WorldWideScience

Sample records for current-voltage i-v measurements

  1. 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.

  2. 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.

  3. Variable Temperature Current-Voltage Measurements of CdTe Solar Cells

    Science.gov (United States)

    Smith, A. D.

    2000-03-01

    We have used a 2" x 2" Peltier heat pump chip powered with 24 V from a computer power supply to build a variable temperature stage for current voltage measurements of solar cells. A voltage divider was used to achieve several different set point temperatures from 25 oC to -24 oC. This system was used with a halogen lamp to study the electrical performance of polycrystalline thin-film solar cells fabricated in our group. These cells have the superstrate structure glass/SnO2:F/CdS/CdTe/metal.(1) The I-V characteristic shows evidence of a blocking back-diode which sets in below room temperature. This behavior will be related to the diffusion into the CdTe of the metals used for our back contact.(2) 1. M. Shao, A. Fischer, D. Grecu, U. Jayamaha, E. Bykov, G. Contreras-Puente, R.G. Bohn, and A.D. Compaan, Appl. Phys. Lett. 69, 3045-3047 (1996). 2. D. Grecu and A.D. Compaan, Appl. Phys. Lett. 75, 361-363 (1999).

  4. 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......-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...... for monitoring single or independent PV strings, and is based on evaluating the ratio of certain operation points on the string I-V curve. The second method is applicable to PV systems with identical strings, and is based on monitoring and inter-comparison of string I-V curve parameters. For PV systems with non...

  5. The PPTN-02 new-generation current-voltage transducers for measuring of photosignals

    Directory of Open Access Journals (Sweden)

    Butenko V. K.

    2008-02-01

    Full Text Available The measurement results of technical characteristics of new-generation current-voltage transducers which have low input resistance (<10 Оhm and providing ptotodiodes photocurrent measurement from 1·10-12 to 1·10-3 A are presented.

  6. Measurement system for determination of current-voltage characteristics of PV modules

    Science.gov (United States)

    Idzkowski, Adam; Walendziuk, Wojciech; Borawski, Mateusz; Sawicki, Aleksander

    2015-09-01

    The realization of a laboratory stand for testing photovoltaic panels is presented here. The project of the laboratory stand was designed in SolidWorks software. The aim of the project was to control the electrical parameters of a PV panel. For this purpose a meter that measures electrical parameters i.e. voltage, current and power, was realized. The meter was created with the use of LabJack DAQ device and LabVIEW software. The presented results of measurements were obtained in different conditions (variable distance from the source of light, variable tilt angle of the panel). Current voltage characteristics of photovoltaic panel were created and all parameters could be detected in different conditions. The standard uncertainties of sample voltage, current, power measurements were calculated. The paper also gives basic information about power characteristics and efficiency of a solar cell.

  7. Transient Response of Organo-Metal-Halide Solar Cells Analyzed by Time-Resolved Current-Voltage Measurements

    Directory of Open Access Journals (Sweden)

    M. Greyson Christoforo

    2015-11-01

    Full Text Available The determination of the power conversion efficiency of solar cells based on organo-metal-halides is subject to an ongoing debate. As solar cell devices may exhibit very slow transient response, current-voltage scans in different directions may not be congruent, which is an effect often referred to as hysteresis. We here discuss time-resolved current-voltage measurements as a means to evaluate appropriate delay times (voltage settling times to be used in current-voltage measurements of solar cells. Furthermore, this method allows the analysis of transient current response to extract time constants that can be used to compare characteristic differences between devices of varying architecture types, selective contacts and changes in devices due to storage or degradation conditions.

  8. Radio frequency current-voltage probe for impedance and power measurements in multi-frequency unmatched loads

    Science.gov (United States)

    Lafleur, T.; Delattre, P. A.; Booth, J. P.; Johnson, E. V.; Dine, S.

    2013-01-01

    A broad-band, inline current-voltage probe, with a characteristic impedance of 50 Ω, is presented for the measurement of voltage and current waveforms, impedance, and power in rf systems. The probe, which uses capacitive and inductive sensors to determine the voltage and current, respectively, can be used for the measurement of single or multi-frequency signals into both matched and unmatched loads, over a frequency range of about 1-100 MHz. The probe calibration and impedance/power measurement technique are described in detail, and the calibrated probe results are compared with those obtained from a vector network analyzer and other commercial power meters. Use of the probe is demonstrated with the measurement of power into an unmatched capacitively coupled plasma excited by multi-frequency tailored voltage waveforms.

  9. Radio frequency current-voltage probe for impedance and power measurements in multi-frequency unmatched loads.

    Science.gov (United States)

    Lafleur, T; Delattre, P A; Booth, J P; Johnson, E V; Dine, S

    2013-01-01

    A broad-band, inline current-voltage probe, with a characteristic impedance of 50 Ω, is presented for the measurement of voltage and current waveforms, impedance, and power in rf systems. The probe, which uses capacitive and inductive sensors to determine the voltage and current, respectively, can be used for the measurement of single or multi-frequency signals into both matched and unmatched loads, over a frequency range of about 1-100 MHz. The probe calibration and impedance/power measurement technique are described in detail, and the calibrated probe results are compared with those obtained from a vector network analyzer and other commercial power meters. Use of the probe is demonstrated with the measurement of power into an unmatched capacitively coupled plasma excited by multi-frequency tailored voltage waveforms.

  10. Detecting loss mechanisms of c-Si PV modules in-situ I-V measurement

    Science.gov (United States)

    Guo, Siyu; Schneller, Eric; Walters, Joe; Davis, Kristopher O.; Schoenfeld, Winston V.

    2016-09-01

    PV module reliability is alsways an important issue for PV industry. In an outdoor PV system, PV modules suffer from degradation due to different factors. It is then very important to determine the loss mechanisms of a PV module and making improvement based on this. It is found in this work that due to mismatch effect, using fitting method to extract I-V characteristics might not be well applied on a PV module, especially when it has non-uniform degradation problem. This work proposes a method to accurately quantify the power loss of PV modules due to different degradation mechanisms, including series resistance (Rs) loss, non-uniform shunting loss and number of shunted cells, uniform shunting loss, uniform current loss, non-uniform current (mismatch) loss, recombination current (J01 and J02) losses of a PV module. All required input information are the measured current-voltage (I-V) curves and short circuit current- open circuit voltage (Isc-Voc) of PV module initial state and final state. The method is first applied to a simulated PV module with various degradation problems. Power loss due to each loss mechanism for the simulated PV module is then extracted using the proposed method and a pie chart can be generated. Comparing with the actual power loss on each loss mechanism, the method proposed in this work is proved to be very accurate. The method is then further applied to a degradated PV module istalled in an outdoor PV system. The power loss on series resistance, shunting and current mismatch are effectively identified and the number of shunted cells is accurately calculated. In the real application, this method can be used in both indoor and outdoor characterization, which can be very beneficial for PV degradation analysis of PV modules and systems.

  11. 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...... clean ultra-high-vacuum conditions at room temperature. The I - V curves are found to he almost linear in contrast to previous reports. Tight-binding calculations of I - V curves for one- and two-atom contacts are in excellent agreement with our measurements. On the other hand, clearly nonlinear I - V...

  12. Electrical Characteristics of Co/n-Si Schottky Barrier Diodes Using I-V and C-V Measurements

    Institute of Scientific and Technical Information of China (English)

    G.Gfüler; (O).Güllü; (S).Karata(s); (O).F.Bakkalo(g)lu

    2009-01-01

    Electrical characteristics of Co/n-Si Schottky barrier diodes are analysed by current-voltage (I- V) and capacitancevoltage (C-V) techniques at room temperature.The electronic parameters such as ideality factor,barrier height and average series resistance are determined.The barrier height 0.76 eV obtained from the C-V measurements is higher than that of the value 0.70 eV obtained from the I-V measurements.The series resistance Rs and the ideality factor n are determined from the d ln( I ) / dV plot and are found to be 193.62Ω and 1.34,respectively.The barrier height and the Rs value are calculated from the H(I) - I plot and are found to be 0.71 eV and 205.95Ω.Furthermore,the energy distribution of the interface state density is determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height.The interface state density Nss ranges from 6.484×1011 cm-2eV-1 in (Ec-0.446) eV to 2.801×1010 cm-2eV-1 in (Ec-0.631) eV,of the Co/n-Si Schottky barrier diode.The results show the presence of a thin interracial layer between the metal and the semiconductor.

  13. 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.

  14. I-V measurements of Ge-Se-Sn chalcogenide glassy alloys

    Directory of Open Access Journals (Sweden)

    Vandana Kumari

    2015-03-01

    Full Text Available Current-voltage characteristics and DC electrical conductivity were studied for Ge30-xSe70Snx (x = 8, 11, 14, 17 and 20 glassy thin pellets of diameter 12 mm and thickness 1 mm prepared under a constant load of 5 tons using a well-known melt quenching technique in bulk as a function of composition. The I-V characteristics were recorded at room temperature as well as elevated temperatures up to 300 °C. The experimental data suggests that glass containing 20 at.% of Sn has the minimum resistance allowing maximum current through the sample as compared to other counterparts of the series. Therefore, DC conductivity is found to increase with increasing Sn concentration. Composition dependence of DC conductivity is discussed in terms of the bonding between Se and Sn. Plots between ln I and V1/2 provide linear relationship for both low and high voltage range. These results have been explained through the Pool-Frenkel mechanism. The I-V characteristics show ohmic behaviour in the low voltage range and this behaviour turns to non-ohmic from ohmic in the higher voltage range due to voltage induced temperature effects.

  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. Measurements and analysis of current-voltage characteristic of a pn diode for an undergraduate physics laboratory

    CERN Document Server

    Cataldo, Enrico; Maccarrone, Francesco; Paffuti, Giampiero

    2016-01-01

    We show that in a simple experiment at undergraduate level, suitable to be performed in classes of science and engineering students, it is possible to test accurately, on a popular 1N4148 p-n diode, the range of the junction currents where the Shockley equation model can be considered satisfactory. The experiment benefits from a system of temperature control and data collection driven in a LabVIEW environment. With these tools a large quantity of data can be recorded in the temporal frame of a lab session. Significant deviations of the experimental I-V with respect to the ideal behaviour curve predicted by the Shockley equation are observed, both at low and high current. A better agreement over the entire range is obtained introducing, as is customary, a four parameters model, including a parallel and a series resistance. A new iterative fitting procedure is presented which treats the I-V data of different regimes on the same level, and allows a simultaneous determination of the four parameters for each tempe...

  17. 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...

  18. 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

    (soiling, shading, discoloration). The premise of the method that is proposed is that different degradation modes affect the light and dark I-V characteristics of the PV module in different ways, leaving distinct signatures. This work focuses on identifying and correlating these specific signatures present......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...... in the light and dark I-V measurements, to specific degradation modes; a number of new dark I-V diagnostic parameters are proposed to quantify these signatures. The experimental results show that these dark I-V diagnostic parameters, complemented by light I-V performance and series resistance measurements can...

  19. Enhanced low current, voltage, and power dissipation measurements via Arduino Uno microcontroller with modified commercially available sensors

    Science.gov (United States)

    Tanner, Meghan; Eckel, Ryan; Senevirathne, Indrajith

    The versatility, simplicity, and robustness of Arduino microcontroller architecture have won a huge following with increasingly serious engineering and physical science applications. Arduino microcontroller environment coupled with commercially available sensors have been used to systematically measure, record, and analyze low currents, low voltages and corresponding dissipated power for assessing secondary physical properties in a diverse array of engineering systems. Setup was assembled via breadboard, wire, and simple soldering with an Arduino Uno with ATmega328P microcontroller connected to a PC. The microcontroller was programmed with Arduino Software while the bootloader was used to upload the code. Commercial Hall effect current sensor modules ACS712 and INA169 current shunt monitor was used to measure corresponding low to ultra-low currents and voltages. Stable measurement data was obtained via sensors and compared with corresponding oscilloscope measurements to assess reliability and uncertainty. Sensor breakout boards were modified to enhance the sensitivity of the measurements and to expand the applicability. Discussion of these measurements will focus on capabilities, capacities and limitations of the systems with examples of possible applications. Lock Haven Nanotechnology Program.

  20. 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...... or contacts are damaged/degraded). With the recent growth and development of new module level dc-dc optimizers and micro inverters, capable of bidirectional current flow, it is now possible to implement both dark I-V and light I-V measurements as complementary diagnostic tools. By complementing light I-V...... measurements, which reflect both the optical and electrical performance parameters of the PV device, with dark I-V measurements, which focus only on the electrical characteristic of the PV device, the optical factors determining power loss (such as partial shadows, soiling, discoloration of the plastic...

  1. Electrical Transport Characteristics of Pd/V/N-InP Schottky Diode From I-V-T and C-V-T Measurements

    Directory of Open Access Journals (Sweden)

    S. Sankar Naik

    2011-01-01

    Full Text Available The temperature dependence of current-voltage (I-V and capacitance-voltage (C-V characteristics of the Pd/V contacts on undoped n-type InP Schottky barrier diodes (SBDs have been systematically investigated in the temperature range of 200-400 K. The transition metal palladium (Pd is used as a second contact layer because it has high work function, it reacts with InP at low temperatures and improved contact morphology. The ideality factor (n and zero-bias barrier height are found to be strongly temperature dependent and while the zero-bias barrier height Φbo (I-V increases, the ideality factor n decreases with increasing temperature. The experimental values of BH and n for the devices are calculated as 0.48 eV (I-V, 0.85 eV (C-V and 4.87 at 200 K, 0.65 eV (I-V, 0.69 (C-V eV and 1.58 at 400 K respectively. The I-V characteristics are analyzed on the basis of thermionic emission (TE theory and the assumption of Gaussian distribution of barrier heights due to barrier inhomogeneities that prevail at the metal-semiconductor interface. The zero-bias barrier height Φbo versus 1/2kT plot has been drawn to obtain the evidence of a Gaussian distribution of the heights and the values of φ=0.89 eV and σ0= 145 meV for the mean barrier height and standard deviation. The conventional Richardson plot exhibits non-linearity with activation energy of 0.53 eV and the Richardson constant value of 4.25 × 10– 6 Acm– 2 K– 2. From the C-V characteristics, measured at 1 MHz the capacitance was determined to increase with increasing temperature. C-V measurements have resulted in higher barrier heights than those obtained from I-V measurements. As a result, it can be concluded that the temperature dependent characteristic parameters for Pd/V/n-InP SBDs can be successfully explained on the basis of TE mechanism with Gaussian distribution of the barrier heights.

  2. Zero-dipole molecular organic cations in mixed organic-inorganic halide perovskites: possible chemical solution for the reported anomalous hysteresis in the current-voltage curve measurements.

    Science.gov (United States)

    Giorgi, Giacomo; Yamashita, Koichi

    2015-11-06

    Starting from a brief description of the main architectures characterizing the novel solar technology of perovskite-based solar cells, we focus our attention on the anomalous hysteresis experimentally found to affect the measurement of the current-voltage curve of such devices. This detrimental effect, associated with slow dynamic reorganization processes, depends on several parameters; among them, the scan rate of the measurements, the architecture of the cell, and the perovskite deposition rate are crucial. Even if a conclusive explanation of the origin of the hysteresis has not been provided so far, several experimental findings ascribe its origin to ionic migration at an applied bias and dielectric polarization that occurs in the perovskite layer. Consistently, a dipole-moment-reduced cation such as formamidinium ion is experimentally reported to quantitatively reduce the hysteresis from perovskite-based devices. By means of a density-functional theory-based set of calculations, we have predicted and characterized guanidinium ion (GA = (+)[C(NH2)3], a zero-dipole moment cation by symmetry)-based organic-inorganic halide perovskite's structural and electronic properties, speculating that such a cation and the alloys it may form with other organic cations can represent a possible chemical solution for the puzzling issue of the hysteresis.

  3. Photovoltaic performance parameters at the nanoscale from in situ I-V curve measurements

    Science.gov (United States)

    Naseem, Sadia; Tennyson, Elizabeth; Leite, Marina

    Monocrystalline photovoltaic (PV) devices exhibit higher efficiencies than polycrystalline devices, but the high manufacturing costs associated with single crystal solar cells pose a hindrance to their wide implementation. Polycrystalline CuInxGa(1 - x)Se2 (CIGS) material with high optical absorbance and low cost/Watt, is a promising alternative. Yet, the efficiency of this low-cost technology is still substantially lower than the theoretical values estimated by the Shockley-Queisser limit. This is likely due to microstructural non-uniformities, which cannot be accessed by macroscopic light I-V measurements. Therefore, we spatially resolve the electrical response of these devices by `local' I-Vs. For that, we utilize a 100x objective as a local excitation source and LabVIEW to map the PV performance with sub-micronscale resolution through extrapolation of key parameters from pixel by pixel I-V curves. Extraction of performance parameters such as short-circuit current, opencircuit voltage fill factor, and maximum power point can provide useful information regarding optimal microstructural characteristics. This information is not only valuable for CIGS-based devices, but also will be an essential tool for maximizing performance across all PV technologies.

  4. Verification of a thermal interpretation of BSCCO-2223/Ag current voltage hysteresis

    Science.gov (United States)

    Sastry, P. V. P. S. S.; Nguyen, D. N.; Usak, P.; Schwartz, J.

    2004-03-01

    The current-voltage characteristic hysteresis of Bi-2223 tape in a silver matrix cooled by liquid nitrogen (LN2) at 77 K can be interpreted thermally, i.e. while the ramping-up temperature of the tape is higher than the ramping-down temperature for the same current levels. The reason for this could be hysteresis of the heat transfer coefficient. The coefficient is smaller during ramping up and larger (better cooling) during ramping down. To verify or deny this concept we have measured the surface temperature of the tape at LN2 temperature with and without a thermal insulation sheet upon the tape during ramping up over Ic and ramping down back under Ic. Different ramping rates were applied. The amplitudes of E on the tape was under 0.5 mV cm-1. In spite of measurement error and thermal fluctuations, we observed a difference between the surface temperature curve branch during ramping up and the higher branch during ramping down for a non-insulated tape. Furthermore, the measurements showed that a positive current-voltage (I-V) hysteresis pattern (with the down branch shifted to higher currents and smaller voltages) was observed even with thermal insulation. Under these conditions, however, the down branch of the temperature curve clearly revealed a higher temperature with respect to the up branch of the temperature, contrary to expectations of the thermal interpretation of I-V hysteresis. According to this result, the thermal concept of positive I-V hysteresis under stable cooling conditions can be denied. On the other hand, an accidental voltage drop in the I-V curve was observed on one degraded sample accompanied by a corresponding drop in temperature. This proves the thermal interpretation of voltage drops in I-V curves of locally degraded tapes.

  5. Verification of a thermal interpretation of BSCCO-2223/Ag current-voltage hysteresis

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, P V P S S [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); Nguyen, D N [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States); Usak, P [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, Bratislava, Sk84239 (Slovakia); Schwartz, J [Center for Advanced Power Systems, Florida State University, Tallahassee, FL 32310 (United States)

    2004-03-01

    The current-voltage characteristic hysteresis of Bi-2223 tape in a silver matrix cooled by liquid nitrogen (LN{sub 2}) at 77 K can be interpreted thermally, i.e. while the ramping-up temperature of the tape is higher than the ramping-down temperature for the same current levels. The reason for this could be hysteresis of the heat transfer coefficient. The coefficient is smaller during ramping up and larger (better cooling) during ramping down. To verify or deny this concept we have measured the surface temperature of the tape at LN{sub 2} temperature with and without a thermal insulation sheet upon the tape during ramping up over I{sub c} and ramping down back under I{sub c}. Different ramping rates were applied. The amplitudes of E on the tape was under 0.5 mV cm{sup -1}. In spite of measurement error and thermal fluctuations, we observed a difference between the surface temperature curve branch during ramping up and the higher branch during ramping down for a non-insulated tape. Furthermore, the measurements showed that a positive current-voltage (I-V) hysteresis pattern (with the down branch shifted to higher currents and smaller voltages) was observed even with thermal insulation. Under these conditions, however, the down branch of the temperature curve clearly revealed a higher temperature with respect to the up branch of the temperature, contrary to expectations of the thermal interpretation of I-V hysteresis. According to this result, the thermal concept of positive I-V hysteresis under stable cooling conditions can be denied. On the other hand, an accidental voltage drop in the I-V curve was observed on one degraded sample accompanied by a corresponding drop in temperature. This proves the thermal interpretation of voltage drops in I-V curves of locally degraded tapes.

  6. Field emission current-voltage curves as a diagnostic for scanning tunneling microscope tips

    Science.gov (United States)

    Meyer, J. A.; Stranick, S. J.; Wang, J. B.; Weiss, P. S.

    1991-12-01

    The current-voltage (I-V) characteristics of a low temperature ultrahigh vacuum scanning tunneling microscope (STM) tip positioned greater than 100 A from a planar surface have been recorded. We find curvature in the Fowler-Nordheim plots (log 10 I/V(sup 2) vs. I/V) due to the tip-plane geometry as has been predicted theoretically. Additionally, oscillations and sharp breaks in these I-V curves are observed over a wide voltage range, 50-1000 V. These I-V curves are used to characterize the STM tips prior to tunneling.

  7. Solar Cell Parameters Extraction from a Current-Voltage Characteristic Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Sanjaykumar J. Patel

    2013-05-01

    Full Text Available The determination of solar cell parameters is very important for the evaluation of the cell performance as well as to extract maximum possible output power from the cell. In this paper, we propose a computational based binary-coded genetic algorithm (GA to extract the parameters (I0, Iph and n for a single diode model of solar cell from its current-voltage (I-V characteristic. The algorithm was implemented using LabVIEW as a programming tool and validated by applying it to the I-V curve synthesized from the literature using reported values. The values of parameters obtained by GA are in good agreement with those of the reported values for silicon and plastic solar cells. change to “After the validation of the program, it was used to extract parameters for an experimental I-V characteristic of 4 × 4 cm2 polycrystalline silicon solar cell measured under 900 W/m. The I-V characteristic obtained using GA shows excellent match with the experimental one.

  8. Transient analysis of a PV power generator charging a capacitor for measurement of the I-V characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, Marwan M. [Energy Research Centre, An Najah National University, P.O. Box 721 Nablus (PS)

    2006-10-15

    Measuring the I-V characteristics is of high importance since it can be considered as a quality and performance certificate for each PV generator. The most precise and inexpensive measuring method is represented in capacitor charging by the PV generator. Using the equivalent circuit of the PV generator with a capacitor as load and applying transient analysis on the circuit, we obtain the capacitor charging voltage and current as a function of time, as well as their differentials as a function of short circuit current and capacitor size. The derived equations facilitate the calculation of proper capacitance size for measuring the I-V characteristics, and considers the acquisition speed of the measuring system as demonstrated through two measurement samples in this paper. The capacitor size is directly and indirectly proportional to the short circuit current and open circuit voltage of the PV generator, respectively. Accordingly, the paper presents a capacitance calculation chart, which enables selecting the correct capacitance for measuring the I-V characteristics by a computerized data acquisition system. (author)

  9. Current-voltage characteristics of double-strand DNA sequences

    Science.gov (United States)

    Bezerril, L. M.; Moreira, D. A.; Albuquerque, E. L.; Fulco, U. L.; de Oliveira, E. L.; de Sousa, J. S.

    2009-09-01

    We use a tight-binding formulation to investigate the transmissivity and the current-voltage (I-V) characteristics of sequences of double-strand DNA molecules. In order to reveal the relevance of the underlying correlations in the nucleotides distribution, we compare the results for the genomic DNA sequence with those of artificial sequences (the long-range correlated Fibonacci and Rudin-Shapiro one) and a random sequence, which is a kind of prototype of a short-range correlated system. The random sequence is presented here with the same first neighbors pair correlations of the human DNA sequence. We found that the long-range character of the correlations is important to the transmissivity spectra, although the I-V curves seem to be mostly influenced by the short-range correlations.

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

    DEFF Research Database (Denmark)

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

    2002-01-01

    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...... 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...... due to the applied bias voltage. For a armchair metallic nanotube, a reduction of current is observed with substitutional doping due to elastic backscattering by the impurity....

  11. Current-voltage characteristics of double-strand DNA sequences

    Energy Technology Data Exchange (ETDEWEB)

    Bezerril, L.M.; Moreira, D.A. [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970, Natal-RN (Brazil); Albuquerque, E.L., E-mail: eudenilson@dfte.ufrn.b [Departamento de Fisica, Universidade Federal do Rio Grande do Norte, 59072-970, Natal-RN (Brazil); Fulco, U.L. [Departamento de Biofisica e Farmacologia, Universidade Federal do Rio Grande do Norte, 59072-970, Natal-RN (Brazil); Oliveira, E.L. de; Sousa, J.S. de [Departamento de Fisica, Universidade Federal do Ceara, 60455-760, Fortaleza-CE (Brazil)

    2009-09-07

    We use a tight-binding formulation to investigate the transmissivity and the current-voltage (I-V) characteristics of sequences of double-strand DNA molecules. In order to reveal the relevance of the underlying correlations in the nucleotides distribution, we compare the results for the genomic DNA sequence with those of artificial sequences (the long-range correlated Fibonacci and Rudin-Shapiro one) and a random sequence, which is a kind of prototype of a short-range correlated system. The random sequence is presented here with the same first neighbors pair correlations of the human DNA sequence. We found that the long-range character of the correlations is important to the transmissivity spectra, although the I-V curves seem to be mostly influenced by the short-range correlations.

  12. 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...

  13. 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.

  14. Electrical Conductivity and Current-Voltage Characteristics of Individual Conducting Polymer PEDOT Nanowires

    Institute of Scientific and Technical Information of China (English)

    LONG Yun-Ze; DUVAIL Jean-Luc; CHEN Zhao-Jia; JIN Ai-Zi; GU Chang-Zhi

    2008-01-01

    We report the current-voltage (I-V) characteristics and electrical conductivity of individual template-synthesized poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires (190 ± 6 nm in diameter and σRT : 11.2±2Ω-1cm-1)over a wide temperature range from 300 to 10K. With lowering temperature, the Ⅰ- Ⅴ characteristics become nonlinear around 50 K, and a clear Coulomb gap-like structure appears in the differential conductance (dI/dV)spectra. The temperature dependence of the resistance below 70 K follows ln R ∝ T-1/2, which can be interpreted as Efros-Shklovskii hopping conduction in the presence of a Coulomb gap. In addition, the influences of measurement methods such as the applied bias voltage magnitude, the two-probe and four-probe techniques used in the resistance measurements are also reported and discussed.

  15. Measurement of Solar Cell Parameters with Dark Forward I-V Characteristics

    Directory of Open Access Journals (Sweden)

    J. Salinger

    2006-01-01

    Full Text Available The grade of a solar cell depends mainly on the quality of the starting material. During the production of this material, many impurities are left in the bulk material and form defect levels in the band-gap, which act as generation-recombination centers or charge carrier traps. These levels influence the efficiency of solar cells. Therefore knowledge of the parameters of these levels, e.g., energy position, capture cross section and concentration, is very useful for solar cell engineering. In this paper emphasis is placed on a simple and fast method for obtaining these parameters, namely measurements of dark characteristics. Preliminary results are introduced, together with the difficulties and limits of this method. 

  16. 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.

  17. 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.

  18. 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...

  19. Characterization of AlN/AlGaN/GaN:C heterostructures grown on Si(111) using atom probe tomography, secondary ion mass spectrometry, and vertical current-voltage measurements

    Energy Technology Data Exchange (ETDEWEB)

    Huber, Martin, E-mail: martin.huberVIH@infineon.com [Infineon Technologies Austria AG, Siemensstrasse 2, A-9500 Villach, Austria and Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz (Austria); Daumiller, Ingo; Andreev, Andrei; Silvestri, Marco; Knuuttila, Lauri; Lundskog, Anders [Infineon Technologies Austria AG, Siemensstrasse 2, A-9500 Villach (Austria); Wahl, Michael; Kopnarski, Michael [IFOS Institut fuer Oberflaechen- und Schichtanalytik GmbH, Trippstadter Strasse 120, D-67663 Kaiserslautern (Germany); Bonanni, Alberta [Institute of Semiconductor and Solid State Physics, Johannes Kepler University, Altenbergerstrasse 69, A-4040 Linz (Austria)

    2016-03-28

    Complementary studies of atom probe tomography, secondary ion mass spectrometry, and vertical current-voltage measurements are carried out in order to unravel the influence of C-doping of GaN on the vertical leakage current of AlN/AlGaN/GaN:C heterostructures. A systematic increment of the vertical blocking voltage at a given current density is observed in the structures, when moving from the nominally undoped conditions—corresponding to a residual C-background of ∼10{sup 17 }cm{sup −3}—to a C-content of ∼10{sup 19 }cm{sup −3} in the GaN layer. The value of the vertical blocking voltage saturates for C concentrations higher than ∼10{sup 19 }cm{sup −3}. Atom probe tomography confirms the homogeneity of the GaN:C layers, demonstrating that there is no clustering at C-concentrations as high as 10{sup 20 }cm{sup −3}. It is inferred that the vertical blocking voltage saturation is not likely to be related to C-clustering.

  20. A novel method for measuring carrier lifetime and capture cross-section by using the negative resistance I-V characteristics of a barrier-type thyristor

    Energy Technology Data Exchange (ETDEWEB)

    Li Hairong; Li Siyuan, E-mail: hrli@lzu.edu.c [Institute of Microelectronics, Lanzhou University, Lanzhou 730000 (China)

    2010-08-15

    A brand new and feasible method for measuring the carrier lifetime and capture cross-section of a barrier by using the negative resistance segment of the I-V characteristics of a barrier-type thyristor (BTH) is put forward. The measuring principle and calculation method are given. The BTH samples are experimentally measured and the results are analyzed in detail. (semiconductor devices)

  1. Defect Measurements and Performance Testing of CZT Detectors Using I-DLTS, TCT, I-V, C-V and γ-Ray Spectroscopy

    Science.gov (United States)

    Gul, Rubi; Li, Zheng; Keeter, Kara; Rodriguez, Rene; James, Ralph

    2008-05-01

    Performance testing and the measurement of the defect levels of CZT detectors from different manufacturers are investigated by means of I-DLTS (Current Deep Level Transient Spectroscopy), TCT (Transient Charge Technique), I-V, C-V and γ-Ray Spectroscopy. Studies include measuring defects parameters such as energy levels in the band gap, carrier capture cross-section and defect density have been determined by using I-DLTS. The space charge density, induced current and collected charge were obtained by using TCT. Detector's electric characteristics and detection performance tests are carried out by using I-V, C-V and γ-Ray Spectroscopy. I-DLTS data is collected in the temperature range of 10-330 K. Different mid-band energy traps, ranging from Ec-0.01 eV to Ec-0.31 eV, mostly native acceptor defects, are identified. The TCT parameters are obtained by measuring laser induced current transients with 50-1100 V bias voltages across the detector. The maximum value of collected electrons and the typical measured space charge density, at 1100V is found of the order of 10^10. Resistivity, performance and depletion of the detectors are determined by I-V and γ-Ray Spectroscopy.

  2. 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.

  3. Effect of Light Intensity and Temperature on the Current Voltage Characteristics of Al/ SY/ p- Si Organic-Inorganic Heterojunction

    Science.gov (United States)

    Imer, Arife Gencer; Ocak, Yusuf Selim

    2016-10-01

    An organic-inorganic contact was fabricated by forming a thin film of sunset yellow dye ( SY) on a p- Si wafer. The device showed a good rectification property, and the sunset yellow thin film modified the barrier height (Φb) of Al/ p- Si contact by influencing the space charge region. The heterojunction had a strong response to the different illumination intensities and showed that it can be suitable for photodiode applications. The I- V measurements of the device were also applied in the temperature range of 100-500 K. It was seen that characteristic parameters of the device were strongly dependent upon temperature. While the value of Φb increased, the ideality factor ( n) decreased with the increase in temperature. This variation was attributed to spatial inhomogeneity at the interface. The Norde function was used to determine the temperature-dependent series resistance and Φb values, and there was a good agreement with that of ln I- V data. The values of the Richardson constant ( A*) and mean Φb were determined as 29.47 Acm-2 K-2 by means of a modified activation energy plot, matching with a theoretical one, and 1.032 eV, respectively. Therefore, it was stated that the current voltage characteristic with the temperature can be explained by thermionic emission theory with Gaussian distribution of the Φb at the interface.

  4. Modelling of Chirality-Dependent Current-Voltage Characteristics of Carbon-Nanotube Field-Effect Transistors

    Institute of Scientific and Technical Information of China (English)

    ZHAO Xu; WANG Yan; YU Zhi-Ping

    2006-01-01

    @@ Current-voltage characteristics of ballistic carbon-nanotube field-effect transistors are characterized with an it-erative simulation program. The influence of carbon-nanotube chirality and diameter on the output current is considered. An analytical current-voltage expression under the quantum capacitance limit and low-voltage application is derived. Our simulation results are compared with actual measurement data.

  5. Defect Measurements of CdZnTe Detectors Using I-DLTS, TCT, I-V and Gamma-ray Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Gul,R.

    2008-08-11

    In this work we measured the crystal defect levels and tested the performance of CdZnTe detectors by diverse methodologies, viz., Current Deep Level Transient Spectroscopy (I-DLTS), Transient Current Technique (TCT), Current and Capacitance versus Voltage measurements (I-V and C-V), and gamma-ray spectroscopy. Two important characteristics of I-DLTS technique for advancing this research are (1) it is applicable for high-resistivity materials (>10{sup 6} {Omega}-cm), and, (2) the minimum temperature for measurements can be as low as 10 K. Such low-temperature capability is excellent for obtaining measurements at shallow levels. We acquired CdZnTe crystals grown by different techniques from two different vendors and characterized them for point defects and their response to photons. I-DLTS studies encompassed measuring the parameters of the defects, such as the energy levels in the band gap, the carrier capture cross-sections and their densities. The current induced by the laser-generated carriers and the charge collected (or number of electrons collected) were obtained using TCT that also provides the transport properties, such as the carrier life time and mobility of the detectors under study. The detector's electrical characteristics were explored, and its performance tested using I-V, C-V and gamma-ray spectroscopy.

  6. Defect measurements of CdZnTe detectors using I-DLTS, TCT, I-V, C-V and γ-ray spectroscopy

    Science.gov (United States)

    Gul, R.; Li, Z.; Rodriguez, R.; Keeter, K.; Bolotnikov, A.; James, R.

    2008-08-01

    In this work we measured the crystal defect levels and tested the performance of CdZnTe detectors by diverse methodologies, viz., Current Deep Level Transient Spectroscopy (I-DLTS), Transient Current Technique (TCT), Current and Capacitance versus Voltage measurements (I-V and C-V), and gamma-ray spectroscopy. Two important characteristics of I-DLTS technique for advancing this research are (1) it is applicable for high-resistivity materials (>106 Ω-cm), and, (2) the minimum temperature for measurements can be as low as 10 K. Such low-temperature capability is excellent for obtaining measurements at shallow levels. We acquired CdZnTe crystals grown by different techniques from two different vendors and characterized them for point defects and their response to photons. I-DLTS studies encompassed measuring the parameters of the defects, such as the energy levels in the band gap, the carrier capture cross-sections and their densities. The current induced by the laser-generated carriers and the charge collected (or number of electrons collected) were obtained using TCT that also provides the transport properties, such as the carrier life time and mobility of the detectors under study. The detector's electrical characteristics were explored, and its performance tested using I-V, C-V and gamma-ray spectroscopy.

  7. 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)

  8. 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.

  9. Current-voltage curve of a bipolar membrane at high current density

    NARCIS (Netherlands)

    Aritomi, T.; Boomgaard, van den Th.; Strathmann, H.

    1996-01-01

    The potential drop across a bipolar membrane was measured as a function of the applied current density. As a result, an inflection point was observed in the obtained current-voltage curve at high current density. This inflection point indicates that at high current densities water supply from outsid

  10. Current-voltage curve of a bipolar membrane at high current density

    NARCIS (Netherlands)

    Aritomi, T.; van den Boomgaard, Anthonie; Strathmann, H.

    1996-01-01

    The potential drop across a bipolar membrane was measured as a function of the applied current density. As a result, an inflection point was observed in the obtained current-voltage curve at high current density. This inflection point indicates that at high current densities water supply from

  11. Simulation of current-voltage curves for inverted planar structure perovskite solar cells using equivalent circuit model with inductance

    Science.gov (United States)

    Cojocaru, Ludmila; Uchida, Satoshi; Jayaweera, Piyankarage V. V.; Kaneko, Shoji; Toyoshima, Yasutake; Nakazaki, Jotaro; Kubo, Takaya; Segawa, Hiroshi

    2017-02-01

    Physical modeling of hysteretic behavior in current-voltage (I-V) curves of perovskite solar cells (PSCs) is necessary for further improving their power conversion efficiencies (PCEs). The reduction of hysteresis in inverted planar structure PSCs (p-PSCs) has been achieved by using a [6,6]-phenyl-C61-butyric acid methyl ester (PCBM) layer. In the cases, the opposite trend of the I-V hysteresis has been observed where the forward scan shows slightly higher efficiency than the reverse scan. In this paper, an equivalent circuit model with inductance is proposed. This model consists of a Schottky diode involving a parasitic inductance focusing PCBM/Al(Ca) interface and accurately represents the opposite trend of the I-V hysteresis of the p-PSC with an inverted structure.

  12. 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...

  13. Luminescence, radiative recombination, and current voltage characteristics in sensitized TiO2 solar cells

    Science.gov (United States)

    Smestad, Greg P.

    1992-12-01

    A connection is made between the luminescence or radiative recombination in an absorber material and the current voltage characteristics of a quantum converter of light. A relationship between luminescence and voltage is derived, using detailed balance and the chemical potential of the excitation, which is similar to that obtained using the techniques of Shockley and Queisser or R. T. Ross. This model relates the absorptivity and photoluminescence efficiency of the light absorber to the I V curve. In this way both thermodynamic properties, or voltage, and the kinetics, or charge transfer and current, can be combined in order to optimize materials and configurations. The model is applied to dye sensitized Ti02 solar cells, and compared with preliminary experimental data for Ru based charge transfer dyes and inorganic compounds. The luminescence model is found to be applicable to dye sensitized converters, as well as to standard silicon solar cells, light detectors, and LEDs.

  14. 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.

  15. Experimental observation of direct current voltage-induced phase synchronization

    Indian Academy of Sciences (India)

    Haihong Li; Weiqing Liu; Qiongling Dai; Jinghua Xiao

    2006-09-01

    The dynamics of two uncoupled distinct Chua circuits driven by a common direct current voltage is explored experimentally. It was found that, with increasing current intensity, the dominant frequencies of these two Chua circuits will first vary at different speeds, approach an identical value for a certain current intensity and then separate. Techniques such as synchronization index and phase difference distribution were employed to analyze the phase coherence between these two Chua circuits.

  16. Modeling and extraction technique for parasitic resistances in MOSFETs Combining DC I-V and low frequency C-V measurement

    Science.gov (United States)

    Shin, Ja Sun; Bae, Hagyoul; Hong, Euiyoun; Jang, Jaeman; Yun, Daeyoun; Lee, Jieun; Kim, Dae Hwan; Kim, Dong Myong

    2012-06-01

    Accurate extraction of parasitic gate (RG), source (RS), drain (RD), and substrate (Rsub) resistances in MOSFETs is important in the modeling and characterization for DC and RF applications. Combining DC current-voltage and low-frequency capacitance-voltage characteristics with an equivalent circuit, we report a simple technique for a complete and separate extraction of parasitic resistances (RG, RS, RD, and Rsub) in individual MOSFETs without employing multiple devices or complicated S-parameter characterization with various device combinations. Intrinsic spreading component is also separated from the contact-related extrinsic component in RS and RD.

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

    Energy Technology Data Exchange (ETDEWEB)

    Shukrinov, Yu M [BLTP, JINR, Dubna, Moscow Region, 141980 (Russian Federation); Mahfouzi, F [Institute for Advanced Studies in Basic Sciences, PO Box 45195-1159, Zanjan (Iran, Islamic Republic of)

    2007-02-15

    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.

  18. Branching in current voltage characteristics of intrinsic Josephson junctions

    Science.gov (United States)

    Shukrinov, Yu M.; Mahfouzi, F.

    2007-02-01

    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.

  19. Comparative study of Cu(In,Ga)Se{sub 2}/(PVD)In{sub 2}S{sub 3} and Cu(In,Ga)Se{sub 2}/(CBD)CdS heterojunction based solar cells by admittance spectroscopy, current-voltage and spectral response measurements

    Energy Technology Data Exchange (ETDEWEB)

    Darga, A. [Laboratoire de Genie Electrique de Paris, CNRS UMR8507, SUPELEC, UPMC Univ Paris 06, Univ Paris-Sud, 11 rue Joliot-Curie, Plateau de Moulon, F-91192 Gif-sur-Yvette Cedex (France)], E-mail: arouna.darga@lgep.supelec.fr; Mencaraglia, D.; Djebbour, Z.; Dubois, A. Migan; Chouffot, R.; Serhan, J. [Laboratoire de Genie Electrique de Paris, CNRS UMR8507, SUPELEC, UPMC Univ Paris 06, Univ Paris-Sud, 11 rue Joliot-Curie, Plateau de Moulon, F-91192 Gif-sur-Yvette Cedex (France); Couzinie-Devy, F.; Barreau, N.; Kessler, J. [Institut des Materiaux Jean Rouxel (IMN)-UMR 6502, Universite de Nantes, CNRS, 2 rue de la Houssiniere, BP 32229, 44322 Nantes cedex 3 (France)

    2009-02-02

    Co-evaporated Cu(In,Ga)Se{sub 2} (CIGSe) based solar cells with Physical Vapour Deposited (PVD) Indium Sulphide (In{sub 2}S{sub 3}) as buffer layer have been studied by admittance spectroscopy and current-voltage characteristics measurements. The results have been compared to those obtained with a reference CBD-CdS/CIGSe device. In darkness, the PVD-In{sub 2}S{sub 3} buffer layer devices exhibit higher densities of trapping defects and low values of shunt resistance. However, under illumination we have observed an important improvement of the In{sub 2}S{sub 3}/CIGSe electronic transport properties. This behavior seems to be linked to the presence of a metastable defect with activation energy of 0.3 eV.

  20. Diagnostics of defects in AlGaN/GaN high electron mobility transitor (HEMT) epi-layers via spectroscopic photo current-voltage (IV) measurements with variable-wavelength ultraviolet (UV) and visible light excitation

    Science.gov (United States)

    Khanal, Min P.; Ozden, Burcu; Mirkhani, Vahid; Yapabandara, Kosala; Shehzad Sultan, Muhammad; Park, Minseo; Shen, Li

    The reliability and performance of the nitride high electron mobility transistors (HEMTs) have been plagued by deleterious phenomena such as current collapse which is believed to be produced by electrically-active deep-level defects (or traps) that reside at the surface/interfaces and in the bulk of the AlGaN/GaN HEMT layers. Therefore, identification of their physical/spectral locations and understanding the nature of defects is very important to improve the reliability of AlGaN/GaN HEMTs. In this work, deep-level defects and traps located in the AlGaN/GaN HEMT epi-layers were investigated by using spectroscopic photo IV measurements. An array of Schottky contacts was constructed on the HEMT layer produced by metal-organic chemical vapor deposition (MOCVD). The photo IV measurement was performed by collecting the photo current generated by the variable-wavelength UV/visible light illumination. It was successfully demonstrated that this technique can provide the information on the distribution of electrically-active defects along the in-depth direction and across the HEMT wafers. Therefore, it can be concluded that the spectroscopic measurements can be useful to assess the uniformity of defect distribution both along the in-depth direction and across the AlGaN/GaN wafers. Corresponding author.

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

    Energy Technology Data Exchange (ETDEWEB)

    Feron, K., E-mail: Krishna.Feron@csiro.au; Fell, C. J. [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia); CSIRO Energy Flagship, Newcastle, NSW 2300 (Australia); Zhou, X.; Belcher, W. J.; Dastoor, P. C. [Centre for Organic Electronics, University of Newcastle, Callaghan, NSW 2308 (Australia)

    2014-12-07

    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.

  2. Changes in haematology measurements with the Sysmex XT-2000iV during storage of feline blood sampled in EDTA or EDTA plus CTAD.

    Science.gov (United States)

    Granat, Fanny; Geffré, Anne; Bourgès-Abella, Nathalie; Braun, Jean-Pierre; Trumel, Catherine

    2013-06-01

    In veterinary medicine a complete blood cell count (CBC) cannot always be performed within 24 h as usually recommended, particularly for specimens shipped to a reference laboratory. This raises the question of the stability of the variables, especially in ethylenediamine tetra-acetic acid (EDTA) feline blood specimens, known to be prone to in vitro platelet aggregation. Citrate, theophylline, adenosine and dipyridamole (CTAD) has been reported to limit platelet aggregation in feline blood specimens. The aim of this study was to measure the stability of the haematological variables and the platelet aggregation score in EDTA and EDTA plus CTAD (EDCT) feline blood specimens during 48 h of storage at room temperature. Forty-six feline EDTA and EDCT blood specimens were analysed with a Sysmex XT-2000iV analyser, and the platelet count and score of platelet aggregation were estimated immediately and after 24 and 48 h of storage. A significant increase in mean corpuscular volume, haematocrit, reticulocyte and eosinophil counts, and a significant decrease in mean corpuscular haemoglobin concentration and monocyte count were observed. Haemoglobin, mean corpuscular haemoglobin, and red blood cell, white blood cell, neutrophil and lymphocyte counts remained stable. Changes in reticulocyte indexes with time (low fluorescence ratio, medium fluorescence ratio, high fluorescence ratio and immature reticulocyte fraction) were not significant. Changes were generally more pronounced in EDTA than in EDCT. Platelet aggregation decreased markedly in initially highly aggregated EDTA specimens, and increased slightly in initially non- or mildly-aggregated EDTA or EDCT specimens. Platelet counts increased and decreased, or remained stable, respectively. CTAD can reduce storage-induced changes of the haematological variables in feline samples, thus improving the reliability of a CBC and limiting clinical misinterpretations.

  3. 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)

  4. The effect of used deformation, metal sheath and heat treatment on the I-V curve of ex situ MgB 2 composite

    Science.gov (United States)

    Kováč, P.; Hušek, I.; Melišek, T.

    2004-01-01

    Current-voltage characteristics of MgB 2 composite wires made of ex situ process using Cu, Fe and stainless steel (SS) sheaths have been measured at 4.2 K in the self-field and external magnetic field between 2 and 4 T. It was found that the used mode of deformation (drawing, rotary swaging and two-axial rolling) influences the slope of I-V curve due to affected grain connectivity. Final heat treatment at 950 °C/0.5 h improves grain connectivity apparently, which results in I-V characteristic with very high n-exponents. The n-exponents of multi-core wires measured in external field are apparently lower due to a current sharing among the non-uniform filaments surrounded by high resistance matrix.

  5. A linear auroral current-voltage relation in fluid theory

    Directory of Open Access Journals (Sweden)

    J. Vedin

    2004-04-01

    Full Text Available Progress in our understanding of auroral currents and auroral electron acceleration has for decades been hampered by an apparent incompatibility between kinetic and fluid models of the physics involved. A well established kinetic model predicts that steady upward field-aligned currents should be linearly related to the potential drop along the field line, but collisionless fluid models that reproduce this linear current-voltage relation have not been found. Using temperatures calculated from the kinetic model in the presence of an upward auroral current, we construct here approximants for the parallel and perpendicular temperatures. Although our model is rather simplified, we find that the fluid equations predict a realistic large-scale parallel electric field and a linear current-voltage relation when these approximants are employed as nonlocal equations of state. This suggests that the concepts we introduce can be applied to the development of accurate equations of state for fluid simulations of auroral flux tubes.

    Key words. Magnetospheric physics (auroral phenomena; magnetosphere-ionosphere interactions – Space plasma physics (kinetic and MHD theory

  6. Current-voltage characteristics of borophene and borophane sheets.

    Science.gov (United States)

    Izadi Vishkayi, Sahar; Bagheri Tagani, Meysam

    2017-08-16

    Motivated by recent experimental and theoretical research on a monolayer of boron atoms, borophene, the current-voltage characteristics of three different borophene sheets, 2Pmmn, 8Pmmn, and 8Pmmm, are calculated using density functional theory combined with the nonequilibrium Green's function formalism. Borophene sheets with two and eight atoms in a unit cell are considered. Their band structure, electron density, and structural anisotropy are analyzed in detail. The results show that the 8Pmmn and 8Pmmm structures that have eight atoms in the unit cell have less anisotropy than 2Pmmn. In addition, although 8Pmmn shows a Dirac cone in the band structure, its current is lower than that of the other two. We also consider a fully hydrogenated borophene, borophane, and find that the hydrogenation process reduces the structural anisotropy and the current significantly. Our findings reveal that the current-voltage characteristics of the borophene sheets can be used to detect the type and the growth direction of the sample because it is strongly dependent on the direction of the electron transport, anisotropy, and details of the unit cell of the borophene.

  7. Coupling of intrinsic Josephson junctions and subgap structure in the current-voltage characteristics of high-T{sub c} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shukrinov, Yu.M. [Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of); Physical Technical Institute of Tajik Academy of Sciences, Dushanbe (Tajikistan); Nasrulaev, Kh. [Physical Technical Institute of Tajik Academy of Sciences, Dushanbe (Tajikistan); Sargolzaei, M. [Institute for Advanced Studies in Basic Sciences, Zanjan (Iran, Islamic Republic of); Oya, G.; Irie, A. [Utsunomiya University, Yoto, Utsunomiya (Japan); CREST, Japan Science and Technology Corporation (JST), Kawaguchi, Saitama (Japan)

    2002-01-01

    The subgap structure in current-voltage (I-V) characteristics of a stack of intrinsic Josephson junctions in high-T{sub c} superconductors is studied. An analytical formula for the I-V characteristics is obtained which had taken into account the influence of the dynamically breaking of charge neutrality (DBCN) in CuO{sub 2} layers on the subgap structure. It is shown that DBCN does not affect the positions and the amplitudes of the subgap peaks, but changes the curvature of the branches in the I-V characteristics. As a possible manifestation of the non-equivalence of the junction, the experimental I-V characteristics of intrinsic Josephson junctions are presented. (author)

  8. Experimental manifestation of the breakpoint region in the current-voltage characteristics of intrinsic Josephson junctions

    OpenAIRE

    Irie, A.; Shukrinov, Yu M.; Oya, G.

    2008-01-01

    The experimental evidence of the breakpoint on the current-voltage characteristics (IVCs) of the stacks of intrinsic Josephson junctions (IJJs) is presented. The influence of the capacitive coupling on the IVCs of Bi$_2$Sr$_2$CaCu$_2$O$_y$ IJJs has been investigated. At 4.2 K, clear breakpoint region is observed on the branches in the IVCs. It is found that the hysteresis observed on the IVC is suppressed due to the coupling compared with that expected from the McCumber parameter. Measurement...

  9. Experimental manifestation of the breakpoint region in the current-voltage characteristics of intrinsic Josephson junctions

    Science.gov (United States)

    Irie, A.; Shukrinov, Yu. M.; Oya, G.

    2008-10-01

    The experimental evidence of the breakpoint on the current-voltage characteristics (IVCs) of the stacks of intrinsic Josephson junctions (IJJs) is presented. The influence of the capacitive coupling on the IVCs of Bi2Sr2CaCu2Oy IJJs has been investigated. At 4.2K, clear breakpoint region is observed on the branches in the IVCs. It is found that due to the coupling between junctions, the hysteresis observed on the IVC is small compared to that expected from the McCumber parameter. Measurements agree well with the results predicted by the capacitively coupled Josephson junction model including the diffusion current.

  10. Improved analytical current voltage characteristics of a solar cell

    Energy Technology Data Exchange (ETDEWEB)

    Yli-Koski, M.; Tuominen, E.; Acerbis, M.; Sinkkonen, J.

    1997-12-31

    Application of the Green`s function method to the calculation of the current voltage characteristics of a pn-junction solar cell makes possible to extract more reliable and exact information about the behavior of the cell. With this method not only the minority carrier diffusion currents but also the drift currents in quasi- neutral regions of the solar cell can be taken into consideration. Furthermore, this approach is not limited to an exponentially decaying minority carrier generation function but is valid for any type of optical generation. In addition, the injection boundary condition is exploited with the result that not only the pn-diode current but also the current resulting from the optical generation depends on the voltage of the solar cell. Applying the method also gives the so called position dependent collection efficiency function which is defined as the probability that an electron-hole pair created at a certain point inside the solar cell will contribute to the current leaving the cell. (orig.) 15 refs.

  11. Phase-field modeling of switchable diode-like current-voltage characteristics in ferroelectric BaTiO3

    Science.gov (United States)

    Cao, Y.; Shen, J.; Randall, C. A.; Chen, L. Q.

    2014-05-01

    A self-consistent model has been proposed to study the switchable current-voltage (I-V) characteristics in Cu/BaTiO3/Cu sandwiched structure combining the phase-field model of ferroelectric domains and diffusion equations for ionic/electronic transport. The electrochemical transport equations and Ginzburg-Landau equations are solved using the Chebyshev collocation algorithm. We considered a single parallel plate capacitor configuration which consists of a single layer BaTiO3 containing a single tetragonal domain orientated normal to the plate electrodes (Cu) and is subject to a sweep of ac bias from -1.0 to 1.0 V at 25 °C. Our simulation clearly shows rectifying I-V response with rectification ratios amount to 102. The diode characteristics are switchable with an even larger rectification ratio after the polarization direction is flipped. The effects of interfacial polarization charge, dopant concentration, and dielectric constant on current responses were investigated. The switchable I-V behavior is attributed to the polarization bound charges that modulate the bulk conduction.

  12. Investigation of Current-Voltage Characteristics of Ni/GaN Schottky Barrier Diodes for Potential HEMT Applications

    Directory of Open Access Journals (Sweden)

    Ashish Kumar

    2011-01-01

    Full Text Available In the present work, the I-V characteristics of Ni/GaN Schottky diodes have been studied. The Schottky diodes, having different sizes using Ni/Au and ohmic contacts using Ti/Al/Ni/Au were made on n-GaN. The GaN was epitaxially grown on c-plane sapphire by metal organic chemical vapor deposition (MOCVD technique and had a thickness of about 3.7 µm. The calculated ideality factor and barrier height from current-voltage (I-V characteristics (at 300 K for two GaN Schottky diodes were close to ~1.3 and ~ 0.8 eV respectively. A high reverse leakage current in the order of 10 – 4A/cm2 (at – 1 V was observed in both diodes. A careful analysis of forward bias I-V characteristics showed very high series resistance and calculation for ideality factor indicated presence of other current transport mechanism apart from thermionic model at room temperature.

  13. 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.

  14. Light regulated I-V hysteresis loop of Ag/BiFeO3/FTO thin film

    Science.gov (United States)

    Wei, Lujun; Sun, Bai; Zhao, Wenxi; Li, Hongwei; Chen, Peng

    2017-01-01

    A hysteresis loop of current-voltage characteristics based multiferroic BiFeO3 nanoribbons memory device is observed. Moreover, the white-light can greatly regulate both the current-voltage hysteresis loop and the ferroelectric hysteresis loop. The stored space charges within the electrodes/BiFeO3 interface can lead to hysteresis-type I-V characteristics of Ag/BiFeO3/FTO devices. The white-light controlled I-V loop and ferroelectric loop result from photon-generated carries. Since the I-V hysteresis loop and ferroelectric hysteresis loop have a potential application prospect to the memory devices, these two white-light controlled the hysteresis loops curves are likely to provide promising opportunity for developing the multi-functional memory devices.

  15. Current-voltage characteristics and transition voltage spectroscopy of individual redox proteins.

    Science.gov (United States)

    Artés, Juan M; López-Martínez, Montserrat; Giraudet, Arnaud; Díez-Pérez, Ismael; Sanz, Fausto; Gorostiza, Pau

    2012-12-19

    Understanding how molecular conductance depends on voltage is essential for characterizing molecular electronics devices. We reproducibly measured current-voltage characteristics of individual redox-active proteins by scanning tunneling microscopy under potentiostatic control in both tunneling and wired configurations. From these results, transition voltage spectroscopy (TVS) data for individual redox molecules can be calculated and analyzed statistically, adding a new dimension to conductance measurements. The transition voltage (TV) is discussed in terms of the two-step electron transfer (ET) mechanism. Azurin displays the lowest TV measured to date (0.4 V), consistent with the previously reported distance decay factor. This low TV may be advantageous for fabricating and operating molecular electronic devices for different applications. Our measurements show that TVS is a helpful tool for single-molecule ET measurements and suggest a mechanism for gating of ET between partner redox proteins.

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

    Energy Technology Data Exchange (ETDEWEB)

    Islam, S. M. Z. [IUSL, Department of Physics, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Department of Physics and Engineering Physics, Fordham University, 441 E. Fordham Road, Bronx, New York 10458 (United States); Department of Electrical Engineering, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Gayen, Taposh [IUSL, Department of Physics, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Department of Physics and Engineering Physics, Fordham University, 441 E. Fordham Road, Bronx, New York 10458 (United States); Tint, Naing; Alfano, Robert, E-mail: ralfano@sci.ccny.cuny.edu [IUSL, Department of Physics, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Department of Electrical Engineering, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Shi, Lingyan [IUSL, Department of Physics, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Department of Biomedical Engineering, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States); Seredych, Mykola; Bandosz, Teresa J. [Department of Chemistry, The City College of New York, 160 Convent Ave., New York, New York 10031 (United States)

    2014-11-07

    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{sup 2}) are reported here, while using potassium iodide as an electrolyte. The output photocurrent, I (μA) with input power, P (mW/cm{sup 2}) is found to be superlinear, showing a relation of I = P{sup n}, where n = 1.4.

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

    Science.gov (United States)

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

    2014-11-01

    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/cm2) are reported here, while using potassium iodide as an electrolyte. The output photocurrent, I (μA) with input power, P (mW/cm2) is found to be superlinear, showing a relation of I = Pn, where n = 1.4.

  18. Current-voltage characteristics in macroporous silicon/SiOx/SnO2:F heterojunctions.

    Science.gov (United States)

    Garcés, Felipe A; Urteaga, Raul; Acquaroli, Leandro N; Koropecki, Roberto R; Arce, Roberto D

    2012-07-25

    We study the electrical characteristics of macroporous silicon/transparent conductor oxide junctions obtained by the deposition of fluorine doped-SnO2 onto macroporous silicon thin films using the spray pyrolysis technique. Macroporous silicon was prepared by the electrochemical anodization of a silicon wafer to produce pore sizes ranging between 0.9 to 1.2 μm in diameter. Scanning electronic microscopy was performed to confirm the pore filling and surface coverage. The transport of charge carriers through the interface was studied by measuring the current-voltage curves in the dark and under illumination. In the best configuration, we obtain a modest open-circuit voltage of about 70 mV and a short-circuit current of 3.5 mA/cm2 at an illumination of 110 mW/cm2. In order to analyze the effects of the illumination on the electrical properties of the junction, we proposed a model of two opposing diodes, each one associated with an independent current source. We obtain a good accordance between the experimental data and the model. The current-voltage curves in illuminated conditions are well fitted with the same parameters obtained in the dark where only the photocurrent intensities in the diodes are free parameters.

  19. I vælten

    DEFF Research Database (Denmark)

    Petersen, Morten Krogh; Munk, Anders Kristian

    2013-01-01

    Med udgangspunkt i to eksempler fra brugerdrevne innovationsprojekter diskuterer vi, hvad det vil sige at bedrive kulturanalyse, når opgaven er, at skabe forandring i hverdagspraksisser. Hvad end det drejer sig om nye skraldespande eller om nye baderum, så giver eksemplerne et indblik i, hvad det...... er virksomheder og offentlige instanser vil med kulturanalysen og hvorfor, de i stigende grad inviterer den til at bidrage til deres arbejde. Samtidig udstiller eksemplerne også nogle af de vanskeligheder, som kulturanalysen bliver bragt i, når den på baggrund af den slags invitationer giver sig til...... at rode op i det hverdagsliv, der udspiller omkring, for eksempel, skraldespande og baderum. Hvad sker der, spørger vi, når kulturanalysen kommer i vælten? Gennem de to eksempler viser vi, at vanskeligheden består i at balancere ønsket om forandring med en respekt for de seje strukturer og grundlæggende...

  20. Structure of the breakpoint region on current-voltage characteristics of intrinsic Josephson junctions

    Science.gov (United States)

    Shukrinov, Yu. M.; Mahfouzi, F.; Suzuki, M.

    2008-10-01

    A fine structure of the breakpoint region in the current-voltage characteristics of the coupled intrinsic Josephson junctions in the layered superconductors is found. We establish a correspondence between the features in the current-voltage characteristics and the character of the charge oscillations in superconducting layers in the stack and explain the origin of the breakpoint region structure.

  1. Current-voltage characteristics simulation and analysis of 4H-SiC metal-semiconductor-metal ultraviolet photodetectors

    Institute of Scientific and Technical Information of China (English)

    Junqin Zhang; Yintang Yang; Lifei Lou; Yan Zhao

    2008-01-01

    The current-voltage (I-V) characteristics of 4H-SiC metal-semiconductor-metal (MSM) ultraviolet pho-todetector with different finger widths and spacings, different carrier concentrations and thicknesses of n-type epitaxial layer are simulated. The simulation results indicate that the dark current and the pho-tocurrent both increase when the finger width increases. But the effect of finger width on the dark current is more significant. On the other hand, the effect of finger spacing on the photocurrent is more significant. When the finger spacing increases, the photocurrent decreases and the dark current is almost changeless. In addition, it is found that the smaller the carrier concentration of n-type epitaxial layer is, the smaller the dark current and the larger the photocurrent wiU be. It is also found that I-V characteristics of MSM detector also depend on the epitaxial layer thickness. The dark current of detector is smaller and the photocurrent is larger when the epitaxial layer thickness is about 3 μm.

  2. Temperature-dependent current-voltage characteristics of niobium SNIS Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Lacquaniti, V; Andreone, D; Cassiago, C; De Leo, N; Fretto, M; Sosso, A [National Institute of Metrological Research, Electromagnetism Division, Strada delle Cacce 91, 10135 Torino (Italy); Belogolovskii, M, E-mail: v.lacquaniti@inrim.i [Donetsk Physical and Technical Institute, National Academy of Sciences of Ukraine, Str. Rosa Luxemburg. 72, 83114 Donetsk (Ukraine)

    2010-06-01

    Motivated by a search for a suitable technology to fabricate Josephson junctions with a tunable damping regime, we performed a systematic study of the temperature effect on the critical current in Nb/Al-AlO{sub x}-Nb heterostructures with a nanometer-thick Al interlayer. For Al layer thicknesses ranging from 40 to 110 nm, we have observed a transition from hysteretic (below 4.2 K) to non-hysteretic (above 4.2 K) current-voltage curves. Measured supercurrent-vs-temperature characteristics which significantly differ from those of traditional SIS and SNS devices are interpreted in terms of the superconducting proximity effect between Al and Nb films. Thermal stability and good reproducibility of our junctions are demonstrated.

  3. 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.

  4. Resistance switching memory operation using the bistability in current-voltage characteristics of GaN/AlN resonant tunneling diodes

    Science.gov (United States)

    Nagase, Masanori; Takahashi, Tokio; Shimizu, Mitsuaki

    2016-10-01

    Resistance switching memory operations using the bistability in the current-voltage (I-V) characteristics of GaN/AlN resonant tunneling diodes (RTDs) were investigated to realize an ultrafast nonvolatile memory operating at a picosecond time scale. Resistance switching memory operations based on electron accumulation due to intersubband transitions and electron release due to tunneling current were demonstrated with high reproducibility at room temperature when the leakage of electrons accumulating in the quantum well from the deep level in the AlN barrier was suppressed. A nonvolatile memory for the processor core in a normally off computing system is expected to be realized using the bistability in the I-V characteristics of GaN/AlN RTDs.

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

    Science.gov (United States)

    Kundu, Ananya; Das, Subrat Kumar; Agarwal, Anees Bano Pooja; Pradhan, Subrata

    2016-05-01

    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.

  6. Quantitative measurements and modeling of electronic and atomic surface structure in epitaxial LaNiO3 thin films by ARPES, LEED-I(V), and DFT +DMFT

    Science.gov (United States)

    Ruf, Jacob; Nowadnick, Elizabeth; Park, Hyowon; King, Philip; Millis, Andrew; Schlom, Darrell; Shen, Kyle

    Careful exploration of the phase space available for artificially engineering emergent electronic properties in epitaxial thin films and superlattices of transition-metal oxides requires close feedback between materials synthesis, experimental characterization of both electronic and atomic structures, and modeling based on advanced computational methods. Here we apply this general strategy to the perovskite rare-earth nickelate LaNiO3, using molecular-beam epitaxy to synthesize thin films, performing in situangle-resolved photoemission spectroscopy (ARPES) and low-energy electron diffraction (LEED) measurements, and comparing our results with the predictions of density functional theory plus dynamical mean-field theory (DFT +DMFT). Our study establishes LaNiO3 as a moderately correlated metal in which the quasiparticle mass enhancement can be modeled with quantitative accuracy by DFT +DMFT. Finally, in view of efforts to produce eg orbital polarization in nickelate heterostructures as a means of mimicking single-band cuprate-like physics, we discuss the extent to which our ARPES and LEED results suggest that such effects are intrinsically present at film surfaces due to the existence of polar distortions, as reported by coherent Bragg rod analysis of surface x-ray diffraction.

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

    National Research Council Canada - National Science Library

    N Hatefi Kargan

    2013-01-01

    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...

  8. Surge current capabilities and isothermal current-voltage characteristics of high-voltage 4H-SiC junction barrier Schottky rectifiers

    Science.gov (United States)

    Palmour, J. W.; Levinshtein, M. E.; Ivanov, P. A.; Zhang, Q. J.

    2015-06-01

    Isothermal forward current-voltage characteristics of high-voltage 4H-SiC junction barrier Schottky rectifiers (JBS) have been studied for the first time. Isothermal characteristics were measured with JBS having a blocking voltage of 1700 V up to a current density j  ≈  4200 A cm-2 in the temperature range 297-460 K. Quasi-isothermal current-voltage characteristics of these devices were studied with injection of minority carriers (holes) up to j  ≈  7200 A cm-2 and ambient temperatures of 297 and 460 K. The isothermal forward current-voltage characteristics make it possible to numerically calculate (for example, by an iteration procedure) the overheating in an arbitrary operation mode.

  9. Observation of step structures in the I-V characteristics of YBCO thin films

    Science.gov (United States)

    Azoulay, J.; Verdyan, A.; Lapsker, I.

    1997-08-01

    Many electrical properties of the high Tc superconductors are widely probed utilizing current-voltage characteristics because of its sensitivity to the phase transition. In this work we report on detailed study of YBCO I-V characteristics shape above the critical current in the phase transition vicinity. For a given temperature controlled to a better than 10mK stability over the whole I-V cycle, the applied current has been gradually increased to exceed the critical current. The system has thus been driven to cross over to the mixed state. Using dI/dV versus V plots, it is shown that all the curves are characterized by a fine step structures at current densities higher than the critical ones.

  10. 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.

  11. First-Principles Electronic Structure Studies of the Current-Voltage Characteristics of Molecular Nanostructures

    Science.gov (United States)

    Pati, Ranjit; Karna, Shashi P.

    2001-03-01

    Recent advancements in the experimental measurement of conductance across a single molecule(M. A. Reed et al, Science, 278) , 252 (1997). have generated great deal of interest in the feasibility of molecular electronic devices. A successful realization of molecule based electronic devices rests on a detailed understanding of the physical principles underlying controlled transport of electron/hole across molecular units. In order to develop such a fundamental understanding, we have investigated current-voltage characteristics of metal atom (Ag, Au) substituted 1,4-dithiobenzene within Green's function approach according to Datta and coworkers( W. Tian et al, J. Chem. Phys., 109), 2874 (1998).. Ab initio Hamiltonian matrix elements are used to construct the Green's function. The calculated conductance spectrum for the molecule with S bonded to Au atoms qualitatively agrees with the experiment^1. However, large quantitative difference between the calculated and measured conductance is noted. The Au and Ag bonded 1,4-dithiobenzene molecules exhibit marked difference in their resistance and conductance spectra. The conductance of the Ag-bonded molecule is calculated to be about 1.5 times larger than that bonded with Au.

  12. Self-assembly of the 3-aminopropyltrimethoxysilane multilayers on Si and hysteretic current-voltage characteristics

    Science.gov (United States)

    Chauhan, A. K.; Aswal, D. K.; Koiry, S. P.; Gupta, S. K.; Yakhmi, J. V.; Sürgers, C.; Guerin, D.; Lenfant, S.; Vuillaume, D.

    2008-03-01

    We report the deposition of 3-aminopropyltrimethoxysilane (APTMS) multilayers on SiOx/Si(p++) substrates by a layer-by-layer self-assembly process. The multilayers were grafted in a glove box having nitrogen ambient with both humidity and oxygen contents water contact angle, ellipsometry, X-rayphotoelectron spectroscopy and atomic force microscope measurements revealed that self-assembling of the multilayers takes place in two distinct stages: (i) the first APTMS monolayer chemisorbs on a hydroxylated oxide surface by a silanization process and, (ii) the surface amino group of the first monolayer chemisorbs the hydrolyzed silane group of other APTMS molecules present in the solution, leading to the formation of a bilayer. The second stage is a self-replicating process that results in the layer-by-layer self-assembly of the multilayers with trapped NH3 + ions. The current-voltage characteristics of the multilayers exhibit a hysteresis effect along with a negative differential resistance, suggesting their potential application in the molecular memory devices. A possible mechanism for the observed hysteresis effect based on filling and de-filling of the NH3 + acting as traps is presented.

  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. On Calculating the Current-Voltage Characteristic of Multi-Diode Models for Organic Solar Cells

    CERN Document Server

    Roberts, Ken

    2016-01-01

    We provide an alternative formulation of the exact calculation of the current-voltage characteristic of solar cells which have been modeled with a lumped parameters equivalent circuit with one or two diodes. Such models, for instance, are suitable for describing organic solar cells whose current-voltage characteristic curve has an inflection point, also known as an S-shaped anomaly. Our formulation avoids the risk of numerical overflow in the calculation. It is suitable for implementation in Fortran, C or on micro-controllers.

  15. Phase-field modeling of switchable diode-like current-voltage characteristics in ferroelectric BaTiO{sub 3}

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Y., E-mail: yxc238@psu.edu; Randall, C. A.; Chen, L. Q. [Department of Materials Science and Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Shen, J. [Department of Mathematics, Purdue University, West Lafayette, Indiana 47907 (United States)

    2014-05-05

    A self-consistent model has been proposed to study the switchable current-voltage (I-V) characteristics in Cu/BaTiO{sub 3}/Cu sandwiched structure combining the phase-field model of ferroelectric domains and diffusion equations for ionic/electronic transport. The electrochemical transport equations and Ginzburg-Landau equations are solved using the Chebyshev collocation algorithm. We considered a single parallel plate capacitor configuration which consists of a single layer BaTiO{sub 3} containing a single tetragonal domain orientated normal to the plate electrodes (Cu) and is subject to a sweep of ac bias from −1.0 to 1.0 V at 25 °C. Our simulation clearly shows rectifying I-V response with rectification ratios amount to 10{sup 2}. The diode characteristics are switchable with an even larger rectification ratio after the polarization direction is flipped. The effects of interfacial polarization charge, dopant concentration, and dielectric constant on current responses were investigated. The switchable I-V behavior is attributed to the polarization bound charges that modulate the bulk conduction.

  16. 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.

  17. Kunstig belysning i væksthuse

    DEFF Research Database (Denmark)

    Traberg-Borup, Steen

    Planteproduktion i væksthusgartnerier er i dele af året betinget af kunstig belysning. I publikationen beskrives lysmåleudstyr, terminologier og enheder, omregningsfaktorer mellem enheder, lysfordeling, ophængningshøjde og afstand mellem armaturer, isoluxdiagrammer samt iso-PAR diagrammer med dat...

  18. Energistyring i væksthusgartnerier

    DEFF Research Database (Denmark)

    Strøm, J.S.(red.)

    Meddelelsen indeholder indlæg fra et gartneriteknisk seminar afholdt med det formål at belyse hvordan de energistyringsmetoder, der bruges i andre erhverv, kan tilpasses forholdene i væksthusgartnerier. Hovedvægten er lagt på oliefyrede varmeanlæg, på metoder til energimålinger og på metoder til ...

  19. 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

  20. Current-voltage characteristics of Pb and Sn granular superconducting nanowires

    DEFF Research Database (Denmark)

    Michotte, S.; Mátéfi-Tempfli, Stefan; Piraux, L.

    2003-01-01

    Current-voltage characteristics of Pb and Sn granular superconducting nanowires were investigated. The nanowires were prepared by electrodeposition in nanoporous membranes. It was observed that phase-slip-centers were formed far below the critical temperature when dc current was introduced inside...

  1. ELASTIC-SCATTERING AND THE CURRENT-VOLTAGE CHARACTERISTICS OF SUPERCONDUCTING NB-INAS-NB JUNCTIONS

    NARCIS (Netherlands)

    VANDERPOST, N; NITTA, J; TAKAYANAGI, H

    1993-01-01

    Superconducting niobium contacts are attached to a 0.8-mum-long epitaxially grown InAs channel sandwiched between insulating InGaAs layers. The current-voltage characteristics show nonlinearities at submultiples of the superconducting energy gap indicative of multiple-Andreev reflections. We demonst

  2. 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.

  3. 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 barri...

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

    CERN Document Server

    Stoyanov, Dimitar 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 got.

  5. Current-voltage characteristics of Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+x}/Ag multifilamentary tapes in zero applied magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Crisan, A. [Institute of Cryogenics, University of Southampton, Southampton (United Kingdom); Institute of Physics and Technology of Materials, Bucharest (Romania); Miu, L.; Popa, S. [Institute of Physics and Technology of Materials, Bucharest (Romania); Yang, Y.; Beduz, C. [Institute of Cryogenics, University of Southampton, Southampton (United Kingdom)

    1997-05-01

    Current-voltage characteristics of multifilamentary Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10+x}/Ag tapes (short samples) produced by the 'powder in tube' technique were measured at different temperatures close to the mean-field critical temperature, and inzero applied magnetic field. After performing the required corrections due to the current flowing in the silver matrix, the I-V curves were interpreted in terms of current-induced unbinding of the thermally created vortex-antivortex pairs. Two possible mechanisms for appearance of a finite critical current in zero applied magnetic field are discussed: the Jensen-Minnhagen quasi-two-dimensional (2D) approach, that takes into account the interlayer Josephson coupling, and a model of size limitation of vortex fluctuations. From our analysis, it seems that the latter model is more suitable for this kind of superconducting material, due probably to an accentuated intrinsic anisotropy. (author)

  6. Dispersion effect on the current voltage characteristic of AlGaN/GaN high electron mobility transistors

    Institute of Scientific and Technical Information of China (English)

    Pu Yan; Pang Lei; Chen Xiao-Juan; Yuan Ting-Ting; Luo Wei-Jun; Liu Xin-Yu

    2011-01-01

    The current voltage (IV) characteristics are greatly influenced by the dispersion effects in AlGaN/GaN highelectron mobility transistors. The direct current (DC) IV and pulsed IV measurements are performed to give a deep investigation into the dispersion effects,which are mainly related to the trap and self-heating mechanisms. The results show that traps play an important role in the kink effects,and high stress can introduce more traps and defects in the device. With the help of the pulsed IV measurements,the trapping effects and self-heating effects can be separated.The impact of time constants on the dispersion effects is also discussed. In order to achieve an accurate static DC IV measurement,the steady state of the bias points must be considered carefully to avoid the dispersion effects.

  7. Double threshold behaviour of I-V characteristics of CoSi2/Si Schottky contacts

    Institute of Scientific and Technical Information of China (English)

    Zhu Shi-Yang(竺士炀); Ru Guo-Ping(茹国平); Qu Xin-Ping(屈新萍); Li Bing-Zong(李炳宗); R.L.Van Meirhaeghe; C.Detavernier; F.Cardon

    2002-01-01

    The forward current-voltage (I-V) characteristics of polycrystalline CoSi2/n-Si(100) Schottky contacts have beenmeasured in a wide temperature range. At low temperatures (≤200K), a plateau-like section is observed in the I-Vmodel based on thermionic emission (TE) and a Gaussian distribution of Schottky barrier height (SBH). Such a doublethreshold behaviour can be explained by the barrier height inhomogeneity, i.e. at low temperatures the current throughpatches with low SBH dominates at small bias region With increasing bias voltage, the Ohmic effect becomes someimportant and the current through the whole junction area exc eeds the patch current, thus resulting in a plateau-likesection in the I-V curves at moderate bias. For the polycrystalline CoSi2/Si contacts studied in this paper, the apparentideality factor of the patch current is much larger than that calculated from the TE model taking the pinch-off effectinto account. This suggests that the current flowing through these patches is of the tunnelling type, rather than thethermionic emission type. The experimental I-V characteristics can be fitted reasonably well in the whole temperatureregion using the model based on tunnelling and pinch-off.

  8. NONLINEAR CURRENT-VOLTAGE CHARACTERISTICS OF CONDUCTIVE POLYETHYLENE COMPOSITES WITH CARBON BLACK FILLED PET MICROFIBRILS

    Institute of Scientific and Technical Information of China (English)

    Qian-ying Chen; Jing Gao; Kun Dai; Huan Pang; Jia-zhuang Xu; Jian-hua Tang; Zhong-ming Li

    2013-01-01

    Current-voltage electrical behavior of in situ microfibrillar carbon black (CB)/poly(ethylene terephthalate)(PET)/polyethylene (PE) (m-CB/PET/PE) composites with various CB concentrations at ambient temperatures was studied under a direct-current electric field.The current-voltage (Ⅰ-Ⅴ) curves exhibited nonlinearity beyond a critical value of voltage.The dynamic random resistor network (DRRN) model was adopted to semi-qualitatively explain the nonlinear conduction behavior of m-CB/PET/PE composites.Macroscopic nonlinearity originated from the interracial interactions between CB/PET micro fibrils and additional conduction channels.Combined with the special conductive networks,an illustration was proposed to interpret the nonlinear Ⅰ-Ⅴ characteristics by a field emission or tunneling mechanism between CB particles in the CB/PET microfibers intersections.

  9. Effects of hydrogen bonding on current-voltage characteristics of molecular junctions

    Science.gov (United States)

    Kula, Mathias; Jiang, Jun; Lu, Wei; Luo, Yi

    2006-11-01

    We present a first-principles study of hydrogen bonding effect on current-voltage characteristics of molecular junctions. Three model charge-transfer molecules, 2'-amino-4,4'-di(ethynylphenyl)-1-benzenethiolate (DEPBT-D), 4,4'-di(ethynylphenyl)-2'-nitro-1-benzenethiolate (DEPBT-A), and 2'-amino-4,4'-di(ethynylphenyl)-5'-nitro-1-benzenethiolate (DEPBT-DA), have been examined and compared with the corresponding hydrogen bonded complexes formed with different water molecules. Large differences in current-voltage characteristics are observed for DEPBT-D and DEPBT-A molecules with or without hydrogen bonded waters, while relatively small differences are found for DEPBT-DA. It is predicted that the presence of water clusters can drastically reduce the conductivities of the charge-transfer molecules. The underlying microscopic mechanism has been discussed.

  10. The Current-voltage Characteristics Simulation of the Betavoltaic Power Supply

    Directory of Open Access Journals (Sweden)

    S.U. Urchuk

    2015-12-01

    Full Text Available In order to optimize betavoltaic power supply it was calculated the current-voltage characteristics when changing the depth of the upper p-layer and at changing doping levels structure areas. It is shown that an increase in the depth reduces the short-circuit current and thus reduces the open circuit voltage. It has been observed that the concentration of the lightly doped region more significantly influence on the current-voltage characteristics than the depth of the p-n-junction. The concentration of the n-region, equal to 1014 cm – 3, can be considered as during betavoltaic power supply design. It is shown that, by increasing the power supply activity the conversion efficiency of the structure increases, too.

  11. Closed-form expression for the current/ voltage characteristics of pin solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Taretto, K.; Rau, U.; Werner, J.H. [Institut fuer Physikalische Elektronik, Pfaffenwaldring 47, 70569, Stuttgart (Germany)

    2003-12-01

    A closed-form expression for the current-voltage relationship of pin diodes and pin solar cells is obtained. The model considers drift and diffusion currents, and assumes a uniform electric field in the intrinsic layer, equal diffusion lengths for electrons and holes and a homogeneous generation rate. We show that both drift and diffusion currents must be taken into account to describe the current over a wide range of applied voltage. The inclusion of both transport mechanisms results in diode ideality factors between 1.8 at low, and 1.2 at high applied voltages. Comparisons of current/voltage characteristics and solar cell output parameters obtained from our model with experimental data of thin-film silicon solar cells show that our model accurately explains the output characteristics of pin solar cells. (orig.)

  12. Master Equation Approach to Current-Voltage Characteristics of Solar Cells

    Science.gov (United States)

    Oh, Sangchul; Zhang, Yiteng; Alharbi, Fahhad; Kais, Sabre

    2015-03-01

    The current-voltage characteristics of solar cells is obtained using quantum master equations for electrons, holes, and excitons, in which generation, recombination, and transport processes are taken into account. As a first example, we simulate a photocell with a molecular aggregate donor to investigate whether a delocalized quantum state could enhance the efficiency. As a second example, we calculate the current-voltage characteristics of conventional p-n junction solar cells and perovskite solar cells using the master equation. The connection between the drift-diffusion model and the master equation method is established. The short-circuit current and the open-circuit voltage are calculated numerically as a function of the intensity of the sunlight and material properties such as energy gaps, diffusion constants, etc.

  13. Analytical form of current-voltage characteristic of cylindrical and spherical ionization chambers

    CERN Document Server

    Stoyanov, Dimitar G

    2007-01-01

    The basic processes of ionization and recombination of gas-filled ionization chamber are presented in this article. A differential equation describing the distribution of current densities in the volume of the ionization chamber is obtained from the balance of the particles and charges densities. As a result of the differential equation solving an analytical form of the current-voltage characteristic of cylindrical and spherical ionization chambers is got.

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

    Science.gov (United States)

    Ekdahl, Carl

    2016-06-01

    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.

  15. Investigations on the electrical current-voltage response in protein light receptors

    CERN Document Server

    Alfinito, E; Reggiani, L

    2014-01-01

    We report a theoretical/computational approach for modeling the current-voltage characteristics of sensing proteins. The modeling is applied to a couple of transmembrane proteins, bacteriorhodopsin and proteorhodopsin, sensitive to visible light and promising biomaterials for the development of a new generation of photo-transducers. The agreement between theory and experiments sheds new light on the microscopic interpretation of charge transfer in proteins and biological materials in general.

  16. Simulation of a perfect CVD diamond Schottky diode steep forward current-voltage characteristic

    Science.gov (United States)

    Kukushkin, V. A.

    2016-10-01

    The kinetic equation approach to the simulation of the perfect CVD diamond Schottky diode current-voltage characteristic is considered. In result it is shown that the latter has a significantly steeper forward branch than that of perfect devices of such a type on usual semiconductors. It means that CVD diamond-based Schottky diodes have an important potential advantage over analogous devices on conventional materials.

  17. Effect of Bias Step on the I-V Curve in Double-Barrier AlGaAs/GaAs/AlGaAs Resonant-Tunnelling Devices

    Institute of Scientific and Technical Information of China (English)

    DAI Zhen-Hong; NI Jun

    2006-01-01

    @@ We investigate the non-equilibrium electron transport properties of double-barrier AlGaAs/GaAs/AlGaAs resonanttunnelling devices in nonlinear bias using the time-dependent simulation technique. It is found that the bias step of the external bias voltage applied on the device has an important effect on the final current-voltage (I - V) curves. The results show that different bias step applied on the device can change the bistability, hysteresis and current plateau structure of the I - V curve. The current plateau occurs only in the case of small bias step. As the bias step increases, this plateau structure disappears.

  18. Studies on temperature dependence of current-voltage characteristics of glancing angle deposited indium oxide nanowire on silicon substrate

    Energy Technology Data Exchange (ETDEWEB)

    Mondal, Aniruddha, E-mail: aniruddhamo@gmail.com; Das, Amit Kumar [Department of Physics, National Institute of technology Durgapur, Mahatma Gandhi Rd, A-Zone, Durgapur, West Bengal, India-713209 (India); Dey, Anubhab [Indian Institute of Science Education and Research, Thiruvananthapuram, Computer Science Building, College of Engineering Trivandrum Campus, Thiruvananthapuram, Kerala 695016 (India); Choudhuri, Bijit [Department of Electronics & Communication Engineering, National Institute of Technology Agartala, Jirania, Tripura, India - 799046 (India)

    2016-05-06

    The 1D perpendicular In{sub 2-x}O{sub 3-y} nanostructure arrays have been synthesized by using glancing angle deposition (GLAD) technique. A low deposition rate of 0.5 A°/S produced highly porous structure. The current - voltage characteristics for the In{sub 2-x}O{sub 3-y}nanocolumnar array based were measured through a gold Schottky contact at different temperatures. The temperature dependent ideality factor was calculated from the observed current – voltage characteristics. The ideality factor was found to vary from 4.19 to 2.75 with a variation in temperature from 313 K to 473 K.

  19. Interpretation of current-voltage relationships for "active" ion transport systems: I. Steady-state reaction-kinetic analysis of class-I mechanisms.

    Science.gov (United States)

    Hansen, U P; Gradmann, D; Sanders, D; Slayman, C L

    1981-01-01

    This paper develops a simple reaction-kinetic model to describe electrogenic pumping and co- (or counter-) transport of ions. It uses the standard steady-state approach for cyclic enzyme- or carrier-mediated transport, but does not assume rate-limitation by any particular reaction step. Voltage-dependence is introduced, after the suggestion of Läuger and Stark (Biochim. Biophys. Acta 211:458-466, 1970), via a symmetric Eyring barrier, in which the charge-transit reaction constants are written as k12 = ko12 exp(zF delta psi/2RT) and k21 = ko21 exp(-zF delta psi/2RT). For interpretation of current-voltage relationships, all voltage-independent reaction steps are lumped together, so the model in its simplest form can be described as a pseudo-2-state model. It is characterized by the two voltage-dependent reaction constants, two lumped voltage-independent reaction constants (k12, k21), and two reserve factors (ri, ro) which formally take account of carrier states that are indistinguishable in the current-voltage (I-V) analysis. The model generates a wide range of I-V relationships, depending on the relative magnitudes of the four reaction constants, sufficient to describe essentially all I-V datas now available on "active" ion-transport systems. Algebraic and numerical analysis of the reserve factors, by means of expanded pseudo-3-, 4-, and 5-state models, shows them to be bounded and not large for most combinations of reaction constants in the lumped pathway. The most important exception to this rule occurs when carrier decharging immediately follows charge transit of the membrane and is very fast relative to other constituent voltage-independent reactions. Such a circumstance generates kinetic equivalence of chemical and electrical gradients, thus providing a consistent definition of ion-motive forces (e.g., proton-motive force, PMF). With appropriate restrictions, it also yields both linear and log-linear relationships between net transport velocity and either

  20. Nonlinear current-voltage characteristics of sintered tungsten-vanadium oxide

    Institute of Scientific and Technical Information of China (English)

    Liu Zu-Li; Yang Lin-Feng; Wang Yu; Yao Kai-Lun; Wang Chuan-Cong

    2004-01-01

    We have studied the densification behaviour, microstructure and electrical properties of WO3 ceramics with V2O5as the additive ranging from 0.5 to 15mo1%. Scanning electron microscopic photos indicated that the grain size of WO3-V2O5 specimens is smaller than that of pure WO3. The addition of V2O5 to WO3 showed a tendency to enhance the densification rate and to restrict the grain growth. Electrical properties of all specimens were measured for different electrodes at different temperatures. The formation of the grain boundary barrier layer was confirmed by the non-ohmic I-V behaviour. The nonlinear coefficient was obtained at the current density J=0.01, 0.1 and 1mA-cm2 for a series of WO3-V2O5 samples. The V0.Smol% specimen showed an abnormal phenomenon that the nonlinear characteristics appeared at 350℃ and disappeared at lower and higher temperatures. This implies that it could be applied as a hightemperature varistor. The double Schottky barrier model was adopted to explain the phenomena for the WO3-V2O5varistors.

  1. Current voltage characteristics of intrinsic Josephson junctions with charge-imbalance effect

    Science.gov (United States)

    Shukrinov, Yu. M.; Mahfouzi, F.

    2007-09-01

    The current-voltage characteristics (IVC) of intrinsic Josephson junctions are numerically calculated taking into account the quasiparticle charge-imbalance effect. We solve numerically the full set of the equations including second order differential equations for phase differences, kinetic equations and generalized Josephson relations for a stack of Josephson junctions. The boundary conditions due to the proximity effect are used. We obtain the branch structure of IVC and investigate it as a function of disequilibrium parameter at different values of coupling constant and McCumber parameter. An increase in the disequilibrium parameter essentially changes the character of IVC at large values of McCumber parameter.

  2. The influence of microwave irradiation power on current voltage characteristics of intrinsic Josephson junctions

    Science.gov (United States)

    Shukrinov, Yu M.; Mans, M.; Scherbel, J.; Seidel, P.

    2007-02-01

    The current-voltage characteristics of a micrometre bridge of intrinsic Josephson junctions under microwave irradiation are studied. The collective switching of the group of four junctions splits up as the AC signal amplitude is gradually increased. The switching current of the remaining group of junctions is increased with increasing radiation power. We consider that microwave irradiation injects an additional quasiparticle current into the Josephson junction array. We use ideas of breakdown of quasineutrality and quasiparticle charge imbalance in the superconducting layers and explain the experimental results by the competition between the 'current effect' and the effect of suppression of the switching current by irradiation.

  3. Current-voltage characteristics of intrinsic Josephson junctions with charge-imbalance effect

    Energy Technology Data Exchange (ETDEWEB)

    Shukrinov, Yu.M. [Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Physical Technical Institute, Dushanbe 734063 (Tajikistan)], E-mail: shukrinv@theor.jinr.ru; Mahfouzi, F. [Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Zanjan (Iran, Islamic Republic of)

    2007-09-01

    The current-voltage characteristics (IVC) of intrinsic Josephson junctions are numerically calculated taking into account the quasiparticle charge-imbalance effect. We solve numerically the full set of the equations including second order differential equations for phase differences, kinetic equations and generalized Josephson relations for a stack of Josephson junctions. The boundary conditions due to the proximity effect are used. We obtain the branch structure of IVC and investigate it as a function of disequilibrium parameter at different values of coupling constant and McCumber parameter. An increase in the disequilibrium parameter essentially changes the character of IVC at large values of McCumber parameter.

  4. The influence of microwave irradiation power on current-voltage characteristics of intrinsic Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Shukrinov, Yu M [BLTP, JINR, Dubna, Moscow Region, 141980 (Russian Federation); Mans, M [Institut fur Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, D-07743 Jena (Germany); Scherbel, J [Institut fur Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, D-07743 Jena (Germany); Seidel, P [Institut fur Festkoerperphysik, Friedrich-Schiller-Universitaet Jena, D-07743 Jena (Germany)

    2007-02-15

    The current-voltage characteristics of a micrometre bridge of intrinsic Josephson junctions under microwave irradiation are studied. The collective switching of the group of four junctions splits up as the AC signal amplitude is gradually increased. The switching current of the remaining group of junctions is increased with increasing radiation power. We consider that microwave irradiation injects an additional quasiparticle current into the Josephson junction array. We use ideas of breakdown of quasineutrality and quasiparticle charge imbalance in the superconducting layers and explain the experimental results by the competition between the 'current effect' and the effect of suppression of the switching current by irradiation.

  5. Modeling And Simulation of Speed and flux Estimator Based on Current & voltage Model

    Directory of Open Access Journals (Sweden)

    Dinesh Chandra Jain

    2011-10-01

    Full Text Available This paper introduce a estimator based on and current & voltage model used in induction motor (IM drive. The rotor speed estimation is based on the model reference adaptive system (MRAS approach. The closed loop control mechanism is based on the voltage and current model. The control and estimation algorithms utilize the synchronous coordinates as a frame of reference. A speed sensor less induction motor (IM drive with Robust control characteristics is introduced. First, a speed observation system, which is insensitive to the variations of motor parameters.

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen Zuhui [Lee-Kuan-Yew Postdoctoral Fellow, 2007-2010, Nanyang Technological University, Singapore 639798 (Singapore); Jie Binbin; Sah Chihtang, E-mail: bb_jie@msn.com [Department of Physics, Xiamen University, Xiamen 361005 (China)

    2010-12-15

    Impurity deionization on the direct-current current-voltage characteristics from electron-hole recombination (R-DCIV) at SiO{sub 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)

  7. Effect of spontaneous polarization change on current-voltage characteristics of thin ferroelectric films

    Science.gov (United States)

    Podgorny, Yu. V.; Lavrov, P. P.; Vorotilov, K. A.; Sigov, A. S.

    2015-03-01

    The role of a change in the spontaneous polarization charge in the formation of negative differential conductance regions of the current-voltage characteristics of thin ferroelectric films has been determined. It has been shown that the polarization recovery current, which appears due to partial depolarization of a preliminarily polarized film, prevails over the intrinsic leakage current of the ferroelectric film in the coercive field region and corresponds to the Weibull distribution. The influence of polarization recovery current decreases with decreasing voltage sweep rate.

  8. Comment on "Electrical Conductivity and Current-Voltage Characteristics of Individual Conducting Polymer PEDOT Nanowires"

    Institute of Scientific and Technical Information of China (English)

    P. Ohlckers; P. Pipinys

    2009-01-01

    @@ In "Electrical Conductivity and Current-Voltage Characteristics of Individual Conducting Polymer PEDOT Nanowires", Long et al.[1] reported the currentvoltage ( Ⅰ - Ⅴ) characteristics of individual poly(3,4-ethylenedioxythiophene) (PEDOT) nanowires in the temperature range from 20 to 50K (Fig. 2(a)). The authors stated that at temperatures equal to 50 K and higher, the Ⅰ - Ⅴ curves were linear. With decreasing temperature the Ⅰ - Ⅴ curves gradually became nonlinear. The temperature behavior of Ⅰ - Ⅴ characteristics is not suitably explained.

  9. Current-voltage characteristics of an individual helical CdS nanowire rope

    Institute of Scientific and Technical Information of China (English)

    Long Yun-Ze; Wang Wen-Long; Bai Feng-Lian; Chen Zhao-Jia; Jin Ai-Zi; Gu Chang-Zhi

    2008-01-01

    This paper studies the electronic transport in an individual helically twisted CdS nanowire rope, on which platinum microleacls are attached by focused-ion beam deposition. The current-voltage (Ⅰ - Ⅴ ) characteristics are nonlinear from 300 down to 60 K. Some step-like structures in the Ⅰ - Ⅴ curves and oscillation peaks in the differential conductance (dⅠ/dⅤ - Ⅴ) curves have been observed even at room temperature. It proposes that the observed behaviour can be attributed to Coulomb-blockade transport in the one-dimensional CdS nanowires with diameters of 6-10 nm.

  10. Analytical two-dimensional model of solar cell current-voltage characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Caldararu, F.; Caldararu, M.; Nan, S.; Nicolaescu, D.; Vasile, S. (ICCE, Bucharest (RO). R and D Center for Electron Devices)

    1991-06-01

    This paper describes an analytical two-dimensional model for pn junction solar cell I-V characteristic. In order to solve the two-dimensional equations for the minority carrier concentration the Laplace transformation method is used. The model eliminates Hovel's assumptions concerning a one-dimensional model and provides an I-V characteristic that is simpler than those derived from the one-dimensional model. The method can be extended to any other device with two-dimensional symmetry. (author).

  11. 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

    ) was clamped to zero and step-changes of Na activity in the outer solution ((Na)(o)) were performed with a fast-flow chamber at constant ionic strength, while the short-circuit current was recorded.3. At pre-selected times after a step-change of (Na)(o) the current response (I) to a fast voltage staircase...... 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...... transport through open Na-selective channels of the outward facing membrane of the stratum granulosum cells can be described as an electrodiffusion process which as such does not saturate with increasing (Na)(o). However, when added to the outer border of the membrane Na causes a decrease of P(Na) within...

  12. Influence of coupling parameter on current-voltage characteristics of intrinsic Josephson junctions in high-T {sub c} superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Shukrinov, Yu.M. [BLTP, JINR, Moscow Region, Dubna 141980 (Russian Federation) and Physical Technical Institute, Dushanbe 734063 (Tajikistan)]. E-mail: shukrinv@theor.jinr.ru; Mahfouzi, F. [Institute for Advanced Studies in Basic Sciences, P.O. Box 45195-1159, Zanjan (Iran, Islamic Republic of)

    2006-02-01

    We study the current-voltage characteristics of intrinsic Josephson junctions in high-T {sub 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 {alpha} on the current-voltage characteristics at fixed parameter {beta} ({beta} {sup 2} 1/{beta} {sub c}, where {beta} {sub c} is McCumber parameter) and the influence of {alpha} on {beta}-dependence of the current-voltage characteristics are investigated. We obtain the {alpha}-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 {sub c} superconductors.

  13. Influence of coupling parameter on current-voltage characteristics of intrinsic Josephson junctions in high- Tc superconductors

    Science.gov (United States)

    Shukrinov, Yu. M.; Mahfouzi, F.

    2006-02-01

    We study the current-voltage characteristics of intrinsic Josephson junctions in high-Tc 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 (β2 = 1/βc, where βc 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-Tc superconductors.

  14. 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.

  15. 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.

  16. Current-voltage characteristics of light-emitting diodes under optical and electrical excitation

    Institute of Scientific and Technical Information of China (English)

    Wen Jing; Wen Yumei; Li Ping; Li Lian

    2011-01-01

    The factors influencing the current-voltage (Ⅰ-Ⅴ) characteristics of light-emitting diodes (LEDs) are investigated to reveal the connection of Ⅰ-Ⅴ characteristics under optical excitation and those under electrical excitation.By inspecting the Ⅰ-Ⅴ curves under optical and electrical excitation at identical injection current,it has been found that the Ⅰ-Ⅴ curves exhibit apparent differences in voltage values.Furthermore,the differences are found to originate from the junction temperatures in diverse excitation ways.Experimental results indicate that if the thermal effect of illuminating spot is depressed to an ignorable extent by using pulsed light,the junction temperature will hardly deflect from that under optical excitation,and then the Ⅰ-Ⅴ characteristics under two diverse excitation ways will be the same.

  17. Current voltage analysis and band diagram of Ti/TiO{sub 2} nanotubes Schottky junction

    Energy Technology Data Exchange (ETDEWEB)

    Mini, P.A.; Sherine, Alex; Shalumon, K.T.; Balakrishnan, Avinash; Nair, S.V.; Subramanian, K.R.V. [Amrita Vishwa Vidyapeetham (University), Amrita Centre for Nanosciences and Molecular Medicine, Kochi (India)

    2012-08-15

    Here, we report on how the energy band diagram of a nanostructured semiconductor- metal interface aligns in accordance with semiconductor morphology. Electrochemically, titanium metal is anodized to form titanium dioxide nanotubes, which forms a junction with the free Ti substrate and this junction forms a natural Schottky barrier. With reduced dimensionality of the nanotube structures (lower wall thickness), we have observed band edge movements and band gap quantum confinement effects and lowering of the Schottky barrier. These results were corroborated with the help of cyclic voltammetry, ultraviolet-visible spectrometry, and impedance analysis. Current voltage analysis of the Schottky barrier showed a lowering of the barrier (by 25 %) with reducing dimensionality of the nanotube structures. At externally applied voltages higher than the Schottky barrier, charges can travel along the nanotubes and reside at an interface between the nanotubes and a high-{kappa} dielectric. This property was utilized to develop high surface area solid-state capacitors. (orig.)

  18. Current voltage analysis and band diagram of Ti/TiO2 nanotubes Schottky junction

    Science.gov (United States)

    Mini, P. A.; Sherine, Alex; Shalumon, K. T.; Balakrishnan, Avinash; Nair, S. V.; Subramanian, K. R. V.

    2012-08-01

    Here, we report on how the energy band diagram of a nanostructured semiconductor- metal interface aligns in accordance with semiconductor morphology. Electrochemically, titanium metal is anodized to form titanium dioxide nanotubes, which forms a junction with the free Ti substrate and this junction forms a natural Schottky barrier. With reduced dimensionality of the nanotube structures (lower wall thickness), we have observed band edge movements and band gap quantum confinement effects and lowering of the Schottky barrier. These results were corroborated with the help of cyclic voltammetry, ultraviolet-visible spectrometry, and impedance analysis. Current voltage analysis of the Schottky barrier showed a lowering of the barrier (by 25 %) with reducing dimensionality of the nanotube structures. At externally applied voltages higher than the Schottky barrier, charges can travel along the nanotubes and reside at an interface between the nanotubes and a high- κ dielectric. This property was utilized to develop high surface area solid-state capacitors.

  19. Temperature current-voltage characterisation of MOCVD grown InGaN/GaN MQW LEDs

    Energy Technology Data Exchange (ETDEWEB)

    Moldovan, Grigore; Humphreys, Colin J. [Department of Materials Science and Metallurgy, University of Cambridge, Pembroke Street, Cambridge, CB2 3QZ (United Kingdom); Phillips, Andrew [phconsult Ltd., 54 Covent Garden, Cambridge, CB1 2HR (United Kingdom); Thrush, E.J. [Thomas Swan Scientific Equipment Limited, Buckingway Business Park, Cambridge, CB4 5UK (United Kingdom)

    2006-06-15

    A methodology of temperature current-voltage characterisation for blue GaN-based LED is described, with emphasis on artefacts arising from self-heating at high forward currents and voltage transients at low forward currents. Examples of LEDs with Al{sub 2}O{sub 3} and SiC substrates are discussed, with methods of accounting and avoiding these errors. For the devices studied here it is found that tunnelling dominates the charge transport and that two parallel conduction pathways are present. A method of interpretation of extracted data is also presented, in the context of desired device performance. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Improved performance of a barrier-discharge plasma jet biased by a direct-current voltage

    Science.gov (United States)

    Li, Xuechen; Li, Yaru; Zhang, Panpan; Jia, Pengying; Dong, Lifang

    2016-01-01

    One of the challenges that plasma research encounters is how to generate a large-scale plasma plume at atmospheric pressure. Through utilizing a third electrode biased by a direct-current voltage, a longer plasma plume is generated by a plasma jet in dielectric barrier discharge configurations. Results indicate that the plume length increases until it reaches the third electrode with increasing the bias voltage. By fast photography, it is found that the plume consists of two types of streamers under the influence of the bias voltage, which develops from a guided streamer to a branching one with leaving the tube opening. The transition from the guided streamer to the branching one can be attributed to the electric field and the air/argon fraction. PMID:27759080

  1. Modeling the current-voltage characteristics of bilayer polymer photovoltaic devices

    Science.gov (United States)

    Barker, J. A.; Ramsdale, C. M.; Greenham, N. C.

    2003-02-01

    We have developed a numerical model to predict the current-voltage curves of bilayer conjugated polymer photovoltaic devices. The model accounts for charge photogeneration, injection, drift, diffusion, and recombination, and includes the effect of space charge on the electric field within the device. Charge separation at the polymer-polymer interface leads to the formation of bound polaron pairs which may either recombine monomolecularly or be dissociated into free charges, and we develop expressions for the field dependence of the dissociation rate. We find that the short-circuit quantum efficiency is determined by the competition between polaron pair dissociation and recombination. The model shows a logarithmic dependence of the open-circuit voltage on the incident intensity, as seen experimentally. This additional intensity-dependent voltage arises from the field required to produce a drift current that balances the current due to diffusion of carriers away from the interface.

  2. Improved performance of a barrier-discharge plasma jet biased by a direct-current voltage

    Science.gov (United States)

    Li, Xuechen; Li, Yaru; Zhang, Panpan; Jia, Pengying; Dong, Lifang

    2016-10-01

    One of the challenges that plasma research encounters is how to generate a large-scale plasma plume at atmospheric pressure. Through utilizing a third electrode biased by a direct-current voltage, a longer plasma plume is generated by a plasma jet in dielectric barrier discharge configurations. Results indicate that the plume length increases until it reaches the third electrode with increasing the bias voltage. By fast photography, it is found that the plume consists of two types of streamers under the influence of the bias voltage, which develops from a guided streamer to a branching one with leaving the tube opening. The transition from the guided streamer to the branching one can be attributed to the electric field and the air/argon fraction.

  3. Instabilities in the current-voltage characteristics of submicron BSCCO bridges

    Energy Technology Data Exchange (ETDEWEB)

    Zybtsev, S G [Institute of Radioengineering and Electronics RAS Moscow 125009 (Russian Federation); Pokrovskii, V Ya [Institute of Radioengineering and Electronics RAS Moscow 125009 (Russian Federation); Gorlova, I G [Institute of Radioengineering and Electronics RAS Moscow 125009 (Russian Federation); Latyshev, Yu I [Institute of Radioengineering and Electronics RAS Moscow 125009 (Russian Federation); Timofeev, V N [A.A. Baikov Institute of Metallurgy RAS Moscow (Russian Federation)

    2006-06-01

    The influence of magnetic field and microwave irradiation on dynamical phase separation in submicron Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8+x} bridges has been studied. Strong effect on the shape and metastable character of the step-like I-V characteristics are found. Under a weak field H < 2 Oe and low level microwave irradiation the step-like structure of the I-V characteristics smears out and disappears completely. The average frequency of switching between metastable states grows by 5 orders under increase of magnetic field by only 1 Oe. This behavior is explained in terms of the model of dynamical vortex lines.

  4. The interface states and series resistance effects on the forward and reverse bias I-V, C-V and G/{omega}-V characteristics of Al-TiW-Pd{sub 2}Si/n-Si Schottky barrier diodes

    Energy Technology Data Exchange (ETDEWEB)

    Uslu, H.; Altindal, S.; Aydemir, U. [Department of Physics, Gazi University, 06500 Ankara (Turkey); Doekme, I., E-mail: ilbilgedokme@gazi.edu.t [Science Education Department, Gazi Education Faculty, Gazi University, 06500 Ankara (Turkey); Afandiyeva, I.M. [Baku State University, Baku (Azerbaijan)

    2010-07-30

    Illumination intensity effects on the electrical characteristics of Al-TiW-Pd{sub 2}Si/n-Si Schottky structures have been investigated in this study for the first time. The electrical parameters such as ideality factor (n), zero-bias-barrier height ({Phi}{sub B0}), series resistance (R{sub s}), depletion layer width (W{sub D}) and dopping concentration (N{sub D}) of Al-TiW-Pd{sub 2}Si/n-Si Schottky barrier diodes (SBDs) have been investigated by using the forward and reverse bias current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G/{omega}-V) measurements in dark and under illumination conditions at room temperature. The values of C and G/{omega} increase with increasing illumination intensity due to the illumination induced electron-hole pairs in the depletion region. The density of interface states (N{sub ss}) distribution profiles as a function of (E{sub c} - E{sub ss}) was extracted from the forward I-V measurements by taking into account the bias dependence of the effective barrier heights ({Phi}{sub e}) for device in dark and under various illumination intensities. The high values of N{sub ss} were responsible for the nonideal behavior of I-V, C-V and G/{omega} characteristics. The values of R{sub s} obtained from Cheung and Nicollian methods decrease with increasing illumination intensity. The high values of n and R{sub s} have been attributed to the particular distribution of N{sub ss}, surface preparation, inhomogeneity of interfacial layer and barrier height at metal/semiconductor (M/S) interface. As a result, the characteristics of SBD are affected not only in N{sub ss} but also in R{sub s}, and these two parameters strongly influence the electrical parameters.

  5. Automation Of An I-V Characterization System

    Directory of Open Access Journals (Sweden)

    J. R. Noriega

    2010-08-01

    Full Text Available In this paper, an accurate I-V virtual instrument (VI that has been developed to characterize electronic devices forresearch and teaching purposes is demonstrated. The virtual instrument can be used to highlight principles ofmeasurement, instrumentation, fundamental principles of electronics, VI programming, device testing andcharacterization in wafer or discrete device level. It consists of a Keithley electrometer, model 6514, a programmablepower supply BK Precision, model 1770, a Keithley source meter, model 2400-LV, an Agilent digital multimeter, model34401, a PC computer and LabVIEW software. The instruments are interconnected using an IEEE 488 protocol. Thecharacteristic VI devices graphs are generated from measured data previous computational processing. Theinstrument is used in basic courses of physical electronics as well as in advance curses of VLSI design and inresearch work for characterization of semiconductor materials and devices. This paper describes the VI instrumentdesign, implementation and characterization experiments.

  6. 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.

  7. Self-field effects on critical current density and current-voltage characteristics in superconducting YBaCuO thick films

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez, A.D.; Hart, C.; Martinez, C.M.; Ares, O. [Superconductivity Lab, IMRE-University of Havana, Vedado 10400, Havana (Cuba)

    1999-07-01

    The self-field and percolative influences on transport measurements of polycrystalline bridges engraved on YBaCuO thick film have been investigated. A maximum in the dependence of the critical current density on cross-sectional area of the bridge (A = 0.003 mm{sup 2}-0.3 mm{sup 2}) has been found experimentally, in samples with low critical current densities (J{sub c}<50 A cm{sup -2}). The result of the measurements are in agreement with Mulet and coworkers, who have predicted that, under certain conditions, the self-field effects on transport measurements are negligible and the J{sub c} dependence on the sample dimensions is determined by the percolative character of the transport current. Self-field influences have also been observed in current-voltage characteristics, which have been analysed using the Ambegaokar-Halperin phase-slip theory. By allowing the noise parameter ({gamma}) to change with temperature, magnetic field and transport current, adequate agreement between theoretical and experimental current-voltage characteristics has been obtained. The dependence of the noise parameter with the transport current is demonstrated to be related with the self-field. (author)

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

    CERN Document Server

    Stoyanov, Dimitar G

    2007-01-01

    The elementary processes taking place in the formation of charged particles and their flow in the ionization chamber are considered. On the basic 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.

  9. Lattice Ordered Structure of i-v Fuzzy Sets%i-v Fuzzy集的格序结构

    Institute of Scientific and Technical Information of China (English)

    周亚兰

    2013-01-01

    i-v Fuzzy 集上引入了顺序和运算,并证明了任一非空集 X 上的一切i-v Fuzzy 集的全体F ( X )i-v构成一完备的完全分配格,且关于引入的对合运算构成一Fuzzy格。%Order and operation are introduced into i-v Fuzzy sets. It is proved that all i-v Fuzzy sets of any nonempty sets X , F ( X )i-v composes a complete distributive lattice, and involution operation inductive composes a Fuzzy lattice.

  10. The current-voltage and noise properties of high temperature superconductor SNS and grain boundary junctions

    CERN Document Server

    McGordon, A

    1999-01-01

    transport that was dominated by the interlayer material, but supercurrent transport that could be due to pinhole shorts. In addition, both geometries, especially the sandwich junction, showed large amounts of normal state noise making these junctions unsuitable for device applications. The effect of shining laser light onto a junction was investigated. The effects on the I-V characteristic were unobservable with the experimental resolution available. The effect of the light on the critical current noise of the junction was to reduce the noise peak slightly when compared to the unilluminated case- the reduction was of the order of 10%, comparable with experimental resolution. The study of the noise from Josephson Junctions is an intense field of research. Despite this, no clear picture of the current transport in these devices has emerged. Without the detailed understanding of the mechanisms of current transport in High Temperature Superconductor junctions, the design of superconducting electronics will not mo...

  11. Asymmetry of Polarization Reversal and Current-Voltage Characteristics of Pt/PZT-Film/Pt:Ti/SiO2/Si-Substrate Structures

    Directory of Open Access Journals (Sweden)

    S. L. Bravina

    2011-01-01

    Full Text Available The characterization of the asymmetries of bipolar charge-voltage and current-voltage loops of polarization reversal and unipolar current-voltage curves for Pt/PZT-film/Pt:Ti/SiO2/Si-substrate systems was performed in the dynamic mode. The asymmetry of local deformation-voltage loops was observed by piezoresponse force microscopy. The comparison of the dependences of introduced asymmetry factors for the bipolar charge-voltage and current-voltage loops and unipolar current-voltage curves on drive voltage indicates the interconnection of ferroelectric and electrical space charge transfer asymmetries.

  12. Fabrication and current-voltage characteristics of NiOx/ZnO based MIIM tunnel diode

    Science.gov (United States)

    Singh, Aparajita; Ratnadurai, Rudraskandan; Kumar, Rajesh; Krishnan, Subramanian; Emirov, Yusuf; Bhansali, Shekhar

    2015-04-01

    Enhanced asymmetric and non-linear characteristics of Ni-NiOx based MIM diode has been reported by the addition of a second insulator layer ZnO to form MIIM configuration. These properties are required for applications like energy-harvesting devices, terahertz electronics, macro electronics, etc. In this work, single insulator layer Ni-NiOx-Cr and double insulator Ni-NiOx-ZnO-Cr tunnel diodes were fabricated and their I-V characteristics were studied. A significant increase by one order of magnitude in asymmetry has been observed in case of bilayer NiOx/ZnO dielectric configuration at low voltages. The sensitivity of the NiOx and NiOx/ZnO dielectric configuration in MIM stack was 11 V-1 and 16 V-1. The improved performance of the bilayer insulator diode is due to the second insulator which enables resonant tunneling or step-tunneling. Resonant tunneling was found to be dominant through trap assisted tunneling in the NiOx/ZnO diode.

  13. Effect of coupling on scheme of hysteresis jumps in current-voltage characteristics of intrinsic Josephson junctions in high- superconductors

    OpenAIRE

    Shukrinov, Yu M.; Mahfouzi, F.

    2005-01-01

    We report the numerical calculations of the current-voltage characteristics of intrinsic Josephson junctions in high- superconductors. The charging effect at superconducting layers is taken into account. A set of equations is used to study the non-linear dynamics of the system. In framework of capacitively coupled Josephson junctions model we obtain the total number of branches using fixed initial conditions for phases and their derivatives. The influence of the coupling constant \\alpha on th...

  14. Scaling and disorder analysis of local I-V curves from ferroelectric thin films of lead zirconate titanate.

    Science.gov (United States)

    Maksymovych, Peter; Pan, Minghu; Yu, Pu; Ramesh, Ramamoorthy; Baddorf, Arthur P; Kalinin, Sergei V

    2011-06-24

    Differential analysis of current-voltage characteristics, obtained on the surface of epitaxial films of ferroelectric lead zirconate titanate (Pb(Zr(0.2)Ti(0.8))O(3)) using scanning probe microscopy, was combined with spatially resolved mapping of variations in local conductance to differentiate between candidate mechanisms of local electronic transport and the origin of disorder. Within the assumed approximations, electron transport was inferred to be determined by two mechanisms depending on the magnitude of applied bias, with the low-bias range dominated by the trap-assisted Fowler-Nordheim tunneling through the interface and the high-bias range limited by the hopping conduction through the bulk. Phenomenological analysis of the I-V curves has further revealed that the transition between the low- and high-bias regimes is manifested both in the strength of variations within the I-V curves sampled across the surface, as well as the spatial distribution of conductance. Spatial variations were concluded to originate primarily from the heterogeneity of the interfacial electronic barrier height with an additional small contribution from random changes in the tip-contact geometry.

  15. 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.

  16. 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.

  17. A simple method of extracting the polarization charge density in the AlGaN/GaN heterostructure from current-voltage and capacitance-voltage characteristics

    Institute of Scientific and Technical Information of China (English)

    Lü Yuan-Jie; Lin Zhao-Jun; Yu Ying-Xia; Meng Ling-Guo; Cao Zhi-Fang; Luan Chong-Biao; Wang Zhan-Guo

    2012-01-01

    An Ni Schottky contact on the AlGaN/GaN heterostructure is fabricated.The flat-band voltage for the Schottky contact on the AlGaN/GaN heterostructure is obtained from the forward current-voltage characteristics.With the measured capacitance-voltage curve and the flat-band voltage,the polarization charge density in the AlGaN/GaN heterostructure is investigated,and a simple formula for calculating the polarization charge density is obtained and analyzed.With the approach described in this paper,the obtained polarization charge density agrees well with the one calculated by self-consistently solving Schrodinger's and Poisson's equations.

  18. Driver for solar cell i-v characteristic plots

    Energy Technology Data Exchange (ETDEWEB)

    Turner, G.B.

    1980-01-15

    A bipolar voltage ramp generator applies a linear voltage through a resistor to a solar cell for plotting its current versus voltage (I-v) characteristic between short circuit and open circuit conditions, with automatic stops at the end points. The resistor serves the multiple purpose of providing a current sensing resistor, setting the full-scale current value, and providing a load line with a slope approximately equal to one, such that it will pass through the origin and the approximate center of the i-v curve with about equal distance from that center to each of the end points.

  19. 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.

  20. 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...... due to cell fractures, and the additional series resistance losses observed under illumination. Based on the analysis, we propose an in-situ module power loss monitoring procedure that relies on dark current-voltage measurements taken during the stress test and initial and final module flash testing...

  1. Optimal I-V Curve Scan Time of Solar Cells and Modules in Light of Irradiance Level

    Directory of Open Access Journals (Sweden)

    Matic Herman

    2012-01-01

    Full Text Available High-efficiency solar cells and modules exhibit strong capacitive character resulting in limited speed of transient responses. A too fast I-V curve measurement can thus introduce a significant error due to its internal capacitances. This paper analyses the I-V curve error of a measured solar cell or module in light of scan time and irradiance level. It rests on a two-diode solar cell model extended by two bias-dependent capacitances, modelling the junction, and the diffusion capacitance. A method for determination of all extended model parameters from a quasistatic I-V curve and open-circuit voltage decay measurement is presented and validated. Applicability of the extended model and the developed parameter extraction method to PV modules is demonstrated and confirmed. SPICE simulations of the extended model are used to obtain the I-V curve error versus scan time dependence and the I-V curve hysteresis. Determination of the optimal scan time is addressed, and finally the influence of the irradiance level on the I-V curve scan time and error is revealed. The method is applied but is not limited to three different wafer-based silicon solar cell types.

  2. Theoretical aspects and methods of parameters identification of the electric traction system devices. method of cyclic current-voltage characteristics

    Directory of Open Access Journals (Sweden)

    T.M.Mishchenko

    2013-02-01

    Full Text Available Purpose. To define the characteristics of numerical calculations of mathematical model with one or more cyclic current voltage characteristics (CVC. This is an urgent problem, since any electric traction system device and electrified track in general, like non-linear passive or active two-terminal network in the present operating mode is described by current-voltage characteristic (CVC, which is based on the given input voltage and input current. Me-thodology. The electromagnetic process calculation in the power circuits of traction electric energy supply is the probabilistic task with solving nonlinear stochastic differential equations requiring for the development of special methods. Given the calculation difficulty, it is reasonable to perform them either by real CVC graph bypass or initially by applying its equivalent replacement with, for example, an ellipse. Findings. Numerical calculations of the mathematical model with one or more cyclic CVC can be performed by “real” CVC bypass or by "idealization" i. e. approximate replacement of real cyclic CVC. Originality. This paper presents the dynamic CVC of the DS3 and 2ES5K electric locomotives at different currents of electric locomotives. Practical value. Cyclic CVC normally and definitely can be applied in the system of electromagnetic state equations while transient state calculating in the traction system. Therefore while calculating the experimentally obtained CVC for the most “difficult and complex” (or/and the “easiest” mode is applied.

  3. Kinetics deformation of current-voltage characteristics of the varistor oxide structures due to overcharging of the localized states

    Directory of Open Access Journals (Sweden)

    Tonkoshkur A. S.

    2014-12-01

    Full Text Available Prolonged exposure of zinc oxide varistors to the electrical load leads to current-voltage characteristics (CVC deformation, which is associated with a change in the height and width of the intergranular barriers, which are main structural element of the varistors. Polarization phenomena in zinc oxide ceramics are studied in a number of works, but those are mainly limited to the study of the physics of the CVC deformation process and to determining the parameters of localized electronic states involved in this process. This paper presents the results on the simulation of the deformation of pulse CVC of a separate intergranular potential barrier at transient polarization/depolarization, associated with recharging of surface electronic states (SES, which cause this barrier. It is found that at high density of SES their degree of electron filling is small and the effect of DC voltage leads to a shift of pulse current-voltage characteristics into the region of small currents. Conversely, the low density SES are almost completely filled with electrons, and after crystallite polarization CVC is shifted to high currents. Experimental studies have confirmed the possibility of applying the discovered laws to ceramic varistor structures. The proposed model allows interpreting the «anomalous» effects (such as increase in the classification voltage and reduction of active losses power observed during the varistors accelerated aging test.

  4. Experimental Study of the Course of Threshold Current, Voltage and Electrode Impedance During Stepwise Stimulation From the Skin Surface to the Human Cortex

    NARCIS (Netherlands)

    Szelenyi, Andrea; Journee, Henricus Louis; Herrlich, Simon; Galistu, Gianni M.; van den Berg, Joris; van Dijk, J. Marc C.

    Background: Transcranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances. Objective: Threshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the

  5. Experimental Study of the Course of Threshold Current, Voltage and Electrode Impedance During Stepwise Stimulation From the Skin Surface to the Human Cortex

    NARCIS (Netherlands)

    Szelenyi, Andrea; Journee, Henricus Louis; Herrlich, Simon; Galistu, Gianni M.; van den Berg, Joris; van Dijk, J. Marc C.

    2013-01-01

    Background: Transcranial electric stimulation as used during intraoperative neurostimulation is dependent on electrode and skull impedances. Objective: Threshold currents, voltages and electrode impedances were evaluated with electrical stimulation at 8 successive layers between the skin and the cer

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

    Science.gov (United States)

    Lebib, A.; Hannanchi, R.; Beji, L.; EL Jani, B.

    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.

  7. 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.

  8. 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...... promise a good maintenance of the operating point of the floating-gate devices. Examples of utilizing of such bias sources in low-noise sensor preamplifiers are discussed....

  9. 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...... promise a good maintenance of the operating point of the floating-gate devices. Examples of utilizing of such bias sources in low-noise sensor preamplifiers are discussed....

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

    Science.gov (United States)

    2017-01-01

    to manually align the samples, so that the horizontal and vertical lattices are perfectly aligned with the stage left–right movement . Due to these...understand the axis movement portion of the code found in this technical report. When the user is facing the P200L, the following are true...on a diode or an Ids–Vds measurement on a high electron mobility transistor (HEMT). In lines 42 through 52, the script is simply checking to see

  11. Study of barrier inhomogeneities using I-V-T characteristics of Mo/4H-SiC Schottky diode

    Science.gov (United States)

    Ouennoughi, Z.; Toumi, S.; Weiss, R.

    2015-01-01

    In the present work we investigate the forward current-voltage (I-V) characteristics, over a wide temperature range 298-498 K, of Mo/4H-SiC Schottky diode for which aluminum ion implantation was used to create the high resistivity layer forming the guard ring. The (I-V) analysis based on Thermionic Emission (TE) theory shows a decrease of the barrier height ϕB and an increase of the ideality factor n when the temperature decreases. These anomalies are mainly due to the barrier height inhomogeneities at the metal/semiconductor interface as we get a Gaussian distribution of the barrier heights when we plot the apparent barrier height ϕap versus q/2kT. The mean barrier height and the standard deviation obtained values are ϕbarB0=1.160 eV and σ0=88.049 mV, respectively. However, by means of the modified Richardson plot Ln (Is /T2) - (q2 σ 0 2 / 2k2T2) versus q/kT, the mean barrier height and the Richardson constant values obtained are ϕbarB0=1.139 eV and A*=129.425 A/cm2 K2, respectively. The latter value of ϕbarB0 matches very well with the mean barrier height obtained from the plot of ϕap versus q/2kT. The Richardson constant is much closer to the theoretical value of 146 A/cm2 K2. The series resistance Rs is also estimated from the forward current-voltage characteristics of Mo/4H-SiC Schottky contact. This parameter shows strong temperature dependence. The T0 effect is validated for the 298-498 K temperature range for the used Schottky diode and provides a clear evidence for the barrier inhomogeneity at the Mo/4H-SiC interface. Finally, we note the impact of the implantation process as well as the choice of the used ion on the characterized parameters of the Schottky contact.

  12. 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.

  13. On the current-voltage relationship in auroral breakups and westwards-travelling surges

    Directory of Open Access Journals (Sweden)

    A. Olsson

    Full Text Available Auroral precipitating electrons pass through an acceleration region before entering the atmosphere. Regardless of what produces it, a parallel electric field is assumed to cause the acceleration. It is well known that from kinetic theory an expression for the corresponding upward field-aligned current can be calculated, which under certain assumptions can be linearized to j=KV. The K constant, referred to as the Lyons-Evans-Lundin constant, depends on the source density and thermal energy of the magnetospheric electrons; it is an important parameter in magnetosphere-ionosphere coupling models. However, the K parameter is still rather unknown, and values are found in a wide range of 10–8–10–10 S m–2. In this study, we investigated how the type of auroral structure affects the K values. We look at onset and westwards-travelling surge (WTS events and make comparisons with earlier results from observations of more stable auroral arcs. A new analysis technique for studying those magnetospheric parameters using ground-based measurements is introduced. Electron density measurements are taken with the EISCAT radar, and through an inversion technique the flux-energy spectra are calculated. Source densities, thermal energies and potential drops are estimated from fittings of accelerated Maxwellian distributions. With this radar technique we have the possibility to study the changes of the mentioned parameters during the development of onsets and the passage of surges over EISCAT. The study indicates that the linearization of the full Knight formulation holds even for the very high potential drops and thermal temperatures found in the dynamic onset and WTS events. The values of K are found to be very low, around 10–11 S m–2 in onset cases as well as WTS events. The results may establish a new technique where ionospheric

  14. Impact of charge transport on current-voltage characteristics and power-conversion efficiency of organic solar cells.

    Science.gov (United States)

    Würfel, Uli; Neher, Dieter; Spies, Annika; Albrecht, Steve

    2015-04-24

    This work elucidates the impact of charge transport on the photovoltaic properties of organic solar cells. Here we show that the analysis of current-voltage curves of organic solar cells under illumination with the Shockley equation results in values for ideality factor, photocurrent and parallel resistance, which lack physical meaning. Drift-diffusion simulations for a wide range of charge-carrier mobilities and illumination intensities reveal significant carrier accumulation caused by poor transport properties, which is not included in the Shockley equation. As a consequence, the separation of the quasi Fermi levels in the organic photoactive layer (internal voltage) differs substantially from the external voltage for almost all conditions. We present a new analytical model, which considers carrier transport explicitly. The model shows excellent agreement with full drift-diffusion simulations over a wide range of mobilities and illumination intensities, making it suitable for realistic efficiency predictions for organic solar cells.

  15. Double injection, resonant-tunneling recombination, and current-voltage characteristics in double-graphene-layer structures

    Energy Technology Data Exchange (ETDEWEB)

    Ryzhii, M. [Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Ryzhii, V. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005 (Russian Federation); Otsuji, T. [Research Institute for Electrical Communication, Tohoku University, Sendai 980-8577 (Japan); Maltsev, P. P. [Institute of Ultra High Frequency Semiconductor Electronics, Russian Academy of Sciences, Moscow 111005 (Russian Federation); Leiman, V. G. [Moscow Institute of Physics and Technology, Dolgoprudny, Moscow Region 141700 (Russian Federation); Ryabova, N. [Department of Computer Science and Engineering, University of Aizu, Aizu-Wakamatsu 965-8580 (Japan); Center for Photonics and Infrared Engineering, Bauman Moscow State Technical University, Moscow 105005 (Russian Federation); Mitin, V. [Department of Electrical Engineering, University at Buffalo, Buffalo, New York 1460-1920 (United States)

    2014-01-14

    We evaluate the effect of the recombination associated with interlayer transitions in ungated and gated double-graphene-layer (GL) structures on the injection of electrons and holes. Using the proposed model, we derive analytical expressions for the spatial distributions of the electron and hole Fermi energies and the energy gap between the Dirac points in GLs as well as their dependences on the bias and gate voltages. The current-voltage characteristics are calculated as well. The model is based on hydrodynamic equations for the electron and hole transports in GLs under the self-consistent electric field. It is shown that in undoped double-GL structures with weak scattering of electrons and holes on disorder, the Fermi energies and the energy gap are virtually constant across the main portions of GLs, although their values strongly depend on the voltages and recombination parameters. In contrast, the electron and hole scattering on disorder lead to substantial nonuniformities. The resonant inter-GL tunneling enables N-shaped current-voltage characteristics provided that GLs are sufficiently short. The width of the current maxima is much larger than the broadening of the tunneling resonance. In the double-GL structures with relatively long GLs, the N-shaped characteristics transform into the Z-shaped characteristics. The obtained results are in line with the experimental observations [Britnell et al., Nat. Commun. 4, 1794–1799 (2013)] and might be useful for design and optimization of different devices based on double-GL structures, including field-effect transistors and terahertz lasers.

  16. Development Of A Computerized I-V-Tracing System For Solar PV Module Testing

    Directory of Open Access Journals (Sweden)

    Gour Chand Mazumder

    2015-08-01

    Full Text Available this paper is about a development work of I-V-Curve tracing system. The system is automatic and replaces manual procedure of conventional I-V-Curve tracing method for Photovoltaic Solar Cell or Panel. This system is basically a combination of several blocks consisted by electronic devices and instrument groups. Some blocks are developed for measurement requirements and some are proprietary. This instrument can be used at solar module assembling industry for panel testing. In recent years there are significant rises on the counts of these types of business in developing countries. As this particular requires much lesser cost in comparison to other such type it is expected that this device may contribute to solar industry to help manufacturing process and quality control. Universities and laboratories may also find this suitable for their purpose. Although there are some little fluctuations in the acquired data the system can analyze the module characteristics properly.

  17. Adsorption behavior and current-voltage characteristics of CdSe nanocrystals on hydrogen-passivated silicon

    OpenAIRE

    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 to be highly nonhomogeneous, with an aggregation of most of the nanocrystals into islands of monolayer thickness. I-V spectra collected on nanocrystals adsorbed on n- and p-type substrates showed a...

  18. Electrodynamic stabilization conditions for high-temperature superconducting composites with different types of current-voltage characteristic nonlinearity

    Science.gov (United States)

    Arkharov, A. M.; Lavrov, N. A.; Romanovskii, V. R.

    2014-06-01

    The current instability is studied in high-temperature superconducting current-carrying elements with I- V characteristics described by power or exponential equations. Stability analysis of the macroscopic states is carried out in terms of a stationary zero-dimensional model. In linear temperature approximation criteria are derived that allow one to find the maximum allowable values of the induced current, induced electric field intensity, and overheating of the superconductor. A condition is formulated for the complete thermal stabilization of the superconducting composite with regard to the nonlinearity of its I- V characteristic. It is shown that both subcritical and supercritical stable states may arise. In the latter case, the current and electric field intensity are higher than the preset critical parameters of the superconductor. Conditions for these states depending on the properties of the matrix, superconductor's critical current, fill factor, and nonlinearity of the I- V characteristic are discussed. The obtained results considerably augment the class of allowable states for high-temperature superconductors: it is demonstrated that there exist stable resistive conditions from which superconductors cannot pass to the normal state even if the parameters of these conditions are supercritical.

  19. 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.

  20. Optimal I-V Curve Scan Time of Solar Cells and Modules in Light of Irradiance Level

    OpenAIRE

    Matic Herman; Marko Jankovec; Marko Topič

    2012-01-01

    High-efficiency solar cells and modules exhibit strong capacitive character resulting in limited speed of transient responses. A too fast I-V curve measurement can thus introduce a significant error due to its internal capacitances. This paper analyses the I-V curve error of a measured solar cell or module in light of scan time and irradiance level. It rests on a two-diode solar cell model extended by two bias-dependent capacitances, modelling the junction, and the diffusion capacitance. A me...

  1. I-V characteristics simulation of silicon carbide Ti/4H-SiC Schottky diode

    Science.gov (United States)

    Panchenko, P.; Rybalka, S.; Malakhanov, A.; Krayushkina, E.; Radkov, A.

    2016-12-01

    The simulation of current-voltage characteristics for 4H-SiC Schottky diode with Ti Schottky contact has been carried out with used of TCAD program. Obtained current-voltage characteristics has been analyzed and compared with theoretical and experimental results. It is established that the Schottky diode parameters (forward current, ideality coefficient, Schottky barrier height, breakdown voltage) obtained in proposed model are good agreement with data for such type diodes.

  2. Effect of inductive and capacitive coupling on the current-voltage characteristic and electromagnetic radiation from a system of Josephson junctions

    Science.gov (United States)

    Rahmonov, I. R.; Shukrinov, Yu. M.; Atanasova, P. Kh.; Zemlyanaya, E. V.; Bashashin, M. V.

    2017-01-01

    We have studied the current-voltage characteristic of a system of long Josephson junctions taking into account the inductive and capacitive coupling. The dependence of the average time derivative of the phase difference on the bias current and spatiotemporal dependences of the phase difference and magnetic field in each junction are considered. The possibility of branching of the current-voltage characteristic in the region of zero field step, which is associated with different numbers of fluxons in individual Josephson junctions, is demonstrated. The current-voltage characteristic of the system of Josephson junctions is compared with the case of a single junction, and it is shown that the observed branching is due to coupling between the junctions. The intensity of electromagnetic radiation associated with motion of fluxons is calculated, and the effect of coupling between junctions on the radiation power is analyzed.

  3. Ion sensitive probe measurement in the linear plasma device PSI-2

    Energy Technology Data Exchange (ETDEWEB)

    Ezumi, N. [Nagano National College of Technology, 716 Tokuma, Nagano 381-8550 (Japan)]. E-mail: ezumi@ec.nagano-nct.ac.jp; Kiss' ovski, Zh. [Faculty of Physics, Sofia University, Sofia 1164 (Bulgaria); Bohmeyer, W. [Max-Planck-Institut fuer Plasmaphysik, Bereich Plasmadiagnostik, Brook-Taylor-Str. 6, 12489 Berlin (Germany); Fussmann, G. [Max-Planck-Institut fuer Plasmaphysik, Bereich Plasmadiagnostik, Brook-Taylor-Str. 6, 12489 Berlin (Germany)

    2005-03-01

    The suitability of an ion sensitive probe (ISP) with respect to ion temperature (T {sub i}) measurements has been tested in the linear plasma generator in PSI-2. Current-voltage (I-V) characteristics were recorded as a function of two key parameters: shielding height (h) and potential differences between inner and outer electrodes (V {sub B}). It could be experimentally confirmed that the current within the electron saturation region is reduced with increasing h. Furthermore, the I-V characteristics change drastically when V {sub B} is varied. Radial profiles of the plasma parameters including plasma and floating potentials could be taken. Whereas the T {sub i} values determined by ISP in the plasma core region agree fairly with those obtained by using a local optical probe, severe interpretation difficulties occurred for the outer regions.

  4. Ionic polarization-induced current-voltage hysteresis in CH3NH3PbX3 perovskite solar cells.

    Science.gov (United States)

    Meloni, Simone; Moehl, Thomas; Tress, Wolfgang; Franckevičius, Marius; Saliba, Michael; Lee, Yong Hui; Gao, Peng; Nazeeruddin, Mohammad Khaja; Zakeeruddin, Shaik Mohammed; Rothlisberger, Ursula; Graetzel, Michael

    2016-02-01

    CH3NH3PbX3 (MAPbX3) perovskites have attracted considerable attention as absorber materials for solar light harvesting, reaching solar to power conversion efficiencies above 20%. In spite of the rapid evolution of the efficiencies, the understanding of basic properties of these semiconductors is still ongoing. One phenomenon with so far unclear origin is the so-called hysteresis in the current-voltage characteristics of these solar cells. Here we investigate the origin of this phenomenon with a combined experimental and computational approach. Experimentally the activation energy for the hysteretic process is determined and compared with the computational results. First-principles simulations show that the timescale for MA(+) rotation excludes a MA-related ferroelectric effect as possible origin for the observed hysteresis. On the other hand, the computationally determined activation energies for halide ion (vacancy) migration are in excellent agreement with the experimentally determined values, suggesting that the migration of this species causes the observed hysteretic behaviour of these solar cells.

  5. Device characterization and optimization of small molecule organic solar cells assisted by modelling simulation of the current-voltage characteristics.

    Science.gov (United States)

    Zuo, Yi; Wan, Xiangjian; Long, Guankui; Kan, Bin; Ni, Wang; Zhang, Hongtao; Chen, Yongsheng

    2015-07-15

    In order to understand the photovoltaic performance differences between the recently reported DR3TBTT-HD and DR3TBDT2T based solar cells, a modified two-diode model with Hecht equation was built to simulate the corresponding current-voltage characteristics. The simulation results reveal that the poor device performance of the DR3TBDTT-HD based device mainly originated from its insufficient charge transport ability, where an average current of 5.79 mA cm(-2) was lost through this pathway at the maximum power point for the DR3TBDTT-HD device, nearly three times as large as that of the DR3TBDT2T based device under the same device fabrication conditions. The morphology studies support these simulation results, in which both Raman and 2D-GIXD data reveal that DR3TBTT-HD based blend films exhibit lower crystallinity. Spin coating at low temperature was used to increase the crystallinity of DR3TBDTT-HD based blend films, and the average current loss through insufficient charge transport at maximum power point was suppressed to 2.08 mA cm(-2). As a result, the average experimental power conversion efficiency of DR3TBDTT-HD based solar cells increased by over 40%.

  6. S-shaped current-voltage characteristics of polymer composite films containing graphene and graphene oxide particles

    Science.gov (United States)

    Krylov, P. S.; Berestennikov, A. S.; Fefelov, S. A.; Komolov, A. S.; Aleshin, A. N.

    2016-12-01

    The resistive switching effects in composite films containing polyfunctional polymers, such as derivatives of carbazole (PVK), fluorene (PFD), and polyvinyl chloride (PVC), and also graphene particles (Gr) and graphene oxide (GO), the concentration of which in the polymer matrices varied in the range from 1 to 3 wt % corresponding to the percolation threshold in such systems, have been studied. The analysis of the elemental composition of the investigated composites by means of X-ray photoelectron spectroscopy have shown that the oxidation degree of Gr in GO is about 9 to 10%. It has been established that a sharp conductivity jump characterized by S-shaped current-voltage curves and the presence of their hysteresis occurs upon applying a voltage pulse to the Au/PVK (PFD; PVC): Gr (GO)/ITO/PET structures, where ITO is indium tin oxide, and PET is poly(ethylene terephthalate), with the switching time, t, in the range from 1 to 30 μs. The observed effects are attributed to the influence of redox reactions taking place on the Gr and GO particles enclosed in the polymer matrix, and the additional influence of thermomechanical properties of the polymer constituent of the matrix.

  7. Relationship of local i.v. complications and the method of intermittenti.v. access.

    Science.gov (United States)

    Hunter, E S; Bell, E; Staub, M A; Coyle, G

    1995-01-01

    Infiltration, infection, phlebitis, and thrombophlebitis are considered the most frequent complications of i.v. therapy. The purpose of our study was to determine if a difference existed in incidence of complications during i.v. infusions depending on whether the i.v. tubing is directly connected to the infusion device or the tubing is connected to the latex port of an i.v. lock using a needle. Background information, mehtod followed, and results obtained in the study are discussed.

  8. Nonlinear I-V characteristics of nanoparticle compacts and nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Herth, Simone [Rensselaer Polytechnic Institute, Troy, NY (United States); Bielefeld University, Bielefeld (Germany); Wang, Xiaoping; Hugener, Teresa; Schadler, Linda; Siegel, Richard [Rensselaer Polytechnic Institute, Troy, NY (United States); Hillborg, Henrik; Auletta, Tommaso [ABB AB, Corporate Research, Schweden (Sweden)

    2007-07-01

    Materials with nonlinear I-V characteristics are commonly used as field grading materials. In many cases, the non-linearity is achieved through the addition of equiaxed fillers to a polymer matrix. These composite field grading materials are optimized in terms of nonlinearity, conductivity, and breakdown strength. One limitation in designing new field grading materials is a robust understanding of the relationship between powder morphology, composition and electrical characteristics of the powder, as well as a robust understanding of the relationship between powder conductivity and non-linearity and composite non-linearity. In this work, treatment of ZnO powder with a SnF{sub 2} solution resulted in a powder that yielded highly non-linear behavior. The highest non-linearity was achieved for powders with at least two different phases and a rough surface, as indicated by transmission electron micrographs. In contrast, the non-linearity of the nanocomposite conductivity is mainly determined by the conductivity of the nanofiller. The electrical behavior of the non-linear powder can be understood by a polarization of the nanoparticles at the interfaces, whereas the nonlinearity of the nanocomposites can be explained by a tunnelling mechanism between two particles.

  9. Electrical characterization of gold-DNA-gold structures in presence of an external magnetic field by means of I-V curve analysis.

    Science.gov (United States)

    Khatir, Nadia Mahmoudi; Banihashemian, Seyedeh Maryam; Periasamy, Vengadesh; Ritikos, Richard; Abd Majid, Wan Haliza; Abdul Rahman, Saadah

    2012-01-01

    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.

  10. Parameters Affecting I-V Hysteresis of CH3NH3PbI3 Perovskite Solar Cells: Effects of Perovskite Crystal Size and Mesoporous TiO2 Layer.

    Science.gov (United States)

    Kim, Hui-Seon; Park, Nam-Gyu

    2014-09-04

    Current-voltage (I-V) characteristics of CH3NH3PbI3 perovskite solar cells are studied using a time-dependent current response with stepwise sweeping of the bias voltage. Compared with the crystalline Si solar cell showing time-independent current at a given bias voltage, the perovskite solar cells exhibit time-dependent current response. The current increases with time and becomes steady at forward scan from short-circuit to open-circuit, whereas it is decayed and saturated with time at reverse scan from open-circuit to short-circuit. Time-dependent current response eventually leads to I-V hysteresis depending on the scan direction and the scan rate. Crystal size of CH3NH3PbI3 and the mesoporous TiO2 (mp-TiO2) film are found to influence I-V hysteresis, where the I-V hysteresis is alleviated as crystal size increases and in the presence of mp-TiO2. The capacitance observed at low frequency (0.1 to 1 Hz), associated with dipole polarization, tends to diminish as size of perovskite and mp-TiO2 layer thickness increases, which suggests that the origin of hysteresis correlates to the capacitive characteristic of CH3NH3PbI3 and the degree of hysteresis depends strongly on perovskite crystal size and mesoporous TiO2 layer.

  11. Accurate extraction of WSe2 FETs parameters by using pulsed I-V method at various temperatures

    Science.gov (United States)

    Lee, Sung Tae; Cho, In Tak; Kang, Won Mook; Park, Byung Gook; Lee, Jong-Ho

    2016-11-01

    This work investigates the intrinsic characteristics of multilayer WSe2 field effect transistors (FETs) by analysing Pulsed I- V (PIV) and DC characteristics measured at various temperatures. In DC measurement, unwanted charge trapping due to the gate bias stress results in I- V curves different from the intrinsic characteristic. However, PIV reduces the effect of gate bias stress so that intrinsic characteristic of WSe2 FETs is obtained. The parameters such as hysteresis, field effect mobility (μeff), subthreshold slope ( SS), and threshold voltage ( V th) measured by PIV are significantly different from those obtained by DC measurement. In PIV results, the hysteresis is considerably reduced compared with DC measurement, because the charge trapping effect is significantly reduced. With increasing temperature, the field effect mobility (μeff) and subthreshold swing ( SS) are deteriorated, and threshold voltage ( V th) decreases.

  12. Inexpensive microcomputer-based system for solar cell I-V characterization

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Acevedo, A.; Herrera, E.; Valencia, H.

    1989-03-01

    A simple solar cell measurement system is described. The instrument is based on an inexpensive microcomputer with a single bidirectional 8-bit I/O port, in addition to 4 output bits taken from the joystick port. Currents up to 1.5 A and voltages up to 0.7 V can be measured with this system. The temperature of the cell is also measured. Solar cell parameters like open circuit voltage (V/sub oc/), short circuit current (I/sub sc/), series resistance (R/sub s/), shunt resistance (R/sub sh/), and filling factor (F.F.) are determined by a high-level language program that also displays the I-V curve on the monitor screen and stores the data on disk files.

  13. Current-voltage characteristics and charge DLTS spectra of proton-bombarded Schottky diodes on semi-insulating GaAs

    Energy Technology Data Exchange (ETDEWEB)

    Thurzo, I. (Inst. of Physics, Slovak Academy of Sciences, Bratislava (Slovakia)); Hrubcin, L. (Inst. of Electrical Engineering, Slovak Academy of Sciences, Bratislava (Slovakia)); Bartos, J. (Inst. of Physics, Slovak Academy of Sciences, Bratislava (Slovakia)); Pincik, E. (Inst. of Physics, Slovak Academy of Sciences, Bratislava (Slovakia))

    1993-10-01

    Changes in the current-voltage characteristics and charge DLTS spectra of Schottky diodes on semi-insulating GaAs after irradiation by protons at different energies and doses are presented and discussed. Apart from a progressive degradation of the Schottky barriers with enhanced proton energy and dose, there is a threshold, positioned between 10[sup 14] and 10[sup 15] protons/cm[sup 2], for observing trap-limited transients. (orig.)

  14. The current-voltage relationship revisited: exact and approximate formulas with almost general validity for hot magnetospheric electrons for bi-Maxwellian and kappa distributions

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    Full Text Available We derive the current-voltage relationship in the auroral region taking into account magnetospheric electrons for the bi-Maxwellian and kappa source plasma distribution functions. The current-voltage formulas have in principle been well known for a long time, but the kappa energy flux formulas have not appeared in the literature before. We give a unified treatment of the bi-Maxwellian and kappa distributions, correcting some errors in previous work. We give both exact results and two kinds of approximate formulas for the current density and the energy flux. The first approximation is almost generally valid and is practical to compute. The first approximation formulas are therefore suitable for use in simulations. In the second approximation we assume in addition that the thermal energy is small compared to the potential drop. This yields even simpler linear formulas which are suitable for many types of event studies and which have a more transparent physical interpretation than the first approximation formulas. We also show how it is possible to derive the first approximation formulas even for those distributions for which the exact results can not be computed analytically. The kappa field-aligned conductance value turns out always to be smaller than the corresponding Maxwellian conductance. We also verify that the obtained kappa current density and energy flux formulas go to Maxwellian results when κ→∞.

    Key words. Current-voltage relationship · Bi-Maxwellian distributions · Kappa distribution

  15. 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.

  16. Model I - V curves and figures of merit of underdamped deterministic Josephson ratchets

    Science.gov (United States)

    Goldobin, E.; Menditto, R.; Koelle, D.; Kleiner, R.

    2016-09-01

    We propose simple models for the current-voltage characteristics of typical Josephson ratchets. We consider the case of a ratchet working against a constant applied counter force and derive analytical expressions for the key characteristics of such a ratchet: rectification curve, stopping force, input and output powers, and rectification efficiency. Optimization of the ratchet performance is discussed.

  17. Effect of filament supports on emissive probe measurements

    Energy Technology Data Exchange (ETDEWEB)

    Wang, X.; Howes, C. T. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80309 (United States); NASA Lunar Science Institute: Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80309 (United States); Horanyi, M. [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colorado 80309 (United States); NASA Lunar Science Institute: Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80309 (United States); Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States); Robertson, S. [NASA Lunar Science Institute: Colorado Center for Lunar Dust and Atmospheric Studies, Boulder, Colorado 80309 (United States); Department of Physics, University of Colorado, Boulder, Colorado 80309 (United States)

    2013-01-15

    We have constructed an emissive probe with a thin tungsten filament spot-welded across two nickel wires insulated with ceramic paint. We show that the ceramic supports covering the nickel wires have a large effect on the potential measurements in low-density plasmas. It is found that the potential measured by the emissive probe is more negative than the potential derived from a Langmuir probe current-voltage (I-V) characteristic curve when the plasma density is so low that the emitting filament remains immersed in the sheaths of the ceramic supports. The length of the filament L needs to be larger than about 2 Debye lengths (L > 2{lambda}{sub De}) in order to avoid the influence of the ceramic supports and to achieve reliable plasma potential measurements using emissive probes.

  18. 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

  19. 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

  20. 钙钛矿太阳能电池中S形伏安特性研究∗%S-shap ed current-voltage characteristics in p erovskite solar cell

    Institute of Scientific and Technical Information of China (English)

    石将建; 孟庆波; 卫会云; 朱立峰; 许信; 徐余颛; 吕松涛; 吴会觉; 罗艳红; 李冬梅

    2015-01-01

    Analysis of the DC current-voltage (I-V ) characteristics is an effective approach to investigate the charge transport properties in a solar cell. The perovskite solar cell attracted wide research interest in the past two years due to their outstanding photovoltaic capacity. However, the charge transport characteristics and working principles of this kind of cells have not been clearly clarified. In this work, the I-V characteristics of the perovskite solar cell have been investigated from the experimental and theoretical perspective views. Moreover, the S-shaped I-V feature coming from the limitation of interfacial charge transport was focused on. With a series connected diode model, the I-V characteristics of the solar cell are investigated and simulated. It is found that the charge accumulation appears gradually when the interfacial charge transport velocity is decreased, lowering the output of the cell. When the interfacial charge transport decreases gradually, the short-circuit current density and the fill factor of the cell also decrease obviously. In experiments, limitations of charge transport at the front and back contacts of the cell have been designed, successfully producing varied S-shaped I-V features. It is found that both in the hole transport material-free and in the p-i-n perovskite solar cells, the S-shaped I-V characteristics can appear. Moreover, the origins of these features in various experimental conditions have also been discussed, which can be the energy barriers or large charge transport resistances in the cell. These energy barriers and resistances will lower the charge transport velocity and may cause charge accumulation, thus leading to the appearence of the S-shaped features. Meanhiwle, the emerging S-shaped I-V curves all have their own features, which may be due to the specific interfacial energy band structures. Thus, to promote the cell performance, the charge transport and interface energy barrier should be attached importance to

  1. Use of i.v. insulin in well-controlled non-insulin-dependent diabetics undergoing major surgery.

    Science.gov (United States)

    Raucoules-Aimé, M; Labib, Y; Levraut, J; Gastaud, P; Dolisi, C; Grimaud, D

    1996-02-01

    We conducted a randomized, prospective study to assess the effect of i.v. insulin on blood glucose control, development of ketone bodies and hormonal changes in 60 well-controlled, non-insulin-dependent diabetics (NIDDM) undergoing major surgery. In group A, patients were given only 0.9% saline; in group B, patients were given insulin as a continuous i.v. infusion (1.25 u. h-1); in group C, patients were given insulin 10 u. i.v. boluses every 2 h. Patients in all three groups were given insulin 5 u. when their intraoperative blood glucose concentration increased to greater than 11.1 mmol litre-1. Blood glucose concentrations were measured every 15 min, from just before induction of anaesthesia to 2 h after surgery. Plasma lactate, pyruvate, ketone body, C-peptide and counter-regulatory hormone concentrations were also measured. Blood glucose concentrations in the three groups did not differ significantly. There was a mild-to-moderate increase in plasma ketone body concentrations in group A, but without any deleterious consequences. Plasma C-peptide concentrations decreased significantly in groups B and C, especially in patients given bolus injections of insulin. Plasma growth hormone concentrations also increased significantly in group B and C patients. This study indicated that the "no insulin--no glucose" regimen was a simple, effective way to control blood glucose in well-controlled NIDDM patients, provided blood glucose was measured frequently and insulin used appropriately.

  2. Measuring Schottky barrier height at graphene/SiC junction

    Science.gov (United States)

    Tomer, D.; Hudy, L.; Rajput, S.; Li, L.

    2014-03-01

    When graphene is interfaced with a semiconductor, a Schottky junction forms with rectifying properties. In this work, we measured the Schottky barrier heights of graphene/SiC Schottky diodes using current-voltage (I-V) measurement. Chemical vapor deposited graphene was transferred onto semiconductor surfaces of opposite polarization: the hydrogen-terminated Si- and C-faces of α-SiC, which was confirmed by Raman spectroscopy and scanning tunneling microscopy. The Schottky barrier height is found to be sensitive to the polarization of the substrate and surface preparation. On the Si-face, a barrier of 0.47 eV is found. These results will be compared with earlier work as well as our in situ scanning tunneling spectroscopy results. Supported by DOE (DE-FG02-07ER46228).

  3. Double exponential I-V characteristics and double Gaussian distribution of barrier heights in (Au/Ti)/Al2O3/ n-GaAs (MIS)-type Schottky barrier diodes in wide temperature range

    Science.gov (United States)

    Güçlü, Çiğdem Ş.; Özdemir, Ahmet Faruk; Altindal, Şemsettin

    2016-12-01

    In this study, current conduction mechanisms of the sample (Au/Ti)/Al2O3/ n-GaAs were investigated in detail using current-voltage (I-V) measurements in the temperature range of 80-380 K. The semilogarithmic I-V plots reveal two distinct linear regions with different slopes between 0.07-0.30 and 0.30-0.69 V which are called as Region I (RI) and Region II (RII), respectively. The ideality factor ( n) and zero-bias barrier height (Φ_{{bo}}) were found to be strong functions of temperature and voltage. In both regions, as the temperature increases, Φ_{{bo}} increases, whereas the value of n decreases. The high value of n at low temperatures is an evidence of deviation from thermionic emission, and it cannot be explained solely by tunneling mechanism, the existence of surface states and interfacial layer. Therefore, the Φ_{{bo}} versus q/kT plots were drawn for two linear regions of lnI-V plots, and these plots also revealed two distinct linear regions with different slopes between two temperature regions of 80-170 and 200-380 K which are called as low- and high-temperature range (LTR and HTR), respectively. Such behavior of these plots confirmed the existence of double Gaussian distribution (DGD) in the samples which in turn has mean barrier heights bar{Φ}_{{bo}} and standard deviations ( σ s). These values were obtained from the intercept and slope of these plots as 0.38 eV and 0.061 V for LTR and as 0.88 eV and 0.142 V for HTR (in RI), whereas they were obtained as 0.37 eV and 0.061 V for LTR and as 0.92 eV and 0.148 V for HTR (in RII), respectively. Thus, the modified ln( I s/ T 2)- q 2 σ s 2 /2 k 2 T 2 versus q/ kT plots were drawn, and the values of (bar{Φ}_{{bo}}) and effective Richardson constant ( A *) were extracted from the intercept and slope of these plots as 0.39 eV and 7.07 A/cm2 K2 for LTR and as 0.92 eV and 8.158 A/cm2 K2 for HTR (in RI), whereas they were extracted as 0.38 eV and 7.92 A/cm2 K2 for LTR and as 0.94 eV and 4.66 A/cm2 K2 for HTR

  4. Current-voltage characteristics with several threshold currents in insulating low-doped La1-xSrxMnO3 (x=0.10) thin films

    Institute of Scientific and Technical Information of China (English)

    ZHAO Kun; FENG Jiafeng; HE Meng; L(U) Huibin; JIN Kuijuan; ZHOU Yueliang; YANG Guozhen3

    2008-01-01

    The current-induced resistive switching behavior in the micron-scale pillars of low-doped La0.9Sr0.1MnO3 thin films using laser molecular-beam epitaxy was reported. It was demonstrated that the current-voltage curves at 120 K showed hysteresis with several threshold currents corresponding to the switching in resistance to metastable low resistance states, and finally, four closed loops were formed. A mode was proposed, which was based on the low-temperature canted antiferromagnetism ordering for a lightly doped insulating regime.

  5. 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......:PCBM-PEDOT:PSS-Ag. The devices were manufactured using a combination of slot-die coating and screen printing; they were then encapsulated by lamination using a polymer based barrier material. All manufacturing steps were carried out in ambient air. The freshly prepared devices showed a consistent inflection point in the IV...

  6. Study of Electrical Conduction Mechanism of Organic Double-Layer Diode Using Electric Field Induced Optical Second Harmonic Generation Measurement.

    Science.gov (United States)

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

    2016-04-01

    By using electric field induced optical second harmonic generation (EFISHG) and current voltage (I-V) measurements, we studied the electrical transport mechanism of organic double-layer diodes with a structure of Au/N, N'-di-[(1-naphthyl)-N, N'-diphenyl]-(1,1'-biphenyl)-4,4'-diamine (a-NPD)/poly(methyl methacrylate) (PMMA)/indium zinc oxide (IZO). Here the α-NPD is a carrier transport layer and the PMMA is an electrical insulating layer. The current level was very low, but the I-V characteristics showed a rectifying behavior. The EFISHG measurement selectively and directly probed the electric field across the α-NPD layer, and showed that the electric field across the a-NPD layer is completely relaxed owing to the charge accumulation at the a-NPD/PMMA interface in the region V > 0, whereas the carrier accumulation was not significant in the region V < 0. On the basis of these experimental results, we proposed a model of the rectification. Further, by coupling the I-V characteristics with the EFISHG measurement, the I-V characteristics of the diodes were well converted into the current-electric field (I-E) characteristics of the α-NPD layer and the PMMA layer. The I-E characteristics suggested the Schottky-type conduction governs the carrier transport. We conclude that the I-V measurement coupled with the EFISHG measurement is very useful to study carrier transport mechanism of the organic double-layer diodes.

  7. Elucidation of barrier homogeneity in ZnO/P3HT:PCBM junctions through temperature dependent I-V characteristics

    Science.gov (United States)

    Khare, Neeraj; Zubair Ansari, Mohd; Hoye, Robert L. Z.; Iza, Diana C.; MacManus-Driscoll, Judith L.

    2016-07-01

    The current-voltage (I-V) characteristics of ZnO/P3HT:PCBM junctions using as-deposited ZnO and 300 °C-annealed ZnO (prior to device fabrication) were probed as a function of temperature. The ZnO films were synthesized using two scalable, low temperature methods: Atmospheric pressure spatial atomic layer deposition (AP-SALD) and electrodeposition (ED). In both cases the zero bias Schottky barrier height ({Φ\\text{B}} ) decreases and ideality factor (n) increases with a reduction in the operating temperature of the junctions. This was attributed to the presence of barrier inhomogeneities at the interface from surface states/defects in the ZnO causing a localized variation of work function. For the as-deposited ZnO junctions, two mean barrier heights, arising from a large density of surface states was observed. For the annealed ZnO junction one mean barrier height was observed, indicating reduction in the inhomogeneities of barrier height at the interface for the annealed ZnO. The photoresponce of ZnO/P3HT:PCBM junction was higher for the annealed ZnO which is due to the higher mean barrier height and lower value of ideality factor. This demonstrates that moderate annealing of chemically grown ZnO is crucial for reducing surface defects and barrier inhomogeneities.

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

    CERN Document Server

    Matorras Cuevas, Pablo

    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.

  9. ATTENUATION OF HEMODYNAMIC RESPONSE TO EXTUBATION WITH I.V. LIGNOCAINE: A RANDOMIZ ED CLINICAL TRIAL

    Directory of Open Access Journals (Sweden)

    Savitha

    2014-01-01

    Full Text Available BACKGROUND AND OBJECTIVES : Hemodynamic and cough response to extubation can result in raised heart rate , blood pressures and intracavitary pressures which could be detrimental in high - risk patients. The aim of our study was to estimate the difference in hemodynamic a nd cough response to oro trache a l tube extubation with saline (control group , I.V lignocaine 0.5mg/kg and I.V lignocaine 1mg/kg and to evaluate the comparative efficacy between the groups. METHODS : In our clinical prospective descriptive double blind stud y 90 patients of either sex scheduled for elective surgical procedures requiring orotracheal intubation , who met inclusion criteria, we re considered. They were randomly divided into three groups of 30 each , Group - 1 (control - saline , group - 2 (lignocaine 0.5 mg/kg and group - 3 (lignocaine 1mg/kg. They were administered study drug 2 minutes prior to extubation , following a standard peri operative anesthetic course. Hemodynamic parameters like heart rate , systolic blood pressure , diastolic blood pressure and me an arterial pressure (HR , SBP , DBP and MAP prior to administration of the study drug and at 1min , 3min , 5min and 10min post extubation were considered for statistical analysis. Post extubation cough graded as per Eshak’s grading (Grade 0 , 1 , 2 and 3. Dat a obtained were analyzed using Analysis of variance (ANOVA , Post - hoc Tukey test and Chi - square/Fisher Exact test. Results on continuous measurement were , presented on Mean ± SD. Significance was assessed at 5% level of significance. RESULTS : In control group , there was significant rise in HR , SBP and MAP throughout the study period and the incidence of moderate and severs cough was 43.3% and 30% respectively. Diastolic blood pressure and mean arterial pressures attenuation with lignocaine 1mg/kg found to be superior (P<0.001. There was no significant difference in heart rate and systolic blood pressure attenuation between patients who

  10. Langmuir probe Diagnostic for local parameter measurement in Magnetized Plasma using LabVIEW

    Directory of Open Access Journals (Sweden)

    Bijal Vara

    2014-03-01

    Full Text Available In recent years, plasma technology is used by Semiconductor, thin film industries for deposit layers, etching process and surface modification. So it is necessary to understanding internal plasma parameter. Langmuir probe is one of the simplest techniques which is used to measure wide range of plasma parameter like plasma potential, floating potential, electron temperature, electron energy distribution function (EEDF etc. Langmuir current voltage characteristic is obtained by varying bias voltage of the probe. LabVIEW is most powerful Microsoft window compatible software which is used to immediate data acquisition and analysis. In this paper describes analysis of Langmuir data using LabVIEW software which automatically measure I-V Plasma probe Characteristics and obtain EEDF of plasma.

  11. Optical and electrical measurement of energy transfer between nanocrystalline quantum dots and photosystem I.

    Science.gov (United States)

    Jung, Hyeson; Gulis, Galina; Gupta, Subhadra; Redding, Kevin; Gosztola, David J; Wiederrecht, Gary P; Stroscio, Michael A; Dutta, Mitra

    2010-11-18

    In the natural photosynthesis process, light harvesting complexes (LHCs) absorb light and pass excitation energy to photosystem I (PSI) and photosystem II (PSII). In this study, we have used nanocrystalline quantum dots (NQDs) as an artificial LHC by integrating them with PSI to extend their spectral range. We have performed photoluminescence (PL) and ultrafast time-resolved absorption measurements to investigate this process. Our PL experiments showed that emission from the NQDs is quenched, and the fluorescence from PSI is enhanced. Transient absorption and bleaching results can be explained by fluorescence resonance energy transfer (FRET) from the NQDs to the PSI. This nonradiative energy transfer occurs in ∼6 ps. Current-voltage (I-V) measurements on the composite NQD-PSI samples demonstrate a clear photoresponse.

  12. Optical and Electrical Measurement of Energy Transfer between Nanocrystalline Quantum Dots and Photosystem I

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Hyeson [Univ. of Illinois, Chicago, IL (United States); Gulis, G. [Univ. of Alabama, Tuscaloosa, AL (United States); Gupta, S. [Univ. of Alabama, Tuscaloosa, AL (United States); Redding, K. [Arizona State Univ., Mesa, AZ (United States); Gosztola, D. J. [Argonne National Lab. (ANL), Argonne, IL (United States); Wiederrecht, Gary P [Argonne National Lab. (ANL), Argonne, IL (United States); Stroscio, M. A. [Univ. of Illinois, Chicago, IL (United States); Dutta, M. [Univ. of Illinois, Chicago, IL (United States)

    2010-08-31

    In the natural photosynthesis process, light harvesting complexes (LHCs) absorb light and pass excitation energy to photosystem I (PSI) and photosystem II (PSII). In this study, we have used nanocrystalline quantum dots (NQDs) as an artificial LHC by integrating them with PSI to extend their spectral range. We have performed photoluminescence (PL) and ultrafast time-resolved absorption measurements to investigate this process. Our PL experiments showed that emission from the NQDs is quenched, and the fluorescence from PSI is enhanced. Transient absorption and bleaching results can be explained by fluorescence resonance energy transfer (FRET) from the NQDs to the PSI. This nonradiative energy transfer occurs in ~6 ps. Current-voltage (I-V) measurements on the composite NQD-PSI samples demonstrate a clear photoresponse.

  13. High concentration effects of neutral-potential-well interface traps on recombination dc current-voltage lineshape in metal-oxide-silicon transistors

    Science.gov (United States)

    Chen, Zuhui; Jie, Bin B.; Sah, Chih-Tang

    2008-11-01

    Steady-state Shockley-Read-Hall kinetics is employed to explore the high concentration effect of neutral-potential-well interface traps on the electron-hole recombination direct-current current-voltage (R-DCIV) properties in metal-oxide-silicon field-effect transistors. Extensive calculations include device parameter variations in neutral-trapping-potential-well electron interface-trap density NET (charge states 0 and -1), dopant impurity concentration PIM, oxide thickness Xox, forward source/drain junction bias VPN, and transistor temperature T. It shows significant distortion of the R-DCIV lineshape by the high concentrations of the interface traps. The result suggests that the lineshape distortion observed in past experiments, previously attributed to spatial variation in surface impurity concentration and energy distribution of interface traps in the silicon energy gap, can also arise from interface-trap concentration along surface channel region.

  14. The role of cathodic current in PEO of aluminum: Influence of cationic electrolyte composition on the transient current-voltage curves and the discharges optical emission spectra

    Science.gov (United States)

    Rogov, A. B.; Shayapov, V. R.

    2017-02-01

    In this paper, the influence of cationic electrolytes composition on electrical and optical responses of plasma electrolytic oxidation process of A1050 aluminum alloy under alternating polarization is considered. The electrolytes consist of 0.1 M boric acid with addition of one of the following hydroxides: LiOH, NaOH, KOH, tetraethylammonium hydroxide, Ca(OH)2 up to pH value 9.2. Coatings microstructure, elemental and phase compositions were studied by SEM, EDS and XRD. It was shown that the hysteresis of anodic current-voltage curve (specific feature of "Soft sparking" PEO) was clear observed in the presence of sodium and potassium cations. It was found that composition of microdischarges plasma is also affected by the nature of the cations. It was shown that there are a number of reciprocal processes, which take place under anodic and cathodic polarization.

  15. 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...... that the findings are applicable to various other device structures based on semiconducting oxides. The findings may have influences on the possibilities and scale-up of polymer solar technologies.......:PCBM-PEDOT:PSS-Ag. The devices were manufactured using a combination of slot-die coating and screen printing; they were then encapsulated by lamination using a polymer based barrier material. All manufacturing steps were carried out in ambient air. The freshly prepared devices showed a consistent inflection point in the IV...

  16. On the interpretation of current-voltage curves in ionization chambers using the exact solution of the Thomson problem

    Science.gov (United States)

    Ridenti, M. A.; Pascholati, P. R.; Gonçalves, J. A. C.; Bueno, C. C.

    2015-09-01

    The I - ΔV characteristic curve of a well type ionization chamber irradiated with 192Ir sources (0.75 Ci-120 Ci) was fitted using the exact solution of the Thomson problem. The recombination coefficient and saturation current were estimated using this new approach. The saturation current was compared with the results of the conventional method based on Boag-Wilson formula. It was verified that differences larger than 1% between both methods only occurred at activities higher than 55 Ci. We concluded that this new approach is recommended for a more accurate estimate of the saturation current when it is not possible to measure currents satisfying the condition I /Isat > 0.95. From the calibration curve the average value of pairs of carriers created per unit volume was estimated to be equal to η = 8.1 ×10-3cm-3s-1 Bq-1 and from that value it was estimated that ~ 17 pairs were created on average per second for each decay of the source.

  17. 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...... analysis is based on a single scaling factor, extracted from the experimental I(V) characteristics. For both polarities, this scaling factor transforms the change of bias voltage into a change of electron energy. The latter is determined with respect to the top of the potential barrier of the contact....... 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...

  18. 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.

  19. Effect of the mobility on (I-V) characteristics of the MOSFET

    Energy Technology Data Exchange (ETDEWEB)

    Benzaoui, Ouassila, E-mail: o-benzaoui@yahoo.fr [Technology Department, Faculty of Technology, 20 August 1955 University, BP 26, El-Hadaiek Street 21000 Skikda, Algeria and Department of Physics, Faculty of Science, Thin Films and Interfaces Laboratory, P. B 325, Ain El Bey Street, Mentouri Univers (Algeria); Azizi, Cherifa, E-mail: aziziche@yahoo.fr [Department of Material Sciences, Larbi Ben M' hidi University, BP 358, Constantine Street, 04000 Oum El-Bouaghi, Algeria and Department of Physics, Faculty of Science, Thin Films and Interfaces Laboratory, P. B 325, Ain El Bey Street, Mentouri Univers (Algeria)

    2013-12-16

    MOSFET Transistor was the subject of many studies and research works (electronics, data-processing, telecommunications...) in order to exploit its interesting and promising characteristics. The aim of this contribution is devoted to the effect of the mobility on the static characteristics I-V of the MOSFET. The study enables us to calculate the drain current as function of bias in both linear and saturated modes; this effect is evaluated using a numerical simulation program. The influence of mobility was studied. Obtained results allow us to determine the mobility law in the MOSFET which gives optimal (I-V) characteristics of the component.

  20. 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 on the orien......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...

  1. 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...... and its control software offers the flexibility to automatically adapt to the different irradiation conditions set by the flashing solar simulator. Simulation and experimental tests have been carried out, in order to verify the behaviour and performance of the designed I-V curve tracer....

  2. Get A.C.T.I.V.E: Engaging Middle School Readers with Text.

    Science.gov (United States)

    Goodman, Amy

    2003-01-01

    Explains that a Middle School Literacy Teacher Expert supports and guides teachers with innovative strategies to help students master basic literacy skills to become lifelong learners. Explains the A.C.T.I.V.E. strategy to encourage students to ask, comment, track down, infer, visualize, and Eureka! (synthesize). (PM)

  3. 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.

  4. Multiple steady state current-voltage characteristics in drift-diffusion modelisation of N type and semi-insulating GaAs Gunn structures

    Science.gov (United States)

    Manifacier, J. C.

    2010-12-01

    Theoretical and numerical investigations of carriers transport in N-Semi-Insulating (SI)-N and P-SI-P diodes is extended to the case of extrinsic (N type) or SI samples with Gunn like electric field dependent mobilities. The results obtained in a preceding publication [1] are valid as long as the bulk electric field does not increase above a threshold field E th associated with the beginning of negative electron differential mobility values: μ n,diff = ( dv n/ dE) diodes. SI(N -) characterizes a SI layer which keeps, under applied bias, a free electron concentration close to its thermal equilibrium value up to the beginning of electron space charge injection. A systematic study has been made by varying the contact boundary properties: flat band, metallic, N + or P +; the length of the sample and the electric parameters of the deep compensating trap of the SI layers. We show that these steady state numerical instabilities are related to the existence of multiple current-voltage solutions when numerical modelisation is made using the drift-diffusion model.

  5. Irreversibility in room temperature current-voltage characteristics of NiFe2O4 nanoparticles: A signature of electrical memory effect

    Science.gov (United States)

    Dey, P.; Debnath, Rajesh; Singh, Swati; Mandal, S. K.; Roy, J. N.

    2017-01-01

    Room temperature I-V characteristics study, both in presence and absence of magnetic field (1800 Oe), has been performed on NiFe2O4 nanoparticles, having different particle size (V~14, 21 and 31 nm). Our experiments on these nanoparticles provide evidences for: (1) electrical irreversibility or hysteretic behaviour; (2) positive magnetoresistance and (3) magnetic field dependent electrical irreversibility or hysteresis in the sample. "Hysteretic" nature of I-V curve reveals the existence of electrical memory effect in the sample. Significantly, such hysteresis has been found to be tuned by magnetic field. In order to explain the observed electrical irreversibility, we have proposed a phenomenological model on the light of induced polarization in the sample. Both the positive magnetoresistance and the observed magnetic field dependence of electrical irreversibility have been explained through magnetostriction phenomenon. Interestingly, such effects are found to get reduced with increasing particle size. For NiFe2O4 nanoparticles having V=31 nm, we did not observe any irreversibility effect. This feature has been attributed to the enhanced grain surface effect that in turn gives rise to the residual polarization and hence electrical memory effect in NiFe2O4 nanoparticles, having small nanoscopic particle size.

  6. Effects of hydrogen, oxygen, and argon annealing on the electrical properties of ZnO and ZnO devices studied by current-voltage, deep level transient spectroscopy, and Laplace DLTS

    Science.gov (United States)

    Mtangi, W.; Auret, F. D.; Meyer, W. E.; Legodi, M. J.; Janse van Rensburg, P. J.; Coelho, S. M. M.; Diale, M.; Nel, J. M.

    2012-05-01

    Effects of annealing ZnO in hydrogen, oxygen, and argon have been investigated using deep level transient spectroscopy (DLTS) and Laplace-DLTS (LDLTS) measurements. Current-voltage (IV) measurements indicate a decrease in zero-bias barrier height for all the annealed samples. Conventional DLTS measurements reveal the presence of three prominent peaks in the un-annealed and annealed samples. A new peak with an activation enthalpy of 0.60 eV has been observed in the H2 annealed samples, while an estimated energy level of 0.67 eV has been observed in Ar annealed samples. O2 annealing does not introduce new peaks but causes a decrease in the concentration of the E3 peak and an increase in concentration of the E1 peak. The concentrations of all the intrinsic defects have decreased after H2 and Ar annealing; with Ar annealing giving peaks with the lowest concentrations. The E2 peak anneals out after annealing ZnO in Ar and H2 at 300 °C. From the annealing behaviour of E3, we have attributed to transition metal ion related defects, while E4 has been explained as a defect, whose formation favours oxygen deficient conditions. Laplace DLTS has successfully been employed to resolve the closely spaced energy levels in the E4 peak, splitting it into three peaks with energy levels, 0.68 eV, 0.58 eV, and 0.50 eV below the minimum of the conduction band for the Ar annealed sample.

  7. New method of parameters extraction from dark I-V curve

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, A.; Marchand, J.J.; Fave, A.; Laugier, A. [INSA de Lyon, Villeurbanne (France). Lab. de Physique de la Matiere

    1997-12-31

    It is very necessary, for solar cells, to obtain a low series resistance and to be able to determine it with accuracy because it is an important parameter of fill factor and efficiency improvement. In the case of low series resistance, the authors have developed a new method of parameters extraction from only one dark I-V characteristic. They have also improved another technique (the integral) of series resistance extraction. They have compared these two methods to two other ones (the derivative and Lee et al. method). The method gives very good results. Moreover, it is very simple to use and presents the advantage of being independent of the voltage step in contrary to the derivative and to the integral. They have then applied their technique to a whole solar cell I-V curve and the results are very good.

  8. Rapid Drinking Devices Constructed from I.V. Bags and Plastic Squeeze Bottles,

    Science.gov (United States)

    1985-04-01

    i D-153 652 RAPID DRINKING DEVICES CONSTRUCTED FROM IY BAS AND 1/1 I PLASTIC SQUEEZE BOTTLES (U) A MY RESEARCH INST OF I ENVIRONMENTAL MEDICINE...TITLE (and Subtitle) S. TYPE OF REPORT & PERIOD COVEREDLf Rapid Drinking Devices Constructed Fram I.V. ( Bags and Plastic Squeeze Bottles 6...running. The primary problem with using a plastic water bottle during a race is that it ~ must be held upright and squeezed tightly while the runner

  9. PRE - MEDICATION WITH I.V. LIDOCAINE VS I.V. CLONIDINE IN ATTENUATING THE PRESSO R RESPONSE DURING LARYNGOSCOPY AND ENDOTRACHEAL INTUBATION

    Directory of Open Access Journals (Sweden)

    Irfan

    2015-08-01

    Full Text Available AIM OF STUDY: This randomized prospective study is done to compare the effects o f single premedication dose of I.V lignocaine with IV clonidine in attenuating pressor response to laryngoscopy & endotracheal intubation. METHOD: Patients were randomly divided into 2 groups of 50 each. Group I patients received lignocaine 1.5mg/kg and Group II patients received Clonidine 3mcg/kg 15 min before laryngoscopy. HR (Heart Rate , SBP (Systolic blood pressure , DBP (Diastolic BP , MAP (Mean Arterial Pressure were monitored at 1 , 3 , 5 , 7 and 10 minute intervals from the onset of laryngoscopy. Respectively. Patients were maintained with O2 , N2O , Isoflurane and vecuronium at titrated doses. Results the rise in heart rate , systolic blo od pressure , diastolic blood pressure and mean arterial pressure in group I is significantly high compared to group II . I NTERPRETATION AND CONCLUSION: Clonidine in a dose of 3 microgms/kg was more effective than lidocaine 1.5 mg/kg for attenuating haemodyn amic responses to laryngoscopy and intubation. KEYWORDS : Clonidine; Lidocaine; Laryngoscopy & endotracheal intubation; Attenuation of haemodynamic response; Heart rate; Systolic blood pressure; Diastolic blood pressure; Mean arterial pressure .

  10. LEED I-V and DFT structure determination of the (√3 × √3)R30° Pb-Ag(111) surface alloy.

    Science.gov (United States)

    McLeod, I M; Dhanak, V R; Lahti, M; Matilainen, A; Pussi, K; Zhang, K H L

    2011-07-06

    The deposition of 1/3 of a monolayer of Pb on Ag(111) leads to the formation of PbAg(2) surface alloy with a long range ordered (√3 × √3)R30° superstructure. A detailed analysis of this structure using low-energy electron diffraction (LEED) I-V measurements together with density functional theory (DFT) calculations is presented. We find strong correlation between experimental and calculated LEED I-V data, with the fit between the two data sets having a Pendry's reliability factor of 0.21. The Pb atom is found to replace one top layer Ag atom in each unit cell, forming a substitutional PbAg(2) surface alloy, as expected, with the Pb atoms residing approximately 0.4 Å above the Ag atoms due to their size difference. DFT calculations are in good agreement with the LEED results.

  11. 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.

  12. Bianchi Type-I, V and VIo models in modified generalized scalar–tensor theory

    Indian Academy of Sciences (India)

    T Singh; R Chaubey

    2007-08-01

    In modified generalized scalar–tensor (GST) theory, the cosmological term is a function of the scalar field and its derivatives $\\dot{}^{2}$. We obtain exact solutions of the field equations in Bianchi Type-I, V and VIo space–times. The evolution of the scale factor, the scalar field and the cosmological term has been discussed. The Bianchi Type-I model has been discussed in detail. Further, Bianchi Type-V and VIo models can be studied on the lines similar to Bianchi Type-I model.

  13. Inverse I-V Injection Characteristics of ZnO Nanoparticle-Based Diodes.

    Science.gov (United States)

    Mundt, Paul; Vogel, Stefan; Bonrad, Klaus; von Seggern, Heinz

    2016-08-10

    Simple Al/ZnO(NP)/Au diodes produced by spin coating of ZnO nanoparticle dispersions (ZnO(NP)) on Al/Al2O3 and Au substrates and subsequent Au deposition have been investigated to understand electron injection properties of more complex devices, incorporating ZnO(NP) as injection layer. Inverse I-V characteristics have been observed compared to conventional Al/ZnO(SP)/Au diodes produced by reactive ion sputtering of ZnO. SEM micrographs reveal that the void-containing contact of ZnO(NP) with the bottom Al electrode and the rough morphology of the top Au electrode are likely to be responsible for the observed injection and ejection probabilities of electrons. A simple tunneling model, incorporating the voids, explains the strongly reduced injection currents from Al whereas the top electrode fabricated by vapor deposition of Au onto the nanoparticle topology adopts the inverse ZnO(NP) morphology leading to enlarged injection areas combined with Au-tip landscapes. These tips in contrast to the smooth sputtered ZnO(SP) lead to electric field enhancement and strongly increased injection of electrons in reverse direction. The injected charge piles up at the barrier generated by voids between ZnO(NP) and the bottom electrode forcing a change in the barrier shape and therefore allowing for higher ejection rates. Both effects in combination explain the inverse I-V characteristic of nanoparticle based diodes.

  14. Toxic erythema of chemotherapy following i.v. BU plus fludarabine for allogeneic PBSC transplant.

    Science.gov (United States)

    Parker, T L; Cooper, D L; Seropian, S E; Bolognia, J L

    2013-05-01

    I.v. BU plus fludarabine is an effective conditioning regimen for myeloid neoplasias with low treatment-related mortality. At standard doses, cutaneous toxicity has been reported in <5% of cases. As we observed a much higher incidence of cutaneous toxicity in patients who received predominantly pharmacokinetically based doses of BU, we performed a retrospective analysis of 61 patients who received i.v. BU plus fludarabine (+/- antithymocyte globulin; ATG) as a conditioning regimen before allogeneic PBSC transplant. Of the 58 evaluable patients, 33 (57%) developed cutaneous toxicity that fell within the spectrum of toxic erythema of chemotherapy (TEC). The median onset of TEC was 22 days and most patients had multiple sites of involvement, with the groin, axillae and palms/soles being the favored sites. In men, scrotal involvement, sometimes severe, was also commonly observed. Initially, allergic reactions to antibiotics, fungal infections and GVHD were also considered until the clinical presentation of TEC became well recognized. In all patients, the skin healed without specific therapy but resolution often required several weeks. This series suggests that TEC is common after BU/fludarabine+/- ATG and it is important for transplant physicians to recognize, particularly as misdiagnosis could lead to inappropriate treatment.

  15. Effects of Unintended Dopants on I-V Characteristics of the Double-Gate MOSFETs,a Simulation Study

    Institute of Scientific and Technical Information of China (English)

    李佩成; 梅光辉; 胡光喜; 王伶俐; 刘冉; 汤庭鳌

    2012-01-01

    In this paper, we study the effects of an unintended dopant in the channel on the current-voltage char-acteristics of a Double-Gate (DG) Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). Non-Equilibrium Green's Function (NEGF) approach is used. A quantum transport model to calculate the drain current is presented and subthreshold swing and drain induced barrier lowering (DIBL) effect are studied.

  16. Preparation of n-ZnO/p-CuO Coaxial Nanocable Heterojunction and Its I-V Characteristic%n-ZnO/p-CuO同轴纳米线异质结的制备及其I-V特性

    Institute of Scientific and Technical Information of China (English)

    彭伟; 李金钗

    2013-01-01

    n-ZnO/p-CuO coaxial nanocable heterojunctions were fabricated b' a t (o)-step method.The ZnO nanowires were first synthesized on silicon(100) substrates via a thermal vapor deposition route.Then the CuO shells with uniform,intensive and ultrafine CuO nanoparticles were prepared on the surfaces of ZnO nanowires using the ion beam sputtering technology combining thermal oxidation process.Scanning electron microscopy (SEM),X-ray diffraction (XRD),transmission electron microscopy(TEM)and high-resolution transmission electron microscopy (HR-TEM) were used to study the morphology,composition and crystal structure of ZnO/CuO samples.The results indicate that the grown ZnO nanowires have Wurtzite single-crystalline structure and the CuO nanoshells display polycrystalline structure.The current-voltage (I-V) measurement based on the n-ZnO/p-CuO hetrojunctions showed an excellent typical semiconductor rectification characteristic.The n-ZnO/p-CuO coaxial nanocable heterojunctions,with large heterojunction area,large light illumination surface area and strong surface chemical activity,have promising applications in the fields of nano-rectifiers with high current density,solar cells,photosensitive devices and gas sensors.%采用热蒸发气相沉积法在Si(100)衬底上生长直径约为60~70 nm的氧化锌(ZnO)纳米线,迸一步运用离子束溅射技术和热氧化工艺在ZnO纳米线表面形成含有均匀密集分布的超细氧化铜(CuO)纳米颗粒的CuO壳层,构成n-ZnO(核芯)/p-CuO(壳层)同轴纳米线异质结.扫描电子显微镜(SEM)、X射线衍射(XRD)、透射电子显微镜(TEM)和高分辨透射电子显微镜(HRTEM)用于研究样品的形貌、成分和晶体结构.实验结果表明,生长的ZnO纳米线呈纤锌矿单晶结构,CuO壳层为多晶结构.I-V曲线表明该同轴纳米线异质结构具有优良的二极管整流特性.这种具有大的异质结面积和高的比表面受光面积及强的表面化学活性的n-ZnO/p-CuO同轴纳

  17. 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.

  18. Distribution of i.v. administered epidermal growth factor in the rat

    DEFF Research Database (Denmark)

    Poulsen, Steen Seier; Nexø, Ebba

    1988-01-01

    The distribution of i.v. injected 125I-labeled epidermal growth factor (EGF) was examined in the rat. The uptake of radioactivity was examined for the following tissues: liver, kidney, skin, stomach, small intestine, colon, brain, submandibular gland, lung, spleen, and testis. 125I-EGF was cleared...... of 125I-EGF per g tissue was markedly higher for the liver and kidneys than for the rest of the organs. By autoradiography 125I-EGF was found in the peripheral parts of the classical liver lobule, in the proximal tubules of the kidneys, in the surface epithelium of the stomach, and in the surface...... epithelium of the villi in the small intestine. In conclusion the present study showed that small doses of homologous EGF was cleared from the circulation of rats within minutes, mainly by the liver, the kidneys, and the small intestine....

  19. The effect of gradually constricted channel on the I-V characteristics of graphene sheets

    Science.gov (United States)

    Zanella, Fernando; Nobrega, K. Z.; Dartora, C. A.

    2016-10-01

    Ideal graphene is a gapless semiconductor consisting of a single layer of carbon atoms regularly arranged in a honeycomb lattice having infinite spatial extent in the (x,y)-plane, in which electrons behave as Dirac massless fermions. Even neglecting interactions with the anchoring substrate, a graphene sheet in real world has finite extent, leading to distinctive features in the conductivity of a given sample. In this letter we study the effect of a gradual channel constriction in graphene nanoribbons on their I-V characteristics, using non-equilibrium Green's function formalism. The constriction width and the border cutting angle are the main parameters to be varied. We found that transmission through the channel is considerably affected by these parameters, presenting sharp peaks at specific energies, which can be attributed to a resonance due to the tuning of energy eigenvalues.

  20. Immunolocalisation pattern of complex I-V in ageing human retina: Correlation with mitochondrial ultrastructure.

    Science.gov (United States)

    Nag, Tapas Chandra; Wadhwa, Shashi

    2016-11-01

    Earlier studies reported accumulation of mitochondrial DNA mutations in ageing and age-related macular degeneration. To know about the mitochondrial status with age, we examined immunoreactivity (IR) to markers of mitochondria (anti-mitochondrial antibody and voltage-dependent anion channel-1) and complex I-V (that mediate oxidative phosphorylation, OXPHOS) in donor human retinas (age: 19-94years; N=26; right eyes). In all samples, at all ages, IR to anti-mitochondrial antibody and voltage-dependent anion channel-1 was prominent in photoreceptor cells. Between second and seventh decade of life, strong IR to complex I-V was present in photoreceptors over macular to peripheral retina. With progressive ageing, the photoreceptors showed a decrease in complex I-IR (subunit NDUFB4) at eighth decade, and a weak or absence of IR in 10 retinas between ninth and tenth decade. Patchy IR to complex III and complex IV was detected at different ages. IR to ND1 (complex I) and complex II and V remained unaltered with ageing. Nitrosative stress (evaluated by IR to a nitro-tyrosine antibody) was found in photoreceptors. Superoxide dismutase-2 was found upregulated in photoreceptors with ageing. Mitochondrial ultrastructure was examined in two young retinas with intact complex IR and six aged retinas whose counterparts showed weak to absence of IR. Observations revealed irregular, photoreceptor inner segment mitochondria in aged maculae and mid-peripheral retina between eighth and ninth decade; many cones possessed autophagosomes with damaged mitochondria, indicating age-related alterations. A trend in age-dependent reduction of complex I-IR was evident in aged photoreceptors, whereas patchy complex IV-IR (subunits I and II) was age-independent, suggesting that the former is prone to damage with ageing perhaps due to oxidative stress. These changes in OXPHOS system may influence the energy budget of human photoreceptors, affecting their viability. Copyright © 2016 Elsevier B.V. and

  1. High temperature Hall measurement setup for thin film characterization

    Science.gov (United States)

    Adnane, L.; Gokirmak, A.; Silva, H.

    2016-07-01

    Hall measurement using the van der Pauw technique is a common characterization approach that does not require patterning of contacts. Measurements of the Hall voltage and electrical resistivity lead to the product of carrier mobility and carrier concentration (Hall coefficient) which can be decoupled through transport models. Based on the van der Paw method, we have developed an automated setup for Hall measurements from room temperature to ˜500 °C of semiconducting thin films of a wide resistivity range. The resistivity of the film and Hall coefficient is obtained from multiple current-voltage (I-V) measurements performed using a semiconductor parameter analyzer under applied constant "up," zero, and "down" magnetic field generated with two neodymium permanent magnets. The use of slopes obtained from multiple I-Vs for the three magnetic field conditions offer improved accuracy. Samples are preferred in square shape geometry and can range from 2 mm to 25 mm side length. Example measurements of single-crystal silicon with known doping concentration show the accuracy and reliability of the measurement.

  2. 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

    2017-02-01

    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.

  3. Construction of an X-ray detecting module and its application to relative-sensitivity measurement using a silicon PIN diode in conjunction with short-decay-time scintillators

    Science.gov (United States)

    Nihei, Shinichi; Sato, Eiichi; Hamaya, Tatsuki; Numahata, Wataru; Kogita, Hayato; Kami, Syouta; Arakawa, Yumeka; Oda, Yasuyuki; Hagiwara, Osahiko; Matsukiyo, Hiroshi; Osawa, Akihiro; Enomoto, Toshiyuki; Watanabe, Manabu; Kusachi, Shinya

    2014-12-01

    To detect low-dose-rate X-rays, we have developed an X-ray-detecting module for semiconductor diodes. The module consists of a current-voltage (I-V) amplifier, a voltage-voltage (V-V) amplifier, and an alternating-current adopter with a smoothing circuit. The photocurrents flowing through a diode are converted into voltages and amplified using the I-V and V-V amplifiers. To measure relative sensitivities, we used three silicon PIN diodes (Si-PIN), a cerium-doped yttrium aluminum perovskite [YAP(Ce)] crystal, and a Lu2(SiO4)O [LSO] crystal. Three detectors are as follows: an Si-PIN, a YAP(Ce)-Si-PIN, and an LSO-Si-PIN. Using the three detectors, the amplifier output voltages were in proportion to the tube current at a constant tube voltage of 70 kV. Using a multichannel analyzer, the event-pulse-height spectra were measured to analyze X-ray-electric conversion effect in the three detectors. The output voltage of the Si-PIN was approximately twice as high as those obtained using the YAP(Ce)-Si-PIN and the LSO-Si-PIN at the measurement conditions.

  4. First-principle studies of I-V properties of a molecular wire

    Institute of Scientific and Technical Information of China (English)

    王传奎; 李红海; 李英德; 罗毅; 付英

    2003-01-01

    The elastic scattering Green function method has been developed to describe the I-V characteristics of molecular wires. The molecular electronic structure and the interaction between the molecule and the gold surface are two key factors for the charge transport properties of molecular wires in the formulas. An ab initio calculation at the hybrid density functional theory level is carried out to obtain the electronic structure of 4-4′-dimercaptodibenzene molecule. The frontier orbit theory and the perturbation theory are employed to determine the constant of the interaction energy between molecule and surface quantitatively. The numerical results show that the bonding between the sulfur atom and the gold atoms corresponds mainly to the covalent bond. Some molecular orbits are extended over molecule and gold cluster that certainly give channels for the charge transport, other molecular orbits are localized and the charge transport can take place by tunnel mechanism. At zero bias region, there exists a current gap. With the increasing bias, the conductance of the wire takes a shape of plateaus.

  5. 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.

  6. A method for the determination of the standard deviations of the solar cell I-V characteristic parameters

    Energy Technology Data Exchange (ETDEWEB)

    Veissid, N. (Instituto de Pesquisas Espaciais, Sao Jose dos Campos (Brazil)); Cruz, M.T.F. da (Universidade de Sao Paulo, SP (Brazil). Inst. de Fisica); Andrade, A.M. de (Universidade de Sao Paulo, SP (Brazil). Lab. de Microeletronica)

    1990-05-01

    A method for the determination of the standard deviations of the solar cell characteristic curve fitting parameters is presented for the first time. In this method, a Taylor series expansion of the parameters, around their best values, is made resulting in linear functions which permit the determination of the standard deviations with the least-squares method. The parameters, with the respective standard deviations, were determined from the experimental I-V characteristic curves obtained under illuminated and dark conditions. For the studied experimental I-V curves, the diode saturation currents, the diode factor and the shunt resistance showed smaller standard deviations in the dark condition, and the series resistance appeared to be more precise in the illuminated I-V characteristic. (orig.).

  7. 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.

  8. Study of current-voltage characteristics of ferromagnetic α-Fe{sub 1.64}Ga{sub 0.36}O{sub 3} oxide under magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Vijayasri, G., E-mail: vsvijiguna.physics@gmail.com; Bhowmik, R. N. [Department of Physics, Pondicherry University, R..Venkataraman Nagar, Kalapet, Puducherry – 605 014 (India)

    2015-06-24

    We report the influence of magnetic field on I-V characteristics of α-Fe{sub 1.64}Ga{sub 0.36}O{sub 3} sample. Synchrotron X-ray diffraction pattern and Raman Spectroscopy have confirmed rhombohedral structure with space group R3C in the sample. The sample exhibits ferromagnetic feature at room temperature and non saturation of magnetization up to 7Tesla suggests the effect of non-collinear structure (canting) of the spins on the ferromagnetic properties. We have recorded I-V characteristics of the sample under magnetic field to study the effect of non-collinear spin structure on the electrical properties. Space charge limited current mechanism controlled the nature of non-linear I-V curves and the curves are significantly affected by magnetic field.

  9. Charge carrier transport in Cu(In,Ga)Se{sub 2} thin-film solar-cells studied by electron beam induced current and temperature and illumination dependent current voltage analysis

    Energy Technology Data Exchange (ETDEWEB)

    Nichterwitz, Melanie

    2012-01-10

    This work contributes to the understanding of generation dependent charge-carrier transport properties in Cu(In,Ga)Se{sub 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{sub 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{sup +} 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{sup +} layer at the CIGSe/CdS interface and acceptor type defect states at the CdS/ZnO interface

  10. Investigation of electric charge transport in conjugated polymer P3HT: PCBM solar cell with temperature dependent current and capacitance measurements

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Peiqing; Mencaraglia, Denis; Darga, Arouna; Migan, Anne [Laboratoire de Genie Electrique de Paris, CNRS UMR 8507, SUPELEC, UPMC, Universite Paris VI, Universite Paris-Sud, 11 Rue Joliot Curie, Plateau de Moulon, 91192 Gif-Sur-Yvette Cedex (France); Rabdbeh, Roshanak; Ratier, Bernard; Moliton, Andre [Institut Carnot XLim, UMR 6172, CNRS, Universite de Limoges, 123 Avenue Albert Thomas, 87060 Limoges Cedex (France)

    2010-04-15

    We investigated quantitatively the electronic transport properties of a bulk heterojunction polymer/fullerene solar cell, based on structure Glass/ITO/P3HT:PCBM/Al. The current-voltage I-V characteristics in the intermediate positive bias and temperature regime (0.2 V {<=} V {<=} 1.5 V, 180 K {<=} T {<=} 250 K) can be well fitted by a modified Poole-Frenkel PF detrapping model. Combining these results with the high frequency capacitance measurements, we could then derive independently the absorber thickness and its dielectric constant. At low temperature (80 K {<=} T {<=} 170 K), the I-V data can be well accounted for with Space Charge Limited Current (SCLC) regimes. At intermediate positive bias (1 V {<=} V {<=} 2.3 V), the current is dominated by the trapped space charges with an exponential traps distribution, while at high positive bias (2.5 V {<=} V {<=} 4 V), the space charges due to injected free carrier play an important role for the conduction. From the fits to the two different SCLC models, we could then extract the electrically active defects parameters controlling the transport. These parameters were confirmed by space charge capacitance spectroscopy (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Verification of risk scores to predict i.v. immunoglobulin resistance in incomplete Kawasaki disease.

    Science.gov (United States)

    Kanamitsu, Kiichiro; Kakimoto, Hisako; Shimada, Akira; Nakata, Yusei; Ochi, Hiroaki; Watanabe, Hirokazu; Iwasaki, Yuka; Tokorodani, Chiho; Kanazawa, Akane; Maruyama, Hidehiko; Miyazawa, Mari; Nishiuchi, Ritsuo; Kikkawa, Kiyoshi

    2016-02-01

    A recent study indicated the efficacy of the addition of prednisolone to i.v. immunoglobulin (IVIG) as initial treatment in patients with higher risk of IVIG resistance. Several different risk scores for predicting IVIG resistance have been proposed, mainly based on typical Kawasaki disease (KD) patients. We investigated the utility of the risk scores to predict IVIG resistance in incomplete KD. Clinical records of incomplete KD patients who received a single dose of IVIG between 2005 and 2012 at Kochi Health Sciences Center were retrospectively reviewed. Patients were classified into an IVIG-responsive group and an IVIG-resistant group. The Kobayashi, Egami, and Sano risk scores were calculated for each patient and the proportion of high-risk patients was compared between the two groups for each risk score. For 51 incomplete KD patients, Kobayashi (66.7% vs 47.6%, P = 0.253), Egami (55.6% vs 38.1%, P = 0.274), and Sano (57.1% vs 10.8%, P = 0.068) risk scores identified a higher proportion of high-risk patients in the IVIG-resistant group compared with the IVIG-responsive group, but significant difference was not observed. Sano risk score had the highest OR (6.19; 95%CI: 1.00-38.26). The proportion of patients identified as being at high risk for IVIG resistance using the Kobayashi, Egami, and Sano risk scores, respectively, was not significantly different between the IVIG-responsive group and the IVIG-resistant group for incomplete KD. Among the three risk scores, the Sano risk score has the best ability to predict IVIG resistance in incomplete KD. © 2015 Japan Pediatric Society.

  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. Study of carrier energetics in ITO/P(VDF-TrFE)/pentacene/Au diode by using electric-field-induced optical second harmonic generation measurement and charge modulation spectroscopy

    Science.gov (United States)

    Otsuka, Takako; Taguchi, Dai; Manaka, Takaaki; Iwamoto, Mitsumasa

    2017-02-01

    By using electric-field-induced optical second harmonic generation (EFISHG) measurement and charge modulation spectroscopy (CMS), we studied carrier behavior and polarization reversal in ITO/ poly(vinylidene fluoride trifluoroethylene) (P(VDF-TrFE))/pentacene/Au diodes with a ferroelectric P(VDF-TrFE) layer in terms of carrier energetics. The current-voltage (I-V) characteristics of the diodes showed three-step polarization reversal in the dark. However, the I-V was totally different under illumination and exhibited two-step behavior. EFISHG probed the internal electric field in the pentacene layer and accounted for the polarization reversal change due to charge accumulation at the pentacene/P(VDF-TrFE) interface. CMS probed the related carrier energetics and indicated that exciton dissociation in pentacene molecular states governed carrier accumulation at the pentacene/ferroelectric interface, leading to different polarization reversal processes in the dark and under light illumination. Combining EFISHG measurement and CMS provides us a way to study carrier energetics that govern polarization reversal in ferroelectric P(VDF-TrFE)/pentacene diodes.

  14. Explorations of new second-order nonlinear optical materials in the K(I)-M(II)-I(V)-O systems.

    Science.gov (United States)

    Li, Pei-Xin; Hu, Chun-Li; Xu, Xiang; Wang, Rui-Yao; Sun, Chuan-Fu; Mao, Jiang-Gao

    2010-05-17

    Explorations of new second-order nonlinear optical (NLO) materials in the K(I)-M(II) -I(V)-O systems led to four novel mixed metal iodates, namely, K(2)M(IO(3))(4)(H(2)O)(2) (M = Mn, Co, Zn, Mg). The four compounds are isostructural and crystallize in space group I2 which is in the chiral and polar crystal class 2. Their structure features zero-dimensional {M(IO(3))(4)(H(2)O)(2)}(2-) anions that are separated by K(+) cations. The M(II) centers are ligated by two aqua ligands in trans fashion and four monodentate iodate anions. The K(+) cation is eight-coordinated by two iodate anions in bidentate chelating fashion and four other iodates in a unidentate fashion. Second harmonic generation (SHG) measurements indicate that K(2)Zn(IO(3))(4)(H(2)O)(2) and K(2)Mg(IO(3))(4)(H(2)O)(2) display moderate SHG responses that are approximately 2.3 and 1.4 times of KH(2)PO(4) (KDP), respectively, and they are also phase-matchable. The SHG response of K(2)Co(IO(3))(4)(H(2)O)(2) is much weaker (about 0.3 x KDP), and no obvious SHG signal was detected for K(2)Mn(IO(3))(4)(H(2)O)(2). Results of optical property calculations for the Zn and Mg phases revealed SHG responses of approximately 5.3 and 4.7 times of KDP, respectively, the order of Zn > Mg is in good agreement with the experiment data.

  15. Effect of illumination intensity and temperature on the I-V characteristics of n-C/p-Si heterojunction

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Babita; Shishodia, P.K.; Kapoor, A.; Mehra, R.M. [Department of Electronic Science, University of Delhi South Campus, Benito Juarez Road, 110021 New Delhi (India); Soga, Tetsuo; Jimbo, Takashi [Department of Environmental Technology and Urban Planning, Nagoya Institute of Technology, 466-8555 Nagoya (Japan); Umeno, Masayoshi [Research Center for Microstructure Devices, Nagoya Institute of Technology, 466-8555 Nagoya (Japan)

    2002-07-01

    Krishna et al. (Sol. Energy Mater. Sol. Cells 65 (2001) 163) have recently developed an heterojunction n-C/p-Si in order to achieve low cost and high-efficiency carbon solar cell. It has been shown that for this structure, the maximum quantum efficiency (25%) appears at wavelength {lambda} (600nm). In this paper, the dependence of I-V characteristics of this heterojunction solar cell on illumination intensity and temperature has been systematically investigated. An estimation of the stability of the solar cell with temperature has been made in terms of the temperature coefficient of I{sub sc} and V{sub oc}. The intensity variation study has been used to estimate the series resistance R{sub s} of the solar cell. The effect of illumination intensity on I-V of n-C/p-Si heterojunction is more complex because the carrier lifetime and the carrier mobility of amorphous carbon are small and also because drift of carriers by built-in electric field plays an important role in these cells. Therefore, the conventional analytical expression for I-V characteristic is not applicable to such solar cells. These structures will not obey the principle of superposition of illuminated and dark current. The experimental results have been analysed by developing empirical relation for I-V.The temperature sensitivity parameters {alpha}, the change in I{sub sc} and {beta}, the change in V{sub oc} per degree centigrade have been computed and are found to be 0.087mA/C and 1mV/C, respectively. This suggests that the heterojunction n-C/p-Si has good temperature tolerance. The value of series resistance has been estimated from the family of I-V curves at various intensities. The R{sub s} is found to be {approx}12{omega}, which is on the higher side from the point of view of photovoltaic application.

  16. 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.

  17. 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.

  18. 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.

  19. 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.

    Directory of Open Access Journals (Sweden)

    Kristin Lees

    Full Text Available 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.

  20. Enhanced Magnetic and Ferroelectric Properties and Current-Voltage Hysteresis by Addition of La and Ti to BiFeO3 on 0.7%Nb-SrTiO3

    Institute of Scientific and Technical Information of China (English)

    CHANG Hong; ZHAO Yong-Gang

    2011-01-01

    By adding La and Ti, we improve the magnetic and ferroelectric properties of BiQ.sLa0.2Feo.g2Ti0.08O3 and Bio.sLa0.2FeO3 Rims on 0.7%Nb-SrTiO3. In Bio.8La0.2Feo.92Ti0.08O3 and Bio.sLa0.2FeOa, the saturation magnetization and the coercivity are several times higher than those in BiFeO3. The La and Ti additions reduce the leakage current, and increase the remnant electric polarization. A resistance switching is observed in Bio.8Lao.2Feo.92Tio.o803/0.7%Nb-SrTi03 and Bi0.8La0.2FeO3/0.7%Nb-SrTiO3 interfaces. Also, it is observed that Bio.sLao.2Feo.92 Ti0.08O3/0.7%Nb-SrTiO3 has a wider current-voltage hysteresis and a larger resistance difference than Bi0.sLao.2Fe03/0.7%Nb-SrTi03. In the interface of Bi0.8Lao.2Fe0.92Ti0.08 O3/0.7%JVb-SrTiO3, the ratio of high to low resistance is 103 and 105 times, at 300K and 10 K, respectively. The voltage pulses can switch the resistance to vary in the 2 states. The transport mechanisms show that a trap-controlled space-charge-limited current induces current-voltage hysteresis and resistance switching. The current of Bio.8Lao.2Feo.g2 Tio.os O3/0.7%Nb-SrTiO3 decays with the Curie-Von Schweidler law.%@@ By adding La and Ti, we improve the magnetic and ferroelectric properties of BiLaFeTiO and BiLaFeO films on 0.7%Nb-SrTiO.In BiLaFeTiO and BiLaFeO, the saturation mag- netization and the coercivity are several times higher than those in BiFeO.The La and Ti additions re- duce the leakage current, and increase the remnant electric polarization.A resistance switching is observed in BiLaFe TiO/0.7%Nb-SrTiO and BiLaFeO/0.7%Nb-SrTiO interfaces.Also, it is observed that BiLaFe TiO/0.7%Nb-SrTiO has a wider current-voltage hysteresis and a larger resistance differ- ence than BiLaFeO/0.7%Nb-SrTiO.In the interface of BiLaFeTiO/0.7%Nb-SrTiO, the ratio of high to low resistance is 10 and 10 times, at 300 K and 10K, respectively.The voltage pulses can switch the resistance to vary in the 2 states.The transport mechanisms show that a trap

  1. High temperature behavior of multi-region direct current current-voltage spectroscopy and relationship with shallow-trench-isolation-based high-voltage laterally diffused metal-oxide-semiconductor field-effect-transistors reliability

    Science.gov (United States)

    He, Yandong; Zhang, Ganggang; Zhang, Xing

    2014-01-01

    With the process compatibility with the mainstream standard complementary metal-oxide-semiconductor (CMOS), shallow trench isolation (STI) based laterally diffused metal-oxide-semiconductor (LDMOS) devices have become popular for its better tradeoff between breakdown voltage and performance, especially for smart power applications. A multi-region direct current current-voltage (MR-DCIV) technique with spectroscopic features was demonstrated to map the interface state generation in the channel, accumulation and STI drift regions. High temperature behavior of MR-DCIV spectroscopy was analyzed and a physical model was verified. Degradation of STI-based LDMOS transistors under high temperature reverse bias (HTRB) stress is experimentally studied by MR-DCIV spectroscopy. The impact of interface state location on device electrical characteristics was investigated. Our results show that the major contribution to HTRB degradation, in term of the on-resistance degradation, was attributed to interface state generation under STI drift region.

  2. The current-voltage characteristics of polymer/C60 diodes in the dark: A direct way to assess photovoltaic devices efficiency parameters

    Science.gov (United States)

    Koehler, M.; Yamamoto, N. A. D.; Macedo, A. G.; Grodniski, D. Z.; Roman, L. S.; da Luz, M. G. E.

    2013-07-01

    A general description of dark transport properties in bi-layer organic photovoltaic devices formed by a heterojunction of a semiconducting co-polymer and fullerene (C60) is presented. The copolymers are composed of thiophene, phenylene, and fluorene units, where the thiophene content is kept constant while the fluorene/phenylene ratio is varied. Measurements show that the j × V characteristics display typical diode behavior (exponential increasing) at low and are space-charge limited at high voltages. Extending a theoretical analysis by Koehler et al. [J. Appl. Phys. 92, 5575 (2002)], a model which assumes a space-charge dependent inner series resistance—attributed to molecular and morphological aspects of the materials—is proposed. It turns out to be general and able to nicely fit the experimental curves for all the studied samples. Furthermore, the model quantifies relevant parameters (the effective mobility and the diode reverse saturation current j0) which will determine the systems efficiency. The framework hence allows to foremost the devices functioning under illumination from direct experiments of the active material in the dark.

  3. Real-Time Series Resistance Monitoring in PV Systems Without the Need for I-V Curves

    Energy Technology Data Exchange (ETDEWEB)

    Deceglie, Michael G. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Silverman, Timothy J. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Marion, Bill [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kurtz, Sarah R. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-10-01

    We apply the physical principles of a familiar method, suns-Voc, to a new application: the real-time detection of series resistance changes in modules and systems operating outside. The real-time series resistance (RTSR) method that we describe avoids the need for collecting I-V curves or constructing full series resistance-free I-V curves. RTSR is most readily deployable at the module level on microinverters or module-integrated electronics, but it can also be extended to full strings. We found that automated detection of series resistance increases can provide early warnings of some of the most common reliability issues, which also pose fire risks, including broken ribbons, broken solder bonds, and contact problems in the junction or combiner box. We also describe the method in detail and describe a sample application to data collected from modules operating in the field.

  4. Chemical input and I-V output: stepwise chemical information processing in dye-sensitized solar cells.

    Science.gov (United States)

    Satoh, Norifusa; Han, Liyuan

    2012-12-14

    As a complex system, a dye-sensitized solar cell (DSC) exhibits emergent photovoltaics not obvious from the properties of the individual components. The chemical input of 4-tert-butylpyridine (TBP) into DSC improves the open circuit voltage (V(oc)) and reduces the short circuit current (I(sc)) in I-V output through multiple interactions with the components, yet it has been difficult to distinguish the multiple interactions and correlate the interactions with the influences on I-V output due to the complexity of the system. To deal with the multiple interactions, we have adapted a conceptual framework and methodology from coordination chemistry. First, we titrated the photovoltaic interface and electrolyte with TBP to identify the stepwise chemical interaction processes. An isopotential point observed in I-V output indicates that most of the inputted chemicals interact with the electrolyte. Cyclic voltammetric titration of the electrolyte demonstrates asymmetric redox peaks and two different isopotential points, indicating that the two-step coordination-decoordination process inhibits the reduction current of the electrolyte. Second, we set an interaction model bridging the hierarchical gaps between the multiple interactions and the I-V output to address the influences on outputs from the amount of the inputs. From the viewpoint of the interaction model and interactions observed, we are able to comprehend the processes of the complex system and suggest a direction to improve V(oc) without sacrificing I(sc) in DSCs. We conclude that the conceptual framework and methodology adapted from coordination chemistry is beneficial to enhance the emergent outputs of complex systems.

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

    CERN Document Server

    Han, Jie; Casey, Tiernan A; Bisetti, Fabrizio; Im, Hong G; Chen, Jyh-Yuan

    2016-01-01

    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-V curve 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 agre...

  6. I.v. N-acetylcysteine and emergency CT: use of serum creatinine and cystatin C as markers of radiocontrast nephrotoxicity.

    Science.gov (United States)

    Poletti, Pierre-Alexandre; Saudan, Patrick; Platon, Alexandra; Mermillod, Bernadette; Sautter, Anna-Maria; Vermeulen, Bernard; Sarasin, François P; Becker, Christoph D; Martin, Pierre-Yves

    2007-09-01

    The purpose of this study was to assess the effect of i.v. administration of N-acetylcysteine (NAC) on serum levels of creatinine and cystatin C, two markers of renal function, in patients with renal insufficiency who undergo emergency contrast-enhanced CT. Eighty-seven adult patients with renal insufficiency who underwent emergency CT were randomized to two groups. In the first group, in addition to hydration, patients received a 900-mg injection of NAC 1 hour before and another immediately after injection of iodine contrast medium. Patients in the second group received hydration only. Serum levels of creatinine and cystatin C were measured at admission and on days 2 and 4 after CT. Nephrotoxicity was defined as a 25% or greater increase in serum creatinine or cystatin C concentration from baseline value. A 25% or greater increase in serum creatinine concentration was found in nine (21%) of 43 patients in the control group and in two (5%) of 44 patients in the NAC group (p = 0.026). A 25% or greater increase in serum cystatin C concentration was found in nine (22%) of 40 patients in the control group and in seven (17%) of 41 patients in the NAC group (p = 0.59). On the basis of serum creatinine concentration only, i.v. administration of NAC appears protective against the nephrotoxicity of contrast medium. No effect is found when serum cystatin C concentration is used to assess renal function. The effect of NAC on serum creatinine level remains unclear and may not be related to a renoprotective action.

  7. Theoretical method for estimation of power loss due to mismatch in solar cell I-V characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Srinivasamurthy, N.; Malathi, B.; Mathur, R.S.

    1978-01-01

    In order to generate power from the solar panels at a required voltage, suitable number of cells should be connected in series and parallel. There exists a mismatch in the solar cell I-V characteristics, when they are produced in a lot. When such cells are connected in a series parallel array, power loss would occur due to the mismatch. A theoretical approach is made to compute the power loss. This would suggest the designer to select proper combination of cells for minimum power loss of any configuration of the solar panel.

  8. 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.

  9. 二极管特性简化模型在染料敏化太阳能电池电流-电压曲线拟合及在光电特性参数评估中的应用%Application of a Simplified Diode Characteristic Model in Current-Voltage Curve Fitting and Evaluation of Photoelectric Parameters within Dye-Sensitized Solar Cell

    Institute of Scientific and Technical Information of China (English)

    张平; 王弋; 付立民; 艾希成; 张建平

    2015-01-01

    In the present work, we investigated the dynamics of charge col ection and recombination in dye-sensitized solar cel s (DSSCs) spanning a large region of bias voltages using transient photoconductivity. The rate of charge col ection was much faster than that of charge recombination at varied voltages, which was responsible for the nearly uniform charge col ection efficiency. Based on this result, we simplified the diode characteristic model, which al owed us to directly fit the current-voltage (I-V) curve. A series of parameters related to the photo-to-electric processes in working DSSCs could be extracted from the proposed model, which could be used to evaluate the processes of charge generation, transport, and recombination in DSSCs, as wel as the rectification of DSSC devices. We applied the fitting method to DSSCs with different 4-tert-butyl pyridine (TBP) concentrations of electrolyte. It was found that the rate of charge recombination significantly differed while that of charge col ection was rather constant under different TBP concentrations, which was in good agreement with the results of I-V curve fitting. In addition, this research shows that the change of TBP concentration significantly affects the ideality factor (m) of DSSC devices.%利用瞬态光电导技术研究了在一个大的偏压范围内染料敏化太阳能电池(DSSC)中的电荷收集和电荷复合过程的动力学。结果表明,在不同的电压下电荷收集速率远快于电荷复合速率,用以解释电荷的收集效率几乎不变。基于这个结果,简化了DSSC二极管特性模型,从而实现了对电流-电压(I-V)曲线的直接拟合。利用这一模型拟合的结果提取出一系列与工作条件下DSSC光电转化过程相关的参数,可以用以描述包括电荷生成、电荷收集和复合以及DSSC器件的整流特性等关键性质。将这一拟合方法应用于不同叔丁基吡啶(TBP)浓度电解液的电池,获得的结果表明

  10. Improved treatment of the strongly varying slope in fitting solar cell I-V curves

    Energy Technology Data Exchange (ETDEWEB)

    Burgers, A.R.; Eikelboom, J.A.; Schoenecker, A.; Sinke, W.C.

    1996-05-01

    Straightforward least squares fitting of l-V curves leads to non optimal fits: residuals around and above the open-circuit voltage dominate the fit, leading to a bad fit at the maximum power point and lower voltage values. To deal with this problem, the authors have resorted to using weighting functions or to minimizing the area between data and fit instead of the least squares procedure. Both approaches lack a sound statistical basis. Voltage noise has a big influence on fitting due to the steep slope of an l-V curve for higher voltage values. For this reason the authors have used Orthogonal Distance Regression (ODR), which is a mathematical method for fitting measurements with errors in both voltage- and current measurements. It allows for computing both the l-V curve parameters and their uncertainties. 4 figs., 1 tab., 12 refs.

  11. 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...

  12. Temperature and force dependence of electron transport via the copper protein azurin: conductive probe atomic force microscopy measurements

    CERN Document Server

    Li, Wenjie; Amdursky, Nadav; Cohen, Sidney R; Pecht, Israel; Sheves, Mordechai; Cahen, David

    2012-01-01

    We report conducting probe atomic force microscopy (CP-AFM) measurements of electron transport (ETp), as a function of temperature and force, through monolayers of holo-azurin (holo-Az) and Cu-depleted Az (apo-Az) that retain only their tightly bound water, immobilized on gold surfaces. The changes in CP-AFM current-voltage (I-V) curves for holo-Az and apo-Az, measured between 250 - 370K, are strikingly different. While ETp across holo-Az at low force (6 nN) is temperature-independent over the whole examined range, ETp across apo-Az is thermally activated, with calculated activation energy of 600\\pm100 meV. These results confirm our results of macroscopic contact area ETp measurements via holo- and apo-Az, as a function of temperature, where the crucial role of the Cu redox centre has been observed. While increasing the applied tip force from 6 to 12 nN did not significantly change the temperature dependence of ETp via apo-Az, ETp via holo-Az changed qualitatively, namely from temperature-independent at 6 nN ...

  13. Carrier Lifetimes in a I I I -V -N Intermediate-Band Semiconductor

    Science.gov (United States)

    Heyman, J. N.; Schwartzberg, A. M.; Yu, K. M.; Luce, A. V.; Dubon, O. D.; Kuang, Y. J.; Tu, C. W.; Walukiewicz, W.

    2017-01-01

    We use transient absorption spectroscopy to measure carrier lifetimes in the multiband semiconductor GaPyAs1 -x -yNx . These measurements probe the electron populations in the conduction band, intermediate band, and valence band as a function of time after an excitation pulse. Following photoexcitation of GaP0.32As0.67N0.01 , we find that the electron population in the conduction band decays exponentially with a time constant τCB=23 ps . The electron population in the intermediate band exhibits bimolecular recombination with recombination constant r =2 ×10-8 cm3/s . In our experiment, an optical pump pulse excites electrons from the valence band to the intermediate and conduction bands, and the change in interband absorption due to absorption saturation and induced absorption is probed with a delayed white-light pulse. We model the optical properties of our samples using the band anticrossing model to extract carrier densities as a function of time. These results not only identify the short minority-carrier lifetime as a key factor affecting the performance of GaPyAs1 -x -yNx -based intermediate-band solar cells but also provide guidance on ways to address this issue.

  14. Is routine replacement of i.v. administration sets required after each change of intermittently administrated antibiotic infusions?

    Directory of Open Access Journals (Sweden)

    von Au, Felix

    2013-04-01

    Full Text Available [english] Aim: Manufacturers’ instructions recommend changing the infusion line together with the infusion bottle after each administration. We investigated if the complete infusion line may be microbiologically contaminated after short-time antibiotic and rinse-solution application.Method: Immediately after the change of an infusion administration set after 72 hours the remaining antibiotic solution was inactivated with yolk and cultured on blood agar for 48 hours at 36°C to detect possible contaminants.Results: Among 87 investigated samples no microbial growth was detected. One sample which hadn’t any contact to antibiotics yielded forming unit (cfu of coagulase-negative staphylococci.These results suggest that in case of consecutive antibiotic-short- and rinse-infusions the infusion line may be in place up to 72 hours without contamination. This, however, may be only the case for infusion sets, which are in contact with antibiotics. If no antibiotic is administered, the infusion bottle and the infusion line must be renewed together for every change. To clarify this question into more detail, a larger consecutive study is required. Conclusion: I.v. administration sets without any contact to antibiotics must be changed together with their infusion bottle after administration. In case of consecutive antibiotic-short- and rinse-infusions our pilot study suggests using the i.v. administration sets for up to 72 hours without renewing it at every infusion-set exchange.

  15. Electron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profile

    Science.gov (United States)

    Kumsa, Doe W.; Bhadra, Narendra; Hudak, Eric M.; Kelley, Shawn C.; Untereker, Darrel F.; Mortimer, J. Thomas

    2016-10-01

    The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions. For the engineer/designer this means that if the potential is not in the range of a specific electron transfer process, that process cannot occur. An i(V e) profile, recorded at sweep rates greater than 0.1 mVs-1, approximates steady-state conditions. Rapid transient potential excursions, like that seen with neural stimulation pulses, may be too fast for the reaction to occur, however, this means that if the potential is in the range of a specific electron transfer process it may occur and should be considered. The approach described here can be used to describe the thermodynamic electron transfer processes on other candidate electrode metals, e.g. stainless steel, iridium, carbon-based, etc.

  16. Electron transfer processes occurring on platinum neural stimulating electrodes: a tutorial on the i(V e) profile.

    Science.gov (United States)

    Kumsa, Doe W; Bhadra, Narendra; Hudak, Eric M; Kelley, Shawn C; Untereker, Darrel F; Mortimer, J Thomas

    2016-10-01

    The aim of this tutorial is to encourage members of the neuroprosthesis community to incorporate electron transfer processes into their thinking and provide them with the tools to do so when they design and work with neurostimulating devices. The focus of this article is on platinum because it is the most used electrode metal for devices in commercial use. The i(V e) profile or cyclic voltammogram contains information about electron transfer processes that can occur when the electrode-electrolyte interface, V e, is at a specific potential, and assumed to be near steady-state conditions. For the engineer/designer this means that if the potential is not in the range of a specific electron transfer process, that process cannot occur. An i(V e) profile, recorded at sweep rates greater than 0.1 mVs(-1), approximates steady-state conditions. Rapid transient potential excursions, like that seen with neural stimulation pulses, may be too fast for the reaction to occur, however, this means that if the potential is in the range of a specific electron transfer process it may occur and should be considered. The approach described here can be used to describe the thermodynamic electron transfer processes on other candidate electrode metals, e.g. stainless steel, iridium, carbon-based, etc.

  17. Analysis of the third harmonic for class-F power amplifiers with an I-V knee effect

    Science.gov (United States)

    Zhao, Bo-Chao; Lu, Yang; Wei, Jia-Xing; Dong, Liang; Wang, Yi; Cao, Meng-Yi; Ma, Xiao-Hua; Hao, Yue

    2015-05-01

    The appearance of third-generation semiconductors represented by gallium nitride (GaN) material greatly improves the output power of a power amplifier (PA), but the efficiency of the PA needs to be further improved. The Class-F PA reduces the overlap of drain voltage and current by tuning harmonic impedance so that high efficiency is achieved. This paper begins with the principle of class-F PA, regards the third harmonic voltage as an independent variable, analyzes the influence of the third harmonic on fundamental, and points out how drain efficiency and output power vary with the third harmonic voltage with an I-V knee effect. Finally, the best third harmonic impedance is found mathematically. We compare our results with the Loadpull technique in advanced design system environment and conclude that an optimized third harmonic impedance is open in an ideal case, while it is not at an open point with the I-V knee effect, and the drain efficiency with optimized third harmonic impedance is 4% higher than that with the third harmonic open.

  18. 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.

  19. Effect of π Orbital on I/V Characteristics and Transmission in Molecular Diode Structures with Au Contacts

    Directory of Open Access Journals (Sweden)

    A. Mallaiah

    2017-02-01

    Full Text Available The electronic transport properties of electrons in a molecules are observed by using Non equilibrium Green’s function(NEGF. We present a extremely through and careful computational approach well ordered method to do a framework analysis of donor (CH3 and acceptor (CN molecules connected between the Au(111 contacts, and also observed current progress through molecular devices depends on number of bonds or not. Such observations implementation through not possible by standard quantum chemistry soft wares. The results shows I-V characteristics, Transport spectrum and Transport analysis can effectively tune the molecules works like a conventional semi-conductor based diodes, these results invoke to design the logic gates and logic circuits.

  20. Room-temperature I-V characteristics of a single hollow La₂/₃Ca₁/₃MnO₃ microparticle.

    Science.gov (United States)

    Saleta, M E; Granada, M; Curiale, J; Benavides, R; Troiani, H E; Sánchez, R D

    2011-07-13

    In this work we present an electrical characterization of La₂/₃Ca₁/₃MnO₃ particles obtained by spray pyrolysis. We optimized the synthesis conditions to obtain the desired compound with the expected structure and the ferromagnetic transition at the same temperature as the bulk material. We found that a post-deposition thermal treatment enhances the magnetic properties of the samples. The study of structural, morphological and magnetic properties shows that the walls of the hollow spheres are constituted by grains on the nanometer scale. The I-V characterization shows typical signatures of tunneling transport. This behavior can be associated with the grain boundaries within the microparticle's wall acting as tunnel barriers.

  1. [RAMS academician I. V. Tarasevich is a leader of development of combined inactivated vaccine against Q-fever].

    Science.gov (United States)

    Tokarevich, N K

    2008-01-01

    Short information about significance of Q-fever in human pathology is represented. Necessity of vaccination is proved. The row of vaccines, developed in Czechoslovakia and Romania and identified as small-effective, was considered. Live vaccine from M-44 strain, was made in USSR, still remains in Russia. However, experimental data of American and Russian authors showed persistency of Q-fever agents in vaccinated animals, abortions and other pathology. WHO recommended declining to use live vaccines. Inactivated corpuscular combined vaccine against Q-fever was development under leadership of I. V. Tarasevich. The method of vaccine production is protected by industrial patent #2094057 from 31.01.94, concomitant studies--by 9 author's certificates. The vaccine is harmless, are actogenic, and high immunogenic after single injection. Antibodies of vaccinated persons remain more than in 75% during one year. The vaccine assists in resolving of actual problems of fight against Q-fever.

  2. The influences of the properties of impurities and defects on the dark I-V characteristic curve and output parameters of c-Si solar cells

    Science.gov (United States)

    Lu, Xiaodong; Song, Yang; Gao, Jie; Wang, Xinxin; Zhang, Yufeng

    2017-09-01

    The influences of the coating ratio of electrode, doping concentration of substrate and type of impurities and defects on the dark I-V characteristic curves and output parameters of c-Si solar cells are studied by finite difference method and the dark I-V characteristic curves under different conditions are analyzed by their ideal factors, the results show that: the dark current values under the same bias voltage will increase with the increasing of the coating ratio of electrode or doping concentration of substrate; the influences of donor-like, acceptor-like and recombination-center-like impurities and defects on the dark I-V characteristic curves have threshold effects; the parameters of the impurities and defects smaller than their corresponding threshold will have no obvious influences on dark I-V characteristic curves; the acceptor-like impurities and defects on the surface of c-Si solar cells have no influences on their dark I-V characteristic curve, but the donor-like and recombination-center-like impurities and defects have strong influences on their dark I-V characteristic curve; the variations of the output parameters of c-Si solar cells are analyzed in detail under the different properties of the impurities and defects inside and on the surfaces of c-Si solar cells.

  3. I-V and DLTS study of generation and annihilation of deep-level defects in an oxygen-ion irradiated bipolar junction transistor

    Science.gov (United States)

    Madhu, K. V.; Kulkarni, S. R.; Ravindra, M.; Damle, R.

    A commercial bipolar junction transistor (2N 2219A, npn) irradiated with 84 MeV O6+-ions with fluence of the order of 1013 ions cm-2 is studied for radiation-induced gain degradation and deep-level defects or recombination centers. I-V measurements are made to study the gain degradation as a function of ion fluence. Properties such as activation energy, trap concentration and capture cross section of deep levels are studied by deep-level transient spectroscopy. Minority carrier trap energy levels with energies ranging from EC -0.17 eV to EC -0.55 eV are observed in the base-collector junction of the transistor. Majority carrier defect levels are also observed with energies ranging from EV +0.26 eV to EV +0.44 eV. The irradiated device is subjected to isothermal and isochronal annealing. The defects are seen to anneal above 250 °C. The defects generated in the base region of the transistor by displacement damage appear to be responsible for an increase in base current through Shockley-Read-Hall or multi-phonon recombination and consequent transistor gain degradation.

  4. Analytic current-voltage relationship based on the unified mobility model for organic diodes%有机二极管基于通用迁移率模型的解析电流电压关系

    Institute of Scientific and Technical Information of China (English)

    王平; 孙久勋; 杨凯

    2011-01-01

    An analytical current-voltage relationship is proposed for single-carrier organic light emitting diodes. The model is based on the mobility model of Pasveer et al. [Phys. Rev. Lett. 94 (2005), 206601] that accounts for the most important physical quantities that influence the current transport in organic disordered semiconductors: temperature, carrier concentration, and electric field. The full-analytical formulation is obtained through replacing the constant mobility in Mott-Gurney relationship by the mobility model of Pasveer et al. With carrier concentration and electric field being replaced by their average values evaluated using the strict solutions at constant mobility, and leads to a simple analytical expression. It was validated with experimental data collected from different materials in a wide range of operating conditions.%提出一种有机半导体二极管电流电压关系的解析表达式.该表达式是基于Pasveer等人[Phys.Rev.Lett.94,206601 (2005)]的迁移率模型建立的,其中考虑了影响有机半导体载流子输运最重要的因素,包括温度、载流子浓度和电场强度.将Pasveer等人迁移率公式中的载流子浓度和电场强度用常数迁移率下严格解计算的平均值代入,然后将得到的迁移率取代Mott-Gurney电流电压关系中的常数迁移率从而得到解析电流电压表达式.将新解析表达式应用于三种材料制作的有机二极管,计算结果与实验数据符合很好,表明解析表达式是合理的.

  5. The relationship between the transition voltage of the I- V curve of the ferroelectrics and the coercive field of the P- V hysteretic curve

    Science.gov (United States)

    Xingjiao, Li; Junbo, Bao; Ningzhang, Wang; Jingping, Xu; Tao, Chen; Xuecheng, Zou; Hanhua, Feng; Shaoping, Li

    2002-07-01

    The relationship between the transition voltage of the I- V curve of the ferroelectrics and the coercive field of the P- V hysteretic curve is calculated. The first mathematical analysis to explain the relation between the transition voltage Vt and the coercive voltage Vc is obtained. The origin of the interrelation between the transition voltage of the I- V curve and the coercive field is that the height of the boundary barrier is inversely proportional to the effective dielectric constant of the near-boundary region, which is dependent on a derivative of polarization on the electric field, ∂P/ ∂E. The term ξ( eVt) plus the term ( enb2δ/ dNdPs)( eVc) equals a constant. Vt is the function of Eg, Ps, Vc, and E. There is a linear relation between Vc and Vt. This relationship will induce the matchable relations between the I- V curve and the E- P loop. As long as the Vc of the V- P loop exists, the correspondent Vt of I- V curve will certainly exist. It will be the foundation of a new ferroelectric memory, which operates by the I- V characteristics. These relations are the conditions that can enable nonvolatile memory and nondestructive readout.

  6. Selection of first-line i.v. antibiotics for acute pyelonephritis in patients requiring emergency hospital admission.

    Science.gov (United States)

    Yasufuku, Tomihiko; Shigemura, Katsumi; Yamashita, Masuo; Arakawa, Soichi; Fujisawa, Masato

    2011-04-01

    Febrile urinary tract infections (UTIs) often require the intravenous infusion of antibiotics and/or hospitalization. Acute pyelonephritis (AP) is one of the most severe forms of UTI, and the antibiotics we should use as the first line and the risk factors for treatment failure remain controversial. The objective of this study was to investigate the efficacy of i.v. antibiotics selected for the treatment of febrile AP and to examine the risk factors for antibiotic resistance. We set risk factors for antibiotic treatment failure such as age, sex, and the presence of underlying urinary tract disease. We classified all cases into 49 cases of complicated AP and 24 cases of uncomplicated AP according to the presence of underlying urinary tract diseases, and examined the characteristics of the patients and the efficacy of the antibiotics used in this study. We investigated risk factors which relate to initial treatment failure and the duration of antibiotic treatment. Initial antibiotic treatment failure was significantly correlated to C-reactive protein in complicated AP and to positive blood culture in uncomplicated AP. We revealed a significant correlation between the duration of the given antibiotics and diabetes mellitus or positive blood culture in uncomplicated AP, and tazobactam/piperacillin was significantly related to prolongation of antibiotic treatment in complicated AP. In conclusion, in this study, a positive blood culture was the representative risk factor that related to both initial treatment failure and longer duration of the given antibiotics in uncomplicated AP.

  7. A New Strategy for Accurately Predicting I-V Electrical Characteristics of PV Modules Using a Nonlinear Five-Point Model

    Directory of Open Access Journals (Sweden)

    Sakaros Bogning Dongue

    2013-01-01

    Full Text Available This paper presents the modelling of electrical I-V response of illuminated photovoltaic crystalline modules. As an alternative method to the linear five-parameter model, our strategy uses advantages of a nonlinear analytical five-point model to take into account the effects of nonlinear variations of current with respect to solar irradiance and of voltage with respect to cells temperature. We succeeded in this work to predict with great accuracy the I-V characteristics of monocrystalline shell SP75 and polycrystalline GESOLAR GE-P70 photovoltaic modules. The good comparison of our calculated results to experimental data provided by the modules manufacturers makes it possible to appreciate the contribution of taking into account the nonlinear effect of operating conditions data on I-V characteristics of photovoltaic modules.

  8. 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 based...

  9. The Onomastic Phraseological Units in the Works of I.V. Goethe (Compiled By Authors «German Onomastic Phraseological Dictionary»

    Directory of Open Access Journals (Sweden)

    Manana Napireli

    2015-06-01

    Full Text Available In the given work we’ve got interested in one of the branch of linguistics, onomastics, actually, onomastical phraseology. The research of the onomastical field concerns the proper nouns. This trend of linguistics is very actual in our modern words and attracts much attention. Although, the research of proper nouns comes from the ancient time. The aim of our study is to find those quotes from the works of the greatest representative of German classical literature I.V. Goethe, which possess the proper nouns that became the phraseological units and expressions. The work of I.V. Goethe seems to be very interesting from the point of onomastical phraseology. We’ve revealed 12 onomastical expression; 8 in “Phaust” and 4 in defferent writings.

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

    OpenAIRE

    Anon Namin; Chaya Jivacate; Dhirayut Chenvidhya; Krissanapong Kirtikara; Jutturit Thongpron

    2012-01-01

    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 charac...

  11. 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

  12. Pedal angiography in peripheral arterial occlusive disease: first-pass i.v. contrast-enhanced MR angiography with blood pool contrast medium versus intraarterial digital subtraction angiography.

    Science.gov (United States)

    Kos, Sebastian; Reisinger, Clemens; Aschwanden, Markus; Bongartz, Georg M; Jacob, Augustinus L; Bilecen, Deniz

    2009-03-01

    The purpose of this study was to prospectively evaluate first-pass i.v. gadofosveset-enhanced MR angiography in patients with peripheral arterial occlusive disease for visualization of the pedal arteries and stenosis or occlusion of those arteries with intraarterial digital subtraction angiography as the reference standard. Twenty patients with peripheral arterial occlusive disease (nine women, 11 men; age-range 58-83 years) were prospectively enrolled. Gadofosveset first-pass contrast-enhanced MR angiography was performed with a 1.5-T system, a dedicated foot coil, and cuff compression to the calf. Arterial segments were assessed for degree of arterial stenosis, arterial visibility, diagnostic utility, and venous contamination. Detection of vessel stenosis or occlusion was evaluated in comparison with findings at digital subtraction angiography. The unpaired Student's t test was used to test arterial visibility with the two techniques. First-pass MR angiography with gadofosveset had good diagnostic utility in 83.9% of all segments and no venous contamination in 96.8% of all segments. There was no difference between the performance of intraarterial digital subtraction angiography and that of i.v. contrast-enhanced MR angiography in arterial visibility overall (p = 0.245) or in subgroup analysis of surgical arterial bypass targets (p = 0.202). The overall sensitivity, specificity, and accuracy of i.v. gadofosveset-enhanced MR angiography for characterization of clinically significant stenosis and occlusion were 91.4%, 96.1%, and 93.9%. In the subgroup analysis, the sensitivity, specificity, and accuracy were 85.5%, 96.5%, and 92.1%. Gadofosveset-enhanced MR angiography of the pedal arteries in patients with peripheral arterial occlusive disease has arterial visibility equal to that of digital subtraction angiography and facilitates depiction of clinically significant stenosis and occlusion.

  13. A note on the PT-invariant periodic potential V(x)=4 cos^2 x + 4 i V_0 sin 2x

    CERN Document Server

    Midya, Bikashkali; Roychoudhury, Rajkumar

    2010-01-01

    It is shown that the PT symmetric Hamiltonian with the periodic potential V(x) = 4 cos^2 x + 4 i V_0 sin 2x can be mapped into a Hermitian Hamiltonian for $V_0<0.5$, by a similarity transformation. It is also shown that there exist a second critical point of the potential V(x), apart from the known critical point $V_0=0.5$, for $V_0^c ~ .888437$ after which no part of the eigenvalues and the band structure remains real. Relevant physical consequence of this finding has been pointed out.

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

    DEFF Research Database (Denmark)

    Hansen, Jørn Bindslev; Divin, Yu. Ya.; Mygind, Jesper

    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 L≊(3–5)λJ, where λJ 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....

  15. Adsorption structure determination of a large polyaromatic trithiolate on Cu(111): combination of LEED-I(V) and DFT-vdW.

    Science.gov (United States)

    Sirtl, Thomas; Jelic, Jelena; Meyer, Jörg; Das, Kalpataru; Heckl, Wolfgang M; Moritz, Wolfgang; Rundgren, John; Schmittel, Michael; Reuter, Karsten; Lackinger, Markus

    2013-07-14

    The adsorption geometry of 1,3,5-tris(4-mercaptophenyl)benzene (TMB) on Cu(111) is determined with high precision using two independent methods, experimentally by quantitative low energy electron diffraction (LEED-I(V)) and theoretically by dispersion corrected density functional theory (DFT-vdW). Structural refinement using both methods consistently results in similar adsorption sites and geometries. Thereby a level of confidence is reached that allows deduction of subtle structural details such as molecular deformations or relaxations of copper substrate atoms.

  16. Influence of series resistance and cooling conditions on I-V characteristics of SiC merged PiN Schottky diodes

    Energy Technology Data Exchange (ETDEWEB)

    Hapka, Aneta, E-mail: hapka@ie.tu.koszalin.pl [Department of Electronics and Computer Science, Koszalin University of Technology, J. J. Sniadeckich 2, Koszalin, Postal Code: 75-453 (Poland); Janke, Wlodzimierz; Krasniewski, Jaroslaw [Department of Electronics and Computer Science, Koszalin University of Technology, J. J. Sniadeckich 2, Koszalin, Postal Code: 75-453 (Poland)

    2012-09-01

    The paper presents the exemplary electro-thermal models of merged PiN Schottky diode - a diode with the parallel PiN junction, protecting the device against the uncontrolled voltage rise, causing so-called thermal runaway. In the presented models, the conductivity modulation effect in the PiN junction is taken into account. The influence of the PiN junction on the non-isothermal I-V characteristics of MPS diodes, for various cooling conditions, is discussed. It is shown, that the thermal runaway is possible, in spite of presence of protecting PiN junction.

  17. The Absolute Bioavailability and Effect of Food on the Pharmacokinetics of Odanacatib: A Stable-Label i.v./Oral Study in Healthy Postmenopausal Women.

    Science.gov (United States)

    Zajic, Stefan; Rossenu, Stefaan; Hreniuk, David; Kesisoglou, Filippos; McCrea, Jacqueline; Liu, Fang; Sun, Li; Witter, Rose; Gauthier, Don; Helmy, Roy; Joss, Darrick; Ni, Tong; Stoltz, Randall; Stone, Julie; Stoch, S Aubrey

    2016-09-01

    A stable-label i.v./oral study design was conducted to investigate the pharmacokinetics (PK) of odanacatib. Healthy, postmenopausal women received oral doses of unlabeled odanacatib administered simultaneously with a reference of 1 mg i.v. stable (13)C-labeled odanacatib. The absolute bioavailability of odanacatib was 30% at 50 mg (the phase 3 dose) and 70% at 10 mg, which is consistent with solubility-limited absorption. Odanacatib exposure (area under the curve from zero to infinity) increased by 15% and 63% when 50 mg was administered with low-fat and high-fat meals, respectively. This magnitude of the food effect is unlikely to be clinically important. The volume of distribution was ∼100 liters. The clearance was ∼0.8 l/h (13 ml/min), supporting that odanacatib is a low-extraction ratio drug. Population PK modeling indicated that 88% of individuals had completed absorption of >80% bioavailable drug within 24 hours, with modest additional absorption after 24 hours and periodic fluctuations in plasma concentrations contributing to late values for time to Cmax in some subjects.

  18. Changes in Brain Metallome/Metabolome Pattern due to a Single i.v. Injection of Manganese in Rats

    Science.gov (United States)

    Neth, Katharina; Lucio, Marianna; Walker, Alesia; Zorn, Julia; Schmitt-Kopplin, Philippe; Michalke, Bernhard

    2015-01-01

    Exposure to high concentrations of Manganese (Mn) is known to potentially induce an accumulation in the brain, leading to a Parkinson related disease, called manganism. Versatile mechanisms of Mn-induced brain injury are discussed, with inactivation of mitochondrial defense against oxidative stress being a major one. So far, studies indicate that the main Mn-species entering the brain are low molecular mass (LMM) compounds such as Mn-citrate. Applying a single low dose MnCl2 injection in rats, we observed alterations in Mn-species pattern within the brain by analysis of aqueous brain extracts by size-exclusion chromatography—inductively coupled plasma mass spectrometry (SEC-ICP-MS). Additionally, electrospray ionization—ion cyclotron resonance-Fourier transform-mass spectrometry (ESI-ICR/FT-MS) measurement of methanolic brain extracts revealed a comprehensive analysis of changes in brain metabolisms after the single MnCl2 injection. Major alterations were observed for amino acid, fatty acid, glutathione, glucose and purine/pyrimidine metabolism. The power of this metabolomic approach is the broad and detailed overview of affected brain metabolisms. We also correlated results from the metallomic investigations (Mn concentrations and Mn-species in brain) with the findings from metabolomics. This strategy might help to unravel the role of different Mn-species during Mn-induced alterations in brain metabolism. PMID:26383269

  19. A parameter-free method to extract the superconductor’s J c(B,θ) field-dependence from in-field current-voltage characteristics of high temperature superconductor tapes

    Science.gov (United States)

    Zermeño, Víctor M. R.; Habelok, Krzysztof; Stępień, Mariusz; Grilli, Francesco

    2017-03-01

    The estimation of the critical current (I c) and AC losses of high-temperature superconductor devices through modeling and simulation requires the knowledge of the critical current density (J c) of the superconducting material. This J c is in general not constant and depends both on the magnitude (B loc) and the direction (θ, relative to the tape) of the local magnetic flux density. In principle, J c(B loc,θ) can be obtained from the experimentally measured critical current I c(B a,θ), where B a is the magnitude of the applied magnetic field. However, for applications where the superconducting materials experience a local field that is close to the self-field of an isolated conductor, obtaining J c(B loc,θ) from I c(B a,θ) is not a trivial task. It is necessary to solve an inverse problem to correct for the contribution derived from the self-field. The methods presented in the literature comprise a series of approaches dealing with different degrees of mathematical regularization to fit the parameters of preconceived nonlinear formulas by means of brute force or optimization methods. In this contribution, we present a parameter-free method that provides excellent reproduction of experimental data and requires no human interaction or preconception of the J c dependence with respect to the magnetic field. In particular, it allows going from the experimental data to a ready-to-run J c(B loc,θ) model in a few minutes.

  20. Increase of interleukin-10-producing B cells associated with long-term remission after i.v. immunoglobulin treatment for pemphigus.

    Science.gov (United States)

    Kabuto, Miho; Fujimoto, Noriki; Tanaka, Toshihiro

    2016-07-01

    We present a refractory case of pemphigus vulgaris that achieved long-term remission after i.v. immunoglobulin treatment (IVIG). We evaluated the fluctuation of circulating interleukin-10-producing B cells (B10 cells) during the course in our case and other three patients with pemphigus treated with IVIG without clinical remission. B10 cells were observed predominantly in CD1d(-) , CD5(-) , CD9(-) and CD27(+) populations among CD19(+) cells in healthy controls, as well as in patients with pemphigus. The frequency of B10 cells among CD19(+) cells increased in our case, but not in the other three patients without clinical remission, which leads to speculation on the association between the increase of B10 cells and the achievement of long-term remission after IVIG treatment. © 2016 Japanese Dermatological Association.

  1. Early subclinical rejection treated with low dose i.v. steroids is not associated to graft survival impairment: 13-years' experience at a single center.

    Science.gov (United States)

    Gigliotti, Paolo; Lofaro, Danilo; Leone, Francesca; Papalia, Teresa; Senatore, Massimino; Greco, Rosita; Perri, Anna; Vizza, Donatella; Lupinacci, Simona; Toteda, Giuseppina; La Russa, Antonella; De Stefano, Roberto; Romeo, Francesco; Bonofiglio, Renzo

    2016-06-01

    Subclinical rejection (SCR) has been variably associated with reduced graft survival, development and progression of interstitial fibrosis/tubular atrophy and chronic allograft nephropathy, but data are controversial concerning SCR treatment in terms of graft survival improvement. In this single-center retrospective study, we enrolled 174 adult kidney transplant recipients with a protocol biopsy performed at 30 days after transplantation to evaluate the incidence rate and risk factors for early SCR and its impact on 10-year graft survival. Five patients showed primary non function and were excluded. Among 159/169 (94.08 %) patients with stable graft function who underwent protocol biopsy, 17 (10.7 %) showed signs of SCR and were treated with low-dose intravenous (i.v.) steroids. Ten patients showed functional impairment, 8 (4.73 %) resulting as acute rejection. At multivariate analysis, donor age [odds ratio (OR) 1.04, 95 % confidence interval (CI) 1.01-1.09], and delayed graft function (DGF) (OR 1.08, 95 % CI 1.03-1.12) were significantly associated with SCR. The 10-year graft survival rate in the SCR group was similar to that in the normal-findings group (76.5 vs. 74.9 % respectively; p = 0.61). At multivariate Cox regression, acute [hazard ratio (HR) 5.22, 95 % CI 1.70-16.01], but not sub-clinical, rejection was independently associated with long-term graft failure. In conclusion, early protocol biopsy is a useful and safe tool to detect early SCR which seems not to affect the long-term survival. We suggest that this could be, probably, linked to early SCR treatment with low dose i.v. steroids.

  2. AES/LEED/I(V) LEED investigation of ultrathin Pb and In layers deposited on Ni(001) and Ni(111) faces

    Energy Technology Data Exchange (ETDEWEB)

    Miskow, Katarzyna; Krupski, Aleksander [Institute of Experimental Physics, University of Wroclaw (Poland)

    2011-07-01

    Properties of ultrathin indium and lead layers deposited on Ni(001) and Ni(111) faces at temperature between T=150 K and T=950 K and coverage up to 6 ML have been studied by AES-t, LEED and I(V) LEED. For In/Ni(111), Frank-van den Merwe and Stranski-Krastanov type of growth is observed for temperature below and above 450 K, respectively. In case of In/Ni(001), below T<600 K it seems that Volumer-Weber or Simultaneous Multilayers type of growth plus Simultaneous Multilayers type of growth. For the adsorption of Pb on Ni(001) only Volumer-Weber type of growth is observed. Two different indium structures have been found for (001) and (111) faces of nickel. For In/Ni(001) the p(2 x 2) structure has been observed for temperature between 600 K and 950 K. At about 950 K, reconstruction of the p(2 x 2) structure to c(2 x 2) one takes place. In case of In/Ni(111) the p(2 x 2) structure has also been observed, but for temperature between 450 K and 850 K. At about 900 K reconstruction of the p(2 x 2) structure to the p(3 x 3)R30 one is observed. In case of Pb/Ni(001) only the c(2 x 2) structure has been observed. Indium makes surface alloy on both nickel crystal faces upon annealing while for lead, only desorption process is observed. The atomic structure and relaxation of the clean Ni(111) surface were investigated with the use of experimental I(V) LEED profiles and theoretical TensErLEED calculations.

  3. I vækkelse

    DEFF Research Database (Denmark)

    Bovbjerg, Kirsten Marie

    2008-01-01

      Margaretha Balle-Petersens artikel 'Guds folk i Danmark' fra 1977 handler om de religiøse vækkelser i 1800-tallets landbosamfund og hvordan de havde forbindelse til lovgivning, nye informationsveje og generel opbrud i de sociale former. Herved sætter Balle Petersen scenen for den etnologiske...... tilgang til studiet af religiøse former som en del af og uløseligt forbundet med hverdagslivet, idet der udviklede sig nye økonomiske dispositioner, nye sociale bånd, nye arbejdsmåder, nye religiøse praksisser, sprog og navneskik i kølvandet på vækkelsen, som var med til at ændre de sociale relationer i...... lokalsamfundene. I sin artikel fører Kirsten Marie Bovbjerg problemstillingen frem til i dag og viser på hvilken måde nye religiøse forestillinger har indflydelse på hverdagslivet og bliver en meningsfuld aktivitet i globaliseret verden med nye typer af informationsveje og spredning af ideer. Bovbjerg har især...

  4. Current-Voltage Relations for Electrochemical Thin Films

    CERN Document Server

    Bazant, M Z; Bayly, B J; Bazant, Martin Z.; Chu, Kevin T.

    2004-01-01

    The dc response of an electrochemical thin film, such as the separator in a micro-battery, is analyzed by solving the Poisson-Nernst-Planck equations, subject to boundary conditions appropriate for an electrolytic/galvanic cell. The model system consists of a binary electrolyte between parallel-plate electrodes, each possessing a compact Stern layer, which mediates Faradaic reactions with nonlinear Butler-Volmer kinetics. Analytical results are obtained by matched asymptotic expansions in the limit of thin double layers and compared with full numerical solutions. The analysis shows that (i) decreasing the system size relative to the Debye screening length decreases the voltage of the cell and allows currents higher than the classical diffusion-limited current; (ii) finite reaction rates lead to the important possibility of a reaction-limited current; (iii) the Stern-layer capacitance is critical for allowing the cell to achieve currents above the reaction-limited current; and (iv) all polarographic (current-v...

  5. Effect of current-voltage characteristics on plasma reforming

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, N. [Univ. of Science and Technology, Daejeon (Korea, Republic of). Environmental System Engineering; Korea Inst. of Machinery and Materials, Daejeon (Korea, Republic of). Environmental System Research Division; Hur, M.; Kim, K.T.; Kim, S.J.; Song, Y.H. [Korea Inst. of Machinery and Materials, Daejeon (Korea, Republic of). Environmental System Research Division

    2010-07-01

    Studies have shown that the energy costs associated with plasma fuel reforming can vary depending on the type of plasma generation technique. The reasons for the different energy costs, however, are not yet clear, since different types of plasma reactor lead to not only different plasma conditions but also lead to different reaction conditions that is not relevant to plasma, such as gas residence time, heat and mass flow conditions. This paper presented the results of a parametric study on methane partial oxidation which was conducted to determine the optimal operating conditions and geometrical design of an arc jet plasma fuel reformer. The arc reactor used in this study was designed to control various operating parameters such as arc length, gas residence time, and gas mixing. Two different types of power supply were tested, notably one that produced high voltage with low current, and one that produced relatively low voltage and high current. The effects of these different voltage-current characteristics on gas reforming process were analyzed based on methane conversion rates, selectivity of products, and thermal efficiencies. The study showed that the input power but not the voltage plays an important role in the present partial oxidation process. The gas residence time was also found to be an important factor in controlling the reformer process. 10 refs., 8 figs.

  6. Current-Voltage Characteristics of Molecular Devices at Low Bias

    Institute of Scientific and Technical Information of China (English)

    LIAO Yun-Xing; CHEN Hao; R.Note; H.Mizuseki; Y.Kawazoe

    2004-01-01

    We use density functional theory and the Green function formalism with charge energy effect included in the self-consistent calculation of the Ⅰ- Ⅴ characteristics of a single benzene ring with an appendage of cf3, and identify some interesting properties of the Ⅰ-Ⅴ characteristics at low bias. The molecule picks up a fractional charge at zero bias, then the additional fractional charge produces a barrier on the junction of the molecule and contacts to perturb current flow on the molecule. This phenomenon may be useful for the design of future molecular devices.

  7. Comparison of platelet clumping and complete blood count results with Sysmex XT-2000iV in feline blood sampled on EDTA or EDTA plus CTAD (citrate, theophylline, adenosine and dipyridamole).

    Science.gov (United States)

    Granat, Fanny; Geffré, Anne; Braun, Jean-Pierre; Trumel, Catherine

    2011-12-01

    False thrombocytopenia may result from platelet aggregation, especially in feline ethylenediamine tetra-acetic acid (EDTA) blood specimens. Citrate, theophylline, adenosine and dipyridamole (CTAD) was added to 46 feline EDTA specimens to test its anti-aggregation action. Platelet aggregation was estimated from blood films and a complete blood count was performed with a Sysmex XT-2000iV analyser. Platelet aggregation score was >2 in 11/46 EDTA tubes and only in one EDTA+CTAD specimen. The platelet count was higher in all CTAD-supplemented tubes except one, medians measured by cytometry being 225.5 × 10(9)/l and 249.0 × 10(9)/l in EDTA and EDTA+CTAD, respectively (P = 0.007). Adding CTAD had statistically and analytically significant but moderate effects on other blood variables, the most intense variations being observed for reticulocytes (about 3% higher in EDTA specimens) and reticulocyte indexes. Addition of CTAD to EDTA when sampling feline blood is a useful option to reduce platelet clumping.

  8. Critical Current Measurements in Commercial Tapes, Coils, and Magnets.

    Science.gov (United States)

    Gubser, D. U.; Soulen, R. J., Jr.; Fuller-Mora, W. W.; Francavilla, T. L.

    1996-03-01

    We have measured a number of tapes, coils, and magnets produced by commercial vendors and determined their properties as functions of magnetic field and temperature. The tapes were measured at the National High Magnetic Field Laboratory in magnetic fields to 20 tesla and at temperatures of 4.2 K, 27 K, 65 K, and 77 K. For the tapes we report critical currents and current-voltage characteristics. Six inch diameter coils were measured at NRL in zero magnetic field. Critical currents, current-voltage characteristics, and reliability studies are reported for the coils. Larger 10 inch diameter coils, which are to be used in a 200 hp superconducting motor, were also measured and results will be presented. The talk will also review the status of the most recent tests of the superconducting motor.

  9. NEW METHOD FOR DETERMINING HEPATITIS B VIRUS RESISTANCE MUTATIONS M204I/V TO NUCLEOS(TIDE ANALOGUES IN PATIENTS WITH CHRONIC HEPATITIS B

    Directory of Open Access Journals (Sweden)

    E. A. Elpaeva

    2015-01-01

    Full Text Available Аnalogues of nucleos(tides (AN such as lamivudine (LAM, telbivudine (TBV, adefovir (ADP, entecavir (ENT are widely used for the treatment of chronic hepatitis B (CHB. However, the prolonged treatment using these drugs often leads to the development of drug resistance. The most common substitutions in the reverse transcriptase are methionine for valine (rtM204V, or methionine for isoleucine (rtM204I at position 204. Early AN-resistant mutations detection is of great importance to determine the treatment strategy of patients with CHB. Currently there are many highly sensitive methods for detection of drug resistance mutations, such as next-generation sequencing, reverse hybridizationbased line probe assay (LiPA, mass spectrometry. However, these methods require expensive equipment and reagents, and they are not widely used in clinical laboratories. The aim of this study was to develop a simple and accurate real-time PCR method for detection of rtM204I/V mutation. This method showed high specificity and sensitivity (1000 copies/ml, it is less laborious and does not require additional equipment, fast and cost effective compared to other methods. HBV mutations of resistance to AN were determined in 5 groups of patients with CHB. Patients of the first group received monotherapy with pegylated interferon (n = 12, the second group — lamivudine (n = 10, the third group — telbivudine (n = 7, the fourth group — entecavir (n = 15. The fifth group consisted of patients who did not receive antiviral therapy (n = 3. The frequency of mutations in HBV polymerase YMDD-motif was determined among 47 patients with CHB: it was 10% for lamivudine treated patients, 20% — for entecavir, 28% — for telbivudine. YIDD/YVDD motifs were identified in two patients and YMDD/YIDD — in one patient. Real-time PCR method for the detection of AN-resistant rtM204I/V mutations in HBV polymerase can be used in routine diagnostics for primary screening of patients not

  10. In vivo kinetics of sup 111 Indium-labelled autologous granulocytes following i. v. administration of granulocyte-macrophage colony-stimulating factor (GM-CSF)

    Energy Technology Data Exchange (ETDEWEB)

    Hovgaard, D.; Mortensen, B.T.; Nissen, N.I. (Department of Hematology, Rigshospitalet, Copenhagen (Denmark)); Schifter, S.; Raboel, A. (Department of Clinical Physiology and Nuclear Medicine, Rigshospitalet, Copenhagen (Denmark))

    1992-01-01

    Administration of both glycosylated and non-glycosylated recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) induces an immediate transient granulocytopenia of 1-3 hours' duration. In order to explore this phenomenon, granulocytes were labelled with {sup 111}Indium and the effect on the kinetics of granulocytes after administration of rhGM-CSF was studied in 10 previously untreated patients with malignant lymphoma. For both types and doses of rhGM-CSF, a significant and dramatic accumulation of the {sup 111}Indium-labelled granulocytes was observed in the lung within a few minutes after i.v. injection of rhGM-CSF. The accumulation of radioactivity coincided with the pronounced and transient granulocytopenia in peripheral blood. The {sup 111}Indium-labelled granulocytes later reappeared in the peripheral blood, indicating reversible pulmonary vascular margination of the granulocytes. Half-life of labelled granulocytes after reappearance was comparable to half-life values under normal conditions. The transient accumulation of granulocytes in the pulmonary vessels seems not to be of clinical importance in the management of patients, but it may to some degree explain previously described side-effects, such as transient hypoxemia (''first-dose'' reaction) following administration of rhGM-CSF. (au).

  11. In vivo kinetics of 111indium-labelled autologous granulocytes following i.v. administration of granulocyte-macrophage colony-stimulating factor (GM-CSF).

    Science.gov (United States)

    Hovgaard, D; Schifter, S; Rabøl, A; Mortensen, B T; Nissen, N I

    1992-04-01

    Administration of both glycosylated and non-glycosylated recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) induces an immediate transient granulocytopenia of 1-3 hours' duration. In order to explore this phenomenon, granulocytes were labelled with 111Indium and the effect on the kinetics of granulocytes after administration of rhGM-CSF was studied in 10 previously untreated patients with malignant lymphoma. For both types and doses of rhGM-CSF, a significant and dramatic accumulation of the 111Indium-labelled granulocytes was observed in the lung within a few minutes after i.v. injection of rhGM-CSF. The accumulation of radioactivity coincided with the pronounced and transient granulocytopenia in peripheral blood. The 111Indium-labelled granulocytes later reappeared in the peripheral blood, indicating reversible pulmonary vascular margination of the granulocytes. Half-life of labelled granulocytes after reappearance was comparable to half-life values under normal conditions. The transient accumulation of granulocytes in the pulmonary vessels seems not to be of clinical importance in the management of patients, but it may to some degree explain previously described side-effects, such as transient hypoxemia ("first-dose" reaction) following administration of rhGM-CSF.

  12. Reducing the V2O3(0001) surface through electron bombardment--a quantitative structure determination with I/V-LEED.

    Science.gov (United States)

    Feiten, Felix E; Kuhlenbeck, Helmut; Freund, Hans-Joachim

    2016-01-28

    The (0001) surface of vanadium sesquioxide, V2O3, is terminated by vanadyl groups under standard ultra high vacuum preparation conditions. Reduction with electrons results in a chemically highly active surface with a well-defined LEED pattern indicating a high degree of order. In this work we report the first quantitative structure determination of a reduced V2O3(0001) surface. We identify two distinct surface phases by STM, one well ordered and one less well ordered. I/V-LEED shows the ordered phase to be terminated by a single vanadium atom per surface unit cell on a quasi-hexagonal oxygen layer with three atoms per two-dimensional unit cell. Furthermore we compare the method of surface reduction via electron bombardment with the deposition of V onto a vanadyl terminated film. The latter procedure was previously proposed to result in a structure with three surface vanadium atoms in the 2D unit cell and we confirm this with simulated STM images.

  13. Development of Automatic Solar Cell I-V Tester and Sorter%全自动太阳能电池测试分选设备的研制

    Institute of Scientific and Technical Information of China (English)

    唐超凡; 魏唯; 宁宗娥; 王学仕; 王娟; 贾京英; 颜秀文

    2011-01-01

    Automatic Solar Cell I-V Tester and Sorter is apecial production equipment,which measures the efficiency and other electrical parameters of the solar cell.Based on the detection and measureing results,the user can define the different types of sorting rules and all data is recorded for quality and history tracking automatically.And the equipment has reached higher levels in design and application of testing part system,sorting part structure,step-motor precise drive,high speed datas exchanging,PCPLC controller mixed and so on.The whole equipment is of high automation,easy operation,high precise test,low wafer breakrupe and high production.The performance can compare with foreign equipments.%太阳能电池测试分选设备是晶体硅太阳能电池生产专用设备,可用于太阳能电池转换效率以及电性能参数测量。所有的测量结果可以自动分类,自动保存。该设备在测试系统设计、分选结构设计、步进电机精密驱动、高速数据交换和电气控制等技术方面达到较高水平。该设备具有全自动化,操作简便,测试精确,运行稳定,碎片率低、生产效率高等特点,性能完全可以和国外同类设备相媲美。

  14. Escalation of i.v. cocaine intake in peri-adolescent vs. adult rats selectively bred for high (HiS) vs. low (LoS) saccharin intake.

    Science.gov (United States)

    Holtz, Nathan A; Carroll, Marilyn E

    2013-05-01

    Adolescence marks a period of increased vulnerability to the development of substance use disorders. High sweet preference is a genetically mediated behavioral trait that also predicts vulnerability to substances of abuse. Previous research has shown that while adolescent rats selectively bred for high (HiS) saccharin intake acquire cocaine self-administration at the same rate as adult HiS rats, adolescent rats bred for low saccharin intake (LoS) acquire cocaine self-administration faster than adult LoS rats. This study was conducted to investigate the interaction of the addiction vulnerability factors of peri-adolescence and saccharin preference on cocaine intake using an animal model of escalation of cocaine consumption over 6-h/day sessions. Peri-adolescent and adult HiS and LoS female rats self-administered i.v. cocaine (0.4 mg/kg/inf) during short-access (2-h/day) sessions for 2 days. Next, a long-access (6-h/day) period (LgA) commenced and lasted 16 days. Following LgA, session length was returned to 2-h/day for a second short access phase. LoS peri-adolescent rats escalated cocaine intake over the LgA period and consumed more drug than LoS adult rats; however, peri-adolescent and adult HiS rats consumed similar amounts of cocaine during this period. Additionally, adult HiS rats self-administered more cocaine than adult LoS rats during the LgA period, while there was no phenotypic difference between the rat lines during peri-adolescence for the LgA period. During the first short-access phase, peri-adolescent rats self-administered more cocaine than adult rats. These results emphasize the importance of adolescent drug abuse prevention by illustrating that phenotypic protection from addiction may not be expressed until adulthood.

  15. The assessment of character´s virtues and strengths in Argentine children: Adaptation and validation of the Inventory of Virtues and Strengths for Children (I.V&S. Children

    Directory of Open Access Journals (Sweden)

    Aldana Sol Grinhauz

    2014-03-01

    Full Text Available This study aimed the adaptation and validation of the Inventory of Virtues and Strengths (I.V.&S., Cosentino & Castro Solano, 2008 in children aged 10-12 years. The I.V.&S. Children is a useful tool for assessing human virtues and strengths according to Peterson and Seligman´s (2004 six virtues and 24 strengths classification of character. 518 children (254 males and 263 females between 10 and 12 years and attending to public and private schools of the City of Buenos Aires (Argentina were part of this study. Regarding the I.V.&S. Children factor´s structure, the exploratory factor analysis allowed the extraction of six factors that accounted for 46.15 % of the variance. Confirmatory factor analysis showed an adequate fit to the model. As to convergent validity evidence, statistically significant and positive correlations were found between scores by I.V&S. Children and Children’s Social Desirability Scale (EDESI, Lemos, 2005, the Argentine Children’s Personality Questionnaire (ICSC, Lemos, 2006 and the question about life satisfaction: “How satisfied or happy are you with your life?”.

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

    Energy Technology Data Exchange (ETDEWEB)

    Vanderberg, B.H.; Eninger, J.E. [Department of Industrial Electrotechnology, Royal Institute of Technology, S-100 44 Stockholm (Sweden)

    1997-02-01

    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} {ital 1997 American Institute of Physics.}

  17. 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.    

  18. 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

  19. Local I-V characteristics of high-k ultra-thin ZrO{sub 2}- and ZrO{sub 2}/Al{sub 2}O{sub 3}/ZrO{sub 2}-films.

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Dominik; Grube, Matthias; Erben, Elke; Schroeder, Uwe; Weber, Walter [namlab Gmbh, D-01187 Dresden (Germany); Mueller, Johannes; Weinreich, Wenke [Fraunhofer-CNT, D-01099 Dresden (Germany); Geelhaar, Lutz; Riechert, Henning [Paul-Drude-Institut fuer Festkoerperelektronik, D-10117 Berlin (Germany); Mikolajick, Thomas [namlab Gmbh, D-01187 Dresden (Germany); Chair of Nanoelectronic Materials, 01062 Dresden (Germany)

    2011-07-01

    In order to produce ultra thin ZrO{sub 2}-films, with a dielectric constant high enough to satisfy industry demands, it is necessary to reach the tetragonal crystalline phase. This can be achieved either by high temperature deposition or by a post deposition annealing step. Both however induce high leakage currents. Small amounts of Al{sub 2}O{sub 3} can be incorporated in ZrO{sub 2} to reduce leakage current. To get more insight into the charge carrier transport mechanisms involved, a thickness series of ultra thin ZrO{sub 2}- and ZrO{sub 2}/Al{sub 2}O{sub 3}/ZrO{sub 2}-films were deposited by ALD and subjected to different rapid thermal annealing processes. These layers were examined by GI-XRD, TEM, I-V-, C-V-Spectroscopy and conductive atomic force microscopy. Thus, leakage currents are reduced to 3.2.10{sup -8}(A)/(cm{sup 2}) at 1 V while maintaining the high k value (CET=1 nm at 1 V for a 10 nm film). CAFM studies demonstrate how the crystallization effects the charge transport mechanisms on the mesoscopic scale. Local I-V curves acquired on amorphous films and at grain boundaries in nanocrystalline films in yield lower breakdown voltages and higher leakage currents at crystallite grain boundaries.

  20. LEED I/V determination of the structure of a MoO3 monolayer on Au(111): Testing the performance of the CMA-ES evolutionary strategy algorithm, differential evolution, a genetic algorithm and tensor LEED based structural optimization

    Science.gov (United States)

    Primorac, E.; Kuhlenbeck, H.; Freund, H.-J.

    2016-07-01

    The structure of a thin MoO3 layer on Au(111) with a c(4 × 2) superstructure was studied with LEED I/V analysis. As proposed previously (Quek et al., Surf. Sci. 577 (2005) L71), the atomic structure of the layer is similar to that of a MoO3 single layer as found in regular α-MoO3. The layer on Au(111) has a glide plane parallel to the short unit vector of the c(4 × 2) unit cell and the molybdenum atoms are bridge-bonded to two surface gold atoms with the structure of the gold surface being slightly distorted. The structural refinement of the structure was performed with the CMA-ES evolutionary strategy algorithm which could reach a Pendry R-factor of ∼ 0.044. In the second part the performance of CMA-ES is compared with that of the differential evolution method, a genetic algorithm and the Powell optimization algorithm employing I/V curves calculated with tensor LEED.

  1. Effects of precursor solution composition on the performance and I-V hysteresis of perovskite solar cells based on CH3NH3PbI3-xClx

    Science.gov (United States)

    Zhang, Z. L.; Men, B. Q.; Liu, Y. F.; Gao, H. P.; Mao, Y. L.

    2017-02-01

    Precursor solution of CH3NH3PbI3-xClx for perovskite solar cells was conventionally prepared by mixing PbCl2 and CH3NH3I with a mole ratio of 1:3 (PbCl2:CH3NH3I). While in the present study, CH3NH3PbI3-xClx-based solar cells were fabricated using the precursor solutions containing PbCl2 and CH3NH3I with the mole ratios of 1:3, 1.05:3, 1.1:3, and 1.15:3, respectively. The results display that the solar cells with the mole ratio of 1.1:3 present higher power conversion efficiency and less I-V hysteresis than those with the mole ratio of 1:3. Based on some investigations, it is concluded that the higher efficiency could be due to the smooth and pinhole free film formation, high optical absorption, suitable energy band gap, and the large electron transfer efficiency, and the less I-V hysteresis may be attributed to the small low frequency capacitance of the device.

  2. Development of Tunneling Spectroscopy Apparatus for Kelvin and Sub-Kelvin Measurements of Superconducting Energy Gaps by Multi-disciplinary students at a Liberal Arts University

    Science.gov (United States)

    Eckhardt, Matt

    2014-03-01

    Tunneling spectroscopy is an important technique used to measure the superconducting energy gap, a feature that is at the heart of the nature of superconductivity in various materials. In this presentation, we report the progress and results in developing high-resolution tunneling spectroscopy experimental platforms in a helium three cryostat, a 3 Kelvin cryocooler and a helium dip-tester. The experimental team working in a liberal arts university is a multi-disciplinary group consisting of one physics major, chemisty majors and a biology major. Students including non-physics majors learned and implemented current-voltage measurement techniques, vacuum system engineering, built electronic boxes and amplifier circuits from scratch, built custom multi-conductor cables for thermometry and current-voltage measurements, and performed conductance measurements. We report preliminary results. Acknowledgments: We acknowledge support from National Science Foundation Grant # DMR-1206561.

  3. Traveling-wave solutions of a modified Hodgkin-Huxley type neural model via Novel analytical results for nonlinear transmission lines with arbitrary I(V characteristics

    Directory of Open Access Journals (Sweden)

    Valentino Anthony Simpao

    2000-01-01

    Full Text Available Herein an enhanced Hodgkin-Huxley (H-H type model of neuron dynamics is solved analytically via formal methods. Our model is a variant of an earlier one by M.A. Mahrous and H.Y. Alkahby [1]. Their modified model is realized by a hyperbolic quasi-linear diffusion operator with time-delay parameters; this compared to the original H-H model with standard parabolic quasi-linear diffusion operator and no time-delay parameters. Besides these features, the present model also incorporates terms describing signal dissipation into the background substrate (e.g., conductance to ground, making it more experimentally amenable. The solutions which results via the present scheme are of traveling-wave profile, which agree qualitatively with those observed in actual electro-physiological measurements made on the neural systems originally studied by H-H These results confirm the physiological soundness of the enhanced model and of the preliminary assumptions which motivated the present solution strategy; the comparison of the present results with actual electro-physiological data displays shall appear in later publications.

  4. 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.

  5. 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

  6. 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

  7. Mat markaðarins á virði vörumerkisins Vodafone. Hver er ímynd Vodafone meðal háskólanema á Íslandi?

    OpenAIRE

    Gunnar Örn Runólfsson 1988

    2013-01-01

    Fjarskiptafyrirtækið Fjarskipti hf. eða Vodafone eins og það er nefnt í daglegu tali starfar í miklu samkeppnisumhverfi. Aukin notkun einstaklinga og fyrirtækja á fjarskiptaþjónustu hefur leitt til þess að sífellt meiri kröfur eru gerðar til þjónustu fjarskiptafyrirtækja. Virði vörumerkis hefur talsverð á áhrif á núverandi og verðandi viðskiptavini og þar af er ímynd lykilþáttur í uppbyggingu vörumerkjavirðis. Fyrirtæki sem leitast eftir að auka ánægju viðskiptavina, þurfa að þekkja þarfir þ...

  8. 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.  

  9. I-V characteristics of foilless diodes

    Institute of Scientific and Technical Information of China (English)

    Liu Guo-Zhi; Huang Wen-Hua; Yang Zhan-Feng

    2005-01-01

    Some physical characteristics of foilless diodes are obtained and analysed by numerical simulations. Relations between diode current andconfiguration parameters, i.e. diode voltage and external magnetic field, are investigated.Employing these relations and assuming that the external magnetic field is strong enough, the diode current can be approximately written as Ib=(7.5/x)(x+(0.81-x)/(1+0.7Ld2/δr))(γ0 2/3-1)3/2, in which Ld is the Anode-Cathode(AK) gap, Rc the outer radius of cathode, and Rp the radius of drifting tube; x=ln(Rp/Rc), δr=Rp- Rc. This expression is comparatively accurate for different configuration parameters and voltages; results obtained from this expression are consistent with that of numerical simulations within an error of 10%.

  10. 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.

  11. Effects of SILAR cycle on the electrical characteristics of Cd/CdSe/n-Si/Au-Sb structure

    OpenAIRE

    2011-01-01

    Cd/CdSe/n-Si/Au-Sb structures have been fabricated by Successive Ionic Layer Adsorption and Reaction (SILAR) method under various SILAR cycles. The characteristics parameters of these structures such as barrier height, ideality factor, series resistance are calculated from the current-voltage (I-V) measurements and the barrier height, carrier concentration are calculated from reverse bias capacitance-voltage (C-V) measurements at 300 kHz frequency and room temperature. Furthermore, t...

  12. Electro-Plating and Characterisation of CdTe Thin Films Using CdCl2 as the Cadmium Source

    OpenAIRE

    Nor A. Abdul-Manaf; Hussein I. Salim; Mohammad L. Madugu; Olajide I. Olusola; Imyhamy M. Dharmadasa

    2015-01-01

    Cadmium telluride (CdTe) thin films have been successfully prepared from an aqueous electrolyte bath containing cadmium chloride (CdCl2)·H2O and tellurium dioxide (TeO2) using an electrodeposition technique. The structural, electrical, morphological and optical properties of these thin films have been characterised using X-ray diffraction (XRD), Raman spectroscopy, optical profilometry, DC current-voltage (I-V) measurements, photoelectrochemical (PEC) cell measurement, scanning electron micr...

  13. Measurement of ion and electron temperatures in plasma blobs by using an improved ion sensitive probe system and statistical analysis methods.

    Science.gov (United States)

    Okazaki, K; Tanaka, H; Ohno, N; Ezumi, N; Tsuji, Y; Kajita, S

    2012-02-01

    We have measured ion temperature as well as electron temperature in plasma blobs observed in a linear plasma device by using an improved ion sensitive probe. Current-voltage characteristics of the ion sensitive probe inside and outside plasma blobs were re-constructed with a conditional sampling method. It is clearly found that both ion and electron temperatures in plasma blobs decrease more slowly in a cross-field direction than those in a bulk plasma without plasma blobs.

  14. Measurement of ion and electron temperatures in plasma blobs by using an improved ion sensitive probe system and statistical analysis methods

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, K.; Tanaka, H.; Ohno, N.; Tsuji, Y. [Graduate School of Engineering, Nagoya University, Nagoya, Aichi 464-8603 (Japan); Ezumi, N. [Nagano National College of Technology, Nagano 381-8550 (Japan); Kajita, S. [EcoTopia Science Institute, Nagoya University, Nagoya, Aichi 464-8603 (Japan)

    2012-02-15

    We have measured ion temperature as well as electron temperature in plasma blobs observed in a linear plasma device by using an improved ion sensitive probe. Current-voltage characteristics of the ion sensitive probe inside and outside plasma blobs were re-constructed with a conditional sampling method. It is clearly found that both ion and electron temperatures in plasma blobs decrease more slowly in a cross-field direction than those in a bulk plasma without plasma blobs.

  15. Measuring thermoelectric property of nano-heterostructure

    Institute of Scientific and Technical Information of China (English)

    Lu Hong-Liang; Zhang Chen-Dong; Cai Jin-Ming; Gao Min; Zou Qiang; Guo Hai-Ming; Gao Hong-Jun

    2011-01-01

    A method of measuring the thermoelectric power of nano-heterostructures based on four-probe scanning tunneling microscopy is presented.The process is composed of the in-situ fabrication of a tungsten-indium tip,the precise control of the tip-sample contact and the identification of thermoelectric potential.When the temperature of the substrate is elevated,while that of the tip is kept at room temperature,a thermoelectric potential occurs and can be detected by a current-voltage measurement.As an example of its application,the method is demonstrated to be effective to measure the thermoelectric power in several systems.A Seebeck coefficient of tens of μV/K is obtained in graphene epitaxially grown on Ru (0001) substrate and the thermoelectric potential polarity of this system is found to be the reverse of that of bare Ru (0001) substrate.

  16. CORRELATING I-V CURVE OF SOLAR CELLS WITH COMBINATION ALGORITHM OF IRAGA AND ACA%用IRAGA与ACA融合算法拟合太阳电池I-V曲线

    Institute of Scientific and Technical Information of China (English)

    王志明; 唐冬梅; 魏光普

    2013-01-01

    In order to obtain more accurate parameters of solar cells,a fusion algorithm was proposed based on improved accelerating genetic algorithm (IRAGA) and ant colony algorithm (ACA) after analyzing the disadvantages of double exponential algorithms,Taylor comparison algorithm and Quasi-Monte Carlo algorithm in correlating I-V curve of solar cell and combining with the advantages of IRAGA and ACA.First,the objective function was established to determine the scope of optimization parameters based on the solar cell model equation.Then the rules of the fusion algorithm based on IRAGA and ACA was made to determine the degree of initial information and other related parameters.Finally,the match was made with Matlab.The results showed that the integration of IRAGA and ACA algorithm not only greatly improves the computational efficiency of original algorithm,speeds up the convergence rate and avoids the probability of obtaining local solutions,but also the maximum relative deviation of correlated I-V curve of solar cell can be controlled within 0.1% and the optimal characteristic parameters values can be obtained.%为了较精确获取太阳电池的特性参数,分析比较双指数算法、泰勒比较算法、伪蒙特卡罗等算法拟合太阳电池I-V曲线的不足之处,结合改进加速遗传算法(IRAGA)与蚁群算法(ACA)的优点,提出基于IRAGA与ACA融合算法.首先,以太阳电池模型方程为基础,建立目标函数,确定特性参数的寻优范围;然后制定IRAGA与ACA融合算法的规则,确定信息度初值等相关参数,最后用Matlab进行拟合分析.结果表明:IRAGA与ACA算法的融合,不仅大大提高了原来算法的计算效率,而且加快了算法的收敛速度,避免了产生局部解的概率.而且可准确拟合太阳电池I-V曲线,使得拟合的最大相对偏差可控制在0.1%之内.同时,还可获得特性参数的最佳参数值.

  17. 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

  18. Robust Measurement of Thin-Film Photovoltaic Modules Exhibiting Light-Induced Transients: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Deceglie, Michael, G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-09-09

    Light-induced changes to the current-voltage characteristic of thin-film photovoltaic modules (i.e. light-soaking effects) frustrate the repeatable measurement of their operating power. We describe best practices for mitigating, or stabilizing, light-soaking effects for both CdTe and CIGS modules to enable robust, repeatable, and relevant power measurements. We motivate the practices by detailing how modules react to changes in different stabilization methods. We also describe and demonstrate a method for validating alternative stabilization procedures, such as those relying on forward bias in the dark. Reliable measurements of module power are critical for qualification testing, reliability testing, and power rating.

  19. Robust measurement of thin-film photovoltaic modules exhibiting light-induced transients

    Science.gov (United States)

    Deceglie, Michael G.; Silverman, Timothy J.; Marion, Bill; Kurtz, Sarah R.

    2015-09-01

    Light-induced changes to the current-voltage characteristic of thin-film photovoltaic modules (i.e. light-soaking effects) frustrate the repeatable measurement of their operating power. We describe best practices for mitigating, or stabilizing, light-soaking effects for both CdTe and CIGS modules to enable robust, repeatable, and relevant power measurements. We motivate the practices by detailing how modules react to changes in different stabilization methods. We also describe and demonstrate a method for validating alternative stabilization procedures, such as those relying on forward bias in the dark. Reliable measurements of module power are critical for qualification testing, reliability testing, and power rating.

  20. Influence of Illumination on the Electrical Properties of p-(ZnMgTe/ZnTe:N)/CdTe/n-(CdTe:I)/GaAs Heterojunction Grown by Molecular Beam Epitaxy (MBE)

    Science.gov (United States)

    Jum'h, I.; Abd El-Sadek, M. S.; Al-Taani, H.; Yahia, I. S.; Karczewski, G.

    2016-11-01

    Heterostructure p-(ZnMgTe/ZnTe:N)/CdTe/n-(CdTe:I)/GaAs was evaporated using molecular beam epitaxy and investigated for photovoltaic energy conversion application. The electrical properties of the studied heterostructure were measured and characterized in order to understand the relevant electrical transport mechanisms. Electrical properties derived from the current-voltage (I-V) characteristics of solar cells provide essential information necessary for the analysis of performance losses and device efficiency. I-V characteristics are investigated in dark conditions and under different light intensities. All the electrical and power parameters of the heterostructure were measured, calculated and explained.

  1. Influence of Illumination on the Electrical Properties of p-(ZnMgTe/ZnTe:N)/CdTe/n-(CdTe:I)/GaAs Heterojunction Grown by Molecular Beam Epitaxy (MBE)

    Science.gov (United States)

    Jum'h, I.; Abd El-Sadek, M. S.; Al-Taani, H.; Yahia, I. S.; Karczewski, G.

    2017-02-01

    Heterostructure p-(ZnMgTe/ZnTe:N)/CdTe/n-(CdTe:I)/GaAs was evaporated using molecular beam epitaxy and investigated for photovoltaic energy conversion application. The electrical properties of the studied heterostructure were measured and characterized in order to understand the relevant electrical transport mechanisms. Electrical properties derived from the current-voltage ( I- V) characteristics of solar cells provide essential information necessary for the analysis of performance losses and device efficiency. I- V characteristics are investigated in dark conditions and under different light intensities. All the electrical and power parameters of the heterostructure were measured, calculated and explained.

  2. Sledování fázových transformací při výpalu stavebních pojiv pomocí HT-XRD analýzy

    OpenAIRE

    Soukupová, Veronika

    2016-01-01

    Předkládaná bakalářská práce se zabývá sledováním fázových transformací při výpalu stavebních pojiv pomocí HT – XRD difrakční analýzy. V rámci práce bylo provedeno měření a vyhodnocení a následné ověření výsledků s teoretickými podklady. Byla zhodnocena vhodnost použití vysokoteplotní difrakční analýzy pro sledování fázových transformací stavebních pojiv. Presented bachelor thesis deals with the study of phase transformations during burning of construction binders using HT - XRD diffractio...

  3. 钙钛矿太阳能电池:器件设计和I-V滞回现象%Perovskite Solar Cells: Device Construction and I-V Hysteresis

    Institute of Scientific and Technical Information of China (English)

    张烨; 姚志博; 林仕伟; 李建保; 林红

    2015-01-01

    基于染料敏化太阳能电池发展起来的有机-无机杂化钙钛矿太阳能电池经过不到5年的快速发展,光电转换效率从最初的3.8%提高到了经过认证的17.9%.但是常用结构的钙钛矿太阳能电池在性能测试过程中的电流-电压(I-V)曲线会随着测试器件扫描方向的不同而明显不同.该现象被称为I-V滞回现象.进一步研究发现I-V曲线还与扫描速度、起始测试的偏压值和光照历史明显相关.本工作结合不同的器件构造,就可能造成这种I-V滞回现象的不同原因进行了总结和分析,并对如何获得可靠的光电转换效率的测试方法进行了评述.

  4. Interface Superconductivity in Graphite- and CuCl-Based Heterostructures

    Science.gov (United States)

    2015-01-22

    increases, I-V characteristics demonstrate more complex behavior related to the switching between metallic and insulating states (Figs. 6-7). The...performed magnetization M(H,T) and electron spin resonance (ESR) measurements in both insulating and metallic states with no difference between the...linear current-voltage characteristics, intermittent switching between low- and high-resistance states, aging effect, and negative parabolic magneto

  5. 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 .

  6. Contact characterizations of ZrN thin films obtained by reactive sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Pelleg, J. [Department of Materials Engineering, Ben Gurion University of the Negev, 84105 Beer Sheva (Israel)]. E-mail: pelleg@bgumail.bgu.ac.il; Bibi, A. [Department of Materials Engineering, Ben Gurion University of the Negev, 84105 Beer Sheva (Israel); Sinder, M. [Department of Materials Engineering, Ben Gurion University of the Negev, 84105 Beer Sheva (Israel)

    2007-04-30

    The contact properties of ZrN {sub x} on p-type Si obtained by magnetron reactive sputtering were investigated. Schottky diode characteristics were observed as determined by forward current-voltage (I-V) and capacitance-voltage (C-V) measurements. The zero-bias barrier heights evaluated by I-V were in the range of 0.55-0.63 V, which is higher than the value of 0.53 V of as-deposited amorphous TiN.

  7. Intrinsic Josephson effects in submicrometre Bi2212 mesas fabricated by using focused ion beam etching

    Energy Technology Data Exchange (ETDEWEB)

    Winkler, D.; Mros, N.; Tarte, E.J.; Yurgens, A.; Krasnov, V.M. [Department of Microelectronics and Nanoscience, Chalmers University of Technology and Goeteborg University, SE-412 96 Goeteborg (Sweden); Foord, D.T.; Booij, W.E.; Blamire, M.G. [IRC in Superconductivity, University of Cambridge, Madingley Road, Cambridge CB3 0HE (United Kingdom)

    1999-11-01

    We have investigated the current-voltage (I-V) characteristics of sub-{mu}m sized mesas made on the surface of Bi{sub 2}Sr{sub 2}CaCu{sub 2}O{sub 8} (Bi2212) single crystals. The mesas were fabricated using focused ion beam etching. The samples showed excellent I-V characteristics and their conductance-voltage (G-V) curves were measured from above the transition temperature down to 4.2 K. New ways of making annular mesas with diameters down to 0.5 {mu}m were also investigated. (author)

  8. Electrical and infrared properties of thin niobium microbolometers near T(sub c)

    Science.gov (United States)

    Grossman, E. N.; Sauvageau, J. E.; Mcdonald, D. G.

    1992-01-01

    Niobium microbolometers approximately 1 micron wide x 2 micron long x 10 nm thick have been integrated at the feeds of equiangular spiral antennas made of 200 nm thick Nb. The device's current-voltage characteristics and infrared responsivity as a function of DC bias voltage were measured over a range of temperature spanning approximately plus or minus 2 percent around T(sub c). The greatest voltage responsivity occurs well below T(sub c), in a regime where the I-V curve is significantly hysteretic due to self-heating and resembles the I-V curve of a superconducting microbridge.

  9. Charge transport and memristive properties of graphene quantum dots embedded in poly(3-hexylthiophene) matrix

    Energy Technology Data Exchange (ETDEWEB)

    Cosmin Obreja, Alexandru; Cristea, Dana; Radoi, Antonio; Gavrila, Raluca; Comanescu, Florin; Kusko, Cristian, E-mail: cristian.kusko@imt.ro [National Institute for R and D in Microtechnologies, 72996, Bucharest (Romania); Mihalache, Iuliana [National Institute for R and D in Microtechnologies, 72996, Bucharest (Romania); Physics Department, University Bucharest, P.O. Box MG-11, 077125 Bucharest (Romania)

    2014-08-25

    We show that graphene quantum dots (GQD) embedded in a semiconducting poly(3-hexylthiophene) polymeric matrix act as charge trapping nanomaterials. In plane current-voltage (I-V) measurements of thin films realized from this nanocomposite deposited on gold interdigitated electrodes revealed that the GQD enhanced dramatically the hole transport. I-V characteristics exhibited a strong nonlinear behavior and a pinched hysteresis loop, a signature of a memristive response. The transport properties of this nanocomposite were explained in terms of a trap controlled space charge limited current mechanism.

  10. Conductive Atomic Force Microscopy (C-AFM) observation of conducting nanofilaments formation in GeSbTe phase change materials

    Science.gov (United States)

    Yang, Fei; Xu, Ling; Fang, Li; Jiang, Yifan; Xu, Jun; Su, Weining; Yu, Yao; Ma, Zhongyuan; Chen, Kunji

    2013-09-01

    GST (GeSbTe) thin films were deposited on glass substrates by electron beam evaporation; Ni was used as the top and bottom electrodes. The I- V (current-voltage) characteristic of the phase change memory (PCM) cell was measured; results showed an electrical threshold switching characteristic for the sample with a threshold voltage of 3.08 V. The threshold switching is attributed to the formation of conductive filaments in the amorphous matrix. Current-voltage spectra which were obtained by C-AFM show that the GST thin film switching from amorphous to the crystalline phase occurs at 1.51 V. C-AFM was used to fabricate crystalline nanoarrays on the sample surface and examine the electrical properties of arrays. In the I- V measurements by C-AFM, when the applied voltage is higher than threshold voltage, conducting nanofilaments with average sizes of 15-60 nm were formed and crystallized spots with current signals were observed. Different times of I- V spectroscopies were applied on thin films to investigate the electrical properties of films during the phase change process. C-AFM results show that as the times of I- V spectroscopies increased, the morphology of crystallized spots changed from bump to pit; the sizes of conductive nanofilaments and detected current signals increased. These results can be attributed to the energy induced by Joule heating dissipated to surrounding films increases with the increasing times of I- V spectroscopies.

  11. 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

    2016-07-01

    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.

  12. 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.

  13. Measurement of thermophysical properties by a pulse-heating technique

    Institute of Scientific and Technical Information of China (English)

    Peng Xiao; Jingmin Dai; Qingwei Wang

    2007-01-01

    A technique is described for the dynamic measurement of selected thermophysical properties of electrically conducting solids in the temperature range from 1100 K to the melting point. Based on rapid resistive self-heating of the specimen from room temperature to any desired high temperature in several seconds by the passage of an electical current pulse through it, this technique measures the pertinent quantities such as current, voltage, randiance temperature, with sub-millisecond time resolution. The pulse-heating technique is applied to strip specimens. The radiance temperature is measured by high-speed pyrometry,normal spectral emissivity of the strips is measured by integrating sphere reflectometry. The normal spectral emissivity results are used to compute the true temperature of the specimens. The heat capacity,electrical resistivity, total hemispherical emissivity are evaluated in the temperature range from 1100 K to the melting point.

  14. Simultaneous Measurements of Electrostatic and Magnetic Fluctuations in ASDEX Upgrade Edge Plasma

    DEFF Research Database (Denmark)

    Ionita, Codrina; Vianello, Nicola; Müller, H.W.

    2009-01-01

    in such a way that simultaneously the poloidal and radial electric field components, the ion saturation current and the current-voltage characteristic can be registered. During the AUG discharges of 7 s lengths the probe head is inserted two to three times for 100 ms each by the midplane manipulator......In ASDEX Upgrade (AUG) electrostatic and magnetic fluctuations in the edge plasma region were measured simultaneously during ELMy H-mode (high confinement) plasmas and L-mode (low confinement) plasmas and during a transition between the two modes. A special probe was used containing six Langmuir...

  15. Calculation Model for Current-voltage Relation of Silicon Quantum-dots-based Nano-memory

    Institute of Scientific and Technical Information of China (English)

    YANG Hong-guan; DAI Da-kang; YU Biao; SHANG Lin-lin; GUO You-hong

    2007-01-01

    Based on the capacitive coupling formalism, an analytic model for calculating the drain currents of the quantum-dots floating-gate memory cell is proposed. Using this model, one can calculate numerically the drain currents of linear, saturation and subthreshold regions of the device with/without charges stored on the floating dots. The read operation process of an n-channel Si quantum-dots floating-gate nano-memory cell is discussed after calculating the drain currents versus the drain to source voltages and control gate voltages in both high and low threshold states respectively.

  16. Concentration polarization with monopolar ion exchange membranes: current-voltage curves and water dissociation

    NARCIS (Netherlands)

    Krol, J.J.; Wessling, M.; Strathmann, H.

    1999-01-01

    Concentration polarization is studied using a commercial anion and cation exchange membrane. Current¿voltage curves show the occurrence of an overlimiting current. The nature of this overlimiting current is investigated in more detail, especially with respect to the contribution of water dissociatio

  17. 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.

  18. 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.

  19. Antiferromagentic resonance detected by direct current voltages in MnF{sub 2}/Pt bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Ross, Philipp, E-mail: philipp.ross.13@ucl.ac.uk [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Schreier, Michael, E-mail: michael.schreier@wmi.badw.de; Lotze, Johannes [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, Technische Universität München, Garching (Germany); Huebl, Hans; Goennenwein, Sebastian T. B. [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Nanosystems Initiative Munich, Munich (Germany); Gross, Rudolf [Walther-Meißner-Institut, Bayerische Akademie der Wissenschaften, Garching (Germany); Physik-Department, Technische Universität München, Garching (Germany); Nanosystems Initiative Munich, Munich (Germany)

    2015-12-21

    We performed coplanar waveguide-based broadband ferromagnetic resonance experiments on the antiferromagnetic insulator MnF{sub 2}, while simultaneously recording the DC voltage arising in a thin platinum film deposited onto the MnF{sub 2}. The antiferromagnetic resonance is clearly reflected in both the transmission through the waveguide as well as the DC voltage in the Pt strip. The DC voltage remains largely unaffected by field reversal and thus presumably stems from microwave rectification and/or heating effects. However, we identify a small magnetic field orientation dependent contribution, compatible with antiferromagnetic spin pumping theory.

  20. Current-voltage behaviour of bipolar membranes in concentrated salt solutions investigated with chronopotentiometry

    NARCIS (Netherlands)

    Wilhelm, F.G.; Vegt, van der N.F.A.; Strathmann, H.; Wessling, M.

    2002-01-01

    Chronopotentiometry is used as a tool to obtain detailed information on the transport behaviour of the bipolar membrane BP-1 in solutions of high sodium chloride concentration above the limiting current density. We discuss critically the interpretation of the observed transition times. The occurrenc

  1. 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....

  2. Measurement of Habitual Physical Activity Performance in Adolescents with Cerebral Palsy: A Systematic Review

    Science.gov (United States)

    Clanchy, Kelly M.; Tweedy, Sean M.; Boyd, Roslyn

    2011-01-01

    Aim: This systematic review compares the validity, reliability, and clinical use of habitual physical activity (HPA) performance measures in adolescents with cerebral palsy (CP). Method: Measures of HPA across Gross Motor Function Classification System (GMFCS) levels I-V for adolescents (10-18y) with CP were included if at least 60% of items…

  3. Measurement of Local Peltier Constant at a Microcontact

    Science.gov (United States)

    Koyano, Mikio; Akashi, Naoya

    2009-07-01

    Our novel apparatus measures the local Peltier constant at a thermoelectric material microregion. A narrow metal needle probe contacts a sample mounted into a small adiabatic vacuum chamber with a pressure of about 10-4 Pa. A␣stepping-motor-type nano-actuator controls the probe’s contact pressure. We measured DC and AC I- V characteristics at the microcontact to determine thermoelectric properties. We measured I- V characteristics between the probe and a commercial (Bi,Sb)2Te3 surface. Measured values of local Peltier constants are of the same order as the bulk Peltier constant π: ca. 55 mV. They increase with increased contact resistance, suggesting that contact size affects thermoelectricity.

  4. Validation of measurements of ventilation-to-perfusion ratio inequality in the lung from expired gas

    Science.gov (United States)

    Prisk, G. Kim; Guy, Harold J B.; West, John B.; Reed, James W.

    2003-01-01

    The analysis of the gas in a single expirate has long been used to estimate the degree of ventilation-perfusion (Va/Q) inequality in the lung. To further validate this estimate, we examined three measures of Va/Q inhomogeneity calculated from a single full exhalation in nine anesthetized mongrel dogs under control conditions and after exposure to aerosolized methacholine. These measurements were then compared with arterial blood gases and with measurements of Va/Q inhomogeneity obtained using the multiple inert gas elimination technique. The slope of the instantaneous respiratory exchange ratio (R slope) vs. expired volume was poorly correlated with independent measures, probably because of the curvilinear nature of the relationship due to continuing gas exchange. When R was converted to the intrabreath Va/Q (iV/Q), the best index was the slope of iV/Q vs. volume over phase III (iV/Q slope). This was strongly correlated with independent measures, especially those relating to inhomogeneity of perfusion. The correlations for iV/Q slope and R slope considerably improved when only the first half of phase III was considered. We conclude that a useful noninvasive measurement of Va/Q inhomogeneity can be derived from the intrabreath respiratory exchange ratio.

  5. 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.

  6. Measurement and understanding of single-molecule break junction rectification caused by asymmetric contacts.

    Science.gov (United States)

    Wang, Kun; Zhou, Jianfeng; Hamill, Joseph M; Xu, Bingqian

    2014-08-01

    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.

  7. 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...

  8. Against coefficient of variation for estimation of intraindividual variability with accuracy measures

    Directory of Open Access Journals (Sweden)

    Philippe Golay

    2013-02-01

    Full Text Available Previous studies have shown that intraindividual variability (iV in performance is an important indicator of individual’s cognitive functioning and neurological integrity. While most experiments have examined iV of performance using Reaction Time data (RTs, few studies have considered it with accuracy measures (e.g. number or percentage of correct responses. For these two types of measures, intraindividual standard deviation (iSD or intraindividual coefficient of variation (iCV; intraindividual standard deviation divided by the individual mean were used as indicators of iV in performance. However, because accuracy data have a lower and an upper bound (in contrast to RTs, we illustrate both formally and with simulated data, that the iCV cannot be used with accuracy measures. We also show that the coefficient iCV is influenced by the number of items which is an issue when dealing with missing data. We further provide formulas that may help researchers to visualize and correctly interpret their data using any spreadsheet software. The current article finally proposes an alternative coefficient (zeta to examine iV in performance with accuracy measures that shows similar behaviour as does iCV with RTs data.

  9. MIS capacitor studies on silicon carbide single crystals

    Science.gov (United States)

    Kopanski, J. J.

    1990-01-01

    Cubic SIC metal-insulator-semiconductor (MIS) capacitors with thermally grown or chemical-vapor-deposited (CVD) insulators were characterized by capacitance-voltage (C-V), conductance-voltage (G-V), and current-voltage (I-V) measurements. The purpose of these measurements was to determine the four charge densities commonly present in an MIS capacitor (oxide fixed charge, N(f); interface trap level density, D(it); oxide trapped charge, N(ot); and mobile ionic charge, N(m)) and to determine the stability of the device properties with electric-field stress and temperature. The section headings in the report include the following: Capacitance-voltage and conductance-voltage measurements; Current-voltage measurements; Deep-level transient spectroscopy; and Conclusions (Electrical characteristics of SiC MIS capacitors).

  10. Electrical measurement on individual multi-walled carbon nanotubes

    Institute of Scientific and Technical Information of China (English)

    ZOU Xiao-ping; H. ABE; T. SHIMIZU; A. ANDO; H. OKUMOTO; ZHU Shen-ming; ZHOU Hao-shen

    2006-01-01

    The characterization of electrical property of multi-walled carbon nanotubes (MWCNTs) on a nanometer scale is essential for their potential application in nano-electronic devices. The MWCNTs were synthesized on Fe2O3/SiO2/Si substrate and Pt plate substrate by simple thermal chemical vapor deposition (STCVD) technique and the electrical measurements of individual MWCNT grown on silicon substrate and Pt plate substrate were performed by home-made 'nano-manipulator',respectively. According to current-voltage curves obtained in the experiments the current density that the MWCNTs can carry is calculated to be about 107 A/cm2,which is much larger than that of normal metals.

  11. Important issues facing model-based approaches to tunneling transport in molecular junctions

    CERN Document Server

    Baldea, Ioan

    2015-01-01

    Extensive studies on thin films indicated a generic cubic current-voltage $I-V$ dependence as a salient feature of charge transport by tunneling. A quick glance at $I-V$ data for molecular junctions suggests a qualitatively similar behavior. This would render model-based studies almost irrelevant, since, whatever the model, its parameters can always be adjusted to fit symmetric (asymmetric) $I-V$ curves characterized by two (three) expansion coefficients. Here, we systematically examine popular models based on tunneling barrier or tight-binding pictures and demonstrate that, for a quantitative description at biases of interest ($V$ slightly higher than the transition voltage $V_t$), cubic expansions do not suffice. A detailed collection of analytical formulae as well as their conditions of applicability are presented to facilitate experimentalists colleagues to process and interpret their experimental data by obtained by measuring currents in molecular junctions. We discuss in detail the limits of applicabili...

  12. 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.

  13. Measurements and Modeling of III-V Solar Cells at High Temperatures up to 400 degrees C

    Energy Technology Data Exchange (ETDEWEB)

    Perl, Emmett E.; Simon, John; Geisz, John F.; Lee, Minjoo Larry; Friedman, Daniel J.; Steiner, Myles A.

    2016-09-01

    In this paper, we study the performance of 2.0 eV Al0.12Ga0.39In0.49P and 1.4 eV GaAs solar cells over a temperature range of 25-400 degrees C. The temperature-dependent J01 and J02 dark currents are extracted by fitting current-voltage measurements to a two-diode model. We find that the intrinsic carrier concentration ni dominates the temperature dependence of the dark currents, open-circuit voltage, and cell efficiency. To study the impact of temperature on the photocurrent and bandgap of the solar cells, we measure the quantum efficiency and illuminated current-voltage characteristics of the devices up to 400 degrees C. As the temperature is increased, we observe no degradation to the internal quantum efficiency and a decrease in the bandgap. These two factors drive an increase in the short-circuit current density at high temperatures. Finally, we measure the devices at concentrations ranging from ~30 to 1500 suns and observe n = 1 recombination characteristics across the entire temperature range. These findings should be a valuable guide to the design of any system that requires high-temperature solar cell operation.

  14. Surface-sensitive conductivity measurement using a micro multi-point probe approach.

    Science.gov (United States)

    Perkins, Edward; Barreto, Lucas; Wells, Justin; Hofmann, Philip

    2013-03-01

    An instrument for microscale electrical transport measurements in ultra-high vacuum is presented. The setup is constructed around collinear lithographically-created multi-point probes with a contact spacing down to 500 nm. Most commonly, twelve-point probes are used. These probes are approached to the surface via piezoelectric positioners. Standard four-point resistance measurements can be performed using any combination of contacts out of the twelve available. Current/voltage measurements are taken semi-automatically for a variety of the possible contact configurations, effectively emulating measurements with an equidistant four-point probe for a wide range of contact spacings. In this way, it is possible to distinguish between bulk-like and surface-like conduction. The paper describes the design of the instrument and the approach to data and error analysis. Application examples are given for epitaxial graphene on SiC and degenerately doped Bi₂Se₃.

  15. Suprathermal plasma analyzer for the measurement of low-energy electron distribution in the ionosphere.

    Science.gov (United States)

    Shimoyama, M; Oyama, K-I; Abe, T; Yau, A W

    2011-07-01

    It is commonly believed that an energy transfer from thermal to suprathermal electrons (thermal to suprathermal energy continuously with high-energy resolution of about 0.15 eV. The measurement principle is based on the combination of a retarding potential analyzer with a channel electron multiplier (CEM) and the Druyvesteyn method, which derives energy distribution from the current-voltage characteristics. The capability of detecting plasma space potential enables absolute calibration of electron energy. The instrument with a small vacuum pump, which is required for the CEM to work in low-vacuum region, was first successfully tested by a sounding rocket S-310-37 in the ionospheric E region. The instrument is expected to provide new opportunities to measure energy distribution of thermal and non-thermal electrons in low-density plasma, where a Langmuir probe cannot measure electron temperature because of low plasma density.

  16. Schottky Diode Applications of the Fast Green FCF Organic Material and the Analyze of Solar Cell Characteristics

    Science.gov (United States)

    Çaldiran, Z.; Aydoğan, Ş.; İncekara, Ü.

    2016-05-01

    In this study, a device applications of organic material Fast Green FCF (C37H34N2Na2O10S3Na2) has been investigated. After chemical cleaning process of boron doped H-Si crystals, Al metal was coated on the one surface of crystals by thermal evaporation and fast green organic materials were coated on other surface of crystals with spin coating method (coating parameters; 800 rpm for 60 s). Finally, Ni metal was coated on Fast Green by sputtering and we obtained the Ni/Fast Green FCF/n-Si/Al Schottky type diode. And then we calculated the basic diode parameters of device with current-voltage (I-V) and capacitance- voltage (C-V) measurements at the room temperature. We calculated the ideality factory (n), barrier height (Φb) of rectifing contact from I-V measurements using thermionic emission methods. Furthermore, we calculated ideality factory (n), barrier height (Φb) and series resistance (Rs) of device using Cheung and Norde functions too. The diffusion potential, barrier height, Fermi energy level and donor concentration have been determined from the linear 1/C2-V curves at reverse bias, at room temperature and various frequencies. Besides we measured the current-voltage (I-V) at under light and analyzed the characteristics of the solar cell device.

  17. Electrically stimulated high-frequency replicas of a resonant current in GaAs/AlAs resonant-tunneling double-barrier THz nanostructures

    Science.gov (United States)

    Aleksanyan, A. A.; Karuzskii, A. L.; Kazakov, I. P.; Mityagin, Yu. A.; Murzin, V. N.; Perestoronin, A. V.; Shmelev, S. S.; Tskhovrebov, A. M.

    2016-12-01

    The periodical-in-voltage features of the negative differential conductance (NDC) region in the current-voltage characteristics of a high-quality GaAs/AlAs terahertz resonant-tunneling diode have been detected. The found oscillations are considered taking account of the LO-phonon excitation stimulated by tunneling of electrons through the quantum active region in the resonance nanostructure where an undoped quantum well layer is sandwiched between two undoped barrier layers. Rearrangements in the I-V characteristics of the resonant-tunneling diode as a consequence of the topological transformation of a measurement circuit from the circuit with the series resistance Rs to the circuit with the shunt Rp have been experimentally studied and analyzed. The revealed substantial changes in the current-voltage characteristics of the resonant-tunneling diode are discussed schematically using Kirchhoff's voltage law.

  18. Fabrication and Electrical Characterization of the Si/ZnO/ZnO:Al Structure Deposited by RF-Magnetron Sputtering

    Science.gov (United States)

    Alaya, A.; Djessas, K.; El Mir, L.; Khirouni, K.

    2016-10-01

    The electrical transport properties of the structures of Si(p)/ZnO(i)/ZnO: Al(3%) and Si(p)/PS/ZnO(i)/ZnO: Al(3%) deposited by radio-frequency-magnetron sputtering were investigated and compared by using current-voltage and impedance spectroscopy measurements in a wide temperature range of 80-300 K. Aluminum-doped ZnO is considered to be one of the most important transparent conducting oxide materials due to its high conductivity, good transparency and low cost. From the current-voltage-temperature ( I- V- T) characteristics, it was found that both structures had a good rectifying behavior. This behavior decreases according to the porous silicon layer. The variation of the conductance with frequency indicates the semiconducting behavior and superposition of different conduction mechanisms. The insertion of the porous silicon layer results in a decrease of conductivity, which is attributed to reduced conductivity of defect-rich porous silicon.

  19. 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.

  20. A physical model for the reverse leakage current in (In,Ga)N/GaN light-emitting diodes based on nanowires

    OpenAIRE

    2015-01-01

    We investigated the origin of the high reverse leakage current in light emitting diodes (LEDs) based on (In,Ga)N/GaN nanowire (NW) ensembles grown by molecular beam epitaxy on Si substrates. To this end, capacitance deep level transient spectroscopy (DLTS) and temperature-dependent current-voltage (I-V) measurements were performed on a fully processed NW-LED. The DLTS measurements reveal the presence of two distinct electron traps with high concentrations in the depletion region of the p-i-n ...

  1. Frequency and electric field controllable photodevice: FYTRONIX device

    Science.gov (United States)

    Tataroğlu, A.; Al-Sehemi, Abdullah G.; Özdemir, Mehmet; Özdemir, Resul; Usta, Hakan; Al-Ghamdi, Ahmed A.; Farooq, W. A.; Yakuphanoglu, F.

    2017-08-01

    Al/p-Si/BODIPY/Al diode was fabricated by forming BODIPY organic layer on p-Si having ohmic contact. The electrical and photoresponse properties of the prepared diode were investigated in detail. The current-voltage (I-V) measurements were performed under dark and various illumination intensities. It is observed that the photocurrent under illumination is higher than the dark current. The transient measurements indicate that the device exhibits both photodiode and photocapacitor behavior. We called this device as FYTRONIX device. The photoresponse behavior of the FYTRONIX device is controlled simultaneously by frequency and electric field. The FYRONIX device can be used as a photoresponse sensor in optoelectronic applications.

  2. Electrical properties and carrier transport mechanisms of n-ZnO/SiOx/n-Si isotype heterojunctions with native or thermal oxide interlayers

    Science.gov (United States)

    Song, Dengyuan; Guo, Baozeng

    2009-01-01

    N-type ZnO/SiOx/n-type crystalline silicon isotype heterojunctions (HJs) have been prepared by magnetron sputtering. Native and thermal oxides were employed as the interlayer between the Si substrate and the ZnO film. Transmission electron microscopy and x-ray photoelectron spectroscopy revealed that an oxide layer was inserted in the HJ interface, with thickness of ~1.2 nm (native oxide) and ~2.0 nm (thermal oxide). Atomic force microscopy and x-ray diffraction spectroscopy showed that the ZnO film on the Si substrate consists of tightly packed grains with sizes in the range 50-150 nm and is c-axis preferred orientation. The electrical properties were characterized by current-voltage (I-V), capacitance-voltage (C-V) and current-voltage-temperature (I-V-T) measurements. By a comparison of the HJ properties, the n-ZnO/thermal oxide/n-Si HJs show improved electrical properties, with a fairly low leakage current and high rectification ratio, although the series resistance increased. Studies of fitting the I-V-T measurement data suggest that the tunnelling process is a dominant current transport mechanism for the n-ZnO/native or thermal oxide/n-Si HJs at an intermediate voltage range.

  3. Electrical properties and carrier transport mechanisms of n-ZnO/SiO{sub x}/n-Si isotype heterojunctions with native or thermal oxide interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Song Dengyuan [ARC Photovoltaics Centre of Excellence, University of New South Wales, Sydney, NSW 2052 (Australia); Guo Baozeng, E-mail: s.dengy@unsw.edu.a [College of Electronic and Informational Engineering, Hebei University, Baoding 071002 (China)

    2009-01-21

    N-type ZnO/SiO{sub x}/n-type crystalline silicon isotype heterojunctions (HJs) have been prepared by magnetron sputtering. Native and thermal oxides were employed as the interlayer between the Si substrate and the ZnO film. Transmission electron microscopy and x-ray photoelectron spectroscopy revealed that an oxide layer was inserted in the HJ interface, with thickness of {approx}1.2 nm (native oxide) and {approx}2.0 nm (thermal oxide). Atomic force microscopy and x-ray diffraction spectroscopy showed that the ZnO film on the Si substrate consists of tightly packed grains with sizes in the range 50-150 nm and is c-axis preferred orientation. The electrical properties were characterized by current-voltage (I-V), capacitance-voltage (C-V) and current-voltage-temperature (I-V-T) measurements. By a comparison of the HJ properties, the n-ZnO/thermal oxide/n-Si HJs show improved electrical properties, with a fairly low leakage current and high rectification ratio, although the series resistance increased. Studies of fitting the I-V-T measurement data suggest that the tunnelling process is a dominant current transport mechanism for the n-ZnO/native or thermal oxide/n-Si HJs at an intermediate voltage range.

  4. Measurement of silicon and GaAs/Ge solar cells ac parameters

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, M.P.; Nagaraju, J. [Indian Institute of Science, Bangalore (India). Dept. of Instrumentation

    2005-01-01

    The ac parameters (cell capacitance and cell resistance) of Silicon (Si) and Gallium Arsenide (GaAs/Ge) solar cells are measured at different temperatures using time domain technique. The cell capacitance is calculated from the Open circuit voltage decay (OCVD) and the cell resistance from solar cell I-V characteristics measured under dark condition. It is observed that the solar cell capacitance increases whereas the cell resistance decreases with increase in temperature. (author)

  5. How [NOT] to Measure a Solar Cell to Get the Highest Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Emery, Keith

    2016-06-05

    The multibillion-dollar photovoltaic (PV) industry sells products by the watt; the calibration labs measure this parameter at the cell and module level with the lowest possible uncertainty of 1-2 percent. The methods and procedures to achieve a measured 50 percent efficiency on a thin-film solar cell are discussed. This talk will describe methods that ignore procedures that increase the uncertainty. Your questions will be answered concerning 'Everything you Always Wanted to Know about Efficiency Enhancements But Were Afraid to Ask.' The talk will cover a step-by-step procedure using examples found in literature or encountered in customer samples by the National Renewable Energy Laboratory's (NREL's) PV Performance Characterization Group on how to artificially enhance the efficiency. The procedures will describe methods that have been used to enhance the current voltage and fill factor.

  6. Ion temperature measurement using an ion sensitive probe in the LHD divertor plasma

    Energy Technology Data Exchange (ETDEWEB)

    Ezumi, N. E-mail: ezumi@ec.nagano-nct.ac.jp; Masuzaki, S.; Ohno, N.; Uesugi, Y.; Takamura, S

    2003-03-01

    The first reliable measurement of ion temperature in the divertor plasma of the Large Helical Device has been done by using an ion sensitive probe. The satisfactory current-voltage characteristics of the ion collector for evaluating the ion temperature were obtained at the outer part of the divertor leg. Furthermore, simultaneous ion and electron temperature measurements were successfully done in this part. The results show that the ion temperature is higher than the electron temperature in the part. There is a possibility that the profiles of the evaluated ion temperature which shows relatively higher than the electron temperature at the outside of divertor leg are qualitatively explained by particle's orbits around the edge and divertor region.

  7. Chapter 10: CPV Multijunction Solar Cell Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Osterwald, Carl R.; Siefer, Gerald

    2016-04-15

    Characterization of solar cells can be divided into two types: the first is measurement of electrooptical semiconductor device parameters, and the second is determination of electrical conversion efficiency. This chapter reviews the multijunction concepts that are necessary for understanding Concentrator photovoltaic (CPV) cell characterization techniques, and describes how CPV efficiency is defined and used. For any I-V measurement of a multijunction cell, the sun simulator spectrum has to be adjusted in a way that all junctions generate the same photocurrent ratios with respect to each other as under reference conditions. The chapter discusses several procedures for spectral irradiance adjustments of solar simulators, essential for multijunction measurements. It overviews the light sources and optics commonly used in simulators for CPV cells under concentration. Finally, the chapter talks about the cell area, quantum efficiency (QE), and current-voltage (I-V) curve measurements that are needed to characterize cells as a function of irradiance.

  8. Fosfomycin i.v. for Treatment of Severely Infected Patients

    Science.gov (United States)

    2017-02-28

    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

  9. 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

  10. Energi og klima i væksthusgartnerier

    DEFF Research Database (Denmark)

    Strøm, J.S.(red.)

    Publikationen bringer 34 artikler redigeret på grundlag af indlæggene på et seminar arrangeret af Nordiske Jordbrugsforskeres Forening. Artiklerne gør status over den nordiske energiforskning på væksthusområdet, og belyser energiforbrug set fra både tekniske, biologiske og økonomiske synsvinkler....

  11. What is left of i.v. urography?

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Palma, L. [Dept. of Radiology, University of Trieste (Italy)

    2001-06-01

    Since its introduction into clinical practice in the early 1930s, intravenous urography (IVU) was the primary imaging technique for the investigation of urinary system disorders for many years, until the advent of digital cross-sectional-imaging techniques gradually started to undermine many of its indications. Intravenous urography has been superseded for some indications such as renovascular arterial hypertension, prostatic dysuria, renal failure, palpable abdominal masses and recurrent urinary tract infection in women. Intravenous urography has been reduced, in the sense that it is no longer a primary examination, for other clinical indications such as renal colic, renal trauma, uroseptic fever, asymptomatic haematuria, medical haematuria, obstructive uropathies and follow-up of various disorders. Intravenous urography is indicated and often mandatory in congenital anomalies of the urinary tract, prior to endourological procedures, possible fistulas, renal transplantation, tuberculosis and ureteral pathology. In conclusion, IVU is still the examination of choice where there is a need to visualize the entire urinary system and to evaluate the state of the papillae and calyces. Computed tomography urography and MR urography are the imaging modalities ready in the near future to replace IVU. (orig.)

  12. 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

  13. 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

  14. Asiago eclipsing binaries program. I. V432 Aur

    CERN Document Server

    Siviero, A; Sordo, R; Dallaporta, S; Zwitter, T; Marrese, P M; Milone, E F

    2003-01-01

    The orbit and physical parameters of the previously unsolved eclipsing binary V432 Aur, discovered by Hipparcos, have been derived with errors better than 1% from extensive Echelle spectroscopy and B, V photometry. Synthetic spectral analysis of both components has been performed, yielding T_eff and log g in close agreement with the orbital solution, a metallicity [Z/Z_sun]=-0.6 and rotational synchronization for both components. Direct comparison on the theoretical L, T_eff plane with the Padova evolutionary tracks and isochrones for the masses of the two components (1.22 and 1.08 M_sun) provides a perfect match and a 3.75 Gyr age. The more massive and cooler component is approaching the base of the giant branch and displays a delta-Sct pulsation activity with an amplitude of Delta V = 0.075 mag and Delta rad.vel. = 1.5 km/sec. With a T_eff = 6080 K it is one of the coolest delta-Sct known, falling well to the red of the instability strip edge. Orbital modeling reveals a large and bright surface spot on it. ...

  15. [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.

  16. 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

  17. 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

  18. Characterization of Nanostructured n-ZnO/p-Si Heterojunction Prepared by a Simple Sol-Gel Method

    Science.gov (United States)

    He, Bo; Xu, Jing; Ning, Huanpo; Xiong, Hao; Xing, Huaizhong; Qin, Yuming

    2016-03-01

    The nanostructured ZnO film was prepared on a texturized Si wafer by a simple sol-gel method to fabricate n-ZnO/p-Si heterojunction photoelectric device. The novel sol-gel method is cheap and convenient. The structural, optical and electrical properties of the nanostructured ZnO film were studied by XRD, SEM, XPS, PL, UV-Vis spectrophotometer and Hall effect measurement. The current-voltage (I-V) curve of nanostructured ZnO/p-Si heterojunction device shows good rectifying behavior. Good photoelectric behavior is obtained.

  19. Temperature dependant electrical properties of formyl-TIPPCu(II)/p-Si heterojunction diode

    Science.gov (United States)

    Khan, Dil Nawaz; Sayyad, Muhammad Hassan; Wahab, Fazal; Tahir, Muhammad; Yaseen, Muhammad; Munawar, Munawar Ali; Ali, Mukhtar

    2014-05-01

    This paper reports the temperature dependent electrical characterization of formyl-TIPPCu(II)/p-Si heterojunction diode which was fabricated by growing thin films of formyl-TIPPCu(II) on the p-type silicon substrate by thermal sublimation technique. The variation in electrical characteristics of the fabricated devices has been systematically investigated as the function of temperature by using current-voltage (I-V) measurements in the temperature range 299-339 K. The diode parameters like ideality factor, zero bias barrier height and parasitic series resistance have been found to be strongly temperature dependant. The zero bias barrier height increases while ideality factor and series resistance decreases with increasing temperature.

  20. 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.

  1. Analysis of Deep Level Defects in GaN p-i-n Diodes after Beta Particle Irradiation

    OpenAIRE

    2015-01-01

    The effect of beta particle irradiation (electron energy 0.54 MeV) on the electrical characteristics of GaN p-i-n diodes is investigated by current-voltage (I-V), capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS) measurements. The experimental studies show that, for the as-grown samples, three electron traps are found with activation energies ranging from 0.06 to 0.81 eV and concentrations ranging from 1.2 × 1014 to 3.6 × 1015 cm−3, together with one hole trap with energy...

  2. Capacitance-frequency Spectrum Characterization of Organics/Metal Schottky Diodes

    Institute of Scientific and Technical Information of China (English)

    GUO Wen-ge; ZHANG Yan-cao; ZHANG Shou-gang

    2006-01-01

    An organics/metal Schottky diode is fabricated using 3, 4∶9, 10-perylenetetracarboxylic-dianhydride(PTCDA) thin film sandwiched between ITO and Au by simple thermal evaporation technique. The current-voltage(I-V) characteristics are investigated at room temperature in open air. The results show the rectification ratio is in excess of 100. From the capacitance-frequency(C-f) and capacitance-voltage(C-V) measurements, the Schottky barrier height between 0.2~0.3 eV is obtained according to standard Schottky theory.

  3. 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.

  4. Growth, Structural, and Electrical Characterizations of N-Polar InAlN by Plasma-Assisted Molecular Beam Epitaxy

    Science.gov (United States)

    Dasgupta, Sansaptak; Nidhi; Choi, Soojeong; Wu, Feng; Speck, James S.; Mishra, Umesh K.

    2011-04-01

    N-polar InxAl1-xN (0.02 560 °C. A smooth surface morphology was obtained for In0.18Al0.82N lattice-matched to GaN. Subsequently, N-polar In0.18Al0.82N was used as a charge-inducing barrier in a N-polar GaN HEMT structure and electrical characterizations including current-voltage (I-V) measurements were performed.

  5. Degradation of bulk diffusion length in CZ silicon solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Reiss, J.H.; King, R.R.; Mitchell, K.W. [Siemens Solar Industries, Camarillo, CA (United States)

    1995-08-01

    Commercially-produced, unencapsulated, CZ silicon solar cells can lose 3 to 4% of their initial efficiency after exposure to light. After this initial, rapid ( < 30 min.) decrease, the cell power output remains stable. The cell performance recovers in a matter of hours in the dark at room temperature, and degrades again under light exposure. The different conditions under which CZ silicon cells degrade, and the reverse process, annealing, are characterized with the methods of spectral response and current-voltage (I-V) measurements. Iron impurities are a possible cause of this effect.

  6. 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.

  7. Thermal behavior of a high power generator exciter bridge measured by optical fiber sensors

    Science.gov (United States)

    Probst, Werner K.; Bortolotti, Fernando; de Morais Sousa, Kleiton; Kalinowski, Hypolito José; Martelli, Cicero; Cardozo da Silva, Jean Carlos

    2013-05-01

    This paper presents temperature measurements taken at a 3-phase thyristor rectifier bridge in a synchronous generator using fiber Bragg grating (FBG) sensors applied directly on the thyristors upper surface. The results show the thermal behavior of the thyristors during the generator's start-up-phase and the period of time after the synchronization, with regulating operations as reaction to different load conditions. The temperature analysis is supported by current, voltage and power values of the hydroelectric power plant monitoring system. The trend of curves describes the typical behavior of thyristors which is proven with a four term transient thermal model. The different heat effect a thyristor experiences inside the switching-cabinet are also discussed.

  8. Current-voltage and kinetic energy flux relations for relativistic field-aligned acceleration of auroral electrons

    Directory of Open Access Journals (Sweden)

    S. W. H. Cowley

    2006-03-01

    Full Text Available Recent spectroscopic observations of Jupiter's "main oval" auroras indicate that the primary auroral electron beam is routinely accelerated to energies of ~100 keV, and sometimes to several hundred keV, thus approaching the relativistic regime. This suggests the need to re-examine the classic non-relativistic theory of auroral electron acceleration by field-aligned electric fields first derived by Knight (1973, and to extend it to cover relativistic situations. In this paper we examine this problem for the case in which the source population is an isotropic Maxwellian, as also assumed by Knight, and derive exact analytic expressions for the field-aligned current density (number flux and kinetic energy flux of the accelerated population, for arbitrary initial electron temperature, acceleration potential, and field strength beneath the acceleration region. We examine the limiting behaviours of these expressions, their regimes of validity, and their implications for auroral acceleration in planetary magnetospheres (and like astrophysical systems. In particular, we show that for relativistic accelerating potentials, the current density increases as the square of the minimum potential, rather than linearly as in the non-relativistic regime, while the kinetic energy flux then increases as the cube of the potential, rather than as the square.

  9. Charging of superconducting layers and resonance-related hysteresis in the current-voltage characteristics of coupled Josephson junctions

    Science.gov (United States)

    Shukrinov, Yu. M.; Gaafar, M. A.

    2011-09-01

    A manifestation of a resonance-type hysteresis related to the parametric resonance in the system of coupled Josephson junctions is demonstrated. In contrast with the McCumber and Steward hysteresis, we find that the width of this hysteresis is inversely proportional to the McCumber parameter and it also depends on the coupling between junctions and the boundary conditions. Investigation of the time dependence of the electric charge in superconducting layers allows us to explain the origin of this hysteresis by different charge dynamics for increasing and decreasing bias current processes. The effect of the wavelength of the longitudinal plasma wave created at the resonance on the charging of superconducting layers is demonstrated. We find a strong effect of the dissipation in the system on the amplitude of the charge oscillations at the resonance.

  10. 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 stream_source_info masilela_1998.pdf.txt stream_content_type text/plain stream_size 11826 Content-Encoding ISO-8859-1 stream_name masilela_1998.pdf.txt Content-Type text/plain; charset=ISO-8859-1 En`ineerin` Failure... used on new pipelines as a good quality control tool[ The bene_ts of using the DCVG technique on new pipelines is clearly evident as more than 79) of coating defects were a direct result of mechanical damage during construction[ On such evidence...

  11. 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...... a widening of the surface band gap by 1 eV with respect to the gap of the substrate, while a significant narrowing of the gap was observed for nanocrystals on p-Si:H. This experimental result could be explained by modeling the system as a metal-insulator-semiconductor (MIS) diode. Using this model we have...

  12. 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

    )] in the millimeter and submillimeter range. The study is performed in the frame of a modified sine-Gordon model, which includes surface losses, self-pumping effect, and in an empirical way the superconducting gap. The electromagnetic coupling to the environment is modeled by a simple resistor-capacitor load (RC load...

  13. 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

    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...... forward voltages, the diode current is increased with increased NA, but for higher forward voltages, the diode current is decreased as NA is increased. For the diodes examined in this work, the results presented lead to the conclusion that the diode current should be treated as a superposition...... 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...

  14. Reply to "Comment on 'Electrical Conductivity and Current-Voltage Characteristics of Individual Conducting Polymer PEDOT Nanowires'"

    Institute of Scientific and Technical Information of China (English)

    LONG Yun-Ze

    2009-01-01

    @@ Recently we reported electrical properties of an individual PEDOT nanowire.[1] Ohlckers and Pipinys[2]suggested that the temperature-behavior of Ⅰ- Ⅴcurves and resistance can be described in the framework of a phonon-assisted tunneling (PhAT) model.

  15. Nonlinear current-voltage characteristics due to quantum tunneling of phase slips in superconducting Nb nanowire networks

    Energy Technology Data Exchange (ETDEWEB)

    Trezza, M.; Cirillo, C.; Sabatino, P.; Carapella, G.; Attanasio, C. [CNR-SPIN Salerno and Dipartimento di Fisica “E. R. Caianiello”, Università degli Studi di Salerno, Fisciano I-84084 (Italy); Prischepa, S. L. [Belarusian State University of Informatics and Radioelectronics, P. Browka 6, Minsk 220013 (Belarus)

    2013-12-16

    We report on the transport properties of an array of N∼30 interconnected Nb nanowires, grown by sputtering on robust porous Si substrates. The analyzed system exhibits a broad resistive transition in zero magnetic field, H, and highly nonlinear V(I) characteristics as a function of H, which can be both consistently described by quantum tunneling of phase slips.

  16. An Efficient approach for Shielding Effect of the Grounding Electrodes under Impulse-Current Voltage based on MATLAB

    Directory of Open Access Journals (Sweden)

    Kalyani Pole

    2012-06-01

    Full Text Available The lightning current waveform has a major influence on the dynamic performance of ground electrodes. While high lightning current intensity improves the dynamic grounding performance due to ionization of the soil, very fast fronted pulses might worsen the performance in case of inductive behaviour. The previous analysis has often been based on quasistatic approximation that is not applicable to very fast fronted pulses. Previous Research focused on analyzing the impulse current dispersal regularity of different branches when injecting at one point. Comparing with the leakage current distribution of a single ground electrode, it is found that the leakage currents along the branches increase with the distance to the current feed point, and the more conductors near the injection point, the more uneven the leakage current distribution is. In this paper by simulation result we indicate that shielding effect should be taken into account when analyzing the impulse characteristics of grounding electrodes. Based on the simulation results, new empirical formulas applicable for slow and very fast fronted lightning current pulses are proposed. The effects of the ionization of the soil are disregarded; therefore, the new formulas are applicable for a conservative estimate of the upper bound of the impulse impedance of ground electrodes. In this paper we also analyze and compare by the MATLAB. We also provide dynamic behavior of ground electrodes.

  17. An Efficient approach for Shielding Effect of the Grounding Electrodes under Impulse-Current Voltage based on Matlab

    Directory of Open Access Journals (Sweden)

    Ms. Kalyani Pole

    2012-06-01

    Full Text Available The lightning current waveform has a majorinfluence on the dynamic performance of groundelectrodes. While high lightning current intensityimproves the dynamic grounding performance dueto ionization of the soil, very fast fronted pulsesmight worsen the performance in case of inductivebehaviour. The previous analysis has often beenbased on quasistatic approximation that is notapplicable to very fast fronted pulses. PreviousResearch focused on analyzing the impulse currentdispersal regularity of different branches wheninjecting at one point. Comparing with the leakagecurrent distribution of a single ground electrode, itis found that the leakage currents along thebranches increase with the distance to the currentfeed point, and the more conductors near theinjection point, the more uneven the leakagecurrent distribution is. In this paper by simulationresult we indicate that shielding effect should betaken into account when analyzing the impulsecharacteristics of grounding electrodes. Based onthe simulation results, new empirical formulasapplicable for slow and very fast fronted lightningcurrent pulses are proposed. The effects of theionization of the soil are disregarded; therefore, thenew formulas are applicable for a conservativeestimate of the upper bound of the impulseimpedance of ground electrodes. In this paper wealso analyze and compare by the MATLAB. We alsoprovide dynamic behavior of ground electrodes.

  18. 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.

  19. Influence of Different Sol-gel Spin Coating Speed on Memristive Behaviour of Pt/TiO2/ZnO/ITO Device

    Science.gov (United States)

    Kasim, S. M. M.; Shaari, N. A. A.; Bakar, R. A.; Aznilinda, Z.; Mohamad, Zulfakri; Herman, S. H.

    2015-11-01

    Composite titanium dioxide (TiO2) and zinc oxide (ZnO) thin films were deposited on indium tin oxide (ITO) substrates using sol-gel spin coating technique. The electrical and physical characterizations of three different sol-gel spin coating speed were investigated using two-probe current-voltage (I-V) measurement, field emission scanning electron microscopy (FESEM) and surface profiler (SP) respectively. The I-V measurement results showed the pinched hysteresis loop for every single of devices thus indicate that all the devices are memristive. ROFF/RON ratio which was defined from the hysteresis loop of device with higher spin speed was slightly higher compared to others.

  20. Bulk electrical properties of single-walled carbon nanotubes immobilized by dielectrophoresis: evidence of metallic or semiconductor behavior.

    Science.gov (United States)

    Mureau, Natacha; Watts, Paul C P; Tison, Yann; Silva, S Ravi P

    2008-06-01

    We report the electrical characterization of single-walled carbon nanotubes (SWCNTs) trapped between two electrodes by dielectrophoresis (DEP). At high frequency, SWCNTs collected by DEP are expected to be of metallic type. Indeed current-voltage (I-V) measurements for devices made at 10 MHz show high values of conductivity and exhibit metallic behavior with linear and symmetric electrical features attributed to ohmic conduction. At low frequency, SWCNTs attracted by DEP are expected to be of semiconducting nature. Devices made at 10 kHz behave as semiconductors and demonstrate nonlinear and rectifying electrical characteristics with conductivities many orders of magnitude below the sample resulting from high-frequency immobilization of SWCNTs. Conducting atomic force microscopy (C-AFM) and current density calculation results are presented to reinforce results obtained by I-V measurements which clearly show type separation of SWCNTs after DEP experiments.

  1. The electric properties and the current-controlled differential negative resistance of cBN crystal

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The electric properties of nonintentionally doped n-cubic boron nitride(cBN) crystal are investigated.The cBN crystal was transformed from hexagonal-boron nitride(h-BN) under high pressure(HP) and high temperature(HT) using magnesium powder as catalyst.At room temperature,the current-voltage(I-V) characteristics of cBN crystal are measured and found to be nonlinear.When the electric field is in the range of(1―1.5)×105 V/cm,the avalanche breakdown occurs inside the whole cBN crystal.At this same time,the bright blue-violet with the wavelength of 380―400 nm from the cBN crystal is observed.When measuring the I-V curve after breakdown of cBN crystal,the current-controlled differential negative resistance phenomenon is observed.The breakdown is repeatable.

  2. In-Situ Measurement of Power Loss for Crystalline Silicon Modules Undergoing Thermal Cycling and Mechanical Loading Stress Testing: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Spataru, Sergiu; Hacke, Pater; Sera, Dezso

    2015-09-15

    We analyze the degradation of multi-crystalline silicon photovoltaic modules undergoing simultaneous thermal, mechanical, and humidity stress testing to develop a dark environmental chamber in-situ measurement procedure for determining module power loss. From the analysis we determine three main categories of failure modes associated with the module degradation consisting of: shunting, recombination losses, increased series resistance losses, and current mismatch losses associated with a decrease in photo-current generation by removal of some cell areas due to cell fractures. Based on the analysis, we propose an in-situ module power loss monitoring procedure that relies on dark current-voltage measurements taken during the stress test, and initial and final module flash testing, to determine the power degradation characteristic of the module.

  3. In-Situ Measurement of Power Loss for Crystalline Silicon Modules Undergoing Thermal Cycling and Mechanical Loading Stress Testing: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Spataru, Sergiu; Hacke, Pater; Sera, Dezso

    2015-09-15

    We analyze the degradation of multi-crystalline silicon photovoltaic modules undergoing simultaneous thermal, mechanical, and humidity stress testing to develop a dark environmental chamber in-situ measurement procedure for determining module power loss. From the analysis we determine three main categories of failure modes associated with the module degradation consisting of: shunting, recombination losses, increased series resistance losses, and current mismatch losses associated with a decrease in photo-current generation by removal of some cell areas due to cell fractures. Based on the analysis, we propose an in-situ module power loss monitoring procedure that relies on dark current-voltage measurements taken during the stress test, and initial and final module flash testing, to determine the power degradation characteristic of the module.

  4. 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.

  5. Carrier transport mechanisms of bistable memory devices fabricated utilizing core-shell CdSe/ZnSe quantum-dot/multi-walled carbon nanotube hybrid nanocomposites

    Science.gov (United States)

    Li, Fushan; Ick Son, Dong; Kim, Tae Whan; Ryu, Euidock; Kim, Sang Wook

    2009-02-01

    Transmission electron microscopy images showed that conjugation between single core-shell CdSe/ZnSe quantum dots (QDs) and oxidized multi-walled carbon nanotubes (MWCNTs) was achieved through the complexation reaction. Current-voltage (I-V) measurements on Al/CdSe:MWCNT conjugated nanocomposite/indium-tin-oxide devices at 300 K showed that the on/off ratio of the current bistability was as large as about 104, which was significantly increased due to an enhancement of the carrier transfer efficiency between the CdSe/ZnSe QDs and the MWCNTs. Carrier transport mechanisms of the bistable memory devices fabricated utilizing CdSe/ZnSe QD/MWCNT hybrid nanocomposite are described on the basis of the I-V results.

  6. Improvement on electrical properties of screen-printed silicon solar cells by light-induced electroplating of silver

    Science.gov (United States)

    Li, Tao; Wang, Wenjing

    2016-10-01

    The total power losses are analyzed based on two-layer electrode of light-induced electroplating after screen printing. By the introduction of scale factor in the calculation, optical losses are closer to the actual condition. Optimized two-layer contact of front side could diminish power losses distinctly and improve the current-voltage (I-V) characteristic of crystalline silicon solar cells. The relative increments of I-V parameters as a function of electroplating time are measured. The quantitative comparison of analytical results between half-ellipse shape model and half-circled shape model is performed. The numerical simulation results and experimental data show good agreement. Due to the successful verification, the simulation results could be used to optimize the two-layer electrode structure and light-induced electroplating process.

  7. International round-robin inter-comparison of dye-sensitized and crystalline silicon solar cells

    Science.gov (United States)

    Chen, Chia-Yuan; Ahn, Seung Kyu; Aoki, Dasiuke; Kokubo, Junichi; Yoon, Kyung Hoon; Saito, Hidenori; Lee, Kyung Sik; Magaino, Shinichi; Takagi, Katsuhiko; Lin, Ling-Chuan; Lee, Kun-Mu; Wu, Chun-Guey; Zhou, Hong; Igari, Sanekazu

    2017-02-01

    An international round-robin inter-comparison of the spectral responsivity (SR) and current-voltage (I-V) characteristics for dye-sensitized solar cells (DSCs) and crystalline silicon solar cells is reported for the first time. The crystalline silicon cells with various spectral responsivities were also calibrated by AIST to validate this round-robin activity. On the basis of the remarkable consistency in Pmax (within ±1.4% among participants) and Isc (within ±1.2% compared to the primary calibration of AIST) of the silicon specimens, the discrepancy in the SR and photovoltaic parameters of five DSCs among three national laboratories can be verified and diagnosed. Recommendations about sample packages, SR and I-V measurement methods as well as the inter-comparison protocol for improving the performance characterization of the mesoscopic DSCs are presented according to the consolidated data and the experience of the participants.

  8. The morphological characterizations of titanium dioxide (TiO2) via sol-gel method

    Science.gov (United States)

    Nordin, N. K. S.; Hashim, U.; Vijayakumaran, T.

    2017-03-01

    Titanium Dioxide (TiO2) has comes with many fascinating properties in environmental purification, photocatalytic activity and in sensor application. TiO2 is prepared by sol-gel method and been coated on the silicon oxide (SiO) and glasses for 1 layer, 3 layers, 5 layers and finally 7 layers to find the best layer for coating purpose. A few characterizations had been carried out such as Scanning Electron Microscope (SEM), Photoluminescence (PL) and Current-Voltage (I-V) measurement for TiO2. The I-V recorded for the presence of Interdigitated Electrode (IDE) is 2.46×10-10 at 1V increased from 2.24×10-10 without the coating of TiO2. TiO2 coated on IDE triggered more sensitive sensor compared to IDE without metal oxides coated.

  9. Bipolar resistive switching and conduction mechanism of an Al/ZnO/Al-based memristor

    Science.gov (United States)

    Gul, Fatih; Efeoglu, Hasan

    2017-01-01

    In this study, a direct-current reactive sputtered Al/ZnO/Al-based memristor device was fabricated and its resistive switching (RS) characteristics investigated. The optical and structural properties were confirmed by using UV-vis spectrophotometry and x-ray diffraction, respectively. The memristive and resistive switching characteristics were determined using time dependent current-voltage (I-V-t) measurements. The typical pinched hysteresis I-V loops of a memristor were observed. In addition, the device showed forming-free, uniform and bipolar RS behavior. The low electric field region exhibited ohmic conduction, while the Schottky emission (SE) was found to be the dominant conduction mechanism in the high electric field region. A weak Poole-Frenkel (PF) emission also appeared. In conclusion, it was suggested that the SE and PF mechanisms were related to the oxygen vacancies in the ZnO.

  10. High electronic couplings of single mesitylene molecular junctions.

    Science.gov (United States)

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

    2015-01-01

    We report on an experimental analysis of the charge transport properties of single mesitylene (1,3,5-trimethylbenzene) molecular junctions. The electronic conductance and the current-voltage characteristics of mesitylene molecules wired into Au electrodes were measured by a scanning tunnelling microscopy-based break-junction method at room temperature in a liquid environment. We found the molecular junctions exhibited two distinct conductance states with high conductance values of ca. 10(-1) G 0 and of more than 10(-3) G 0 (G 0 = 2e (2)/h) in the electronic conductance measurements. We further performed a statistical analysis of the current-voltage characteristics of the molecular junctions in the two states. Within a single channel resonant tunnelling model, we obtained electronic couplings in the molecular junctions by fitting the current-voltage characteristics to the single channel model. The origin of the high conductance was attributed to experimentally obtained large electronic couplings of the direct π-bonded molecular junctions (ca. 0.15 eV). Based on analysis of the stretch length of the molecular junctions and the large electronic couplings obtained from the I-V analysis, we proposed two structural models, in which (i) mesitylene binds to the Au electrode perpendicular to the charge transport direction and (ii) mesitylene has tilted from the perpendicular orientation.

  11. Influence of Edge-Doping on I-V Curve of Zigzag-Edge Graphene Nanoribbons under Uniaxial Strain%边缘掺杂对应力作用下锯齿型石墨烯纳米带I-V特性的影响

    Institute of Scientific and Technical Information of China (English)

    廖文虎; 郭俊吉

    2012-01-01

    A systematic first-principles calculations on the I-V curve of n-type nitrogen (N) and p-type oxygen (0) edge dopant 6-zigzag-edge graphene nanoribbons (6-ZGNR) under an external uniaxial strain was obtained. It is demonstrated that the conducting ability of 6-ZGNR may be enhanced a little by edge doping in the FBias 1. 0 V, while the external uniaxial strain strengthens the conducting ability of 6-ZGNR in a wide bias voltage range. The results are proposed to be useful in the design of nanoscale electronic/optoelectronic devices based on ZGNRs.%利用第一性原理计算得到边缘n-型氮N和p-型氧O掺杂的6-锯齿型石墨烯纳米带在外加非轴向应力作用下的I-V特性曲线.研究结果表明,边缘掺杂在低偏压条件(VBias<0.5 V)下增强锯齿型石墨烯纳米带的导电能力,在偏压大于1.0V后将减弱系统的导电能力;外加非轴向应变却能在较宽的偏压范围内增强系统的导电能力.该结果对基于锯齿型石墨烯纳米带的纳米电子、光电子器件的研究和设计具有较重要的意义.

  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. Pharmacokinetic study on compound aluminum sulfate injection after i.v. and in situ administration in rabbits%复方硫酸铝注射液新西兰兔静脉注射和局部注射药代动力学研究

    Institute of Scientific and Technical Information of China (English)

    徐风华; 陈宜鸿; 方翼; 高秀云

    2006-01-01

    目的:研究复方硫酸铝注射液静脉注射后的药代动力学以及肌肉和皮下注射后的全身吸收.方法:兔耳静脉、股四头肌和背部皮下注射,耳静脉采血,采用等离子体质谱法测定血铝浓度,DAS药代动力学程序处理血药浓度数据.结果:静脉注射复方硫酸铝注射液1 mg·kg-1 (剂量均以无水硫酸铝计),硫酸铝体内药代动力学过程符合二房室模型,t1/2β为 1.08±0.46 h,AUC0-12h为 1.52±0.92 mg·h·L-1(n=5).股四头肌注射复方硫酸铝注射液80 mg·kg-1,血铝浓度略有升高,但不明显,采用梯形法计算曲线下面积,平均AUC0-24h为 2.93±1.82 mg·h·L-1(n=5),相对生物利用度约为 2.41%.皮下注射160 mg·kg-1,血铝浓度没有明显的峰值,平均AUC0-24h为 0.88±1.14 mg·h·L-1(n=5),相对生物利用度约为 0.36%.结论:复方硫酸铝注射液静脉注射后血液中清除速率快,局部注射后全身吸收量很低,是一种安全的新制剂.%AIM: To study the pharmacokinetics of compound aluminum sulfate injection after i.v. administration and aluminum absorption after i.m. and s.c. administration in New Zealand rabbits. METHODS: Compound aluminum sulfate injection was administrated i.v. to the left-ear at the dose of 1 mg·kg-1, i.m. in quadriceps at the dose of 80 mg·kg-1 or s.c. under back skin at the dose of 160 mg·kg-1 (anhydrous aluminum sulfate/body weight). Blood samples were collected at different time after injection from the right-ear vein. ICP-MS assay was used to determine the aluminum (Al) concentration. Pharmacokinetic parameters were calculated with DAS program. RESULTS: The blood Al concentration-time profiles after i.v. injection fitted to a two-compartment model, with t1/2β 1.08±0.46 h and AUC0-12h 1.52±0.92 mg·h·L-1 (n=5). There was no obvious increase in Al concentration after i.m. injection of 80 mg·kg-1 or s.c. injection of 160 mg·kg-1 aluminum sulfate. The average AUC0-24h of i.m. injection was 2.93±1.82 mg·h·L-1

  14. Ultrasonic Spray Pyrolysis Deposited Copper Sulphide Thin Films for Solar Cell Applications

    Directory of Open Access Journals (Sweden)

    Y. E. Firat

    2017-01-01

    Full Text Available Polycrystalline copper sulphide (CuxS thin films were grown by ultrasonic spray pyrolysis method using aqueous solutions of copper chloride and thiourea without any complexing agent at various substrate temperatures of 240, 280, and 320°C. The films were characterized for their structural, optical, and electrical properties by X-ray diffraction (XRD, scanning electron microscopy (SEM, energy dispersive analysis of X-rays (EDAX, atomic force microscopy (AFM, contact angle (CA, optical absorption, and current-voltage (I-V measurements. The XRD analysis showed that the films had single or mixed phase polycrystalline nature with a hexagonal covellite and cubic digenite structure. The crystalline phase of the films changed depending on the substrate temperature. The optical band gaps (Eg of thin films were 2.07 eV (CuS, 2.50 eV (Cu1.765S, and 2.28 eV (Cu1.765S–Cu2S. AFM results indicated that the films had spherical nanosized particles well adhered to the substrate. Contact angle measurements showed that the thin films had hydrophobic nature. Hall effect measurements of all the deposited CuxS thin films demonstrated them to be of p-type conductivity, and the current-voltage (I-V dark curves exhibited linear variation.

  15. Measuring unrecorded measurement

    Science.gov (United States)

    Revzen, M.; Mann, A.

    2016-08-01

    Projective (von Neumann) measurement of an operator (i.e., a dynamical variable) selected from a prescribed set of operators is termed unrecorded measurement (URM) when both the selected operator and the measurement outcome are unknown, i.e., “lost”. Within classical physics a URM is completely inconsequential: the state is unaffected by measurement. Within quantum physics a measurement leaves a mark. The present study provides protocols that allow the retrieval of some of the data lost in a URM. The study is shown as supportive of viewing quantum measurement as made up of both classical-like and pure quantum components.

  16. 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.

  17. Accurate surface potential determination in Schottky diodes by the use of a correlated current and capacitance voltage measurements.Application to n-InP

    Institute of Scientific and Technical Information of China (English)

    Ali Ahaitouf; Abdelaziz Ahaitouf; Jean Paul Salvestrini; Hussein Srour

    2011-01-01

    Based on current voltage (I-Vg) and capacitance voltage (C-Vg) measurements,a reliable procedure is proposed to determine the effective surface potential Vd (Vg) 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-Vg measurements.The study clearly shows that the depletion width and the flat band barrier height deduced from C-Vg,which are important parameters directly related to the surface potential in the semiconductor,should be estimated within our approach to obtain more reliable information.

  18. Measurement of CuInSe{sub 2} solar cell AC parameters

    Energy Technology Data Exchange (ETDEWEB)

    Deshmukh, M.P.; Nagaraju, J. [Solar Energy and Thermodynamics Laboratory, Department of Instrumentation, Indian Institute of Science, Bangalore 560 012 (India)

    2005-01-31

    The AC parameters (cell capacitance and cell resistance) of Copper Indium Diselenide (CuInSe{sub 2}) solar cell are measured using time-domain technique. The cell capacitance is calculated from the open circuit voltage decay (OCVD) and cell resistance with solar cell I-V characteristics measured in dark. The solar cell exhibits high parallel resistance and low parallel capacitance. The doping concentration and built in voltage are derived from the 1/C{sub P}{sup 2} versus bias voltage graph. The built-in voltage of the solar cell shows good agreement with measurements published in the literature.

  19. Simultaneous Measurement of Nonlinearity and Electrochemical Impedance for Protein Sensing Using Two-Tone Excitation

    Science.gov (United States)

    Daniels, Jonathan S.; Anderson, Erik P.; Lee, Thomas H.; Pourmand, Nader

    2009-01-01

    Impedance biosensors detect the binding of a target to an immobilized probe by quantifying changes in the impedance of the electrode-electrolyte interface. The interface's I-V relationship is inherently nonlinear, varying with DC bias, and target binding can alter the degree of nonlinearity. We propose and demonstrate a method to simultaneously measure the nonlinearity and conventional small-signal impedance using intermodulation products from a two-tone input. Intermodulation amplitudes accurately reflect the impedance's manually-measured voltage dependence. We demonstrate that changes in nonlinearity can discriminate protein binding. Our measurements suggest that target binding can alter nonlinearity via the voltage dependence of the ionic double layer. PMID:19164024

  20. 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.

  1. Investigation of electrical and optoelectronic properties of zinc oxide nanowires

    Science.gov (United States)

    Zhang, D.; Lee, S. K.; Chava, S.; Berven, C. A.; Katkanant, V.

    2011-10-01

    Zinc oxide (ZnO) nanowires have been synthesized by using tubular furnace chemical vapor deposition technique. The morphology, chemical composition and crystal structure of as-synthesized ZnO nanowires were examined by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) techniques. Four-terminal current-voltage ( I- V) measurements were employed to study the electrical conductance of ZnO nanowires under various testing gas environments for gas sensing purpose. The I- V curves at temperature ranging from 150 to 300 K were recorded in the testing chamber under vacuum. The Arrhenius plot shows perfect linear relationship between the logarithm of the current I and inverse temperature 1/ T. The donor level of the semiconducting nanowires is about 326 meV. The I- V behaviors were found to be reversible and repeatable with testing gases. The electrical conductivity was enhanced by a factor of four with ambient CO gas compared to that in vacuum and other testing gases. The optoelectronic properties of the ZnO nanowires were obtained by two-terminal I- V measurement method while the nanowires were illuminated by a ruby laser. The electrical conductivity was increased by 60% when the laser was present in comparison to that when the laser was off. Those significant changes suggest that nano-devices constructed by the ZnO nanowires could be used in gas sensing and optical switching applications.

  2. Electrical investigation of the Al/porous Si/p{sup +}-Si heterojunction

    Energy Technology Data Exchange (ETDEWEB)

    Cherif, A. [Universite de Sousse, Laboratoire Energie-Materiaux, Ecole Superieure des Sciences et de la Technologie, Rue Lamine Abessi 4011, Hammam Sousse (Tunisia); Jomni, S. [Laboratoire Materiaux, Organisation et Proprietes, Faculte des Sciences de Tunis (Tunisia); Hannachi, R. [Universite de Sousse, Laboratoire Energie-Materiaux, Ecole Superieure des Sciences et de la Technologie, Rue Lamine Abessi 4011, Hammam Sousse (Tunisia); Laboratoire Materiaux, Organisation et Proprietes, Faculte des Sciences de Tunis (Tunisia); Universite de Sousse, Equipe de recherche caracterisations optoelectronique et spectroscopique des materiaux et nanomateriaux pour les telecommunications et capteurs, ISITCOM 4011, Hammam Sousse (Tunisia); and others

    2013-01-15

    Porous silicon based Al/porous Si/p{sup +}-Si heterojunction with porous silicon layer was fabricated on low-resistivity crystalline silicon substrate by electrochemical anodisation. Measurements of the current-voltage I(V) characteristics and capacitance-voltage C(V) at various frequencies were used for the investigation of the electrical properties of this heterojunction. The forward bias I(V) dependencies exhibited a high value of the quality factor close to 7. This was attributed to the existence of interfacial layer and interface states which cause the forward I(V) characteristic not to obey the ideal Schottky diode characteristic. Therefore, it was demonstrated that the current has a square root dependence on the forward bias and it was governed by the Richardson-Schottky conduction mechanism. Furthermore, an ideality factor near the unity has been obtained in the reverse current and the I(V) characteristics were governed by the porous Si/Si heterojunction. The C(V) measurement was performed at different frequencies and revealed that the capacitance behavior was typical of material with interface states. The density of interface states was found to vary from 2 Multiplication-Sign 10{sup 10} eV{sup -1}cm{sup -2} to 1.1 Multiplication-Sign 10{sup 11} eV{sup -1}cm{sup -2} as a function of the interface states energy level position in the band gap of the porous silicon.

  3. Measurement of volt-ampere characteristics of the SiPM on wafer level with setup based on the PA200 BlueRay probe station

    Science.gov (United States)

    Popova, Elena; Buzhan, Pavel; Kayumov, Fred; Stifutkin, Alexey

    2017-01-01

    Setup for measurement of volt-ampere characteristics of the Silicon photomultipliers (SiPMs) on wafer level consisting of the probe station PA200 BlueRay with embedded computer and SourceMeter Keithley 2400 was built. The setup is controlled by the homegrown software which allows adjustment of the measurements accuracy and speed. Firstly, complete I-V curves for a few samples of the chosen SiPM structure on the wafer are measured. Based on it the range of breakdown voltage and current level are defined which are used to correct the software settings. After that the whole wafer scan is made. The resulting I-V curves are used for SiPM selection (sorting) by current value at some predefined overvoltage (the difference between applied voltage and the breakdown one). Breakdown voltage is defined as: max ((dI/dU)/I).

  4. Measurement of carrier transport and recombination parameter in heavily doped silicon

    Science.gov (United States)

    Swanson, Richard M.

    1986-01-01

    The minority carrier transport and recombination parameters in heavily doped bulk silicon were measured. Both Si:P and Si:B with bulk dopings from 10 to the 17th and 10 to the 20th power/cu cm were studied. It is shown that three parameters characterize transport in bulk heavily doped Si: the minority carrier lifetime tau, the minority carrier mobility mu, and the equilibrium minority carrier density of n sub 0 and p sub 0 (in p-type and n-type Si respectively.) However, dc current-voltage measurements can never measure all three of these parameters, and some ac or time-transient experiment is required to obtain the values of these parameters as a function of dopant density. Using both dc electrical measurements on bipolar transitors with heavily doped base regions and transients optical measurements on heavily doped bulk and epitaxially grown samples, lifetime, mobility, and bandgap narrowing were measured as a function of both p and n type dopant densities. Best fits of minority carrier mobility, bandgap narrowing and lifetime as a function of doping density (in the heavily doped range) were constructed to allow accurate modeling of minority carrier transport in heavily doped Si.

  5. 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.

  6. Comparison of the measured and modelled electron densities and temperatures in the ionosphere and plasmasphere during 20-30 January, 1993

    Directory of Open Access Journals (Sweden)

    A. V. Pavlov

    is used. The deviations from the Boltzmann distribution for the first five vibrational levels of N2(<i>v and O2(<i>v were calculated. The present study suggests that these deviations are not significant at the first vibrational levels of N2 and O2 and the second level of O2, and the calculated distributions of N2(<i>v and O2(<i>v are highly non-Boltzmann at vibrational levels <i>v > 2. The resulting effect of N2(<i>v > 0 and O2(<i>v > 0 on NmF2 is the decrease of the calculated daytime NmF2 up to a factor of 1.5. The modelled electron temperature is very sensitive to the electron density, and this decrease in electron density results in the increase of the calculated daytime electron temperature up to about 580 K at the F2 peak altitude giving closer agreement between the measured and modelled electron temperatures. Both the daytime and night-time densities are not reproduced by the model without N2(<i>v > 0 and O2(<i>v > 0, and inclusion of vibrationally excited N2 and O2 brings the model and data into better agreement.

    Key words: Ionosphere (ionospheric disturbances; ionosphere-magnetosphere interactions; plasma temperature and density

     

  7. Measures for Measures

    DEFF Research Database (Denmark)

    Jørgensen, Sune Lehman; A.D., Jackson; Lautrup, B.E.

    2006-01-01

    Are some ways of measuring scientific quality better than others? Sune Lehmann, Andrew D. Jackson and Benny E. Lautrup analyse the reliability of commonly used methods for comparing citation records....

  8. High-forward-bias transport mechanism in a-Si:H/c-Si heterojunction solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Schulze, T.F.; Korte, L.; Conrad, E.; Schmidt, M.; Rech, B. [Department of Silicon Photovoltaics, Helmholtz-Zentrum Berlin fuer Materialien und Energie, Kekulestrasse 5, 12489 Berlin (Germany)

    2010-03-15

    In order to elucidate the transport mechanism in a-Si:H/c-Si heterojunction solar cells under high forward bias (U > 0.5 V), we conducted temperature-dependent measurements of current-voltage (I-V) curves in the dark and under illumination. ZnO:Al/(p)a-Si:H/(n)c-Si/(n{sup +})a-Si:H cells are compared with inversely doped structures and the impact of thin undoped a-Si:H buffer layers on charge carrier transport is explored. The solar cell I-V curves are analyzed employing a generalized two-diode model which allows fitting I-V data for a broad range of samples. The fitting results are complemented with numerical simulations using AFORS-HET under consideration of microscopic a-Si:H parameters as determined by constant-final-state-yield photoelectron spectroscopy (CFSYS) to identify possible origins for a systematic increase of the high-forward-bias ideality factor along with the open-circuit voltage (V{sub oc}). It is further shown that also for a-Si:H/c-Si heterojunctions, dark I-V curve fit parameters can unequivocally be linked to V{sub oc} under illumination, which may prove helpful for device assessment. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  9. Modelling of grain boundary effects in nanocrystalline/multicrystalline silicon heterojunction solar cells

    Science.gov (United States)

    Farrokh-Baroughi, Mahdi; Sivoththaman, Siva

    2006-07-01

    Heterojunction solar cells formed by nanocrystalline silicon films on fine-grained multicrystalline silicon substrates are simulated in the presence of grain boundaries. The effects of grain boundaries on the dark and illuminated current-voltage (I-V) characteristics and spectral response (SR) of heterojunction (HJ) solar cells are assessed using 1D and 2D device simulations. The grain boundary in fine-grained multicrystalline silicon is modelled in two ways: as a defective surface with continuous defect distribution throughout the bandgap, and as a hypothetical sheet with a certain recombination velocity for electrons and holes. The SR and I-V characteristics of HJs are exploited to characterize grain boundary effects on the photovoltaic properties of the solar cells and photodetectors. Simulation results show noticeable differences on the dark I-V and SR of on- and off-grain boundary HJs. Grain boundary effects become important when fine-grained multicrystalline substrates are used. Measurement results of tiny test structures fabricated on the grain boundary show consistently inferior dark I-V and SR characteristics compared to those fabricated away from the grain and allow us to quantify the recombination at the grain boundary.

  10. Electrical properties and transport mechanisms of Au/Ba0.6Sr0.4TiO3/GaN metal-insulator-semiconductor (MIS) diode at high temperature range

    Science.gov (United States)

    Rajagopal Reddy, V.

    2016-05-01

    The electrical and transport mechanisms of a fabricated Au/Ba0.6Sr0.4TiO3 (BST)/GaN metal-insulator-semiconductor (MIS) diode have been studied in the temperature range of 280-430 K by current-voltage ( I- V) and capacitance-voltage ( C- V) measurements. The barrier heights (BHs) of the Au/BST/GaN MIS diode are found to be 0.85 eV ( I- V)/1.35 ( C- V) at 280 K and 1.14 eV ( I- V)/1.17 ( C- V) at 430 K. The series resistance ( R S) values determined by Cheung's functions are in good agreement with each other. The difference between BHs estimated by I- V and C- V methods are also discussed. Results show that the estimated interface state density ( N SS) of MIS diode decreases with an increase in temperature. Observations have indicated that the BH increases whereas ideality factor R S and N SS decreases with increasing temperature. Results have demonstrated that the reverse leakage current is dominated by Poole-Frenkel emission at temperatures of 280-340 K and by Schottky emission at temperatures of 370-430 K. It is also noted that there is a transition of the conduction mechanism in Au/BST/GaN MIS diode from Poole-Frenkel to Schottky emission at temperatures of 340-370 K.

  11. Study of highly precise outdoor characterization technique for photovoltaic modules in terms of reproducibility

    Science.gov (United States)

    Fukabori, Akihiro; Takenouchi, Takakazu; Matsuda, Youji; Tsuno, Yuki; Hishikawa, Yoshihiro

    2015-08-01

    In this study, novel outdoor measurements were conducted for highly precise characterization of photovoltaic (PV) modules by measuring current-voltage (I-V) curves with fast sweep speeds and module’s temperature, and with a PV sensor for reference. Fast sweep speeds suppressed the irradiance variation. As a result, smooth I-V curves were obtained and the PV parameter deviation was suppressed. The module’s temperature was measured by attaching resistive temperature detector sensors on the module’s backsheet. The PV sensor was measured synchronously with the PV module. The PV parameters including Isc, Pmax, Voc, and FF were estimated after correcting the I-V curves using the IEC standards. The reproducibility of Isc, Pmax, Voc, and FF relative to the outdoor fits was evaluated as 0.43, 0.58, 0.24, and 0.23%, respectively. The results demonstrate that highly precise measurements are possible using a PV measurement system with the three above-mentioned features.

  12. Time-Resolved Langmuir Probe Measurements in an Ionized PVD System

    Science.gov (United States)

    Juliano, D. R.; Hayden, D. B.; Ruzic, D. N.

    1997-10-01

    The experimental apparatus consists of a commercial-scale magnetron (Donated by Materials Research Corporation) with an RF coil between the target and substrate holder. This coil creates a secondary inductive plasma that ionizes a significant portion of the sputter flux en route from target to substrate. Ionization of the metal atoms that make up the sputter flux is highly sensitive to the high energy tail of the electron energy distribution, which in turn is highly dependent on the background gas mixture. Since there is some capacitive coupling from the coil this high energy population could change through the RF cycle. Time-averaged Langmuir probe measurements would not reveal either the extent of this high energy population or its time dependence. Further, if the probe voltage were held constant for such time-resolved measurements, they would yield incorrect results. At probe voltages above the plasma potential minimum the sheath is disrupted so that at points in the phase for which the probe voltage is below plasma potential the data is invalid. Therefore in order to take valid measurements at all phase points, it is necessary for the probe voltage to follow the RF variation in plasma potential. Using such a system, we have made time-resolved Langmuir probe measurements. Current-voltage traces as a function of phase then reveal plasma parameters as a function of time over the RF cycle for various background gases and operating parameters.

  13. Time of Flight Electrochemistry: Diffusion Coefficient Measurements Using Interdigitated Array (IDA) Electrodes

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fei; Kolesov, Grigory; Parkinson, Bruce A.

    2014-09-26

    A simple and straightforward method for measuring diffusion coefficients using interdigitated array (IDA) electrodes is reported. The method does not require that the exact electrode area be known but depends only the size of the gap between the IDA electrode pairs. Electroactive molecules produced at the generator electrode of the IDA by a voltage step or scan can diffuse to the collector electrode and the time delay before the current for the reverse electrochemical reaction is detected at the collector is used to calculate the diffusion coefficient. The measurement of the diffusion rate of Ru(NH3)6+2 in aqueous solution has been used as an example measuring diffusion coefficients using this method. Additionally, a digital simulation of the electrochemical response of the IDA electrodes was used to simulate the entire current/voltage/time behavior of the system and verify the experimentally measured diffusion coefficients. This work was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the Department of Energy, Office of Science, Office of Basic Energy Sciences.

  14. Measure for measure

    Science.gov (United States)

    Weinberger, Peter

    2012-06-01

    The present system of measures for length, weight and capacity (volume) originates from scientific ideas expressed during the French Revolution in 1789. The history of a compatible unit of length, however, turns out to be less of a scientific but rather of a political character. Here reports to the Philosophical Magazine made in the first quarter of the nineteenth century are used to trace the cultural split between meters and inches, and between kilograms and pounds, that can be experienced in many parts of the world.

  15. A gated four probe technique for field effect measurements on disordered organic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hauff, E. von; Spethmann, N.; Parisi, J. [Carl von Ossietzky Univ. of Oldenburg (Germany). Dept. for Energy and Semiconductor Research

    2008-09-15

    A gated four probe measurement technique to isolate contact resistances in field effect measurements on disordered organic semiconductors was investigated. Organic field effect transistors (OFETs) were prepared with two additional electrodes in the contact geometry protruding into the source-drain channel to monitor the variation in potential across the channel. Two high impedance electrometers were used to determine the potential at the contacts. This technique allows to directly determine the magnitude of the parasitic contact resistances between metal contact and organic semiconductor from the drop in potential at the contact regions. The effects of contact resistances, which can falsify measurements on bulk transport parameters such as the field effect mobility, can be then eliminated during material characterization. Additionally, the temperature and electric field dependence of the contact resistances offers valuable information about the charge injection and extraction processes between metal and organic semiconductor. The effects of the four probe geometry, specifically the effect of the channel electrodes on the current-voltage characteristics, of hole transport in a polythiophene (P3HT) OFET with Au contacts were investigated and found not to influence device performance, except at currents <<1 nA. The IV characteristics were shown to follow the expected FET behaviour. From the variation in potential along the channel it was found that contact resistances at the source contact (charge injecting contact) are minimal while contact resistances at the drain contact (charge extracting contact) are significant, resulting in a much lower effective source-drain voltage than that applied to the device. (orig.)

  16. 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.

  17. Noninvasive xenon-133 measurements of cerebral blood flow using stationary detectors compared with dynamic emission tomography

    DEFF Research Database (Denmark)

    Schroeder, T; Vorstrup, S; Lassen, N A;

    1986-01-01

    Repeated bedside measurements of CBF have been made possible by the recent development of a mobile unit with 10 stationary detectors using the intravenous xenon-133 method. To evaluate this technique, comparative CBF studies at rest and following the application of a cerebral vasodilatory stimulus...... (acetazolamide, 1 g i.v.) were performed with the mobile equipment and with xenon-133 single-photon emission inhalation tomography in patients with cerebrovascular disease. The CBF level and the flow response to acetazolamide as determined with the two methods were well correlated, although at low flow levels...

  18. Simulation and measurement of a Ka-band HTS MMIC Josephson junction mixer

    Science.gov (United States)

    Zhang, Ting; Pegrum, Colin; Du, Jia; Guo, Yingjie Jay

    2017-01-01

    We report modeling and simulation results for a Ka band high-temperature superconducting (HTS) monolithic microwave integrated circuit (MMIC) Josephson junction mixer. A Verilog-A model of a Josephson junction is established and imported into the system simulator to realize a full HTS MMIC circuit simulation containing the HTS passive circuit models. Impedance matching optimization between the junction and passive devices is investigated. Junction DC I-V characteristics, current and local oscillator bias conditions and mixing performance are simulated and compared with the experimental results. Good agreement is obtained between the simulation and measurement results.

  19. Gallium Nitride Electrical Characteristics Extraction and Uniformity Sorting

    Directory of Open Access Journals (Sweden)

    Shyr-Long Jeng

    2015-01-01

    Full Text Available This study examined the output electrical characteristics—current-voltage (I-V output, threshold voltage, and parasitic capacitance—of novel gallium nitride (GaN power transistors. Experimental measurements revealed that both enhanced- and depletion-mode GaN field-effect transistors (FETs containing different components of identical specifications yielded varied turn-off impedance; hence, the FET quality was inconsistent. Establishing standardized electrical measurements can provide necessary information for designers, and measuring transistor electrical characteristics establishes its equivalent-circuit model for circuit simulations. Moreover, high power output requires multiple parallel power transistors, and sorting the difference between similar electrical characteristics is critical in a power system. An isolated gate driver detection method is proposed for sorting the uniformity from the option of the turn-off characteristic. In addition, an equivalent-circuit model for GaN FETs is established on the basis of the measured electrical characteristics and verified experimentally.

  20. Measurement of H{sup -} ion density in a multicusp ion source by a dc-laser-photodetachment-method

    Energy Technology Data Exchange (ETDEWEB)

    Nishiura, Masaki; Yokoyama, Mitsuru; Kasuya, Toshirou; Wada, Motoi [Doshisha Univ., Kyoto (Japan). Faculty of Engineering

    1995-08-01

    When the Langmuir probe immersed in a hydrogen plasma was irradiated with an Ar{sup +} laser beam, the electron saturation current showed an increment corresponding with the density of negative hydrogen ions (H{sup -}). The measured photodetachment signal was quite small compared with the probe current. Consequently, the measured value of the photodetachment current should include the first derivative component of the probe I-V characteristic. A correction for this component has been made to determine the true photodetachment current. After the correction, the ratio of hydrogen negative ion density to electron density was calculated to be about 41%. (author).

  1. 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.

  2. Two Dimensional LIF Measurements and Potential Structure of Ion Beam Formation in an Argon Helicon Plasma

    Science.gov (United States)

    Aguirre, Evan; Scime, Earl; Good, Timothy

    2016-10-01

    We report 2-dimensional, spatially resolved observations of ion beam formation in an expanding helicon plasma. Previous studies found that a current free double layer (CFDL) spontaneously arises at low pressure, below 1 mT. We use Laser Induced Fluorescence (LIF), a non-perturbative diagnostic to measure the ion velocity distribution functions (IVDFs) of argon ions both parallel and perpendicular to the background magnetic field. We report ion beam formation as a function of the expansion chamber magnetic field (0-108 G). The ion beam appears peaked in the center of the expansion chamber and decays over a few centimeters radially. We also report the potential structure of the plasma obtained with a planar Langmuir probe. To obtain meaningful Langmuir probe measurements, averages of tens of current-voltage are needed to reduce the effects of large electrostatic fluctuations that arise in plasmas that generate ion beams. We report the dependence of density, electron temperature, and floating potential on radial and axial position in the expansion plume. NSF Award PHYS-1360278.

  3. A functional material based photodiode for solar tracking systems

    Science.gov (United States)

    Dere, A.; Tataroğlu, A.; Al-Sehemi, Abdullah G.; Al-Ghamdi, Ahmed A.; El-Tantawy, F. Farid; Farooq, W. A.; Yakuphanoglu, F.

    2017-09-01

    To prepare phosphotungstic acid (PTA) thin film was used drop-coating method. The film was dropped on p-Si having ohmic contact. The electrical and photovoltaic properties the fabricated Al/p-Si/phospotungstic acid(PTA)/Al photodiode were investigated. The current-voltage (I-V) measurements were carried out under dark and various illumination intensities. Under illumination, the photocurrent of the photodiode was found to be higher than the dark current. The prepared photodiode exhibited photovoltaic behavior. Also, the transient photocurrent measurement confirms that the photocurrent is sensitive to the illumination intensities. In addition, the capacitance/conductance-voltage (C/G-V) measurements were studied in the frequency range of 10 kHz to 1 MHz. The capacitance decreases with increasing frequency, suggesting a continuous distribution of interface states. As result, the prepared photodiode can be used in optoelectronic device applications.

  4. Electrical and photoelectrical characteristic investigation of a new generation photodiode based on bromothymol blue dye

    Science.gov (United States)

    Gencer Imer, A.; Tombak, A.; Korkut, A.

    2016-04-01

    Bromothymol blue (BTB) with the molecular formula of C27H28Br2O5S 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 & photoelectrical parameters of diode can be changed, and also the performance of the device could be affected by the organic thin film interlayer.

  5. 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.

  6. A physical model for the reverse leakage current in (In,Ga)N/GaN light-emitting diodes based on nanowires

    Science.gov (United States)

    Musolino, M.; van Treeck, D.; Tahraoui, A.; Scarparo, L.; De Santi, C.; Meneghini, M.; Zanoni, E.; Geelhaar, L.; Riechert, H.

    2016-01-01

    We investigated the origin of the high reverse leakage current in light emitting diodes (LEDs) based on (In,Ga)N/GaN nanowire (NW) ensembles grown by molecular beam epitaxy on Si substrates. To this end, capacitance deep level transient spectroscopy (DLTS) and temperature-dependent current-voltage (I-V) measurements were performed on a fully processed NW-LED. The DLTS measurements reveal the presence of two distinct electron traps with high concentrations in the depletion region of the p-i-n junction. These band gap states are located at energies of 570 ± 20 and 840 ± 30 meV below the conduction band minimum. The physical origin of these deep level states is discussed. The temperature-dependent I-V characteristics, acquired between 83 and 403 K, show that different conduction mechanisms cause the observed leakage current. On the basis of all these results, we developed a quantitative physical model for charge transport in the reverse bias regime. By taking into account the mutual interaction of variable range hopping and electron emission from Coulombic trap states, with the latter being described by phonon-assisted tunnelling and the Poole-Frenkel effect, we can model the experimental I-V curves in the entire range of temperatures with a consistent set of parameters. Our model should be applicable to planar GaN-based LEDs as well. Furthermore, possible approaches to decrease the leakage current in NW-LEDs are proposed.

  7. Measurement of solar wind electron density and temperature in the shocked region of Venus and the density and temperature of photoelectrons within the ionosphere of Venus

    Science.gov (United States)

    Knudsen, William C.; Jones, Douglas E.; Peterson, Bryan G.; Knadler, Charles E.

    2016-08-01

    Presented herein are measurements of the solar wind electron number density and temperature near and within the bow shock of Venus. The measurements were made by the Pioneer Venus mission Orbiter Retarding Potential Analyzer operating in its suprathermal electron mode. The measurements are essentially point measurements. The spacecraft travels approximately 0.8 km during the 0.1 s time interval required to record a single I-V curve. The dual measurement of a density and temperature is obtained from one sweep by least squares fitting a mathematical Maxwellian expression to the I-V curve. The distance between successive measurements is approximately 100 km. In many orbits, when the spacecraft is crossing or traveling within the bow shock, the derived densities and temperatures (high density, high temperature (HDHT)) are large, densities of the order of 100 cm-3 and temperatures of the order of several hundred eV. We interpret these HDHT measurements as measurements in regions where the large, directed kinetic energy of the solar wind ions is being degraded into randomized, more thermal-like energy distributions of the electrons and ions through wave-particle interactions. The HDHT values define the electron energy distribution in the limited energy interval 0 to 50 eV. We assume that the underlying electron flux distributions are flat topped like those measured in the Earth's bow shock. We also report densities and temperatures of EUV produced photoelectron energy distributions measured within the ionosphere.

  8. The Annealing Effects of ZnO Thin Films on Characteristic Parameters of Au/ZnO Schottky Contacts on n-Si

    Directory of Open Access Journals (Sweden)

    A. Toprak

    2012-03-01

    Full Text Available 200 nm ZnO thin films have been grown on n type Silicon substrates by DC sputtering technique. One of the thin films has been annealed at 300 ºC for 45 minutes. The Au front contacts on ZnO thin films have been formed by evaporation of Au metal by means of shadow mask. It has been seen that the rectification ratio of Au/ZnO device obtained using annealed ZnO thin film is higher than the one obtained using unannealed ZnO thin film. The characteristic parameters of Au/ZnO junctions such as ideality factor, barrier height and series resistance obtained by current-voltage (I-V measurements of the structures at room temperature and in dark have been compared with each others. 200 nm ZnO thin films have been grown on n type Silicon substrates by DC sputtering technique. One of the thin films has been annealed at 300 ºC for 45 minutes. The Au front contacts on ZnO thin films have been formed by evaporation of Au metal by means of shadow mask. It has been seen that the rectification ratio of Au/ZnO device obtained using annealed ZnO thin film is higher than the one obtained using unannealed ZnO thin film. The characteristic parameters of Au/ZnO junctions such as ideality factor, barrier height and series resistance obtained by current-voltage (I-V measurements of the structures at room temperature and in dark have been compared with each others. 200 nm ZnO thin films have been grown on n type Silicon substrates by DC sputtering technique. One of the thin films has been annealed at 300 ºC for 45 minutes. The Au front contacts on ZnO thin films have been formed by evaporation of Au metal by means of shadow mask. It has been seen that the rectification ratio of Au/ZnO device obtained using annealed ZnO thin film is higher than the one obtained using unannealed ZnO thin film. The characteristic parameters of Au/ZnO junctions such as ideality factor, barrier height and series resistance obtained by current-voltage (I-V measurements of the structures at

  9. s Measurements

    Indian Academy of Sciences (India)

    Sunanda Banerjee

    2003-11-01

    The strong coupling constant, s, has been determined from many pure inclusive and semi-inclusive measurements. All these measurements, measured at different scales, are consistent among each other and the measurements can be combined to give s()=0.118 ± 0.003.

  10. Measuring Savings

    OpenAIRE

    Mark Schreiner

    2001-01-01

    Development depends on saving. But what exactly is saving, and how is it measured? This paper defines saving and describes several measures of financial savings. The measures account for the passage of time and for the three stages of saving: putting in (depositing), keeping in (maintaining a balance), and taking out (withdrawing). Together, the different measures capture how people move financial resources through time.

  11. 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.

  12. A technique for conditioning and calibrating force-sensing resistors for repeatable and reliable measurement of compressive force.

    Science.gov (United States)

    Hall, Rick S; Desmoulin, Geoffrey T; Milner, Theodore E

    2008-12-01

    Miniature sensors that could measure forces applied by the fingers and hand without interfering with manual dexterity or range of motion would have considerable practical value in ergonomics and rehabilitation. In this study, techniques have been developed to use inexpensive pressure-sensing resistors (FSRs) to accurately measure compression force. The FSRs are converted from pressure-sensing to force-sensing devices. The effects of nonlinear response properties and dependence on loading history are compensated by signal conditioning and calibration. A fourth-order polynomial relating the applied force to the current voltage output and a linearly weighted sum of prior outputs corrects for sensor hysteresis and drift. It was found that prolonged (>20h) shear force loading caused sensor gain to change by approximately 100%. Shear loading also had the effect of eliminating shear force effects on sensor output, albeit only in the direction of shear loading. By applying prolonged shear loading in two orthogonal directions, the sensors were converted into pure compression sensors. Such preloading of the sensor is, therefore, required prior to calibration. The error in compression force after prolonged shear loading and calibration was consistently industrial design applications where measurements of finger and hand force are needed.

  13. Automatic measurements of plasma parameters in the PUPR mirror and cusp plasma machine

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, S; Colmenares, F; Gonzalez-Lizardo, A; Leal-Quiros, E [Plasma Engineering Laboratory, Polytechnic University of Puerto Rico, San Juan, PR 00918 (Puerto Rico)

    2008-10-15

    This paper presents an ongoing effort to develop an automatic measurement system for plasma diagnostics at the Plasma Engineering Laboratory of the Polytechnic University of Puerto Rico (PUPR), along with an example of its operation. The system is intended to be used with electrostatic probes such as single and double Langmuir probes, emissive probes, ion and electron energy analyzers, etc. The automatic measurement system includes automatic positioning of the probes inside the plasma chamber, automatic voltage sweep of the probes for each position, and automatic analysis of the probe I-V characteristic. The results of measurements obtained by using this automatic measurement system during a particular experiment are shown and compared with a traditional method with satisfactory results.

  14. Damage Induced by Neutron Radiation on Output Characteristics of Solar Cells, Photodiodes, and Phototransistors

    Directory of Open Access Journals (Sweden)

    Biljana Simić

    2013-01-01

    Full Text Available This study investigates the effects of neutron radiation on I-V characteristics (current dependance on voltage of commercial optoelectronic devices (silicon photodiodes, phototransistors, and solar panels. Current-voltage characteristics of the samples were measured at room temperature before and after irradiation. The diodes were irradiated using Am-Be neutron source with neutron emission of 2.7×106 n/s. The results showed a decrease in photocurrent for all samples which could be due to the existence of neutron-induced displacement defects introduced into the semiconductor lattice. The process of annealing has also been observed. A comparative analysis of measurement results has been performed in order to determine the reliability of optoelectronic devices in radiation environments.

  15. Charge trapping and de-trapping in Si-nanoparticles embedded in silicon oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Morales-Sanchez, A.; Barreto, J.; Dominguez, C. [IMB-CNM (CSIC), Campus UAB, 08193 Bellaterra, Barcelona (Spain); Aceves, M.; Yu, Z. [INAOE, Electronics Department, Puebla, Pue., 72000 (Mexico); Luna, J.A. [CCMC, UNAM, Optics Department, Ensenada, BC, 22800 (Mexico)

    2008-07-01

    Electrical properties of silicon nanoparticles (Si-np's) embedded in a silicon oxide matrix were studied using MOS-like structures. Si-np's were created after silicon rich oxide (SRO) films were thermally annealed at 1100 C. Capacitance-voltage (C-V) characteristics showed downward and upward peaks in the accumulation region. Current-voltage (I-V) measurements exhibited current valleys and downward and upward peaks. Current versus time (I-t) measurements were also done at a negative constant gate voltage. A switching behaviour between two current states (ON and OFF) was observed. These effects have been related to the charge trapping and de-trapping of the Si-np's embedded in the SRO films. (copyright 2008 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. 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.)

  17. 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...... duration and cost, avoids stress transients while ramping to and from the stress temperature, eliminates flash testing except at the initial and final data points, and enables significantly faster and more detailed acquisition of statistical data for future application of various statistical reliability...... on several crystalline silicon module designs to determine the extent to which the temperature dependency of maximum power is affected by the degradation of the modules. The results using the superposition principle show a mismatch between the power degradation measured at stress temperature and the power...

  18. Chemiresistive sensor based on polythiophene-modified single-walled carbon nanotubes for detection of NO2

    Science.gov (United States)

    Gaikwad, Sumedh; Bodkhe, Gajanan; Deshmukh, Megha; Patil, Harshada; Rushi, Arti; Shirsat, Mahendra D.; Koinkar, Pankaj; Kim, Yun-Hae; Mulchandani, Ashok

    2015-03-01

    In the present investigation, a chemiresistive sensor based on conducting polythiophene-modified single-walled carbon nanotubes (SWNTs) for NO2 detection has been reported. The SWNTs were aligned across 3 μm gap between two gold microelectrodes on Si/SiO2 substrate. Alignment of SWNTs was carried out by using AC dielectrophoretic technique and it was confirmed by current-voltage (I-V) measurement. Aligned SWNTs were modified by conducting polythiophene using charge controlled potentiostatic deposition and it was confirmed by field-effect transistor (FET) and electrochemical measurements. Polythiophene-modified SWNT devices were used for the NO2 detection in chemiresistive modality. This sensor exhibited very good linear response range from 10 ppb to 10 ppm.

  19. Magnetization of Multifilamentary Superconductor Nb3Sn in Perpendicular Field

    Institute of Scientific and Technical Information of China (English)

    LIU Fang; WENG Peide; WU Yu; LONG Feng

    2008-01-01

    Hysteresis loss is one of the electromagnetic characteristics controlled by time evo-lution of magnetic field and current distribution inside the conductor. Brandt's method allows us to model the interaction of the conductor with an external magnetic field. Instead of the constant critical current density (Jc =CONST), the Jc scaling law from current-voltage (I-V) measurement is used to model the magnetization loop. By comparing the calculated results with the measured data, it is shown that the Jc scaling law, i.e. the deviatoric strain model, is not useful in a very low field. To solve this problem, the Kim model about Jc as a function of applied field has been applied in the low field case. This method can be used to predict the hysteresis loss of Nb3Sn filamentary strand.

  20. Characterization of deposited CdS thin films by Spray Pyrolysis method and used in Cd/CdS/p-Si/Al structure

    Science.gov (United States)

    Özakın, Oǧuzhan; Aktaş, Şeydanur; Güzeldir, Betül; Saǧlam, Mustafa

    2017-04-01

    In our study, as p-type crystalline Si substrate was used. Omic contact was performed by evaporating Al metal on the matt surface of crystal. On the other surface of it CdS thin film were enlarged with the technique of Spray Pyrolysis. Structural characteristics of the grown thin film was examined SEM and EDAX image. When examining SEM image of CdS thin film were totally covered the p-Si crystal surface of it was nearly homogeneous and The EDAX spectra showed that the expected different ratios metal percent exist in the alloys, approximately. On the CdS films whose surface features were investigated, at 10-7 torr pressure was obtained Cd/CdS/p-Si/Al sandwich structure by evaporating Cd. Firstly, the I-V (current-voltage) characteristics on 80K between 320K at room temperature of this structure was measured. I-V characteristics of the examined at parameters diodes calculation, Thermionic Emission, were used. The characteristic parameters such as barrier height and ideality factor of this structure have been calculated from the forward bias I-V characteristics. Consequently, it was seen that CdS thin film grown on p-Si semiconductor will be used confidently in Cd/p-Si metal-semiconductor contacts thanks to Spray Pyrolysis method.

  1. Carrier-transport studies of III-nitride/Si{sub 3}N{sub 4}/Si isotype heterojunctions

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Mahesh; Roul, Basanta [Materials Research Center, Indian Institute of Science, Bangalore-560012 (India); Central Research Laboratory, Bharat Electronics, Bangalore-560013 (India); Bhat, Thirumaleshwara N.; Rajpalke, Mohana K.; Krupanidhi, S.B. [Materials Research Center, Indian Institute of Science, Bangalore-560012 (India); Kalghatgi, A.T. [Central Research Laboratory, Bharat Electronics, Bangalore-560013 (India)

    2012-05-15

    GaN/Si{sub 3}N{sub 4}/n-Si and InN/Si{sub 3}N{sub 4}/n-Si heterojunctions (HJs) were fabricated using plasma-assisted molecular beam epitaxy for a comparison study. Single-crystalline wurtzite structures of GaN and InN epilayers were confirmed by high-resolution X-ray diffraction and thickness of ultrathin Si{sub 3}N{sub 4} layer was measured by transmission electron microscopy. n-GaN/Si{sub 3}N{sub 4}/n-Si HJs show diode-like rectifying current-voltage (I-V) characteristic, while n-InN/Si{sub 3}N{sub 4}/n-Si HJs show symmetric nonlinear I-V behavior. The I-V characteristics of both HJs were discussed in terms of the band diagram of HJs and the carrier transport mechanism. The activation energies of carrier conduction were estimated to be {proportional_to}29 meV for GaN/Si{sub 3}N{sub 4}/Si and {proportional_to}95 meV for InN/Si{sub 3}N{sub 4}/Si HJs. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  2. 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.

  3. 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.

  4. Measuring Happiness

    OpenAIRE

    Richter, Luise; Unger, Cindie

    2015-01-01

    The project at hand aims at outlining if and how happiness measurements can constitute an alternative to the neoliberal measurements of prosperity dominating today. For this purpose, four cases, namely the UN 2013 World Happiness Report and the OECD 2013 Guidelines on measuring subjective well-being as one entity, the Happy Planet Index 2012 from the New Economics Foundation and the report on the Bhutanese Gross National Happiness measurements (2012), have been selected. These perspectives, w...

  5. Measure Lines

    Science.gov (United States)

    Crissman, Sally

    2011-01-01

    One tool for enhancing students' work with data in the science classroom is the measure line. As a coteacher and curriculum developer for The Inquiry Project, the author has seen how measure lines--a number line in which the numbers refer to units of measure--help students not only represent data but also analyze it in ways that generate…

  6. Water Dissociation Phenomena on a Bipolar Membrane——Current-voltage Curve in Relation with Ionic Transport and Limiting Current Density

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The water dissociation mechanism on a bipolar membrane under the electrical field was investigated and characterized in terms of ionic transport and limiting current density. It is considered that the depletion layer exists at the junction of a bipolar membrane, which is coincided with the viewpoint of the most literatures, but we also consider that the thickness and conductivity of this layer is not only related with the increase of the applied voltage but also with the limiting current density. Below the limiting current density, the thickness of the depletion layer keeps a constant and the conductivity decreases with the increase of the applied voltage;while above the limiting current density, the depletion thickness will increase with the increase of the applied voltage and the conductivity keeps a very low constant. Based on the data reported in the literatures and independent determinations, the limiting current density was calculated and the experimental curves Ⅰ- Ⅴ in the two directions were compared with the theoretical calculations. It is demonstrated that above the limiting current density, the experimental results,either in the L-H direction or in the H-L direction, are consistent with the theoretical calculations; below the limiting current density, a slight deviation exists between the experimental and the theoretical results, and between the experimental results in the two directions. The change in Donnan potential due to the asymmetry of the mono-layers and the changes of ionic composition in the two directions is possibly responsible for this deviation.

  7. 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…

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

    OpenAIRE

    Ricardo Vera; Juan Carlos Salcedo-Reyes; Juan Pablo Cuéllar-Alvarado; Diana Rocío Pardo-Pardo; Henry Alberto Méndez-Pinzón; Beynor Antonio Páez-Sierra

    2010-01-01

    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 us...

  9. 有机薄膜晶体管直流电流-电压模型研究%Study of DC Current-Voltage Model for OTFT

    Institute of Scientific and Technical Information of China (English)

    张玲珑; 滕支刚; 钟传杰

    2014-01-01

    针对有机薄膜晶体管(OTFT)表面势对源漏电流的影响,提出一个有机薄膜晶体管的直流电流-电压模型.该模型应用Lambert W函数和Poole-Frenkel迁移率理论,定量地描述了表面势对源漏电流的影响.计算结果表明,低和高电压工作的OTFT计算值与实验值均有良好的一致性.

  10. Comment on ``Monte Carlo investigation of current voltage and avalanche noise in GaN double-drift impact diodes'' [J. Appl. Phys. 97, 043709 (2005)

    Science.gov (United States)

    Dash, G. N.

    2005-11-01

    The avalanche noise behavior of impact avalanche transit-time (IMPATT) diodes has been modeled by Reklaitis and Reggiani [J. Appl. Phys. 97, 043709 (2005)]. They have obtained general agreement of their results with those of McIntyre [IEEE Trans. Electron Devices ED-13, 164 (1966)]. However, McIntyre's theory predicts the opposite noise behavior from that observed in the IMPATT diode. Hence the applicability of the noise model of Reklaitis and Reggiani to IMPATT diode is questionable.

  11. 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

  12. 基于 LabVIEW 串口通信的太阳能电池I-V 曲线测试系统的设计与应用%Design and implementation of voltage-current testing system based on LabVIEW with serial communication

    Institute of Scientific and Technical Information of China (English)

    秦中立; 范望喜; 张秀花

    2013-01-01

      采用LabVIEW软件平台搭建一套自动化I-V曲线测试系统,系统的数据采集部分由LabVIEW 8.5软件、VISA4.1库、Keithley 2000数字源表、低压电源和计算机等软、硬件所组成.对结构为ITO/PEDOT :PSS/P3HT :PCBM/Al的有机太阳能电池进行的I-V曲线测试,开路电压为0.608 V ,短路电流为8.25 mA/cm2,填充因子为0.662,电池的转换效率为3.32%,其结果与CHI660电化学测量系统测量的结果相近,表明此系统具有可靠性、实时性和准确性等特点.%A auto-testing system based on LabVIEW was designed for voltage-current characteristics ,which was based on LabVIEW 8 .5 express ,Visa 4 .1 , Keithley 2000 ,low-voltage power supply and computer .It was applied to test the voltage-current characteristics of organic solar cells with the structure of ITO/PEDOT :PSS/P3HT :PCBM/Al , and its open circuit viltage was 0 .608 V ,short circuit current was 8 .25 mA・cm -2 ,fill factor was 0 .662 ,energy conversion efficiecy was 3 .32% ,which was as much as the results measured by the CHI660 electrochemical measurement system .It was showed the system had reliable ,real-timed and aecurate properties .

  13. 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

    2013-02-08

    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.

  14. 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....

  15. Dependence of Characteristic Diode Parameters in Ni/n-GaAs Contacts on Thermal Annealing and Sample Temperature

    Science.gov (United States)

    Yildirim, N.; Dogan, H.; Korkut, H.; Turut, A.

    We have prepared the sputtered Ni/n-GaAs Schottky diodes which consist of as-deposited, and diodes annealed at 200 and 400°C for 2 min. The effect of thermal annealing on the temperature-dependent current-voltage (I-V) characteristics of the diodes has been experimentally investigated. Their I-V characteristics have been measured in the temperature range of 60-320 K with steps of 20 K. It has been seen that the barrier height (BH) slightly increased from 0.84 (as-deposited sample) to 0.88 eV at 300 K when the contact has been annealed at 400°C. The SBH increased whereas the ideality factor decreased with increasing annealing temperature for each sample temperature. The I-V measurements showed a dependence of ideality factor n and BH on the measuring temperature that cannot be explained by the classical thermionic emission theory. The experimental data are consistent with the presence of an inhomogeneity of the SBHs. Therefore, the temperature dependent I-V characteristics of the diodes have been discussed in terms of the multi-Gaussian distribution model. The experimental data good have agree with the fitting curves over whole measurement temperature range indicating that the SBH inhomogeneity of our as-deposited and annealed Ni/n-GaAs SBDs can be well-described by a double-Gaussian distribution. The slope of the nT versus T plot for the samples has approached to unity with increasing annealing temperature and becomes parallel to that of the ideal Schottky contact behavior for the 400°C annealed diode. Thus, it has been concluded that the thermal annealing process translates the metal-semiconductor contacts into thermally stable Schottky contacts.

  16. 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.)

  17. Investigation of high-temperature charge transport mechanism in Al-Gd2O3-Al-based metal-insulator-metal (MIM) structure

    Science.gov (United States)

    Wasiq, M. F.; Mahmood, Khalid; Aen, Faiza; Warsi, Muhammad Farooq; Khan, Muhammad Azhar

    2016-12-01

    In this paper, the charge conduction mechanism at high temperature in Al-Gd2O3 (MIM) structure has been investigated by performing temperature-dependent current-voltage measurements in the temperature range 280-390 K. MIM structure is realized by electron beam evaporation system where thin films of Gd2O3 (40, 60 and 80 nm) and Al metal on both sides of dielectric film were deposited on glass substrate. The possibility of different transport mechanisms has been testified by plotting various graphs. The nonlinear behavior of Ln V versus Ln I and V 1/2 versus Ln V/ I graphs ruled out the possibility of space-charge-limited conduction (SCLC) and Poole-Frenkel mechanism in Al-Gd2O3-Al MIM structure. The straight lines Ln I- V 1/2 graphs at various temperatures confirmed that Schottky emission is the dominant transport mechanism in Al-Gd2O3-Al structure. The calculated values of field barrier lowering coefficient at different measurement temperatures were in good agreement with the theoretical prediction confirming conduction is via Schottky emission. The field-dependent Ln( I/ T 2) versus 1000/ T plots were obeyed a linear relationship according to Schottky emission theory. Furthermore, the dielectric thickness dependence room-temperature current-voltage characteristics of Al-Gd2O3-Al MIM structure were showed strong dependence of current on dielectric film thickness according to Schottky emission theory of conduction current.

  18. Field Measurements

    CERN Document Server

    Bottura, L

    2004-01-01

    The measurement of the magnetic field is often the final verification of the complex design and fabrication process of a magnetic system. In several cases, when seeking high accuracy, the measurement technique and its realization can result in a considerable effort. This note describes most used measurement techniques, such as nuclear magnetic resonance, fluxmeters and Hall generators, and their typical range of application. In addition some of less commonly used techniques, such as magneto-optical, SQUIDs, or particle beams methods, are listed.

  19. 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...

  20. Photovoltaic Effects and Charge Transport Studies in Phycobiliproteins

    Science.gov (United States)

    1993-06-30

    phycobilins are shown in Figure 1. Phycoerythrin (PE). phycocyanin (PC) and allophycocyanin (APC) are the individual biliproteins that self-assemble to form... phycocyanin and (b) phycocrythrin. thin films. The dark current-voltage (I-V) characteristics of ihc Au-proicin-Au samples were determined prior to optical