It is shown that these effects are also observed in a floating water bridge and in water-filled tubes and are apparently determined by the geometrical shape of the liquid conductor. The observed effects are explained qualitatively.

  9. Special features of the current-voltage characteristics of short superconducting bridges

    International Nuclear Information System (INIS)

    Zhilinskii, S.; Latyshev, Y.; Nad', F.

    1981-01-01

    A study was made of variable-thickness superconducting bridges made of tin and indium. The current-voltage characteristics were determined for these bridges as a function of their length and width. The characteristics exhibited a linear region as well as an inflection. The temperature of the appearance of such an inflection depended on the length of the bridge but was independent of the bridge material

  10. The dynamic current-voltage characteristic as a powerful tool to analyze fast phenomena in plasma

    International Nuclear Information System (INIS)

    Ivan, L. M.; Mihai-Plugaru, M.; Amarandei, G.; Aflori, M.; Dimitriu, D. G.

    2006-01-01

    The static current-voltage characteristic of an electrode immersed in plasma is obtained by slowly increasing and subsequently decreasing the potential on the electrode with respect to the plasma potential or the ground. This characteristic can give us important information about the phenomena that take place in front of the electrode. Current jumps can be evidenced which were often associated with an hysteresis effect, regions with S-type or N-type negative differential resistance, etc. The method is always used when we investigate the appearance of complex space charge configurations (CSCC) in front of an electrode immersed in plasma. However, to investigate the dynamics of such structures or other fast phenomena (like instabilities) which take place in plasma devices with frequencies of tenth, hundred kHz or more, complex investigation techniques must be used. One of the most efficient methods to investigate fast phenomena in plasma devices is the dynamic current-voltage characteristic. This is obtained by recording the time series of the current collected by the electrode when the voltage applied on it is very fast modified (most likely increased) by using a signal generator. In this way, very fast oscillations of the current can be recorded and new phenomena can be evidenced. We used this technique to study the phenomena which take place at the onset of electrostatic instabilities in Q-machine plasma, namely the potential relaxation instability (PRI) and the electrostatic ion-cyclotron instability (EICI). The obtained experimental results prove that the negative differential resistance region in the static current-voltage characteristic is the result of a nonlinear dynamics of a CSCC in form of a double layer (DL) which takes place just before the onset of the instabilities. In the case of the PRI we emphasized current jumps related with the DL appearance, which are not present in the static current-voltage characteristic at high plasma density. (authors)

  11. Effect of electric and magnetic fields on current-voltage characteristics of a lyotropic liquid crystal

    International Nuclear Information System (INIS)

    Minasyants, M.Kh.; Badalyan, G. G.; Shahinian, A. A.

    1997-01-01

    The effect of electric and magnetic fields on current-voltage characteristics is studied for the lamellar phase in the lyotropic liquid-crystal sodium pentadecylsulfonate (SPDS)-water and lecithin-water systems. It has been found that the current-voltage characteristics of both systems have hysteresis. In the case of ionogenic SPDS, the hysteresis is formed due to ion current caused by the spatial reorientation of domains consisting of parallel lamellar fragments; in the case of lecithin, whose molecules contain dipoles, the hysteresis is formed due to the spatial reorientation of domains caused by the interaction of the resultant dipole moment of the domains with the electric field. It is shown that the introduction into lamellae of cetylpyridine bromide, which has an intrinsic magnetic moment, changes the resultant magnetic moment of domains and, thus, also the hysteresis loop of the current-voltage characteristic. The systems studied show the 'memory' effect with respect to both the electric and magnetic fields. Field-induced processes of domain reorientation were recorded by the method of small-angle x-ray scattering

  12. Singularities of current-voltage characteristics of GaAs films fabricated by pulsed ions ablation

    International Nuclear Information System (INIS)

    Kabyshev, A.V.; Konusov, F.V.; Lozhnikov, S.N.; Remnev, G.E.; Saltymakov, M.S.

    2009-01-01

    A singularities and advantages of the optical, photoelectric and electrical properties of GaAs in comparison with other available materials for electronics, for example, silicon allow to manufacture on it base the devices having an advanced characteristics. The GaAs for electronics, obtained from the dense ablation plasma, possess some preferences as compared to material manufactured by traditional methods of vacuum deposition. The electrical characteristics of GaAs produced by chemical deposition were extensively studied. Purpose of this work is investigation the current-voltage characteristics of thin films of GaAs, deposited on polycrystalline corundum (polycor) from plasma forming the power ions bunch and determination of the thermal vacuum annealing effect on photoelectric and electrical properties of films. Peculiarities of optical, photoelectric and current-voltage characteristics of films obtained by ions ablation are determined by deposition conditions and resistance of initial target GaAs. The transitions between the states with low- and high conduction were revealed directly after deposition in films having the optical properties similar to amorphous materials and/or after annealing in films with properties similar to initial target GaAs. Behavior of current-voltage characteristics at vacuum annealing correlates with Schottky barrier height and photosensitivity and is accompanies of the transport mechanism change. The stable properties of films are formed at its dark conduction 10 -10 -10 -8 s and after annealing at T an =600-700 K. (authors)

  13. Low-temperature current-voltage characteristics of MIS Cu/n-GaAs and inhomogeneous Cu/n-GaAs Schottky diodes

    Energy Technology Data Exchange (ETDEWEB)

    Biber, M

    2003-01-01

    The current-voltage (I-V) characteristics of metal-insulating layer-semiconductor Cu/n-GaAs and inhomogeneous Cu/n-GaAs Schottky barrier diodes were determined in the temperature range 80-300 K. The evaluation of the experimental I-V data reveals a nonlinear increase of the zero-bias barrier height (qPHI{sub 0}) for the inhomogeneous Cu/n-GaAs Schottky barrier diodes and a linear increase of the zero-bias barrier height (qPHI{sub 0}) for Cu/n-GaAs Schottky barrier diodes with an interfacial layer. The ideality factor n decreases with increasing temperature for all diodes. Furthermore, the changes in PHI{sub 0} and n become quite significant below 150 K and the plot of ln(I{sub 0}/T{sup 2}) versus 1/T exhibits a non-linearity below 180 K for the inhomogeneous barrier diodes. Such behavior is attributed to barrier inhomogeneities by assuming a Gaussian distribution of barrier heights at the interface. The value of the Richardson constant was found to be 5.033 A/cm{sup 2} K{sup 2}, which is close to the theoretical value of 8.16 A/cm{sup 2} K{sup 2} used for the determination of the zero-bias barrier height.

  14. Phosphorene as a Superior Gas Sensor: Selective Adsorption and Distinct I-V Response.

    Science.gov (United States)

    Kou, Liangzhi; Frauenheim, Thomas; Chen, Changfeng

    2014-08-07

    Recent reports on the fabrication of phosphorene, that is, mono- or few-layer black phosphorus, have raised exciting prospects of an outstanding two-dimensional (2D) material that exhibits excellent properties for nanodevice applications. Here, we study by first-principles calculations the adsorption of CO, CO2, NH3, NO, and NO2 gas molecules on a monolayer phosphorene. Our results predict superior sensing performance of phosphorene that rivals or even surpasses that of other 2D materials such as graphene and MoS2. We determine the optimal adsorption positions of these molecules on the phosphorene and identify molecular doping, that is, charge transfer between the molecules and phosphorene, as the driving mechanism for the high adsorption strength. We further calculated the current-voltage (I-V) relation using the nonequilibrium Green's function (NEGF) formalism. The transport features show large (1-2 orders of magnitude) anisotropy along different (armchair or zigzag) directions, which is consistent with the anisotropic electronic band structure of phosphorene. Remarkably, the I-V relation exhibits distinct responses with a marked change of the I-V relation along either the armchair or the zigzag directions depending on the type of molecules. Such selectivity and sensitivity to adsorption makes phosphorene a superior gas sensor that promises wide-ranging applications.

  15. Impurity Deionization Effects on Surface Recombination DC Current-Voltage Characteristics in MOS Transistors

    International Nuclear Information System (INIS)

    Chen Zuhui; Jie Binbin; Sah Chihtang

    2010-01-01

    Impurity deionization on the direct-current current-voltage characteristics from electron-hole recombination (R-DCIV) at SiO 2 /Si interface traps in MOS transistors is analyzed using the steady-state Shockley-Read-Hall recombination kinetics and the Fermi distributions for electrons and holes. Insignificant distortion is observed over 90% of the bell-shaped R-DCIV curves centered at their peaks when impurity deionization is excluded in the theory. This is due to negligible impurity deionization because of the much lower electron and hole concentrations at the interface than the impurity concentration in the 90% range. (invited papers)

  16. Current-Voltage Characteristics of Nb2O5 nanoporous via light illumination

    Science.gov (United States)

    Samihah Khairir, Nur; Rani, Rozina Abdul; Fazlida Hanim Abdullah, Wan; Hafiz Mamat, Mohamad; Kadir, Rosmalini Abdul; Rusop, M.; Sabirin Zoolfakar, Ahmad

    2018-03-01

    This work discussed the effect of light on I-V characteristics of anodized niobium pentoxide (Nb2O5) which formed nanoporous structure film. The structure was synthesized by anodizing niobium foils in glycerol based solution with 10 wt% supplied by two different voltages, 5V and 10V. The anodized foils that contained Nb2O5 film were then annealed to obtain an orthorhombic phase for 30 minutes at 450°C. The metal contact used for I-V testing was platinum (Pt) and it was deposited using thermal evaporator at 30nm thickness. I-V tests were conducted under different condition; dark and illumination to study the effect of light on I-V characteristics of anodized nanoporous Nb2O5. Higher anodization voltage and longer anodization time resulted in higher pore dispersion and larger pore size causing the current to increase. The increase of conductivity in I-V behaviour of Nb2O5 device is also affected by the illumination test as higher light intensity caused space charge region width to increase, thus making it easier for electron transfer between energy band gap.

  17. Features of current-voltage characteristic of nonequilibrium trench MOS barrier Schottky diode

    Science.gov (United States)

    Mamedov, R. K.; Aslanova, A. R.

    2018-06-01

    The trench MOS barrier Schottky diodes (TMBS diode) under the influence of the voltage drop of the additional electric field (AEF) appearing in the near-contact region of the semiconductor are in a nonequilibrium state and their closed external circuit flows currents in the absence of an external voltage. When an external voltage is applied to the TMBS diode, the current transmission is described by the thermionic emission theory with a specific feature. Both forward and reverse I-V characteristics of the TMBS diode consist of two parts. In the initial first part of the forward I-V characteristic there are no forward currents, but reverse saturation currents flow, in its subsequent second part the currents increase exponentially with the voltage. In the initial first part of the reverse I-V characteristic, the currents increase in an abrupt way and in the subsequent second part the saturation currents flow under the action of the image force. The mathematical expressions for forward and reverse I-V characteristic of the TMBS diode and also narrow or nanostructure Schottky diode are proposed, which are in good agreement with the results of experimental and calculated I-V characteristics.

  18. Investigation of disorder and its effect on electrical transport in electrochemically doped polymer devices by current-voltage and impedance spectroscopy

    Science.gov (United States)

    Rahman Khan, Motiur; Anjaneyulu, P.; Koteswara Rao, K. S. R.; Menon, R.

    2017-03-01

    We report on the analysis of temperature-dependent current-voltage characteristics and impedance measurements of electrochemically doped poly(3-methylthiophene) devices at different doping levels. The extent of doping is carefully tailored such that only the bulk-limited transport mechanism prevails. A transition from exponentially distributed trap-limited transport to trap-free space-charge-limited current is observed in current-voltage conduction upon increasing the doping. The obtained trap densities (3.2  ×  1016 cm-3 and 8.6  ×  1015 cm-3) and trap energies (31.7 meV and 16.6 meV) for different devices signify the variation in disorder with doping, which is later supported by impedance measurements. Impedance-frequency data for various devices can not be explained using the parallel resistance-capacitance (RC) model in the equivalent circuit. However, this was established by incorporating a constant phase element Q (CPE) instead of the capacitance parameter. It should be emphasized that low doping devices in particular are best simulated with two CPE elements, while the data related to other devices are fitted well with a single CPE element. It is also observed from evaluated circuit parameters that the spatial inhomogeneity and disorder are the cause of variability in different samples, which has an excellent correlation with the temperature-dependent current-voltage characteristics.

  19. Current-voltage characteristic of a Josephson junction with randomly distributed Abrikosov vortices

    International Nuclear Information System (INIS)

    Fistul, M.V.; Giuliani, G.F.

    1997-01-01

    We have developed a theory of the current-voltage characteristic of a Josephson junction in the presence of randomly distributed, pinned misaligned Abrikosov vortices oriented perpendicularly to the junction plane. Under these conditions the Josephson phase difference var-phi acquires an interesting stochastic dependence on the position in the plane of the junction. In this situation it is possible to define an average critical current which is determined by the spatial correlations of this function. Due to the inhomogeneity, we find that for finite voltage bias the electromagnetic waves propagating in the junction display a broad spectrum of wavelengths. This is at variance with the situation encountered in homogeneous junctions. The amplitude of these modes is found to decrease as the bias is increased. We predict that the presence of these excitations is directly related to a remarkable feature in the current-voltage characteristic. The dependence of the position and the magnitude of this feature on the vortex concentration has been determined. copyright 1997 The American Physical Society

  20. Current-voltage curve of sodium channels and concentration dependence of sodium permeability in frog skin

    DEFF Research Database (Denmark)

    Fuchs, W; Larsen, Erik Hviid; Lindemann, B

    1977-01-01

    1. The inward facing membranes of in vitro frog skin epithelium were depolarized with solutions of high K concentration. The electrical properties of the epithelium are then expected to be governed by the outward facing, Na-selective membrane.2. In this state, the transepithelial voltage (V...... was recorded. This procedure was repeated after blocking the Na channels with amiloride to obtain the current-voltage curve of transmembrane and paracellular shunt pathways. The current-voltage curve of the Na channels was computed by subtracting the shunt current from the total current.4. The instantaneous I...... of the inward facing membranes but reflects the true behaviour of P(Na).6. The steady-state P(Na) at a given (Na)(o) is smaller than the transient P(Na) observed right after a stepwise increase of (Na)(o) to this value. The time constant of P(Na)-relaxation is in the order of seconds.7. In conclusion, Na...

  1. Influence of coupling parameter on current-voltage characteristics of intrinsic Josephson junctions in high-T c superconductors

    International Nuclear Information System (INIS)

    Shukrinov, Yu.M.; Mahfouzi, F.

    2006-01-01

    We study the current-voltage characteristics of intrinsic Josephson junctions in high-T c superconductors by numerical calculations and in framework of capacitively coupled Josephson junctions model we obtain the total number of branches. The influence of the coupling parameter α on the current-voltage characteristics at fixed parameter β (β 2 1/β c , where β c is McCumber parameter) and the influence of α on β-dependence of the current-voltage characteristics are investigated. We obtain the α-dependence of the branch's slopes and branch's endpoints. The presented results show new features of the coupling effect on the scheme of hysteresis jumps in current-voltage characteristics of intrinsic Josephson junctions in high-T c superconductors

  2. Effect of localized states on the current-voltage characteristics of metal-semiconductor contacts with thin interfacial layer

    Science.gov (United States)

    Chattopadhyay, P.

    1994-10-01

    The role of discrete localized states on the current-voltage characteristics of metal-semiconductor contact is examined. It is seen that, because of these localized states, the logarithmic current vs voltage characteristics become nonlinear. Such nonlinearity is found sensitive to the temperature, and the energy and density of the localized states. The predicted temperature dependence of barrier height and the current-voltage characteristics are in agreement with the experimental results of Aboelfotoh [ Phys. Rev. B39, 5070 (1989)].

  3. Current-voltage characteristics of the semiconductor nanowires under the metal-semiconductor-metal structure

    Science.gov (United States)

    Wen, Jing; Zhang, Xitian; Gao, Hong; Wang, Mingjiao

    2013-12-01

    We present a method to calculate the I-V characteristics of semiconductor nanowires under the metal-semiconductor-metal (MSM) structure. The carrier concentration as an important parameter is introduced into the expression of the current. The subband structure of the nanowire has been considered for associating it with the position of the Fermi level and circumventing the uncertainties of the contact areas in the contacts. The tunneling and thermionic emission currents in the two Schottky barriers at the two metal-semiconductor contacts are discussed. We find that the two barriers have different influences on the I-V characteristics of the MSM structure, one of which under the forward bias plays the role of threshold voltage if its barrier height is large and the applied voltage is small, and the other under the reverse bias controls the shapes of I-V curves. Our calculations show that the shapes of the I-V curves for the MSM structure are mainly determined by the barrier heights of the contacts and the carrier concentration. The nearly identical I-V characteristics can be obtained by using different values of the barrier heights and carrier concentration, which means that the contact type conversion can be ascribed not only to the changes of the barrier heights but also that of the carrier concentration. We also discuss the mechanisms of the ohmic-Schottky conversions and clarify the ambiguity in the literature. The possibility about the variation of the carrier concentration under the applied fields has been confirmed by experimental results.

  4. Current-Voltage Characteristics of DC Discharge in Micro Gas Jet Injected into Vacuum Environment

    International Nuclear Information System (INIS)

    Matra, K; Furuta, H; Hatta, A

    2013-01-01

    A current-voltage characteristic of direct current (DC) gas discharge operated in a micro gas jet injected into a secondary electron microscope (SEM) chamber is presented. Ar gas was injected through a 30 μm orifice gas nozzle (OGN) and was evacuated by an additional pump to keep the high vacuum environment. Gas discharges were ignited between the OGN as anode and a counter electrode of Si wafer. The discharge was self-pulsating in most of the cases while it was stable at lower pressure, larger gap length, and larger time averaged current. The self-pulsating discharge was oscillated by the RC circuit consisting of a stray capacitor and a large ballast resistor. The real time plots of voltage and current during the pulsating was investigated using a discharge model.

  5. Theoretical Current-Voltage Curve in Low-Pressure Cesium Diode for Electron-Rich Emission

    Science.gov (United States)

    Coldstein, C. M.

    1964-01-01

    Although considerable interest has been shown in the space-charge analysis of low-pressure (collisionless case) thermionic diodes, there is a conspicuous lack in the presentation of results in a way that allows direct comparison with experiment. The current-voltage curve of this report was, therefore, computed for a typical case within the realm of experimental interest. The model employed in this computation is shown in Fig. 1 and is defined by the limiting potential distributions [curves (a) and (b)]. Curve (a) represents the potential V as a monotonic function of position with a slope of zero at the anode; curve (b) is similarly monotonic with a slope of zero at the cathode. It is assumed that by a continuous variation of the anode voltage, the potential distributions vary continuously from one limiting form to the other. Although solutions for infinitely spaced electrodes show that spatically oscillatory potential distributions may exist, they have been neglected in this computation.

  6. CURRENT-VOLTAGE CURVES FOR TREATING EFFLUENT CONTAINING HEDP: DETERMINATION OF THE LIMITING CURRENT

    Directory of Open Access Journals (Sweden)

    T. Scarazzato

    2015-12-01

    Full Text Available Abstract Membrane separation techniques have been explored for treating industrial effluents to allow water reuse and component recovery. In an electrodialysis system, concentration polarization causes undesirable alterations in the ionic transportation mechanism. The graphic construction of the current voltage curve is proposed for establishing the value of the limiting current density applied to the cell. The aim of this work was to determine the limiting current density in an electrodialysis bench stack, the function of which was the treatment of an electroplating effluent containing HEDP. For this, a system with five compartments was used with a working solution simulating the rinse waters of HEDP-based baths. The results demonstrated correlation between the regions defined by theory and the experimental data.

  7. Calculation of current-voltage characteristics of electron-capture detectors

    International Nuclear Information System (INIS)

    Hinneburg, D.; Grosse, H.J.; Leonhardt, J.; Popp, P.

    1983-01-01

    Starting from the law of conservation of charge a stationary one-dimensional non-linear differential equation system is derived, which is applied to the direct-current mode of an electron-capture detector with parallel electrode plates. The theory takes into account space-charge, recombination, and inhomogeneous ionization and it deals with three kinds of charge carriers with different mobilities (positive and negative ions, electrons). Terms due to diffusion and gas-flow losses are excluded. The equations so constructed were programmed to get a means of calculating the charge and field distributions and the current-voltage characteristics as functions of various parameters of the detectors, the attaching gas and the ionization. For two cases the results are given. (author)

  8. Nonlinear current-voltage characteristics of WO3-x nano-/micro-rods

    Science.gov (United States)

    Shen, Zhenguang; Peng, Zhijian; Zhao, Zengying; Fu, Xiuli

    2018-04-01

    A series of crystalline tungsten oxide nano-/micro-rods with different compositions of WO3, WO2.90, W19O55 (WO2.89) and W18O49 (WO2.72) but identical morphology feature were first prepared. Then, various nanoscaled electrical devices were fabricated from them by micro-fabrication through a focused ion beam technique. Interestingly, the devices from the oxygen-deficient WO3-x display significantly nonlinear current-voltage characteristics. The calculated nonlinear coefficients of the WO2.90, WO2.83, and WO2.72 varistors are 2.52, 3.32 and 4.91, respectively. The breakdown voltage of the WO2.90, WO2.83, and WO2.72 varistors are 1.93, 1.28 and 0.93 V, respectively. Such WO3-x nano-varistors might be promising for low-voltage electrical/electronic devices.

  9. Autowaves in an active two-wire line with exponential current-voltage characteristics

    International Nuclear Information System (INIS)

    Zhuravlev, V. M.

    2006-01-01

    Nonlinear wave processes in two-wire lines containing an active element with an exponential current-voltage characteristic (CVC) similar to that of a p-n junction are investigated. These lines are models of systems that are encountered in various physical and biological applications, such as biological membranes and semiconductor devices. It is shown that such systems may operate in different modes each of which has different dispersion and dissipation properties and, as a consequence, is described by autowave processes of different types. The behavior of a system in all basic modes is analyzed. For each mode, exact solutions to relevant equations are found and their differential conservation laws and intrinsic symmetries are investigated. One of common properties of such equations is the presence of a special superposition principle that describes the discrete structure of excitations in a line that consist of individual elementary excitations. It is shown that autopulses may be generated in such systems

  10. Current-Voltage Characteristics of the Composites Based on Epoxy Resin and Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    Iwona Pełech

    2015-01-01

    Full Text Available Polymer composites based on epoxy resin were prepared. Multiwalled carbon nanotubes synthesized on iron-cobalt catalyst were applied as a filler in a polymer matrix. Chlorine or hydroxyl groups were incorporated on the carbon nanotubes surface via chlorination or chlorination followed by hydroxylation. The effect of functionalized carbon nanotubes on the epoxy resin matrix is discussed in terms of the state of CNTs dispersion in composites as well as electrical properties. For the obtained materials current-voltage characteristics were determined. They had a nonlinear character and were well described by an exponential-type equation. For all the obtained materials the percolation threshold occurred at a concentration of about 1 wt%. At a higher filler concentration >2 wt%, better conductivity was demonstrated by polymer composites with raw carbon nanotubes. At a lower filler concentration <2 wt%, higher values of electrical conductivity were obtained for polymer composites with modified carbon nanotubes.

  11. Magnetic field cycling effect on the non-linear current-voltage characteristics and magnetic field induced negative differential resistance in α-Fe1.64Ga0.36O3 oxide

    Science.gov (United States)

    Bhowmik, R. N.; Vijayasri, G.

    2015-06-01

    We have studied current-voltage (I-V) characteristics of α-Fe1.64Ga0.36O3, a typical canted ferromagnetic semiconductor. The sample showed a transformation of the I-V curves from linear to non-linear character with the increase of bias voltage. The I-V curves showed irreversible features with hysteresis loop and bi-stable electronic states for up and down modes of voltage sweep. We report positive magnetoresistance and magnetic field induced negative differential resistance as the first time observed phenomena in metal doped hematite system. The magnitudes of critical voltage at which I-V curve showed peak and corresponding peak current are affected by magnetic field cycling. The shift of the peak voltage with magnetic field showed a step-wise jump between two discrete voltage levels with least gap (ΔVP) 0.345(± 0.001) V. The magnetic spin dependent electronic charge transport in this new class of magnetic semiconductor opens a wide scope for tuning large electroresistance (˜500-700%), magnetoresistance (70-135 %) and charge-spin dependent conductivity under suitable control of electric and magnetic fields. The electric and magnetic field controlled charge-spin transport is interesting for applications of the magnetic materials in spintronics, e.g., magnetic sensor, memory devices and digital switching.

  12. Magnetic field cycling effect on the non-linear current-voltage characteristics and magnetic field induced negative differential resistance in α-Fe{sub 1.64}Ga{sub 0.36}O{sub 3} oxide

    Energy Technology Data Exchange (ETDEWEB)

    Bhowmik, R. N., E-mail: rnbhowmik.phy@pondiuni.edu.in; Vijayasri, G. [Department of Physics, Pondicherry University, R.Venkataraman Nagar, Kalapet, Puducherry - 605 014 (India)

    2015-06-15

    We have studied current-voltage (I-V) characteristics of α-Fe{sub 1.64}Ga{sub 0.36}O{sub 3}, a typical canted ferromagnetic semiconductor. The sample showed a transformation of the I-V curves from linear to non-linear character with the increase of bias voltage. The I-V curves showed irreversible features with hysteresis loop and bi-stable electronic states for up and down modes of voltage sweep. We report positive magnetoresistance and magnetic field induced negative differential resistance as the first time observed phenomena in metal doped hematite system. The magnitudes of critical voltage at which I-V curve showed peak and corresponding peak current are affected by magnetic field cycling. The shift of the peak voltage with magnetic field showed a step-wise jump between two discrete voltage levels with least gap (ΔV{sub P}) 0.345(± 0.001) V. The magnetic spin dependent electronic charge transport in this new class of magnetic semiconductor opens a wide scope for tuning large electroresistance (∼500-700%), magnetoresistance (70-135 %) and charge-spin dependent conductivity under suitable control of electric and magnetic fields. The electric and magnetic field controlled charge-spin transport is interesting for applications of the magnetic materials in spintronics, e.g., magnetic sensor, memory devices and digital switching.

  13. Magnetic field cycling effect on the non-linear current-voltage characteristics and magnetic field induced negative differential resistance in α-Fe1.64Ga0.36O3 oxide

    Directory of Open Access Journals (Sweden)

    R. N. Bhowmik

    2015-06-01

    Full Text Available We have studied current-voltage (I-V characteristics of α-Fe1.64Ga0.36O3, a typical canted ferromagnetic semiconductor. The sample showed a transformation of the I-V curves from linear to non-linear character with the increase of bias voltage. The I-V curves showed irreversible features with hysteresis loop and bi-stable electronic states for up and down modes of voltage sweep. We report positive magnetoresistance and magnetic field induced negative differential resistance as the first time observed phenomena in metal doped hematite system. The magnitudes of critical voltage at which I-V curve showed peak and corresponding peak current are affected by magnetic field cycling. The shift of the peak voltage with magnetic field showed a step-wise jump between two discrete voltage levels with least gap (ΔVP 0.345(± 0.001 V. The magnetic spin dependent electronic charge transport in this new class of magnetic semiconductor opens a wide scope for tuning large electroresistance (∼500-700%, magnetoresistance (70-135 % and charge-spin dependent conductivity under suitable control of electric and magnetic fields. The electric and magnetic field controlled charge-spin transport is interesting for applications of the magnetic materials in spintronics, e.g., magnetic sensor, memory devices and digital switching.

  14. Current-voltage characteristics of a tunnel junction with resonant centers

    International Nuclear Information System (INIS)

    Ivanov, T.; Valtchinov, V.

    1994-05-01

    We calculated the I-V characteristics of a tunnel junction containing impurities in the barrier. We consider the indirect resonant tunneling involving the impurities. The Coulomb repulsion energy E c between two electrons with opposite spins simultaneously residing on the impurity is introduced by an Anderson Hamiltonian. At low temperatures T is much less than E c the I-V characteristics is linear in V both for V c and for V>E c and changes slope at V=E c . This behaviour reflects the energy spectrum of the impurity electrons - the finite value of the charging energy E c . At T ∼ E c the junction reveals an ohmic-like behaviour as a result of the smearing out of the charging effects by the thermal fluctuations. (author). 10 refs, 2 figs

  15. Electronic Structure and I- V Characteristics of InSe Nanoribbons

    Science.gov (United States)

    Yao, A.-Long; Wang, Xue-Feng; Liu, Yu-Shen; Sun, Ya-Na

    2018-04-01

    We have studied the electronic structure and the current-voltage ( I-V) characteristics of one-dimensional InSe nanoribbons using the density functional theory combined with the nonequilibrium Green's function method. Nanoribbons having bare or H-passivated edges of types zigzag (Z), Klein (K), and armchair (A) are taken into account. Edge states are found to play an important role in determining their electronic properties. Edges Z and K are usually metallic in wide nanoribbons as well as their hydrogenated counterparts. Transition from semiconductor to metal is observed in hydrogenated nanoribbons HZZH as their width increases, due to the strong width dependence of energy difference between left and right edge states. Nevertheless, electronic structures of other nanoribbons vary with the width in a very limited scale. The I-V characteristics of bare nanoribbons ZZ and KK show strong negative differential resistance, due to spatial mismatch of wave functions in energy bands around the Fermi energy. Spin polarization in these nanoribbons is also predicted. In contrast, bare nanoribbons AA and their hydrogenated counterparts HAAH are semiconductors. The band gaps of nanoribbons AA (HAAH) are narrower (wider) than that of two-dimensional InSe monolayer and increase (decrease) with the nanoribbon width.

  16. Temperature dependent current-voltage characteristics of Au/n-Si Schottky barrier diodes and the effect of transition metal oxides as an interface layer

    Science.gov (United States)

    Mahato, Somnath; Puigdollers, Joaquim

    2018-02-01

    Temperature dependent current-voltage (I‒V) characteristics of Au/n-type silicon (n-Si) Schottky barrier diodes have been investigated. Three transition metal oxides (TMO) are used as an interface layer between gold and silicon. The basic Schottky diode parameters such as ideality factor (n), barrier height (ϕb 0) and series resistance (Rs) are calculated and successfully explained by the thermionic emission (TE) theory. It has been found that ideality factor decreased and barrier height increased with increased of temperature. The conventional Richardson plot of ln(I0/T2) vs. 1000/T is determined the activation energy (Ea) and Richardson constant (A*). Whereas value of 'A*' is much smaller than the known theoretical value of n-type Si. The temperature dependent I-V characteristics obtained the mean value of barrier height (ϕb 0 bar) and standard deviation (σs) from the linear plot of ϕap vs. 1000/T. From the modified Richardson plot of ln(I0/T2) ˗ (qσ)2/2(kT)2 vs. 1000/T gives Richardson constant and homogeneous barrier height of Schottky diodes. Main observation in this present work is the barrier height and ideality factor shows a considerable change but the series resistance value exhibits negligible change due to TMO as an interface layer.

  17. A uniform laminar air plasma plume with large volume excited by an alternating current voltage

    Science.gov (United States)

    Li, Xuechen; Bao, Wenting; Chu, Jingdi; Zhang, Panpan; Jia, Pengying

    2015-12-01

    Using a plasma jet composed of two needle electrodes, a laminar plasma plume with large volume is generated in air through an alternating current voltage excitation. Based on high-speed photography, a train of filaments is observed to propagate periodically away from their birth place along the gas flow. The laminar plume is in fact a temporal superposition of the arched filament train. The filament consists of a negative glow near the real time cathode, a positive column near the real time anode, and a Faraday dark space between them. It has been found that the propagation velocity of the filament increases with increasing the gas flow rate. Furthermore, the filament lifetime tends to follow a normal distribution (Gaussian distribution). The most probable lifetime decreases with increasing the gas flow rate or decreasing the averaged peak voltage. Results also indicate that the real time peak current decreases and the real time peak voltage increases with the propagation of the filament along the gas flow. The voltage-current curve indicates that, in every discharge cycle, the filament evolves from a Townsend discharge to a glow one and then the discharge quenches. Characteristic regions including a negative glow, a Faraday dark space, and a positive column can be discerned from the discharge filament. Furthermore, the plasma parameters such as the electron density, the vibrational temperature and the gas temperature are investigated based on the optical spectrum emitted from the laminar plume.

  18. Current-voltage characteristics of a superconducting slab under a superimposed small AC magnetic field

    International Nuclear Information System (INIS)

    Matsushita, Teruo; Yamafuji, Kaoru; Sakamoto, Nobuyoshi.

    1977-01-01

    In case of applying superconductors to electric machinery or high intensity field magnets for fusion reactors, the superconductors are generally expected to be sensible to small field fluctuation besides DC magnetic field. The behavior of superconductors in DC magnetic field superimposed with small AC magnetic field has been investigated often experimentally, and the result has been obtained that the critical current at which DC flow voltage begins to appear extremely decreased or disappeared. Some theoretical investigations have been carried out on this phenomenon so far, however, their application has been limited to the region where frequency is sufficiently low or which is close to the critical magnetic field. Purpose of this report is to deal with the phenomenon in more unified way by analyzing the behavior of magnetic flux lines in a superconductor under a superimposed small AC field using the criticalstate model including viscous force. In order to solve the fundamental equation in this report, first the solution has been obtained in the quasi-static state neglecting viscous force, then about the cases that current density J is not more than Jc and J is larger than Jc, concerning the deviation from the quasi-static limit by employing successive approximation. Current-voltage characteristics have been determined by utilizing the above results. This method seems to be most promising at present except the case of extremely high frequency. (Wakatsuki, Y.)

  19. Transport systems of Ventricaria ventricosa: I/V analysis of both membranes in series as a function of [K(+)](o).

    Science.gov (United States)

    Beilby, M J; Bisson, M A

    1999-09-01

    The current-voltage (I/V) profiles of Ventricaria (formerly Valonia) membranes were measured at a range of external potassium concentrations, [K(+)](o), from 0.1 to 100 mm. The conductance-voltage (G/V) characteristics were computed to facilitate better resolution of the profile change with time after exposure to different [K(+)](o). The resistance-voltage (R/V) characteristics were computed to attempt resolution of plasmalemma and tonoplast. Four basic electrophysiological stages emerged: (1) Uniform low resistance between -60 and +60 mV after the cell impalement. (2) High resistance between +50 and +150 for [K(+)](o) from 0.1 to 1.0 mm and hypotonic media. (3) High resistance between -150 and -20 mV for [K(+)](o) of 10 mm (close to natural seawater) and hypertonic media. (4) High resistance between -150 and +170 mV at [K(+)](o) of 100 mm. The changes between these states were slow, requiring minutes to hours and sometimes exhibiting spontaneous oscillations of the membrane p.d. (potential difference). Our analysis of the I/V data supports a previous hypothesis, that Ventricaria tonoplast is the more resistive membrane containing a pump, which transports K(+) into the vacuole to regulate turgor. We associate state (1) with the plasmalemma conductance being dominant and the K(+) pump at the tonoplast short-circuited probably by a K(+) channel, state (2) with the K(+) pump "off" or short-circuited at p.d.s more negative than +50 mV, state (3) with the K(+) pump "on, " and state (4) with the pump dominant, but affected by high K(+). A model for the Ventricaria membrane system is proposed.

  20. Transport current ac losses and current-voltage curves of multifilamentary Bi-2223/Ag tape with artificial defects

    International Nuclear Information System (INIS)

    Polak, M.; Jansak, L.

    2000-01-01

    We experimentally studied the effects of a single artificial defect and a linear array of artificial defects on I-V curves, critical currents and transport current ac losses of 55 filament untwisted Bi-2223/Ag tapes. The artificial defect was a small hole drilled into the tape. The reduction in the critical current measured on a 1 cm long section due to one hole of diameter 0.9 mm was 33% and that due to a linear array of seven similar holes was 62%. The slopes of the I-V curves, n, measured in this section were 33, 16 and 5.8 in the original sample, in the sample with one defect and the sample with seven defects, respectively. Both I c and the slope reduction were smaller if the distance between the potential taps was increased. The transport current ac losses at 50 Hz and I rms = 10 A in the sample with one defect measured in a 1 cm long section were practically the same as those in the original sample (4.1x10 -4 W m -1 ), but they increased by 83% in the sample with a linear array of seven defects. The measured increase in losses per unit length was the smaller, the larger the distance between the potential taps. A comparison between the measured and calculated losses revealed that a formal application of the Norris equations for loss calculations in samples with local defects leads to an overestimation of the ac losses. A procedure for the calculation of transport current losses in samples with local defects based on the Norris model is proposed and verified. (author)

  1. Temperature and Magnetic Field Driven Modifications in the I-V Features of Gold-DNA-Gold Structure

    Directory of Open Access Journals (Sweden)

    Nadia Mahmoudi Khatir

    2014-10-01

    Full Text Available The fabrication of Metal-DNA-Metal (MDM structure-based high sensitivity sensors from DNA micro-and nanoarray strands is a key issue in their development. The tunable semiconducting response of DNA in the presence of external electromagnetic and thermal fields is a gift for molecular electronics. The impact of temperatures (25–55 °C and magnetic fields (0–1200 mT on the current-voltage (I-V features of Au-DNA-Au (GDG structures with an optimum gap of 10 μm is reported. The I-V characteristics acquired in the presence and absence of magnetic fields demonstrated the semiconducting diode nature of DNA in GDG structures with high temperature sensitivity. The saturation current in the absence of magnetic field was found to increase sharply with the increase of temperature up to 45 °C and decrease rapidly thereafter. This increase was attributed to the temperature-assisted conversion of double bonds into single bond in DNA structures. Furthermore, the potential barrier height and Richardson constant for all the structures increased steadily with the increase of external magnetic field irrespective of temperature variations. Our observation on magnetic field and temperature sensitivity of I-V response in GDG sandwiches may contribute towards the development of DNA-based magnetic sensors.

  2. Temperature dependent I-V characteristics of an Au/n-GaAs Schottky diode analyzed using Tung’s model

    Science.gov (United States)

    Korucu, Demet; Turut, Abdulmecit; Efeoglu, Hasan

    2013-04-01

    The current-voltage (I-V) characteristics of Au/n-GaAs contacts prepared with photolithography technique have been measured in the temperature range of 80-320 K. The ideality factor and barrier height (BH) values have remained almost unchanged between 1.04 and 1.10 and at a value of about 0.79 eV at temperatures above 200 K, respectively. Therefore, the ideality factor values near unity say that the experimental I-V data are almost independent of the sample temperature, that is, contacts have shown excellent Schottky diode behavior above 200 K. An abnormal decrease in the experimental BH Φb and an increase in the ideality factor with a decrease in temperature have been observed below 200 K. This behavior has been attributed to the barrier inhomogeneity by assuming a Gaussian distribution of nanometer-sized patches with low BH at the metal-semiconductor interface. The barrier inhomogeneity assumption is also confirmed by the linear relationship between the BH and the ideality factor. According to Tung’s barrier inhomogeneity model, it has been seen that the value of σT=7.41×10-5 cm2/3 V1/3from ideality factor versus (kT)-1 curve is in close agreement with σT=7.95×10-5 cm2/3 V1/3 value from the Φeff versus (2kT)-1 curve in the range of 80-200 K. The modified Richardson ln(J0/T2)-(qσT)2(Vb/η)2/3/[2(kT)2] versus (kT)-1 plot, from Tung’s Model, has given a Richardson constant value of 8.47 A cm-2 K-2which is in very close agreement with the known value of 8.16 A cm-2 K-2 for n-type GaAs; considering the effective patch area which is significantly lower than the entire geometric area of the Schottky contact, in temperature range of 80-200 K. Thus, it has been concluded that the use of Tung’s lateral inhomogeneity model is more appropriate to interpret the temperature-dependent I-V characteristics in the Schottky contacts.

  3. A Contribution To The Development And Analysis Of A Combined Current-Voltage Instrument Transformer By Using Modern CAD Methods

    International Nuclear Information System (INIS)

    Chundeva-Blajer, Marija M.

    2004-01-01

    The principle aim and task of the thesis is the analysis and development of 20 kV combined current-voltage instrument transformer (CCVIT) by using modern CAD techniques. CCVIT is a complex electromagnetic system comprising of four windings and two magnetic cores in one insulation housing for simultaneous transformation of high voltages and currents to measurable signal values by standard instruments. The analytical design methods can be applied on simple electromagnetic configurations, which is not the case with the CCVIT. There is mutual electromagnetic influence between the voltage measurement core (VMC) and the current measurement core (CMC). After the analytical CCVIT design had been done, exact determination of its metrological characteristics has been accomplished by using the numerical finite element method implemented in the FEM-3D program package. The FEM-3D calculation is made in 19 cross-sectional layers of the z-axis of the CCVIT three-dimensional domain. By FEM-3D application the three-dimensional CCVIT magnetic field distribution is derived. This is the basis for calculation of the initial metrological characteristics of the CCVIT (VMC is accuracy class 3 and CMC is accuracy class 1). By using the stochastic optimization technique based on genetic algorithm the CCVIT optimal design is achieved. The objective function is the minimum of the metrological parameters (VIM voltage error and CMC current error). There are I I independent input variables during the optimization process by which the optimal project is derived. The optimal project is adapted for realization of a prototype and the optimized project is derived. Full comparative analysis of the metrological and the electromagnetic characteristics of the three projects is accomplished. By application of the program package MATLAB/SIMULINK the CCVIT transient phenomena is analyzed for different regimes in the three design projects. In the Instrument Transformer Factory of EMO A. D.-Ohrid a CCVIT

  4. Wavelengths and energy levels of I V and I VI

    International Nuclear Information System (INIS)

    Kaufman, V.; Sugar, J.; Joshi, Y.N.

    1988-01-01

    The spectra of iodine were photographed in the 139--1500-Aat;O region on various spectrographs. Earlier analyses of I V and I VI were revised and extended. For I V 26 lines were classified, and for I VI 35 lines were classified. Ionization energies have been estimated to be 415 510 atm≅ 300 cm -1 (51.52 atm≅ 0.04 eV) and 599 800 atm≅ 3 000 cm -1 (74.37 atm≅ 0.37 eV) for I V and I VI, respectively

  5. Electrical interface characteristics (I-V), optical time of flight measurements, and the x-ray (20 keV) signal response of amorphous-selenium/crystalline-silicon heterojunction structures

    Science.gov (United States)

    Hunter, David M.; Ho, Chu An; Belev, George; De Crescenzo, Giovanni; Kasap, Safa O.; Yaffe, Martin J.

    2011-03-01

    We have investigated the dark current, optical TOF (time of flight) properties, and the X-ray response of amorphousselenium (a-Se)/crystalline-silicon (c-Si) heterostructures for application in digital radiography. The structures have been studied to determine if an x-ray generated electron signal, created in an a-Se layer, could be directly transferred to a c-Si based readout device such as a back-thinned CCD (charge coupled device). A simple first order band-theory of the structure indicates that x-ray generated electrons should transfer from the a-Se to the c-Si, while hole transfer from p-doped c-Si to the a-Se should be blocked, permitting a low dark signal as required. The structures we have tested have a thin metal bias electrode on the x-ray facing side of the a-Se which is deposited on the c-Si substrate. The heterostructures made with pure a-Se deposited on epitaxial p-doped (5×10 14 cm-3) c-Si exhibited very low dark current of 15 pA cm-2 at a negative bias field of 10 V μm-1 applied to the a-Se. The optical TOF (time of flight) measurements show that the applied bias drops almost entirely across the a-Se layer and that the a-Se hole and electron mobilities are within the range of commonly accepted values. The x-ray signal measurements demonstrate the structure has the expected x-ray quantum efficiency. We have made a back-thinned CCD coated with a-Se and although most areas of the device show a poor x-ray response, it does contain small regions which do work properly with the expected x-ray sensitivity. Improved understanding of the a-Se/c-Si interface and preparation methods should lead to properly functioning devices.

  6. Local current-voltage behaviors of preferentially and randomly textured Cu(In,Ga)Se2 thin films investigated by conductive atomic force microscopy

    International Nuclear Information System (INIS)

    Shin, R.H.; Jo, W.; Kim, D.W.; Yun, Jae Ho; Ahn, S.

    2011-01-01

    Electrical transport properties on polycrystalline Cu(In,Ga)Se 2 (CIGS) (Ga/(In+Ga) ∼35%) thin films were examined by conductive atomic force microscopy. The CIGS thin films with a (112) preferential or random texture were deposited on Mo-coated glass substrates. Triangular pyramidal grain growths were observed in the CIGS thin films preferentially textured to the (112) planes. Current maps of the CIGS surface were acquired with a zero or non-zero external voltage bias. The contrast of the images on the grain boundaries and intragrains displayed the conduction path in the materials. Local current-voltage measurements were performed to evaluate the charge conduction properties of the CIGS thin films. (orig.)

  7. Local current-voltage behaviors of preferentially and randomly textured Cu(In,Ga)Se{sub 2} thin films investigated by conductive atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Shin, R.H.; Jo, W. [Ewha Womans University, Department of Physics, Seoul (Korea, Republic of); Kim, D.W. [Ewha Womans University, Department of Physics, Seoul (Korea, Republic of); Ewha Womans University, Department of Chemistry and Nanosciences, Seoul (Korea, Republic of); Yun, Jae Ho; Ahn, S. [Korea Institute of Energy Research, Daejeon (Korea, Republic of)

    2011-09-15

    Electrical transport properties on polycrystalline Cu(In,Ga)Se{sub 2} (CIGS) (Ga/(In+Ga) {approx}35%) thin films were examined by conductive atomic force microscopy. The CIGS thin films with a (112) preferential or random texture were deposited on Mo-coated glass substrates. Triangular pyramidal grain growths were observed in the CIGS thin films preferentially textured to the (112) planes. Current maps of the CIGS surface were acquired with a zero or non-zero external voltage bias. The contrast of the images on the grain boundaries and intragrains displayed the conduction path in the materials. Local current-voltage measurements were performed to evaluate the charge conduction properties of the CIGS thin films. (orig.)

  8. Effect of temperature on current voltage characteristics in ZnO/CdS/CuGaSe2 single crystal solar cells

    International Nuclear Information System (INIS)

    Saad, M.; Kassis, A.

    2005-03-01

    Current voltage characteristics of Zn O/CdS/CuGaSe 2 single crystal solar cells, which have gone through repetitive annealing treatment and have been measured at different values of temperature and illumination intensity, were analyzed using the two-diode equation. The analysis revealed that current transport in these cells is governed by two competing transport mechanisms relating strongly to interface states and that both mechanisms are thermally and light activated. These two mechanisms are interface recombination and tunneling enhanced interface recombination. The activation energy values of the saturation current density in both mechanisms were calculated from the temperature dependence of the parameters describing each of them. It was found that these values depend on temperature and illumination intensity. Furthermore, the behavior of the photovoltaic parameters could be explained relying on the results of the analysis. (Authors)

  9. Current-voltage analysis of the record-efficiency CuGaSe2 solar cell: Application of the current separation method and the interface recombination model

    International Nuclear Information System (INIS)

    Saad, M.; Kasis, A.

    2011-01-01

    Current-voltage (j-V) characteristics of the record-efficiency CuGaSe 2 solar cell measured under several illumination levels are analyzed using a two-diode equation for a more accurate description of cell behavior. The contribution of each diode to the total cell j-V characteristic under illumination was estimated using the current separation method presented recently. This is performed in an effort to identify the distinctive features of this record-efficiency cell which have led to the up-to-date highest open circuit voltage of V o c = 946 mV and fill factor of FF = 66.5% for CuGaSe 2 solar cells. Furthermore, the interface recombination component of the cell current under illumination is quantitatively discussed applying the interface recombination model presented earlier. (author)

  10. Power series fitting of current-voltage characteristics of Al doped ZnO thin film-Sb doped (Ba{sub 0.8}Sr{sub 0.2})TiO{sub 3} heterojunction diode

    Energy Technology Data Exchange (ETDEWEB)

    Sirikulrat, N., E-mail: scphi003@chiangmai.ac.th

    2012-02-29

    The current-voltage (I-V) relationship of aluminum doped zinc oxide thin film-antimony doped barium strontium titanate single heterojunction diodes was investigated. The linear I-V characteristics are similar to those of the PN junction diodes. The linear conduction at a low forward bias voltage as predicted by the space charge limited current theory and the trap free square law at a higher forward voltage are observed. The overall current density-voltage (J-V) characteristics of the diodes are found to be well described by the Power Series Equation J= N-Ary-Summation {sub m}C{sub m}V{sup m} where C{sub m} is the leakage constant at particular power m with the best fit for the power m found to be at the fourth and fifth orders for the forward and reverse bias respectively. - Highlights: Black-Right-Pointing-Pointer The n-n isotype heterojunction diodes of ceramic oxide semiconductors were prepared. Black-Right-Pointing-Pointer The current density-voltage (J-V) curves were analyzed using the Power Series (PS). Black-Right-Pointing-Pointer The J-V characteristics were found to be well described with PS at low order. Black-Right-Pointing-Pointer The thermionic emission and diode leakage currents were comparatively discussed.

  11. Thickness dependence of the poling and current-voltage characteristics of paint films made up of lead zirconate titanate ceramic powder and epoxy resin

    Science.gov (United States)

    Egusa, Shigenori; Iwasawa, Naozumi

    1995-11-01

    A specially prepared paint made up of lead zirconate titanate (PZT) ceramic powder and epoxy resin was coated on an aluminum plate and was cured at room temperature, thus forming the paint film of 25-300 μm thickness with a PZT volume fraction of 53%. The paint film was then poled at room temperature, and the poling behavior was determined by measuring the piezoelectric activity as a function of poling field. The poling behavior shows that the piezoelectric activity obtained at a given poling field increases with an increase in the film thickness from 25 to 300 μm. The current-voltage characteristic of the paint film, on the other hand, shows that the increase in the film thickness leads not only to an increase in the magnitude of the current density at a given electric field but also to an increase in the critical electric field at which the transition from the ohmic to space-charge-limited conduction takes place. This fact indicates that the amount of the space charge of electrons injected into the paint film decreases as the film thickness increases. Furthermore, comparison of the current-voltage characteristic of the paint film with that of a pure epoxy film reveals that the space charge is accumulated largely at the interface between the PZT and epoxy phases in the paint film. On the basis of this finding, a model is developed for the poling behavior of the paint film by taking into account a possible effect of the space-charge accumulation and a broad distribution of the electric field in the PZT phase. This model is shown to give an excellent fit to the experimental data of the piezoelectric activity obtained here as a function of poling field and film thickness.

  12. Analytical form of current-voltage characteristic of parallel-plane, cylindrical and spherical ionization chambers with homogeneous ionization

    Energy Technology Data Exchange (ETDEWEB)

    Stoyanov, D G [Faculty of Engineering and Pedagogy in Sliven, Technical University of Sofia, 59, Bourgasko Shaussee Blvd, 8800 Sliven (Bulgaria)

    2007-11-15

    The elementary processes taking place in the formation of charged particles and their flow in parallel-plane, cylindrical and spherical geometry cases of ionization chamber are considered. On the basis of particles and charges balance a differential equation describing the distribution of current densities in the ionization chamber volume is obtained. As a result of the differential equation solution an analytical form of the current-voltage characteristic of an ionization chamber with homogeneous ionization is obtained. For the parallel-plane case comparision with experimental data is performed.

  13. Analytical form of current-voltage characteristic of parallel-plane, cylindrical and spherical ionization chambers with homogeneous ionization

    International Nuclear Information System (INIS)

    Stoyanov, D G

    2007-01-01

    The elementary processes taking place in the formation of charged particles and their flow in parallel-plane, cylindrical and spherical geometry cases of ionization chamber are considered. On the basis of particles and charges balance a differential equation describing the distribution of current densities in the ionization chamber volume is obtained. As a result of the differential equation solution an analytical form of the current-voltage characteristic of an ionization chamber with homogeneous ionization is obtained. For the parallel-plane case comparision with experimental data is performed

  14. Influence of surface losses and the self-pumping effect on current-voltage characteristics of a long Josephson junction

    DEFF Research Database (Denmark)

    Pankratov, A.L.; Sobolev, A.S.; Koshelets, V.P.

    2007-01-01

    We have numerically investigated the dynamics of a long linear Josephson tunnel junction with overlap geometry. Biased by a direct current (dc) and an applied dc magnetic field, the junction has important applications as tunable high frequency oscillator [flux-flow oscillator (FFO......) placed at both ends of the FFO. In our model, the damping parameter depends both on the spatial coordinate and on the amplitude of the ac voltage. In order to find the dc current-voltage curves, the damping parameter has to be calculated self-consistently by successive approximations and time integration...

  15. Revisiting the role of trap-assisted-tunneling process on current-voltage characteristics in tunnel field-effect transistors

    Science.gov (United States)

    Omura, Yasuhisa; Mori, Yoshiaki; Sato, Shingo; Mallik, Abhijit

    2018-04-01

    This paper discusses the role of trap-assisted-tunneling process in controlling the ON- and OFF-state current levels and its impacts on the current-voltage characteristics of a tunnel field-effect transistor. Significant impacts of high-density traps in the source region are observed that are discussed in detail. With regard to recent studies on isoelectronic traps, it has been discovered that deep level density must be minimized to suppress the OFF-state leakage current, as is well known, whereas shallow levels can be utilized to control the ON-state current level. A possible mechanism is discussed based on simulation results.

  16. Evaluation and Testing of the Naval Postgraduate School Satellite (NPSAT1) Solar Cell Measurement System

    National Research Council Canada - National Science Library

    Lo, Benson

    2004-01-01

    .... It will trace the cells' current-voltage (I-V) curves while in orbit. The SMS consists of a radiation-hardened microcontroller that uses a radiation-hardened FPGA to monitor a collection of sensors...

  17. I-V Curves from Photovoltaic Modules Deployed in Tucson

    Science.gov (United States)

    Kopp, Emily; Brooks, Adria; Lonij, Vincent; Cronin, Alex

    2011-10-01

    More than 30 Mega Watts of photo-voltaic (PV) modules are connected to the electric power grid in Tucson, AZ. However, predictions of PV system electrical yields are uncertain, in part because PV modules degrade at various rates (observed typically in the range 0% to 3 %/yr). We present I-V curves (PV output current as a function of PV output voltage) as a means to study PV module efficiency, de-ratings, and degradation. A student-made I-V curve tracer for 100-Watt modules will be described. We present I-V curves for several different PV technologies operated at an outdoor test yard, and we compare new modules to modules that have been operated in the field for 10 years.

  18. Chronic hepatitis C in i. v. drug abusers

    Directory of Open Access Journals (Sweden)

    Lukač-Radončić Elvira

    2011-01-01

    Full Text Available In our work we present the clinical, biochemical, serologic and pathohistologic characteristics of chronic HCV infection in i. v. drag abusers treated in the Clinic for infections diseases in Kragujevac, in period of 3 years (2007-2009. year. In 17 i. v. drug abusers were examined, 13 men and 4 women, with chronic hepatitis C. Average age was 26,82 years. Duration of i. v. drug use was different from 1 year to 11 years. All patients were without com- plaints. Regarding functional liver tests level of amino-transferases was elevated: AST --50,37 Ш and ALT - 97,3 7U/1, total bilimbin was normal. On pathohistologic examination in 12 was found minimal chronic hepatitis, in 3 very active chronic hepatitis with pronounced piece meal necrosis and bridging necrosis, one patient was cirrhosis.

  19. Shunt and series resistance of photovoltaic module evaluated from the I-V curve; I-V tokusei kara hyokashita taiyo denchi no shunt teiko to chokuretsu teiko

    Energy Technology Data Exchange (ETDEWEB)

    Asano, K; Kawamura, H; Yamanaka, S; Kawamura, H; Ono, H [Meijo University, Nagoya (Japan)

    1997-11-25

    With an objective of discussing I-V characteristics when a shadow has appeared on part of a photovoltaic module, evaluations were given as a first stage of the study on saturation current, shunt resistance and series resistance for the solar cell module. As a result of measuring change in amount of power generated in a sunny day with a shadow appearing over the solar cell module, reduction in power generation capability of about 23% was verified. In other words, the I-V characteristics of the solar cell module change largely because of existence of the shadow caused on the module. The I-V characteristics curve may be expressed and calculated as a function of the shunt resistance and series resistance. By curve-fitting measurement data for a case of changing insolation without existence of partial shadow, values of the shunt resistance and series resistance were derived. As a result, it was found that the calculations agree well with measurements. It was made also clear that each parameter shows temperature dependence. 6 refs., 10 figs., 1 tab.

  20. The current-voltage relation of a pore and its asymptotic behavior in a Nernst-Planck model

    Directory of Open Access Journals (Sweden)

    Marius Birlea

    2012-08-01

    Full Text Available A model for current-voltage nonlinearity and asymmetry is a good starting point for explaining the electrical behavior of the nanopores in synthetic or biological membranes. Using a Nernst-Planck model, we found three behaviors for the current density in a membrane's pore as a function of voltage: a quasi-ohmic, slow rising linear current at low voltages, a nonlinear current at intermediate voltages, and a non-ohmic, fast rising linear current at large voltages. The slope of the quasi-ohmic current depends mainly on the height of energy barrier inside the pore, w, through an exponential term, ew. The magnitude of the non-ohmic linear current is controlled by the potential energy gradient at the pore entrance, w/r. The current-voltage relation is asymmetric if the ion's potential energy inside the pore has an asymmetric triangular profile. The model has only two assumed parameters, the energy barrier height, w, and the relative size of the entrance region of the pore, r, which is a useful feature for fitting and interpreting experimental data.

  1. Circuitry for monitoring a high direct current voltage supply for an ionization chamber

    International Nuclear Information System (INIS)

    1981-01-01

    An arrangement to measure the voltage of the supply and a switching means controlled by this is described. The voltage measurer consists of first and second signal coupling means, the input of the second (connected to the voltage supply) is connected in series with the output of the first. An ionization chamber with this circuitry may be used to monitor the radiation output of a particle accelerator more accurately. Faulty measurements of the dose output, caused by voltages in the earth circuit, are avoided. (U.K.)

  2. Modeling of planar carbon nanotube field effect transistor and three dimensional simulation of current-voltage characteristics

    International Nuclear Information System (INIS)

    Dinh Sy Hien; Nguyen Thi Luong; Thi Tran Anh Tuan; Dinh Viet Nga

    2009-01-01

    We provide a CNTFET model with planar geometry. Planar CNTFETs constitute the majority of devices fabricated to date, mostly due to their relative simplicity and moderate compatibility with existing manufacturing technologies. We explore the possibilities of using non-equilibrium Green function method to get I-V characteristics for CNTFETs. This simulator also includes a graphic user interface (GUI) of Matlab that enables parameter entry, calculation control, intuitive display of calculation results, and in-situ data analysis methods. In this paper, we review the capabilities of simulator, and give examples of typical CNTFET 3D simulations. The I-V characteristics of CNTFET are also presented.

  3. Asymptotic and numerical prediction of current-voltage curves for an organic bilayer solar cell under varying illumination and comparison to the Shockley equivalent circuit

    KAUST Repository

    Foster, J. M.; Kirkpatrick, J.; Richardson, G.

    2013-01-01

    In this study, a drift-diffusion model is used to derive the current-voltage curves of an organic bilayer solar cell consisting of slabs of electron acceptor and electron donor materials sandwiched together between current collectors. A simplified

  4. Low Noise Bias Current/Voltage References Based on Floating-Gate MOS Transistors

    DEFF Research Database (Denmark)

    Igor, Mucha

    1997-01-01

    The exploitation of floating-gate MOS transistors as reference current and voltage sources is investigated. Test structures of common source and common drain floating-gate devices have been implemented in a commercially available 0.8 micron double-poly CMOS process. The measurements performed...

  5. Plantenkaartjes uitgegeven door het I.V.O.N

    NARCIS (Netherlands)

    NN,

    1959-01-01

    De serie door het I.V.O.N. gepubliceerde verspreidingskaartjes van Nederlandse plantensoorten is wederom verkrijgbaar. De prijzen zijn als volgt: afl. 1, 1935, 21 kaartjes van diverse soorten f. 1.35 afl. 2, 1936, 32 kaartjes van diverse soorten „ 2.00 afl. 3, 1936, 18 kaartjes van Potamogeton „

  6. Microscopic theory of the current-voltage relationship across a normal-superconducting interface

    International Nuclear Information System (INIS)

    Kraehenbuehl, Y.; Watts-Tobin, R.J.

    1979-01-01

    Measurements by Pippard et al. have shown the existence of an extra resistance due to the penetration of an electrical potential into a superconductor. Previous theories of this effect are unable to explain the full temperature dependence of the extra resistance because they use oversimplified models of the normal--superconducting interface. We show that the microscopic theory for dirty superconductors leads to a good agreement with experiment over the whole temperature range

  7. Python Scripts for Automation of Current-Voltage Testing of Semiconductor Devices (FY17)

    Science.gov (United States)

    2017-01-01

    investment required by the user with manual operation, only a fraction of the total devices fabricated on a sample are actually tested. In this...only moves the stage itself in 3 dimensions. It does not control the probes or stage rotation. It is important to note that the user must first attempt...measurements using the 4155C and the manual probe station. This script bypasses the original front panel operation of the 4155C and allows the user to set

  8. Pulsed Current-Voltage-Induced Perturbations of a Premixed Propane/Air Flame

    Directory of Open Access Journals (Sweden)

    Jacob. B. Schmidt

    2011-01-01

    Full Text Available The effect of millisecond wide sub-breakdown pulsed voltage-current induced flow perturbation has been measured in premixed laminar atmospheric pressure propane/air flame. The flame equivalence ratios were varied from 0.8 to 1.2 with the flow speeds near 1.1 meter/second. Spatio-temporal flame structure changes were observed through collection of CH (A-X and OH (A-X chemiluminescence and simultaneous spontaneous Raman scattering from N2. This optical collection scheme allows us to obtain a strong correlation between the measured gas temperature and the chemiluminescence intensity, verifying that chemiluminescence images provide accurate measurements of flame reaction zone structure modifications. The experimental results suggest that the flame perturbation is caused by ionic wind originating only from the radial positive space-charge distribution in/near the cathode fall. A net momentum transfer acts along the annular space discharge distribution in the reaction zone at or near the cathode fall which modifies the flow field near the cathodic burner head. This radially inward directed body force appears to enhance mixing similar to a swirl induced modification of the flame structure. The flame fluidic response exhibit a strong dependence on the voltage pulse width ≤10 millisecond.

  9. 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.

  10. Opto-electronic analysis of silicon solar cells by LBIC investigations and current-voltage characterization

    International Nuclear Information System (INIS)

    Thantsha, N.M.; Macabebe, E.Q.B.; Vorster, F.J.; Dyk, E.E. van

    2009-01-01

    A different laser beam induced current (LBIC) mapping technique has been used for the measurements of spatial variation of light generated current of a solar cell. These variations are caused by parasitic resistances and defects at grain boundaries (GBs) in multicrystalline silicon solar cells (mc-Si). This study investigates and identifies the regions within mc-Si solar cells where dominating recombination and lifetime limiting processes occur. A description of the LBIC technique is presented and the results show how multicrystalline GBs and other defects affect the light generated current of a spot illuminated mc-Si solar cell. The results of the internal quantum efficiency (IQE) at wavelength of 660 nm revealed that some regions in mc-Si solar cell give rise to paths that lead current away from the intended load.

  11. Opto-electronic analysis of silicon solar cells by LBIC investigations and current-voltage characterization

    Energy Technology Data Exchange (ETDEWEB)

    Thantsha, N.M.; Macabebe, E.Q.B.; Vorster, F.J. [Department of Physics, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Dyk, E.E. van, E-mail: ernest.vandyk@nmmu.ac.z [Department of Physics, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2009-12-01

    A different laser beam induced current (LBIC) mapping technique has been used for the measurements of spatial variation of light generated current of a solar cell. These variations are caused by parasitic resistances and defects at grain boundaries (GBs) in multicrystalline silicon solar cells (mc-Si). This study investigates and identifies the regions within mc-Si solar cells where dominating recombination and lifetime limiting processes occur. A description of the LBIC technique is presented and the results show how multicrystalline GBs and other defects affect the light generated current of a spot illuminated mc-Si solar cell. The results of the internal quantum efficiency (IQE) at wavelength of 660 nm revealed that some regions in mc-Si solar cell give rise to paths that lead current away from the intended load.

  12. Thermal domains in inhomogeneous current-carrying superconductors. Current-voltage characteriscs and dynamics of domain formation after current jumps

    International Nuclear Information System (INIS)

    Bezuglyj, A.I.; Shklovskij, V.A.

    1984-01-01

    The static and dynamic behavior of thermal domains in inhomogeneous superconducting films, where the inhomogeneity behaves like a portion of the film with a reduced critical current, have been studied theoretically within the framework of the phenomenological approach, using the heat balance equation and the dependence of the superconductor critical current on temperature. Depending on the size of the inhomogeneity (local or extended) and on the relative values of parameters of the homogeneous and inhomogeneous regions, different types of current-voltage characteristics are obtained. The nonstationary problem of thermal domain formation near the inhomogeneity after a current jump has been solved, and the domain boundary (kink) dynamics at a distance from the inhomogeneity has been analyzed. A combination of the results allows one to describe the whole process of normal phase formation and its spread throughout the superconducting film

  13. 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

  14. Poly-benzyl domains grown on porous silicon and their I-V rectification

    International Nuclear Information System (INIS)

    Chao Jie; Han Huanmei; Xia Bing; Ba Long; Liu Hongbo; Xiao Shoujun

    2007-01-01

    Microwave-irradiated polymerization of benzyl chloride and triphenyl chloromethane on hydride-terminated porous silicon (PS) was achieved through the use of Zn powder as a catalyst. Transmission infrared Fourier-transform spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses confirmed the poly-benzyl membranes grafted on PS. Topographical images by AFM revealed crystal-like domains rather than homogenous monolayers on the surface. The current-voltage measurements in nano-scale by current sensing atomic force microscopy (CS-AFM) showed the rectification behavior of this polymer membrane. Finally, mechanism of a radical initiation on the surface and a following Friedel-Crafts alkylation was proposed for the covalent assembly of poly-benzyl domains

  15. Effect of band gap narrowing on GaAs tunnel diode I-V characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Lebib, A.; Hannanchi, R. [Laboratoire d' énergie et de matériaux, LabEM-LR11ES34-Université de sousse (Tunisia); Beji, L., E-mail: lotbej_fr@yahoo.fr [Laboratoire d' énergie et de matériaux, LabEM-LR11ES34-Université de sousse (Tunisia); EL Jani, B. [Unité de Recherche sur les Hétéro-Epitaxies et Applications, Faculté des Sciences, Université de Monastir, 5019 Monastir (Tunisia)

    2016-12-01

    We report on experimental and theoretical study of current-voltage characteristics of C/Si-doped GaAs tunnel diode. For the investigation of the experimental data, we take into account the band-gap narrowing (BGN) effect due to heavily-doped sides of the tunnel diode. The BGN of the n- and p-sides of tunnel diode was measured by photoluminescence spectroscopy. The comparison between theoretical results and experimental data reveals that BGN effect enhances tunneling currents and hence should be considered to identify more accurately the different transport mechanisms in the junction. For C/Si-doped GaAs tunnel diode, we found that direct tunneling is the dominant transport mechanism at low voltages. At higher voltages, this mechanism is replaced by the rate-controlling tunneling via gap states in the forbidden gap.

  16. High-temperature performance of MoS{sub 2} thin-film transistors: Direct current and pulse current-voltage characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, C.; Samnakay, R.; Balandin, A. A., E-mail: balandin@ee.ucr.edu [Nano-Device Laboratory (NDL), Department of Electrical Engineering, Bourns College of Engineering, University of California—Riverside, Riverside, California 92521 (United States); Phonon Optimized Engineered Materials (POEM) Center, Materials Science and Engineering Program, University of California—Riverside, Riverside, California 92521 (United States); Rumyantsev, S. L. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Ioffe Physical-Technical Institute, St. Petersburg 194021 (Russian Federation); Shur, M. S. [Department of Electrical, Computer, and Systems Engineering, Center for Integrated Electronics, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-02-14

    We report on fabrication of MoS{sub 2} thin-film transistors (TFTs) and experimental investigations of their high-temperature current-voltage characteristics. The measurements show that MoS{sub 2} devices remain functional to temperatures of at least as high as 500 K. The temperature increase results in decreased threshold voltage and mobility. The comparison of the direct current (DC) and pulse measurements shows that the direct current sub-linear and super-linear output characteristics of MoS{sub 2} thin-films devices result from the Joule heating and the interplay of the threshold voltage and mobility temperature dependences. At temperatures above 450 K, a kink in the drain current occurs at zero gate voltage irrespective of the threshold voltage value. This intriguing phenomenon, referred to as a “memory step,” was attributed to the slow relaxation processes in thin films similar to those in graphene and electron glasses. The fabricated MoS{sub 2} thin-film transistors demonstrated stable operation after two months of aging. The obtained results suggest new applications for MoS{sub 2} thin-film transistors in extreme-temperature electronics and sensors.

  17. Ozone and dinitrogen monoxide production in atmospheric pressure air dielectric barrier discharge plasma effluent generated by nanosecond pulse superimposed alternating current voltage

    Science.gov (United States)

    Takashima, Keisuke; Kaneko, Toshiro

    2017-06-01

    The effects of nanosecond pulse superposition to alternating current voltage (NS + AC) on the generation of an air dielectric barrier discharge (DBD) plasma and reactive species are experimentally studied, along with measurements of ozone (O3) and dinitrogen monoxide (N2O) in the exhausted gas through the air DBD plasma (air plasma effluent). The charge-voltage cycle measurement indicates that the role of nanosecond pulse superposition is to induce electrical charge transport and excess charge accumulation on the dielectric surface following the nanosecond pulses. The densities of O3 and N2O in NS + AC DBD are found to be significantly increased in the plasma effluent, compared to the sum of those densities generated in NS DBD and AC DBD operated individually. The production of O3 and N2O is modulated significantly by the phase in which the nanosecond pulse is superimposed. The density increase and modulation effects by the nanosecond pulse are found to correspond with the electrical charge transport and the excess electrical charge accumulation induced by the nanosecond pulse. It is suggested that the electrical charge transport by the nanosecond pulse might result in the enhancement of the nanosecond pulse current, which may lead to more efficient molecular dissociation, and the excess electrical charge accumulation induced by the nanosecond pulse increases the discharge coupling power which would enhance molecular dissociation.

  18. The role of bulk and interface states on performance of a-Si: H p-i-n solar cells using reverse current-voltage technique

    International Nuclear Information System (INIS)

    Mahmood, S A; Kabir, M Z; Murthy, R V R; Dutta, V

    2009-01-01

    The defect state densities in the bulk of the i-layer and at the p/i interface have been studied in hydrogenated amorphous silicon (a-Si : H) solar cells using reverse current-voltage (J-V) measurements. In this work the cells have been soaked with blue and red lights prior to measurements. The voltage-dependent reverse current has been analysed on the basis of thermal generation of the carriers from midgap states in the i-layer and the carrier injection through the p/i interface. Based on the reverse current behaviour, it has been analysed that at lower reverse bias (reverse voltage, V r r ∼ 25 V) the defect states at the p/i interface are contributing to the reverse currents. The applied reverse bias annealing (RBA) treatment on these cells shows more significant annihilation of defect states at the p/i interface as compared with the bulk of the i-layer. An analytical model is developed to explain the observed behaviour. There is good agreement between the theory and the experimental observations. The fitted defect state densities are 9.1 x 10 15 cm -3 and 8 x 10 18 cm -3 in the bulk of the i-layer and near the p/i interface, respectively. These values decrease to 2.5 x 10 15 cm -3 and 6 x 10 17 cm -3 , respectively, in the samples annealed under reverse bias at 2 V.

  19. Vortex instability and hysteresis effects in I-V curves of superconducting Y1Ba2Cu3O7-δ

    International Nuclear Information System (INIS)

    Kilic, A.; Kilic, K.; Cetin, O.

    2003-01-01

    We have investigated the effect of the current sweep rate (CSR) on the vortex dynamics in superconducting bulk sample of Y 1 Ba 2 Cu 3 O 7-δ . It has been found that the CSR has several dramatic effects on the vortex motion by giving rise enhancement in dissipation as decreasing the CSR, significant time effects, and instabilities in current-voltage (I-V) curves. The hysteresis loops concerning the I-V curves in both the current-increase and -decrease branches of the forward current region, and also the branches of the reversed current region have been observed together with a gradual diminutive of the hysteresis effects with decreasing the CSR. Due to the field and temperature domain considered, it is also observed that the moving state becomes unstable giving rise some instabilities such as small jumps and steps for both low and moderate current values as a function of CSR. Those anomalies have been discussed in terms of the depinning-pinning correlated to the plastic flow regime together with the disorder in the coupling strength between the superconducting grains, and compared qualitatively to the numerical computer simulations. In addition, for a given field and temperature domain, it has been shown that the CSR together with a relevant current scale is of importance in evolution of the I-V curves and is a useful tool in investigating the details of the vortex dynamics

  20. Defect States in InP/InGaAs/InP Heterostructures by Current-Voltage Characteristics and Deep Level Transient Spectroscopy.

    Science.gov (United States)

    Vu, Thi Kim Oanh; Lee, Kyoung Su; Lee, Sang Jun; Kim, Eun Kyu

    2018-09-01

    We studied defect states in In0.53Ga0.47As/InP heterojunctions with interface control by group V atoms during metalorganic chemical vapor (MOCVD) deposition. From deep level transient spectroscopy (DLTS) measurements, two defects with activation energies of 0.28 eV (E1) and 0.15 eV (E2) below the conduction band edge, were observed. The defect density of E1 for In0.53Ga0.47As/InP heterojunctions with an addition of As and P atoms was about 1.5 times higher than that of the heterojunction added P atom only. From the temperature dependence of current- voltage characteristics, the thermal activation energies of In0.53Ga0.47As/InP of heterojunctions were estimated to be 0.27 and 0.25 eV, respectively. It appeared that the reverse light current for In0.53Ga0.47As/InP heterojunction added P atom increased only by illumination of a 940 nm-LED light source. These results imply that only the P addition at the interface can enhance the quality of InGaAs/InP heterojunction.

  1. The current-voltage characteristic and potential oscillations of a double layer in a triple plasma device

    International Nuclear Information System (INIS)

    Carpenter, R.T.; Torven, S.

    1986-07-01

    The properties of a strong double layer in a current circuit with a capacitance and an inductance are investigated in a triple plasma device. The double layer gives rise to a region of negative differential resistance in the current-voltage characteristic of the device, and this gives non-linear oscillations in the current and the potential drop over the double layer (PhiDL). For a sufficiently large circuit inductance PhiDL reaches an amplitude given by the induced voltage (-LdI/dt) which is much larger than the circuit EMF due to the rapid current decrease when PhiDL increases. A variable potential minimum exists in the plasma on the low potential side of the double layer, and the depth of the minimum increases when PhiDL increases. An increasing fraction of the electrons incident at the double layer are then reflected, and this is found to be the main process giving rise to the negative differential resistance. A qualitative model for the variation of the minimum potential with PhiDL is also proposed. It is based on the condition that the minimum potential must adjust itself self-consistentely so that quasi-neutrality is maintained in the plasma region where the minimum is assumed. (authors)

  2. Current, voltage and temperature distribution modeling of light-emitting diodes based on electrical and thermal circuit analysis

    International Nuclear Information System (INIS)

    Yun, J; Shim, J-I; Shin, D-S

    2013-01-01

    We demonstrate a modeling method based on the three-dimensional electrical and thermal circuit analysis to extract current, voltage and temperature distributions of light-emitting diodes (LEDs). In our model, the electrical circuit analysis is performed first to extract the current and voltage distributions in the LED. Utilizing the result obtained from the electrical circuit analysis as distributed heat sources, the thermal circuit is set up by using the duality between Fourier's law and Ohm's law. From the analysis of the thermal circuit, the temperature distribution at each epitaxial film is successfully obtained. Comparisons of experimental and simulation results are made by employing an InGaN/GaN multiple-quantum-well blue LED. Validity of the electrical circuit analysis is confirmed by comparing the light distribution at the surface. Since the temperature distribution at each epitaxial film cannot be obtained experimentally, the apparent temperature distribution is compared at the surface of the LED chip. Also, experimentally obtained average junction temperature is compared with the value calculated from the modeling, yielding a very good agreement. The analysis method based on the circuit modeling has an advantage of taking distributed heat sources as inputs, which is essential for high-power devices with significant self-heating. (paper)

  3. Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics Individualized Learning System. CANTRAC A-100-0010. Module Five: Relationships of Current, Voltage, and Resistance. Study Booklet.

    Science.gov (United States)

    Chief of Naval Education and Training Support, Pensacola, FL.

    This individualized learning module on the relationships of current, voltage, and resistance is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptaticn to vocational instructional and curriculum development in a civilian setting.…

  4. Electrical Characterization of Gold-DNA-Gold Structures in Presence of an External Magnetic Field by Means of I-V Curve Analysis

    Directory of Open Access Journals (Sweden)

    Wan Haliza Abd Majid

    2012-03-01

    Full Text Available This work presents an experimental study of gold-DNA-gold structures in the presence and absence of external magnetic fields with strengths less than 1,200.00 mT. The DNA strands, extracted by standard method were used to fabricate a Metal-DNA-Metal (MDM structure. Its electric behavior when subjected to a magnetic field was studied through its current-voltage (I-V curve. Acquisition of the I-V curve demonstrated that DNA as a semiconductor exhibits diode behavior in the MDM structure. The current versus magnetic field strength followed a decreasing trend because of a diminished mobility in the presence of a low magnetic field. This made clear that an externally imposed magnetic field would boost resistance of the MDM structure up to 1,000.00 mT and for higher magnetic field strengths we can observe an increase in potential barrier in MDM junction. The magnetic sensitivity indicates the promise of using MDM structures as potential magnetic sensors.

  5. Investigation of the double exponential in the current-voltage characteristics of silicon solar cells. [proton irradiation effects on ATS 1 cells

    Science.gov (United States)

    Wolf, M.; Noel, G. T.; Stirn, R. J.

    1977-01-01

    Difficulties in relating observed current-voltage characteristics of individual silicon solar cells to their physical and material parameters were underscored by the unexpected large changes in the current-voltage characteristics telemetered back from solar cells on the ATS-1 spacecraft during their first year in synchronous orbit. Depletion region recombination was studied in cells exhibiting a clear double-exponential dark characteristic by subjecting the cells to proton irradiation. A significant change in the saturation current, an effect included in the Sah, Noyce, Shockley formulation of diode current resulting from recombination in the depletion region, was caused by the introduction of shallow levels in the depletion region by the proton irradiation. This saturation current is not attributable only to diffusion current from outside the depletion region and only its temperature dependence can clarify its origin. The current associated with the introduction of deep-lying levels did not change significantly in these experiments.

  6. Asymptotic and numerical prediction of current-voltage curves for an organic bilayer solar cell under varying illumination and comparison to the Shockley equivalent circuit

    KAUST Repository

    Foster, J. M.

    2013-01-01

    In this study, a drift-diffusion model is used to derive the current-voltage curves of an organic bilayer solar cell consisting of slabs of electron acceptor and electron donor materials sandwiched together between current collectors. A simplified version of the standard drift-diffusion equations is employed in which minority carrier densities are neglected. This is justified by the large disparities in electron affinity and ionisation potential between the two materials. The resulting equations are solved (via both asymptotic and numerical techniques) in conjunction with (i) Ohmic boundary conditions on the contacts and (ii) an internal boundary condition, imposed on the interface between the two materials, that accounts for charge pair generation (resulting from the dissociation of excitons) and charge pair recombination. Current-voltage curves are calculated from the solution to this model as a function of the strength of the solar charge generation. In the physically relevant power generating regime, it is shown that these current-voltage curves are well-approximated by a Shockley equivalent circuit model. Furthermore, since our drift-diffusion model is predictive, it can be used to directly calculate equivalent circuit parameters from the material parameters of the device. © 2013 AIP Publishing LLC.

  7. The nonideality coefficient of current-voltage characteristics for p-n junctions in a high ultrahigh-frequency (microwave) field

    International Nuclear Information System (INIS)

    Shamirzaev, S. H.; Gulyamov, G.; Dadamirzaev, M. G.; Gulyamov, A. G.

    2009-01-01

    The effect of heating of electrons and holes on the nonideality coefficient of the current-voltage characteristic for a p-n junction in a high microwave field is studied. It is established that the nonideality coefficient for a diode depends on the type of charge carriers that make the major contribution to the current in the p-n junction. It is shown that, in some cases in silicon samples, the nonideality coefficient for the diode is governed by the temperature for holes in spite of the fact that the temperature for electrons is higher than the temperature for holes.

  8. Observation and investigation of a dynamic inflection point in current-voltage curves for roll-to-roll processed polymer photovoltaics

    DEFF Research Database (Denmark)

    Medford, Andrew James; Lilliedal, Mathilde Raad

    2010-01-01

    Inflection point behaviour is often observed in the current-voltage (IV) curve of polymer and organic solar cells. This phenomenon is examined in the context of flexible roll-to-roll (R2R) processed polymer solar cells in a large series of devices with a layer structure of: PET-ITO-ZnO-P3HT...... of this “photo-annealing” behaviour was further investigated by studying the effects of several key factors: temperature, illumination, and atmosphere. The results consistently showed that the inflection point is a dynamic interface phenomenon which can be removed under specific conditions. Subsequently...

  9. USTUR WHOLE BODY CASE 0269: DEMONSTRATING EFFECTIVENESS OF I.V. CA-DTPA FOR PU

    Energy Technology Data Exchange (ETDEWEB)

    James, Anthony C.; Sasser , Lyle B.; Stuit, Dorothy B.; Glover, Samuel E.; Carbaugh, Eugene H.

    2008-01-28

    This whole body donation case (USTUR Registrant) involved a single acute inhalation of an acidic Pu(NO3)4 solution in the form of an aerosol ‘mist.’ Chelation treatment with i.v. Ca-EDTA was initiated on the day of the intake, and continued intermittently over 6 months. After 2½ years with no further treatment, a course of i.v. Ca-DTPA was administered. A total of 400 measurements of 239+240Pu excreted in urine were recorded; starting on the first day (both before and during the initial Ca-EDTA chelation), and continuing for 37 years. This sampling included all intervals of chelation. In addition, 91 measurements of 239+240Pu-in-feces were recorded over this whole period. The Registrant died about 38 years after the intake, at age 79 y, with extensive carcinomatosis secondary to adenocarcinoma of the prostate gland. At autopsy, all major soft tissue organs were harvested for radiochemical analyses of their 238Pu, 239+240Pu and 241Am content. Also, all types of bone (comprising about half the skeleton) were harvested for radiochemical analyses, as well as samples of skin, subcutaneous fat and muscle. This comprehensive dataset has been applied to derive ‘chelation-enhanced’ transfer rates in the ICRP Publication 67 plutonium biokinetic model, representing the behaviour of blood-borne and tissue-incorporated plutonium during intervals of therapy. The resulting model of the separate effects of i.v. Ca-EDTA and Ca-DTPA chelation shows that the therapy administered in this case succeeded in reducing substantially the long-term burden of plutonium in all body organs, except for the lungs. The calculated reductions in organ content at the time of death are approximately 40% for the liver, 60% for other soft tissues (muscle, skin, glands, etc.), 50% for the kidneys, and 50% for the skeleton. Essentially all of the substantial reduction in skeletal burden occurred in trabecular bone. This modeling exercise demonstrated that 3-y-delayed Ca-DTPA therapy was as

  10. Ustur whole body case 0269: demonstrating effectiveness of i.v. CA-DTPA for Pu

    Energy Technology Data Exchange (ETDEWEB)

    James, A.C.; Sasser, L.B.; Stuit, D.B. [US Transuranium and Uranium Registries, College of Pharmacy, Washington State University, 1845 Terminal Drive, Suite 201, Richland, WA 99354 (United States); Glover, S.E. [Department of Mechanical, Industrial and Nuclear Engineering, University of Cincinnati, 598 Rhodes Hall, Cincinnati, OH 45221 (United States); Carbaugh, E.H. [Pacific Northwest National Laboratory, PO Box 999, Richland, WA 99354 (United States)

    2007-07-01

    This whole body donation case (USTUR Registrant) involved a single acute inhalation of an acidic Pu(NO{sub 3}){sub 4} solution in the form of an aerosol 'mist'. Chelation treatment with intravenously (i.v.) Ca-EDTA was initiated on the day of the intake, and continued intermittently over 6 months. After 2.5 y with no further treatment, a course of i.v. Ca-DTPA was administered. A total of 400 measurements of {sup 239+240}Pu excreted in urine were recorded; starting on the first day (both before and during the initial Ca-EDTA chelation) and continuing for 37 y. This sampling included all intervals of chelation. In addition, 91 measurements of {sup 239+240}Pu-in-feces were recorded over this whole period. The Registrant died about 38 y after the intake, at age 79 y, with extensive carcinomatosis secondary to adenocarcinoma of the prostate gland. At autopsy, all major soft tissue organs were harvested for radiochemical analyses of their {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am content. Also, all types of bone (comprising about half the skeleton) were harvested for radiochemical analyses, as well as samples of skin, subcutaneous fat and muscle. This comprehensive data set has been applied to derive 'chelation-enhanced' transfer rates in the ICRP Publication 67 plutonium biokinetic model, representing the behaviour of blood-borne and tissue-incorporated plutonium during intervals of therapy. The resulting model of the separate effects of i.v. Ca-EDTA and Ca-DTPA chelation shows that the therapy administered in this case succeeded in reducing substantially the long-term burden of plutonium in all body organs, except for the lungs. The calculated reductions in organ content at the time of death are {approx}40% for the liver, 60% for other soft tissues (muscle, skin, glands, etc.), 50% for the kidneys and 50% for the skeleton. Essentially, all of the substantial reduction in skeletal burden occurred in trabecular bone. This modelling exercise

  11. Effect of i.v. dextrose administration on glucose metabolism during surgery.

    Science.gov (United States)

    Schricker, Thomas; Lattermann, Ralph; Wykes, Linda; Carli, Franco

    2004-01-01

    The inhibitory influence of exogenous dextrose on glucose production has been shown to be less pronounced during injury and sepsis. This protocol was designed to investigate the effect of i.v. hypocaloric dextrose on glucose metabolism during elective abdominal surgery. Fourteen patients with rectal cancer were studied under fasting conditions and toward the end of a 3-hour infusion of dextrose (2 mg.kg-1 per minute) either in absence (control group, n = 7) or presence of colonic surgery (surgery group, n = 7). Endogenous glucose production was determined by using primed continuous infusions of [6,6-2H2]glucose before and during dextrose administration. We also measured the plasma concentrations of glucose, lactate, cortisol, glucagon, and insulin. The administration of dextrose decreased the endogenous glucose production in all patients (p dextrose infusion in both groups (p Dextrose infusion increased the plasma insulin concentrations to the same extent in both groups (p dextrose on endogenous glucose production.

  12. I-V curves of Y-Ba-Cu-O microbridges in the flux flow regime

    International Nuclear Information System (INIS)

    Kalisky, B.; Wolfus, Y.; Yeshurun, Y.; Koren, G.; Huebener, R.P.

    2004-01-01

    We report on measurements of I-V curves in microbridges of thin Y-Ba-Cu-O films of different thickness, in the presence of external magnetic fields up to 6 T. A discontinuity is observed at a critical voltage, V*, in the flux flow regime, reflecting an electronic instability, as predicted by Larkin and Ovchinnikov (LO), and in agreement with results reported by Doettinger et al. [Phys. Rev. Let. 73 (1994) 1691]. The critical voltage, V*, and the flux flow resistance, R 0 , in the limit V→0, are calculated by fitting the data to the LO model. We find that the vortex critical velocity, v*, at the instability, derived from V*, decreases with magnetic field and film thickness. These results, not predicted by the LO theory, reflect the dependence of the (spatially averaged) quasiparticle energy relaxation rate on magnetic field and film thickness

  13. Rapid contrast infusion of bolus injection for i.v. urography

    International Nuclear Information System (INIS)

    Kaltenborn, H.; Klose, P.; Klose, K.; Schmiedel, E.

    1993-01-01

    The rate of contrast injection during i.v. urography may vary considerably (bolus injection or drip infusion). The effect of 5 rates of injection (6, 12, 18, 36 and 72 ml/min) on the contrast density in the renal collecting system was examined over a period of 30 minutes. Measurements showed an inter-individual difference of more than 200% in each group. The intra-individual variations for different rates of injection were very slight; individual concentration in the kidney for a given dose depends only slightly on the rate of injection. There is no statistically significant improvement in contrast values as a result of a bolus injection. The reduced incidence of side effects justifies the use of bolus injections but pressure injections are unnecessary from a diagnostic point view. (orig.) [de

  14. Manifestation of vortex depinning transition in nonlinear current-voltage characteristics of polycrystalline superconductor Y1-xPrxBa2Cu3O7-δ

    International Nuclear Information System (INIS)

    Rivera, V.A.G.; Stari, C.; Sergeenkov, S.; Marega, E.; Araujo-Moreira, F.M.

    2008-01-01

    We present our recent results on the temperature dependence of current-voltage characteristics for polycrystalline Y 1-x Pr x Ba 2 Cu 3 O 7-δ superconductors with x=0.0, 0.1 and 0.3. The experimental results are found to be reasonably well fitted for all samples by a power like law of the form V=R(I-I c ) a(T) . Here, we assume that a(T)=1+Φ 0 I C (T)/2πk B T and I C (T)=I C (0)(1-T/T C ) 3/2 for the temperature dependences of the power exponent and critical current, respectively. According to the theoretical interpretation of the obtained results, nonlinear deviation of our current-voltage characteristics curves from Ohmic behavior (with a(T C )=1) below T C is attributed to the manifestation of dissipation processes. They have a characteristic temperature T p defined via the power exponent as a(T p )=2 and are related to the current induced depinning of Abrikosov vortices. Both T C (x) and T p (x) are found to decrease with an increase of Pr concentration x reflecting deterioration of the superconducting properties of the doped samples

  15. Peripheral i.v. analysis (PIVA) of venous waveforms for volume assessment in patients undergoing haemodialysis.

    Science.gov (United States)

    Hocking, K M; Alvis, B D; Baudenbacher, F; Boyer, R; Brophy, C M; Beer, I; Eagle, S

    2017-12-01

    The assessment of intravascular volume status remains a challenge for clinicians. Peripheral i.v. analysis (PIVA) is a method for analysing the peripheral venous waveform that has been used to monitor volume status. We present a proof-of-concept study for evaluating the efficacy of PIVA in detecting changes in fluid volume. We enrolled 37 hospitalized patients undergoing haemodialysis (HD) as a controlled model for intravascular volume loss. Respiratory rate (F0) and pulse rate (F1) frequencies were measured. PIVA signal was obtained by fast Fourier analysis of the venous waveform followed by weighing the magnitude of the amplitude of the pulse rate frequency. PIVA was compared with peripheral venous pressure and standard monitoring of vital signs. Regression analysis showed a linear correlation between volume loss and change in the PIVA signal (R2=0.77). Receiver operator curves demonstrated that the PIVA signal showed an area under the curve of 0.89 for detection of 20 ml kg-1 change in volume. There was no correlation between volume loss and peripheral venous pressure, blood pressure or pulse rate. PIVA-derived pulse rate and respiratory rate were consistent with similar numbers derived from the bio-impedance and electrical signals from the electrocardiogram. PIVA is a minimally invasive, novel modality for detecting changes in fluid volume status, respiratory rate and pulse rate in spontaneously breathing patients with peripheral i.v. cannulas. © The Author 2017. Published by Oxford University Press on behalf of the British Journal of Anaesthesia. All rights reserved. For Permissions, please email: journals.permissions@oup.com

  16. An automatic method to analyze the Capacity-Voltage and Current-Voltage curves of a sensor

    CERN Document Server

    AUTHOR|(CDS)2261553

    2017-01-01

    An automatic method to perform Capacity versus voltage analysis for all kind of silicon sensor is provided. It successfully calculates the depletion voltage to unirradiated and irradiated sensors, and with measurements with outliers or reaching breakdown. It is built using C++ and using ROOT trees with an analogous skeleton as TRICS, where the data as well as the results of the ts are saved, to make further analysis.

  17. DFT coupled with NEGF study of ultra-sensitive HCN and HNC gases detection and distinct I-V response based on phosphorene.

    Science.gov (United States)

    Pang, Jiu; Yang, Qun; Ma, Xiaosong; Wang, Liming; Tan, Chunjian; Xiong, Daxi; Ye, Huaiyu; Chen, Xianping

    2017-11-22

    The sensing performances of pristine and X-doped phosphorene substrates (X = Al, Si, and S atoms) toward the adsorption of the toxic gases HCN and HNC were systematically investigated by first-principles simulations. The numerical results show that the pristine phosphorene is sensitive to HCN and HNC molecules with moderate adsorption energy, excellent charge transfer, high sensitivity and selectivity, implying its potential applications as excellent HCN and HNC sensors. In addition, the Al-doped phosphorene exhibits extremely high reactive activity toward HCN and HNC gases; thus, it has potential for use as a metal-free catalyst for activating or catalyzing HCN or HNC adsorbates. Moreover, the transport properties, i.e., current-voltage (I-V) characteristics, were calculated by the non-equilibrium Green's function (NEGF) method within the framework of the density functional theory (DFT). The obtained results reveal that the adsorbed HCN or HNC gas molecules have a remarkable impact on the electronic conductivity of phosphorene, and the zigzag direction of phosphorene is more sensitive to gas molecules than the armchair direction. The combination of the high sensitivity, superior selectivity, and moderate adsorption energy of pristine phosphorene toward HCN or HNC gas molecules adsorption, makes phosphorene an excellent candidate for HCN and HNC sensors.

  18. Analysis of high field effects on the steady-state current-voltage response of semi-insulating 4H-SiC for photoconductive switch applications

    Energy Technology Data Exchange (ETDEWEB)

    Tiskumara, R. [Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, Virginia 23529 (United States); Joshi, R. P., E-mail: ravi.joshi@ttu.edu; Mauch, D.; Dickens, J. C.; Neuber, A. A. [Department of Electrical and Computer Engineering, Texas Tech University, Lubbock, Texas 79409 (United States)

    2015-09-07

    A model-based analysis of the steady-state, current-voltage response of semi-insulating 4H-SiC is carried out to probe the internal mechanisms, focusing on electric field driven effects. Relevant physical processes, such as multiple defects, repulsive potential barriers to electron trapping, band-to-trap impact ionization, and field-dependent detrapping, are comprehensively included. Results of our model match the available experimental data fairly well over orders of magnitude variation in the current density. A number of important parameters are also extracted in the process through comparisons with available data. Finally, based on our analysis, the possible presence of holes in the samples can be discounted up to applied fields as high as ∼275 kV/cm.

  19. Current-voltage characterization of Au contact on sol-gel ZnO films with and without conducting polymer

    International Nuclear Information System (INIS)

    Lin, Yow-Jon; Jheng, Mei-Jyuan; Zeng, Jian-Jhou

    2010-01-01

    This study investigates the current density-voltage (J-V) characteristics of Au/n-type ZnO and Au/polyaniline (PANI)/n-type ZnO devices. ZnO films were prepared by the sol-gel method. For Au/n-type ZnO devices, native defects and impurities resident within the ZnO depletion region contribute to barrier thinning of, carrier hopping across, and tunneling through the Schottky barrier. This leads to the formation of nonalloyed ohmic contacts. However, rectifying junctions were formed on n-type ZnO by employing the simple technique of spin-coating PANI to act as the electron-blocking layer. Our present results suggest that the ZnO depletion region at the PANI/n-type ZnO interface is not the origin of the rectifying behavior of Au/PANI/n-type ZnO contact. In addition, the presence of the built-in potential of Au/PANI/n-type ZnO devices could result in the shift of the J-V curve toward negative voltage. Excellent agreement between simulated and measured data was obtained when the built-in potential was taken into account in the J-V relationship.

  20. I-V Characteristics of a Static Random Access Memory Cell Utilizing Ferroelectric Transistors

    Science.gov (United States)

    Laws, Crystal; Mitchell, Cody; Hunt, Mitchell; Ho, Fat D.; MacLeod, Todd C.

    2012-01-01

    I-V characteristics for FeFET different than that of MOSFET Ferroelectric layer features hysteresis trend whereas MOSFET behaves same for both increasing and decreasing VGS FeFET I-V characteristics doesn't show dependence on VDS A Transistor with different channel length and width as well as various resistance and input voltages give different results As resistance values increased, the magnitude of the drain current decreased.

  1. A FAST study of quasi-static structure ("Inverted-V") potential drops and their latitudinal dependence in the premidnight sector and ramifications for the current-voltage relationship

    Science.gov (United States)

    Dombeck, J.; Cattell, C.; McFadden, J.

    2013-09-01

    Utilizing FAST satellite electron measurements, we present the first reported investigation of the dependency on latitude of quasi-static structure ("inverted-V") potential drop magnitude (Φ). A trend of lower Φ at lower latitudes in the premidnight sector on field lines with dark foot points was observed. This trend is supported both statistically and in individual satellite crossings. The existence of two distinct peaks in occurrence probability for Φ was also observed: one between ~2 kV and 10 kV and the other at somewhat less than 1 kV. The relative occurrence of structures with Φ in the higher (>2 kV) peak is significantly reduced with decreasing latitude. This partially accounts for the statistical trend of lower potential drop magnitudes at lower latitudes. The two Φ occurrence frequency peaks correspond to two different regimes (one with eΦ/kTe ~ or > 1 and one with eΦ/kTe current-voltage relation where source electron density rather than Φ is most directly controlled by the field-aligned current density. These observations and their ramifications represent a significant step forward in the understanding of field-aligned currents, auroral acceleration, and magnetospheric-ionospheric coupling.

  2. I-V characteristic of electronic transport through a quantum dot chain: The role of antiresonance

    International Nuclear Information System (INIS)

    Liu Yu; Zheng Yisong; Gong Weijiang; Lue Tianquan

    2006-01-01

    The I-V spectrum of electronic transport through a quantum dot chain is calculated by means of the nonequilibrium Green function technique. In such a system, two arbitrary quantum dots are connected with two electron reservoirs through leads. When the dot-lead coupling is very weak, a series of discrete resonant peaks in electron transmission function cause staircase-like I-V characteristic. On the contrary, in the relatively strong dot-lead coupling regime, stairs in the I-V spectrum due to resonance vanish. However, when there are some dangling quantum dots in the chain outside two leads, the antiresonance which corresponds to the zero points of electron transmission function brings about novel staircase characteristic in the I-V spectrum. Moreover, two features in the I-V spectrum arising from the antiresonance are pointed out, which are significant for possible device applications. One is the multiple negative differential conductance regions, and another is regarding to create a highly spin-polarized current through the quantum dot chain by the interplay of the resonance and antiresonance. Finally, we focus on the role that the many-body effect plays on the antiresonance. Our result is that the antiresonance remains when the electron interaction is considered to the second order approximation

  3. Current-Voltage and Floating-Potential characteristics of cylindrical emissive probes from a full-kinetic model based on the orbital motion theory

    Science.gov (United States)

    Chen, Xin; Sánchez-Arriaga, Gonzalo

    2018-02-01

    To model the sheath structure around an emissive probe with cylindrical geometry, the Orbital-Motion theory takes advantage of three conserved quantities (distribution function, transverse energy, and angular momentum) to transform the stationary Vlasov-Poisson system into a single integro-differential equation. For a stationary collisionless unmagnetized plasma, this equation describes self-consistently the probe characteristics. By solving such an equation numerically, parametric analyses for the current-voltage (IV) and floating-potential (FP) characteristics can be performed, which show that: (a) for strong emission, the space-charge effects increase with probe radius; (b) the probe can float at a positive potential relative to the plasma; (c) a smaller probe radius is preferred for the FP method to determine the plasma potential; (d) the work function of the emitting material and the plasma-ion properties do not influence the reliability of the floating-potential method. Analytical analysis demonstrates that the inflection point of an IV curve for non-emitting probes occurs at the plasma potential. The flat potential is not a self-consistent solution for emissive probes.

  4. Method for estimation of the output electric power of PV module with considering environmental factors. Method for estimation of output using I-V curves; Kankyo inshi wo koryoshita taiyo denchi module no shutsuryoku keisanho. I-V tokusei curve ni yoru keisan

    Energy Technology Data Exchange (ETDEWEB)

    Yamagami, Y; Tani, T [Science University of Tokyo, Tokyo (Japan)

    1996-10-27

    Based on the basic quality equation of photovoltaic (PV) cell, a quality equation of PV module has been constructed by considering the spectral distribution of solar radiation and its intensity. A calculation method has been also proposed for determining the output from current-voltage (I-V) curves. Effectiveness of this method was examined by comparing calculated results and observed results. Amorphous Si (a-Si) and polycrystal Si PV modules were examined. By considering the environmental factors, differences of the annual output between the calculated and observed values were reduced from 2.50% to 0.95% for the a-Si PV module, and from 2.52% to 1.24% for the polycrystal Si PV module, which resulted in the reduction more than 50%. For the a-Si PV module, the environmental factor most greatly affecting the annual output was the spectral distribution of solar radiation, which was 3.86 times as large as the cell temperature, and 1.04 times as large as the intensity of solar radiation. For the polycrystal PV module, the environmental factor most greatly affecting the annual output was the cell temperature, which was 7.05 times as large as the spectral distribution of solar radiation, and 1.74 times as large as the intensity of solar radiation. 6 refs., 4 figs., 1 tab.

  5. Current-voltage characteristics of quantum-point contacts in the closed-channel regime: Transforming the bias voltage into an energy scale

    DEFF Research Database (Denmark)

    Gloos, K.; Utko, P.; Aagesen, M.

    2006-01-01

    We investigate the I(V) characteristics (current versus bias voltage) of side-gated quantum-point contacts, defined in GaAs/AlxGa1-xAs heterostructures. These point contacts are operated in the closed-channel regime, that is, at fixed gate voltages below zero-bias pinch-off for conductance. Our....... Such a built-in energy-voltage calibration allows us to distinguish between the different contributions to the electron transport across the pinched-off contact due to thermal activation or quantum tunneling. The first involves the height of the barrier, and the latter also its length. In the model that we...

  6. Temperature dependence and effects of series resistance on current and admittance measurements of Al/SnO2/p-Si MIS diode

    International Nuclear Information System (INIS)

    Altindal, S.; Tekeli, Z.; Karadeniz, S.; Sahingoez, R.

    2002-01-01

    Temperature dependency and the series resistance effect on I-V, C-V and G-V characteristics of Al/SnO 2 /p-Si MIS diode were investigated in the temperature range 150-350 K. The current-voltage (I-V) analysis in this temperature range gives the saturation current (10''-''9 - 10''-''5 A), the ideality factor (6-1.8), the barrier height Φ B (I-V) (0.3-0.65 eV) the density of interface states D it (8x10''1''3 - 1x10''1''3 eV''-''1cm''-''2) and the series resistance R s (500-100 Ω). The decreases with increasing temperature of density of interface states is the result of molecular restructuring and reordering at the metal-semiconductor interface. The value of series resistance 520 Ω was calculated from the admittance measurement at room temperature and enough high frequency (500 khz) when the diode is biased in strong accumulation region. The admittance frequency (C-V and G-V) measurement confirmed that the measured capacitance (C m ) and conductance (G m ) varies with applied voltage and frequency due to the presence of density of interface states in the MIS diode, interfacial insulator layer and enough high series resistance. Similar results have been observed on MIS type Schottky diodes

  7. Analysis of series resistance effects on forward I - V and C - V characteristics of mis type diodes

    International Nuclear Information System (INIS)

    Altindal, S.; Tekeli, Z.; Karadeniz, S.; Tugluoglu, N.; Ercan, I.

    2002-01-01

    In order to determine the series resistance R s , we have followed Lie et al., Cheung et al. and Kang et al., from the plot of I vs dV/dLn(I) which was linear curve over a wide range of current values at each temperature. The values of Rs were obtained from the slope of the linear parts of the curves and then the series resistance at each temperature has been evaluated at Ln(I) vs (V-IR s ) curves. The curves are linear over a wide range of voltage. The most reliable values of ideality factor n and reverse saturation current Is were then determined. In addition to role of series resistance on the C-V and G-V characteristics of diode have been investigated. Both C-V and G-V measurements show that the measured capacitance and conductance seriously varies with applied bias and frequency due to presence of R s . The density of interface states, barrier height and series resistance from the forward bias I-V characteristics using this method agrees very well with that obtained from the capacitance technique. It is clear that ignoring the series resistance (device with high series resistance) can lead to significant errors in the analysis of the I-V-T, C-V-f and G-V-f characteristics

  8. Low-cost, High Flexibility I-V Curve Tracer for Photovoltaic Modules

    DEFF Research Database (Denmark)

    Ibirriaga, Julen Joseba Maestro; Pena, Xabier Miquelez de Mendiluce; Opritescu, Adrian

    2010-01-01

    This work presents the design, construction and test of an in-door low cost, high flexibility I-V curve tracer for photovoltaic modules. The tracer is connected to a Xenon lamp based flashing solar simulator. The designed tracer is able to deal with the very fast changing irradiation conditions...

  9. Bianchi Type-I, V and VIo models in modified generalized scalar ...

    Indian Academy of Sciences (India)

    Keywords. Bianchi type; scalar–tensor theory; cosmological term; scalar field. ... We obtain exact solutions of the field equations in Bianchi Type-I, V and VIo space–times. The evolution of the scale factor ... Pramana – Journal of Physics | News.

  10. Characterisation of oral and i.v. glucose handling in truncally vagotomised subjects with pyloroplasty

    DEFF Research Database (Denmark)

    Plamboeck, Astrid; Veedfald, Simon; Deacon, Carolyn F

    2013-01-01

    =16) and matched controls (n=10) underwent 50 g-oral glucose tolerance test (OGTT)±vildagliptin, a DPP4 inhibitor (DPP4i) and isoglycaemic i.v. glucose infusion (IIGI), copying the OGTT without DPP4i. RESULTS: Isoglycaemia was obtained with 25±2 g glucose in vagotomised subjects and 18±2 g in controls...

  11. Ab initio I-V characteristics of short C-20 chains

    DEFF Research Database (Denmark)

    Roland, C.; Larade, B.; Taylor, Jeremy Philip

    2002-01-01

    We have calculated the I-V characteristics of short chains of C-20 molecular cages between Al and Au leads with an ab initio formalism. The results indicate that a linear chain of such molecules acts primarily as metallic nanowires. The transmission, however, depends sensitively both...

  12. The anchoring effect on the spin transport properties and I-V characteristics of pentacene molecular devices suspended between nickel electrodes.

    Science.gov (United States)

    Caliskan, S; Laref, A

    2014-07-14

    Spin-polarized transport properties are determined for pentacene sandwiched between Ni surface electrodes with various anchoring ligands. These calculations are carried out using spin density functional theory in tandem with a non-equilibrium Green's function technique. The presence of a Se atom at the edge of the pentacene molecule significantly modifies the transport properties of the device because Se has a different electronegativity than S. Our theoretical results clearly show a larger current for spin-up electrons than for spin-down electrons in the molecular junction that is attached asymmetrically across the Se linker at one side of the Ni electrodes (in an APL magnetic orientation). Moreover, this molecular junction exhibits pronounced NDR as the bias voltage is increased from 0.8 to 1.0 V. However, this novel NDR behavior is only detected in this promising pentacene molecular device. The NDR in the current-voltage (I-V) curve results from the narrowness of the density of states for the molecular states. The feasibility of controlling the TMR is also predicted in these molecular device nanostructures. Spin-dependent transmission calculations show that the sign and strength of the current-bias voltage characteristics and the TMR could be tailored for the organic molecule devices. These molecular junctions are joined symmetrically and asymmetrically between Ni metallic probes across the S and Se atoms (at the ends of the edges of the pentacene molecule). Our theoretical findings show that spin-valve phenomena can occur in these prototypical molecular junctions. The TMR and NDR results show that nanoscale junctions with spin valves could play a vital role in the production of novel functional molecular devices.

  13. Le projet français P.I.V.E.R.T.

    Directory of Open Access Journals (Sweden)

    Rous Jean-François

    2012-11-01

    Full Text Available P.I.V.E.R.T. is an ambitious project of development of the 3rd generation biorefinery by 2020. Conceived around a technological complex with strict environmental criteria (aiming at obtaining a label HQE, P.I.V.E.R.T. federates all the national and main roads lifeblood, of the sector (some international partnerships are also under development. The major objectives of the P.I.V.E.R.T. project are: a valorization of oilseeds, proteins and lignocellulosic plant in its entirety (approach ‘‘entire plants’’ ; an operation in closed circuit on the level of water and energy exchanges, the platform providing for its own needs, in a logic of industrial ecology ; collection and valorization of a significant part of the CO2 produced by the activities of the refinery. Two strategies will be developed jointly: on one hand the development of ‘‘platform’’ molecules entering the traditional circuits of chemistry, on the current markets with the renewable character, in addition, the development of new molecules having new properties, thus giving access to new markets. Thanks to the research and development realized by researchers dedicated to P.I.V.E.R.T., the industrial partners will have access to a capable structure to develop, and to test demonstrators preceding future industrial production units. Certain technological bricks could be tested in a large scale industrial platform dedicated to operational integration of innovations. The development of programming technologies of refineries will give to P.I.V.E.R.T. the means to develop new innovative processes and will give to the industrials the possibility of modeling their future production units.

  14. A model of electric breakdown in polycrystalline semiconductors with highly nonlinear I - V characteristics

    International Nuclear Information System (INIS)

    Yildirim, E.H.; Tanatar, B.; Canessa, E.

    1993-07-01

    A deterministic algorithm to study the nonlinear current-voltage characteristics of polycrystalline semiconductors, such as ZnO-based metal oxide varistors, under dc bias and at room temperature is developed based on the electrical properties of individual grain boundaries. Assuming a thermionic emission type mechanism between individual grains and a nonuniform distribution of barrier heights at grain boundaries, the set of nonlinear Kirchhoff equations that determines the macroscopic current across the specimen and the nonlinearity coefficient α is solved numerically. The applied voltage dependence of the barrier height is found to be crucial to obtain α values reaching ∼50, indicating high nonlinearity as required by potential commercial applications. (author). 20 refs, 3 figs

  15. Diagnostic method for photovoltaic systems based on light I-V measurements

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Sera, Dezso; Kerekes, Tamas

    2015-01-01

    , be it external, such as shading or soiling, or degradation or failure of the PV modules and balance-of-system components. This allows for performing preventive and/or reparative maintenance, thus minimizing further losses and costs. This article proposes a complete diagnostic method for detecting shading...... and analysis of the diagnostic parameters and logic was performed based on module level tests on standard crystalline silicon PV modules, and were optimized to detect even small partial shading and increase series-resistance losses. To demonstrate the practical application and operation of this method...

  16. Shunt resistance and saturation current determination in CdTe and CIGS solar cells. Part 2: application to experimental IV measurements and comparison with other methods

    Science.gov (United States)

    Rangel-Kuoppa, Victor-Tapio; Albor-Aguilera, María-de-Lourdes; Hérnandez-Vásquez, César; Flores-Márquez, José-Manuel; Jiménez-Olarte, Daniel; Sastré-Hernández, Jorge; González-Trujillo, Miguel-Ángel; Contreras-Puente, Gerardo-Silverio

    2018-04-01

    In this Part 2 of this series of articles, the procedure proposed in Part 1, namely a new parameter extraction technique of the shunt resistance (R sh ) and saturation current (I sat ) of a current-voltage (I-V) measurement of a solar cell, within the one-diode model, is applied to CdS-CdTe and CIGS-CdS solar cells. First, the Cheung method is used to obtain the series resistance (R s ) and the ideality factor n. Afterwards, procedures A and B proposed in Part 1 are used to obtain R sh and I sat . The procedure is compared with two other commonly used procedures. Better accuracy on the simulated I-V curves used with the parameters extracted by our method is obtained. Also, the integral percentage errors from the simulated I-V curves using the method proposed in this study are one order of magnitude smaller compared with the integral percentage errors using the other two methods.

  17. A mathematical model describing the glycemic response of diabetic patients to meal and i.v. infusion of insulin.

    Science.gov (United States)

    Fabietti, P G; Calabrese, G; Iorio, M; Bistoni, S; Brunetti, P; Sarti, E; Benedetti, M M

    2001-10-01

    Nine type 1 diabetic patients were studied for 24 hours. During this period they were given three calibrated meals. The glycemia was feedback-controlled by means of an artificial pancreas. The blood concentration of glucose and the infusion speed of the insulin were measured every minute. The experimental data referring to each of the three meals were used to estimate the parameters of a mathematical model suitable for describing the glycemic response of diabetic patients at meals and at the i.v. infusion of exogenous insulin. From the estimate a marked dispersion of the parameters was found, both interindividual and intraindividual. Nevertheless the models thus obtained seem to be usable for the synthesis of a feedback controller, especially in view of creating a portable artificial pancreas that now seems possible owing to the realization (so far experimental) of sufficiently reliable glucose concentration sensors.

  18. Minor human antibody response to a mouse and chimeric monoclonal antibody after a single i.v. infusion in ovarian carcinoma patients: a comparison of five assays

    NARCIS (Netherlands)

    Buist, M. R.; Kenemans, P.; van Kamp, G. J.; Haisma, H. J.

    1995-01-01

    The human anti-(mouse Ig) antibody (HAMA) response was measured in serum of 52 patients suspected of having ovarian carcinoma who had received an i.v. injection of either the murine monoclonal antibody (mAb) OV-TL 3 F(ab')2 (n = 28, 1 mg) or the chimeric mouse/human mAb MOv18 (cMOv18; n = 24, 3 mg).

  19. Negative resistance in I-V characteristics and 2D vortex dynamics in a-W/Si multilayer superconductors with periodic antidot arrays

    Energy Technology Data Exchange (ETDEWEB)

    Kurosu, Y.; Yokoyama, M.; Kuwasawa, Y.; Matsuda, S.; Nojima, T

    2003-05-01

    We have examined the vortex dynamics in W/Si multilayers with the arrays of antidots in the form of square and triangular lattices. In the measurements of I-V characteristics as a function of temperature T and magnetic field H, we find a specific feature that the V(I) curves coincide irrespective of T. Especially the V(I) curves with a negative slope are observed in the multilayer with triangular arrays.

  20. The i-V curve characteristics of burner-stabilized premixed flames: detailed and reduced models

    KAUST Repository

    Han, Jie

    2016-07-17

    The i-V curve describes the current drawn from a flame as a function of the voltage difference applied across the reaction zone. Since combustion diagnostics and flame control strategies based on electric fields depend on the amount of current drawn from flames, there is significant interest in modeling and understanding i-V curves. We implement and apply a detailed model for the simulation of the production and transport of ions and electrons in one-dimensional premixed flames. An analytical reduced model is developed based on the detailed one, and analytical expressions are used to gain insight into the characteristics of the i-Vcurve for various flame configurations. In order for the reduced model to capture the spatial distribution of the electric field accurately, the concept of a dead zone region, where voltage is constant, is introduced, and a suitable closure for the spatial extent of the dead zone is proposed and validated. The results from the reduced modeling framework are found to be in good agreement with those from the detailed simulations. The saturation voltage is found to depend significantly on the flame location relative to the electrodes, and on the sign of the voltage difference applied. Furthermore, at sub-saturation conditions, the current is shown to increase linearly or quadratically with the applied voltage, depending on the flame location. These limiting behaviors exhibited by the reduced model elucidate the features of i-V curves observed experimentally. The reduced model relies on the existence of a thin layer where charges are produced, corresponding to the reaction zone of a flame. Consequently, the analytical model we propose is not limited to the study of premixed flames, and may be applied easily to others configurations, e.g.~nonpremixed counterflow flames.

  1. YBCO single crystals I-V characteristics nonlinearity and Nelson-Kosterlitz jump

    International Nuclear Information System (INIS)

    Kuzmichev, N.D.; Vasyutin, M.A.; Golovashkin, A.I.

    2007-01-01

    Temperature dependences of I-V characteristics and voltage harmonics V n (T) (n = 2, 3, ...) have been investigated in magnetic fields up to 200 Oe for single crystals YBa 2 Cu 3 O 7-x . It was shown that V n (T) had asymmetric peak form with maximum at T* = 92.0 K. Amplitudes of V n (T) were decreased in magnetic fields. The results were explained on the base of the Berezinskii-Kosterlitz-Thouless (BKT) transition model. It was shown that T* coincided with the BKT transition temperature T BKT . The asymmetric peaks of V n (T) are a consequence of the Nelson-Kosterlitz jump

  2. Electrical characterization of polymer matrix — TiO2 filler composites through isothermal polarization / depolarization currents and I-V tests

    Science.gov (United States)

    Stavrakas, Ilias; Triantis, Dimos; Hloupis, George; Moutzouris, Konstantinos

    2014-04-01

    Specimens of polymer matrix — ceramic TiO2 filler composites were prepared. The contribution of the filler content on the electrical conductivity and energy storage properties of the samples was examined. I-V and Isothermal Polarization/Depolarization Current (IPC/IDC) measurements were conducted. Dc conductivity values directly calculated from the I-V curves exhibited excellent agreement with corresponding values derived from the IPC/IDC recordings. Standard models were employed for fitting the IPC/IDC data. In specific, the short and the very long depolarization times were fitted by use of power laws of different slopes, while the intermediate depolarization times were fitted as a sum of three exponential decays. The present study reveals a strong dependence of the depolarization and polarization processes, as well as of the dc conductivity, on the filler concentration.

  3. Current diffusion in a superconduting composite with a smeared I-V characteristic

    International Nuclear Information System (INIS)

    Keilin, V.E.; Romanovskii, V.R.

    1992-01-01

    Results are presented from numerical and analytical calculations of current injection into a superconducting composite of circular cross section with homogeneous properties throughout the cross section. A wire with an I-V characteristic approximated by an exponential dependence is examined. In the numerical solution, the joint occurrence of thermal and electromagnetic processes is taken into account. The calculations carried out for different current injection rates, parameters of the I-V characteristics, and heat transfer coefficients revealed: the existence of a characteristic limit current, below which the wire remains in a superconducting state after termination of current injection and above which the wire undergoes a transition to the normal state; this is somewhat below the cut-off current; the existence of a finite current at any small yet finite surface heat transfer coefficient. An analytical solution of the problem, based of the derived stability criterion, has made if possible to write an approximate relation between the limit currents and the initial parameters. Unlike previously reported results, this study takes into account the tolerable overheating of the wire, which depends on the depth of current flow, the specific heat of the wire, and its thermal and electrical conductivities

  4. Annealing effect on I-V characteristic of n-ZnO-p-InSe heterojunction

    Directory of Open Access Journals (Sweden)

    Kovalyuk Z. D.

    2015-12-01

    Full Text Available The article is devoted to studying of influence of vacuum low-temperature annealing on the electrical and photoelectric characteristics of n-ZnO-p-InSe heterostructure. Indium monoselenide (InSe is a semiconductor of the A3B6 group of layered compounds. The basic unit consists of two planes of metal atoms sandwiched between two planes of chalcogen atoms (Se-In-In-Se. The absence of dangling bonds on InSe cleaved surface makes it possible to use this semiconductor as a substrate for fabrication of heterostructures based on semiconductor materials with different symmetries and lattice spacings. Zinc oxide (ZnO is the most suitable material for window materials and solar cells buffer layers application due to its marvelous transparency in the range of visible region. InSe single crystals were grown by the Bridgman technique from a nonstoichiometric melt and characterized by a pronounced layered structure along the whole length of a sample. ZnO thin oxide film was formed on freshly cleaved van der Waals surface of InSe layered crystal. n-ZnO-p-InSe heterostructure was prepared by the method of high-frequency magnetron sputtering. Sensitivity spectral areas were identified by MDR-3 monochromator with a resolution of 2.6 nm/mm. The current-voltage characteristics of the n-ZnO-p-InSe heterostructures showed a clearly pronounced diode character. In the forward bias of the initial samples, the diode factor had the value 3.7 at room temperature. It is shown that vacuum low-temperature annealing reduces shunt currents of the heterojunction, which is reflected in the decrease in the values of n from 3.7 to 2.7.

  5. Investigation of diode parameters using I-V and C-V characteristics of In/SiO{sub 2}/p-Si (MIS) Schottky diodes

    Energy Technology Data Exchange (ETDEWEB)

    Yueksel, O.F. [Department of Physics, Faculty of Arts and Science, Selcuk University, Kampus, Konya 42075 (Turkey)], E-mail: fyuksel@selcuk.edu.tr; Selcuk, A.B.; Ocak, S.B. [PK, 14 Etlik, Ankara (Turkey)

    2008-08-01

    A study on interface states density distribution and characteristic parameters of the In/SiO{sub 2}/p-Si (MIS) capacitor has been made. The thickness of the SiO{sub 2} film obtained from the measurement of the corrected capacitance in the strong accumulation region for MIS Schottky diodes was 220 A. The diode parameters from the forward bias I-V characteristics such as ideality factor, series resistance and barrier heights were found to be 1.75, 106-112 {omega} and 0.592 eV, respectively. The energy distribution of the interface state density D{sub it} was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. The interface state density obtained using the I-V characteristics had an exponential growth, with bias towards the top of the valance band, from 9.44x10{sup 13} eV{sup -1} cm{sup -2} in 0.329-E{sub v} eV to 1.11x10{sup 13} eV{sup -1} cm{sup -2} in 0.527-E{sub v} eV at room temperature. Furthermore, the values of interface state density D{sub it} obtained by the Hill-Coleman method from the C-V characteristics range from 52.9x10{sup 13} to 1.11x10{sup 13} eV{sup -1} cm{sup -2} at a frequency range of 30kHz-1 MHz. These values of D{sub it} and R{sub s} were responsible for the non-ideal behaviour of I-V and C-V characteristics.

  6. Scanning transient current study of the I-V stabilization phenomena in silicon detectors irradiated by fast neutrons

    International Nuclear Information System (INIS)

    Eremin, V.; Verbitskaya, E.; Sidorov, A.; Fretwurst, E.; Lindstrom, G.

    1996-03-01

    Investigation of the I-V stabilization phenomena in neutron irradiated silicon detectors has been carried out using scanning transient current technique (STCT) on non-irradiated PP + -p-n + detectors. The PP + -p-n + detectors were used to simulate the PP + -n-n + detectors irradiated beyond the space charge sign inversion (SCSI). Two mechanisms partially responsible for the I- V stabilization have been identified

  7. Anomalous I-V curve for mono-atomic carbon chains

    International Nuclear Information System (INIS)

    Song Bo; Fang Haiping; Sanvito, Stefano

    2010-01-01

    The electronic transport properties of mono-atomic carbon chains were studied theoretically using a combination of density functional theory and the non-equilibrium Green's functions method. The I-V curves for the chains composed of an even number of atoms and attached to gold electrodes through sulfur exhibit two plateaus where the current becomes bias independent. In contrast, when the number of carbon atoms in the chain is odd, the electric current simply increases monotonically with bias. This peculiar behavior is attributed to dimerization of the chains, directly resulting from their one-dimensional nature. The finding is expected to be helpful in designing molecular devices, such as carbon-chain-based transistors and sensors, for nanoscale and biological applications.

  8. Single i.v. ketamine augmentation of newly initiated escitalopram for major depression: results from a randomized, placebo-controlled 4-week study.

    Science.gov (United States)

    Hu, Y-D; Xiang, Y-T; Fang, J-X; Zu, S; Sha, S; Shi, H; Ungvari, G S; Correll, C U; Chiu, H F K; Xue, Y; Tian, T-F; Wu, A-S; Ma, X; Wang, G

    2016-02-01

    While oral antidepressants reach efficacy after weeks, single-dose intravenous (i.v.) ketamine has rapid, yet time-limited antidepressant effects. We aimed to determine the efficacy and safety of single-dose i.v. ketamine augmentation of escitalopram in major depressive disorder (MDD). Thirty outpatients with severe MDD (17-item Hamilton Rating Scale for Depression total score ⩾ 24) were randomized to 4 weeks double-blind treatment with escitalopram 10 mg/day+single-dose i.v. ketamine (0.5 mg/kg over 40 min) or escitalopram 10 mg/day + placebo (0.9% i.v. saline). Depressive symptoms were measured using the Montgomery-Asberg Depression Rating Scale (MADRS) and the Quick Inventory of Depressive Symptomatology - Self-Report (QIDS-SR). Suicidal ideation was evaluated with the QIDS-SR item 12. Adverse psychopathological effects were measured with the Brief Psychiatric Rating Scale (BPRS)-positive symptoms, Young Mania Rating Scale (YMRS) and Clinician Administered Dissociative States Scale (CADSS). Patients were assessed at baseline, 1, 2, 4, 24 and 72 h and 7, 14, 21 and 28 days. Time to response (⩾ 50% MADRS score reduction) was the primary outcome. By 4 weeks, more escitalopram + ketamine-treated than escitalopram + placebo-treated patients responded (92.3% v. 57.1%, p = 0.04) and remitted (76.9% v. 14.3%, p = 0.001), with significantly shorter time to response [hazard ratio (HR) 0.04, 95% confidence interval (CI) 0.01-0.22, p escitalopram + placebo, escitalopram + ketamine was associated with significantly lower MADRS scores from 2 h to 2 weeks [(peak = 3 days-2 weeks; effect size (ES) = 1.08-1.18)], QIDS-SR scores from 2 h to 2 weeks (maximum ES = 1.27), and QIDS-SR suicidality from 2 to 72 h (maximum ES = 2.24). Only YMRS scores increased significantly with ketamine augmentation (1 and 2 h), without significant BPRS or CADSS elevation. Single-dose i.v. ketamine augmentation of escitalopram was safe and effective in severe MDD, holding promise for speeding up

  9. The changes of capacitance-loss and current-voltage characteristics of LaMnO3+δ/SrTiO3:Nb heterojunctions exposed to ambient air

    International Nuclear Information System (INIS)

    Cui Yimin; Wang Rongming

    2010-01-01

    Effects of moisture absorption on capacitance-loss and current-voltage characteristics of LaMnO 3+δ /SrTiO 3 :Nb heterojunction had been investigated after the heterojunctions were exposed to ambient air. The moisture-absorption-induced increases in loss tangent and breakdown voltage were observed, whereas no changes were found on capacitance and diffusion voltage. These results were discussed by the decrease of oxygen ions in LaMnO 3+δ and the generation of hydroxide ions at grain boundaries. This work will favor both electronic transport analysis and future device applications.

  10. Charge carrier transport in Cu(In,Ga)Se2 thin-film solar-cells studied by electron beam induced current and temperature and illumination dependent current voltage analysis

    International Nuclear Information System (INIS)

    Nichterwitz, Melanie

    2012-01-01

    This work contributes to the understanding of generation dependent charge-carrier transport properties in Cu(In,Ga)Se 2 (CIGSe)/ CdS/ ZnO solar cells and a consistent model for the electronic band diagram of the heterojunction region of the device is developed. Cross section electron-beam induced current (EBIC) and temperature and illumination dependent current voltage (IV) measurements are performed on CIGSe solar cells with varying absorber layer compositions and CdS thickness. For a better understanding of possibilities and limitations of EBIC measurements applied on CIGSe solar cells, detailed numerical simulations of cross section EBIC profiles for varying electron beam and solar cell parameters are performed and compared to profiles obtained from an analytical description. Especially the effects of high injection conditions are considered. Even though the collection function of the solar cell is not independent of the generation function of the electron beam, the local electron diffusion length in CIGSe can still be extracted. Grain specific values ranging from (480±70) nm to (2.3±0.2) μm are determined for a CuInSe 2 absorber layer and a value of (2.8±0.3) μm for CIGSe with a Ga-content of 0.3. There are several models discussed in literature to explain generation dependent charge carrier transport, all assuming a high acceptor density either located in the CIGSe layer close to the CIGSe/CdS interface (p + layer), within the CdS layer or at the CdS/ZnO interface. In all models, a change in charge carrier collection properties is caused by a generation dependent occupation probability of the acceptor type defect state and the resulting potential distribution throughout the device. Numerical simulations of EBIC and IV data are performed with parameters according to these models. The model that explains the experimental data best is that of a p + layer at the CIGSe/CdS interface and acceptor type defect states at the CdS/ZnO interface. The p + layer leads

  11. Determination of the faecal excretion of labelled bile salts after i.v. administration of 14 C-cholic

    International Nuclear Information System (INIS)

    Andersson, H.; Filipsson, S.; Hulten, L.

    1978-01-01

    By measuring total faecal radioactivity, correlated to 24-hour enterohepatic circulation following i.v. administration of 14 C-cholic acid, bile salt malabsorption was evaluated before and/or after surgery in 80 patients with Crohn's disease localized to the ileum and/or the colon and the results related to the length of ileum diseased or resected. Before operation bile salt malabsorption was observed only in patients with inflammation of the terminal ileum, but no significant correlation was found between bile salt excretion and the extent of ileal disease. In patients subjected to ileal resection with sacrifice of the ileocaecal valve, bile salt malabsorption correlated strongly to the length of ileum resected. This correlation was about the same in ileostomy patients and in patients subjected to restorative operation. It is concluded that determination of 14 C in faeces is a more sensitive test than the Schilling test and the faecal fat excretion test in reflecting ileal dysfunction, at least in patients with ileal resections. (Auth.)

  12. Modelling of current-voltage characteristics of infrared photo-detectors based on type – II InAs/GaSb super-lattice diodes with unipolar blocking layers

    Directory of Open Access Journals (Sweden)

    Vishnu Gopal

    2015-09-01

    Full Text Available It is shown that current-voltage characteristics of infrared photo-detectors based on type-II InAs/GaSb super-lattices with uni-polar blocking layers can be modelled similar to a junction diode with a finite series resistance on account of blocking barriers. As an example this paper presents the results of a study of current-voltage characteristics of a type II InAs/GaSb super-lattice diode with PbIbN architecture using a recently proposed [J. Appl. Phys. 116, 084502 (2014] method for modelling of illuminated photovoltaic detectors. The thermal diffusion, generation – recombination (g-r, and ohmic currents are found as principal components besides a component of photocurrent due to background illumination. The experimentally observed reverse bias diode current in excess of thermal current (diffusion + g-r, photo-current and ohmic shunt current is reported to be best described by an exponential function of the type, Iexcess = Ir0 + K1exp(K2 V, where Ir0, K1 and K2 are fitting parameters and V is the applied bias voltage. The present investigations suggest that the exponential growth of excess current with the applied bias voltage may be taking place along the localized regions in the diode. These localized regions are the shunt resistance paths on account of the surface leakage currents and/or defects and dislocations in the base of the diode.

  13. Quantitative analysis of charge trapping and classification of sub-gap states in MoS2 TFT by pulse I-V method

    Science.gov (United States)

    Park, Junghak; Hur, Ji-Hyun; Jeon, Sanghun

    2018-04-01

    The threshold voltage instabilities and huge hysteresis of MoS2 thin film transistors (TFTs) have raised concerns about their practical applicability in next-generation switching devices. These behaviors are associated with charge trapping, which stems from tunneling to the adjacent trap site, interfacial redox reaction and interface and/or bulk trap states. In this report, we present quantitative analysis on the electron charge trapping mechanism of MoS2 TFT by fast pulse I-V method and the space charge limited current (SCLC) measurement. By adopting the fast pulse I-V method, we were able to obtain effective mobility. In addition, the origin of the trap states was identified by disassembling the sub-gap states into interface trap and bulk trap states by simple extraction analysis. These measurement methods and analyses enable not only quantitative extraction of various traps but also an understanding of the charge transport mechanism in MoS2 TFTs. The fast I-V data and SCLC data obtained under various measurement temperatures and ambient show that electron transport to neighboring trap sites by tunneling is the main charge trapping mechanism in thin-MoS2 TFTs. This implies that interfacial traps account for most of the total sub-gap states while the bulk trap contribution is negligible, at approximately 0.40% and 0.26% in air and vacuum ambient, respectively. Thus, control of the interface trap states is crucial to further improve the performance of devices with thin channels.

  14. A general modeling method for I-V characteristics of geometrically and electrically configured photovoltaic arrays

    International Nuclear Information System (INIS)

    Liu Guangyu; Nguang, Sing Kiong; Partridge, Ashton

    2011-01-01

    Highlights: → A novel and general method is proposed for modeling PV arrays or modules. → A robust algorithm is used for the first time to improve the convergence to solution. → Auxiliary functions in other general methods are not compulsory in our method. → It is novel that geometric configuration is also incorporated. → A case study is performed to show the approach's advantages and unique features. - Abstract: A general method for modeling typical photovoltaic (PV) arrays and modules is proposed to find the exact current and voltage relationship of PV arrays or modules of geometrically and electrically different configurations. Nonlinear characteristic equations of electrical devices in solar array or module systems are numerically constructed without adding any virtual electrical components. Then, a robust damped Newton method is used to find exact I-V relationship of these general nonlinear equations, where the convergence is guaranteed. The model can deal with different mismatch effects such as different configurations of bypass diodes, and partial shading. Geometry coordinates of PV components are also considered to facilitate the modeling of the actual physical configuration. Simulation of a PV array with 48 modules, partially shaded by a concrete structure, is performed to verify the effectiveness and advantages of the proposed method.

  15. Hepatic and muscle clearance of physostigmine in the rat after i.v. administration

    International Nuclear Information System (INIS)

    Somani, S.M.; Unni, L.K.

    1986-01-01

    This study presents a method to calculate the extraction ratio (ER) from in vivo time course of liver metabolism using the physiological and pharmacokinetic parameters such as plasma flow rate, partition coefficient of drug between tissue and plasma and the elimination rate constant from tissues. Rats were administered 3 H-physostigmine (Phy), 100 μg/kg i.v.; and were sacrificed at various times. Tissues were removed and Phy and its metabolites were determined by HPLC. Half-life of Phy in liver and muscle was 24 and 20 min, respectively. ER of Phy in liver was .71 which showed a slight decrease at 10 min. Muscle ER was found to be .347 up to 5 min. Hepatic clearance was calculated to be 23.08 ml/min/kg (34.9% of systemic clearance) and the intrinsic clearance was 83.73 ml/min/kg which indicates that the changes in blood flow to the liver can cause a variation in the systematic clearance. Percentage dose of Phy retained in muscle was maximum and the clearance was 5.2 ml/min/kg suggesting that muscle might be acting as a storage depot for Phy prolonging the pharmacological effects. About 30-40% of radioactivity in the liver could not be washed off by 10% TCA or organic solvents indicating the irreversible binding of drug or metabolite to liver macromolecule

  16. Statistically Modeling I-V Characteristics of CNT-FET with LASSO

    Science.gov (United States)

    Ma, Dongsheng; Ye, Zuochang; Wang, Yan

    2017-08-01

    With the advent of internet of things (IOT), the need for studying new material and devices for various applications is increasing. Traditionally we build compact models for transistors on the basis of physics. But physical models are expensive and need a very long time to adjust for non-ideal effects. As the vision for the application of many novel devices is not certain or the manufacture process is not mature, deriving generalized accurate physical models for such devices is very strenuous, whereas statistical modeling is becoming a potential method because of its data oriented property and fast implementation. In this paper, one classical statistical regression method, LASSO, is used to model the I-V characteristics of CNT-FET and a pseudo-PMOS inverter simulation based on the trained model is implemented in Cadence. The normalized relative mean square prediction error of the trained model versus experiment sample data and the simulation results show that the model is acceptable for digital circuit static simulation. And such modeling methodology can extend to general devices.

  17. Diagnosing feline infectious peritonitis using the Sysmex XT-2000iV based on frozen supernatants from cavitary effusions.

    Science.gov (United States)

    Stranieri, Angelica; Paltrinieri, Saverio; Giordano, Alessia

    2017-05-01

    The delta total nucleated cells (ΔTNC) measurement with the Sysmex XT-2000iV (Sysmex Europe, Norderstedt, Germany) has high diagnostic accuracy on effusions in feline infectious peritonitis (FIP) cases, but the test can be performed only on fresh samples. We evaluated whether supernatants from effusions retain the ability to induce cell clumping and assessed the diagnostic accuracy of this modified ΔTNC method. Effusions were collected from FIP cats ( n = 19) and from cats with other diseases ( n = 15). ΔTNC was measured on fresh samples and on frozen-thawed supernatants after the addition of feline blood at 1:10 dilution. Diagnostic accuracy was assessed at the cutoffs of suggestive of FIP (ΔTNC = 1.7) and consistent with FIP (ΔTNC = 3.4). The influence of the protein content, number of added cells, and magnitude of dilution were also investigated. Specificity and positive predictive value were 100% for both the methods. Sensitivity and negative predictive value were higher for the modified ΔTNC (84.2% and 83.3%, respectively, at the cutoff of 1.7; 78.9% and 78.9%, respectively, at the cutoff of 3.4) than for the ΔTNC on fresh samples (78.6% and 81.3%, respectively, at the cutoff of 1.7; 57.1% and 68.4%, respectively, at the cutoff of 3.4). Protein content, total cell count of the added blood, and magnitude of dilutions did not influence the results. Supernatants of frozen effusions from FIP cats retain the ability to induce cell clumping, thus the modified ΔTNC measurement is a reliable tool to diagnose FIP on samples that cannot be analyzed immediately.

  18. Determination of PV Generator I-V/P-V Characteristic Curves Using a DC-DC Converter Controlled by a Virtual Instrument

    Directory of Open Access Journals (Sweden)

    E. Durán

    2012-01-01

    Full Text Available A versatile measurement system for systematic testing and measurement of the evolution of the I-V characteristic curves of photovoltaic panels or arrays (PV generators is proposed in this paper. The measurement system uses a circuit solution based on DC-DC converters that involves several advantages relative to traditional methods: simple structure, scalability, fast response, and low cost. The measurement of the desired characteristics of PV generators includes high speed of response and high fidelity. The prototype system built is governed by a microcontroller, and experimental results prove the proposed measurement system useful. A virtual instrument (VI was developed for full system control from a computer. The developed system enables monitoring the suitable operation of a PV generator in real time, since it allows comparing its actual curves with those provided by the manufacturer.

  19. Preparation of i.v. 99mTc radiopharmaceuticals from spent moly 99Mo

    International Nuclear Information System (INIS)

    Noronha, O.P.D.

    1998-01-01

    Full text: Expiry dating is an important quality assurance precept in (radio) pharmacy. There are occasions when for the sake of patient service one may be forced to continue using an over aged source of 99 Mo to generate 99m Tc beyond 7d, especially when there is short/no supply of 99 Mo, (In the early days the expiry date was 3 d or 3 extractions, whichever one was earlier). With the passage of time a few physico-chemical changes (apart from decay) do occur in the 99 Mo/ 99m Tc milieu. The cocktail also begins to contain traces of carried over MEK which is subjected to strong β-, γ irradiation. These impurity (in trace amounts) is soluble in MEK and even, to an extent, in aqueous media. Furthermore, the concentrated impurity tends to seemingly increase in the bulk 99m TcO 4 - since one is compelled to leach TcO 4 - in lower volume of saline. On many occasions we have been constrained to extend the use of 99 Mo beyond 7 - 14 d. Adequate activities were obtained by pooling the previous week's lot of 99 Mo with the current over aged lot. On a few occasions over the past 26 years we have used 99 Mo much beyond 14 d and 2 - 3 occasions for 26 - 28 d (i.e. >10 t 1 /2 of 99 Mo). On each of these occasions the purity of 99m TcO- 4 was ascertained by pharmacopoeial procedures. It was found that despite depleting activities, the purity was not compromised and the trace impurities, even if present, did not cause any interference. We have profitably utilised the bulk TcO- 4 to formulate a variety of i.v. dosage forms of 99m Tc radiodiagnostics. The following strategy was adopted for the patient services - the agents requiring larger activity levels/patients dose were made available in the earlier period, the other during the latter half. It is concluded that pure 99m TcO- 4 can be obtained over the entire useful life-period of 99 Mo, even > 10t l/2

  20. Preparation of ZnO film on p-Si and I-V characteristics of p-Si/n-ZnO

    Directory of Open Access Journals (Sweden)

    Shampa Mondal

    2012-01-01

    Full Text Available Zinc oxide (ZnO thin films were deposited on p-silicon (Si substrate from ammonium zincate bath following a chemical dipping technique called SILAR. Films in the thickness range 0.5-4.5 µm could be prepared by varying the number of dipping for a fixed concentration (0.125 M of zincate bath and fixed pH (11.00-11.10. Higher values of dipping produced nonadherent and poor quality films. Structural characterization by X-ray diffraction (XRD indicates the formation of polycrystalline single phase ZnO with strong c-axis orientation. The structural characteristics of the films were found to be a sensitive function of film thickness. The degree of orientation was found to be a function of film thickness and a maximum was found at around 2.2 µm. Scanning electron microscopy (SEM reveals the formation of sub-micrometer crystallites on silicon substrate. The coverage of crystallites (grains on substrate surface increases with number of dipping. Dense film containing grains distributed throughout the surface is obtained at large thicknesses. The ohmic nature of silver (Ag on ZnO and Aluminum (Al on p-Si was confirmed by I-V measurements. I-V characteristic of the p-Si/n-ZnO heterojunction was studied and rectification was observed. The maximum value of forward to reverse current ratio was ~15 at 3.0 V.

  1. Preparation of ZnO film on p-Si and I-V characteristics of p-Si/n-ZnO

    Directory of Open Access Journals (Sweden)

    Shampa Mondal

    2013-02-01

    Full Text Available Zinc oxide (ZnO thin films were deposited on p-silicon (Si substrate from ammonium zincate bath following a chemical dipping technique called SILAR. Films in the thickness range 0.5-4.5 µm could be prepared by varying the number of dipping for a fixed concentration (0.125 M of zincate bath and fixed pH (11.00-11.10. Higher values of dipping produced nonadherent and poor quality films. Structural characterization by X-ray diffraction (XRD indicates the formation of polycrystalline single phase ZnO with strong c-axis orientation. The structural characteristics of the films were found to be a sensitive function of film thickness. The degree of orientation was found to be a function of film thickness and a maximum was found at around 2.2 µm. Scanning electron microscopy (SEM reveals the formation of sub-micrometer crystallites on silicon substrate. The coverage of crystallites (grains on substrate surface increases with number of dipping. Dense film containing grains distributed throughout the surface is obtained at large thicknesses. The ohmic nature of silver (Ag on ZnO and Aluminum (Al on p-Si was confirmed by I-V measurements. I-V characteristic of the p-Si/n-ZnO heterojunction was studied and rectification was observed. The maximum value of forward to reverse current ratio was ~15 at 3.0 V.

  2. Construction of Tungsten Halogen, Pulsed LED, and Combined Tungsten Halogen-LED Solar Simulators for Solar Cell I-V Characterization and Electrical Parameters Determination

    Directory of Open Access Journals (Sweden)

    Anon Namin

    2012-01-01

    Full Text Available I-V characterization of solar cells is generally done under natural sunlight or solar simulators operating in either a continuous mode or a pulse mode. Simulators are classified on three features of irradiance, namely, spectral match with respect to air mass 1.5, spatial uniformity, and temporal stability. Commercial solar simulators use Xenon lamps and halogen lamps, whereas LED-based solar simulators are being developed. In this work, we build and test seven simulators for solar cell characterization, namely, one tungsten halogen simulator, four monochromatic (red, green, blue, and white LED simulators, one multicolor LED simulator, and one tungsten halogen-blue LED simulator. The seven simulators provide testing at nonstandard test condition. High irradiance from simulators is obtained by employing elevated supply voltage to tungsten halogen lamps and high pulsing voltages to LEDs. This new approach leads to higher irradiance not previously obtained from tungsten halogen lamps and LEDs. From I-V curves, electrical parameters of solar cell are made and corrected based on methods recommended in the IEC 60891 Standards. Corrected values obtained from non-STC measurements are in good agreement with those obtained from Class AAA solar simulator.

  3. Actions of Agonists, Fipronil and Ivermectin on the Predominant In Vivo Splice and Edit Variant (RDLbd, I/V) of the Drosophila GABA Receptor Expressed in Xenopus laevis Oocytes

    Science.gov (United States)

    Suwanmanee, Siros; Buckingham, Steven David; Biggin, Philip; Sattelle, David

    2014-01-01

    Ionotropic GABA receptors are the targets for several classes of insecticides. One of the most widely-studied insect GABA receptors is RDL (resistance to dieldrin), originally isolated from Drosophila melanogaster. RDL undergoes alternative splicing and RNA editing, which influence the potency of GABA. Most work has focussed on minority isoforms. Here, we report the first characterisation of the predominant native splice variant and RNA edit, combining functional characterisation with molecular modelling of the agonist-binding region. The relative order of agonist potency is GABA> muscimol> TACA> β-alanine. The I/V edit does not alter the potency of GABA compared to RDLbd. Docking calculations suggest that these agonists bind and activate RDLbdI/V through a similar binding mode. TACA and β-alanine are predicted to bind with lower affinity than GABA, potentially explaining their lower potency, whereas the lower potency of muscimol and isoguvacine cannot be explained structurally from the docking calculations. The A301S (resistance to dieldrin) mutation reduced the potency of antagonists picrotoxin, fipronil and pyrafluprole but the I/V edit had no measurable effect. Ivermectin suppressed responses to GABA of RDLbdI/V, RDLbd and RDLbdI/VA301S. The dieldrin resistant variant also showed reduced sensitivity to Ivermectin. This study of a highly abundant insect GABA receptor isoform will help the design of new insecticides. PMID:24823815

  4. The pharmacokinetics and safety of twice daily i.v. BU during conditioning in pediatric allo-SCT recipients.

    Science.gov (United States)

    Le Gall, J B; Milone, M C; Waxman, I M; Shaw, L M; Harrison, L; Duffy, D; van de Ven, C; Militano, O; Geyer, M B; Morris, E; Bhatia, M; Satwani, P; George, D; Garvin, J H; Bradley, M B; Schwartz, J; Baxter-Lowe, L A; Cairo, M S

    2013-01-01

    Intravenous BU divided four times daily (q6 h) has been shown to be safe and effective in pediatric allo-SCT recipients. Though less frequent dosing is desirable, pharmacokinetic (PK) data on twice daily (q12 h) i.v. BU administration in pediatric allo-SCT recipients is limited. We prospectively examined the PK results in a cohort of pediatric allo-SCT recipients receiving i.v. BU q12 h as part of conditioning before allo-SCT. BU levels were obtained after the first dose of conditioning. PK parameter analysis (n=49) yielded the following 95% confidence intervals (CI₉₅): weight-normalized volume of distribution: 0.65-0.73 L/kg; t(1/2): 122-147 min; weight-normalized clearance (CL(n)): 3.4-4.3 mL/min/kg; and area under the curve: 1835-2180 mmol × min/L. From these results, a steady state concentration was calculated with CI₉₅ between 628-746 ng/mL. Comparison between recipients ≤4 vs >4 years old revealed significant differences in t(1/2) (mean: 115 vs 146 min, P=0.008) and CL(n) (mean: 4.4 vs 3.5 mL/min/kg, P=0.038). Intravenous BU q12 h had a comparable PK to i.v. BU q6 h PK seen in the literature, and in pediatric allo-SCT recipients, is a feasible, attractive alternative to i.v. q6h dosing.

  5. On the I-V characteristic in the non-linear tenary mixture model for polycrystalline semiconductors

    International Nuclear Information System (INIS)

    Nguyen Van Lien; Nguyen Hoai Nam

    2000-08-01

    A simple expression for the voltage dependence of grain-boundary potential barrier heights is proposed and the Effective Medium Approximation is extended for calculating the I-V characteristic in tenary mixtures of highly non-linear circuit elements. Numerical calculations are performed for the case of polycrystalline semiconductors, such as ZnO-based varistors, where the thermoionic emission is believed to be the dominant mechanism for the electric conduction across double Schottky barriers at room temperature. (author)

  6. Practice patterns for the use of iodinated i.v. contrast media for pediatric CT studies: a survey of the Society for Pediatric Radiology.

    Science.gov (United States)

    Callahan, Michael J; Servaes, Sabah; Lee, Edward Y; Towbin, Alexander J; Westra, Sjirk J; Frush, Donald P

    2014-04-01

    There are limited data available on the use of i.v. contrast media for CT studies in the pediatric population. The purpose of this study is to determine the practice patterns of i.v. contrast media usage for pediatric CT by members of the Society for Pediatric Radiology (SPR). SPR members were surveyed regarding the use of i.v. contrast media for pediatric CT studies. Questions pertained to information required before administering i.v. contrast media, types of central catheters for injecting i.v. contrast media, injection rates based on angiocatheter size and study type, and management of i.v. contrast media extravasation. The response rate of 6% (88/1545) represented practice patterns of 26% (401/1545) of the SPR membership. Most respondents thought the following clinical information was mandatory before i.v. contrast media administration: allergy to i.v. contrast media (97%), renal insufficiency (97%), current metformin use (72%), significant allergies (61%), diabetes (54%), and asthma (52%). Most administered i.v. contrast media through nonimplanted central venous catheters (78%), implanted venous ports (78%), and peripherally inserted central catheters (72%). The most common maximum i.v. contrast media injection rates were 5.0 mL/s or greater for a 16-gauge angiocatheter, 4.0 mL/s for an 18-gauge angiocatheter, 3.0 mL/s for a 20-gauge angiocatheter, and 2.0 mL/s for a 22-gauge angiocatheter. For soft-tissue extravasation of i.v. contrast media, 95% elevate the affected extremity, 76% use ice, and 45% use heat. The results of this survey illustrate the collective opinion of a subset of SPR members relating to the use of i.v. contrast media in pediatric CT, providing guidelines for clinical histories needed before i.v. contrast media, maximum i.v. contrast injection rates for standard angiocatheters, contrast media injection rates for specific CT studies, and management of i.v. contrast media soft-tissue extravasation.

  7. An accurate mobility model for the I-V characteristics of n-channel enhancement-mode MOSFETs with single-channel boron implantation

    International Nuclear Information System (INIS)

    Chingyuan Wu; Yeongwen Daih

    1985-01-01

    In this paper an analytical mobility model is developed for the I-V characteristics of n-channel enhancement-mode MOSFETs, in which the effects of the two-dimensional electric fields in the surface inversion channel and the parasitic resistances due to contact and interconnection are included. Most importantly, the developed mobility model easily takes the device structure and process into consideration. In order to demonstrate the capabilities of the developed model, the structure- and process-oriented parameters in the present mobility model are calculated explicitly for an n-channel enhancement-mode MOSFET with single-channel boron implantation. Moreover, n-channel MOSFETs with different channel lengths fabricated in a production line by using a set of test keys have been characterized and the measured mobilities have been compared to the model. Excellent agreement has been obtained for all ranges of the fabricated channel lengths, which strongly support the accuracy of the model. (author)

  8. I.V.P. Reisid ja VS Angiras nüüd ühe mütsi all / Irina Kiviselg

    Index Scriptorium Estoniae

    Kiviselg, Irina, 1961-

    2004-01-01

    Ilmunud ka: Severnoje Poberezhje, 14. apr. 2004, lk. 4. Ida-Virumaa bussiettevõte I.V.P. Reisid vahetas omanikku, muutudes ettevõtte Kris Kütus üheks osaks. VS Angirase ja I.V.P. Reiside omanik on Boriss Dantshenko

  9. Change of I-V characteristics of SiC diodes upon reactor irradiation; Modification des caracteristiques I-V de jonctions p-n au SiC du fait d'une irradiation dans un reacteur; Izmeneniya kharakteristik I-V vyrashchennogo v SiC perekhoda tipa p-n posle oblucheniya ego v reaktore; Modificaciones que sufren por irradiacion en un reactor las caracteristicas I-V de uniones p-n en SiC

    Energy Technology Data Exchange (ETDEWEB)

    Heerschap, M; De Coninck, R [Solid State Physics Dept., SCK-CEN, Mol (Belgium)

    1962-04-15

    In search for semiconductors, which can be used in high-flux reactors in order to measure flux distributions, we irradiated SiC p-n junctions in the Belgium BR-1 reactor. Two types of SiC-diodes of different origin have been irradiated. These junctions are grown in the Lely-furnace. The change in forward and reverse characteristics have been measured during and after irradiation up to temperatures of 150{sup o}C, while measurements up to a temperature of 500{sup o}C are in progress. It has been found that one type resists BR-1 neutrons up to an integrated flux of 10{sup 15} n/cm{sup 2}, while the other resists irradiation up to a flux of 10{sup 17} n/cm{sup 2}. The changes in characteristics are given as well as the result of some annealing experiments. (author) [French] En recherchant des semi-conducteurs pouvant servir a mesurer les distributions de flux dans les reacteurs a haut flux de neutrons, les auteurs ont irradie des jonctions p-n au SiC dans le reacteur belge BR-1. Deux types de diodes a SiC d'origines differentes ont ete ainsi irradies. Les jonctions en question sont preparees par etirage dans le four Lely. Les auteurs ont mesure les modifications subies par les caracteristiques I-V apres et pendant l'irradiation a des temperatures allant jusqu'a 150{sup o}C; ils poursuivent leurs mesures dans la gamme des temperatures allant de 150{sup o}C a 500{sup o}C. Us ont constate que l'un des types de diode a SiC resiste aux neutrons du reacteur BR-1 jusqu'a 10{sup 15} n/cm{sup 2}, tandis que l'autre type resiste a l'irradiation jusqu'a 10{sup 17} n/cm{sup 2}. Les auteurs indiquent les modifications subies par les caracteristiques, ainsi que le resultat de certaines experiences de recuit. (author) [Spanish] Los autores estan tratando de encontrar semiconductores con los que sea posible medir distribuciones de flujo en reactores de flujo elevado, y con este fin irradiaron uniones p-n del SiC en el reactor BR-1 de Belgica. Irradiaron dos tipos de diodos de SiC de

  10. Investigation on I-V for Different Heating Temperatures of Nanocomposited MEH-PPV:CNTs Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    M. S. P. Sarah

    2012-01-01

    Full Text Available This paper discussed the effect of different thermal evaporation treatments for nanocomposited MEH-PPV:CNTs thin films towards the performance of organic solar cells. The configuration of the organic solar cells is ITO/MEH-PPV:CNTs/Au. The heating temperature was varied from, as deposited, 50°C, 75°C, and 100°C. From the results, we observed that the efficiency increase slightly before decreasing back at 100°C. The highest efficiency was solar cells heated at 75°C with efficiency 0.001% which is supported by the I-V characteristics and also by the absorption spectra.

  11. Characterization and Modeling I(V of the Gate Schottky Structures HEMTs Ni/Au/AlInN/GaN

    Directory of Open Access Journals (Sweden)

    N. Benyahya

    2014-05-01

    Full Text Available In this paper, we have studied the Schottky contact of Ni/Au/AlInN/GaN HEMTs. The current–voltage Igs (Vgs of Ni/Au/AlInN/GaN structures were investigated at room temperature. The electrical parameters such as ideality factor (2.3, barrier height (0.72 eV and series resistance (33 W were evaluated from I(V data, the threshold voltage (-2.42 V, the 2D gas density (1.35 ´ 1013 cm-2 and barrier height (0.94 eV were evaluated from C(V data.

  12. Improving the turnaround maintenance of the Escravos gas plant / Ishekwene, I.V.

    OpenAIRE

    Ishekwene, Isaac Victor

    2011-01-01

    According to Oliver (2002) the success of turnaround maintenances is measured in terms of the cost of completion, time, safety performance and the performance of the plant afterwards. The Escravos gas plant (EGP) is a gas processing plant that converts associated gas from Chevron owned crude oil wells to liquefied petroleum gas, natural gas and gas condensate (Chevron intranet. Website assessed on September 14, 2007). According to the EGP plant operations coordinator (See inter...

  13. Fabrication of n-ZnO/ p-Si (100) and n-ZnO:Al/ p-Si (100) Heterostructures and Study of Current-Voltage, Capacitance-Voltage and Room-Temperature Photoluminescence

    Science.gov (United States)

    Shah, M. A. H.; Khan, M. K. R.; Tanveer Karim, A. M. M.; Rahman, M. M.; Kamruzzaman, M.

    2018-01-01

    Heterojunction diodes of n-ZnO/ p-Si (100) and n-ZnO:Al/ p-Si (100) were fabricated by spray pyrolysis technique. X-ray diffraction (XRD), energy dispersive x-ray spectroscopy (EDX), and field emission scanning electron microscopy (FESEM) were used to characterize the as-prepared samples. The XRD pattern indicates the hexagonal wurzite structure of zinc oxide (ZnO) and Al-doped ZnO (AZO) thin films grown on Si (100) substrate. The compositional analysis by EDX indicates the presence of Al in the AZO structure. The FESEM image indicates the smooth and compact surface of the heterostructures. The current-voltage characteristics of the heterojunction confirm the rectifying diode behavior at different temperatures and illumination intensities. For low forward bias voltage, the ideality factors were determined to be 1.24 and 1.38 for un-doped and Al-doped heterostructures at room temperature (RT), respectively, which indicates the good diode characteristics. The capacitance-voltage response of the heterojunctions was studied for different oscillation frequencies. From the 1/ C 2- V plot, the junction built-in potentials were found 0.30 V and 0.40 V for un-doped and Al-doped junctions at RT, respectively. The differences in built-in potential for different heterojunctions indicate the different interface state densities of the junctions. From the RT photoluminescence (PL) spectrum of the n-ZnO/ p-Si (100) heterostructure, an intense main peak at near band edge (NBE) 378 nm (3.28 eV) and weak deep-level emissions (DLE) centered at 436 nm (2.84 eV) and 412 nm (3.00 eV) were observed. The NBE emission is attributed to the radiative recombination of the free and bound excitons and the DLE results from the radiative recombination through deep level defects.

  14. Performance predictions for solar-chemical converters based on photoelectrochemical I-V curves

    Energy Technology Data Exchange (ETDEWEB)

    Luttmer, J.D.; Trachtenberg, I.

    1985-06-01

    Texas Instruments' solar energy system contains a solar-chemical converter (SCC) which converts solar energy into chemical energy via the electrolysis of hydrobromic acid (HBr) into hydrogen (H/sub 2/) and bromine (Br/sub 2/). Previous predictions of SCC performance have employed electrical dry-probe data and a computer simulation model to predict the H/sub 2/ generation rates. The method of prediction described here makes use of the photoelectrochemical Icurves to determine the ''wet'' probe parameters of V /SUB oc/ J /SUB sc/ FF, and efficiency for anodes and cathodes. The advantages of this technique over the dry-probe/computer simulation method are discussed. A comparison of predicted and measured H/sub 2/ generation rates is presented. Solar to chemical efficiencies of 8.6% have been both predicted and measured for the electrolysis of 48% HBr to hydrogen and bromine by a full anode/cathode array. Individual cathode solar to hydrogen efficiencies of 9.5% have been obtained.

  15. Artemisia annua dried leaf tablets treated malaria resistant to ACT and i.v. artesunate: Case reports.

    Science.gov (United States)

    Daddy, Nsengiyumva Bati; Kalisya, Luc Malemo; Bagire, Pascal Gisenya; Watt, Robert L; Towler, Melissa J; Weathers, Pamela J

    2017-08-15

    Dried leaf Artemisia annua (DLA) has shown efficacy against Plasmodium sp. in rodent studies and in small clinical trials. Rodent malaria also showed resiliency against the evolution of artemisinin drug resistance. This is a case report of a last resort treatment of patients with severe malaria who were responding neither to artemisinin combination therapy (ACT) nor i.v. artesunate. Of many patients treated with ACTs and i.v. artesunate during the 6 mon study period, 18 did not respond and were subsequently treated with DLA Artemisia annua. Patients were given a dose of 0.5g DLA per os, twice daily for 5d. Total adult delivered dose of artemisinin was 55mg. Dose was reduced for body weight under 30kg. Clinical symptoms, e.g. fever, coma etc., and parasite levels in thick blood smears were tracked. Patients were declared cured and released from hospital when parasites were microscopically undetectable and clinical symptoms fully subsided. All patients were previously treated with Coartem® provided through Santé Rurale (SANRU) and following the regimen prescribed by WHO. Of 18 ACT-resistant severe malaria cases compassionately treated with DLA, all fully recovered. Of the 18, this report details two pediatric cases. Successful treatment of all 18 ACT-resistant cases suggests that DLA should be rapidly incorporated into the antimalarial regimen for Africa and possibly wherever else ACT resistance has emerged. Copyright © 2017. Published by Elsevier GmbH.

  16. [Influence of valproic acid (depakine I.V.) on human placenta metabolism--experimental model].

    Science.gov (United States)

    Semczuk-Sikora, Anna; Rogowska, Wanda; Semczuk, Marian

    2003-08-01

    The pregnancy in women with epilepsy is associated with an increased incidence of congenital malformations in offspring. Currently, anti-epileptic drugs (AEDs) are concerned to be a major etiologic factor of abnormal fetal development but the pathomechanism of teratogenicity of AEDs is complex and not well understood. The purpose of this study was to evaluate an influence of one of the AED-valproic acid (VPA) on placental metabolism (glucose consumption and lactate production). Term human placental cotyledons were perfused in vitro using a recycling perfusion of maternal and fetal circulations. A total 18 placentas were perfused either with 75 micrograms/ml of VPA (therapeutic dose) or with 225 micrograms/ml of VPA (toxic dose). Eight placentas were perfused with a medium without VPA and served as controls. During 2.5 h of experiment, both maternal and fetal glucose consumption and lactate production were measured every 30 minutes. The introduction of different concentrations of VPA into the perfusion system did not effect placental glucose consumption and lactate production rates in both maternal and fetal compartments. The teratogenic effect of valproic acid is not associated with metabolic disturbances of glucose or lactate in the placental tissue.

  17. Improving antimicrobial prescribing: implementation of an antimicrobial i.v.-to-oral switch policy.

    Science.gov (United States)

    McCallum, A D; Sutherland, R K; Mackintosh, C L

    2013-01-01

    Antimicrobial stewardship programmes reduce the risk of hospital associated infections (HAI) and antimicrobial resistance, and include early intravenous-to-oral switch (IVOS) as a key stewardship measure. We audited the number of patients on intravenous antimicrobials suitable for oral switch, assessed whether prescribing guidelines were followed and reviewed prescribing documentation in three clinical areas in the Western General Hospital, Edinburgh, in late 2012. Following this, the first cycle results and local guidelines were presented at a local level and at the hospital grand rounds, posters with recommendations were distributed, joint infection consult and antimicrobial rounds commenced and an alert antimicrobial policy was introduced before re-auditing in early 2013. We demonstrate suboptimal prescribing of intravenous antimicrobials, with 43.9% (43/98) of patients eligible for IVOS at the time of auditing. Only 56.1% (55/98) followed empiric prescribing recommendations. Documentation of antimicrobial prescribing was poor with stop dates recorded in 14.3%, indication on prescription charts in 18.4% and in the notes in 90.8%. The commonest reason for deferring IVOS was deteriorating clinical condition or severe sepsis. Further work to encourage prudent antimicrobial prescribing and earlier consideration of IVOS is required.

  18. Standard Test Methods for Measurement of Electrical Performance and Spectral Response of Nonconcentrator Multijunction Photovoltaic Cells and Modules

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 These test methods provide special techniques needed to determine the electrical performance and spectral response of two-terminal, multijunction photovoltaic (PV) devices, both cell and modules. 1.2 These test methods are modifications and extensions of the procedures for single-junction devices defined by Test Methods E948, E1021, and E1036. 1.3 These test methods do not include temperature and irradiance corrections for spectral response and current-voltage (I-V) measurements. Procedures for such corrections are available in Test Methods E948, E1021, and E1036. 1.4 These test methods may be applied to cells and modules intended for concentrator applications. 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and ...

  19. TRAZADOR DE CURVAS I-V DE CÓDIGO ABIERTO PARA MONITOREO DE RENDIMIENTO DE PANELES FOTOVOLTAICOS EN BOLIVIA

    Directory of Open Access Journals (Sweden)

    Tatiana Vargas

    2014-07-01

    Full Text Available Se presenta el desarrollo de un trazador de curva I-V de código abierto para el monitoreo de potencia producida por un panel solar en Bolivia, y los resultados obtenidos por éste. El dispositivo está elaborado con componentes de bajo costo y es posible adaptar su diseño para monitorear paneles de diferentes potencias. El dispositivo toma muestras de corriente y voltaje para un elemento fotovoltaico utilizando una carga variable para obtener los diferentes puntos que conforman una curva corriente-voltaje. El dispositivo también tiene un régimen de control, el cual desconecta y reconecta el panel de su carga en intervalos de tiempo fijos para la toma de datos, permitiendo el monitoreo del panel aun cuando está siendo  utilizado en un sistema de energía solar.

  20. Hepatic 123I-insulin binding kinetics in non-insulin-dependent (Type 2) diabetic patients after i.v. bolus administration

    International Nuclear Information System (INIS)

    Oolbekkink, M.; Veen, E.A. van der; Heine, R.J.; Hollander, W. den; Nauta, J.J.P.

    1989-01-01

    Insulin binding kinetics in the liver were studied in non insulin dependent (Type 2) diabetic patients, by i.v. bolus administration of 123 I-insulin. Eight Type 2 diabetic patients were compared with six male volunteers. Uptake of 123 I-insulin by liver and kidneys was measured by dynamic scintigraphy with a gamma camera during 30 min. Images of liver and kidneys appeared within 2-3 min after administration of 123 I-insulin at a dose of 1 mCi (37 MBq). Peak radioactivity for the liver was found 7.5±0.2 and 6.9±0.3 min after injection for the healthy and the diabetic subjects, respectively (N.S.). The percentage 123 I-insulin hepatic uptake was not significantly different for the diabetic and the healthy subjects. Although a large variation exists for maximal uptake of radioactivity within both groups, the data suggest that binding differences in the liver in Type 2 diabetic patients, as compared to healthy subjects, may not account for hepatic insulin resistance. (orig.)

  1. Intelligent fault diagnosis of photovoltaic arrays based on optimized kernel extreme learning machine and I-V characteristics

    International Nuclear Information System (INIS)

    Chen, Zhicong; Wu, Lijun; Cheng, Shuying; Lin, Peijie; Wu, Yue; Lin, Wencheng

    2017-01-01

    Highlights: •An improved Simulink based modeling method is proposed for PV modules and arrays. •Key points of I-V curves and PV model parameters are used as the feature variables. •Kernel extreme learning machine (KELM) is explored for PV arrays fault diagnosis. •The parameters of KELM algorithm are optimized by the Nelder-Mead simplex method. •The optimized KELM fault diagnosis model achieves high accuracy and reliability. -- Abstract: Fault diagnosis of photovoltaic (PV) arrays is important for improving the reliability, efficiency and safety of PV power stations, because the PV arrays usually operate in harsh outdoor environment and tend to suffer various faults. Due to the nonlinear output characteristics and varying operating environment of PV arrays, many machine learning based fault diagnosis methods have been proposed. However, there still exist some issues: fault diagnosis performance is still limited due to insufficient monitored information; fault diagnosis models are not efficient to be trained and updated; labeled fault data samples are hard to obtain by field experiments. To address these issues, this paper makes contribution in the following three aspects: (1) based on the key points and model parameters extracted from monitored I-V characteristic curves and environment condition, an effective and efficient feature vector of seven dimensions is proposed as the input of the fault diagnosis model; (2) the emerging kernel based extreme learning machine (KELM), which features extremely fast learning speed and good generalization performance, is utilized to automatically establish the fault diagnosis model. Moreover, the Nelder-Mead Simplex (NMS) optimization method is employed to optimize the KELM parameters which affect the classification performance; (3) an improved accurate Simulink based PV modeling approach is proposed for a laboratory PV array to facilitate the fault simulation and data sample acquisition. Intensive fault experiments are

  2. Association between continuous peripheral i.v. infusion of 3% sodium chloride injection and phlebitis in adults.

    Science.gov (United States)

    Meng, Lina; Nguyen, Cherwyn M; Patel, Samit; Mlynash, Michael; Caulfield, Anna Finley

    2018-03-01

    One institution's experience with use of peripheral i.v. (PIV) catheters for prolonged infusions of 3% sodium chloride injection at rates up to 100 mL/hr is described. A prospective, observational, 13-month quality assurance project was conducted at an academic medical center to evaluate frequencies of patient and catheter phlebitis among adult inpatients who received both an infusion of 3% sodium chloride injection for a period of ≥4 hours through a dedicated PIV catheter and infusions of routine-care solutions (RCSs) through separate PIV catheters during the same hospital stay. Sixty patients received PIV infusions through a total of 291 catheters during the study period. The majority of patients (78%) received infusions of 3% sodium chloride injection for intracranial hypertension, with 30% receiving such infusions in the intensive care unit. Phlebitis occurred in 28 patients (47%) during infusions of 3% sodium chloride and 26 patients (43%) during RCS infusions ( p = 0.19). Catheter phlebitis occurred in 73 catheters (25%), with no significant difference in the frequencies of catheter phlebitis with infusion of 3% sodium chloride versus RCSs (30% [32 of 106 catheters]) versus 22% [41 of 185 catheters]), p = 0.16). Patient and catheter phlebitis rates were not significantly different with infusions of 3% sodium chloride injection versus RCSs, suggesting that an osmolarity cutoff value of 900 mOsm/L for peripheral infusions of hypertonic saline solutions may not be warranted. Copyright © 2018 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  3. Inappropriate suppression of glucagon during OGTT but not during isoglycaemic i.v. glucose infusion contributes to the reduced incretin effect in type 2 diabetes mellitus

    DEFF Research Database (Denmark)

    Knop, F K; Vilsbøll, T; Madsbad, S

    2007-01-01

    AIMS/HYPOTHESIS: We investigated glucagon responses during OGTT and isoglycaemic i.v. glucose infusion, respectively, to further elucidate the mechanisms behind the glucose intolerance in patients with type 2 diabetes. MATERIALS AND METHODS: Ten patients (eight men) with type 2 diabetes (age: 64...... during the 2 days was obtained in both groups. In the control subjects no difference in glucagon suppression during the first 45 min of OGTT and isoglycaemic i.v. glucose infusion (-36 +/- 12 vs -64 +/- 23 mmol/l x 45 min; p = NS) was observed, whereas in the group of patients with type 2 diabetes...... significant glucagon suppression only occurred following isoglycaemic i.v. glucose infusion (-63 +/- 21 vs 10 +/- 16 mmol/l x 45 min; p = 0.002). The incretin effect was significantly reduced in patients with type 2 diabetes compared with control subjects, but no significant differences in the secretion...

  4. Measurement of communication

    International Nuclear Information System (INIS)

    1998-08-01

    This book is one of series of information communication, which deals with measurement of communication. It is divided into six chapters. The contents are foundation of measurement with classification and principle, Basic measurement on current, voltage, electric resistance, power and impedance, measurement of communication line with way by L3 tester, BW tester and pulse tester, measurement of optical fiber cable of equipment and method, Test and measurement of information communication equipment about test of modulator and use, measurement of cable broadcasting equipment on transmission level and main transmission equipment.

  5. The influence of internal current loop on transient response performance of I-V droop controlled paralleled DC-DC converters

    DEFF Research Database (Denmark)

    Wang, Haojie; Han, Minxiao; Guerrero, Josep M.

    2017-01-01

    The external droop control loop of I-V droop control is designed as a voltage loop with embedded virtual impedance, so the internal current loop plays a major role in the system bandwidth. Thus, in this paper, the influence of internal current loop on transient response performance of I-V droop...... controlled paralleled dc-dc converters is analyzed, which is guided and significant for its industry application. The model which is used for dynamic analysis is built, and the root locus method is used based on the model to analyze the dynamic response of the system by shifting different control parameters...

  6. Autoshaping i.v. cocaine self-administration in rats: effects of nondrug alternative reinforcers on acquisition.

    Science.gov (United States)

    Carroll, M E; Lac, S T

    1993-01-01

    The purpose of this experiment was to examine the effects of a nondrug alternative reinforcer and feeding conditions on the acquisition of cocaine self-administration. Rats were autoshaped to press a lever that resulted in a 0.2 mg/kg i.v. cocaine infusion. Responses on the lever were monitored during six consecutive autoshaping sessions that occurred each day. A retractable lever was inserted into the operant chamber on a random time 60 s schedule 10 times per session for six sessions that began each hour. Each day the six autoshaping sessions were followed by a 6-h cocaine self-administration session. During self-administration the lever remained extended, and each response on the lever resulted in a cocaine infusion (0.2 mg/kg). The criterion for acquisition of cocaine-reinforced behavior was met when there were 5 consecutive days during which the mean number of infusions during the 6-h self-administration session was at least 100. This procedure was repeated daily until the criterion was met or 30 days elapsed. The rats were also trained to respond on lick-operated automatic drinking devices that delivered 0.05 ml water or a glucose and saccharin solution (G + S) contingent upon each lick response. Five groups of 12-14 rats were compared. The first four groups constituted a 2 x 2 factorial design whereby either G + S or water was available in the home cage for 3 weeks before autoshaping began and G + S or water was available in the operant chamber during autoshaping. These groups were limited to 20 g food per day and all had free access to water.(ABSTRACT TRUNCATED AT 250 WORDS)

  7. Effect of current compliance and voltage sweep rate on the resistive switching of HfO2/ITO/Invar structure as measured by conductive atomic force microscopy

    International Nuclear Information System (INIS)

    Wu, You-Lin; Liao, Chun-Wei; Ling, Jing-Jenn

    2014-01-01

    The electrical characterization of HfO 2 /ITO/Invar resistive switching memory structure was studied using conductive atomic force microscopy (AFM) with a semiconductor parameter analyzer, Agilent 4156C. The metal alloy Invar was used as the metal substrate to ensure good ohmic contact with the substrate holder of the AFM. A conductive Pt/Ir AFM tip was placed in direct contact with the HfO 2 surface, such that it acted as the top electrode. Nanoscale current-voltage (I-V) characteristics of the HfO 2 /ITO/Invar structure were measured by applying a ramp voltage through the conductive AFM tip at various current compliances and ramp voltage sweep rates. It was found that the resistance of the low resistance state (RLRS) decreased with increasing current compliance value, but resistance of high resistance state (RHRS) barely changed. However, both the RHRS and RLRS decreased as the voltage sweep rate increased. The reasons for this dependency on current compliance and voltage sweep rate are discussed.

  8. Formulation and characterization of biocompatible and stable I.V. itraconazole nanosuspensions stabilized by a new stabilizer polyethylene glycol-poly(β-Benzyl-l-aspartate) (PEG-PBLA).

    Science.gov (United States)

    Zong, Lanlan; Li, Xiaohua; Wang, Haiyan; Cao, Yanping; Yin, Li; Li, Mengmeng; Wei, Zhihao; Chen, Dongxiao; Pu, Xiaohui; Han, Jihong

    2017-10-05

    Amphiphilic block copolymers, PEG-PBLA with different molecular weights, were synthesized and used as new stabilizers for Itraconazole nannosuspensions (ITZ-PBLA-Nanos). ITZ-PBLA-Nanos were prepared by the microprecipitation-high pressure homogenization method, and the particle size and zeta potential were measured using a ZetaSizer Nano-ZS90. Morphology and crystallinity were studied using TEM, DSC and powder X-ray. The effect of the PEG-to-PBLA ratio, and the drug-to-stabilizer ratio were investigated to obtain the optimal formulation. It was found that the optimal length of hydrophobic block was 25 BLA-NCA molecules and the optimal ratio of drug/stabilizer was 1:1, where the resulted average particle size of ITZ-PBLA-Nanos was 262.1±7.13nm with a PDI value of 0.163±0.011. The images of TEM suggest that ITZ-PBLA-Nanos were rectangular in shape. ITZ existed as crystals in the nanoparticles as suggested by the DSC and XRD results. Compared with the crude drug suspensions, the dissolution rate of ITZ nanocrystals, was significantly increased and was similar to Sporanox ® injection. The ITZ-PBLA-Nanos also demonstrated better dilution stability and storage stability compared with ITZ-F68-Nanos. The particle size of ITZ-PBLA-Nanos did not change significantly after incubated in rat plasma for 24h which is a good attribute for I.V. administration. Acute toxicity tests showed that ITZ-PBLA-Nanos has the highest LD 50 compared with ITZ-F68-Nanos and Sporanox ® injection. ITZ-PBLA-Nanos also showed stronger inhibiting effect on the growth of Candida albicans compared with Sporanox ® injection. Therefore, PEG-PBLA has a promising potential as a biocompatible stabilizer for ITZ nanosuspensions and potentially for other nanosuspensions as well. Copyright © 2017. Published by Elsevier B.V.

  9. Development of microsecond generators with plasma current interrupting switch in I.V. Kurchatov Institute of Atomic Energy. Frequency operation of generators

    International Nuclear Information System (INIS)

    Babykin, V.M.; Chikin, R.V.; Dolgachev, G.I.; Golovanov, Yu.P.; Kovalev, Yu.I.; Ushakov, A.G.; Zakatov, L.P.

    1993-01-01

    This paper is a follow up to previously published work on microsecond plasma current interrupting switches (PCIS), which has been conducted in the I.V. Kurchatov Inst. Here the authors present some information on the practical implementation of such devices, and provide an overview of new research facilities

  10. Elucidating PID Degradation Mechanisms and In Situ Dark I-V Monitoring for Modeling Degradation Rate in CdTe Thin-Film Modules

    DEFF Research Database (Denmark)

    Hacke, Peter; Spataru, Sergiu; Johnston, Steve

    2016-01-01

    A progression of potential-induced degradation (PID) mechanisms are observed in CdTe modules, including shunting/junction degradation and two different manifestations of series resistance depending on the stress level and water ingress. The dark I-V method for in-situ characterization of Pmax bas...

  11. Natures and incidences of each normal variations on I.V.P. series of 1000 Korean females

    International Nuclear Information System (INIS)

    Shin, Ok Ja; Chin, Soo Yil

    1980-01-01

    Each organ of body has many normal variation and/or abnormal developments from fetus to adult, especially urogenital system is very complex and markedly abnormal. The authors attempt to analyze the natures, incidences and differences of each normal variations based on I.V.P. series of 1000 Korean females and the review of literatures were carried out. The results are as follows: 1. The normal variations of urinary tracts are about 30 kinds as follows; Aphasia 0/1000 (0%), Hypoplasia 4/1000 (0.4%), Atrophic kidney 0/1000 (0%), Hyperplasia 0/1000 (0%), Hypertrophied kidney 0/1000 (0%), Supernumerary kidney 0/1000 (0%), Pelvic kidney 0/1000 (0%), Wandering kidney 7/1000 (7%), Horseshoe kidney 2/1000 (2%), Nephroptosis 6/1000 (0.6%), Malroated kidney 0/1000 (0%), Crossed ecotopic kidney 0/1000 (0%), Ureteral kingking 440/1000 (44.0%), Short ureter 3/1000 (0.3%), Long ureter 49/1000 (4.9%), Retrocaval ureter 0/1000 (0%), Retroiliac ureter 0/1000 (0%), Mega-ureter 0/1000 (0%), Aberrant vessel in ureter 79/1000 (7.9%), Congenital ureteral valves 0/1000 (0%), Anomalous ureteral orifices 0/1000 (0%), Double ureter 22/1000 (2.2%), Ureteral diverticulum 0/1000 (0%), Extrarenal pelvis 170/1000 (17.0%), Intrarenal pelvis 830/1000 (83.0%), Supernumerary pelvis 55/1000 (55%), Renal backflow 2/1000 0.2%), Multiple calyces 0/1000 (0.1%), Calyceal diverticulum 2/1000 (0.2%), Unilateral fused kidney 0/1000 (0%), Polar enlarged kidney 0/1000 (0%). 2. The order of incidence of common variations in Korean females are as follows: 1. Intrarenal pelvis 2. Ureteral kingking 3. Extrarenal pelvis 4. Aberrant vessel in ureter 5. Double pelvis 6. Long ureter 7. Double ureter 8. Wandering Kidney 9. Nephrotosis 10. Hypoplasia 11. Short ureter 12. Horseshoe kidney 13. Renal backflow 14. Calyceal diverticulum 15. Supernumerary calyces. 3. The most common variations in Korean females are intrarenal pelvis, extrarenal pelvis, aberrant vessel in ureters and most of them are acquired origin. Contrary

  12. Manifestation of π-contacts in magnetic field dependence of I-V characteristics for proximity-type 2D Josephson junction array

    International Nuclear Information System (INIS)

    Rivera, V.A.G.; Sergeenkov, S.; Marega, E.; Araujo-Moreira, F.M.

    2009-01-01

    Results on the temperature and magnetic field dependence of current-voltage characteristics (CVC) are presented for SNS-type 2D ordered array of Nb-Cu 0.95 Al 0.05 -Nb junctions. The critical current I C (T,H) and the power exponent a(T,H)=1+Φ 0 I C (T,H)/2k B T of the nonlinear CVC law V=R[I-I C (T,H)] a(T,H) are found to have a maximum at non-zero value of applied magnetic field H p =225 Oe, which is attributed to manifestation of π-type Josephson contacts in our sample.

  13. Cocaine action on peripheral, non-monoamine neural substrates as a trigger of electroencephalographic desynchronization and electromyographic activation following i.v. administration in freely moving rats.

    Science.gov (United States)

    Smirnov, M S; Kiyatkin, E A

    2010-01-20

    Many important physiological, behavioral and subjective effects of i.v. cocaine (COC) are exceptionally rapid and transient, suggesting a possible involvement of peripheral neural substrates in their triggering. In the present study, we used high-speed electroencephalographic (EEG) and electromyographic (EMG) recordings (4-s resolution) in freely moving rats to characterize the central electrophysiological effects of i.v. COC at low doses within a self-administration range (0.25-1.0 mg/kg). We found that COC induces rapid, strong, and prolonged desynchronization of cortical EEG (decrease in alpha and increase in beta and gamma activity) and activation of the neck EMG that begin within 2-6 s following the start of a 10-s injection; immediate components of both effects were dose-independent. The rapid effects of COC were mimicked by i.v. COC methiodide (COC-MET), a derivative that cannot cross the blood-brain barrier. At equimolar doses (0.33-1.33 mg/kg), COC-MET had equally fast and strong effects on EEG and EMG total powers, decreasing alpha and increasing beta and gamma activities. Rapid EEG desynchronization and EMG activation was also induced by i.v. procaine, a structurally similar, short-acting local anesthetic with virtually no effects on monoamine uptake; at equipotential doses (1.25-5.0 mg/kg), these effects were weaker and shorter in duration than those of COC. Surprisingly, i.v. saline injection delivered during slow-wave sleep (but not during quiet wakefulness) also induced a transient EEG desynchronization but without changes in EMG and motor activity; these effects were significantly weaker and much shorter than those induced by all tested drugs. These data suggest that in awake animals, i.v. COC induces rapid cortical activation and a subsequent motor response via its action on peripheral non-monoamine neural elements, involving neural transmission via visceral sensory pathways. By providing a rapid neural signal and triggering neural activation, such

  14. Adriamycin continuous i.v. infusion for the treatment of childhood hepatic malignancies, toxicity and efficacy: a pilot study childrens cancer study group

    International Nuclear Information System (INIS)

    Ortega, J.A.; Feusner, J.; Reaman, G.; Woods, W.

    1986-01-01

    In an effort to increase the number of patients with hepatoblastoma and hepatocellular carcinoma receiving the benefits of complete surgical excision, a pilot study was undertaken at a few Childrens Cancer Study Group institutions. For this purpose, repeated courses of adriamycin administered as a continuous I.V. infusion either singly or in combination with c-platinum and radiation therapy treatment was selected. The patient population consisted of a total of eleven children with primary hepatic malignancies: six children had hepatoblastoma; all six were under two years of age at diagnosis. Five patients with hepatocellular carcinoma were entered to the study. Of the eleven patients, four had previously received adriamycin as an I.V. bolus. A table summarizes the patient's characteristics, the adriamycin dose they received and their responses to therapy

  15. Simulation, measurement, and emulation of photovoltaic modules using high frequency and high power density power electronic circuits

    Science.gov (United States)

    Erkaya, Yunus

    The number of solar photovoltaic (PV) installations is growing exponentially, and to improve the energy yield and the efficiency of PV systems, it is necessary to have correct methods for simulation, measurement, and emulation. PV systems can be simulated using PV models for different configurations and technologies of PV modules. Additionally, different environmental conditions of solar irradiance, temperature, and partial shading can be incorporated in the model to accurately simulate PV systems for any given condition. The electrical measurement of PV systems both prior to and after making electrical connections is important for attaining high efficiency and reliability. Measuring PV modules using a current-voltage (I-V) curve tracer allows the installer to know whether the PV modules are 100% operational. The installed modules can be properly matched to maximize performance. Once installed, the whole system needs to be characterized similarly to detect mismatches, partial shading, or installation damage before energizing the system. This will prevent any reliability issues from the onset and ensure the system efficiency will remain high. A capacitive load is implemented in making I-V curve measurements with the goal of minimizing the curve tracer volume and cost. Additionally, the increase of measurement resolution and accuracy is possible via the use of accurate voltage and current measurement methods and accurate PV models to translate the curves to standard testing conditions. A move from mechanical relays to solid-state MOSFETs improved system reliability while significantly reducing device volume and costs. Finally, emulating PV modules is necessary for testing electrical components of a PV system. PV emulation simplifies and standardizes the tests allowing for different irradiance, temperature and partial shading levels to be easily tested. Proper emulation of PV modules requires an accurate and mathematically simple PV model that incorporates all known

  16. Bio-social factors and perceptions of life with quality: a challenge to the adherence of h i v patients to the antirretroviral treatment

    Directory of Open Access Journals (Sweden)

    John Harold Estrada M

    2008-06-01

    Full Text Available In spite that antirretroviral therapy has contributed to improve life quality among people living with h i v, adherence to the treatment still persists as a major obstacle for therapeutic success. In order to assess the biosocial factors that contributes to adherence to this therapy by people with h i v. In order to evaluate the bio-social aspects that facilitate or obstruct the adherence to the treatment, a qualitative study combining ethnographic research, a hermeneutic approach to narratives, and a situational analysis of life experiences of people living with h i v in Colombia. Two theoretical categories were applied throughout the study: Victoria Camps’ life with quality and Saussure’s auto- and hetero-perception. All of the ten people who took part in the study were male patients who were attending an integral oral health program. The main factors that obstruct the adherence to the therapy were the following: 1 the discourse of the medical team loaded with biomedical jargon; 2 the dosages and side effects of the medications used in Colombia; 3 negative attitudes linked to a poor selfimage, a low social capital, and a low self-esteem; 4 low expectations in regards to a life with quality accompanied by the therapy. Among the factors that promote adherence the following were identified: 1 intra- and inter-personal negotiation processes based on the h i v serum status and the treatment; 2 knowledge about those negotiations by family members, friends, coworkers, and sentimental partners; 3 a positive perception of improvement in life quality while in treatment; 4 expectations of a life with quality depending on the adherence. Nevertheless, it was also found that those factors that contribute or impede adherence change rapidly and produce swinging in the person’s mood. This mood is here understood as a complex feeling concerning life with quality in constant change, both merging individual and social aspects implied in the experience of

  17. Vortex depinning as a nonequilibrium phase transition phenomenon: Scaling of current-voltage curves near the low and the high critical-current states in 2 H -Nb S2 single crystals

    Science.gov (United States)

    Bag, Biplab; Sivananda, Dibya J.; Mandal, Pabitra; Banerjee, S. S.; Sood, A. K.; Grover, A. K.

    2018-04-01

    The vortex depinning phenomenon in single crystals of 2 H -Nb S2 superconductors is used as a prototype for investigating properties of the nonequilibrium (NEQ) depinning phase transition. The 2 H -Nb S2 is a unique system as it exhibits two distinct depinning thresholds, viz., a lower critical current Icl and a higher one Ich. While Icl is related to depinning of a conventional, static (pinned) vortex state, the state with Ich is achieved via a negative differential resistance (NDR) transition where the velocity abruptly drops. Using a generalized finite-temperature scaling ansatz, we study the scaling of current (I)-voltage (V) curves measured across Icl and Ich. Our analysis shows that for I >Icl , the moving vortex state exhibits Arrhenius-like thermally activated flow behavior. This feature persists up to a current value where an inflexion in the IV curves is encountered. While past measurements have often reported similar inflexion, our analysis shows that the inflexion is a signature of a NEQ phase transformation from a thermally activated moving vortex phase to a free flowing phase. Beyond this inflection in IV, a large vortex velocity flow regime is encountered in the 2 H -Nb S2 system, wherein the Bardeen-Stephen flux flow limit is crossed. In this regime the NDR transition is encountered, leading to the high Ich state. The IV curves above Ich we show do not obey the generalized finite-temperature scaling ansatz (as obeyed near Icl). Instead, they scale according to the Fisher's scaling form [Fisher, Phys. Rev. B 31, 1396 (1985), 10.1103/PhysRevB.31.1396] where we show thermal fluctuations do not affect the vortex flow, unlike that found for depinning near Icl.

  18. I-V and C-V Characterization of a High-Responsivity Graphene/Silicon Photodiode with Embedded MOS Capacitor.

    Science.gov (United States)

    Luongo, Giuseppe; Giubileo, Filippo; Genovese, Luca; Iemmo, Laura; Martucciello, Nadia; Di Bartolomeo, Antonio

    2017-06-27

    We study the effect of temperature and light on the I-V and C-V characteristics of a graphene/silicon Schottky diode. The device exhibits a reverse-bias photocurrent exceeding the forward current and achieves a photoresponsivity as high as 2.5 A / W . We show that the enhanced photocurrent is due to photo-generated carriers injected in the graphene/Si junction from the parasitic graphene/SiO₂/Si capacitor connected in parallel to the diode. The same mechanism can occur with thermally generated carriers, which contribute to the high leakage current often observed in graphene/Si junctions.

  19. Full splitting of the first zero-field steps in the I-V curve of Josephson junctions of intermediate length

    International Nuclear Information System (INIS)

    Hansen, J.B.; Divin, Y.Y.; Mygind, J.

    1986-01-01

    We report on the observation of full splitting of the first zero-field steps in the I-V curves of Josephson transmission lines of intermediate length Lroughly-equal(3--5)lambda/sub J/, where lambda/sub J/ is the Josephson penetration length. We study in detail how this splitting of the step into two branches depends on the temperature of the junction and on a weak applied magnetic field. We relate the splitting to excitations in the junctions whose behavior is described by the perturbed Sine-Gordon equation

  20. I-V and C-V Characterization of a High-Responsivity Graphene/Silicon Photodiode with Embedded MOS Capacitor

    OpenAIRE

    Luongo, Giuseppe; Giubileo, Filippo; Genovese, Luca; Iemmo, Laura; Martucciello, Nadia; Di Bartolomeo, Antonio

    2017-01-01

    We study the effect of temperature and light on the I-V and C-V characteristics of a graphene/silicon Schottky diode. The device exhibits a reverse-bias photocurrent exceeding the forward current and achieves a photoresponsivity as high as 2.5 ? A / W . We show that the enhanced photocurrent is due to photo-generated carriers injected in the graphene/Si junction from the parasitic graphene/SiO2/Si capacitor connected in parallel to the diode. The same mechanism can occur with thermally genera...

  1. Development of a switched integrator amplifier for high-accuracy optical measurements

    International Nuclear Information System (INIS)

    Mountford, John; Porrovecchio, Geiland; Smid, Marek; Smid, Radislav

    2008-01-01

    In the field of low flux optical measurements, the development and use of large area silicon detectors is becoming more frequent. The current/voltage conversion of their photocurrent presents a set of problems for traditional transimpedance amplifiers. The switched integration principle overcomes these limitations. We describe the development of a fully characterized current-voltage amplifier using the switched integrator technique. Two distinct systems have been developed in parallel at the United Kingdom's National Physical Laboratory (NPL) and Czech Metrology Institute (CMI) laboratories. We present the circuit theory and best practice in the design and construction of switched integrators. In conclusion the results achieved and future developments are discussed

  2. Development of a switched integrator amplifier for high-accuracy optical measurements.

    Science.gov (United States)

    Mountford, John; Porrovecchio, Geiland; Smid, Marek; Smid, Radislav

    2008-11-01

    In the field of low flux optical measurements, the development and use of large area silicon detectors is becoming more frequent. The current/voltage conversion of their photocurrent presents a set of problems for traditional transimpedance amplifiers. The switched integration principle overcomes these limitations. We describe the development of a fully characterized current-voltage amplifier using the switched integrator technique. Two distinct systems have been developed in parallel at the United Kingdom's National Physical Laboratory (NPL) and Czech Metrology Institute (CMI) laboratories. We present the circuit theory and best practice in the design and construction of switched integrators. In conclusion the results achieved and future developments are discussed.

  3. Magneto-electronic properties and spin-resolved I-V curves of a Co/GeSe heterojunction diode: an ab initio study

    Science.gov (United States)

    Makinistian, Leonardo; Albanesi, Eduardo A.

    2013-06-01

    We present ab initio calculations of magnetoelectronic and transport properties of the interface of hcp Cobalt (001) and the intrinsic narrow-gap semiconductor germanium selenide (GeSe). Using a norm-conserving pseudopotentials scheme within DFT, we first model the interface with a supercell approach and focus on the spin-resolved densities of states and the magnetic moment (spin and orbital components) at the different atomic layers that form the device. We also report a series of cuts (perpendicular to the plane of the heterojunction) of the electronic and spin densities showing a slight magnetization of the first layers of the semiconductor. Finally, we model the device with a different scheme: using semiinfinite electrodes connected to the heterojunction. These latter calculations are based upon a nonequilibrium Green's function approach that allows us to explore the spin-resolved electronic transport under a bias voltage (spin-resolved I-V curves), revealing features of potential applicability in spintronics.

  4. ARTIFICIAL INTELLIGENT SYSTEM FOR MEASUREMENT OF HARMONIC POWERS

    Directory of Open Access Journals (Sweden)

    Jovitha Jerome

    2017-11-01

    Full Text Available The importance of the electric power quality (PQ demands new methodologies and measurement tools in the power industry for the analysis and measurement of the basic electric magnitudes necessary. This paper presents a new measurement procedure based on neural networks for the estimation of harmonic amplitudes of current/voltage and respective harmonic powers. The measurement scheme is built with two neural network modules. The first module is an adaptive linear neuron (ADALINE that is the kernel part of estimation of complex harmonic coefficients of the current/voltage. The second module is feedforward neural network that obtains the harmonic active/reactive powers. In order to perform digital simulation the Feedforward and Adaline neural network tools were developed in LabVIEW. This measurement algorithm was tested for the practical cases and found to be robust, computationally fast and efficient.

  5. Simulation of I-V and C-V curves of metal/GaN/AlGaN/GaN heterostructures with trap-assisted tunnelling

    International Nuclear Information System (INIS)

    Racko, J.; Benko, P.; Grmanova, A.; Harmatha, L.; Breza, J.; Granzner, R.; Schwierz, F.

    2013-01-01

    The described trap-assisted tunnelling (TAT) model of the metal/GaN/Al_xGaN_1_-_x/GaN structure allows analyzing the effect of deep traps upon I-V and C-V characteristics. The negative charge with magnitude proportional to the molar concentration of aluminium gives rise to a barrier at the first heterojunction, which is higher than the Schottky barrier at the metal/GaN interface. On increasing the reverse bias Va the barrier at the first heterojunction is getting lower. The drop of this barrier causes an exponential increase of the reverse current. The current saturates, when the first heterojunction barrier is lower than the Schottky barrier. The effect of TAT can be observed also on varying the parameters of the band of traps. The shape of the simulated C-V curve is affected by changes in the charge on the second heterojunction. In principle it reflects the decrease of electron concentration in the quantum well on increasing the reverse bias V_a. The space charge region becomes wider and the electron concentration at the second heterojunction falls below the concentration of ionized deep trapping centres, which manifests itself as a noticeable drop in the capacitance of the metal/GaN/Al_xGaN_1_-_x/GaN structure. (authors)

  6. Stable long-term pulmonary function after fludarabine, antithymocyte globulin and i.v. BU for reduced-intensity conditioning allogeneic SCT.

    Science.gov (United States)

    Dirou, S; Malard, F; Chambellan, A; Chevallier, P; Germaud, P; Guillaume, T; Delaunay, J; Moreau, P; Delasalle, B; Lemarchand, P; Mohty, M

    2014-05-01

    Lung function decline is a well-recognized complication following allogeneic SCT (allo-SCT). Reduced-intensity conditioning (RIC) and in vivo T-cell depletion by administration of antithymocyte globulin (ATG) may have a protective role in the occurrence of late pulmonary complications. This retrospective study reported the evolution of lung function parameters within the first 2 years after allo-SCT in a population receiving the same RIC regimen that included fludarabine and i.v. BU in combination with low-dose ATG. The median follow-up was 35.2 months. With a median age of 59 years at the time of transplant, at 2 years, the cumulative incidences of non-relapse mortality was as low as 9.7%. The cumulative incidence of relapse was 33%. At 2 years, the cumulative incidences of extensive chronic GVHD (cGVHD) and of pulmonary cGVHD were 23.1% and 1.9%, respectively. The cumulative incidences of airflow obstruction and restrictive pattern were 3.8% and 9.6%, respectively. Moreover, forced expiratory volume (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio remained stable from baseline up to 2 years post transplantation (P=0.26, P=0.27 and P=0.07, respectively). These results correspond favorably with the results obtained with other RIC regimens not incorporating ATG, and suggest that ATG may have a protective pulmonary role after allo-SCT.

  7. Use of continuous ambulatory infusions of concentrated subcutaneous (s.q.) hydromorphone versus intravenous (i.v.) morphine: cost implications for palliative care.

    Science.gov (United States)

    Fudin, J; Smith, H S; Toledo-Binette, C S; Kenney, E; Yu, A B; Boutin, R

    2000-01-01

    Health care practitioners are increasingly under pressure to curtail spending while trying to deliver excellent patient care. These issues are also affecting palliative care, particularly now that palliative care programs are expanding. A comparison of cost-effectiveness and feasibility of using continuous subcutaneous (s.q.) ambulatory infusion of hydromorphone versus intravenous (i.v.) ambulatory morphine is illustrated in this study. With the high doses of morphine required in chronic cancer pain, the use of subcutaneous morphine is not feasible due to the volume of solution required to be delivered. Hydromorphone can be prepared in concentrated solutions enabling it to be delivered by the subcutaneous route. Morphine stability data are available. However, hydromorphone stability has only been verified for seven days; thus, stability data were needed post-seven days. Concentrations of 10 mg/ml, 20 mg/ml, 50 mg/ml, and 100 mg/ml, in 0.9 percent normal saline or dextrose 5 percent water, were analyzed via high-performance liquid chromatography (HPLC) at seven and 28 days. Cost comparisons of supplies and associated costs with subcutaneous versus intravenous solutions were obtained. Hydromorphone was found to be stable for 28 days in both dilutants. Cost analysis of a hydromorphone 28-day supply resulted in substantial savings over the equivalent costs of morphine infusions.

  8. High diagnostic accuracy of the Sysmex XT-2000iV delta total nucleated cells on effusions for feline infectious peritonitis.

    Science.gov (United States)

    Giordano, Alessia; Stranieri, Angelica; Rossi, Gabriele; Paltrinieri, Saverio

    2015-06-01

    The ΔWBC (the ratio between DIFF and BASO counts of the Sysmex XT-2000iV), hereafter defined as ΔTNC (total nucleated cells), is high in effusions due to feline infectious peritonitis (FIP), as cells are entrapped in fibrin clots formed in the BASO reagent. Similar clots form in the Rivalta's test, a method with high diagnostic accuracy for FIP. The objective of this study was to determine the diagnostic accuracy for FIP and the optimal cutoff of ΔTNC. After a retrospective search of our database, DIFF and BASO counts, and the ΔTNC from cats with and without FIP were compared to each other. Sensitivity, specificity, and positive and negative likelihood ratios (LR+, LR-) were calculated. A ROC curve was designed to determine the cutoff for best sensitivity and specificity. Effusions from 20 FIP and 31 non-FIP cats were analyzed. The ΔTNC was higher (P  2.5 had 100% specificity. The ΔTNC has a high diagnostic accuracy for FIP-related effusions by providing an estimate of precipitable proteins, as the Rivalta's test, in addition to the cell count. As fibrin clots result in false lower BASO counts, the ΔTNC is preferable to the WBC count generated by the BASO channel alone in suspected FIP effusions. © 2015 American Society for Veterinary Clinical Pathology.

  9. Detailed clinicopathological characterization of progressive alopecia areata patients treated with i.v. corticosteroid pulse therapy toward optimization of inclusion criteria.

    Science.gov (United States)

    Sato, Misato; Amagai, Masayuki; Ohyama, Manabu

    2014-11-01

    The management of progressive alopecia areata (AA) is often challenging. Recently, i.v. corticosteroid pulse therapy has been reported to be effective for acute and severe AA, however, inclusion criteria have not been sufficiently precise, leaving a chance that its efficacy could be further improved by optimizing therapeutic indications. In our attempts to delineate the factors that correlate with favorable outcomes, we minutely evaluated the clinicopathological findings and the prognoses of single-round steroid pulse-treated progressive AA cases with full sets of image and pathology records during the course. Almost complete hair regrowth has been achieved and maintained up to 2 years in five out of seven AA patients with varying degrees of clinical severity. Interestingly, the worst clinical presentation observed during the course correlated with the size of the area where hairs with dystrophic roots were pulled rather than the extent of visible hair loss on the first visit. Dermoscopy detected disease spread but contributed little in assessing prognoses. Dense perifollicular cell infiltration was detected in all cases treated within 4 weeks of onset and those treated later but with excellent response. Importantly, the cases with poor or incomplete hair regrowth were treated 6-8 weeks of onset and showed moderate inflammatory change with high telogen conversion rate. These findings mandate global dermoscopy and hair pull test for judging the treatment indication and suggest that early administration of high-dose corticosteroid, ideally within 4 weeks of onset, enable efficient suppression of active inflammation and maximize the effectiveness of the remedy. © 2014 Japanese Dermatological Association.

  10. Stability of i.v. admixture containing metoclopramide, diphenhydramine hydrochloride, and dexamethasone sodium phosphate in 0.9% sodium chloride injection.

    Science.gov (United States)

    Kintzel, Polly E; Zhao, Ting; Wen, Bo; Sun, Duxin

    2014-12-01

    The chemical stability of a sterile admixture containing metoclopramide 1.6 mg/mL, diphenhydramine hydrochloride 2 mg/mL, and dexamethasone sodium phosphate 0.16 mg/mL in 0.9% sodium chloride injection was evaluated. Triplicate samples were prepared and stored at room temperature without light protection for a total of 48 hours. Aliquots from each sample were tested for chemical stability immediately after preparation and at 1, 4, 8, 24, and 48 hours using liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Metoclopramide, diphenhydramine hydrochloride, and dexamethasone sodium phosphate were selectively monitored using multiple-reaction monitoring. Samples were diluted differently for quantitation using three individual LC-MS/MS methods. To determine the drug concentration of the three compounds in the samples, three calibration curves were constructed by plotting the peak area or the peak area ratio versus the concentration of the calibration standards of each tested compound. Apixaban was used as an internal standard. Linearity of the calibration curve was evaluated by the correlation coefficient r(2). Constituents of the admixture of metoclopramide 1.6 mg/mL, diphenhydramine hydrochloride 2 mg/mL, and dexamethasone sodium phosphate 0.16 mg/mL in 0.9% sodium chloride injection retained more than 90% of their initial concentrations over 48 hours of storage at room temperature without protection from light. The observed variability in concentrations of these three compounds was within the limits of assay variability. An i.v. admixture containing metoclopramide 1.6 mg/mL, diphenhydramine hydrochloride 2 mg/mL, and dexamethasone sodium phosphate 0.16 mg/mL in 0.9% sodium chloride injection was chemically stable for 48 hours when stored at room temperature without light protection. Copyright © 2014 by the American Society of Health-System Pharmacists, Inc. All rights reserved.

  11. Effects of electron-irradiation on electrical properties of AgCa/Si Schottky diodes

    International Nuclear Information System (INIS)

    Harmatha, L.; Zizka, M.; Sagatova, A.; Nemec, M.; Hybler, P.

    2013-01-01

    This contribution presents the results of the current-voltage I-V and the capacitance-voltage C-V measurement on the Schottky diodes with the AgCa gate on the silicon n-type substrate. The Si substrate was irradiated by 5 MeV electrons with a different dose value before the Schottky diode preparation. (authors)

  12. Temperature-dependency analysis and correction methods of in-situ power-loss estimation for crystalline silicon modules undergoing potential-induced degradation stress testing

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Hacke, Peter; Sera, Dezso

    2015-01-01

    We propose a method of in-situ characterization of the photovoltaic module power at standard test conditions using superposition of the dark current-voltage (I-V) curve measured at elevated stress temperature during potential-induced degradation (PID) testing. PID chamber studies were performed o...

  13. Measurement and interpretation of current transmission in a crossed-field diode below cutoff

    International Nuclear Information System (INIS)

    Vanderberg, B.H.; Eninger, J.E.

    1997-01-01

    Measurements on the current-voltage-magnetic field characteristics of a space-charge-limited cylindrical cross-field diode below cutoff are presented. The measured current is found to be lower than predicted by simple cold-fluid theory. This reduction combined with observed oscillations in the current can be explained by secondary electron emission from the anode, leading to an increase of space charge in the diode. copyright 1997 American Institute of Physics

  14. Measurement

    NARCIS (Netherlands)

    Boumans, M.; Durlauf, S.N.; Blume, L.E.

    2008-01-01

    Measurement theory takes measurement as the assignment of numbers to properties of an empirical system so that a homomorphism between the system and a numerical system is established. To avoid operationalism, two approaches can be distinguished. In the axiomatic approach it is asserted that if the

  15. Measurement of quasi-static and low frequency electric fields on the Viking satellite

    International Nuclear Information System (INIS)

    Block, L.P.; Faelthammar, C.G.; Lindqvist, P.A.; Marklund, G.T.; Mozer, F.S.; Pedersen, A.

    1987-03-01

    The instrument for measurement of quasi-static and low frequency (dc and slow varying) electric fields on the Viking satellite is described. The instrument uses three spherical probe pairs to measure the full three-dimensional electric field vector with 18.75 ms time resolution. The probes are kept near plasma potential by means of a controllable bias current. A guard covering part of the booms is biased to a negative voltage to prevent photoelectrons escaping from the probes from reaching the satellite body. Current-voltage sweeps are performed to determine the plasma density and temperature and to select the optimal bias current. The bias currents to the probes and the voltage offset on the guards as well as the current-voltage sweeps are controlled by an on-board microprocessor which can be programmed from the ground and allows great flexibility. (authors)

  16. Spin correlation and entanglement detection in Cooper pair splitters by current measurements using magnetic detectors

    Science.gov (United States)

    Busz, Piotr; Tomaszewski, Damian; Martinek, Jan

    2017-08-01

    We analyze a model of a double quantum dot Cooper pair splitter coupled to two ferromagnetic detectors and demonstrate the possibility of determination of spin correlation by current measurements. We use perturbation theory, taking account of the exchange interaction with the detectors, which leads to complex spin dynamics in the dots. This affects the measured spin and restricts the use of ferromagnetic detectors to the nonlinear current-voltage characteristic regime at the current plateau, where the relevant spin projection is conserved, in contrast to the linear current-voltage characteristic regime, in which the spin information is distorted. Moreover, we show that for separable states the spin correlation can only be determined in a limited parameter regime, much more restricted than in the case of entangled states. We propose an entanglement test based on the Bell inequality.

  17. Measurements of temperature characteristics and estimation of terahertz negative differential conductance in resonant-tunneling-diode oscillators

    Directory of Open Access Journals (Sweden)

    M. Asada

    2017-11-01

    Full Text Available The temperature dependences of output power, oscillation frequency, and current-voltage curve are measured for resonant-tunneling-diode terahertz (THz oscillators. The output power largely changes with temperature owing to the change in Ohmic loss. In contrast to the output power, the oscillation frequency and current-voltage curve are almost insensitive to temperature. The measured temperature dependence of output power is compared with the theoretical calculation including the negative differential conductance (NDC as a fitting parameter assumed to be independent of temperature. Very good agreement was obtained between the measurement and calculation, and the NDC in the THz frequency region is estimated. The results show that the absolute values of NDC in the THz region significantly decrease relative to that at DC, and increases with increasing frequency in the measured frequency range.

  18. In situ measurement of fixed charge evolution at silicon surfaces during atomic layer deposition

    International Nuclear Information System (INIS)

    Ju, Ling; Watt, Morgan R.; Strandwitz, Nicholas C.

    2015-01-01

    Interfacial fixed charge or interfacial dipoles are present at many semiconductor-dielectric interfaces and have important effects upon device behavior, yet the chemical origins of these electrostatic phenomena are not fully understood. We report the measurement of changes in Si channel conduction in situ during atomic layer deposition (ALD) of aluminum oxide using trimethylaluminum and water to probe changes in surface electrostatics. Current-voltage data were acquired continually before, during, and after the self-limiting chemical reactions that result in film growth. Our measurements indicated an increase in conductance on p-type samples with p + ohmic contacts and a decrease in conductance on analogous n-type samples. Further, p + contacted samples with n-type channels exhibited an increase in measured current and n + contacted p-type samples exhibited a decrease in current under applied voltage. Device physics simulations, where a fixed surface charge was parameterized on the channel surface, connect the surface charge to changes in current-voltage behavior. The simulations and analogous analytical relationships for near-surface conductance were used to explain the experimental results. Specifically, the changes in current-voltage behavior can be attributed to the formation of a fixed negative charge or the modification of a surface dipole upon chemisorption of trimethylaluminum. These measurements allow for the observation of fixed charge or dipole formation during ALD and provide further insight into the electrostatic behavior at semiconductor-dielectric interfaces during film nucleation

  19. Signal transforms in dynamic measurements

    CERN Document Server

    Layer, Edward

    2015-01-01

    This book is devoted to the analysis of measurement signals which requires specific mathematical operations like Convolution, Deconvolution, Laplace, Fourier, Hilbert, Wavelet or Z transform which are all presented in the present book. The different problems refer to the modulation of signals, filtration of disturbance as well as to the orthogonal signals and their use in digital form for the measurement of current, voltage, power and frequency are also widely discussed. All the topics covered in this book are presented in detail and illustrated by means of examples in MathCad and LabVIEW. This book provides a useful source for researchers, scientists and engineers who in their daily work are required to deal with problems of measurement and signal processing and can also be helpful to undergraduate students of electrical engineering.    

  20. Measuring $\

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Jessica Sarah [Univ. of Cambridge (United Kingdom)

    2011-01-01

    The MINOS Experiment consists of two steel-scintillator calorimeters, sampling the long baseline NuMI muon neutrino beam. It was designed to make a precise measurement of the ‘atmospheric’ neutrino mixing parameters, Δm2 atm. and sin2 (2 atm.). The Near Detector measures the initial spectrum of the neutrino beam 1km from the production target, and the Far Detector, at a distance of 735 km, measures the impact of oscillations in the neutrino energy spectrum. Work performed to validate the quality of the data collected by the Near Detector is presented as part of this thesis. This thesis primarily details the results of a vμ disappearance analysis, and presents a new sophisticated fitting software framework, which employs a maximum likelihood method to extract the best fit oscillation parameters. The software is entirely decoupled from the extrapolation procedure between the detectors, and is capable of fitting multiple event samples (defined by the selections applied) in parallel, and any combination of energy dependent and independent sources of systematic error. Two techniques to improve the sensitivity of the oscillation measurement were also developed. The inclusion of information on the energy resolution of the neutrino events results in a significant improvement in the allowed region for the oscillation parameters. The degree to which sin2 (2θ )= 1.0 could be disfavoured with the exposure of the current dataset if the true mixing angle was non-maximal, was also investigated, with an improved neutrino energy reconstruction for very low energy events. The best fit oscillation parameters, obtained by the fitting software and incorporating resolution information were: | Δm2| = 2.32+0.12 -0.08×10-3 eV2 and sin2 (2θ ) > 0.90(90% C.L.). The analysis provides the current world best measurement of the atmospheric neutrino mass

  1. Hlukové emise při výrobě a zpracování objemových krmiv

    OpenAIRE

    ZLOCH, Jan

    2016-01-01

    The main aim of this thesis is to determine noise levels at a certain distance from individual machines of haylage line and working place of operator. While the literary part of the thesis is mainly focused on current technology and a technique used in harvesting of roughage and familiarization with the problems of noise. Practical part of the thesis is focused on characteristics of observed haylage line, measurement of noise levels at a certain distance and in working place of operator with ...

  2. Examinations of a tracer's kinetic behaviour to determine the intermediate lipid metabolism of growing pigs using the slow infusion technique (i.v.)

    International Nuclear Information System (INIS)

    Ruehe, F.

    1982-01-01

    A method is described for in vivo measurements of lipolysis in feeder pigs, which were carried out daily in fasting animals as well as after food intake. The examinations were performed on 8 animals from a backcross strain (Deutsche Landrasse - Deutsches Edelschwein - Deutsche Landrasse, in that order), the bodyweights of which varied between 43 and 53 kg. One hour after having been offered food in the morning or following 16 hours of fasting during the night, four animals were in each case subjected to a 3-hour infusion treatment with 14 C-labelled palmitic acid and parallel blood sampling procedures. The transformation of body fat into free fatty acids circulating in the plasma (lipolysis) and the resynthetisation of those free fatty acids, which leads to the formation of hepatic triglycerides, was then ascertained on the basis of a suitable kinetic model. (orig./MG) [de

  3. Trofiske skift og fysiske faktorer i væksten hos Færøske torsk (Gadus morhua) undersøgt ved brug af stabile isotoper

    DEFF Research Database (Denmark)

    Munk-Nielsen, Jens; Christensen, Jens Tang; Grønkjær, P.

    Projektets formål er at forstå variationen i vækst hos torsk (Gadus Morhua) ved brug af otolither (øresten), og sammenhængen med fysiske faktorer, såsom havstrømme, hav temperatur, osv på den Færøske shelf. Dette undersøges ved hjælp af, 1) en otolith vækst kronologi som dækker mere end 60 år (1948...... en mindre amplitude i variationen af ringbredde end direkte vækst målinger. Over hele vækstkronologien ses en negativ udvikling i væksten hos torsk, dog afbrudt af kortere perioder med positiv vækst. De stabile isotop prøver udtages fra hele otolitter fra 5 år gamle torsk. Fra protein delen af...... omgivelser torsken har oplevet, især den omgivende temperatur. Karbon signalet fra den uorganiske del af otolitten vil blive sammenlignet med værdierne i protein delen. De stabile isotop-værdier, samt vækst data vil blive analyseret for at se sammenhængen mellem klimaet og væksten hos torsk. Både lokalt, med...

  4. Time-resolved ion flux and impedance measurements for process characterization in reactive high-power impulse magnetron sputtering

    Czech Academy of Sciences Publication Activity Database

    Lundin, D.; Čada, Martin; Hubička, Zdeněk

    2016-01-01

    Roč. 34, č. 4 (2016), 1-10, č. článku 041305. ISSN 0734-2101 R&D Projects: GA ČR(CZ) GA15-00863S EU Projects: European Commission(XE) 608800 - HIPPOCAMP Institutional support: RVO:68378271 Keywords : radiofrequency current * voltage measurements * energy-distributions * sheath voltages * deposition * density * hysteresis * discharges * films * technology Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.374, year: 2016

  5. Safety and clinical effect of i.v. infusion of cyclopropyl-methoxycarbonyl etomidate (ABP-700), a soft analogue of etomidate, in healthy subjects.

    Science.gov (United States)

    Valk, B I; Absalom, A R; Meyer, P; Meier, S; den Daas, I; van Amsterdam, K; Campagna, J A; Sweeney, S P; Struys, M M R F

    2018-06-01

    Cyclopropyl-methoxycarbonyl metomidate, or ABP-700, is a second generation analogue of etomidate, developed to retain etomidate's beneficial haemodynamic and respiratory profile but diminishing its suppression of the adrenocortical axis. The objective of this study was to characterise the safety and efficacy of 30-min continuous infusions of ABP-700, and to assess its effect on haemodynamics and the adrenocortical response in healthy human volunteers. Five cohorts involving 40 subjects received increasing infusion doses of ABP-700, propofol 60 μg kg -1  min -1 or placebo. Safety was evaluated through adverse event (AE) monitoring, safety laboratory tests, and arterial blood gasses. Haemodynamic and respiratory stability were assessed by continuous monitoring. Adrenocortical function was analysed by adrenocorticotropic hormone (ACTH) stimulation tests. Clinical effect was measured using the modified observer's assessment of alertness/sedation (MOAA/S) and continuous bispectral index monitoring. No serious AEs were reported. Haemodynamic and respiratory effects included mild dose-dependent tachycardia, slightly elevated blood pressure, and no centrally mediated apnoea. Upon stimulation with ACTH, no adrenocortical depression was observed in any subject. Involuntary muscle movements (IMM) were reported, which were more extensive with higher dosing regimens. Higher dosages of ABP-700 were associated with deeper sedation and increased likelihood of sedation. Time to onset of clinical effect was variable throughout the cohorts and recovery was swift. Infusions of ABP-700 showed a dose-dependent hypnotic effect, and did not cause severe hypotension, severe respiratory depression, or adrenocortical suppression. The presentation and nature of IMM is a matter of concern. NTR4735. Copyright © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.

  6. Strong composition dependence of resistive switching in Ba1-xSrxTiO3 thin films on semiconducting substrates and its thermodynamic analysis

    OpenAIRE

    Mohammad Moradi, Omid; Şen, Canhan; Sen, Canhan; Boni, A. G.; Pintilie, L.; Mısırlıoğlu, Burç; Misirlioglu, Burc

    2018-01-01

    In this work, we report on the variability of the Schottky effect in solution processed Ba1-xSrxTiO3 films (BST, x = 0, 0.5) grown on 0.5% Nb doped SrTiO3 substrates with top Pt electrodes (NSTO/BST/Pt). The films display leakage currents accompanied by varying degrees of hystereses in the current-voltage measurements. The magnitude of the leakage and hystereses depend on the Sr content. We focus on the current-voltage (I-V) behavior of our samples in the light of thermodynamic theory of ferr...

  7. Tagahoovi elluäratamine : TTÜ Kuressaare kolledži väikelaevaehituse kompetentsikeskus = Awakening a backyard to new life : The ship model testing basin for the Tallinn University of Technology`s Small Craft Competence Centre in Kuressaare / Hanne

    Index Scriptorium Estoniae

    Koppel, Hannes

    2014-01-01

    TTÜ Kuressaare kolledži väikelaevaehituse kompetentsikeskuse katsebasseinihoone arhitektuurist. Arhitektid: Aet Ader, Mari Hunt, Kadri Klementi, Kalle Komissarov, Lembit-Laur Stöör. Projekt: 2011-2014. Valmis: 2014

  8. Rating PV Power and Energy: Cell, Module, and System Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, Keith

    2016-06-02

    A summary of key points related to research-level measurements of current vs. voltage measurement theory including basic PV operation, equivalent circuit, and concept of spectral error; PV power performance including PV irradiance sensors, simulators and commercial and generic I-V systems; PV measurement artifacts, intercomparisons, and alternative rating methods.

  9. DESARROLLO DE UN SISTEMA DE CONTROL PARA LA CAPTURA Y MEDICIÓN EXPERIMENTAL DE LA EFICIENCIA Y CURVA CARACTERÍSTICA I-V EN TIEMPO REAL DE UN SISTEMA FOTOVOLTAICO UTILIZANDO LABVIEW® Y ARDUINO

    Directory of Open Access Journals (Sweden)

    Juan Pablo Vargas Bautista

    2015-07-01

    Full Text Available En el presente artículo se presenta un sistema de control para la visualización en tiempo real de datos experimentales de la curva de eficiencia y de la curva característica I-V (corriente versus voltaje de un panel fotovoltaico (FV SUNTECH-STP030-12. El sistema está compuesto de un programa desarrollado en LabView® y un circuito electrónico de captura y procesamiento de datos.  Se utilizó un microprocesador Arduino UNO R3 para la interface entre los datos del panel FV y el programa en LabView®.  Los resultados muestran que es posible utilizar microprocesadores de bajo costo con suficiente capacidad de procesamiento en tiempo real de la información obtenida de los paneles FV.

  10. Hram viden i v notshi... / Jevgeni Ashihmin

    Index Scriptorium Estoniae

    Ashihmin, Jevgeni

    2006-01-01

    Narva Ülestõusmise kirik (arhitekt Paul Alisch) saab 110. aastapäevaks fassaadi valgustuse. Projekti autorid Peterburi firmast "Tehnosvet". Kirikule aastapäevaks kingitud keraamilisest pannoost, ikoonidest

  11. V tesnote i v obide / Jekaterina Rodina

    Index Scriptorium Estoniae

    Rodina, Jekaterina

    2005-01-01

    EA Reng arhitekti Ilmar Jalase koostatud detailplaneering näeb ette Tallinna Õismäe elamurajoonis Paldiski mnt. 227 / Järveotsa tee 2 vahele 24, 14- ja 9-korruseliste hoonete ehitamist. Elanike protest peatas 24-korruselise elumaja planeeringu kinnitamise

  12. Golossa optom i v roznitsu / Josef Kats

    Index Scriptorium Estoniae

    Kats, Josef, 1977-

    2005-01-01

    Eelhääletuse käigus ilmsiks tulnud katsed hääli kokku osta, ei tohi valimiste ega elektroonilise hääletamise tulemusi kahtluse alla seada, justiitsminister Rein Langi esinemisest valitsuse pressikonverentsil

  13. Rousseau i våre hjerter

    Directory of Open Access Journals (Sweden)

    Lars Løvlie

    2013-09-01

    Full Text Available This essay broaches pedagogical key themes in Rousseau’s writings, primarily sourced from Émile, a book that 250 years after its first publication offers up a strikingly relevant critique of the current neo-liberal politics of schooling in the Western world. Rousseau was a keen observer of human folly, a sharp critic of Enlightenment culture, and an imaginative author with an acute sense of the vagaries of mind and feeling. I recount how he treats feelings, particularly the inner voice of conscience, as a core element in education. His idea of “negative pedagogy” is a lasting contribution to educational thinking in general and highly relevant for our discussion today about self-regulation and discipline in education. Rousseau’s idea about authenticity leads directly to the question of individual character and the relation between self-love and amour-propre. Here we are presented to a positive pedagogy, which is to foster the first and to foil the second. After having touched the conflict between theory and practice in Rousseau’s own life, I observe that the woman in Émile’s life, Sophie, comes forth as naturally healthy person, fit to face society’s temptations, while Émile in comparison must be protected from its harms by his well-meaning tutor until he turns 15. In a longer section I present the pedagogical paradox, which says that you cannot force a child to be independent. Rousseau interestingly disregards the paradox, which seems to cast doubt on his reputation as a radical reformer of modern pedagogy.

  14. Rousseau i våre hjerter

    Directory of Open Access Journals (Sweden)

    Lars Løvlie

    2013-09-01

    Full Text Available This essay broaches pedagogical key themes in Rousseau’s writings, primarily sourced from Émile, a book that 250 years after its first publication offers up a strikingly relevant critique of the current neo-liberal politics of schooling in the Western world. Rousseau was a keen observer of human folly, a sharp critic of Enlightenment culture, and an imaginative author with an acute sense of the vagaries of mind and feeling. I recount how he treats feelings, particularly the inner voice of conscience, as a core element in education. His idea of “negative pedagogy” is a lasting contribution to educational thinking in general and highly relevant for our discussion today about self-regulation and discipline in education. Rousseau’s idea about authenticity leads directly to the question of individual character and the relation between self-love and amour-propre. Here we are presented to a positive pedagogy, which is to foster the first and to foil the second. After having touched the conflict between theory and practice in Rousseau’s own life, I observe that the woman in Émile’s life, Sophie, comes forth as naturally healthy person, fit to face society’s temptations, while Émile in comparison must be protected from its harms by his well-meaning tutor until he turns 15. In a longer section I present the pedagogical paradox, which says that you cannot force a child to be independent. Rousseau interestingly disregards the paradox, which seems to cast doubt on his reputation as a radical reformer of modern pedagogy.  

  15. Plasma diagnosis of RF discharge by using impedance measurement

    International Nuclear Information System (INIS)

    Huang Jianjun; Teuner, D.

    2001-01-01

    It is presented that the method known from network analysis with home-made probe and experimental setup to measure current, voltage and phase angle of RF discharge in He gas more accurately. The sheath thickness and the real and imaginary parts of the plasma impedance were obtained by using the equivalent circuit model and taking account stray capacitances of the set-up. In addition, making use of Godyak's RF discharge simple model, the electron density in the discharge was calculated at different pressure and current density

  16. Superconducting phonon spectroscopy using a low-temperature scanning tunneling microscope

    Science.gov (United States)

    Leduc, H. G.; Kaiser, W. J.; Hunt, B. D.; Bell, L. D.; Jaklevic, R. C.

    1989-01-01

    The low-temperature scanning tunneling microscope (STM) system described by LeDuc et al. (1987) was used to observe the phonon density of states effects in a superconductor. Using techniques based on those employed in macroscopic tunneling spectroscopy, electron tunneling current-voltage (I-V) spectra were measured for NbN and Pb, and dI/dV vs V spectra were measured using standard analog derivative techniques. I-V measurements on NbN and Pb samples under typical STM conditions showed no evidence for multiparticle tunneling effects.

  17. Využití metodiky RUP při vývoji webové aplikace menšího rozsahu v prostředí PHP 5

    OpenAIRE

    Albrecht, Jakub

    2008-01-01

    Práce se snaží zhodnotit možnosti využití metodiky RUP při realizaci projektu vývoje konkrétního informačního systému s danými parametry. Těmito parametry jsou malý rozsah, webová platforma a technologické prostředí PHP 5. V úvodu se práce zaobírá úlohou metodik při vývoji software, následuje představení metodiky RUP. Dále je probírána metodická podpora specifických charakteristik projektů. Vlastním přínosem práce je vytvoření vlastní instance metodiky RUP vhodné pro definovaný projekt a na z...

  18. Uranium metalla-allenes with carbene imido R_2C=U"I"V=NR' units (R=Ph_2PNSiMe_3; R'=CPh_3): alkali-metal-mediated push-pull effects with an amido auxiliary

    International Nuclear Information System (INIS)

    Lu, Erli; Tuna, Floriana; Kaltsoyannis, Nikolas; Liddle, Stephen T.; Lewis, William

    2016-01-01

    We report uranium(IV)-carbene-imido-amide metalla-allene complexes [U(BIPM"T"M"S)(NCPh_3)(NHCPh_3)(M)] (BIPM"T"M"S=C(PPh_2NSiMe_3)_2; M=Li or K) that can be described as R_2C=U=NR' push-pull metalla-allene units, as organometallic counterparts of the well-known push-pull organic allenes. The solid-state structures reveal that the R_2C=U=NR' units adopt highly unusual cis-arrangements, which are also reproduced by gas-phase theoretical studies conducted without the alkali metals to remove their potential structure-directing roles. Computational studies confirm the double-bond nature of the U=NR' and U=CR_2 interactions, the latter increasingly attenuated by potassium then lithium when compared to the hypothetical alkali-metal-free anion. Combined experimental and theoretical data show that the push-pull effect induced by the alkali metal cations and amide auxiliary gives a fundamental and tunable structural influence over the C=U"I"V=N units. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. A first comparison of irregularity and ion drift velocity measurements in the E-region

    Directory of Open Access Journals (Sweden)

    R. A. Makarevich

    2006-09-01

    Full Text Available E-region irregularity velocity measurements at large flow angles with the STARE Finland coherent VHF radar are considered in context of the ion and electron velocity data provided by the EISCAT tristatic radar system, CUTLASS Finland coherent HF radar, and IMAGE fluxgate magnetometers. The data have been collected during a special experiment on 27 March 2004 during which EISCAT was scanning between several E- and one F-region altitudes along the magnetic field line. Within the E-region, the EISCAT measurements at two altitudes of 110 and 115 km are considered while the electron velocity is inferred from the EISCAT ion velocity measurements at 278 km. The line-of-sight (l-o-s VHF velocity measured by STARE VHF los is compared to the ion and electron velocity components (<i>Vi0 comp and <i>Ve0 comp along the STARE l-o-s direction. The comparison with <i>Ve0 comp for the entire event shows that the measurements exhibit large scatter and small positive correlation. The correlation with <i>Ve0 comp was substantial in the first half of the interval under study when <i>Ve0 comp was larger in magnitude. The comparison with <i>Vi0 comp at 110 and 115 km shows a considerable positive correlation, with VHF velocity being typically larger (smaller in magnitude than <i>Vi0 comp at 110 km (115 km so that <i>VVHF los appears to be bounded by the ion velocity components at two altitudes. It is also demonstrated that the difference between <i>VVHF los and <i>Vi0 comp at 110 km can be treated, in the first approximation, as a linear function of the effective backscatter height heff also counted from 110 km; heff varies in the range 108–114 km due to the altitude integration effects in the scattering cross-section. Our results are consistent with the notion that VHF

  20. Measurement of mismatch loss in CPV modul

    Science.gov (United States)

    Liu, Mingguo; Kinsey, Geoffrey S.; Bagienski, Will; Nayak, Adi; Garboushian, Vahan

    2012-10-01

    A setup capable of simultaneously measuring I-V curves of a full string and its individual cells has been developed. This setup enables us to measure mismatch loss from individual cells in concert with various string combinations under varying field conditions. Mismatch loss from cells to plates at different off-track angles and mismatch from plates to strings in Amonix system during normal operation have been investigated.

  1. Physical Mechanisms Responsible for Electrical Conduction in Pt/GaN Schottky Diodes

    OpenAIRE

    H. MAZARI; K. AMEUR; N. BENSEDDIK; Z. BENAMARA; R. KHELIFI; M. MOSTEFAOUI; N. ZOUGAGH; N. BENYAHYA; R. BECHAREF; G. BASSOU; B. GRUZZA; J. M. BLUET; C. BRU-CHEVALLIER

    2014-01-01

    The current-voltage (I-V) characteristics of Pt/(n.u.d)-GaN and Pt/Si-doped-GaN diodes Schottky are investigated. Based on these measurements, physical mechanisms responsible for electrical conduction have been suggested. The contribution of thermionic-emission current and various other current transport mechanisms were assumed when evaluating the Schottky barrier height. Thus the generation-recombination, tunneling and leakage currents caused by inhomogeneities and defects at metal-semicondu...

  2. Estimating Parameters for the PVsyst Version 6 Photovoltaic Module Performance Model

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Clifford [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-10-01

    We present an algorithm to determine parameters for the photovoltaic module perf ormance model encoded in the software package PVsyst(TM) version 6. Our method operates on current - voltage (I - V) measured over a range of irradiance and temperature conditions. We describe the method and illustrate its steps using data for a 36 cell crystalli ne silicon module. We qualitatively compare our method with one other technique for estimating parameters for the PVsyst(TM) version 6 model .

  3. The addition of tramadol to the standard of i.v. acetaminophen and morphine infusion for postoperative analgesia in neonates offers no clinical benefit: a randomized placebo-controlled trial.

    Science.gov (United States)

    Olischar, Monika; Palmer, Greta M; Orsini, Francesca; Davidson, Andrew J; Perkins, Elizabeth J; Lee, Katherine J; Everest, Neil J; Cranswick, Noel E; Hunt, Rod W

    2014-11-01

    Tramadol is used following neonatal cardiac and general surgery. However, its ability to opioid-spare or facilitate earlier extubation in postoperative neonates is unquantified. This randomized placebo-controlled trial aimed to assess whether tramadol's addition to standard analgesia resulted in earlier extubation or reduced analgesic/sedative requirements in postsurgical neonates. Neonates born ≥32 weeks postmenstrual age received either tramadol [T] 2 mg·kg(-1) or placebo [P] 6-hourly for up to 5 days postthoracoabdominal surgery in addition to morphine (commenced at 20 mcg·kg(-1) ·h(-1)) and 6-hourly i.v. acetaminophen. Time to extubation, morphine and midazolam amounts, hourly pain scores, and seizure activity were compared using an intention-to-treat and per-protocol analysis. Seventy-one neonates participated. Median survival time to extubation was similar between the groups (T 67 h [95% CI 51, 84] vs P 52 h [95%CI 43, 65]; P = 0.4), and similar numbers were extubated by 96 h (T 69% vs P 77%; difference -8%, 95%CI -28, 13%). Morphine and midazolam exposure was similar, with low pain scores in both groups (mean percentage of time with a pain score >5/20 during the 5 days: T 13% vs P 11%, difference in means 2.8 [95% CI -1.8, 7.6], P = 0.20). Most participants had normal cranial ultrasounds (T 86% vs P 86%); no seizures occurred clinically or electroencephalographically. Tramadol's addition to standard analgesia in this small group of postsurgical neonates did not appear to have any positive effect on time to extubation, morphine or midazolam exposure, or pain scores. This questions the benefit of tramadol for postsurgical neonates. Importantly, no seizures occurred in these ill neonates who may potentially be at greater risk of tramadol toxicity compared with adults. © 2014 John Wiley & Sons Ltd.

  4. Experimental Study of Hydroxy Gas (HHO) Production with Variation in Current, Voltage and Electrolyte Concentration

    Science.gov (United States)

    Alam, Noor; Pandey, K. M.

    2017-08-01

    In this paper, work has been carried out experimentally for the investigation of the effects of variation incurrent, voltage, temperature, chemical concentration and reaction time on the amount of hydroxy gas produced. Further effects on the overall electrolysis efficiency of advance alkaline water is also studied. The hydroxy gas (HHO) has been produced experimentally by the electrolysis of alkaline water with parallel plate electrode of 316L-grade stainless steel. The electrode has been selected on the basis of corrosion resistance and inertness with respect to electrolyte (KOH). The process used for the production of HHO is conventional as compared to the other production processes because of reduced energy consumption, less maintenance and low setup cost. From the experimental results, it has been observed that with increase in voltage, temperature and electrolyte concentration of alkaline solution, the production of hydroxy gas has increased about 30 to 40% with reduction in electrical energy consumption.

  5. Determination of the internal parameters of tc from the current-voltage characteristics

    International Nuclear Information System (INIS)

    Kaibyshev, V.Z.

    1986-01-01

    This paper proposes a method for determining the effective work function of a collector, the electron temperature, and the voltage drop in the interelectrode gap from the experimental vurrent-voltage characteristics (IVC). Analysis of the boundary conditions at the collector shows that as the emission from the collector increases the height of the potential jump retarding plasma electrons decrease

  6. Current-voltage characteristics of a gas field ion source with a supertip

    International Nuclear Information System (INIS)

    Boerret, R.; Boehringer, K.; Kalbitzer, S.

    1990-01-01

    The field ionisation properties of a supertip, a fine protrusion on top of a regular emitter, have been studied for hydrogen and the lighter rare gases. The parameter set included tip temperature, tip radius, gas temperature and gas pressure. Due to the local field enhancement at the supertip site, angular current intensities of 35 μA sr -1 and values of brightness up to 10 10 A cm -2 sr -1 have been obtained near the optimum temperature of the gas-tip system. At temperatures below this, the gas density reaches values typical for a condensed phase. In geometrical proportion, the regular tip area appears to serve as a gas supply for the supertip current. (author)

  7. Thermal instability and current-voltage scaling in superconducting fault current limiters

    Energy Technology Data Exchange (ETDEWEB)

    Zeimetz, B [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Tadinada, K [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Eves, D E [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Coombs, T A [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom); Evetts, J E [Department of Materials Science and Metallurgy, Cambridge University, Pembroke Street, Cambridge CB1 3QZ (United Kingdom); Campbell, A M [Department of Engineering, Cambridge University, Trumpington Road, Cambridge CB2 1PZ (United Kingdom)

    2004-04-01

    We have developed a computer model for the simulation of resistive superconducting fault current limiters in three dimensions. The program calculates the electromagnetic and thermal response of a superconductor to a time-dependent overload voltage, with different possible cooling conditions for the surfaces, and locally variable superconducting and thermal properties. We find that the cryogen boil-off parameters critically influence the stability of a limiter. The recovery time after a fault increases strongly with thickness. Above a critical thickness, the temperature is unstable even for a small applied AC voltage. The maximum voltage and maximum current during a short fault are correlated by a simple exponential law.

  8. Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

    Energy Technology Data Exchange (ETDEWEB)

    Venkattraman, Ayyaswamy [Department of Applied Mechanics, Indian Institute of Technology Madras, Chennai 600036 (India)

    2013-11-15

    The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission.

  9. Luminescence evolution from alumina ceramic surface before flashover under direct and alternating current voltage in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Su, Guo-Qiang; Wang, Yi-Bo; Song, Bai-Peng; Mu, Hai-Bao, E-mail: haibaomu@xjtu.edu.cn, E-mail: gjzhang@xjtu.edu.cn; Zhang, Guan-Jun, E-mail: haibaomu@xjtu.edu.cn, E-mail: gjzhang@xjtu.edu.cn [State Key Laboratory of Electrical Insulation and Power Equipment, School of Electrical Engineering, Xi’an Jiaotong University, Xi’an, Shaanxi 710049 (China); Li, Feng; Wang, Meng [Institute of Fluid Physics, China Academy of Engineering Physics, Mianyang, Sichuan 621900 (China)

    2016-06-15

    The luminescence evolution phenomena from alumina ceramic surface in vacuum under high voltage of direct and alternating current are reported, with the voltage covering a large range from far below to close to the flashover voltage. Its time resolved and spatial distributed behaviors are examined by a photon counting system and an electron-multiplying charge-coupled device (EMCCD) together with a digital camera, respectively. The luminescence before flashover exhibits two stages as voltage increasing, i.e., under a relative low voltage (Stage A), the luminescence is ascribed to radiative recombination of hetero-charges injected into the sample surface layer by Schottky effect; under a higher voltage (Stage B), a stable secondary electron emission process, resulting from the Fowler-Nordheim emission at the cathode triple junction (CTJ), is responsible for the luminescence. Spectrum analysis implies that inner secondary electrons within the surface layer of alumina generated during the SSEE process also participate in the luminescence of Stage B. A comprehensive interpretation of the flashover process is formulated, which might promote a better understanding of flashover issue in vacuum.

  10. Implementation of an active instructional design for teaching the concepts of current, voltage and resistance

    Science.gov (United States)

    Orlaineta-Agüero, S.; Del Sol-Fernández, S.; Sánchez-Guzmán, D.; García-Salcedo, R.

    2017-01-01

    In the present work we show the implementation of a learning sequence based on an active learning methodology for teaching Physics, this proposal tends to promote a better learning in high school students with the use of a comic book and it combines the use of different low-cost experimental activities for teaching the electrical concepts of Current, Resistance and Voltage. We consider that this kind of strategy can be easily extrapolated to higher-education levels like Engineering-college/university level and other disciplines of Science. To evaluate this proposal, we used some conceptual questions from the Electric Circuits Concept Evaluation survey developed by Sokoloff and the results from this survey was analysed with the Normalized Conceptual Gain proposed by Hake and the Concentration Factor that was proposed by Bao and Redish, to identify the effectiveness of the methodology and the models that the students presented after and before the instruction, respectively. We found that this methodology was more effective than only the implementation of traditional lectures, we consider that these results cannot be generalized but gave us the opportunity to view many important approaches in Physics Education; finally, we will continue to apply the same experiment with more students, in the same and upper levels of education, to confirm and validate the effectiveness of this methodology proposal.

  11. Current-Voltage Characteristics of Bi-dithiolbenzene in Parallel Arrangement

    International Nuclear Information System (INIS)

    Boudjella, Aissa

    2011-01-01

    The low voltage conductance of interacting two 1,4-dithiolbenzene (DTB) molecules is investigated. The simulation results show that the electron transport can be controlled either by changing the Fermi level position E f or modifying its inter-molecular spacing d. Molecular assembly system with close interaction between DTB units, affects significantly the conductance. In addition, the position of the Fermi plays an important role in determining the current flow. Moreover, it is important to note that E f affects not only the threshold voltage V th , but also the saturation voltage V sat . When E f approaches the LUMO energy level, V th decreases, while V sat increases. To conclude, the threshold voltage and the saturation voltage depend on the Fermi level position and the inter-molecular spacing.

  12. Study on different influence of pyrimidine and phenyl on current-voltage characteristics of molecular devices

    International Nuclear Information System (INIS)

    Fu Xiaoxiao; Li Zongliang

    2011-01-01

    By using ab initio method and elastic scattering Green's function theory, electronic transport properties of symmetric tetraphenyl and non-symmetric diblock dipyrimidinyldiphenyl molecules are investigated. The numerical results show that, the tetraphenyl molecule has better electronic conductivity than the diblock molecule. The diblock molecule exhibits pronounced rectification behavior. Some molecular orbitals of the tetraphenyl molecule are delocalized into the two gold electrodes simultaneously which results in the better electronic conductivity. However, the non-symmetric structure of diblock molecule leads to the localization of the molecular orbitals, which is a disadvantage to the electronic transport. (authors)

  13. Subcell Light Current-Voltage Characterization of Irradiated Multijunction Solar Cell

    Directory of Open Access Journals (Sweden)

    Walker Don

    2017-01-01

    Full Text Available The degradation of individual subcell J-V parameters, such as short circuit current, open circuit voltage, fill factor, and power of a GaInP/GaInAs/Ge triple junction solar cell by 1 MeV electrons were derived utilizing the spectral reciprocity relation between electroluminescence and external quantum efficiency. After exposure to a fluence of 1 × 1015 1 MeV electrons, it was observed that up to 67% of the voltage loss is from the middle, GaInAs subcell. Also, the dark saturation current of the Ge and GaInAs subcells increased but a simultaneous decrease in ideality factor caused a reduction of the open circuit voltage. The reduced ideality factor further indicates a change in the primary recombination mechanism.

  14. Cathode fall model and current-voltage characteristics of field emission driven direct current microplasmas

    International Nuclear Information System (INIS)

    Venkattraman, Ayyaswamy

    2013-01-01

    The post-breakdown characteristics of field emission driven microplasma are studied theoretically and numerically. A cathode fall model assuming a linearly varying electric field is used to obtain equations governing the operation of steady state field emission driven microplasmas. The results obtained from the model by solving these equations are compared with particle-in-cell with Monte Carlo collisions simulation results for parameters including the plasma potential, cathode fall thickness, ion number density in the cathode fall, and current density vs voltage curves. The model shows good overall agreement with the simulations but results in slightly overpredicted values for the plasma potential and the cathode fall thickness attributed to the assumed electric field profile. The current density vs voltage curves obtained show an arc region characterized by negative slope as well as an abnormal glow discharge characterized by a positive slope in gaps as small as 10 μm operating at atmospheric pressure. The model also retrieves the traditional macroscale current vs voltage theory in the absence of field emission

  15. Phonon-assisted tunnelling in electrical conductivity of individual carbon nanotubes and networks ones

    Energy Technology Data Exchange (ETDEWEB)

    Pipinys, P. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania)], E-mail: pipiniai@takas.lt; Kiveris, A. [Department of Physics, Vilnius Pedagogical University, Studentu 39, LT-08106 Vilnius (Lithuania)], E-mail: studsk@vpu.lt

    2008-10-01

    Current-voltage (I-V) characteristics of single-wall carbon nanotubes (SWCNT), measured in the low temperatures by Tang et al. [Science 292 (2001) 2462] and transparent SWCNT networks presented by Jaiswal et al. [J. Phys.: Condens. Matter 19 (2007) 446006], are reinterpreted in the framework of phonon-assisted tunnelling theory as a free charge carriers generation mechanism in the strong electrical field. The good fit of the temperature-dependent I-V data in low temperature region (i.e., T<25 K) has been achieved using the phonons of energy <1 meV.

  16. Phonon-assisted tunnelling in electrical conductivity of individual carbon nanotubes and networks ones

    International Nuclear Information System (INIS)

    Pipinys, P.; Kiveris, A.

    2008-01-01

    Current-voltage (I-V) characteristics of single-wall carbon nanotubes (SWCNT), measured in the low temperatures by Tang et al. [Science 292 (2001) 2462] and transparent SWCNT networks presented by Jaiswal et al. [J. Phys.: Condens. Matter 19 (2007) 446006], are reinterpreted in the framework of phonon-assisted tunnelling theory as a free charge carriers generation mechanism in the strong electrical field. The good fit of the temperature-dependent I-V data in low temperature region (i.e., T<25 K) has been achieved using the phonons of energy <1 meV

  17. Measuring the Electronic Properties of DNA-Specific Schottky Diodes Towards Detecting and Identifying Basidiomycetes DNA

    Science.gov (United States)

    Periasamy, Vengadesh; Rizan, Nastaran; Al-Ta’ii, Hassan Maktuff Jaber; Tan, Yee Shin; Tajuddin, Hairul Annuar; Iwamoto, Mitsumasa

    2016-01-01

    The discovery of semiconducting behavior of deoxyribonucleic acid (DNA) has resulted in a large number of literatures in the study of DNA electronics. Sequence-specific electronic response provides a platform towards understanding charge transfer mechanism and therefore the electronic properties of DNA. It is possible to utilize these characteristic properties to identify/detect DNA. In this current work, we demonstrate a novel method of DNA-based identification of basidiomycetes using current-voltage (I-V) profiles obtained from DNA-specific Schottky barrier diodes. Electronic properties such as ideality factor, barrier height, shunt resistance, series resistance, turn-on voltage, knee-voltage, breakdown voltage and breakdown current were calculated and used to quantify the identification process as compared to morphological and molecular characterization techniques. The use of these techniques is necessary in order to study biodiversity, but sometimes it can be misleading and unreliable and is not sufficiently useful for the identification of fungi genera. Many of these methods have failed when it comes to identification of closely related species of certain genus like Pleurotus. Our electronics profiles, both in the negative and positive bias regions were however found to be highly characteristic according to the base-pair sequences. We believe that this simple, low-cost and practical method could be useful towards identifying and detecting DNA in biotechnology and pathology. PMID:27435636

  18. Scanning tip measurement for identification of point defects

    Directory of Open Access Journals (Sweden)

    Raineri Vito

    2011-01-01

    Full Text Available Abstract Self-assembled iron-silicide nanostructures were prepared by reactive deposition epitaxy of Fe onto silicon. Capacitance-voltage, current-voltage, and deep level transient spectroscopy (DLTS were used to measure the electrical properties of Au/silicon Schottky junctions. Spreading resistance and scanning probe capacitance microscopy (SCM were applied to measure local electrical properties. Using a preamplifier the sensitivity of DLTS was increased satisfactorily to measure transients of the scanning tip semiconductor junction. In the Fe-deposited area, Fe-related defects dominate the surface layer in about 0.5 μm depth. These defects deteriorated the Schottky junction characteristic. Outside the Fe-deposited area, Fe-related defect concentration was identified in a thin layer near the surface. The defect transients in this area were measured both in macroscopic Schottky junctions and by scanning tip DLTS and were detected by bias modulation frequency dependence in SCM.

  19. Statistical MOSFET Parameter Extraction with Parameter Selection for Minimal Point Measurement

    Directory of Open Access Journals (Sweden)

    Marga Alisjahbana

    2013-11-01

    Full Text Available A method to statistically extract MOSFET model parameters from a minimal number of transistor I(V characteristic curve measurements, taken during fabrication process monitoring. It includes a sensitivity analysis of the model, test/measurement point selection, and a parameter extraction experiment on the process data. The actual extraction is based on a linear error model, the sensitivity of the MOSFET model with respect to the parameters, and Newton-Raphson iterations. Simulated results showed good accuracy of parameter extraction and I(V curve fit for parameter deviations of up 20% from nominal values, including for a process shift of 10% from nominal.

  20. Stability Analysis for Li-Ion Battery Model Parameters and State of Charge Estimation by Measurement Uncertainty Consideration

    Directory of Open Access Journals (Sweden)

    Shifei Yuan

    2015-07-01

    Full Text Available Accurate estimation of model parameters and state of charge (SoC is crucial for the lithium-ion battery management system (BMS. In this paper, the stability of the model parameters and SoC estimation under measurement uncertainty is evaluated by three different factors: (i sampling periods of 1/0.5/0.1 s; (ii current sensor precisions of ±5/±50/±500 mA; and (iii voltage sensor precisions of ±1/±2.5/±5 mV. Firstly, the numerical model stability analysis and parametric sensitivity analysis for battery model parameters are conducted under sampling frequency of 1–50 Hz. The perturbation analysis is theoretically performed of current/voltage measurement uncertainty on model parameter variation. Secondly, the impact of three different factors on the model parameters and SoC estimation was evaluated with the federal urban driving sequence (FUDS profile. The bias correction recursive least square (CRLS and adaptive extended Kalman filter (AEKF algorithm were adopted to estimate the model parameters and SoC jointly. Finally, the simulation results were compared and some insightful findings were concluded. For the given battery model and parameter estimation algorithm, the sampling period, and current/voltage sampling accuracy presented a non-negligible effect on the estimation results of model parameters. This research revealed the influence of the measurement uncertainty on the model parameter estimation, which will provide the guidelines to select a reasonable sampling period and the current/voltage sensor sampling precisions in engineering applications.

  1. Measurement and understanding of single-molecule break junction rectification caused by asymmetric contacts

    International Nuclear Information System (INIS)

    Wang, Kun; Zhou, Jianfeng; Hamill, Joseph M.; Xu, Bingqian

    2014-01-01

    The contact effects of single-molecule break junctions on rectification behaviors were experimentally explored by a systematic control of anchoring groups of 1,4-disubstituted benzene molecular junctions. Single-molecule conductance and I-V characteristic measurements reveal a strong correlation between rectifying effects and the asymmetry in contacts. Analysis using energy band models and I-V calculations suggested that the rectification behavior is mainly caused by asymmetric coupling strengths at the two contact interfaces. Fitting of the rectification ratio by a modified Simmons model we developed suggests asymmetry in potential drop across the asymmetric anchoring groups as the mechanism of rectifying I-V behavior. This study provides direct experimental evidence and sheds light on the mechanisms of rectification behavior induced simply by contact asymmetry, which serves as an aid to interpret future single-molecule electronic behavior involved with asymmetric contact conformation

  2. Development of measuring system with self-powered neutron detectors for the LR-0 reactor

    International Nuclear Information System (INIS)

    Erben, O.; Horinek, K.; Szasz, Z.

    1989-01-01

    A measuring channel with self-powered detectors was developed for measuring neutron fluxs density in the reactor core. The measuring channel consists of a measuring probe with standard self-powered detectors of Soviet make, a signal pathway, a current/voltage converter and a measuring and recording unit. Neutron flux density in the LR-0 reactor core reaches a maximum of 10 13 m -2 s -1 . Experiments using the channel were carried out both in steady-state operation and after emergency shutdown of the reactor, this from power levels of 2,096 W and 1,830 W. The results of the experiments are tabulated and briefly analyzed. (Z.M.). 4 figs., 3 tabs., 5 refs

  3. Fabricate heterojunction diode by using the modified spray pyrolysis method to deposit nickel-lithium oxide on indium tin oxide substrate.

    Science.gov (United States)

    Wu, Chia-Ching; Yang, Cheng-Fu

    2013-06-12

    P-type lithium-doped nickel oxide (p-LNiO) thin films were deposited on an n-type indium tin oxide (ITO) glass substrate using the modified spray pyrolysis method (SPM), to fabricate a transparent p-n heterojunction diode. The structural, optical, and electrical properties of the p-LNiO and ITO thin films and the p-LNiO/n-ITO heterojunction diode were characterized by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), UV-visible spectroscopy, Hall effect measurement, and current-voltage (I-V) measurements. The nonlinear and rectifying I-V properties confirmed that a heterojunction diode characteristic was successfully formed in the p-LNiO/n-ITO (p-n) structure. The I-V characteristic was dominated by space-charge-limited current (SCLC), and the Anderson model demonstrated that band alignment existed in the p-LNiO/n-ITO heterojunction diode.

  4. In-Situ Measurement of Power Loss for Crystalline Silicon Modules Undergoing Thermal Cycling and Mechanical Loading Stress Testing

    DEFF Research Database (Denmark)

    Spataru, Sergiu; Hacke, Peter; Sera, Dezso

    We analyze the degradation of multi-crystalline silicon photovoltaic modules undergoing simultaneous thermal, mechanical, and humidity-freeze stress testing to develop a dark environmental chamber in-situ measurement procedure for determining module power loss. We analyze dark I-V curves measured...

  5. Gap enhancement in phonon-irradiated superconducting tin films

    International Nuclear Information System (INIS)

    Miller, N.D.; Rutledge, J.E.

    1982-01-01

    We have measured the current-voltage (I-V) characteristics of tin-tin tunnel junctions driven out of equilibrium by a flux of near-thermal phonons from a heater. The reduced ambient temperature was T/T/sub c/ = 0.41. The nonequilibrium I-V curves are compared to equilibrium thermal I-V curves at an elevated temperature chosen to match the total number of quasiparticles. The nonequilibrium curves show a smaller current near zero bias and a larger gap than the thermal curves. This is the first experimental evidence of phonon-induced gap enhancement far below T/sub c/. The results are discussed in terms of the coupled kinetic equations of Chang and Scalapino

  6. Understanding Pt-ZnO:In Schottky nanocontacts by conductive atomic force microscopy

    Science.gov (United States)

    Chirakkara, Saraswathi; Choudhury, Palash Roy; Nanda, K. K.; Krupanidhi, S. B.

    2016-04-01

    Undoped and In doped ZnO (IZO) thin films are grown on Pt coated silicon substrates Pt/Si by pulsed laser deposition to fabricate Pt/ZnO:In Schottky diodes. The Schottky diodes were investigated by conventional two-probe current-voltage (I-V) measurements and by the I-V spectroscopy tool of conductive atomic force microscopy (C-AFM). The large deviation of the ideality factor from unity and the temperature dependent Schottky barrier heights (SBHs) obtained from the conventional method imply the presence of inhomogeneous interfaces. The inhomogeneity of SBHs is confirmed by C-AFM. Interestingly, the I-V curves at different points are found to be different, and the SBHs deduced from the point diodes reveal inhomogeneity at the nanoscale at the metal-semiconductor interface. A reduction in SBH and turn-on voltage along with enhancement in forward current are observed with increasing indium concentration.

  7. The Schottky energy barrier dependence of charge injection in organic light-emitting diodes

    Science.gov (United States)

    Campbell, I. H.; Davids, P. S.; Smith, D. L.; Barashkov, N. N.; Ferraris, J. P.

    1998-04-01

    We present device model calculations of the current-voltage (I-V) characteristics of organic diodes and compare them with measurements of structures fabricated using MEH-PPV. The structures are designed so that all of the current is injected from one contact. The I-V characteristics are considered as a function of the Schottky energy barrier to charge injection from the contact. Experimentally, the Schottky barrier is varied from essentially zero to more than 1 eV by using different metal contacts. A consistent description of the device I-V characteristics is obtained as the Schottky barrier is varied from small values, less than about 0.4 eV, where the current flow is space-charge limited to larger values where it is contact limited.

  8. Ultralarge area MOS tunnel devices for electron emission

    DEFF Research Database (Denmark)

    Thomsen, Lasse Bjørchmar; Nielsen, Gunver; Vendelbo, Søren Bastholm

    2007-01-01

    density. Oxide thicknesses have been extracted by fitting a model based on Fermi-Dirac statistics to the C-V characteristics. By plotting I-V characteristics in a Fowler plot, a measure of the thickness of the oxide can be extracted from the tunnel current. These apparent thicknesses show a high degree......A comparative analysis of metal-oxide-semiconductor (MOS) capacitors by capacitance-voltage (C-V) and current-voltage (I-V) characteristics has been employed to characterize the thickness variations of the oxide on different length scales. Ultralarge area (1 cm(2)) ultrathin (similar to 5 nm oxide......) MOS capacitors have been fabricated to investigate their functionality and the variations in oxide thickness, with the use as future electron emission devices as the goal. I-V characteristics show very low leakage current and excellent agreement to the Fowler-Nordheim expression for the current...

  9. A fully automated temperature-dependent resistance measurement setup using van der Pauw method

    Science.gov (United States)

    Pandey, Shivendra Kumar; Manivannan, Anbarasu

    2018-03-01

    The van der Pauw (VDP) method is widely used to identify the resistance of planar homogeneous samples with four contacts placed on its periphery. We have developed a fully automated thin film resistance measurement setup using the VDP method with the capability of precisely measuring a wide range of thin film resistances from few mΩ up to 10 GΩ under controlled temperatures from room-temperature up to 600 °C. The setup utilizes a robust, custom-designed switching network board (SNB) for measuring current-voltage characteristics automatically at four different source-measure configurations based on the VDP method. Moreover, SNB is connected with low noise shielded coaxial cables that reduce the effect of leakage current as well as the capacitance in the circuit thereby enhancing the accuracy of measurement. In order to enable precise and accurate resistance measurement of the sample, wide range of sourcing currents/voltages are pre-determined with the capability of auto-tuning for ˜12 orders of variation in the resistances. Furthermore, the setup has been calibrated with standard samples and also employed to investigate temperature dependent resistance (few Ω-10 GΩ) measurements for various chalcogenide based phase change thin films (Ge2Sb2Te5, Ag5In5Sb60Te30, and In3SbTe2). This setup would be highly helpful for measurement of temperature-dependent resistance of wide range of materials, i.e., metals, semiconductors, and insulators illuminating information about structural change upon temperature as reflected by change in resistances, which are useful for numerous applications.

  10. Technical realisation of the VISA-II project, phase I, part IV, IZ-165-o268-1962; Tehnicka realizacija projekta VISA-II, I faza (I-V), IV deo, IZ-165-o268-1962

    Energy Technology Data Exchange (ETDEWEB)

    Pavicevic, M [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1962-12-15

    Project VISA-II is described in IX chapters as follows: introduction, definition of experiments and possibilities of performance; VISA-II channel, new experimental space in the RA reactor; hydraulic tests in the VISA-II channel; measurement of fast neutron and gamma flux in VISA-II channels; measurement of water flow through different VISA-2 irradiation capsules; fabrication of VISA-II capsules; corrosion and heavy water purity problems; safety problems of experiment VISA-2; experimental operation of VISA-II. This chapter VI includes documentation for each type of capsule, review about each experiment within the VISA-II project, the objective and purpose of the experiment as well as experimental device. [Serbo-Croat] Projekat VISA-2 opisan je u sledecih IX poglavlja: uvod, definicija eksperimenta VISA-2 i mogucnost njegovog izvodjenja; kanal VISA-2 novi eksperimentalni prostor u reaktoru RA; hidraulicna ispitivanja na tehnoloskom kanalu VISA-2; Realizacija merenja fluksa brzih neutrona i gama zracenja u kanalima VISA-2; merenje protoka vode kroz razne tipove kapsula VISA-2; Kapsule VISA-2 i njihova realizacija; problemi korozije i cistoce teske vode u projektu VISA-2; problemi sigurnosti eksperimenta VISA-2; probni pogon eksperimenta VISA-2. Ova VI glava elaborata sadrzi dokumentaciju za svaku vrstu kapsula, preglednu sliku o svakom eksperimentu u okviru projekta VISA-2, o njegovom cilju i nameni kao i o eksperimentalnom uredjaju.

  11. Local photoconductivity of microcrystalline silicon thin films measured by conductive atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Ledinsky, Martin; Fejfar, Antonin; Vetushka, Aliaksei; Stuchlik, Jiri; Rezek, Bohuslav; Kocka, Jan [Institute of Physics, Academy of Sciences of the Czech Republic, v.v.i. Cukrovarnicka 10, 162 00 Praha 6 (Czech Republic)

    2011-11-15

    Local currents measured under standard conductive atomic force microscopy (C-AFM) conditions on microcrystalline silicon ({mu}c-Si:H) thin films were studied. It was shown that the AFM detection diode illuminating the AFM cantilever (see the figure on the right side) 100 x enhanced the current flows through the photosensitive {mu}c-Si:H layer. The local current map and current-voltage characteristics were measured under dark conditions. This study enables mapping of both the dark current and photocurrent. C-AFM cantilever illuminated by the detection diode during measurement on {mu}c-Si:H thin film. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  12. Tritium in Meteorites and in Recovered Satellite Material; Tritium dans les meteorites et dans les matieres provenant d'un satellite recupere; Tritij v meteoritakh i v vozvrashchennom sputnike; Tritio en meteoritos y en el material de un satelite recuperado

    Energy Technology Data Exchange (ETDEWEB)

    Fireman, E L [Smithsonian Astrophysical Observatory, Cambridge, MA (United States)

    1962-01-15

    Tritium was measured in separated phases and in whole rock samples of the Bruderheim chondritic meteorite and in samples of lead and iron material of recovered satellites. Radioactive isotopes of argon were also measured. The tritium and argon radioactivity in the Bruderheim meteorite can be reasonably well explained by the interaction of cosmic ray particles of some thousand million volts energy with the meteoritic material. The tritium content of the recovered satellite material was more than a factor of a hundred too large to be explained by the interactions of cosmic rays or by the interactions of solar flare particles with the satellite. The high tritium content of the satellite material must result from a flux of incident tritium particles that stop in the satellite. (author) [French] Tritium dans les meteorites et dans les matieres provenant d'un satellite recupere. On a mesure la teneur en tritium d'echantillons de diverses parties et de l'ensemble de la roche formant la chondrite de Bruderheim, ainsi que celle d'echantillons de plomb et de fer preleves sur des satellites recuperes. On a egalement mesure la teneur en radioargon dans la meteorite de Bruderheim. La presence de tritium et de radioargon peut fort bien s'expliquer par l'interaction d'elements de la meteorite et de rayons cosmiques corpusculaires ayant une energie de l'ordre du milliard de volts. La teneur en tritium des satellites recuperes etait plus de cent fois trop elevee pour pouvoir etre expliquee par une interaction entre les rayons cosmiques ou les particules provenant d'eruptions solaires et le satellite etudie. La forte teneur en tritium des matieres provenant des satellites est certainement due a un flux incident de particules de tritium qui sont retenues dans le satellite. (author) [Spanish] Se midieron las concentraciones de tritio en fases separadas y en muestras enteras de roca del meteorito condritico de Bruderheim, y en muestras de plomo y de hierro de satelites recuperados

  13. Estimation of the spatial distribution of traps using space-charge-limited current measurements in an organic single crystal

    KAUST Repository

    Dacuña, Javier

    2012-09-06

    We used a mobility edge transport model and solved the drift-diffusion equation to characterize the space-charge-limited current of a rubrene single-crystal hole-only diode. The current-voltage characteristics suggest that current is injection-limited at high voltage when holes are injected from the bottom contact (reverse bias). In contrast, the low-voltage regime shows that the current is higher when holes are injected from the bottom contact as compared to hole injection from the top contact (forward bias), which does not exhibit injection-limited current in the measured voltage range. This behavior is attributed to an asymmetric distribution of trap states in the semiconductor, specifically, a distribution of traps located near the top contact. Accounting for a localized trap distribution near the contact allows us to reproduce the temperature-dependent current-voltage characteristics in forward and reverse bias simultaneously, i.e., with a single set of model parameters. We estimated that the local trap distribution contains 1.19×1011 cm -2 states and decays as exp(-x/32.3nm) away from the semiconductor-contact interface. The local trap distribution near one contact mainly affects injection from the same contact, hence breaking the symmetry in the charge transport. The model also provides information of the band mobility, energy barrier at the contacts, and bulk trap distribution with their corresponding confidence intervals. © 2012 American Physical Society.

  14. Measurement of impurity emission profiles in CHS Plasma using AXUV photodiode arrays and VUV bandpass filters

    International Nuclear Information System (INIS)

    Suzuki, C.; Peterson, B.J.; Ida, K.

    2004-01-01

    We have designed a compact and low-cost diagnostic system for spatiotemporal distributions of specific vacuum ultraviolet (VUV) emission lines from impurities in Compact Helical System (CHS) plasmas. The system consists of 20 channel absolute extreme ultraviolet photodiode arrays combined with interchangeable thin foil filters which have passbands in the VUV region. A compact mounting module which contains all the components including an in-vacuum preamplifier for immediate current-voltage conversion has been designed and successfully fabricated. A preliminary measurement with a single module using an aluminum foil filter has been carried out for monitoring the behavior of oxygen impurity in CHS, and initial results have been obtained. Two identical modules equipped with Versa Module European bus-based analog-digital converters will be available for future tomographic measurements

  15. A circuit design for front-end read-out electronics of beam homogeneity measurement

    International Nuclear Information System (INIS)

    She Qianshun; Su Hong; Xu Zhiguo; Ma Xiaoli; Hu Zhengguo; Mao Ruishi; Xu Hushan

    2011-01-01

    It introduces a circuit design of beam homogeneity measurement for heavy ion beam in the monitoring needs, which convert multichannel weak current from 10 pA to 100 nA of the output of parallel plate avalanche counter (PPAC) for large area with sensitive two-dimensional position to voltage signal from -2 V to -20 mV by current-voltage-converter (IVC) circuit which composed of T-feedback resistor networks, combined with data acquisition and processing system realized the beam homogeneity measurement in heavy ion tumor therapy of the Institute of Modern Physics. Experiments have shown that the circuit with speed and high precision. This circuit can be used for read-out of the beam for the Multiwire Proportional Chamber, Faraday Cup and other weak current sources. (authors)

  16. Measuring the lateral charge-carrier mobility in metal-insulator-semiconductor capacitors via Kelvin-probe.

    Science.gov (United States)

    Milotti, Valeria; Pietsch, Manuel; Strunk, Karl-Philipp; Melzer, Christian

    2018-01-01

    We report a Kelvin-probe method to investigate the lateral charge-transport properties of semiconductors, most notably the charge-carrier mobility. The method is based on successive charging and discharging of a pre-biased metal-insulator-semiconductor stack by an alternating voltage applied to one edge of a laterally confined semiconductor layer. The charge carriers spreading along the insulator-semiconductor interface are directly measured by a Kelvin-probe, following the time evolution of the surface potential. A model is presented, describing the device response for arbitrary applied biases allowing the extraction of the lateral charge-carrier mobility from experimentally measured surface potentials. The method is tested using the organic semiconductor poly(3-hexylthiophene), and the extracted mobilities are validated through current voltage measurements on respective field-effect transistors. Our widely applicable approach enables robust measurements of the lateral charge-carrier mobility in semiconductors with weak impact from the utilized contact materials.

  17. Measuring the lateral charge-carrier mobility in metal-insulator-semiconductor capacitors via Kelvin-probe

    Science.gov (United States)

    Milotti, Valeria; Pietsch, Manuel; Strunk, Karl-Philipp; Melzer, Christian

    2018-01-01

    We report a Kelvin-probe method to investigate the lateral charge-transport properties of semiconductors, most notably the charge-carrier mobility. The method is based on successive charging and discharging of a pre-biased metal-insulator-semiconductor stack by an alternating voltage applied to one edge of a laterally confined semiconductor layer. The charge carriers spreading along the insulator-semiconductor interface are directly measured by a Kelvin-probe, following the time evolution of the surface potential. A model is presented, describing the device response for arbitrary applied biases allowing the extraction of the lateral charge-carrier mobility from experimentally measured surface potentials. The method is tested using the organic semiconductor poly(3-hexylthiophene), and the extracted mobilities are validated through current voltage measurements on respective field-effect transistors. Our widely applicable approach enables robust measurements of the lateral charge-carrier mobility in semiconductors with weak impact from the utilized contact materials.

  18. Significantly enhanced thermal conductivity of indium arsenide nanowires via sulfur passivation.

    Science.gov (United States)

    Xiong, Yucheng; Tang, Hao; Wang, Xiaomeng; Zhao, Yang; Fu, Qiang; Yang, Juekuan; Xu, Dongyan

    2017-10-16

    In this work, we experimentally investigated the effect of sulfur passivation on thermal transport in indium arsenide (InAs) nanowires. Our measurement results show that thermal conductivity can be enhanced by a ratio up to 159% by sulfur passivation. Current-voltage (I-V) measurements were performed on both unpassivated and S-passivated InAs nanowires to understand the mechanism of thermal conductivity enhancement. We observed a remarkable improvement in electrical conductivity upon sulfur passivation and a significant contribution of electrons to thermal conductivity, which account for the enhanced thermal conductivity of the S-passivated InAs nanowires.

  19. Fosfomycin i.v. for Treatment of Severely Infected Patients

    Science.gov (United States)

    2017-07-27

    Bacterial Infections; Bone Diseases, Infectious; Osteomyelitis; Central Nervous System Bacterial Infections; Meningitis, Bacterial; Encephalitis; Brain Abscess; Urinary Tract Infections; Respiratory Tract Infections; Pneumonia, Bacterial; Skin Diseases, Bacterial; Soft Tissue Infections; Intraabdominal Infections; Sepsis; Bacteremia; Endocarditis, Bacterial

  20. Jeshtsho odin shag - i v dessjatku! / Boris Tuch

    Index Scriptorium Estoniae

    Tuch, Boris, 1946-

    2008-01-01

    Tallinna Linnateatris esitleti näitekirjaniku teist näidendiraamatut. "Näidendid II" koondab neli lavateksti : "Kaev", "Meeletu", "Latern" ja "Kaotajad". Sel puhul käis Jaan Tätte päevaks Vilsandilt ära Tallinnas. Lühidalt ka varasemate näidendite populaarsusest eri teatrite lavadel

  1. [Update of breast cancer in primary care (I/V)].

    Science.gov (United States)

    Vich, P; Brusint, B; Alvarez-Hernández, C; Cuadrado-Rouco, C; Diaz-García, N; Redondo-Margüello, E

    2014-09-01

    Breast cancer is a prevalent disease affecting all areas of the patients' lives. Therefore, family physicians should have a thorough knowledge of this disease in order to optimize the health care services for these patients, and making the best use of available resources. A series of 5 articles on breast cancer is presented below. It is based on a review of the scientific literature over the last 10 years. The first article reviews the epidemiology, risk factors, and protective factors in this disease This summary report aims to provide a current and practical review on breast cancer, providing answers to family doctors and helping them to support the patients for their benefit throughout their illness. Copyright © 2014 Sociedad Española de Médicos de Atención Primaria (SEMERGEN). Publicado por Elsevier España. All rights reserved.

  2. Razvitije turizma u nass i v drugihh stranahh / Lembo Tanning

    Index Scriptorium Estoniae

    Tanning, Lembo

    2008-01-01

    Ülevaade turismi arengust Eestis ja teistes Euroopa Liidu riikides. Diagrammid: Turismi areng 1995-2007; Eesti turismiteenuste ekspordi areng 2002-2006. Graafikud: Välis- ja siseturism Eestis 1996-2007; Eestis ööbimised 1995-2007

  3. Finskii grafitsheskii beton teper takzhe i v Estonii / Mait Eelrand

    Index Scriptorium Estoniae

    Eelrand, Mait

    2007-01-01

    Graafilise betooni meetodi arendas 1990. aastate lõpul välja soome sisearhitekt Samuli Naamanka, tehnoloogia on patenteerinud tema asutatud firma Graphic Concrete Oy. AS E-Betoonelement kasutas graafilise betooni tehnoloogiat esimesena Rakveres büroohoone fassaadi kujundamiseks. Kommenteerivad Graphic Concrete Oy tegevdirektor H. Lanningu ja K. Meus AS-st E-Betoonelement

  4. Estonskii za rubezhom i v Estonii / Roman Starapopov

    Index Scriptorium Estoniae

    Starapopov, Roman

    2007-01-01

    Tallinnas toimus rahvuskaaslaste programmi konverents, kus haridus- ja teadusminister Tõnis Lukas avaldas arvamust, et eesti keelt kõnelevate inimeste arv võiks järgmisel aastakümnel küündida kuni 1,5 miljonini

  5. Danske mejere - en fauna i vækst

    DEFF Research Database (Denmark)

    Enghoff, Henrik; Pedersen, Jan; Toft, Søren

    2014-01-01

    Since 1985 the num ber of harvestmen spe cies re corded from Den mark has grown from 17 to 25. The new spe cies and the year of their first Dan ish re cord are: Opilio canestrinii (Thorell, 1876) – 1985; Lacinius horridus (Pan zer, 1794) – 1994; Odiellus spinosus (Bosc, 1792) – 2006; Dicranopalpus...... tisciae Avram, 1968 (= L. rupestre auct.) in Den mark; and Nemastoma dentigerum Canestrini, 1873, N. bimaculatum (Fabricius, 1775), Lacinius dentiger (C.L. Koch, 1848), Leiobunum limbatum L. Koch, 1861, and Nelima doriae (Canestrini, 1871) are men tioned as can di dates for fu ture dis cov er ies...

  6. Corrosion Effects on the I-V Characteristics of Electrically ...

    African Journals Online (AJOL)

    Experimental analysis on the effects of atmospheric Pollution and environmental degradation on the electrical properties of un-protected high tension cables, using copper and Aluminum wires of various diameters as case study, has been advanced. The analysis of the various data obtained in the course of the experiment, ...

  7. Application of entropy measurement technique in grey based ...

    African Journals Online (AJOL)

    For this study, four control variables are selected current, voltage, gas flow rate and ... Keywords: Metal Inert Gas (MIG) Welding, Grey-Taguchi Method, Entropy ...... of metal inert gas welding on the corrosion and mechanical behaviour of.

  8. Using the direct current voltage gradient technology as a quality control tool during construction of new pipelines

    CSIR Research Space (South Africa)

    Masilela, Z

    1998-06-01

    Full Text Available pipelines. This technique is now increasingly gaining popularity as a good quality control tool when used on newly laid pipelines to detect coating damage, most of which could be attributed to construction work. On a recently built 50 km long gas pipeline...

  9. Direct current voltage gradient (DCVG) technique as a nondestructive testing tool for locating coating defect of buried pipelines

    International Nuclear Information System (INIS)

    Muhamad Daud; Mohd Shariff Sattar

    2009-04-01

    Protection of buried steel pipelines relies upon coating backed up by cathodic protection. All coatings are prone to general deterioration. Coating defects commonly occur as a result of construction damage, and ongoing degradation by environmental factors. Good maintenance and monitoring of protection system is important. (author)

  10. Visible photoenhanced current-voltage characteristics of Au : TiO2 nanocomposite thin films as photoanodes

    International Nuclear Information System (INIS)

    Naseri, N; Amiri, M; Moshfegh, A Z

    2010-01-01

    In this investigation, the effect of annealing temperature and concentration of gold nanoparticles on the photoelectrochemical properties of sol-gel deposited Au : TiO 2 nanocomposite thin films is studied. Various gold concentrations have been added to the TiO 2 thin films and their properties are compared. All the deposited samples are annealed at different temperatures. The optical density spectra of the films show the formation of gold nanoparticles in the films. The optical bandgap energy of the Au : TiO 2 films decreases with increasing Au concentration. The crystalline structure of the nanocomposite films is studied by x-ray diffractometry indicating the formation of gold nanocrystals in the anatase TiO 2 nanocrystalline thin films. X-ray photoelectron spectroscopy reveals that the presence of gold in the metallic state and the formation of TiO 2 are stoichiometric. The photoelectrochemical properties of the Au : TiO 2 samples are characterized using a compartment cell containing H 2 SO 4 and KOH as cathodic and anodic electrolytes, respectively. It is found that the addition of Au nanoparticles in TiO 2 films enhances the photoresponse of the layer and the addition of gold nanocrystals with an optimum value of 5 mol% resulted in the highest photoelectrochemical activity. Moreover, the photoresponse of the samples is also enhanced with an increase in the annealing temperature.

  11. Influence of semiconductor barrier tunneling on the current-voltage characteristics of tunnel metal-oxide-semiconductor diodes

    DEFF Research Database (Denmark)

    Nielsen, Otto M.

    1983-01-01

    of multistep tunneling recombination current and injected minority carrier diffusion current. This can explain the observed values of the diode quality factor n. The results also show that the voltage drop across the oxide Vox is increased with increased NA, with the result that the lowering of the minority...... carrier diode current Jmin is greater than in the usual theory. The conclusion drawn is that the increase in Vox and lowering of Jmin is due to multistep tunneling of majority carriers through the semiconductor barrier. Journal of Applied Physics is copyrighted by The American Institute of Physics.......Current–voltage characteristics have been examined for Al–SiO2–pSi diodes with an interfacial oxide thickness of delta[approximately-equal-to]20 Å. The diodes were fabricated on and oriented substrates with an impurity concentration in the range of NA=1014–1016 cm−3. The results show that for low...

  12. Adsorption behavior and current-voltage characteristics of CdSe nanocrystals on hydrogen-passivated silicon

    DEFF Research Database (Denmark)

    Walzer, Karsten; Quaade, Ulrich; Ginger, D.S.

    2002-01-01

    Using scanning tunneling microscopy and spectroscopy we have studied both the geometric distribution and the conduction properties of organic shell capped CdSe nanocrystals adsorbed on hydrogen-passivated Si(100). At submonolayer concentrations, the nanocrystal distribution on the surface was found...... found that the current through the MIS junction is limited by the nanocrystals only in one bias direction, while in the other bias direction the current is limited by the semiconducting substrate. This property may be of relevance for the construction of hybrid electronic devices combining semiconductor...

  13. Simulation of current-voltage characteristics of a MOS structure considering the tunnel transport of carriers in semiconductor

    International Nuclear Information System (INIS)

    Vexler, M I

    2006-01-01

    The effect of a tunnel charge transport in the near-surface region of silicon on the electrical characteristics of MOS structures with a 2-3 nm insulator layer is studied theoretically. An equilibrium condition for the substrate is assumed. The cases of an Al and polySi gate are considered. The possibility of a 'double' (in Si and through SiO 2 ) tunnelling expands the energy range of transported particles, which increases one of the components of the total tunnel current. The proposed model allows for the improved simulation of gate current in MOSFETs, which is especially important for highly-doped substrates

  14. Effect of the periphery of metal-semiconductor contacts with Schottky barriers on their static current-voltage characteristic

    International Nuclear Information System (INIS)

    Torkhov, N. A.

    2010-01-01

    Kelvin probe atomic-force microscopy of the electrostatic surface potential of gold Schottky contacts on n-GaAs showed that there is an extended transition area (halo) (tens of micrometers) around contacts in which the surface potential varies from the n-GaAs free surface potential to the gold contact surface potential. The contact potential and its distribution in the surrounding halo are controlled by the contact structure. The study of spreading currents showed that there is a high-conductance area (periphery) around the contact perimeter due to strong electric fields of the halo, which causes leakage currents. The conductivity of the main contact area is caused by 100- to 200-nm local areas with higher and lower conducting abilities. Mesa formation around contacts causes a decrease in the work function, a decrease in the halo extent and electric field strength, which is accompanied by spreading and decreasing of the peripheral area conductance. This results in disappearance of leakage currents and a decrease in the ideality index. In contrast, protection of the peripheral area by a SiO 2 insulating film 0.5 μm thick increases the work function, which is accompanied by the formation of potential lobes around the contact in two mutually perpendicular crystallographic directions. A stronger penetration of halo electric fields into the contact area results in an increase in the ideality index and disappearance of high-conductance peripheral area and leakage currents. The difference between the electrical properties of the periphery, gold grains, and their boundaries controls the contact switching mechanism when applying forward or reverse biases.

  15. Li-Po Battery Charger Based on the Constant Current/Voltage Parallel Resonant Converter Operating in ZVS

    Directory of Open Access Journals (Sweden)

    Alberto M. Pernía

    2018-04-01

    Full Text Available Battery requirements for electrical vehicles are continuously becoming more demanding in terms of energy density and reliability. Nowadays, batteries for drones must be able to supply 100 A for 15 min, not to mention the specifications required for batteries in electrical vehicles. These specifications result in more stringent specifications for battery chargers. They are required to be more efficient, flexible, and, as with any another power equipment, to have reduced size and weight. Since the parallel resonant converter can operate as a current source and as a voltage source, this paper presents a battery charger power stage for lithium ion polymer batteries, based on the above topology, operating in zero voltage switching mode, and implementing frequency and duty cycle control.

  16. Theoretical investigation on current-voltage characteristics in all-carbon molecular device with different contact geometries

    International Nuclear Information System (INIS)

    Ye Fuqiu; Fan Zhiqiang; He Jun; Peng Jun; Tang Liming

    2012-01-01

    Applying nonequilibrium Green's functions in combination with the first-principles density-functional theory, we investigate electronic transport properties of an all-carbon molecular device consisting of one phenalenyl molecule and two zigzag graphene nanoribbons. The results show that the electronic transport properties are strongly dependent on the contact geometry and device's currents can drop obviously when the connect sites change from second-nearest sites from the central atom of the molecule (S site) to third-nearest sites from the central atom of the molecule (T site). More importantly, the negative differential resistance behavior is only observed on the negative bias region when the molecule connects the graphene nanoribbons through two T sites.

  17. Dark Current And Voltage Measurements Of Metal-Organic-Semiconductor (M-Or-S) Diode

    International Nuclear Information System (INIS)

    Adianto

    1996-01-01

    . Some Metal-Organic-Semiconductor (M-Or-S) thin film diodes, constructed with an organic polymer (polymerized toluene) as an active component has been successfully fabricated. The thin film M-Or-S diodes were fabricated on an n-type silicon with resistivity of 250-500 Ocm and p type silicon with resistivity of 10-20 Ocm as a substrate with polymerized toluene used as insulator. When deposited on silicon wafers with electrode of evaporated Ni on the n-type silicon and evaporated Au as the electrode on the polymerized toluene film, the electronic devices of Metal-Organic- Semiconductor (M-Or-S) type can be produced with one of its characteristics is that their light sensitivity. A plasma ion deposition system was constructed and used to deposit organic monomeric substance (toluene) that functioned as an isolator between semiconductor and the evaporated metal electrodes. The current-voltage measurements for different configurations of M-Or-S devices were carried out to determine the current-voltage (1-V) characteristics for M-Or-S devices with different materials and thicknesses. In addition to the 1-V measurement mentioned before, 1-V measurements of the devices were also carried out by using a curve tracer oscilloscope, and the picture of the effective parameters of each of the device could be taken by using a polaroid camera. Since the devices are very sensitive to light, the devices were all tested in a black-box which was covered by a black cloth to make sure that there was no light coming through. The experimental results for p- and n-type silicon substrates showed that an M-Or-S diode with n-type gave a higher breakdown voltage than that p- type silicon. In addition, the reverse bias breakdown voltage increased as the thickness of the thin film increased in the range of 50 -2500 V/μm

  18. Electron cyclotron emission measurements at the stellarator TJ-K

    Energy Technology Data Exchange (ETDEWEB)

    Sichardt, Gabriel; Ramisch, Mirko [Institut fuer Grenzflaechenverfahrenstechnik und Plasmatechnologie, Universitaet Stuttgart (Germany); Koehn, Alf [Max-Planck-Institut fuer Plasmaphysik, Garching (Germany)

    2016-07-01

    Electron temperature (T{sub e}) measurements in the magnetised plasmas of the stellarator TJ-K are currently performed by means of Langmuir probes. The use of these probes is restricted to relatively low temperatures and the measurement of temperature profiles requires the acquisition of the local current-voltage characteristics which limits strongly the sampling rate. As an alternative, T{sub e} can be measured using the electron cyclotron emission (ECE) that is generated by the gyration of electrons in magnetised plasmas. Magnetic field gradients in the plasma lead to a spatial distribution of emission frequencies and thus the measured intensity at a given frequency can be related to its point of origin. The T{sub e} dependence of the intensity then leads to a temperature profile along the line of sight for Maxwellian velocity distributions. A diagnostic system for T{sub e} measurements using ECE is currently being set up at TJ-K. When non-thermal electrons are present the emission spectrum changes dramatically. Therefore, the ECE can also be used to investigate the contribution of fast electrons to previously observed toroidal net currents in TJ-K. Simulations are used to examine the role of electron drift orbits in generating these currents.

  19. Methods for the numerical calculation of the plasma potential from measured Langmuir probe characteristics

    International Nuclear Information System (INIS)

    Seifert, W.; Johanning, D.; Bankov, N.

    1986-01-01

    In a previous paper the results of the Langmuir probe experiment carried out on board of two INTERKOSMOS satellites have been described. The experiences have shown that the usage of high quality algorithms for analyzing the current-voltage-characteristics is necessary to yield real physical parameters. The key problem is the determination of the plasma potential. This paper reviews the different methods to determine the plasma potential especially under the circumstances of computer application. The test of the well developed methods shows, that for the evaluation of the applied methods a number of different factors, discussed in the following sections of this paper, has to be taken into account. The used test data are model values or real measurements obtained by the satellite missions IK-10, IK-18 and BULGARIA-1300. The computer procedures have been realized as FORTRAN-subroutines for the BESM 6 and ES 1040. (author)

  20. Superconductor (Nb)-charge density wave (NbSe sub 3) point-contact spectroscopy

    CERN Document Server

    Sinchenko, A A

    2003-01-01

    Measurements of differential current-voltage (I-V) characteristics of point contacts between Nb and the charge density wave (CDW) conductor NbSe sub 3 formed along the conducting chain direction are reported. Below the superconducting transition of Nb, we have clearly observed Andreev reflection of the gapless electrons of NbSe sub 3. Analysis of the spectra obtained indicates that when the energy of injected particles exceeds the superconducting energy gap, the superconductivity near the S-CDW interface is suppressed because of non-equilibrium effects.

  1. Tapping of electrical energy from plant leaves: Sansevieria trifasciata

    Energy Technology Data Exchange (ETDEWEB)

    Jain, K.A.; Hundet, A.; Abraham, S.; Nigam, H.L.

    Some investigations on the prospective use of plant leaves as useful battery material have been described in this paper. A bio-emf-device (BED) has been developed using the leaf of Sansevieria trifasciata. The current - voltage (I-V) and the current - power (I-power) characteristics have been measured. Kinetic studies have also been made taking different loads. The results based on these characteristics of BED indicate a close involvement of the bio-contribution in the generation of electric power. Some applications of using these BEDs are also suggested to operate low power electronic circuits.

  2. Physical Mechanisms Responsible for Electrical Conduction in Pt/GaN Schottky Diodes

    Directory of Open Access Journals (Sweden)

    H. MAZARI

    2014-05-01

    Full Text Available The current-voltage (I-V characteristics of Pt/(n.u.d-GaN and Pt/Si-doped-GaN diodes Schottky are investigated. Based on these measurements, physical mechanisms responsible for electrical conduction have been suggested. The contribution of thermionic-emission current and various other current transport mechanisms were assumed when evaluating the Schottky barrier height. Thus the generation-recombination, tunneling and leakage currents caused by inhomogeneities and defects at metal-semiconductor interface were taken into account.

  3. Effect of thermal implying during ageing process of nanorods growth on the properties of zinc oxide nanorod arrays

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, A. S., E-mail: kyrin-samaxi@yahoo.com; Mamat, M. H., E-mail: mhmamat@salam.uitm.edu.my; Rusop, M., E-mail: rusop@salam.uitm.my [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia); NANO-SciTech Centre (NST), Institute of Science (IOS), Universiti Teknologi MARA - UiTM, 40450 Shah Alam, Selangor (Malaysia); Malek, M. F., E-mail: firz-solarzelle@yahoo.com; Abdullah, M. A. R., E-mail: ameerridhwan89@gmail.com; Sin, M. D., E-mail: diyana0366@johor.uitm.edu.my [NANO-ElecTronic Centre (NET), Faculty of Electrical Engineering, Universiti Teknologi MARA (UiTM), 40450 Shah Alam, Selangor (Malaysia)

    2016-07-06

    Undoped and Sn-doped Zinc oxide (ZnO) nanostructures have been fabricated using a simple sol-gel immersion method at 95°C of growth temperature. Thermal sourced by hot plate stirrer was supplied to the solution during ageing process of nanorods growth. The results showed significant decrement in the quality of layer produced after the immersion process where the conductivity and porosity of the samples reduced significantly due to the thermal appliance. The structural properties of the samples have been characterized using field emission scanning electron microscopy (FESEM) electrical properties has been characterized using current voltage (I-V) measurement.

  4. Observation of unusual irreversible/reversible effects in a macroscopic cylindrical hole drilled in superconducting Bi-Sr-Ca-Cu-O

    International Nuclear Information System (INIS)

    Yetis, H.; Kilic, A.; Kilic, K.; Altinkok, A.; Olutas, M.

    2008-01-01

    Current-voltage (I-V) measurements were carried out for different current sweep rates (dI/dt) of transport current at zero magnetic field (H = 0) and H ≠ 0 in a polycrystalline sample of Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O x (BSCCO) with a macroscopic cylindrical hole (CH) drilled. Similar measurements were also performed in the same BSCCO sample without CH for a comparison before drilling CH. For the same values of H, T, and dI/dt taken for both samples, it was observed that hysteresis effects appear in I-V curves upon cycling of transport current in upward and downward directions which contain the increasing and decreasing current values, respectively. However these effects which are seen in I-V curves of BSCCO sample with CH is more prominent than that of the BSCCO sample without CH. Further, the irreversibility effects in I-V curves of the BSCCO sample without CH disappears for H ≠ 0 exhibiting nearly a linear behaviour, whereas the hysteretic behaviour in I-V curves of the BSCCO sample with CH is still observed. This interesting behaviour could be evaluated that macroscopic cylindrical hole improves pinning properties of sample acting as a macroscopic flux pinning center for flux lines

  5. Observation of unusual irreversible/reversible effects in a macroscopic cylindrical hole drilled in superconducting Bi-Sr-Ca-Cu-O

    Energy Technology Data Exchange (ETDEWEB)

    Yetis, H. [Department of Physics, Turgut Gulez Research Laboratory, Abant Izzet Baysal University, 14280 Bolu (Turkey)], E-mail: yetis_h@ibu.edu.tr; Kilic, A.; Kilic, K.; Altinkok, A.; Olutas, M. [Department of Physics, Turgut Gulez Research Laboratory, Abant Izzet Baysal University, 14280 Bolu (Turkey)

    2008-09-15

    Current-voltage (I-V) measurements were carried out for different current sweep rates (dI/dt) of transport current at zero magnetic field (H = 0) and H {ne} 0 in a polycrystalline sample of Bi{sub 1.7}Pb{sub 0.3}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} (BSCCO) with a macroscopic cylindrical hole (CH) drilled. Similar measurements were also performed in the same BSCCO sample without CH for a comparison before drilling CH. For the same values of H, T, and dI/dt taken for both samples, it was observed that hysteresis effects appear in I-V curves upon cycling of transport current in upward and downward directions which contain the increasing and decreasing current values, respectively. However these effects which are seen in I-V curves of BSCCO sample with CH is more prominent than that of the BSCCO sample without CH. Further, the irreversibility effects in I-V curves of the BSCCO sample without CH disappears for H {ne} 0 exhibiting nearly a linear behaviour, whereas the hysteretic behaviour in I-V curves of the BSCCO sample with CH is still observed. This interesting behaviour could be evaluated that macroscopic cylindrical hole improves pinning properties of sample acting as a macroscopic flux pinning center for flux lines.

  6. Grain boundary layer behavior in ZnO/Si heterostructure

    International Nuclear Information System (INIS)

    Liu Bingce; Liu Cihui; Yi Bo

    2010-01-01

    The grain boundary layer behavior in ZnO/Si heterostucture is investigated. The current-voltage (I-V) curves, deep level transient spectra (DLTS) and capacitance-voltage (C-V) curves are measured. The transport currents of ZnO/Si heterojunction are dominated by grain boundary layer as high densities of interfacial states existed. The interesting phenomenon that the crossing of In I-V curves of ZnO/Si heterojunction at various measurement temperatures and the decrease of its effective barrier height with the decrement of temperature are in contradiction with the ideal heterojunction thermal emission model is observed. The details will be discussed in the following. (semiconductor physics)

  7. Imaging of current density distributions with a Nb weak-link scanning nano-SQUID microscope

    Science.gov (United States)

    Shibata, Yusuke; Nomura, Shintaro; Kashiwaya, Hiromi; Kashiwaya, Satoshi; Ishiguro, Ryosuke; Takayanagi, Hideaki

    2015-10-01

    Superconducting quantum interference devices (SQUIDs) are accepted as one of the highest magnetic field sensitive probes. There are increasing demands to image local magnetic fields to explore spin properties and current density distributions in a two-dimensional layer of semiconductors or superconductors. Nano-SQUIDs have recently attracting much interest for high spatial resolution measurements in nanometer-scale samples. Whereas weak-link Dayem Josephson junction nano-SQUIDs are suitable to miniaturization, hysteresis in current-voltage (I-V) characteristics that is often observed in Dayem Josephson junction is not desirable for a scanning microscope. Here we report on our development of a weak-link nano-SQUIDs scanning microscope with small hysteresis in I-V curve and on reconstructions of two-dimensional current density vector in two-dimensional electron gas from measured magnetic field.

  8. Effects of ageing on the electrical characteristics of Zn/ZnS/n-GaAs/In structure

    Science.gov (United States)

    Güzeldir, B.; Sağlam, M.

    2016-04-01

    Zn/ZnS/n-GaAs/In structure has been fabricated by the Successive Ionic Layer Adsorption and Reaction (SILAR) method and the influence of the time dependent or ageing on the characteristic parameters are examined. The current-voltage (I-V) of the structure have been measured immediately, 1, 3, 5, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150 and 165 days after fabrication of this structure. The characteristics parameters of this structure such as barrier height, ideality factor, series resistance are calculated from the I-V measurements. It has been seen that the changes of characteristic parameters such as barrier height, ideality factor and series resistance of Zn/ZnS/n-GaAs/In structure have lightly changed with increasing ageing time.

  9. Charge transport in highly efficient iridium cored electrophosphorescent dendrimers

    Science.gov (United States)

    Markham, Jonathan P. J.; Samuel, Ifor D. W.; Lo, Shih-Chun; Burn, Paul L.; Weiter, Martin; Bässler, Heinz

    2004-01-01

    Electrophosphorescent dendrimers are promising materials for highly efficient light-emitting diodes. They consist of a phosphorescent core onto which dendritic groups are attached. Here, we present an investigation into the optical and electronic properties of highly efficient phosphorescent dendrimers. The effect of dendrimer structure on charge transport and optical properties is studied using temperature-dependent charge-generation-layer time-of-flight measurements and current voltage (I-V) analysis. A model is used to explain trends seen in the I-V characteristics. We demonstrate that fine tuning the mobility by chemical structure is possible in these dendrimers and show that this can lead to highly efficient bilayer dendrimer light-emitting diodes with neat emissive layers. Power efficiencies of 20 lm/W were measured for devices containing a second-generation (G2) Ir(ppy)3 dendrimer with a 1,3,5-tris(2-N-phenylbenzimidazolyl)benzene electron transport layer.

  10. Performance Characterization of Dye-Sensitized Photovoltaics under Indoor Lighting.

    Science.gov (United States)

    Chen, Chia-Yuan; Jian, Zih-Hong; Huang, Shih-Han; Lee, Kun-Mu; Kao, Ming-Hsuan; Shen, Chang-Hong; Shieh, Jia-Min; Wang, Chin-Li; Chang, Chiung-Wen; Lin, Bo-Zhi; Lin, Ching-Yao; Chang, Ting-Kuang; Chi, Yun; Chi, Cheng-Yu; Wang, Wei-Ting; Tai, Yian; Lu, Ming-De; Tung, Yung-Liang; Chou, Po-Ting; Wu, Wen-Ti; Chow, Tahsin J; Chen, Peter; Luo, Xiang-Hao; Lee, Yuh-Lang; Wu, Chih-Chung; Chen, Chih-Ming; Yeh, Chen-Yu; Fan, Miao-Syuan; Peng, Jia-De; Ho, Kuo-Chuan; Liu, Yu-Nan; Lee, Hsiao-Yi; Chen, Chien-Yu; Lin, Hao-Wu; Yen, Chia-Te; Huang, Yu-Ching; Tsao, Cheng-Si; Ting, Yu-Chien; Wei, Tzu-Chien; Wu, Chun-Guey

    2017-04-20

    Indoor utilization of emerging photovoltaics is promising; however, efficiency characterization under room lighting is challenging. We report the first round-robin interlaboratory study of performance measurement for dye-sensitized photovoltaics (cells and mini-modules) and one silicon solar cell under a fluorescent dim light. Among 15 research groups, the relative deviation in power conversion efficiency (PCE) of the samples reaches an unprecedented 152%. On the basis of the comprehensive results, the gap between photometry and radiometry measurements and the response of devices to the dim illumination are identified as critical obstacles to the correct PCE. Therefore, we use an illuminometer as a prime standard with a spectroradiometer to quantify the intensity of indoor lighting and adopt the reverse-biased current-voltage (I-V) characteristics as an indicator to qualify the I-V sampling time for dye-sensitized photovoltaics. The recommendations can brighten the prospects of emerging photovoltaics for indoor applications.

  11. Use of ultrasound measurement of the inferior vena cava diameter as an objective tool in the assessment of children with clinical dehydration.

    Science.gov (United States)

    Chen, Lei; Kim, Yunie; Santucci, Karen A

    2007-10-01

    Bedside ultrasonography (US) measurement of the inferior vena cava (IVC) and aorta (Ao) may be useful in objectively assessing children with dehydration. The objectives of this study were 1) to compare the IVC and Ao diameters (IVC/Ao) ratio of dehydrated children with controls and 2) to compare the IVC/Ao ratio before and after intravenous (i.v.) rehydration in children with dehydration. This prospective observational study was performed in an urban pediatric emergency department. Children between 6 months and 16 years of age with clinical evidence of dehydration were enrolled. Bedside US measurements of the IVC and Ao were taken before and immediately after i.v. fluids were administered. An age-, gender-, and weight-matched control without dehydration was enrolled for each subject. The IVC/Ao ratios of subjects and controls were compared using Wilcoxon signed rank test, as were the ratios before and after i.v. hydration for each subject. Thirty-six pairs of subjects and matched controls were enrolled. The IVC/Ao ratios in the subjects were lower as compared with controls (mean of 0.75 vs. 1.01), with a mean difference of 0.26 (95% confidence interval = 0.18 to 0.35). In subjects, the IVC/Ao ratios were significantly lower before i.v. hydration (mean of 0.75 vs. 1.09), with a mean difference of 0.34 (95% confidence interval = 0.29 to 0.39). As measured by bedside US measurement, the IVC/Ao ratio is lower in children clinically assessed to be dehydrated. Furthermore, it increases with administration of i.v. fluid boluses.

  12. What quantum measurements measure

    Science.gov (United States)

    Griffiths, Robert B.

    2017-09-01

    A solution to the second measurement problem, determining what prior microscopic properties can be inferred from measurement outcomes ("pointer positions"), is worked out for projective and generalized (POVM) measurements, using consistent histories. The result supports the idea that equipment properly designed and calibrated reveals the properties it was designed to measure. Applications include Einstein's hemisphere and Wheeler's delayed choice paradoxes, and a method for analyzing weak measurements without recourse to weak values. Quantum measurements are noncontextual in the original sense employed by Bell and Mermin: if [A ,B ]=[A ,C ]=0 ,[B ,C ]≠0 , the outcome of an A measurement does not depend on whether it is measured with B or with C . An application to Bohm's model of the Einstein-Podolsky-Rosen situation suggests that a faulty understanding of quantum measurements is at the root of this paradox.

  13. Effects of a highly Si-doped GaN current spreading layer at the n+-GaN/multi-quantum-well interface on InGaN/GaN blue-light-emitting diodes

    International Nuclear Information System (INIS)

    Kim, C. S.; Cho, H. K.; Choi, R. J.; Hahn, Y. B.; Lee, H. J.; Hong, C. H.

    2004-01-01

    Highly Si-doped GaN thin current spreading layer (CSL) with various carrier concentrations were inserted before the n + -GaN/multi-quantum-well (MQW) interface controlled by the growth rate and the modulated Si-doping in InGaN/GaN blue light-emitting diodes (LEDs), and their effects were investigated by using capacitance-voltage (C-V), current-voltage (I-V), and output power measurements. The LEDs with a highly Si-doped CSL show enhanced I-V characteristics and increased output power with increasing carrier concentration up to some critical point in the CSL. This means that proper high Si-doping in some limited area before the interface may enhance the device performance through the current spreading effect.

  14. Electric properties and fabrication of IMI-O LB films containing the imidazole group

    CERN Document Server

    Yoo, S Y; Kwon, Y S; Park, J C

    1999-01-01

    We fabricated an IMI-O polymer containing an imidazole group that could form a complex structure between the monolayer and the metal ions at the air-water interface. Also, the monolayer behavior at the air-water interface and the electrical properties of metal-complexed Langmuir-Blodgett (LB) films were investigated by using Brewster angle microscopy (BAM) and current-voltage(I-V) measurements. The difference in the BAM images between the pure water and the aqueous metal ions is attributed to the interactions of the copolymers with the metal ions at the interface and the consequent change of the monolayer organization. In the I-V characteristics, the current for LB films with different metal ion depended on the quantity of the metal-ion complexed with the LB film due to the interaction between the metal ion and the IMI-O polymer.

  15. Electrical bistabilities and memory stabilities of nonvolatile bistable devices fabricated utilizing C60 molecules embedded in a polymethyl methacrylate layer

    International Nuclear Information System (INIS)

    Cho, Sung Hwan; Lee, Dong Ik; Jung, Jae Hun; Kim, Tae Whan

    2009-01-01

    Current-voltage (I-V) measurements on Al/fullerene (C 60 ) molecules embedded in polymethyl methacrylate/Al devices at 300 K showed a current bistability due to the existence of the C 60 molecules. The on/off ratio of the current bistability for the memory devices was as large as 10 3 . The retention time of the devices was above 2.5 x 10 4 s at room temperature, and cycling endurance tests on these devices indicated that the ON and OFF currents showed no degradation until 50 000 cycles. Carrier transport mechanisms for the nonvolatile bistable devices are described on the basis of the I-V experimental and fitting results.

  16. Carrier transport in flexible organic bistable devices of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) polymer layer

    International Nuclear Information System (INIS)

    Son, Dong-Ick; Park, Dong-Hee; Choi, Won Kook; Cho, Sung-Hwan; Kim, Won-Tae; Kim, Tae Whan

    2009-01-01

    The bistable effects of ZnO nanoparticles embedded in an insulating poly(methyl methacrylate) (PMMA) polymer single layer by using flexible polyethylene terephthalate (PET) substrates were investigated. Transmission electron microscopy (TEM) images revealed that ZnO nanoparticles were formed inside the PMMA polymer layer. Current-voltage (I-V) measurement on the Al/ZnO nanoparticles embedded in an insulating PMMA polymer layer/ITO/PET structures at 300 K showed a nonvolatile electrical bistability behavior with a flat-band voltage shift due to the existence of the ZnO nanoparticles, indicative of trapping, storing, and emission of charges in the electronic states of the ZnO nanoparticles. The carrier transport mechanism of the bistable behavior for the fabricated organic bistable device (OBD) structures is described on the basis of the I-V results by analyzing the effect of space charge.

  17. Film thickness degradation of Au/GaN Schottky contact characteristics

    International Nuclear Information System (INIS)

    Wang, K.; Wang, R.X.; Fung, S.; Beling, C.D.; Chen, X.D.; Huang, Y.; Li, S.; Xu, S.J.; Gong, M.

    2005-01-01

    Electrical characteristics of Au/n-GaN Schottky contacts with different Au film thicknesses up to 1300 A, have been investigated using current-voltage (I-V) and capacitance-voltage (C-V) techniques. Results show a steady decrease in the quality of the Schottky diodes for increasing Au film thickness. I-V measurements indicate that thin ( 500 A). Depth profiling Auger electron spectroscopy (AES) shows that the width of the Au/GaN junction interface increases with increasing Au thickness, suggesting considerable inter-mixing of Au, Ga and N. The results have been interpreted in terms of Ga out-diffusion from the GaN giving rise to gallium vacancies that in turn act as sites for electron-hole pair generation within the depletion region. The study supports the recent suggestion that gallium vacancies associated with threaded dislocations are playing an important role in junction breakdown

  18. DNA-FET using carbon nanotube electrodes

    International Nuclear Information System (INIS)

    Sasaki, T K; Ikegami, A; Aoki, N; Ochiai, Y

    2006-01-01

    We demonstrate DNA field effect transistor (DNA-FET) using multiwalled carbon nanotube (MWNT) as nano-structural source and drain electrodes. The MWNT electrodes have been fabricated by focused ion-beam bombardment (FIBB). A very short channel, approximately 50 nm, was easily formed between the severed MWNT. The current-voltage (I-V) characteristics of DNA molecules between the MWNT electrodes showed hopping transport property. We have also measured the gate-voltage dependence in the I-V characteristics and found that poly DNA molecules exhibits p-type conduction. The transport of DNA-FET can be explained by two hopping lengths which depend on the range of the source-drain bias voltages

  19. Vortex dynamics in superconducting transition edge sensors

    Science.gov (United States)

    Ezaki, S.; Maehata, K.; Iyomoto, N.; Asano, T.; Shinozaki, B.

    2018-02-01

    The temperature dependence of the electrical resistance (R-T) and the current-voltage (I-V) characteristics has been measured and analyzed in a 40 nm thick Ti thin film, which is used as a transition edge sensor (TES). The analyses of the I-V characteristics with the vortex-antivortex pair dissociation model indicate the possible existence of the Berezinskii-Kosterlitz-Thouless (BKT) transition in two-dimensional superconducting Ti thin films. We investigated the noise due to the vortices' flow in TESs. The values of the current noise spectral density in the TESs were estimated by employing the vortex dynamics caused by the BKT transition in the Ti thin films. The estimated values of the current noise spectral density induced by the vortices' flow were in respectable agreement with the values of excess noise experimentally observed in the TESs with Ti/Au bilayer.

  20. Measurement of resistance switching dynamics in copper sulfide memristor structures

    Science.gov (United States)

    McCreery, Kaitlin; Olson, Matthew; Teitsworth, Stephen

    Resistance switching materials are the subject of current research in large part for their potential to enable novel computing devices and architectures such as resistance random access memories and neuromorphic chips. A common feature of memristive structures is the hysteretic switching between high and low resistance states which is induced by the application of a sufficiently large electric field. Here, we describe a relatively simple wet chemistry process to fabricate Cu2 S / Cu memristive structures with Cu2 S film thickness ranging up to 150 micron. In this case, resistance switching is believed to be mediated by electromigration of Cu ions from the Cu substrate into the Cu2 S film. Hysteretic current-voltage curves are measured and reveal switching voltages of about 0.8 Volts with a relatively large variance and independent of film thickness. In order to gain insight into the dynamics and variability of the switching process, we have measured the time-dependent current response to voltage pulses of varying height and duration with a time resolution of 1 ns. The transient response consists of a deterministic RC component as well as stochastically varying abrupt current steps that occur within a few microseconds of the pulse application.

  1. Accurate surface potential determination in Schottky diodes by the use of a correlated current and capacitance voltage measurements. Application to n-InP

    International Nuclear Information System (INIS)

    Ahaitouf, Ali; Ahaitouf, Abdelaziz; Salvestrini, Jean Paul; Srour, Hussein

    2011-01-01

    Based on current voltage (I—V g ) and capacitance voltage (C—V g ) measurements, a reliable procedure is proposed to determine the effective surface potential V d (V g ) in Schottky diodes. In the framework of thermionic emission, our analysis includes both the effect of the series resistance and the ideality factor, even voltage dependent. This technique is applied to n-type indium phosphide (n-InP) Schottky diodes with and without an interfacial layer and allows us to provide an interpretation of the observed peak on the C—V g measurements. The study clearly shows that the depletion width and the flat band barrier height deduced from C—V g , which are important parameters directly related to the surface potential in the semiconductor, should be estimated within our approach to obtain more reliable information. (semiconductor devices)

  2. Quantifying and Reducing Curve-Fitting Uncertainty in Isc

    Energy Technology Data Exchange (ETDEWEB)

    Campanelli, Mark; Duck, Benjamin; Emery, Keith

    2015-06-14

    Current-voltage (I-V) curve measurements of photovoltaic (PV) devices are used to determine performance parameters and to establish traceable calibration chains. Measurement standards specify localized curve fitting methods, e.g., straight-line interpolation/extrapolation of the I-V curve points near short-circuit current, Isc. By considering such fits as statistical linear regressions, uncertainties in the performance parameters are readily quantified. However, the legitimacy of such a computed uncertainty requires that the model be a valid (local) representation of the I-V curve and that the noise be sufficiently well characterized. Using more data points often has the advantage of lowering the uncertainty. However, more data points can make the uncertainty in the fit arbitrarily small, and this fit uncertainty misses the dominant residual uncertainty due to so-called model discrepancy. Using objective Bayesian linear regression for straight-line fits for Isc, we investigate an evidence-based method to automatically choose data windows of I-V points with reduced model discrepancy. We also investigate noise effects. Uncertainties, aligned with the Guide to the Expression of Uncertainty in Measurement (GUM), are quantified throughout.

  3. Quantifying and Reducing Curve-Fitting Uncertainty in Isc: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Campanelli, Mark; Duck, Benjamin; Emery, Keith

    2015-09-28

    Current-voltage (I-V) curve measurements of photovoltaic (PV) devices are used to determine performance parameters and to establish traceable calibration chains. Measurement standards specify localized curve fitting methods, e.g., straight-line interpolation/extrapolation of the I-V curve points near short-circuit current, Isc. By considering such fits as statistical linear regressions, uncertainties in the performance parameters are readily quantified. However, the legitimacy of such a computed uncertainty requires that the model be a valid (local) representation of the I-V curve and that the noise be sufficiently well characterized. Using more data points often has the advantage of lowering the uncertainty. However, more data points can make the uncertainty in the fit arbitrarily small, and this fit uncertainty misses the dominant residual uncertainty due to so-called model discrepancy. Using objective Bayesian linear regression for straight-line fits for Isc, we investigate an evidence-based method to automatically choose data windows of I-V points with reduced model discrepancy. We also investigate noise effects. Uncertainties, aligned with the Guide to the Expression of Uncertainty in Measurement (GUM), are quantified throughout.

  4. Spin-Dependent Processes Measured without a Permanent Magnet.

    Science.gov (United States)

    Fontanesi, Claudio; Capua, Eyal; Paltiel, Yossi; Waldeck, David H; Naaman, Ron

    2018-05-07

    A novel Hall circuit design that can be incorporated into a working electrode, which is used to probe spin-selective charge transfer and charge displacement processes, is reviewed herein. The general design of a Hall circuit based on a semiconductor heterostructure, which forms a shallow 2D electron gas and is used as an electrode, is described. Three different types of spin-selective processes have been studied with this device in the past: i) photoinduced charge exchange between quantum dots and the working electrode through chiral molecules is associated with spin polarization that creates a local magnetization and generates a Hall voltage; ii) charge polarization of chiral molecules by an applied voltage is accompanied by a spin polarization that generates a Hall voltage; and iii) cyclic voltammetry (current-voltage) measurements of electrochemical redox reactions that can be spin-analyzed by the Hall circuit to provide a third dimension (spin) in addition to the well-known current and voltage dimensions. The three studies reviewed open new doors into understanding both the spin current and the charge current in electronic materials and electrochemical processes. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Schottky barrier parameters and low frequency noise characteristics of graphene-germanium Schottky barrier diode

    Science.gov (United States)

    Khurelbaatar, Zagarzusem; Kil, Yeon-Ho; Shim, Kyu-Hwan; Cho, Hyunjin; Kim, Myung-Jong; Lee, Sung-Nam; Jeong, Jae-chan; Hong, Hyobong; Choi, Chel-Jong

    2016-03-01

    We investigated the electrical properties of chemical vapor deposition-grown monolayer graphene/n-type germanium (Ge) Schottky barrier diodes (SBD) using current-voltage (I-V) characteristics and low frequency noise measurements. The Schottky barrier parameters of graphene/n-type Ge SBDs, such as Schottky barrier height (VB), ideality factor (n), and series resistance (Rs), were extracted using the forward I-V and Cheung's methods. The VB and n extracted from the forward ln(I)-V plot were found to be 0.63 eV and 1.78, respectively. In contrast, from Cheung method, the VB and n were calculated to be 0.53 eV and 1.76, respectively. Such a discrepancy between the values of VB calculated from the forward I-V and Cheung's methods indicated a deviation from the ideal thermionic emission of graphene/n-type Ge SBD associated with the voltage drop across graphene. The low frequency noise measurements performed at the frequencies in the range of 10 Hz-1 kHz showed that the graphene/n-type Ge SBD had 1/f γ frequency dependence, with γ ranging from 1.09 to 1.12, regardless of applied forward biases. Similar to forward-biased SBDs operating in the thermionic emission mode, the current noise power spectral density of graphene/n-type Ge SBD was linearly proportional to the forward current.

  6. Natural stream flow-rates measurements by tracer techniques

    International Nuclear Information System (INIS)

    Cuellar Mansilla, J.

    1982-01-01

    This paper presents the study of the precision obtained measuring the natural stream flow rates by tracer techniques, especially when the system presents a great slope and a bed constituted by large and extended particle size. The experiences were realized in laboratory pilot channels with flow-rates between 15 and 130 [1/s]; and in natural streams with flow-rates from 1 to 25 m 3 /s. Tracer used were In-133m and Br-82 for laboratory and field measurements respectively. In both cases the tracer was injected as a pulse and its dilution measured collecting samples in the measured section, at constant flow-rates, of 5[1] in laboratory experiences and 60[1] of water in field experiences. Precisions obtained at a 95% confidence level were about 2% for laboratory and 3% for field. (I.V.)

  7. Why can’t I measure the external quantum efficiency of the Ge subcell of my multijunction solar cell?

    Energy Technology Data Exchange (ETDEWEB)

    Barrigón, Enrique, E-mail: enrique.barrigon@ies-def.upm.es; Espinet-González, Pilar; Contreras, Yedileth; Rey-Stolle, Ignacio [Instituto de Energía Solar, Universidad Politécnica de Madrid ETSI de Telecomunicación, Avd. Complutense 30, 28040 Madrid (Spain)

    2015-09-28

    The measurement of the external quantum efficiency (EQE) of low bandgap subcells in a multijunction solar cell can be sometimes problematic. In particular, this paper describes a set of cases where the EQE of a Ge subcell in a conventional GaInP/GaInAs/Ge triple-junction solar cell cannot be fully measured. We describe the way to identify each case by tracing the I-V curve under the same light-bias conditions applied for the EQE measurement, together with the strategies that could be implemented to attain the best possible measurement of the EQE of the Ge subcell.

  8. Fabrication and electrical characterizations of graphene nanocomposite thin film based heterojunction diode

    Science.gov (United States)

    Rahim, Ishrat; Shah, Mutabar; Iqbal, Mahmood; Wahab, Fazal; Khan, Afzal; Khan, Shah Haider

    2017-11-01

    The use of graphene in electronic devices is becoming attractive due to its inherent scalability and is thus well suited for flexible electronic devices. Here we present the electrical characterization of heterojunction diode, based on the nanocomposite of graphene (G) with silver nanoparticles (Ag NPs), at room temperature. The diode was fabricated by depositing nanocomposite on the n-Si substrate. The current - voltage (I - V) characteristic of the fabricated junction shows rectifying behavior similar to a Schottky junction. The junction parameters such as ideality factor (n), series resistance (Rs), and barrier height (ϕb) has been extracted, using various methods, from the experimentally obtained I - V data. The measured values of n, Rs and ϕb are 3.86, 45 Ω and 0.367 eV, respectively, as calculated from the I - V curve. The numerical values of these parameters calculated by different methods are in good agreement with each other showing the consistency of the applied calculating techniques. The conduction mechanism of the fabricated diode seems to have been dominated by the Trap Charge Limited Conduction (TCLC) behavior. The energy distribution of interface states density determined from forward bias I - V characteristic shows an exponential decrease with bias from 27 × 1013 cm-2 eV-1 at (Ec - 0.345) eV to 3 × 1013 cm-2 eV-1at (Ec - 0.398) eV.

  9. Ion source plasma parameters measurement based on Langmuir probe with commercial frequency sweep

    International Nuclear Information System (INIS)

    Xie, Y.H.; Hu, C.D.; Liu, S.; Shong, S.H.; Jiang, C.C.; Liu, Z.M.

    2010-01-01

    Langmuir probe is one of the main diagnostic tools to measure the plasma parameters in the ion source. In this article, the commercial frequency power, which is sine wave of 50 Hz, was supplied on the Langmuir probe to measure the plasma parameters. The best feature of this probe sweep voltage is that it does not need extra design. The probe I-V characteristic curve can be got in less than 5 ms and the plasma parameters, the electron temperature and the electron density, varying with the time can be got in one plasma discharge of 400 ms.

  10. Noninvasive measurement of nutrient portal blood shunting: an experimental study with [14C]ursodeoxycholic acid

    International Nuclear Information System (INIS)

    Nordlinger, B.; Parquet, M.; Infante, R.; Moreels, R.; Blondiau, P.; Boschat, M.; Groussard, M.; Huguet, C.

    1982-01-01

    All of the methods proposed for measuring portal blood flow are either invasive, estimate total rather than nutrient flow, and none has proved reliable in cirrhotic patients. A method has been derived from pharmacokinetic principles used for the calculation of bioavailability of drugs according to the route of administration (i.v. or p.o.) and tested experimentally in 20 pigs. A tracer dose of [ 14 C]ursodeoxycholic acid, a biliary acid with a high-liver first-pass effect, is administered in the duodenum, and serial peripheral blood samples are taken. Later, the same dose of the same drug is administered i.v. The shunt fraction of portal blood F is obtained by the ratio of the areas under the plasma level vs. time curves (AUC) after p.o. and i.v. administrations: (see formula in text). The pigs were divided into three experimental groups. (i) Group I: undisturbed portal flow; (ii) Group II: total diversion of portal blood with an end-to-side portacaval shunt, and (iii) Group III: partial diversion of portal blood through a side-to-side portacaval shunt. Portal flow was measured during surgery with an electromagnetic flowmeter above and below the shunt and the degree of shunting calculated. Results show that the shunt fraction measured with ursodeoxycholic acid is well-correlated with hemodynamic data. No overlap between Groups I and III is observed. It is concluded that the shunt fraction of nutrient portal blood can be measured with this noninvasive method. Minute amounts of ursodeoxycholic acid were used in order to be completely metabolized by the liver, even in spite of hepatocellular dysfunction. Therefore, this method should be valid in cirrhotic patients and be useful to decide the type of portasystemic shunt to propose for the decompression of gastroesophageal varices

  11. Investigation of Electron Transport Across Vertically Grown CNTs Using Combination of Proximity Field Emission Microscopy and Scanning Probe Image Processing Techniques

    Science.gov (United States)

    Kolekar, Sadhu; Patole, Shashikant P.; Yoo, Ji-Beom; Dharmadhikari, Chandrakant V.

    2018-03-01

    Field emission from nanostructured films is known to be dominated by only small number of localized spots which varies with the voltage, electric field and heat treatment. It is important to develop processing methods which will produce stable and uniform emitting sites. In this paper we report a novel approach which involves analysis of Proximity Field Emission Microscopic (PFEM) images using Scanning Probe Image Processing technique. Vertically aligned carbon nanotube emitters have been deposited on tungsten foil by water assisted chemical vapor deposition. Prior to the field electron emission studies, these films were characterized by scanning electron microscopy, transmission electron microscopy, and Atomic Force Microscopy (AFM). AFM images of the samples show bristle like structure, the size of bristle varying from 80 to 300 nm. The topography images were found to exhibit strong correlation with current images. Current-Voltage (I-V) measurements both from Scanning Tunneling Microscopy and Conducting-AFM mode suggest that electron transport mechanism in imaging vertically grown CNTs is ballistic rather than usual tunneling or field emission with a junction resistance of 10 kΩ. It was found that I-V curves for field emission mode in PFEM geometry vary initially with number of I-V cycles until reproducible I-V curves are obtained. Even for reasonably stable I-V behavior the number of spots was found to increase with the voltage leading to a modified Fowler-Nordheim (F-N) behavior. A plot of ln(I/V3) versus 1/V was found to be linear. Current versus time data exhibit large fluctuation with the power spectral density obeying 1/f2 law. It is suggested that an analogue of F-N equation of the form ln(I/Vα) versus 1/V may be used for the analysis of field emission data, where α may depend on nanostructure configuration and can be determined from the dependence of emitting spots on the voltage.

  12. Electrochemically assisted mechanically controllable break junction studies on the stacking configurations of oligo(phenylene ethynylene)s molecular junctions

    International Nuclear Information System (INIS)

    Zheng, Jue-Ting; Yan, Run-Wen; Tian, Jing-Hua; Liu, Jun-Yang; Pei, Lin-Qi; Wu, De-Yin; Dai, Ke; Yang, Yang; Jin, Shan

    2016-01-01

    Highlights: • I-V characteristics of a series of oligo(phenylene ethynylene)s molecular junctions were measured. • Conductance values were found to be dependent on molecular length and substituent group. • The measured low conductance values were explained by theoretical calculations. • EC-MCBJ is feasible to fabricate and characterize molecular junctions. - Abstract: We demonstrate an electrochemically assisted mechanically controllable break junction (EC-MCBJ) approach for current-voltage characteristic (I-V curve) measurements of metal/molecule/metal junctions. A series of oligo(phenylene ethynylene)s compounds (OPEs), including those involving electron withdrawing substituent group and different backbone lengths, had been successfully designed, synthesized, and placed onto the fabricated nanogap to form molecular junctions. The observed evolution in the measured conductances of OPEs indicates that there is a dependence of conductance on molecular length and substituent group. Compared with those extracted from conductance histogram construction, the conductances of OPEs measured from I-V curves are considerably lower. Based on the transmission spectra of OPEs that calculated by density functional theory (DFT) combined with non-equilibrium Green’s function (NEGF) method, this difference was attributed to our distinct experimental operation, which may give rise to a stacking configuration of two OPE molecules.

  13. Electrical resistivity probes

    Science.gov (United States)

    Lee, Ki Ha; Becker, Alex; Faybishenko, Boris A.; Solbau, Ray D.

    2003-10-21

    A miniaturized electrical resistivity (ER) probe based on a known current-voltage (I-V) electrode structure, the Wenner array, is designed for local (point) measurement. A pair of voltage measuring electrodes are positioned between a pair of current carrying electrodes. The electrodes are typically about 1 cm long, separated by 1 cm, so the probe is only about 1 inch long. The electrodes are mounted to a rigid tube with electrical wires in the tube and a sand bag may be placed around the electrodes to protect the electrodes. The probes can be positioned in a borehole or on the surface. The electrodes make contact with the surrounding medium. In a dual mode system, individual probes of a plurality of spaced probes can be used to measure local resistance, i.e. point measurements, but the system can select different probes to make interval measurements between probes and between boreholes.

  14. Synthesis, characterization and charge transport mechanism of CdZnO nanorods

    International Nuclear Information System (INIS)

    Mahmoud, Waleed E.; Al-Ghamdi, A.A.; El-Tantawy, F.; Al-Heniti, S.

    2009-01-01

    ZnO and Cd-doped ZnO nanostructures were prepared by new facile method at 80 deg. C. XRD measurement indicated that both samples had typical hexagonal wurtzite structures. Transmission electron microscopy (TEM) measurement shows that rod-like crystals have been formed. EDX measurement confirms the incorporation of the cadmium ion into the crystalline lattice of ZnO and indicated that cadmium ions uniformly distributed on the surface of the rods. The doping with cadmium ions has a great influence on the optical properties of the ZnO. The electrical measurements of Cd-doped ZnO nanorod were measured. The current-voltage (I-V) characteristic curve revealed that the charge transport above 4 V is mainly non-linear due to grain boundary contribution. The complex impedance spectroscopy was confirmed that the grain boundary effect controls the charge transport mechanism through CdZnO ceramic material.

  15. Comparative study of electrical transport and magnetic measurements of Y3Ba5Cu8O18±δ and YBa2Cu3O7-δ compounds: intragranular and intergranular superconducting properties

    Science.gov (United States)

    Slimani, Y.; Hannachi, E.; Ben Salem, M. K.; Ben Azzouz, F.; Ben Salem, M.

    2018-02-01

    We compare the superconducting properties and flux pinning characteristics between YBa2Cu3O7-δ (called Y-123) and Y3Ba5Cu8O18±δ (called Y-358) compounds. Both samples were synthesized through the solid-state reaction. The samples were examined by X-ray diffraction, and scanning electron microscope coupled with energy dispersive spectrometry. The critical current densities of the prepared samples were investigated using current-voltage, magnetization measurements and ac-susceptibility. It is demonstrated that the Y-358 exhibits better superconducting and pinning properties than the Y-123 one. This may be ascribed to the layered structure and the occurrence of a greater number of insulating layers between the CuO2 planes that act as effective pinning sites and consequently conduce to a better fundamental pinning capacity in Y-358.

  16. Analysis of carrier transport and carrier trapping in organic diodes with polyimide-6,13-Bis(triisopropylsilylethynyl)pentacene double-layer by charge modulation spectroscopy and optical second harmonic generation measurement

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Eunju, E-mail: elim@dankook.ac.kr, E-mail: taguchi.d.aa@m.titech.ac.jp, E-mail: iwamoto@pe.titech.ac.jp [Department of Applied Physics, Institute of Nanosensor and Biotechnology, Dankook University, Jukjeon-dong, Gyeonggi-do 448-701 (Korea, Republic of); Taguchi, Dai, E-mail: elim@dankook.ac.kr, E-mail: taguchi.d.aa@m.titech.ac.jp, E-mail: iwamoto@pe.titech.ac.jp; Iwamoto, Mitsumasa, E-mail: elim@dankook.ac.kr, E-mail: taguchi.d.aa@m.titech.ac.jp, E-mail: iwamoto@pe.titech.ac.jp [Department of Physical Electronics, Tokyo Institute of Technology 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552 (Japan)

    2014-08-18

    We studied the carrier transport and carrier trapping in indium tin oxide/polyimide (PI)/6,13-Bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene)/Au diodes by using charge modulation spectroscopy (CMS) and time-resolved electric field induced optical second harmonic generation (TR-EFISHG) measurements. TR-EFISHG directly probes the spatial carrier behaviors in the diodes, and CMS is useful in explaining the carrier motion with respect to energy. The results clearly indicate that the injected carriers move across TIPS-pentacene thorough the molecular energy states of TIPS-pentacene and accumulate at the PI/TIPS-pentacene interface. However, some carriers are trapped in the PI layers. These findings take into account the capacitance-voltage and current-voltage characteristics of the diodes.

  17. Influence of the Ambient Electric Field on Measurements of the Actively Controlled Spacecraft Potential by MMS

    Science.gov (United States)

    Torkar, K.; Nakamura, R.; Andriopoulou, M.; Giles, B. L.; Jeszenszky, H.; Khotyaintsev, Y. V.; Lindqvist, P.-A.; Torbert, R. B.

    2017-12-01

    Space missions with sophisticated plasma instrumentation such as Magnetospheric Multiscale, which employs four satellites to explore near-Earth space benefit from a low electric potential of the spacecraft, to improve the plasma measurements and therefore carry instruments to actively control the potential by means of ion beams. Without control, the potential varies in anticorrelation with plasma density and temperature to maintain an equilibrium between the plasma current and the one of photoelectrons produced at the surface and overcoming the potential barrier. A drawback of the controlled, almost constant potential is the difficulty to use it as convenient estimator for plasma density. This paper identifies a correlation between the spacecraft potential and the ambient electric field, both measured by double probes mounted at the end of wire booms, as the main responsible for artifacts in the potential data besides the known effect of the variable photoelectron production due to changing illumination of the surface. It is shown that the effect of density variations is too weak to explain the observed correlation with the electric field and that a correction of the artifacts can be achieved to enable the reconstruction of the uncontrolled potential and plasma density in turn. Two possible mechanisms are discussed: the asymmetry of the current-voltage characteristic determining the probe to plasma potential and the fact that a large equipotential structure embedded in an electric field results in asymmetries of both the emission and spatial distribution of photoelectrons, which results in an increase of the spacecraft potential.

  18. Quality assessment of graphene: Continuity, uniformity,and accuracy of mobility measurements

    Institute of Scientific and Technical Information of China (English)

    David M.A.Mackenzie; Timothy J.Booth; Lene Gammelgaard; Johanna Zultak; Bjarke S.Jessen; Peter Bφggild; Dirch H.Petersen; Jonas D.Buron; Patrick R.Whelan; José M.Caridad; Martin Bjergfelt; Birong Luo; Abhay Shivayogimath; Anne L.Smitshuysen; Joachim D.Thomsen

    2017-01-01

    With the increasing availability of large-area graphene,the ability to rapidly and accurately assess the quality of the electrical properties has become critically important.For practical applications,spatial variability in carrier density and carrier mobility must be controlled and minimized.We present a simple framework for assessing the quality and homogeneity of large-area graphene devices.The field effect in both exfoliated graphene devices encapsulated in hexagonal boron nitride and chemical vapor-deposited (CVD) devices was measured in dual current-voltage configurations and used to derive a single,gate-dependent effective shape factor,β,for each device.β is a sensitive indicator of spatial homogeneity that can be obtained from samples of arbitrary shape.All 50 devices investigated in this study show a variation (up to tenfold) inβ as a function of the gate bias.Finite element simulations suggest that spatial doping inhomogeneity,rather than mobility inhomogeneity,is the primary cause of the gate dependence ofβ,and that measurable variations ofβ can be caused by doping variations as small as 1010 cm-2.Our results suggest that local variations in the position of the Dirac point alter the current flow and thus the effective sample shape as a function of the gate bias.We also found that such variations lead to systematic errors in carrier mobility calculations,which can be revealed by inspecting the correspondingβ factor.

  19. A silicon-on-insulator vertical nanogap device for electrical transport measurements in aqueous electrolyte solution

    Energy Technology Data Exchange (ETDEWEB)

    Strobel, Sebastian [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany); Arinaga, Kenji [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany); Hansen, Allan [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany); Tornow, Marc [Walter Schottky Institut, Technische Universitaet Muenchen, Am Coulombwall, D-85748 Garching (Germany)

    2007-07-25

    A novel concept for metal electrodes with few 10 nm separation for electrical conductance measurements in an aqueous electrolyte environment is presented. Silicon-on-insulator (SOI) material with 10 nm buried silicon dioxide serves as a base substrate for the formation of SOI plateau structures which, after recess-etching the thin oxide layer, thermal oxidation and subsequent metal thin film evaporation, feature vertically oriented nanogap electrodes at their exposed sidewalls. During fabrication only standard silicon process technology without any high-resolution nanolithographic techniques is employed. The vertical concept allows an array-like parallel processing of many individual devices on the same substrate chip. As analysed by cross-sectional TEM analysis the devices exhibit a well-defined material layer architecture, determined by the chosen material thicknesses and process parameters. To investigate the device in aqueous solution, we passivated the sample surface by a polymer layer, leaving a micrometre-size fluid access window to the nanogap region only. First current-voltage characteristics of a 65 nm gap device measured in 60 mM buffer solution reveal excellent electrical isolation behaviour which suggests applications in the field of biomolecular electronics in a natural environment.

  20. Influence of Pentacene Interface Layer in ITO/α-NPD/Alq3/Al Organic Light Emitting Diodes by Time-Resolved Electric-Field-Induced Optical Second-Harmonic Generation Measurement.

    Science.gov (United States)

    Oda, Yoshiaki; Sadakata, Atsuo; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2016-04-01

    By using I-V, EL-V, displacement current measurement (DCM) and time-resolved electric-field-induced optical second-harmonic generation (TR-EFISHG) measurement, we studied the influence of interface pentacene layer inserted between ITO and a-NPD layers in ITO/α-NPD/Alq3/Al OLEDs. All experiments were carried out for the OLEDs with and without a pentacene interface layer. The I-V and EL-V measurements showed the decrease of operating voltage of EL, the DCM showed the lowering of inception voltage of carrier injection by inserting a pentacene interface layer. The TR-EFISHG measurement showed the faster accumulation of holes at the interface between the a-NPD and Alq3 layers, which resulted in the relaxation of electric field of a-NPD layer accomplished by the increase of the conductivity and the increase of the electric field in the Alq3 layer. We conclude that TR-EFISHG measurement is helpful for understanding I-V and EL-V characteristics, and can be combined with other methods to give significant information which are impacted by the interface layer.

  1. Forward Current Transport Mechanisms of Ni/Au—InAlN/AlN/GaN Schottky Diodes

    Science.gov (United States)

    Wang, Xiao-Feng; Shao, Zhen-Guang; Chen, Dun-Jun; Lu, Hai; Zhang, Rong; Zheng, You-Dou

    2014-05-01

    We fabricate two Ni/Au-In0.17Al0.83N/AlN/GaN Schottky diodes on substrates of sapphire and Si, respectively, and investigate their forward-bias current transport mechanisms by temperature-dependent current-voltage measurements. In the temperature range of 300-485 K, the Schottky barrier heights (SBHs) calculated by using the conventional thermionic-emission (TE) model are strongly positively dependent on temperature, which is in contrast to the negative-temperature-dependent characteristic of traditional semiconductor Schottky diodes. By fitting the forward-bias I-V characteristics using different current transport models, we find that the tunneling current model can describe generally the I-V behaviors in the entire measured range of temperature. Under the high forward bias, the traditional TE mechanism also gives a good fit to the measured I-V data, and the actual barrier heights calculated according to the fitting TE curve are 1.434 and 1.413 eV at 300K for InAlN/AlN/GaN Schottky diodes on Si and the sapphire substrate, respectively, and the barrier height shows a slightly negative temperature coefficient. In addition, a formula is given to estimate SBHs of Ni/Au—InAlN/AlN/GaN Schottky diodes taking the Fermi-level pinning effect into account.

  2. Measurements of plasma profiles using a fast swept Langmuir probe in the VINETA-II magnetic reconnection experiment

    Science.gov (United States)

    Shesterikov, I.; Von Stechow, A.; Grulke, O.; Stenzel, R.; Klinger, T.

    2017-07-01

    A fast-swept Langmuir probe capable to be biased at a high voltages has been constructed and successfully operated at the VINETA-II magnetic reconnection experiment. The presented circuit has two main features beneficial for fast transient parameter changes in laboratory experiments as, e.g., plasma guns or magnetic reconnection: the implementation simplicity and the high voltage sweep range. This work presents its design and performance for time-dependent measurements of VINETA-II plasmas. The probe is biased with a sinusoidal voltage at a fixed frequency. Current - voltage characteristics are measured along the falling and rising slopes of the probe bias. The sweep frequency is fsweep= 150 kHz. The spatiotemporal evolution of radial plasma profiles is obtained by evaluation of the probe characteristics. The plasma density measurements agree with those derived from a microwave interferometer, demonstrating the reliability of the measurements. As a model plasma system, a plasma gun discharge with typical pulse times of 60 μ s is chosen.

  3. A Multi-Functional Microelectrode Array Featuring 59760 Electrodes, 2048 Electrophysiology Channels, Stimulation, Impedance Measurement and Neurotransmitter Detection Channels.

    Science.gov (United States)

    Dragas, Jelena; Viswam, Vijay; Shadmani, Amir; Chen, Yihui; Bounik, Raziyeh; Stettler, Alexander; Radivojevic, Milos; Geissler, Sydney; Obien, Marie; Müller, Jan; Hierlemann, Andreas

    2017-06-01

    Biological cells are characterized by highly complex phenomena and processes that are, to a great extent, interdependent. To gain detailed insights, devices designed to study cellular phenomena need to enable tracking and manipulation of multiple cell parameters in parallel; they have to provide high signal quality and high spatiotemporal resolution. To this end, we have developed a CMOS-based microelectrode array system that integrates six measurement and stimulation functions, the largest number to date. Moreover, the system features the largest active electrode array area to date (4.48×2.43 mm 2 ) to accommodate 59,760 electrodes, while its power consumption, noise characteristics, and spatial resolution (13.5 μm electrode pitch) are comparable to the best state-of-the-art devices. The system includes: 2,048 action-potential (AP, bandwidth: 300 Hz to 10 kHz) recording units, 32 local-field-potential (LFP, bandwidth: 1 Hz to 300 Hz) recording units, 32 current recording units, 32 impedance measurement units, and 28 neurotransmitter detection units, in addition to the 16 dual-mode voltage-only or current/voltage-controlled stimulation units. The electrode array architecture is based on a switch matrix, which allows for connecting any measurement/stimulation unit to any electrode in the array and for performing different measurement/stimulation functions in parallel.

  4. Obtaining Laws through Quantifying Experiments: Justifications of Pre-Service Physics Teachers in the Case of Electric Current, Voltage and Resistance

    Science.gov (United States)

    Mäntylä, Terhi; Hämäläinen, Ari

    2015-01-01

    The language of physics is mathematics, and physics ideas, laws and models describing phenomena are usually represented in mathematical form. Therefore, an understanding of how to navigate between phenomena and the models representing them in mathematical form is important for a physics teacher so that the teacher can make physics understandable…

  5. Surface potential distribution and airflow performance of different air-exposed electrode plasma actuators at different alternating current/direct current voltages

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Liang; Yan, Hui-Jie; Qi, Xiao-Hua; Hua, Yue; Ren, Chun-Sheng, E-mail: rchsh@dlut.edu.cn [School of Physics and Optoelectronic Technology, Key laboratory of Materials Modification by Laser, Ion and Electron Beams, Ministry of Education, Dalian University of Technology, Dalian 116023 (China)

    2015-04-15

    Asymmetric surface dielectric barrier discharge (SDBD) plasma actuators have been intensely studied for a number of years due to their potential applications for aerodynamic control. In this paper, four types of actuators with different configurations of exposed electrode are proposed. The SDBD actuators investigated are driven by dual-power supply, referred to as a fixed AC high voltage and an adjustable DC bias. The effects of the electrode structures on the dielectric surface potential distribution, the electric wind velocity, and the mean thrust production are studied, and the dominative factors of airflow acceleration behavior are revealed. The results have shown that the actions of the SDBD actuator are mainly dependent on the geometry of the exposed electrode. Besides, the surface potential distribution can effectively affect the airflow acceleration behavior. With the application of an appropriate additional DC bias, the surface potential will be modified. As a result, the performance of the electric wind produced by a single SDBD can be significantly improved. In addition, the work also illustrates that the actuators with more negative surface potential present better mechanical performance.

  6. Current-voltage characteristics of SnO2-Co3O4-Cr2O3-Sb2O5 ceramics

    International Nuclear Information System (INIS)

    Aguilar-Martinez, J A; Glot, A B; Gaponov, A V; Hernandez, M B; Guerrero-Paz, J

    2009-01-01

    The effect of mechanical treatment in a planetary mill on the microstructure and electrical properties of tin dioxide based varistor ceramics in the system SnO 2 -Co 3 O 4 -Cr 2 O 3 -Sb 2 O 5 sintered in the range 1150-1450 0 C was studied. The mechanical treatment leads to an increase in shrinkage, decrease in porosity, decrease in sample diameter, change in colour of the sintered samples from grey to black and enhancement of nonlinearity. For the sample sintered at 1350 0 C the mechanical treatment enhances the nonlinearity coefficient from 11 to 31 and decreases the electric field E 1 (at 10 -3 A cm -2 ) from 3500 to 2800 V cm -1 . The observed changes in physical properties are explained in terms of an additional size reduction of oxide particles and a better mixing of oxide powder followed by the formation of potential barriers at the grain boundaries throughout the whole sample. In spite of the low porosity, the low-field electrical conductivity of mechanically treated ceramics is significantly increased with the growth of relative humidity. A higher humidity sensitivity is found for mechanically treated ceramics with higher barrier height and higher nonlinearity coefficient.

  7. Understanding S-Shaped Current-Voltage Characteristics in Organic Solar Cells Containing a TiOx Inter layer with Impedance Spectroscopy and Equivalent Circuit Analysis

    NARCIS (Netherlands)

    Ecker, Bernhard; Egelhaaf, Hans-Joachim; Steim, Roland; Parisi, Juergen; von Hauff', Elizabeth

    2012-01-01

    In this study we propose an equivalent circuit model to describe S-shaped current–voltage (I–V) characteristics in inverted solar cells with a TiOx interlayer between the cathode and the poly(3-hexylthiophene):[6,6]-phenyl C61 butyric acid methyl ester active layer. Initially the solar cells

  8. Surface potential distribution and airflow performance of different air-exposed electrode plasma actuators at different alternating current/direct current voltages

    International Nuclear Information System (INIS)

    Yang, Liang; Yan, Hui-Jie; Qi, Xiao-Hua; Hua, Yue; Ren, Chun-Sheng

    2015-01-01

    Asymmetric surface dielectric barrier discharge (SDBD) plasma actuators have been intensely studied for a number of years due to their potential applications for aerodynamic control. In this paper, four types of actuators with different configurations of exposed electrode are proposed. The SDBD actuators investigated are driven by dual-power supply, referred to as a fixed AC high voltage and an adjustable DC bias. The effects of the electrode structures on the dielectric surface potential distribution, the electric wind velocity, and the mean thrust production are studied, and the dominative factors of airflow acceleration behavior are revealed. The results have shown that the actions of the SDBD actuator are mainly dependent on the geometry of the exposed electrode. Besides, the surface potential distribution can effectively affect the airflow acceleration behavior. With the application of an appropriate additional DC bias, the surface potential will be modified. As a result, the performance of the electric wind produced by a single SDBD can be significantly improved. In addition, the work also illustrates that the actuators with more negative surface potential present better mechanical performance

  9. Transport in nanoparticle chains influenced by reordering

    International Nuclear Information System (INIS)

    Luedtke, T.; Mirovsky, P.; Huether, R.; Govor, L.; Bauer, G.H.; Parisi, J.; Haug, R.J.

    2011-01-01

    Nanoparticles are deposited onto a mica substrate in a dewetting process of hexane solution containing the nanoparticles. The array of nanoparticles was measured inside an electron beam microscope containing a self-developed probing-tip setup. Transport measurements performed under vacuum conditions at room temperature show a power law behavior as expected for low-dimensional cluster systems. During the measurement a variation of the threshold voltage in the nonlinear current-voltage (I-V) characteristic was observed which we attribute to a reordering of the system by an applied electric field. - Highlights: → Fabrication of chains of ordered Au-nanoparticles. → Contact these nanoparticles without further chemical treatment with probing tips inside an electron microscope. → Observation of low-dimensional transport and Coulomb blockade. → Reordering of nanoparticles due to the applied electric field between the tips.

  10. Density of interface states, excess capacitance and series resistance in the metal-insulator-semiconductor (MIS) solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Altindal, Semsettin; Tataroglu, Adem; Dokme, Ilbilge [Faculty of Arts and Sciences, Physics Department, Gazi University, 06500, Ankara (Turkey)

    2005-01-31

    Dark and illuminated current-voltage (I-V) characteristics of Al/SiO{sub x}/p-Si metal-insulator-semiconductor (MIS) solar cells were measured at room temperature. In addition to capacitance-voltage (C-V) and conductance-voltage (G-V), characteristics are studied at a wide frequency range of 1kHz-10MHz. The dark I-V characteristics showed non-ideal behavior with an ideal factor of 3.2. The density of interface states distribution profiles as a function of (E{sub ss}-E{sub v}) deduced from the I-V measurements at room temperature for the MIS solar cells on the order of 10{sup 13}cm{sup -2}eV{sup -1}. These interface states were responsible for the non-ideal behavior of I-V, C-V and G-V characteristics. Frequency dispersion in capacitance for MIS solar cells can be interpreted only in terms of interface states. The interface states can follow the a.c. signal and yield an excess capacitance, which depends on the relaxation time of interface states and the frequency of the a.c. signal. It was observed that the excess capacitance C{sub o} caused by an interface state decreases with an increase of frequency. The capacitances characteristics of MIS solar cells are affected not only in interface states but also series resistance. Analysis of this data indicated that the high interface states and series resistance leads to lower values of open-circuit voltage, short-circuit current density, and fill factor. Experimental results show that the location of interface states and series resistance have a significant effect on I-V, C-V and G-V characteristics.

  11. Nitrogen plasma-treated multilayer graphene-based field effect transistor fabrication and electronic characteristics

    Science.gov (United States)

    Su, Wei-Jhih; Chang, Hsuan-Chen; Honda, Shin-ichi; Lin, Pao-Hung; Huang, Ying-Sheng; Lee, Kuei-Yi

    2017-08-01

    Chemical doping with hetero-atoms is an effective method used to change the characteristics of materials. Nitrogen doping technology plays a critical role in regulating the electronic properties of graphene. Nitrogen plasma treatment was used in this work to dope nitrogen atoms to modulate multilayer graphene electrical properties. The measured I-V multilayer graphene-base field-effect transistor characteristics (GFETs) showed a V-shaped transfer curve with the hole and electron region separated from the measured current-voltage (I-V) minimum. GFETs fabricated with multilayer graphene from chemical vapor deposition (CVD) exhibited p-type behavior because of oxygen adsorption. After using different nitrogen plasma treatment times, the minimum in I-V characteristic shifted into the negative gate voltage region with increased nitrogen concentration and the GFET channel became an n-type semiconductor. GFETs could be easily fabricated using this method with potential for various applications. The GFET transfer characteristics could be tuned precisely by adjusting the nitrogen plasma treatment time.

  12. Substrate temperature effects on reactively sputtered Cr2O3/n-Si heterojunctions

    International Nuclear Information System (INIS)

    Ocak, Yusuf Selim; Genisel, Mustafa Fatih; Issa, Ali Ahmed; Tombak, Ahmet; Kilicoglu, Tahsin

    2016-01-01

    To see the effects of substrate temperature on Cr 2 O 3 /n-Si heterojunctions, Cr 2 O 3 thin films were formed on n-Si and glass substrates at 40, 150 and 250 °C by radio frequency (RF) reactive sputtering technique. High purity Cr was used as target and oxygen was used as reactive gas. Optical properties of Cr 2 O 3 /n-Si thin films were analyzed using UV-vis data. The band gaps of the films were compared. The electrical properties of Cr 2 O 3 /n-Si heterojunction were tested by their current voltage ( I-V ) measurements in dark. It was observed that the heterojunction which was fabricated by forming Cr 2 O 3 thin film at 250 °C gave better rectification. The characteristic electrical parameters such as barrier height, ideality factor and series resistance were calculated by using its I-V data. The influence of light intensity on photovoltaic effect behavior of the device was also calculated, finally the barrier height value of the structure obtained from capacitance-voltage ( C-V ) data were compared with the one calculated from I-V measurements. (paper)

  13. Electrical and photoelectrical characteristic investigation of a new generation photodiode based on bromothymol blue dye

    International Nuclear Information System (INIS)

    Imer, A Gencer; Korkut, A; Tombak, A

    2016-01-01

    Bromothymol blue (BTB) with the molecular formula of C 27 H 28 Br 2 O 5 S was grown onto p-Si substrate to fabricate heterojunction by spin coating technique. The current voltage ( I-V ) measurements of diode were carried out in dark and under different illumination intensity at room temperature. The photoelectrical properties of heterojunction based on BTB were investigated using the illumination intensity dependent I-V data. The results showed that photo current of diode increases with the increase in light intensity. Also, the electrical parameters of device were determined via I-V, and capacitance- voltage ( C-V ), conductance-voltage ( G-V ) measurements at different frequencies. It is observed that the excess capacitance is created at low frequencies due to the contribution of interface states charge which can follow the alternative current signal to capacitance. It is stated that, both the electrical and photoelectrical parameters of diode can be changed, and also the performance of the device could be affected by the organic thin film interlayer. (paper)

  14. Analysis of electrical properties of heterojunction based on ZnIn2Se4

    Science.gov (United States)

    Attia, A. A.; Ali, H. A. M.; Salem, G. F.; Ismail, M. I.; Al-Harbi, F. F.

    2017-04-01

    Heterojunction of n-ZnIn2Se4/p-Si was fabricated using thermal evaporation of ZnIn2Se4 thin films of thickness 473 nm onto p-Si substrate at room temperature. The characteristics of current-voltage (I-V) for n-ZnIn2Se4/p-Si heterojunction were investigated at different temperatures ranged from 308 K to 363 K. The junction parameters namely are; rectification ratio (RR), series resistance (Rs), shunt resistance (Rsh) and diode ideality factor (n) were calculated from the analysis of I-V curves. The forward current showed two conduction mechanisms operating, which were the thermionic emission and the single trap space charge limited current in low (0 ≤ V ≤ 0.5 V) and high (V ≥ 0.7 V) ranges of voltage, respectively. The reverse current was due to the generation through Si rather than the ZnIn2Se4 film. The built-in voltage and the width of the depletion region were determined from the capacitance-voltage (C-V) measurements. The photovoltaic characteristics of the junction were also studied through the (I-V) measurements under illumination of 40 mW/cm2. The cell parameters; the short-circuit current, the open-circuit voltage and the fill factor were estimated at room temperature.

  15. Application of LBIC measurements for characterisation of triple junction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Kwarikunda, N., E-mail: Nicholas.kwarikunda@live.nmmu.ac.za [Nelson Mandela Metropolitan University, P.O. BOX 77000, Port Elizabeth, 6031 (South Africa); Makerere University, P.O. BOX 7062, Kampala (Uganda); Dyk, E.E. van; Vorster, F.J. [Nelson Mandela Metropolitan University, P.O. BOX 77000, Port Elizabeth, 6031 (South Africa); Okullo, W. [Makerere University, P.O. BOX 7062, Kampala (Uganda); Munji, M.K. [Kenyatta University, P.O. BOX 43844-00100, Nairobi (Kenya)

    2014-04-15

    In this study the Light Beam Induced Current (LBIC) imaging technique was used to characterise InGaP/InGaAs/Ge triple junction solar cells. The study focused on the use of monochromatic and solar light as beam probes to obtain photocurrent response maps from which the presence of any current reducing features on the solar cell were identified. Point illuminated current voltage (I–V) curves were obtained simultaneously while LBIC scanning measurements were being made. Curve fitting using an interval division algorithm based on the single diode model was performed to extract basic point device and performance parameters to give a rough indication of the functioning of the triple junction device. Using red and blue lasers as beam probes, reverse voltage breakdown was observed on the I–V curves which could be attributed to the Ge bottom subcell not being fully activated. The extracted parameters obtained when using monochromatic and solar light beam probes showed a large variation, indicating the dependence of I–V parameters on the spectral content of the beam probe.

  16. Application of LBIC measurements for characterisation of triple junction solar cells

    International Nuclear Information System (INIS)

    Kwarikunda, N.; Dyk, E.E. van; Vorster, F.J.; Okullo, W.; Munji, M.K.

    2014-01-01

    In this study the Light Beam Induced Current (LBIC) imaging technique was used to characterise InGaP/InGaAs/Ge triple junction solar cells. The study focused on the use of monochromatic and solar light as beam probes to obtain photocurrent response maps from which the presence of any current reducing features on the solar cell were identified. Point illuminated current voltage (I–V) curves were obtained simultaneously while LBIC scanning measurements were being made. Curve fitting using an interval division algorithm based on the single diode model was performed to extract basic point device and performance parameters to give a rough indication of the functioning of the triple junction device. Using red and blue lasers as beam probes, reverse voltage breakdown was observed on the I–V curves which could be attributed to the Ge bottom subcell not being fully activated. The extracted parameters obtained when using monochromatic and solar light beam probes showed a large variation, indicating the dependence of I–V parameters on the spectral content of the beam probe.

  17. Density, temperature, and potential fluctuation measurements by the swept Langmuir probe technique in Wendelstein 7-AS

    International Nuclear Information System (INIS)

    Giannone, L.; Balbin, R.; Niedermeyer, H.; Endler, M.; Herre, G.; Hidalgo, C.; Rudyj, A.; Theimer, G.; Verplanke, P.

    1994-01-01

    In the Wendelstein 7-AS stellarator (W7-AS) [Plasma Phys. Controlled Fusion 33, 1591 (1991)], current-voltage characteristics of the Langmuir probe at sweep frequencies in the range 400 kHz to 1 MHz were measured and it was found that the mean and fluctuation values of the ion saturation current, floating potential, and electron temperature were independent of the sweep frequency. A radial scan in the vicinity of the velocity shear layer was performed. The simultaneous sweeping of 3 probe tips showed a statistically significant spatial coherence of the fluctuations in the poloidal direction and a decrease in spatial coherence of the fluctuations with increasing tip separation could be demonstrated. The observation of a change in the propagation direction of fluctuations as the shear layer was crossed and a calculation of the transport spectrum show that the swept probe method is capable of reproducing known results. Apparent temperature fluctuations, due to variations of density and potential during a sweep, are shown by simulations to be only of importance at frequencies above half the Nyquist frequency

  18. Analysis of School Leaders Licensure Assessment Content Category I-V Scores and Principal Internship Self-Assessment Scores for ISLLC Standards I-V

    Science.gov (United States)

    Kelly, Michael D.

    2016-01-01

    This study compares School Leaders Licensure Assessment (SLLA) sub-scores with principal interns' self-assessment sub-scores (ISA) for a principal internship evaluation instrument in one educational leadership graduate program. The results of the study will be used to help establish the effectiveness of the current principal internship program,…

  19. Noise measurements of YBa2Cu3O7 thin film high-temperature superconductors

    International Nuclear Information System (INIS)

    Hall, J.J.

    1992-01-01

    The characteristics of thin-film YBa2Cu3O7 superconductors were studied from the superconducting region through the transition region and into the normal region. The properties studied included the resistance-temperature, current-voltage, and electrical noise with concentration of measurements in the transition region. The resistance vs. temperature measurements show a zero resistance followed by a small rise in magnitude at the onset of resistance followed by a sharp increase until the resistance tapers off in the fully normal region. The a-axis films had a larger normal resistivity, a lower critical temperature, and a broader transition than the similar c-axis films. The current(I) - voltage(V) measurements were concentrated in the transition region. A power relation between I and V was found to be V varies as I a(T) where a(T) is temperature dependent starting high the onset of vortex formation, approaches 3 at the vortex unbinding temperature, and goes to 1 when fully normal. This behavior was predicted by the Kosterlitz-Thouless theory and was found experimentally in all four films measured. The current-induced electrical noise characteristics were measured for four samples varying in thickness and axis orientation. Each film exhibited a widely varying magnitude of the noise voltage spectral density (S V ) in the transition region with a leveling off when fully normal. The normalized noise (S V /V squared) showed a sharp decrease in magnitude from the onset of measurable noise continually decreasing until flattening out when fully normal. The a-axis films exhibited S V /V squared over 3 order of magnitude larger than the c-axis films in the transition and normal regions. The normalized temperature coefficient of resistance (beta) was plotted against S V /V squared on a log-log scale to see if the noise generated was due to temperature fluctuations (slope = 2)

  20. Importance measures

    International Nuclear Information System (INIS)

    Gomez Cobo, A.

    1997-01-01

    The presentation discusses the following: general concepts of importance measures; example fault tree, used to illustrate importance measures; Birnbaum's structural importance; criticality importance; Fussel-Vesely importance; upgrading function; risk achievement worth; risk reduction worth

  1. Formative (measurement)

    NARCIS (Netherlands)

    Fassott, G.; Henseler, Jörg; Cooper, C.; Lee, N.; Farrell, A.

    2015-01-01

    When using measurement models with multiple indicators, researchers need to decide about the epistemic relationship between the latent variable and its indicators. In this article, we describe the nature, the estimation, the characteristics, and the validity assessment of formative measurement

  2. Measurement evaluation

    CERN Document Server

    Boros, A

    1990-01-01

    The information obtained about a measured object is called ``crude'' measurement information and must be related to the conditions under which the measurement took place. Using ``crude'' measurement information as a starting point, evaluation produces physically correctly interpreted data with their estimated (or corrected) error. Although a number of works deal with the evaluation of measurements, they either appeared a long time ago or serve essentially different aims. This book gives a comprehensive and current overview on the basic principles, aids, devices, and methods in the eval

  3. Download this PDF file

    African Journals Online (AJOL)

    Vz(nkT/qu)J (2). ,which is Ohm's Law. In such a case the I-V curve becomes symmetric and linear (ohmic). However, if the current-voltage characteristics is such that it is neither J > >. Jo, nor 1 < < Jo, i.e., intermediate between the two limits, then the I-V curve becomes non—ohmic and non-rectifying. It is symmetrical and ...

  4. Ab initio calculation of contact effects on electron transport through single molecules by the RTM/NEGF method

    International Nuclear Information System (INIS)

    Hirose, Kenji; Kobayashi, Nobuhiko

    2006-01-01

    Using the recursion-transfer-matrix (RTM) method combined with the nonequilibrium Green's function (NEGF) method, we study the electronic states and current-voltage (I-V) characteristics of atomic-scale nanocontact systems. We find that non-linear behaviors appear in the I-V characteristics even without molecules between electrodes. Such non-linear behaviors emerge when the nanocontacts are not well constructed and the transport properties change from tunneling to ballistic regimes

  5. Low resistance and transparent Ag/AZO ohmic contact to p-GaN

    International Nuclear Information System (INIS)

    Han, T.; Wang, T.; Gan, X. W.; Wu, H.; Shi, Y.; Liu, C.

    2014-01-01

    Silver (Ag)/ aluminum-doped zinc oxide (AZO) films were deposited on p-GaN by using electron beam evaporation. After the annealing process, current -voltage (I-V) measurements were carried out to determine the characteristic of the contacts. The Ag/AZO films annealed at 600 .deg. C were found to present an ohmic contact behavior. The specific contact resistance was calculated to be 9.76 x 10 -4 Ωcm 2 and the transmittance was over 80% for visibly light. The atomic force microscope was used to measure the aggregation of Ag grains which may have been the main factor in the formation of the Ag/AZO ohmic contact to p-GaN.

  6. Superconducting phase of YBa2Cu3O7-δ films in high magnetic fields: Vortex glass or Bose glass

    International Nuclear Information System (INIS)

    Woeltgens, P.J.M.; Dekker, C.; Swueste, J.; de Wijn, H.W.

    1993-01-01

    Nonlinear current-voltage (I-V) curves are measured in laser-ablated YBa 2 Cu 3 O 7-δ films deposited onto SrTiO 3 . The measurements are performed near the glass phase transition in a magnetic field of 5 T at various angles from the c axis. From a critical scaling analysis, the angular dependencies of the glass transition temperature and the critical glass exponents are extracted. At small angles, these results distinguish between a vortex glass, caused by random pointlike disorder, and a Bose glass, caused by linelike disorder. The results can be understood in terms of the vortex-glass model only. No evidence is found for the existence of a Bose-glass phase

  7. Effect of R.F. Power to the Structural Properties of ZnO Thin Films Deposited by Magnetron Sputtering

    International Nuclear Information System (INIS)

    Sin, N.D.M.; Rusop, M.

    2011-01-01

    The effect of RF power variation (100 watt∼400 watt ) on the zinc oxide (ZnO) thin films electrical, optical and structural properties were examined using current voltage (I-V) measurement, UV-Vis-NIR spectrophotometer, x-ray diffraction (XRD) and atomic force microscope (AFM). ZnO thin films were prepared at room temperature in pure argon atmosphere by a RF magnetron sputtering using ZnO target. The resistivity of thin film show the lowest at 300 watt. The absorption coefficient spectra obtained from UV-Vis-NIR spectrophotometer measurement show all films have low absorbance in visible and near infrared (IR) region but have high UV absorption properties using UV-VIS spectrophotometer (JASCO 670) . Highly oriented ZnO thin films [002] direction were obtained by using Rigaku Ultima IV. (author)

  8. Resistive switching of Cu/Cu2O junction fabricated using simple thermal oxidation at 423 K for memristor application

    Science.gov (United States)

    Ani, M. H.; Helmi, F.; Herman, S. H.; Noh, S.

    2018-01-01

    Recently, extensive researches have been done on memristor to replace current memory storage technologies. Study on active layer of memristor mostly involving n-type semiconductor oxide such as TiO2 and ZnO. This paper highlight a simple water vapour oxidation method at 423 K to form Cu/Cu2O electronic junction as a new type of memristor. Cu2O is a p-type semiconductor oxide, was used as the active layer of memristor. Cu/Cu2O/Au memristor was fabricated by thermal oxidation of copper foil, followed by sputtering of gold. Structural, morphological and memristive properties were characterized using XRD, FESEM, and current-voltage, I-V measurement respectively. Its memristivity was indentified by pinch hysteresis loop and measurement of high resistance state (HRS) and low resistance state (LRS) of the sample. The Cu/Cu2O/Au memristor demonstrates comparable performances to previous studies using other methods.

  9. Ion induced intermixing and consequent effects on the leakage currents in HfO{sub 2}/SiO{sub 2}/Si systems

    Energy Technology Data Exchange (ETDEWEB)

    Manikanthababu, N.; Saikiran, V.; Pathak, A.P.; Rao, S.V.S.N. [University of Hyderabad, School of Physics, Hyderabad (India); Chan, T.K.; Vajandar, S.; Osipowicz, T. [National University of Singapore, Department of Physics, Centre for Ion Beam Applications (CIBA), Singapore (Singapore)

    2017-05-15

    Atomic layer deposited (ALD) samples with layer stacks of HfO{sub 2} (3 nm)/SiO{sub 2} (0.7 nm)/Si were subjected to 120 MeV Au ion irradiation at different fluences to study intermixing effects across the HfO{sub 2}/SiO{sub 2} interface. High-resolution Rutherford backscattering spectrometry (HRBS) and X-ray reflectivity (XRR) measurements confirm an increase in the interlayer thickness as a result of SHI induced intermixing effects. Current-voltage (I-V) measurements reveal an order of magnitude difference in the leakage current density between the pristine and irradiated samples. This can be explained by considering the increased physical thickness of interlayer (HfSiO). Furthermore, the samples were subjected to rapid thermal annealing (RTA) process to analyze annealing kinetics. (orig.)

  10. Superconducting and normal state properties of niobium-potasium chloride composites

    International Nuclear Information System (INIS)

    Boysel, R.M.

    1981-01-01

    The electrical resistivity, current-voltage characteristics, critical currents, and DC magnetic susceptibility of composites consisting of 50 μm grains of Nb randomly dispersed in a KCl medium were measured. Data were taken between 1.2K and 20K in magnetic fields from 0 to +- 5G. The resistivity and current-voltage characteristics were measured using a standard four-terminal AC technique with a voltage sensitivity of 1 to 2nV, and the magnetic susceptibility was measured using an rf SQUID magnetometer. We found that samples with rho/sub n/ 2 . For 0.1Ω-cm 10Ω-cm there was no superconducting transition. The susceptibility decreased slowly below the grain transition temperature T/sub infinity/ and even below T/sub c/ in samples which underwent resistive transitions. The shape of the resistive transitions and the kink structure in the I-V's require a phase coherent transition model to adequately describe them. However, the poor fit of the theory to our data, the existence of the voltage steps, and the changing susceptibility below the resistive transition indicate that sample disorder plays a more important role in the superconducting transition of composites than is currently accounted for by phase coherent transition theories

  11. Fabrication and characterization of a CuO/ITO heterojunction with a graphene transparent electrode

    Science.gov (United States)

    Mageshwari, K.; Han, Sanghoo; Park, Jinsub

    2016-05-01

    In this paper, we investigate the electrical properties of a CuO-ITO heterojunction diode with the use of a graphene transparent electrode by current-voltage (I-V) characteristics. CuO thin films were deposited onto an ITO substrate by a simple sol-gel spin coating method and annealed at 500 °C. The x-ray diffraction pattern of the CuO thin films revealed the polycrystalline nature of CuO and exhibited a monoclinic crystal structure. FESEM images showed a uniform and densely packed particulate morphology. The optical band gap of CuO thin films estimated using UV-vis absorption spectra was found to be 2.50 eV. The I-V characteristics of the fabricated CuO-ITO heterojunction showed a well-defined rectifying behavior with improved electrical properties after the insertion of graphene. The electronic parameters of the heterostructure such as barrier height, ideality factor and series resistance were determined from the I-V measurements, and the possible current transport mechanism was discussed.

  12. Shunt resistance and saturation current determination in CdTe and CIGS solar cells. Part 1: a new theoretical procedure and comparison with other methodologies

    Science.gov (United States)

    Rangel-Kuoppa, Victor-Tapio; Albor-Aguilera, María-de-Lourdes; Hérnandez-Vásquez, César; Flores-Márquez, José-Manuel; González-Trujillo, Miguel-Ángel; Contreras-Puente, Gerardo-Silverio

    2018-04-01

    A new proposal for the extraction of the shunt resistance (R sh ) and saturation current (I sat ) of a current-voltage (I-V) measurement of a solar cell, within the one-diode model, is given. First, the Cheung method is extended to obtain the series resistance (R s ), the ideality factor (n) and an upper limit for I sat . In this article which is Part 1 of two parts, two procedures are proposed to obtain fitting values for R sh and I sat within some voltage range. These two procedures are used in two simulated I-V curves (one in darkness and the other one under illumination) to recover the known solar cell parameters R sh , R s , n, I sat and the light current I lig and test its accuracy. The method is compared with two different common parameter extraction methods. These three procedures are used and compared in Part 2 in the I-V curves of CdS-CdTe and CIGS-CdS solar cells.

  13. Effect of oxide insertion layer on resistance switching properties of copper phthalocyanine

    Science.gov (United States)

    Joshi, Nikhil G.; Pandya, Nirav C.; Joshi, U. S.

    2013-02-01

    Organic memory device showing resistance switching properties is a next-generation of the electrical memory unit. We have investigated the bistable resistance switching in current-voltage (I-V) characteristics of organic diode based on copper phthalocyanine (CuPc) film sandwiched between aluminum (Al) electrodes. Pronounced hysteresis in the I-V curves revealed a resistance switching with on-off ratio of the order of 85%. In order to control the charge injection in the CuPc, nanoscale indium oxide buffer layer was inserted to form Al/CuPc/In2O3/Al device. Analysis of I-V measurements revealed space charge limited switching conduction at the Al/CuPc interface. The traps in the organic layer and charge blocking by oxide insertion layer have been used to explain the absence of resistance switching in the oxide buffer layered memory device cell. Present study offer potential applications for CuPc organic semiconductor in low power non volatile resistive switching memory and logic circuits.

  14. Effect of defect creation and migration on hump characteristics of a-InGaZnO thin film transistors under long-term drain bias stress with light illumination

    Science.gov (United States)

    Cho, Yong-Jung; Kim, Woo-Sic; Lee, Yeol-Hyeong; Park, Jeong Ki; Kim, Geon Tae; Kim, Ohyun

    2018-06-01

    We investigated the mechanism of formation of the hump that occurs in the current-voltage I-V characteristics of amorphous InGaZnO (a-IGZO) thin film transistors (TFTs) that are exposed to long-term drain bias stress under illumination. Transfer characteristics showed two-stage degradation under the stress. At the beginning of the stress, the I-V characteristics shifted in the negative direction with a degradation of subthreshold slope, but the hump phenomenon developed over time in the I-V characteristics. The development of the hump was related to creation of defects, especially ionized oxygen vacancies which act as shallow donor-like states near the conduction-band minimum in a-IGZO. To further investigate the hump phenomenon we measured a capacitance-voltage C-V curve and performed two-dimensional device simulation. Stretched-out C-V for the gate-to-drain capacitance and simulated electric field distribution which exhibited large electric field near the drain side of TFT indicated that VO2+ were generated near the drain side of TFT, but the hump was not induced when VO2+ only existed near the drain side. Therefore, the degradation behavior under DBITS occurred because VO2+ were created near the drain side, then were migrated to the source side of the TFT.

  15. Conductivity of Langmuir-Blodgett films of a disk-shaped liquid-crystalline molecule-DNA complex studied by current-sensing atomic force microscopy

    Science.gov (United States)

    Nayak, Alpana; Suresh, K. A.

    2008-08-01

    We have studied the electrical conductivity in monolayer films of an ionic disk-shaped liquid-crystal molecule, pyridinium tethered with hexaalkoxytriphenylene (PyTp), and its complex with DNA by current-sensing atomic force microscopy (CS-AFM). The pure PyTp and PyTp-DNA complex monolayer films were first formed at the air-water interface and then transferred onto conducting substrates by the Langmuir-Blodgett (LB) technique to study the nanoscale electron transport through these films. The conductive tip of CS-AFM, the LB film, and the metal substrate form a nanoscopic metal-LB film-metal (M-LB-M) junction. We have measured the current-voltage (I-V) characteristics for the M-LB-M junction using CS-AFM and have analyzed the data quantitatively. We find that the I-V curves fit well to the Fowler-Nordheim (FN) model, suggesting electron tunneling to be a possible mechanism for electron transport in our system. Further, analysis of the I-V curves based on the FN model yields the barrier heights of PyTp-DNA complex and pure PyTp films. Electron transport studies of films of ionic disk-shaped liquid-crystal molecules and their complex with DNA are important from the point of view of their applications in organic electronics.

  16. Evaluation of treatment effects for high-performance dye-sensitized solar cells using equivalent circuit analysis

    International Nuclear Information System (INIS)

    Murayama, Masaki; Mori, Tatsuo

    2006-01-01

    Equivalent circuit analysis using a one-diode model was carried out as a simpler, more convenient method to evaluate the electric mechanism and to employ effective treatment of a dye-sensitized solar cell (DSC). Cells treated using acetic acid or 4,t-butylpyridine were measured under irradiation (0.1 W/m 2 , AM 1.5) to obtain current-voltage (I-V) curves. Cell performance and equivalent circuit parameters were calculated from the I-V curves. Evaluation based on residual factors was useful for better fitting of the equivalent circuit to the I-V curve. The diode factor value was often over two for high-performance DSCs. Acetic acid treatment was effective to increase the short-circuit current by decreasing the series resistance of cells. In contrast, 4,t-butylpyridine was effective to increase open-circuit voltage by increasing the cell shunt resistance. Previous explanations considered that acetic acid worked to decrease the internal resistance of the TiO 2 layer and butylpyridine worked to lower the back-electron-transfer from the TiO 2 to the electrolyte

  17. Study of System Pressure Dependence on n-TiO2/p-Si Hetrostructure for Photovoltaic Applications

    Directory of Open Access Journals (Sweden)

    S. Ramezani Sani

    2015-01-01

    Full Text Available This study reports the fabrication of n-TiO2/p-Si hetrojunction by deposition of TiO2nanowires on p-Si substrate. The effect of system pressure and the current-voltage (I-V characteristics of n-TiO2/p-si hetrojunction were studied. The morphology of the samples was investigated by Field Emission Scanning Electron Microscopy (FESEM which confirms formation of TiO2 nanowires that their diameters increase with increasing the pressure of system. The I-V characteristics were measured to investigate the hetrojunction effects of under forward and reverse biases at different system pressure by sweeping in the voltage from 0 to +6 V, then to -6 V, and finally reaching 0 V. TiO2/Si diodes   in the system pressure 60 mbar and 30 mbar indicated that a p-n junction formed in the n-TiO2/p-Si hetrojunction. But as the system pressure increased to 1000 mbar, the I-V characteristics became inversed. This treatment can be scribed by the change of the energy band structure of TiO2.

  18. Electrical characteristics of schottky barriers on 4H-SiC: The effects of barrier height nonuniformity

    Science.gov (United States)

    Skromme, B. J.; Luckowski, E.; Moore, K.; Bhatnagar, M.; Weitzel, C. E.; Gehoski, T.; Ganser, D.

    2000-03-01

    Electrical properties, including current-voltage (I-V) and capacitance-voltage (C-V) characteristics, have been measured on a large number of Ti, Ni, and Pt-based Schottky barrier diodes on 4H-SiC epilayers. Various nonideal behaviors are frequently observed, including ideality factors greater than one, anomalously low I-V barrier heights, and excess leakage currents at low forward bias and in reverse bias. The nonidealities are highly nonuniform across individual wafers and from wafer to wafer. We find a pronounced linear correlation between I-V barrier height and ideality factor for each metal, while C-V barrier heights remain constant. Electron beam induced current (EBIC) imaging strongly suggests that the nonidealities result from localized low barrier height patches. These patches are related to discrete crystal defects, which become visible as recombination centers in the EBIC images. Alternative explanations involving generation-recombination current, uniform interfacial layers, and effects related to the periphery are ruled out.

  19. Quantum measurement

    CERN Document Server

    Busch, Paul; Pellonpää, Juha-Pekka; Ylinen, Kari

    2016-01-01

    This is a book about the Hilbert space formulation of quantum mechanics and its measurement theory. It contains a synopsis of what became of the Mathematical Foundations of Quantum Mechanics since von Neumann’s classic treatise with this title. Fundamental non-classical features of quantum mechanics—indeterminacy and incompatibility of observables, unavoidable measurement disturbance, entanglement, nonlocality—are explicated and analysed using the tools of operational quantum theory. The book is divided into four parts: 1. Mathematics provides a systematic exposition of the Hilbert space and operator theoretic tools and relevant measure and integration theory leading to the Naimark and Stinespring dilation theorems; 2. Elements develops the basic concepts of quantum mechanics and measurement theory with a focus on the notion of approximate joint measurability; 3. Realisations offers in-depth studies of the fundamental observables of quantum mechanics and some of their measurement implementations; and 4....

  20. A nanogenerator as a self-powered sensor for measuring the vibration spectrum of a drum membrane

    Science.gov (United States)

    Yu, Aifang; Zhao, Yong; Jiang, Peng; Wang, Zhong Lin

    2013-02-01

    A nanogenerator (NG) is a device that converts vibration energy into electricity. Here, a flexible, small size and lightweight NG is successfully demonstrated as an active sensor for detecting the vibration spectrum of a drum membrane without the use of an external power source. The output current/voltage signal of the NG is a direct measure of the strain of the local vibrating drum membrane that contains rich informational content, such as, notably, the vibration frequency, vibration speed and vibration amplitude. In comparison to the laser vibrometer, which is excessively complex and expensive, this kind of small and low cost sensor based on an NG is also capable of detecting the local vibration frequency of a drum membrane accurately. A spatial arrangement of the NGs on the membrane can provide position-dependent vibration information on the surface. The measured frequency spectrum can be understood on the basis of the theoretically calculated vibration modes. This work expands the application of NGs and reveals the potential for developing sound wave detection, environmental/infrastructure monitoring and many more applications.

  1. Measurement Uncertainty

    Science.gov (United States)

    Koch, Michael

    Measurement uncertainty is one of the key issues in quality assurance. It became increasingly important for analytical chemistry laboratories with the accreditation to ISO/IEC 17025. The uncertainty of a measurement is the most important criterion for the decision whether a measurement result is fit for purpose. It also delivers help for the decision whether a specification limit is exceeded or not. Estimation of measurement uncertainty often is not trivial. Several strategies have been developed for this purpose that will shortly be described in this chapter. In addition the different possibilities to take into account the uncertainty in compliance assessment are explained.

  2. Dispersion Free Doped and Undoped AlGaN/GaN HEMTs on Sapphire and SiC Substrates

    NARCIS (Netherlands)

    Kraemer, M.C.J.C.M.; Jacobs, B.; Kwaspen, J.J.M.; Suijker, E.M.; Hek, A.P. de; Karouta, F.; Kaufmann, L.M.F.; Hoskens, R.C.P.

    2004-01-01

    We present dispersion free pulsed current voltage (I-V) and radio frequency (RF) power results of undoped and doped AlGaN/GaN HEMTs on sapphire and SiC substrates. The most significant processing step leading to these results is the application of a reactive ion etching (RIE) argon (Ar) plasma

  3. Charge Transport and Photocurrent Generation Characteristics in Dye Solar Cells Containing Thermally Degraded N719 Dye Molecules

    DEFF Research Database (Denmark)

    Andersen, A. R.; Halme, J.; Lund, T.

    2011-01-01

    product (N719-TBP) on the performance parameters of the cells. Two types of dyed solar cells, based on either N719 or N719-TBP, have been characterized employing standard current-voltage (I-V) performance test, UV-vis optical spectroscopy, incident photon to current efficiency (IPCE), and electrochemical...

  4. Subharmonic energy-gap structure and heating effects in superconducting niobium point contacts

    DEFF Research Database (Denmark)

    Flensberg, K.; Hansen, Jørn Bindslev

    1989-01-01

    We present experimental data of the temperature-dependent subharmonic energy-gap structure (SGS) in the current-voltage (I-V) curves of superconducting niobium point contacts. The observed SGS is modified by heating effects. We construct a model of the quasiparticle conductance of metallic...

  5. Influence of the structural and compositional properties of PECVD silicon nitride layers on the passivation of AIGaN/GaN HEMTs

    NARCIS (Netherlands)

    Karouta, F.; Krämer, M.C.J.C.M.; Kwaspen, J.J.M.; Grzegorczyk, A.; Hageman, P.R.; Hoex, B.; Kessels, W.M.M.; Klootwijk, J.H.; Timmering, E.C.; Smit, M.K.; Wang, J.; Shiojima, K.

    2008-01-01

    We have investigated the influence of the structural and compositional properties of silicon nitride layers on the passivation of AlGaN/GaN HEMTs grown on sapphire substrates by assessing their continuous wave (CW) and pulsed current-voltage (I-V) characteristics. We have looked at the effect of

  6. Electron heating by photon-assisted tunneling in niobium terahertz mixers with integrated niobium titanium nitride striplines

    NARCIS (Netherlands)

    Leone, B; Gao, [No Value; Klapwijk, TM; Jackson, BD; Laauwen, WM; de Lange, G

    2001-01-01

    We describe the gap voltage depression and current-voltage (I-V) characteristics in pumped niobium superconductor-insulator-superconductor junction with niobium titanium nitride tuning stripline by introducing an electron heating power contribution resulting from the photon-assisted tunneling

  7. Local charge transport properties of hydrazine reduced monolayer graphene oxide sheets prepared under pressure condition

    DEFF Research Database (Denmark)

    Ryuzaki, Sou; Meyer, Jakob Abild Stengaard; Petersen, Søren Vermehren

    2014-01-01

    Charge transport properties of chemically reduced graphene oxide (RGO) sheets prepared by treatment with hydrazine were examined using conductive atomic force microscopy. The current-voltage (I-V) characteristics of monolayer RGO sheets prepared under atmospheric pressure followed an exponentially...

  8. Dedicated Tool for Irradiation and Electrical Measurement of Large Surface Samples on the Beamline of a 2.5 Mev Pelletron Electron Accelerator: Application to Solar Cells

    OpenAIRE

    Lefèvre Jérémie; Le Houedec Patrice; Losco Jérôme; Cavani Olivier; Boizot Bruno

    2017-01-01

    We designed a tool allowing irradiation of large samples over a surface of A5 size dimension by means of a 2.5 MeV Pelletron electron accelerator. in situ electrical measurements (I-V, conductivity, etc.) can also be performed, in the dark or under illumination, to study radiation effects in materials. Irradiations and electrical measurements are achievable over a temperature range from 100 K to 300 K. The setup was initially developed to test real-size triple junction solar cells at low t...

  9. Effect of annealing temperature on the electrical properties of Au/Ta{sub 2}O{sub 5}/n-GaN metal-insulator-semiconductor (MIS) structure

    Energy Technology Data Exchange (ETDEWEB)

    Prasanna Lakshmi, B.; Rajagopal Reddy, V.; Janardhanam, V. [Sri Venkateswara University, Department of Physics, Tirupati (India); Siva Pratap Reddy, M.; Lee, Jung-Hee [Kyungpook National University, School of Electrical Engineering and Computer Science, Daegu (Korea, Republic of)

    2013-11-15

    We report on the effect of an annealing temperature on the electrical properties of Au/Ta{sub 2}O{sub 5}/n-GaN metal-insulator-semiconductor (MIS) structure by current-voltage (I-V) and capacitance-voltage (C-V) measurements. The measured Schottky barrier height ({Phi} {sub bo}) and ideality factor n values of the as-deposited Au/Ta{sub 2}O{sub 5}/n-GaN MIS structure are 0.93 eV (I-V) and 1.19. The barrier height (BH) increases to 1.03 eV and ideality factor decreases to 1.13 upon annealing at 500 {sup circle} C for 1 min under nitrogen ambient. When the contact is annealed at 600 {sup circle} C, the barrier height decreases and the ideality factor increases to 0.99 eV and 1.15. The barrier heights obtained from the C-V measurements are higher than those obtained from I-V measurements, and this indicates the existence of spatial inhomogeneity at the interface. Cheung's functions are also used to calculate the barrier height ({Phi} {sub bo}), ideality factor (n), and series resistance (R{sub s}) of the Au/Ta{sub 2}O{sub 5}/n-GaN MIS structure. Investigations reveal that the Schottky emission is the dominant mechanism and the Poole-Frenkel emission occurs only in the high voltage region. The energy distribution of interface states is determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. It is observed that the density value of interface states for the annealed samples with interfacial layer is lower than that of the density value of interface states of the as-deposited sample. (orig.)

  10. Measuring Colour

    CERN Document Server

    Hunt, R W G

    2011-01-01

    The classic authority on colour measurement now fully revised and updated with the latest CIE recommendations The measurement of colour is of major importance in many commercial applications, such as the textile, paint, and foodstuff industries; as well as having a significant role in the lighting, paper, printing, cosmetic, plastics, glass, chemical, photographic, television, transport, and communication industries. Building upon the success of earlier editions, the 4th edition of Measuring Colour has been updated throughout with new chapters on colour rendering by light sources; colorimetry

  11. Mechanical measurements

    CERN Document Server

    Venkateshan, S P

    2015-01-01

    The first edition of this book was co-published by Ane Books India, and CRC Press in 2008. This second edition is an enlarged version of the web course developed by the author at IIT Madras, and also a modified and augmented version of the earlier book.  Major additions/modifications presented are in the treatment of errors in measurement, temperature measurement, measurement of thermo-physical properties, and data manipulation. Many new worked examples have been introduced in this new and updated second edition. 

  12. Flow-rate measurements in closed-conduits by tracer techniques

    International Nuclear Information System (INIS)

    Lund Plantat, C.

    1982-01-01

    This paper presents the study of the precision obtained measuring flow-rates in closed-conduits by tracer techniques. The flow-rates analyzed were in the range of 10 to 20 l/s and Reynolds numbers from 10 5 to 2 x 10 5 . Tracer used were fluoresceine and In-113 m; and the measurements were performed with the dilution method (punctual and continuous injection) and the Allen method. Precisions for the method of punctual and continuous injections were 6.25% and 9.45% for fluoresceine and 9.3% and 3% for In-113, respectively. For Allen method with In-113 m a precision of 5% was obtained; probably this value was affected by the short distance between detectors. In all cases the error corresponds with the expected value except in one measurement at a 68.3% confidence level. (I.V.)

  13. Conductive Au nanowires regulated by silk fibroin nanofibers

    Science.gov (United States)

    Dong, Bo-Ju; Lu, Qiang

    2014-03-01

    Conductive Au-biopolymer composites have promising applications in tissue engineering such as nerve tissue regeneration. In this study, silk fibroin nanofibers were formed in aqueous solution by regulating silk self-assembly process and then used as template for Au nanowire fabrication. We performed the synthesis of Au seeds by repeating the seeding cycles for several times in order to increase the density of Au seeds on the nanofibers. After electroless plating, densely decorated Au seeds grew into irregularly shaped particles following silk nanofiber to fill the gaps between particles and finally form uniform continuous nanowires. The conductive property of the Au-silk fibroin nanowires was studied with current-voltage ( I-V) measurement. A typical ohmic behavior was observed, which highlighted their potential applications in nerve tissue regeneration.

  14. Interdigitated electrode (IDE) for porcine detection based on titanium dioxide (TiO_2) thin films

    International Nuclear Information System (INIS)

    Nordin, N.; Azizah, N.; Hashim, U.

    2016-01-01

    Interdigited Electrode (IDE) porcine detection can be accomplished to authenticate the halal issue that has been a concern to Muslim not only in Malaysia but all around the world. The method used is photolithography that used the p-type photoresist on the spin coater with 2500 rpm. Bare IDEs device is deposited with Titanium Dioxide (TiO_2) to improve the performance of the device. The result indicates that current-voltage (I-V) measurement of porcine probe line slightly above porcine target due to negative charges repelled each other. The IDE device can detect the porcine presence in food as lowest as 1.0 µM. Better performance of the device can be achieved with the replacement of gold deposited to trigger more sensitivity of the device.

  15. Interdigitated electrode (IDE) for porcine detection based on titanium dioxide (TiO2) thin films

    Science.gov (United States)

    Nordin, N.; Hashim, U.; Azizah, N.

    2016-07-01

    Interdigited Electrode (IDE) porcine detection can be accomplished to authenticate the halal issue that has been a concern to Muslim not only in Malaysia but all around the world. The method used is photolithography that used the p-type photoresist on the spin coater with 2500 rpm. Bare IDEs device is deposited with Titanium Dioxide (TiO2) to improve the performance of the device. The result indicates that current-voltage (I-V) measurement of porcine probe line slightly above porcine target due to negative charges repelled each other. The IDE device can detect the porcine presence in food as lowest as 1.0 µM. Better performance of the device can be achieved with the replacement of gold deposited to trigger more sensitivity of the device.

  16. Interdigitated electrode (IDE) for porcine detection based on titanium dioxide (TiO{sub 2}) thin films

    Energy Technology Data Exchange (ETDEWEB)

    Nordin, N.; Azizah, N. [Institute of Electronic Engineering (INEE), Universiti Malaysia Perlis, 01000 Kangar Perlis (Malaysia); Hashim, U., E-mail: uda@unimap.edu.my [Institute of Electronic Engineering (INEE), Universiti Malaysia Perlis, 01000 Kangar Perlis (Malaysia); School of Microelctronic Engineering, Universiti Malaysia Perlis, 01000 Kangar Perlis (Malaysia)

    2016-07-06

    Interdigited Electrode (IDE) porcine detection can be accomplished to authenticate the halal issue that has been a concern to Muslim not only in Malaysia but all around the world. The method used is photolithography that used the p-type photoresist on the spin coater with 2500 rpm. Bare IDEs device is deposited with Titanium Dioxide (TiO{sub 2}) to improve the performance of the device. The result indicates that current-voltage (I-V) measurement of porcine probe line slightly above porcine target due to negative charges repelled each other. The IDE device can detect the porcine presence in food as lowest as 1.0 µM. Better performance of the device can be achieved with the replacement of gold deposited to trigger more sensitivity of the device.

  17. Surface Passivation of CdZnTe Detector by Hydrogen Peroxide Solution Etching

    Science.gov (United States)

    Hayes, M.; Chen, H.; Chattopadhyay, K.; Burger, A.; James, R. B.

    1998-01-01

    The spectral resolution of room temperature nuclear radiation detectors such as CdZnTe is usually limited by the presence of conducting surface species that increase the surface leakage current. Studies have shown that the leakage current can be reduced by proper surface preparation. In this study, we try to optimize the performance of CdZnTe detector by etching the detector with hydrogen peroxide solution as function of concentration and etching time. The passivation effect that hydrogen peroxide introduces have been investigated by current-voltage (I-V) measurement on both parallel strips and metal-semiconductor-metal configurations. The improvements on the spectral response of Fe-55 and 241Am due to hydrogen peroxide treatment are presented and discussed.

  18. Synthesis of novel carbazole derived substances using some organoboron compounds by palladium catalyzed and investigation of its semiconductor device characteristics

    Science.gov (United States)

    Gorgun, Kamuran; Caglar, Yasemin

    2018-04-01

    Carbazole compounds in particular represent one of the most intensely used and studied class of semiconducting materials. In this study, considering the information given in the literature the Ullman and Suzuki-Miyaura coupling reaction were carried out using carbazole, 1,4-dibromobenzene and pyrene-1-boronic acid. The synthesized carbazole derivatives are characterized by 1H NMR and elemental analysis. The spectroscopic and thermal properties of the synthesized novel carbazole derivative 9-(4-(pyren-4-yl)phenyl)-9H-carbazole (Cz-py) were investigated. And also, the n-Si/p-Cz:py heterojunction diode was fabricated. The electrical properties of this diode were characterized by current-voltage (I-V) and capacitance-voltage (C-V) measurements.

  19. Carrier Transport of Silver Nanowire Contact to p-GaN and its Influence on Leakage Current of LEDs

    Science.gov (United States)

    Oh, Munsik; Kang, Jae-Wook; Kim, Hyunsoo

    2018-03-01

    The authors investigated the silver nanowires (AgNWs) contact formed on p-GaN. Transmission line model applied to the AgNWs contact to p-GaN produced near ohmic contact with a specific contact resistance (ρ sc) of 10-1˜10-4 Ω·cm2. Noticeably, the contact resistance had a strong bias-voltage (or current-density) dependence associated with a local joule heating effect. Current-voltage-temperature (I-V-T) measurement revealed a strong temperature dependence with respect to ρ sc, indicating that the temperature played a key role of an enhanced carrier transport. The local joule heating at AgNW/GaN interface, however, resulted in a generation of leakage current of light-emitting diodes (LEDs) caused by degradation of AgNW contact.

  20. A direct investigation of photocharge transfer across monomolecular layer between C{sub 60} and CdS quantum dots by photoassisted conductive atomic force microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Xiaohong; Liu, He; Zhang, Xingtang; Cheng, Gang; Wang, Shujie; Du, Zuliang, E-mail: zld@henu.edu.cn [Key Laboratory for Special Functional Materials, Collaborative Innovation Center of Nano Functional Materials and Applications, Henan University, Kaifeng, 475004, PR. China (China)

    2016-04-15

    The composite assembly of C{sub 60} and CdS Quantum Dots (QDs) on ITO substrate was prepared by Langmuir-Blodgett (LB) technique using arachic acid (AA), stearic acid (SA) and octadecanyl amine (OA) as additives. Photoassisted conductive atomic force microscopy was used to make point contact current-voltage (I-V) measurements on both the CdS QDs and the composite assembly of C{sub 60}/CdS. The result make it clear that the CdS, C{sub 60}/CdS assemblies deposited on ITO substrate showed linear characteristics and the current increased largely under illumination comparing with that in the dark. The coherent, nonresonant tunneling mechanism was used to explain the current occurrence. It is considered that the photoinduced carriers CdS QDs tunneled through alkyl chains increased the current rapidly.

  1. Effect of growth time to the properties of Al-doped ZnO nanorod arrays

    Science.gov (United States)

    Ismail, A. S.; Mamat, M. H.; Malek, M. F.; Saidi, S. A.; Yusoff, M. M.; Mohamed, R.; Sin, N. D. Md; Suriani, A. B.; Rusop, M.

    2018-05-01

    Aluminum (Al)-doped zinc oxide (ZnO) nanorod array films were successfully deposited at different growth time on zinc oxide (ZnO) seed layer coated glass substrate using sol-gel immersion method. The morphology images of the films showed that the thicknesses of the films were increased parallel with the increment of growth period. The surface topology of the films displayed an increment of roughness as the growth period increased. Optical properties of the samples exposed that the percentage of transmittances reduced at higher growth time. Besides, the Urbach energy of the films slightly increased as the immersion time increased. The current-voltage (I-V) measurement indicated that the resistance increased as the immersion time increased owing to the appearance of intrinsic layer on top of the nanorods.

  2. A Room-temperature Hydrogen Gas Sensor Using Palladium-decorated Single-Walled Carbon Nanotube/Si Heterojunction

    Directory of Open Access Journals (Sweden)

    Yong Gang DU

    2016-05-01

    Full Text Available We report a room-temperature (RT hydrogen gas (H2 sensor based on palladium-decorated single-walled carbon nanotube/Si (Pd-SWNTs/Si heterojunction. The current-voltage (I-V curves of the Pd-SWNTs/Si heterojunction in different concentrations of H2 were measured. The experimental results reveal that the Pd-SWNTs/Si heterojunction exhibits high H2 response. After exposure to 0.02 %, 0.05 %, and 0.1 % H2 for 10 min, the resistance of the heterojunction increases dramatically. The response is 122 %, 269 % and 457 %, respectively. A simple interfacial theory is used to understand the gas sensitivity results. This approach is a step toward future CNTs-based gas sensors for practical application.DOI: http://dx.doi.org/10.5755/j01.ms.22.2.12925

  3. Indium-oxide nanoparticles for RRAM devices compatible with CMOS back-end-off-line

    Science.gov (United States)

    León Pérez, Edgar A. A.; Guenery, Pierre-Vincent; Abouzaid, Oumaïma; Ayadi, Khaled; Brottet, Solène; Moeyaert, Jérémy; Labau, Sébastien; Baron, Thierry; Blanchard, Nicholas; Baboux, Nicolas; Militaru, Liviu; Souifi, Abdelkader

    2018-05-01

    We report on the fabrication and characterization of Resistive Random Access Memory (RRAM) devices based on nanoparticles in MIM structures. Our approach is based on the use of indium oxide (In2O3) nanoparticles embedded in a dielectric matrix using CMOS-full-compatible fabrication processes in view of back-end-off-line integration for non-volatile memory (NVM) applications. A bipolar switching behavior has been observed using current-voltage measurements (I-V) for all devices. Very high ION/IOFF ratios have been obtained up to 108. Our results provide insights for further integration of In2O3 nanoparticles-based devices for NVM applications. He is currently a Postdoctoral Researcher in the Institute of Nanotechnologies of Lyon (INL), INSA de Lyon, France, in the Electronics Department. His current research include indium oxide nanoparticles for non-volatile memory applications, and the integrations of these devices in CMOS BEOL.

  4. Enhancement in photovoltaic properties of silicon solar cells by surface plasmon effect of palladium nanoparticles

    Science.gov (United States)

    Atyaoui, Malek; Atyaoui, Atef; Khalifa, Marwen; Elyagoubi, Jalel; Dimassi, Wissem; Ezzaouia, Hatem

    2016-04-01

    This work presents the surface Plasmon effect of Palladium nanoparticles (Pd NPs) on the photovoltaic properties of silicon solar cells. Pd NPs were deposited on the p-type silicon base of the n+/p junction using a chemical deposition method in an aqueous solution containing Palladium (II) Nitrate (PdNO3)2 and Ammonium Hydroxide (NH4OH) followed by a thermal treatment at 500 °C under nitrogen atmosphere. Chemical composition and surface morphology of the treated silicon base were examined by energy dispersive X-ray (EDX) spectroscopy, scanning electronic microscopy (SEM) and Atomic Force Microscopy (AFM). The effect of the deposited Pd NPs on the electrical properties was evaluated by the internal quantum efficiency (IQE) and current-voltage (I-V) measurements. The results indicate that the formation of the Pd NPs is accompanied by an enhanced light absorption and improved photovoltaic parameters.

  5. Influence of temperature and light intensity on Ru(II) complex based organic-inorganic device

    International Nuclear Information System (INIS)

    Asubay, Sezai; Durap, Feyyaz; Aydemir, Murat; Baysal, Akin; Ocak, Yusuf Selim; Tombak, Ahmet

    2016-01-01

    An organic-inorganic junction was fabricated by forming [Ru(Cy_2PNHCH_2-C_4H_3O)(η"6-p-cymene)Cl_2] complex thin film using spin coating technique on n-Si and evaporating Au metal on the film. It was seen that the structure had perfect rectification property. Current-voltage (I-V) measurements were carried out in dark and under various illumination conditions (between 50-100 mW/cm"2) and with the temperature range from 303 to 380 K. The structure showed unusually forward and reverse bias temperature and light sensing behaviors. It was seen that the current both in forward and reverse bias increased with the increase in light intensity and temperature.

  6. Temperature dependent electrical characteristics of an organic-inorganic heterojunction obtained from a novel organometal Mn complex

    International Nuclear Information System (INIS)

    Ocak, Y.S.; Ebeoglu, M.A.; Topal, G.; Kilicoglu, T.

    2010-01-01

    This study includes synthesizing a Mn hexaamide (MnHA) organometal compound (C 27 H 21 N 9 O 6 MnCl 2 ).(1/2H 2 O), fabrication of MnHA/n-Si organic-inorganic heterojunction and analysis of conduction mechanism of the device over the room temperature. After synthesizing the molecule, the structure of the compound was determined using spectroscopic methods. The Sn/MnHA/n-Si structure was constructed by forming a thin MnHA layer on n-Si inorganic semiconductor and evaporating Sn metal on organic complex. The structure has shown good rectifying behavior and obeys the thermionic emission theory. The current-voltage (I-V) characteristics of the diode have been measured at temperatures ranging from 300 to 380 K at 10 K intervals to determine the temperature dependent electrical characteristics of the device.

  7. A Fabrication Technique for Nano-gap Electrodes by Atomic Force Microscopy Nano lithography

    International Nuclear Information System (INIS)

    Jalal Rouhi; Shahrom Mahmud; Hutagalung, S.D.; Kakooei, S.

    2011-01-01

    A simple technique is introduced for fabrication of nano-gap electrodes by using nano-oxidation atomic force microscopy (AFM) lithography with a Cr/ Pt coated silicon tip. AFM local anodic oxidation was performed on silicon-on-insulator (SOI) surfaces by optimization of desired conditions to control process in contact mode. Silicon electrodes with gaps of sub 31 nm were fabricated by nano-oxidation method. This technique which is simple, controllable, inexpensive and fast is capable of fabricating nano-gap structures. The current-voltage measurements (I-V) of the electrodes demonstrated very good insulating characteristics. The results show that silicon electrodes have a great potential for fabrication of single molecule transistors (SMT), single electron transistors (SET) and the other nano electronic devices. (author)

  8. Enhanced magnetoresistance in graphene spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Iqbal, Muhammad Zahir, E-mail: zahir.upc@gmail.com [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Hussain, Ghulam [Faculty of Engineering Sciences, GIK Institute of Engineering Sciences and Technology, Topi 23640, Khyber Pakhtunkhwa (Pakistan); Siddique, Salma [Department of Bioscience & Biotechnology, Sejong University, Seoul 143-747 (Korea, Republic of); Iqbal, Muhammad Waqas [Department of Physics, Riphah Institute of Computing and Applied Sciences (RICAS), Riphah International University, Lahore (Pakistan)

    2017-05-01

    Graphene has been explored as a promising candidate for spintronics due to its atomically flat structure and novel properties. Here we fabricate two spin valve junctions, one from directly grown graphene on Ni electrode (DG) and other from transferred graphene (TG). The magnetoresistance (MR) ratio for DG device is found to be higher than TG device i.e. ~0.73% and 0.14%, respectively. Also the spin polarization of Ni electrode is determined to be 6.03% at room temperature in case of DG device, however it reduces to 2.1% for TG device. From this analysis, we infer how environmental exposure of the sample degrades the spin properties of the magnetic junctions. Moreover, the transport measurements reveal linear behavior for current-voltage (I-V) characteristics, indicating ohmic behavior of the junctions. Our findings unveil the efficiency of direct growth of graphene for spin filtering mechanism in spin valve devices.

  9. New method of silicon photovoltaic panel fault detection using impedance spectroscopy

    DEFF Research Database (Denmark)

    Symonowicz, Joanna Karolina; Riedel, Nicholas; Thorsteinsson, Sune

    2017-01-01

    The aim of our project is to develop a new method for photovoltaic (PV) panel fault detection based on analysing its impedance spectra (IS). Although this technique was successful in assessing the state of degradation of fuel cells and batteries [1, 2], it has never been applied to PV cells...... on a wide scale. In this paper, we show that, unlike current-voltage (I-V) tests, the IS method is capable of early detection of changes in PV panel parameters due to microcracks and potential-induced degradation (PID). Although our measurements are only successful under dark conditions, the results...... are similar for both laboratory environment and for outdoor tests in various weather conditions. A fully developed IS technique, accounting for all kinds of most common PV panel degradation types, would surpass the existing PV fault detection methods then it comes to cost and accuracy [3,4]....

  10. Negative differential resistance effect induced by metal ion implantation in SiO2 film for multilevel RRAM application

    Science.gov (United States)

    Wu, Facai; Si, Shuyao; Shi, Tuo; Zhao, Xiaolong; Liu, Qi; Liao, Lei; Lv, Hangbing; Long, Shibing; Liu, Ming

    2018-02-01

    Pt/SiO2:metal nanoparticles/Pt sandwich structure is fabricated with the method of metal ion (Ag) implantation. The device exhibits multilevel storage with appropriate R off/R on ratio, good endurance and retention properties. Based on transmission electron microscopy and energy dispersive spectrometer analysis, we confirm that Pt nanoparticles are spurted into SiO2 film from Pt bottom electrode by Ag implantation; during electroforming, the local electric field can be enhanced by these Pt nanoparticles, meanwhile the Ag nanoparticles constantly migrate toward the Pt nanoparticles. The implantation induced nanoparticles act as trap sites in the resistive switching layer and play critical roles in the multilevel storage, which is evidenced by the negative differential resistance effect in the current-voltage (I-V) measurements.

  11. Fabrication and characterization of n-AlGaAs/ GaAs Schottky diode for rectennas device application

    International Nuclear Information System (INIS)

    Norfarariyanti Parimon; Abdul Manaf Hashim; Farahiyah Mustafa

    2009-01-01

    Full text: Schottky diode was designed and fabricated on n-AlGaAs/GaAs high electron mobility transistor (HEMT) structure for rectennas device application. Rectennas is one of the most potential devices to form the wireless power supply which is really good at converting microwaves to DC. The processing steps used in the fabrication of Schottky diode were the conventional steps used in standard GaAs processing. Current?voltage (I-V) measurements showed that the device had rectifying properties with a barrier height of 0.5468 eV for Ni/Au metallization. The fabricated Schottky diode detected RF signals and the cut-off frequency up to 20 GHz was estimated in direct injection experiments. These preliminary results will provide a breakthrough for the direct integration with antenna towards realization of rectennas device application. (author)

  12. Power Conversion Efficiency of AlGaAs/GaAs Schottky Diode for Low-Power On-Chip Rectenna Device Application

    International Nuclear Information System (INIS)

    Mustafa, Farahiyah; Hashim, Abdul Manaf; Rahman, Shaharin Fadzli Abd; Osman, Mohd Nizam

    2011-01-01

    A Schottky diode has been designed and fabricated on n-AlGaAs/GaAs high-electron-mobility-transistor (HEMT) structure. Current-voltage (I-V) measurements show good device rectification with a Schottky barrier height of 0.4349 eV for Ni/Au metallization. The differences of Schottky barrier height from theoretical value are due to the fabrication process and smaller contact area. The RF signals up to 1 GHz are well rectified by the fabricated Schottky diodes and stable DC output voltage is obtained. Power conversion efficiency up to 50% is obtained at 1 GHz with series connection between diode and load. The fabricated the n-AlGaAs/GaAs Schottky diode provide conduit for breakthrough designs for ultra-low power on-chip rectenna device technology to be integrated in nanosystems.

  13. Fabrication and Characterization of n-AlGaAs/GaAs Schottky Diode for Rectenna Device Application

    Energy Technology Data Exchange (ETDEWEB)

    Parimon, Norfarariyanti; Mustafa, Farahiyah; Hashim, Abdul Manaf; Rahman, Shaharin Fadzli Abd; Rahman, Abdul Rahim Abdul [Material Innovations and Nanoelectronics Research Group, Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Osman, Mohd Nizam, E-mail: manaf@fke.utm.my [Telekom Research and Development, TM Innovation Centre, 63000 Cyberjaya (Malaysia)

    2011-02-15

    Schottky diode was designed and fabricated on n-AlGaAs/GaAs high electron mobility transistor (HEMT) structure for rectenna device application. Rectenna is one of the most potential devices to form the wireless power supply which is really good at converting microwaves to DC. The processing steps used in the fabrication of Schottky diode were the conventional steps used in standard GaAs processing. Current-voltage (I-V) measurements showed that the device had rectifying properties with a barrier height of 0.5468 eV for Ni/Au metallization. The fabricated Schottky diode detected RF signals and the cut-off frequency up to 20 GHz was estimated in direct injection experiments. These preliminary results will provide a breakthrough for the direct integration with antenna towards realization of rectenna device application.

  14. Electrical characterization of Au/ZnO/Si Schottky contact

    International Nuclear Information System (INIS)

    Asghar, M; Mahmood, K; Faisal, M; Hasan, M A

    2013-01-01

    In this study, temperature dependent current-voltage (I-V) and capacitance-voltage (C-V) measurements have been performed on Au/ZnO/Si Schottky barrier diode in the range 150 – 400K. The room temperature values for ideality factor and barrier height found to be 2.68 and 0.68 eV respectively. From the temperature dependence of I–V, the ideality factor was observed to decrease with increasing temperature and barrier height increased with increasing temperature. The observed barrier height trend was disagreeing with the negative temperature coefficient for semiconductor. A deep defect with activation energy 0.57 eV below the conduction band was observed using the saturation current plot and deep level transient spectroscopy.

  15. Electronic properties of junctions between aluminium and polyaniline doped with dodecylbenzene sulphonate

    International Nuclear Information System (INIS)

    Bantikassegn, W.

    1997-07-01

    Polyaniline (PANI) doped with dodecylbenzene sulphonate (DBS) anions forms a conducting organic sold. Aluminium contacts to PANI (DBS) polymer are studied using complex impedance spectroscopy and current-voltage characteristics measurements. The I-V characteristic is asymmetric and non-ohmic and shows rectification. The complex impedance spectra show two practically overlapping semi-circles which reveal the existence of two distinct regions at the metal/doped polymer interface. They are modelled by an equivalent circuit consisting of two parallel RC circuits in series representing a thin interfacial insulating (S') layer and a depletion (S) region. The device is therefore an MS'S type, where S' and S are the same chemical compounds in which the S' layer has very low doping content than the S layer. (author). 32 refs, 2 figs, 1 tab

  16. Analog front end circuit design of CSNS beam loss monitor system

    International Nuclear Information System (INIS)

    Xiao Shuai; Guo Xian; Tian Jianmin; Zeng Lei; Xu Taoguang; Fu Shinian

    2013-01-01

    The China Spallation Neutron Source (CSNS) beam loss monitor system uses gas ionization chamber to detect beam losses. The output signals from ionization chamber need to be processed in the analog front end circuit, which has been designed and developed independently. The way of transimpedance amplifier was used to achieve current-voltage (I-V) conversion measurement of signal with low repetition rate, low duty cycle and low amplitude. The analog front end circuit also realized rapid response to the larger beam loss in order to protect the safe operation of the accelerator equipment. The testing results show that the analog front end circuit meets the requirements of beam loss monitor system. (authors)

  17. Annealing temperature effect on electrical properties of MEH-PPV thin film via spin coating method

    Science.gov (United States)

    Azhar, N. E. A.; Shariffudin, S. S.; Alrokayan, Salman A. H.; Khan, Haseeb A.; Rusop, M.

    2018-05-01

    Organic semiconductor has been discovered in different application devices such as organic light emitting diodes (OLEDs). Poly [2-methoxy-5(2' -ethylhexyloxy)-1, 4-phenylenevinylene), MEH-PPV widely used in this device because its ability to produce a good optical quality films. The MEH-PPV was prepared on glass substrate by spin coating method. The thin film was investigated at different annealing temperatures. The scanning electron micrographs (SEM) revealed that sample annealed at 50°C showed uniformity and less aggregation on morphology polymer thin film. Optical properties showed the intensities of visible emission increased as temperatures increased. The current-voltage (I-V) measurement revealed that the temperature of 50°C showed high conductive and it is suitable for optoelectronic device.

  18. Effect of co-doping process on topography, optical and electrical properties of ZnO nanostructured

    Science.gov (United States)

    Mohamed, R.; Mamat, M. H.; Malek, M. F.; Ismail, A. S.; Yusoff, M. M.; Syamsir, S. A.; Khusaimi, Z.; Rusop, M.

    2018-05-01

    We investigated of Undoped ZnO and Magnesium (Mg)-Aluminium (Al) co-doped Zinc Oxide (MAZO) nanostructured films were prepared by sol gel spin coating technique. The surface topography was analyzed using Atomic Force Microscopy (AFM). Based on the AFM results, Root Mean Square (RMS) of MAZO films have rougher surface compared to pure ZnO films. The optical and electrical properties of thin film samples were characterized using Uv-Vis spectroscopy and two point probes, current-voltage (I-V) measurements. The transmittance spectra for both thin samples was above 80% in the visible wavelength. The MAZO film shows the highest conductivity compared to pure ZnO films. This result indicates that the improvement of carrier mobility throughout doping process and possibly contribute by extra ion charge.

  19. Electrical characteristics of ZnO nanorods reinforced polymer nanocomposite thin films

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharjee, Snigdha; Roy, Asim, E-mail: 28.asim@gmail.com [Department of Physics National Institute Technology Silchar Silchar-788010, Assam (India)

    2015-05-15

    ZnO nanorods have been prepared by simple chemical method, which is used to fabricate organic bistable devices (OBDs). OBDs are fabricated by incorporating different weight percent (wt %) of chemically synthesized Zinc Oxide (ZnO) nanorods into polymethylmethacrylate (PMMA). Current-voltage (I-V) measurements of the spin coated ZnO+PMMA nanocomopsite thin film on indium tin oxide (ITO) coated glass substrate showed current hysteresis behaviour, which is an indication of memory effect. The samples exhibit two distinct resistance states, ON and OFF states, characterised by relatively low and high resistance of the OBDs, respectively. It is also observed that with change in ZnO dopant concentration the value of ON/OFF current changes. Higher ON/OFF current ratio is desired for practical applications. Current conduction mechanism of the devices has been explained invoking various existing models, and it has been found that the trapped-charge-limited conduction mechanism was dominant in our samples.

  20. Charge-trapping effect of doped fluorescent dye on the electroluminescent processes and its performance in polymer light-emitting diodes

    Energy Technology Data Exchange (ETDEWEB)

    Ye Tengling; Chen Zhenyu; Chen Jiangshan [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China); Ma Dongge, E-mail: mdg1014@ciac.jl.cn [State Key Laboratory of Polymer Physics and Chemistry, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Graduate School of Chinese Academy of Sciences, Changchun 130022 (China)

    2010-11-15

    We have measured the temperature dependence of the steady-state current-voltage (I-V) characteristics and the transient electroluminescent (EL) characteristics in 4-(dicyanomethylene)-2-t-propyl-6-(1,1,7, 7-tetramethyljulolidyl-9-enyl)-4H-pyran (DCJTB) doped polyfluorene devices to study the charge-trapping effect of DCJTB fluorescent dye on luminescence processes and on device performance. Physical and chemical analyses prove that DCJTB molecules serve both as electron and hole traps, and the charge-trapping effect is more sensitive against the electrons than the holes at the low dopant concentration. This intrinsic characteristic causes the electron to be injected into the emitting layer first and then trapped in the bulk, producing a strong effect on device performance.