WorldWideScience

Sample records for single semiconductor switch

  1. Compound semiconductor optical waveguide switch

    Science.gov (United States)

    Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

    2003-06-10

    An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

  2. Single frequency semiconductor lasers

    CERN Document Server

    Fang, Zujie; Chen, Gaoting; Qu, Ronghui

    2017-01-01

    This book systematically introduces the single frequency semiconductor laser, which is widely used in many vital advanced technologies, such as the laser cooling of atoms and atomic clock, high-precision measurements and spectroscopy, coherent optical communications, and advanced optical sensors. It presents both the fundamentals and characteristics of semiconductor lasers, including basic F-P structure and monolithic integrated structures; interprets laser noises and their measurements; and explains mechanisms and technologies relating to the main aspects of single frequency lasers, including external cavity lasers, frequency stabilization technologies, frequency sweeping, optical phase locked loops, and so on. It paints a clear, physical picture of related technologies and reviews new developments in the field as well. It will be a useful reference to graduate students, researchers, and engineers in the field.

  3. A Component-Minimized Single-Phase Active Power Decoupling Circuit with Reduced Current Stress to Semiconductor Switches

    DEFF Research Database (Denmark)

    Tang, Yi; Blaabjerg, Frede

    2015-01-01

    inductor. With such a configuration, this leg can control the current going into the two output capacitors connected in series for power decoupling, and the other leg can control the line current according to active and reactive power requirement. The proposed topology does not require additional passive...... component, e.g. inductors or film capacitors for ripple energy storage because this task can be accomplished by the dc-link capacitors, and therefore its implementation cost can be minimized. Another unique feature of the proposed topology is that the current stress of power semiconductors can be reduced...

  4. CO2 laser pulse switching by optically excited semiconductors

    International Nuclear Information System (INIS)

    Silva, V.L. da.

    1986-01-01

    The construction and the study of a semi-conductor optical switch used for generating short infrared pulses and to analyse the semiconductor characteristics, are presented. The switch response time depends on semiconductor and control laser characteristics. The results obtained using a Ge switch controlled by N 2 , NdYag and Dye lasers are presented. The response time was 50 ns limited by Ge recombination time. The reflectivity increased from 7% to 59% using N 2 laser to control the switch. A simple model for semiconductor optical properties that explain very well the experimental results, is also presented. (author) [pt

  5. Single filament semiconductor laser

    International Nuclear Information System (INIS)

    Botez, D.

    1980-01-01

    A semiconductor laser comprising: a body of semiconductor material including a substrate having a surface and a pair of spaced, substantially parallel dove-tailed shaped grooves in said surface, said body having a pair of end surfaces between which said grooves extend, said end surfaces being reflective to light with at least one of said end surfaces being partially transparent to light a first epitaxial layer over said surface of the substrate and the surfaces of the grooves, said first epitaxial layer having a flat surface portion over the portion of the substrate surface between the grooves, a thin second epitaxial layer over said first epitaxial layer, a third epitaxial layer over said second epitaxial layer, said first and third epitaxial layers being of opposite conductivity types and the second epitaxial layer being the active recombination region of the laser with the light being generated therein in the vicinity of the portion which is over the flat surface portion of the first epitaxial layer, and a pair of contacts on said body with one contact being over said third epitaxial body and the other being on said substrate

  6. Transistor electronics use of semiconductor components in switching operations

    CERN Document Server

    Rumpf, Karl-Heinz

    2014-01-01

    Transistor Electronics: Use of Semiconductor Components in Switching Operations presents the semiconductor components as well as their elementary circuits. This book discusses the scope of application of electronic devices to increase productivity. Organized into eight chapters, this book begins with an overview of the general equation for the representation of integer positive numbers. This text then examines the properties and characteristics of basic electronic components, which relates to an understanding of the operation of semiconductors. Other chapters consider the electronic circuit ar

  7. Neutron and gamma irradiation effects on power semiconductor switches

    Science.gov (United States)

    Schwarze, G. E.; Frasca, A. J.

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN Bipolar Junction Transistors (BJTs), and Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs). BJTs show a rapid decrease in gain, blocking voltage, and storage time for neutron irradiation, and MOSFETs show a rapid decrease in the gate threshold voltage for gamma irradiation.

  8. Neutron and gamma irradiation effects on power semiconductor switches

    International Nuclear Information System (INIS)

    Schwarze, G.E.; Frasca, A.J.

    1990-01-01

    The performance characteristics of high power semiconductor switches subjected to high levels of neutron fluence and gamma dose must be known by the designer of the power conditioning, control and transmission subsystem of space nuclear power systems. Location and the allowable shielding mass budget will determine the level of radiation tolerance required by the switches to meet performance and reliability requirements. Neutron and gamma ray interactions with semiconductor materials and how these interactions affect the electrical and switching characteristics of solid state power switches is discussed. The experimental measurement system and radiation facilities are described. Experimental data showing the effects of neutron and gamma irradiation on the performance characteristics are given for power-type NPN bipolar junction transistors (BJTs), and metal-oxide-semiconductor field effect transistors (MOSFETs)

  9. Experimental study on the characteristics of semiconductor opening switch

    CERN Document Server

    Su Jian Cang; Ding Yong Zhong; Song Zhi Min; Ding Zhen Jie; Liu Guo Zhi

    2002-01-01

    An experimental set-up is developed to measure the characteristics of semiconductor opening switch (SOS). The parameters, such as interruption impedance, current int eruption time, voltage gain, pulse duration and energy transfer efficiency, are studied experimentally. The experimental results show that forward pumping time and reverse pumping time are important parameters for semiconductor opening switches. The influences of forward pumping time and reverse pumping time on interruption time, voltage gain, and energy transfer efficiency are obtained. In the interruption process, the impedance variation is divided into three phases: that is rapid increasing phase, slow change phase and completely interruption phase

  10. Current measurement method for characterization of fast switching power semiconductors with Silicon Steel Current Transformer

    DEFF Research Database (Denmark)

    Li, Helong; Beczkowski, Szymon; Munk-Nielsen, Stig

    2015-01-01

    This paper proposes a novel current measurement method with Silicon Steel Current Transformer (SSCT) for the characterization of fast switching power semiconductors. First, the existing current sensors for characterization of fast switching power semiconductors are experimentally evaluated...

  11. High-power semiconductor RSD-based switch

    Energy Technology Data Exchange (ETDEWEB)

    Bezuglov, V G; Galakhov, I V; Grusin, I A [All-Russian Scientific Research Inst. of Experimental Physics, Sarov (Russian Federation); and others

    1997-12-31

    The operating principle and test results of a high-power semiconductor RSD-based switch with the following operating parameters is described: operating voltage 25 kV, peak operating current 200 kA, maximum transferred charge 70 C. The switch is intended for use by high-power capacitor banks of state-of-the-art research facilities. The switch was evaluated for applicability in commercial pulsed systems. The possibility of increasing the peak operating current to 500 kA is demonstrated. (author). 4 figs., 2 refs.

  12. High power semiconductor switching in the nanosecond regime

    International Nuclear Information System (INIS)

    Zucker, O.S.; Long, J.R.; Smith, V.L.; Page, D.J.; Roberts, J.S.

    1975-12-01

    Light activated multilayered silicon semiconductor devices have been used to switch at megawatt power levels with nanosecond turnon time. Current rate of rise of 700 kA/μs at 10 kA, with 1 kV across the load have been achieved. Recovery time of 1 millisec has been obtained. Applicability to fusion research needs is discussed

  13. An Electron-Beam Controlled Semiconductor Switch

    Science.gov (United States)

    1989-11-01

    of the Seventeenth Power Modulator Symposium, Seattle, WA, pp. 214-218. 1986. 21. Bovino , L., ’ioumans,R., Weiner, H., Burke, T . , "Optica lly... Bovino , R. Youmans, M. Weiner, and T. Burke, ’ ’Optically Co ntrolled Semiconducto r Switch for ~lulti-~legawatt Rep-Rated Pulse r s ," Conf. Record...p. 615. (II 1 W. N. Carr, IEEE Trans. Electron Devices, vol. ED-12, p. 531 , 1965. (121 T. Burke, M. Weiner. L. Bovino , and R. Youmans, in Proc

  14. Optical switching of nuclear spin-spin couplings in semiconductors.

    Science.gov (United States)

    Goto, Atsushi; Ohki, Shinobu; Hashi, Kenjiro; Shimizu, Tadashi

    2011-07-05

    Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear-spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings.

  15. Optical switching of nuclear spin–spin couplings in semiconductors

    Science.gov (United States)

    Goto, Atsushi; Ohki, Shinobu; Hashi, Kenjiro; Shimizu, Tadashi

    2011-01-01

    Two-qubit operation is an essential part of quantum computation. However, solid-state nuclear magnetic resonance quantum computing has not been able to fully implement this functionality, because it requires a switchable inter-qubit coupling that controls the time evolutions of entanglements. Nuclear dipolar coupling is beneficial in that it is present whenever nuclear–spin qubits are close to each other, while it complicates two-qubit operation because the qubits must remain decoupled to prevent unwanted couplings. Here we introduce optically controllable internuclear coupling in semiconductors. The coupling strength can be adjusted externally through light power and even allows on/off switching. This feature provides a simple way of switching inter-qubit couplings in semiconductor-based quantum computers. In addition, its long reach compared with nuclear dipolar couplings allows a variety of options for arranging qubits, as they need not be next to each other to secure couplings. PMID:21730962

  16. Active RF Pulse Compression Using An Electrically Controlled Semiconductor Switch

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jiquan; Tantawi, Sami; /SLAC

    2007-01-10

    First we review the theory of active pulse compression systems using resonant delay lines. Then we describe the design of an electrically controlled semiconductor active switch. The switch comprises an active window and an overmoded waveguide three-port network. The active window is based on a four-inch silicon wafer which has 960 PIN diodes. These are spatially combined in an overmoded waveguide. We describe the philosophy and design methodology for the three-port network and the active window. We then present the results of using this device to compress 11.4 GHz RF signals with high compression ratios. We show how the system can be used with amplifier like sources, in which one can change the phase of the source by manipulating the input to the source. We also show how the active switch can be used to compress a pulse from an oscillator like sources, which is not possible with passive pulse compression systems.

  17. Mechanism of single atom switch on silicon

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Thirstrup, C.

    1998-01-01

    We demonstrate single atom switch on silicon which operates by displacement of a hydrogen atom on the silicon (100) surface at room temperature. We find two principal effects by which the switch is controlled: a pronounced maximum of the switching probability as function of sample bias...

  18. Transparent ceramic photo-optical semiconductor high power switches

    Science.gov (United States)

    Werne, Roger W.; Sullivan, James S.; Landingham, Richard L.

    2016-01-19

    A photoconductive semiconductor switch according to one embodiment includes a structure of sintered nanoparticles of a high band gap material exhibiting a lower electrical resistance when excited by light relative to an electrical resistance thereof when not exposed to the light. A method according to one embodiment includes creating a mixture comprising particles, at least one dopant, and at least one solvent; adding the mixture to a mold; forming a green structure in the mold; and sintering the green structure to form a transparent ceramic. Additional system, methods and products are also presented.

  19. Operation of a semiconductor opening switch at ultrahigh current densities

    International Nuclear Information System (INIS)

    Lyubutin, S. K.; Rukin, S. N.; Slovikovsky, B. G.; Tsyranov, S. N.

    2012-01-01

    The operation of a semiconductor opening switch (SOS diode) at cutoff current densities of tens of kA/cm 2 is studied. In experiments, the maximum reverse current density reached 43 kA/cm 2 for ∼40 ns. Experimental data on SOS diodes with a p + -p-n-n + structure and a p-n junction depth from 145 to 180 μm are presented. The dynamics of electron-hole plasma in the diode at pumping and current cutoff stages is studied by numerical simulation methods. It is shown that current cutoff is associated with the formation of an electric field region in a thin (∼45 μm) layer of the structure’s heavily doped p-region, in which the acceptor concentration exceeds 10 16 cm −3 , and the current cutoff process depends weakly on the p-n junction depth.

  20. Single photon sources with single semiconductor quantum dots

    Science.gov (United States)

    Shan, Guang-Cun; Yin, Zhang-Qi; Shek, Chan Hung; Huang, Wei

    2014-04-01

    In this contribution, we briefly recall the basic concepts of quantum optics and properties of semiconductor quantum dot (QD) which are necessary to the understanding of the physics of single-photon generation with single QDs. Firstly, we address the theory of quantum emitter-cavity system, the fluorescence and optical properties of semiconductor QDs, and the photon statistics as well as optical properties of the QDs. We then review the localization of single semiconductor QDs in quantum confined optical microcavity systems to achieve their overall optical properties and performances in terms of strong coupling regime, efficiency, directionality, and polarization control. Furthermore, we will discuss the recent progress on the fabrication of single photon sources, and various approaches for embedding single QDs into microcavities or photonic crystal nanocavities and show how to extend the wavelength range. We focus in particular on new generations of electrically driven QD single photon source leading to high repetition rates, strong coupling regime, and high collection efficiencies at elevated temperature operation. Besides, new developments of room temperature single photon emission in the strong coupling regime are reviewed. The generation of indistinguishable photons and remaining challenges for practical single-photon sources are also discussed.

  1. Investigation on properties of ultrafast switching in a bulk gallium arsenide avalanche semiconductor switch

    International Nuclear Information System (INIS)

    Hu, Long; Su, Jiancang; Ding, Zhenjie; Hao, Qingsong; Yuan, Xuelin

    2014-01-01

    Properties of ultrafast switching in a bulk gallium arsenide (GaAs) avalanche semiconductor switch based on semi-insulating wafer, triggered by an optical pulse, were analyzed using physics-based numerical simulations. It has been demonstrated that when a voltage with amplitude of 5.2 kV is applied, after an exciting optical pulse with energy of 1 μJ arrival, the structure with thickness of 650 μm reaches a high conductivity state within 110 ps. Carriers are created due to photons absorption, and electrons and holes drift to anode and cathode terminals, respectively. Static ionizing domains appear both at anode and cathode terminals, and create impact-generated carriers which contribute to the formation of electron-hole plasma along entire channel. When the electric field in plasma region increases above the critical value (∼4 kV/cm) at which the electrons drift velocity peaks, a domain comes into being. An increase in carrier concentration due to avalanche multiplication in the domains reduces the domain width and results in the formation of an additional domain as soon as the field outside the domains increases above ∼4 kV/cm. The formation and evolution of multiple powerfully avalanching domains observed in the simulations are the physical reasons of ultrafast switching. The switch exhibits delayed breakdown with the characteristics affected by biased electric field, current density, and optical pulse energy. The dependence of threshold energy of the exciting optical pulse on the biased electric field is discussed

  2. Domain switching in single-phase multiferroics

    Science.gov (United States)

    Jia, Tingting; Cheng, Zhenxiang; Zhao, Hongyang; Kimura, Hideo

    2018-06-01

    Multiferroics are a time-honoured research subject by reason for their tremendous application potential in the information industry, such as in multi-state information storage devices and new types of sensors. An outburst of studies on multiferroicity has been witnessed in the 21st century, although this field has a long research history since the 19th century. Multiferroicity has now become one of the hottest research topics in condensed matter physics and materials science. Numerous efforts have been made to investigate the cross-coupling phenomena among ferroic orders such as ferroelectricity, (anti-)ferromagnetism, and ferroelasticity, especially the coupling between electric and magnetic orderings that would account for the magnetoelectric (ME) effect in multiferroic materials. The magnetoelectric properties and coupling behavior of single phase multiferroics are dominated by their domain structures. It was also noted that, however, the multiferroic materials exhibit very complicated domain structures. Studies on domain structure characterization and domain switching are a crucial step in the exploration of approaches to the control and manipulation of magnetic (electric) properties using an electric (magnetic) field or other means. In this review, following a concise outline of our current basic knowledge on the magnetoelectric (ME) effect, we summarize some important research activities on domain switching in single-phase multiferroic materials in the form of single crystals and thin films, especially domain switching behavior involving strain and the related physics in the last decade. We also introduce recent developments in characterization techniques for domain structures of ferroelectric or multiferroic materials, which have significantly advanced our understanding of domain switching dynamics and interactions. The effects of a series of issues such as electric field, magnetic field, and stress effects on domain switching are been discussed as well. It

  3. Mouse manipulation through single-switch scanning.

    Science.gov (United States)

    Blackstien-Adler, Susie; Shein, Fraser; Quintal, Janet; Birch, Shae; Weiss, Patrice L Tamar

    2004-01-01

    Given the current extensive reliance on the graphical user interface, independent access to computer software requires that users be able to manipulate a pointing device of some type (e.g., mouse, trackball) or be able to emulate a mouse by some other means (e.g., scanning). The purpose of the present study was to identify one or more optimal single-switch scanning mouse emulation strategies. Four alternative scanning strategies (continuous Cartesian, discrete Cartesian, rotational, and hybrid quadrant/continuous Cartesian) were selected for testing based on current market availability as well as on theoretical considerations of their potential speed and accuracy. Each strategy was evaluated using a repeated measures study design by means of a test program that permitted mouse emulation via any one of four scanning strategies in a motivating environment; response speed and accuracy could be automatically recorded and considered in view of the motor, cognitive, and perceptual demands of each scanning strategy. Ten individuals whose disabilities required them to operate a computer via single-switch scanning participated in the study. Results indicated that Cartesian scanning was the preferred and most effective scanning strategy. There were no significant differences between results from the Continuous Cartesian and Discrete Cartesian scanning strategies. Rotational scanning was quite slow with respect to the other strategies, although it was equally accurate. Hybrid Quadrant scanning improved access time but at the cost of fewer correct selections. These results demonstrated the importance of testing and comparing alternate single-switch scanning strategies.

  4. Comparison of soft and hard-switching effiency in a three-level single phase 60kW dc-ac converter

    DEFF Research Database (Denmark)

    Munk-Nielsen, Stig; Teodorescu, Remus; Bech, Michael Møller

    2003-01-01

    Efficiency measurements on a three-level single-phase soft-switched converter are presented and show a slightly improved efficiency compared with the hard-switched converter for output powers higher than 25 % of rated power. The resonant converter switches are Zero Voltage Switched (ZVS......) and a simple resonant circuit is used. Increased resonant converter efficiency enables a reduction in the semiconductor size pr. watt output power or an increase the switching frequency....

  5. Chemical switches and logic gates based on surface modified semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Konrad, Szacilowski; Wojciech, Macyk [Jagiellonian Univ., Dept. of Chemistry, Krakow (Poland)

    2006-02-15

    Photoelectrochemical properties of multicomponent photo-electrodes based on titanium dioxide and cadmium sulfide powders modified with hexacyanoferrate complexes have been examined. Photocurrent responses were recorded as functions of applied potential and photon energy. Surprisingly, the photocurrent can be switched between positive and negative values as a result of potential or photon energy changes. This new effect called Photo Electrochemical Photocurrent Switching (PEPS) opens a possibility of new chemical switches and logic gates construction. Boolean logic analysis and a tentative mechanism of the device are discussed. (authors)

  6. Bipolar resistive switching in metal-insulator-semiconductor nanostructures based on silicon nitride and silicon oxide

    Science.gov (United States)

    Koryazhkina, M. N.; Tikhov, S. V.; Mikhaylov, A. N.; Belov, A. I.; Korolev, D. S.; Antonov, I. N.; Karzanov, V. V.; Gorshkov, O. N.; Tetelbaum, D. I.; Karakolis, P.; Dimitrakis, P.

    2018-03-01

    Bipolar resistive switching in metal-insulator-semiconductor (MIS) capacitor-like structures with an inert Au top electrode and a Si3N4 insulator nanolayer (6 nm thick) has been observed. The effect of a highly doped n +-Si substrate and a SiO2 interlayer (2 nm) is revealed in the changes in the semiconductor space charge region and small-signal parameters of parallel and serial equivalent circuit models measured in the high- and low-resistive capacitor states, as well as under laser illumination. The increase in conductivity of the semiconductor capacitor plate significantly reduces the charging and discharging times of capacitor-like structures.

  7. Fully tunable 360° microwave photonic phase shifter based on a single semiconductor optical amplifier.

    Science.gov (United States)

    Sancho, Juan; Lloret, Juan; Gasulla, Ivana; Sales, Salvador; Capmany, José

    2011-08-29

    A fully tunable microwave photonic phase shifter involving a single semiconductor optical amplifier (SOA) is proposed and demonstrated. 360° microwave phase shift has been achieved by tuning the carrier wavelength and the optical input power injected in an SOA while properly profiting from the dispersion feature of a conveniently designed notch filter. It is shown that the optical filter can be advantageously employed to switch between positive and negative microwave phase shifts. Numerical calculations corroborate the experimental results showing an excellent agreement.

  8. Multi-Valued Spin Switch in a Semiconductor Microcavity

    Science.gov (United States)

    Paraïso, T. K.; Wouters, M.; Léger, Y.; Morier-Genoud, F.; Deveaudhyphen; Plédran, B.

    2011-12-01

    In this work, we report on the first realization of multi-valued spin switching in the solid-state. We investigate the physics of spinor bistability with microcavity polaritons in a trap. Spinor interactions lead to special bistability regimes with decoupled thresholds for spin-up and spin-down polaritons. This allows us to establish state-of-the-art spin switching operations. We evidence polarization hysteresis and determine appropriate conditions to achieve spin multistability. For a given excitation condition, three stable spin states coexist for the system. These results open new pathways for the development of innovative spin-based logic gates and memory devices.

  9. Solution-printed organic semiconductor blends exhibiting transport properties on par with single crystals.

    Science.gov (United States)

    Niazi, Muhammad R; Li, Ruipeng; Qiang Li, Er; Kirmani, Ahmad R; Abdelsamie, Maged; Wang, Qingxiao; Pan, Wenyang; Payne, Marcia M; Anthony, John E; Smilgies, Detlef-M; Thoroddsen, Sigurdur T; Giannelis, Emmanuel P; Amassian, Aram

    2015-11-23

    Solution-printed organic semiconductors have emerged in recent years as promising contenders for roll-to-roll manufacturing of electronic and optoelectronic circuits. The stringent performance requirements for organic thin-film transistors (OTFTs) in terms of carrier mobility, switching speed, turn-on voltage and uniformity over large areas require performance currently achieved by organic single-crystal devices, but these suffer from scale-up challenges. Here we present a new method based on blade coating of a blend of conjugated small molecules and amorphous insulating polymers to produce OTFTs with consistently excellent performance characteristics (carrier mobility as high as 6.7 cm(2) V(-1) s(-1), low threshold voltages oforganic semiconductor films with transport properties and other figures of merit on par with their single-crystal counterparts.

  10. ABC-model analysis of gain-switched pulse characteristics in low-dimensional semiconductor lasers

    Science.gov (United States)

    Bao, Xumin; Liu, Yuejun; Weng, Guoen; Hu, Xiaobo; Chen, Shaoqiang

    2018-01-01

    The gain-switching dynamics of low-dimensional semiconductor lasers is simulated numerically by using a two-dimensional rate-equation model. Use is also made of the ABC model, where the carrier recombination rate is described by a function of carrier densities including Shockley - Read - Hall (SRH) recombination coefficient A, spontaneous emission coefficient B and Auger recombination coefficient C. Effects of the ABC parameters on the ultrafast gain-switched pulse characteristics with high-density pulse excitation are analysed. It is found that while the parameter A has almost no obvious effects, the parameters B and C have distinctly different effects: B influences significantly the delay time of the gain-switched pulse, while C affects mainly the pulse intensity.

  11. Single Switch Nonisolated Ultra-Step-Up DC-DC Converter with an Integrated Coupled Inductor for High Boost Applications

    DEFF Research Database (Denmark)

    Siwakoti, Yam P.; Blaabjerg, Frede

    2017-01-01

    This paper introduces a new single-switch nonisolated dc-dc converter with very high voltage gain and reduced semiconductor voltage stress. The converter utilizes an integrated autotransformer and a coupled inductor on the same core in order to achieve a very high voltage gain without using extreme...... duty cycle. Furthermore, a passive lossless clamp circuit recycles the leakage energy of the coupled magnetics and alleviates the voltage spikes across the main switch. This feature along with low stress on the switching device enables the designer to use a low voltage and low RDS-on MOSFET, which...

  12. Modeling of Semiconductor Optical Amplifier Gain Characteristics for Amplification and Switching

    Science.gov (United States)

    Mahad, Farah Diana; Sahmah, Abu; Supa'at, M.; Idrus, Sevia Mahdaliza; Forsyth, David

    2011-05-01

    The Semiconductor Optical Amplifier (SOA) is presently commonly used as a booster or pre-amplifier in some communication networks. However, SOAs are also a strong candidate for utilization as multi-functional elements in future all-optical switching, regeneration and also wavelength conversion schemes. With this in mind, the purpose of this paper is to simulate the performance of the SOA for improved amplification and switching functions. The SOA is modeled and simulated using OptSim software. In order to verify the simulated results, a MATLAB mathematical model is also used to aid the design of the SOA. Using the model, the gain difference between simulated and mathematical results in the unsaturated region is <1dB. The mathematical analysis is in good agreement with the simulation result, with only a small offset due to inherent software limitations in matching the gain dynamics of the SOA.

  13. Experimental and theoretical investigation of semiconductor optical amplifier (SOA) based all-optical switches

    DEFF Research Database (Denmark)

    Nielsen, Mads Lønstrup

    2004-01-01

    This thesis analyzes semiconductor optical amplifier (SOA) based all-optical switches experimentally and through numerical simulations. These devices are candidates for optical signal processing functionalities such as wavelength conversion, regeneration, and logic processing in future transparent......, consisting of an SOA and an asymmetric MZI filter, is analyzed in the small-signal regime, and the obtainable modulation bandwidth is expressed analytically. A new optical spectrum approach to small signal analysis is introduced, and is used to assess the bandwidth enhancing effect of different optical...... filters, as well the impact of the filter phase response. Experiments at 40 Gb/s verify the predictions of the small-signal analysis. Wavelength conversion is demonstrated experimentally at 40 Gb/s using a simple filtering-assisted scheme with an ultra-low optical switching energy, and up to 80 Gb...

  14. Development of all-solid-state flash x-ray generator with photoconductive semiconductor switches

    Energy Technology Data Exchange (ETDEWEB)

    Xun, Ma; Jianjun, Deng; Hongwei, Liu; Jianqiang, Yuan; Jinfeng, Liu; Bing, Wei; Yanling, Qing; Wenhui, Han; Lingyun, Wang; Pin, Jiang; Hongtao, Li [Key Laboratory of Pulsed Power, Institute of Fluid Physics, CAEP, P.O. Box 919-108, Mianyang 621900 (China)

    2014-09-15

    A compact, low-jitter, and high repetitive rate all-solid-state flash x-ray generator making use of photo conductive semiconductor switches was developed recently for the diagnostic purpose of some hydrokinetical experiments. The generator consisted of twelve stages of Blumlein pulse forming networks, and an industrial cold cathode diode was used to generate intense x-ray radiations with photon energy up to 220 keV. Test experiments showed that the generator could produce >1 kA electron beam currents and x-ray pulses with ∼40 ns duration under 100 Hz repetitive rates at least (limited by the triggering laser on hand), also found was that the delay time of the cathode explosive emission is crucial to the energy transfer efficiency of the whole system. In addition, factors affecting the diode impedance, how the switching synchronization and diode impedance determining the allowable operation voltage were discussed.

  15. Development of all-solid-state flash x-ray generator with photoconductive semiconductor switches.

    Science.gov (United States)

    Xun, Ma; Jianjun, Deng; Hongwei, Liu; Jianqiang, Yuan; Jinfeng, Liu; Bing, Wei; Yanling, Qing; Wenhui, Han; Lingyun, Wang; Pin, Jiang; Hongtao, Li

    2014-09-01

    A compact, low-jitter, and high repetitive rate all-solid-state flash x-ray generator making use of photo conductive semiconductor switches was developed recently for the diagnostic purpose of some hydrokinetical experiments. The generator consisted of twelve stages of Blumlein pulse forming networks, and an industrial cold cathode diode was used to generate intense x-ray radiations with photon energy up to 220 keV. Test experiments showed that the generator could produce >1 kA electron beam currents and x-ray pulses with ~40 ns duration under 100 Hz repetitive rates at least (limited by the triggering laser on hand), also found was that the delay time of the cathode explosive emission is crucial to the energy transfer efficiency of the whole system. In addition, factors affecting the diode impedance, how the switching synchronization and diode impedance determining the allowable operation voltage were discussed.

  16. Wavelength switching dynamics of two-colour semiconductor lasers with optical injection and feedback

    International Nuclear Information System (INIS)

    Osborne, S; Heinricht, P; Brandonisio, N; Amann, A; O’Brien, S

    2012-01-01

    The wavelength switching dynamics of two-colour semiconductor lasers with optical injection and feedback are presented. These devices incorporate slotted regions etched into the laser ridge waveguide for tailoring the output spectrum. Experimental measurements are presented demonstrating that optical injection in one or both modes of these devices can induce wavelength bistability. Measured switching dynamics with modulated optical injection are shown to be in excellent agreement with numerical simulations based on a simple rate equation model. We also demonstrate experimentally that time-delayed optical feedback can induce wavelength bistability for short external cavity lengths. Numerical simulations indicate that this two-colour optical feedback system can provide fast optical memory functionality based on injected optical pulses without the need for an external holding beam. (paper)

  17. High-power subnanosecond operation of a bistable optically controlled semiconductor switch (BOSS)

    International Nuclear Information System (INIS)

    Stoudt, D.C.; Richardson, M.A.; Demske, D.L.; Roush, R.A.; Eure, K.W.

    1994-01-01

    Recent high-power, subnanosecond-switching results of the Bistable Optically controlled Semiconductor Switch (BOSS) are presented. The process of persistent photoconductivity followed by photo-quenching have been demonstrated at megawatt power levels in copper-compensated, silicon-doped, semi-insulating gallium arsenide. These processes allow a switch to be developed that can be closed by the application of one laser pulse and opened by the application of a second laser pulse with a wavelength equal to twice that of the first laser. Switch closure is primarily achieved by elevating electrons from a deep copper center which has been diffused into the material. The opening phase is a two-step process which relies initially on the absorption of the 2-μm laser causing electrons to be elevated from the valance band back into the copper center, and finally on the recombination of electrons in the conduction band with boles in the valance band. The second step requires a sufficient concentration of recombination centers (RC) in the material for opening to occur in the subnanosecond regime. These RC's are generated in the bulk GaAs material by fast-neutron irradiation (∼ 1 MeV) at a fluence of about 3 x 10 15 cm -2 . High-power switching results which demonstrate that the BOSS switch can be opened in the subnanosecond regime are presented for the first time. Neutron-irradiated BOSS devices have been opened against a rising electric field of about 20 kV/cm (10 kV) in a time less than one nanosecond. Kilovolt electrical pulses have been generated with a FWHM of roughly 250 picoseconds

  18. Three-dimensional charge transport in organic semiconductor single crystals.

    Science.gov (United States)

    He, Tao; Zhang, Xiying; Jia, Jiong; Li, Yexin; Tao, Xutang

    2012-04-24

    Three-dimensional charge transport anisotropy in organic semiconductor single crystals - both plates and rods (above and below, respectively, in the figure) - is measured in well-performing organic field-effect transistors for the first time. The results provide an excellent model for molecular design and device preparation that leads to good performance. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. A Novel Single Phase Hybrid Switched Reluctance Motor Drive System

    DEFF Research Database (Denmark)

    Liang, Jianing; Xu, Guoqing; Jian, Linni

    2011-01-01

    In this paper, a novel single phase hybrid switched reluctance motor(SRM) drive system is proposed. It integrated a single phase hybrid SRM and a novel single phase boost converter. This motor can reduce the number of phase switch. And the permanent magnet which is used in the motor can improve...... the performance and efficiency of SR motor. However, the inherent characteristic of this motor is that the negative torque is very sensitive with the excitation current near the turn-on angle. The slow excitation current limits the torque generation region and reduces the average torque. Therefore, a novel single...... phase boost converter is applied to improve the performance of this motor. It is easy to generate a double dclink voltage and dc-link voltage and switch both of them. The voltage of boost capacitor is self balance, so the protective circuit is not need to consider. The fast excitation mode helps hybrid...

  20. Development of high power X-band semiconductor microwave switch for pulse compression systems of future linear colliders

    Directory of Open Access Journals (Sweden)

    Fumihiko Tamura

    2002-06-01

    Full Text Available We describe concepts for high power semiconductor rf switches, designed to handle signals at X-band with power level near 100 MW. We describe an abstract design methodology and derive a general scaling law for these switches. We also present a design and experimental work of a switch operating at the TE_{01} mode in overmoded circular waveguides. The switch is composed of an array of tee junction elements that have a p-i-n diode array window in the third arm.

  1. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    International Nuclear Information System (INIS)

    Schwarze, G.E.; Frasca, A.J.

    1994-01-01

    The effects of neutrons and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10 13 n/cm 2 and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are given in this paper. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed

  2. Neutron, gamma ray and post-irradiation thermal annealing effects on power semiconductor switches

    Science.gov (United States)

    Schwarze, G. E.; Frasca, A. J.

    1991-01-01

    The effects of neutron and gamma rays on the electrical and switching characteristics of power semiconductor switches must be known and understood by the designer of the power conditioning, control, and transmission subsystem of space nuclear power systems. The SP-100 radiation requirements at 25 m from the nuclear source are a neutron fluence of 10(exp 13) n/sq cm and a gamma dose of 0.5 Mrads. Experimental data showing the effects of neutrons and gamma rays on the performance characteristics of power-type NPN Bipolar Junction Transistors (BJTs), Metal-Oxide-Semiconductor Field Effect Transistors (MOSFETs), and Static Induction Transistors (SITs) are presented. These three types of devices were tested at radiation levels which met or exceeded the SP-100 requirements. For the SP-100 radiation requirements, the BJTs were found to be most sensitive to neutrons, the MOSFETs were most sensitive to gamma rays, and the SITs were only slightly sensitive to neutrons. Post-irradiation thermal anneals at 300 K and up to 425 K were done on these devices and the effectiveness of these anneals are also discussed.

  3. Single electron-spin memory with a semiconductor quantum dot

    International Nuclear Information System (INIS)

    Young, Robert J; Dewhurst, Samuel J; Stevenson, R Mark; Atkinson, Paola; Bennett, Anthony J; Ward, Martin B; Cooper, Ken; Ritchie, David A; Shields, Andrew J

    2007-01-01

    We show storage of the circular polarization of an optical field, transferring it to the spin-state of an individual electron confined in a single semiconductor quantum dot. The state is subsequently read out through the electronically-triggered emission of a single photon. The emitted photon shares the same polarization as the initial pulse but has a different energy, making the transfer of quantum information between different physical systems possible. With an applied magnetic field of 2 T, spin memory is preserved for at least 1000 times more than the exciton's radiative lifetime

  4. Light-Induced Switching of Tunable Single-Molecule Junctions

    KAUST Repository

    Sendler, Torsten

    2015-04-16

    A major goal of molecular electronics is the development and implementation of devices such as single-molecular switches. Here, measurements are presented that show the controlled in situ switching of diarylethene molecules from their nonconductive to conductive state in contact to gold nanoelectrodes via controlled light irradiation. Both the conductance and the quantum yield for switching of these molecules are within a range making the molecules suitable for actual devices. The conductance of the molecular junctions in the opened and closed states is characterized and the molecular level E 0, which dominates the current transport in the closed state, and its level broadening Γ are identified. The obtained results show a clear light-induced ring forming isomerization of the single-molecule junctions. Electron withdrawing side-groups lead to a reduction of conductance, but do not influence the efficiency of the switching mechanism. Quantum chemical calculations of the light-induced switching processes correlate these observations with the fundamentally different low-lying electronic states of the opened and closed forms and their comparably small modification by electron-withdrawing substituents. This full characterization of a molecular switch operated in a molecular junction is an important step toward the development of real molecular electronics devices.

  5. Light-Induced Switching of Tunable Single-Molecule Junctions

    KAUST Repository

    Sendler, Torsten; Luka-Guth, Katharina; Wieser, Matthias; Lokamani; Wolf, Jannic Sebastian; Helm, Manfred; Gemming, Sibylle; Kerbusch, Jochen; Scheer, Elke; Huhn, Thomas; Erbe, Artur

    2015-01-01

    A major goal of molecular electronics is the development and implementation of devices such as single-molecular switches. Here, measurements are presented that show the controlled in situ switching of diarylethene molecules from their nonconductive to conductive state in contact to gold nanoelectrodes via controlled light irradiation. Both the conductance and the quantum yield for switching of these molecules are within a range making the molecules suitable for actual devices. The conductance of the molecular junctions in the opened and closed states is characterized and the molecular level E 0, which dominates the current transport in the closed state, and its level broadening Γ are identified. The obtained results show a clear light-induced ring forming isomerization of the single-molecule junctions. Electron withdrawing side-groups lead to a reduction of conductance, but do not influence the efficiency of the switching mechanism. Quantum chemical calculations of the light-induced switching processes correlate these observations with the fundamentally different low-lying electronic states of the opened and closed forms and their comparably small modification by electron-withdrawing substituents. This full characterization of a molecular switch operated in a molecular junction is an important step toward the development of real molecular electronics devices.

  6. 1-D position sensitive single carrier semiconductor detectors

    International Nuclear Information System (INIS)

    Zhong He; Knoll, G.F.; Wehe, D.K.; Rojeski, R.; Mastrangelo, C.H.; Hammig, M.; Barrett, C.; Uritani, A.

    1996-01-01

    A single polarity charge sensing method has been studied using coplanar electrodes on 5 mm cubes of CdZnTe γ-ray detectors. This method can ameliorate the hole trapping problem of room-temperature semiconductor detectors. Our experimental results confirm that the energy resolution is dramatically improved compared with that obtained using the conventional readout method, but is still about an order of magnitude worse than the theoretical limit. A method to obtain the γ-ray interaction depth between the cathode and the anode is presented here. This technique could be used to correct for the electron trapping as a function of distance from the coplanar electrodes. Experimental results showed that a position resolution of about 0.9 mm FWHM at 122 keV can be obtained. These results will be of interest in the design of higher performance room-temperature semiconductor γ-ray detectors. (orig.)

  7. Semiconductor

    International Nuclear Information System (INIS)

    2000-01-01

    This book deals with process and measurement of semiconductor. It contains 20 chapters, which goes as follows; semiconductor industry, introduction of semiconductor manufacturing, yield of semiconductor process, materials, crystal growth and a wafer forming, PN, control pollution, oxidation, photomasking photoresist chemistry, photomasking technologies, diffusion and ion injection, chemical vapor deposition, metallization, wafer test and way of evaluation, semiconductor elements, integrated circuit and semiconductor circuit technology.

  8. Semiconductor ring lasers coupled by a single waveguide

    Science.gov (United States)

    Coomans, W.; Gelens, L.; Van der Sande, G.; Mezosi, G.; Sorel, M.; Danckaert, J.; Verschaffelt, G.

    2012-06-01

    We experimentally and theoretically study the characteristics of semiconductor ring lasers bidirectionally coupled by a single bus waveguide. This configuration has, e.g., been suggested for use as an optical memory and as an optical neural network motif. The main results are that the coupling can destabilize the state in which both rings lase in the same direction, and it brings to life a state with equal powers at both outputs. These are both undesirable for optical memory operation. Although the coupling between the rings is bidirectional, the destabilization occurs due to behavior similar to an optically injected laser system.

  9. Passively Q-switched dual-wavelength thulium-doped fiber laser based on a multimode interference filter and a semiconductor saturable absorber

    Science.gov (United States)

    Wang, M.; Huang, Y. J.; Ruan, S. C.

    2018-04-01

    In this paper, we have demonstrated a theta cavity passively Q-switched dual-wavelength fiber laser based on a multimode interference filter and a semiconductor saturable absorber. Relying on the properties of the fiber theta cavity, the laser can operate unidirectionally without an optical isolator. A semiconductor saturable absorber played the role of passive Q-switch while a section of single-mode-multimode-single-mode fiber structure served as an multimode interference filter and was used for selecting the lasing wavelengths. By suitably manipulating the polarization controller, stable dual-wavelength Q-switched operation was obtained at ~1946.8 nm and ~1983.8 nm with maximum output power and minimum pulse duration of ~47 mW and ~762.5 ns, respectively. The pulse repetition rate can be tuned from ~20.2 kHz to ~79.7 kHz by increasing the pump power from ~2.12 W to ~5.4 W.

  10. Phase diagrams and switching of voltage and magnetic field in dilute magnetic semiconductor nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Escobedo, R. [Departamento de Matematica Aplicada y Ciencias de la Computacion, Universidad de Cantabria, 39005 Santander (Spain); Carretero, M.; Bonilla, L.L. [G. Millan Institute, Fluid Dynamics, Nanoscience and Industrial Maths., Universidad Carlos III de Madrid, 28911 Leganes (Spain); Unidad Asociada al Instituto de Ciencia de Materiales, CSIC, 28049 Cantoblanco, Madrid (Spain); Platero, G. [Instituto de Ciencia de Materiales, CSIC, 28049 Cantoblanco, Madrid (Spain)

    2010-04-15

    The response of an n-doped dc voltage biased II-VI multi-quantum well dilute magnetic semiconductor nanostructure having its first well doped with magnetic (Mn) impurities is analyzed by sweeping wide ranges of both the voltage and the Zeeman level splitting induced by an external magnetic field. The level splitting versus voltage phase diagram shows regions of stable self-sustained current oscillations immersed in a region of stable stationary states. Transitions between stationary states and self-sustained current oscillations are systematically analyzed by both voltage and level splitting abrupt switching. Sudden voltage or/and magnetic field changes may switch on current oscillations from an initial stationary state, and reciprocally, current oscillations may disappear after sudden changes of voltage or/and magnetic field changes into the stable stationary states region. The results show how to design such a device to operate as a spin injector and a spin oscillator by tuning the Zeeman splitting (through the applied external magnetic field), the applied voltage and the sample configuration parameters (doping density, barrier and well widths, etc.) to select the desired stationary or oscillatory behavior. Phase diagram of Zeeman level splitting {delta} vs. dimensionless applied voltage {phi} for N = 10 QWs. White region: stable stationary states; black: stable self-sustained current oscillations. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Solution-printed organic semiconductor blends exhibiting transport properties on par with single crystals

    KAUST Repository

    Niazi, Muhammad Rizwan; Li, Ruipeng; Li, Erqiang; Kirmani, Ahmad R.; Abdelsamie, Maged; Wang, Qingxiao; Pan, Wenyang; Payne, Marcia M.; Anthony, John E.; Smilgies, Detlef-M.; Thoroddsen, Sigurdur T; Giannelis, Emmanuel P.; Amassian, Aram

    2015-01-01

    Solution-printed organic semiconductors have emerged in recent years as promising contenders for roll-to-roll manufacturing of electronic and optoelectronic circuits. The stringent performance requirements for organic thin-film transistors (OTFTs) in terms of carrier mobility, switching speed, turn-on voltage and uniformity over large areas require performance currently achieved by organic single-crystal devices, but these suffer from scale-up challenges. Here we present a new method based on blade coating of a blend of conjugated small molecules and amorphous insulating polymers to produce OTFTs with consistently excellent performance characteristics (carrier mobility as high as 6.7 cm2 V−1 s−1, low threshold voltages of<1 V and low subthreshold swings <0.5 V dec−1). Our findings demonstrate that careful control over phase separation and crystallization can yield solution-printed polycrystalline organic semiconductor films with transport properties and other figures of merit on par with their single-crystal counterparts.

  12. Solution-printed organic semiconductor blends exhibiting transport properties on par with single crystals

    KAUST Repository

    Niazi, Muhammad Rizwan

    2015-11-23

    Solution-printed organic semiconductors have emerged in recent years as promising contenders for roll-to-roll manufacturing of electronic and optoelectronic circuits. The stringent performance requirements for organic thin-film transistors (OTFTs) in terms of carrier mobility, switching speed, turn-on voltage and uniformity over large areas require performance currently achieved by organic single-crystal devices, but these suffer from scale-up challenges. Here we present a new method based on blade coating of a blend of conjugated small molecules and amorphous insulating polymers to produce OTFTs with consistently excellent performance characteristics (carrier mobility as high as 6.7 cm2 V−1 s−1, low threshold voltages of<1 V and low subthreshold swings <0.5 V dec−1). Our findings demonstrate that careful control over phase separation and crystallization can yield solution-printed polycrystalline organic semiconductor films with transport properties and other figures of merit on par with their single-crystal counterparts.

  13. Phase locking of a semiconductor double-quantum-dot single-atom maser

    Science.gov (United States)

    Liu, Y.-Y.; Hartke, T. R.; Stehlik, J.; Petta, J. R.

    2017-11-01

    We experimentally study the phase stabilization of a semiconductor double-quantum-dot (DQD) single-atom maser by injection locking. A voltage-biased DQD serves as an electrically tunable microwave frequency gain medium. The statistics of the maser output field demonstrate that the maser can be phase locked to an external cavity drive, with a resulting phase noise L =-99 dBc/Hz at a frequency offset of 1.3 MHz. The injection locking range, and the phase of the maser output relative to the injection locking input tone are in good agreement with Adler's theory. Furthermore, the electrically tunable DQD energy level structure allows us to rapidly switch the gain medium on and off, resulting in an emission spectrum that resembles a frequency comb. The free running frequency comb linewidth is ≈8 kHz and can be improved to less than 1 Hz by operating the comb in the injection locked regime.

  14. Method of Promoting Single Crystal Growth During Melt Growth of Semiconductors

    Science.gov (United States)

    Su, Ching-Hua (Inventor)

    2013-01-01

    The method of the invention promotes single crystal growth during fabrication of melt growth semiconductors. A growth ampoule and its tip have a semiconductor source material placed therein. The growth ampoule is placed in a first thermal environment that raises the temperature of the semiconductor source material to its liquidus temperature. The growth ampoule is then transitioned to a second thermal environment that causes the semiconductor source material in the growth ampoule's tip to attain a temperature that is below the semiconductor source material's solidus temperature. The growth ampoule so-transitioned is then mechanically perturbed to induce single crystal growth at the growth ampoule's tip.

  15. Modeling bidirectionally coupled single-mode semiconductor lasers

    International Nuclear Information System (INIS)

    Mulet, Josep; Masoller, Cristina; Mirasso, Claudio R.

    2002-01-01

    We develop a dynamical model suitable for the description of two mutually coupled semiconductor lasers in a face-to-face configuration. Our study considers the propagation of the electric field along the compound system as well as the evolution of the carrier densities within each semiconductor laser. Mutual injection, passive optical feedback, and multiple reflections are accounted for in this framework, although under weak to moderate coupling conditions. We systematically describe the effect of the coupling strength on the spectrum of monochromatic solutions and on the respective dynamical behavior. By assuming single-longitudinal-mode operation, weak mutual coupling and slowly varying approximation, the dynamical model can be reduced to rate equations describing the mutual injection from one laser to its counterpart and vice versa. A good agreement between the complete and simplified models is found for small coupling. For larger coupling, higher-order terms lead to a smaller threshold reduction, reflected itself in the spectrum of the monochromatic solutions and in the dynamics of the optical power

  16. Fast and flexible selection with a single switch.

    Directory of Open Access Journals (Sweden)

    Tamara Broderick

    Full Text Available Selection methods that require only a single-switch input, such as a button click or blink, are potentially useful for individuals with motor impairments, mobile technology users, and individuals wishing to transmit information securely. We present a single-switch selection method, "Nomon," that is general and efficient. Existing single-switch selection methods require selectable options to be arranged in ways that limit potential applications. By contrast, traditional operating systems, web browsers, and free-form applications (such as drawing place options at arbitrary points on the screen. Nomon, however, has the flexibility to select any point on a screen. Nomon adapts automatically to an individual's clicking ability; it allows a person who clicks precisely to make a selection quickly and allows a person who clicks imprecisely more time to make a selection without error. Nomon reaps gains in information rate by allowing the specification of beliefs (priors about option selection probabilities and by avoiding tree-based selection schemes in favor of direct (posterior inference. We have developed both a Nomon-based writing application and a drawing application. To evaluate Nomon's performance, we compared the writing application with a popular existing method for single-switch writing (row-column scanning. Novice users wrote 35% faster with the Nomon interface than with the scanning interface. An experienced user (author TB, with 10 hours practice wrote at speeds of 9.3 words per minute with Nomon, using 1.2 clicks per character and making no errors in the final text.

  17. A 380 V High Efficiency and High Power Density Switched-Capacitor Power Converter using Wide Band Gap Semiconductors

    DEFF Research Database (Denmark)

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

    2018-01-01

    . This paper presents such a high voltage low power switched-capacitor DC-DC converter with an input voltage upto 380 V (compatible with rectified European mains) and an output power experimentally validated up to 21.3 W. The wideband gap semiconductor devices of GaN switches and SiC diodes are combined...... to compose the proposed power stage. Their switching and loss characteristics are analyzed with transient waveforms and thermal images. Different isolated driving circuits are compared and a compact isolated halfbridge driving circuit is proposed. The full-load efficiencies of 98.3% and 97.6% are achieved......State-of-the-art switched-capacitor DC-DC power converters mainly focus on low voltage and/or high power applications. However, at high voltage and low power levels, new designs are anticipated to emerge and a power converter that has both high efficiency and high power density is highly desirable...

  18. Three new DC-to-DC Single-Switch Converters

    Directory of Open Access Journals (Sweden)

    Barry W. Williams

    2017-06-01

    Full Text Available This paper presents a new family of three previously unidentified dc-to-dc converters, buck, boost, and buck-boost voltage-transfer-function topologies, which offer advantageous transformer coupling features and low capacitor dc voltage stressing. The three single-switch, single-diode, converters offer the same features as basic dc-to-dc converters, such as the buck function with continuous output current and the boost function with continuous input current. Converter time-domain simulations and experimental results (including transformer coupling support and extol the dc-to-dc converter concepts and analysis presented.

  19. Programmed Switching of Single Polymer Conformation on DNA Origami

    DEFF Research Database (Denmark)

    Krissanaprasit, Abhichart; Madsen, Mikael; Knudsen, Jakob Bach

    2016-01-01

    -molecule conjugated polymer. The polymer is functionalized with short single-stranded (ss) DNA strands that extend from the backbone of the polymer and serve as handles. The DNA polymer conjugate can be aligned on DNA origami in three well-defined geometries (straight line, left-turned, and right-turned pattern......) by DNA hybridization directed by single-stranded guiding strands and ssDNA tracks extending from the origami surface and polymer handle. We demonstrate switching of a conjugated organic polymer conformation between left- and right-turned conformations of the polymer on DNA origami based on toehold...

  20. Ultrafast Switching Superjunction MOSFETs for Single Phase PFC Applications

    DEFF Research Database (Denmark)

    Hernandez Botella, Juan Carlos; Petersen, Lars Press; Andersen, Michael A. E.

    2014-01-01

    This paper presents a guide on characterizing state-of-the-art silicon superjunction (SJ) devices in the 600V range for single phase power factor correction (PFC) applications. The characterization procedure is based on a minimally inductive double pulse tester (DPT) with a very low intrusive...... current measurement method, which enables reaching the switching speed limits of these devices. Due to the intrinsic low and non-linear capacitances in vertical SJ MOSFETs, special attention needs to be paid to the gate drive design to minimize oscillations and limit the maximum at turn off. This paper...

  1. Operation and Modulation of H7 Current Source Inverter with Hybrid SiC and Si Semiconductor Switches

    DEFF Research Database (Denmark)

    Wang, Weiqi; Gao, Feng; Yang, Yongheng

    2018-01-01

    This paper proposes an H7 current source inverter (CSI) consisting of a single parallel-connected silicon carbide (SiC) switch and a traditional silicon (Si) H6 CSI. The proposed H7 CSI takes the advantages of the SiC switch to maintain high efficiency, while significantly increasing the switching...... as an all-SiC-switch converter in terms of high performance and high efficiency with reduced DC inductance. It provides a cost-effective solution to addressing the efficiency issue of conventional CSI systems. Simulations and experiments are performed to validate the effectiveness of the proposed H7 CSI...

  2. On the Integration of Wide Band-gap Semiconductors in Single Phase Boost PFC Converters

    DEFF Research Database (Denmark)

    Hernandez Botella, Juan Carlos

    Power semiconductor technology has dominated the evolution of switched mode power supplies (SMPS). Advances in silicon (Si) technology, as the introduction of metal oxide field effect transistor (MOSFET), isolated gate bipolar transistors (IGBT), superjunction vertical structures and Schottky...... diodes, or the introduction of silicon carbide (SiC) diodes, provided large steps in miniaturization and efficiency improvement of switched mode power converters. Gallium nitride (GaN) and SiC semiconductor devices have already been around for some years. The first one proliferated due to the necessity...... of high frequency operation in optoelectronics applications. On the other hand, Schottky SiC power diodes were introduced in 2001 as an alternative to eliminate reverse recovery issues in Si rectifiers. Wide band-gap semiconductors offer an increased electrical field strength and electron mobility...

  3. Optimization of magnetic switches for single particle and cell transport

    Energy Technology Data Exchange (ETDEWEB)

    Abedini-Nassab, Roozbeh; Yellen, Benjamin B., E-mail: yellen@duke.edu [Department of Mechanical Engineering and Materials Science, Duke University, Box 90300 Hudson Hall, Durham, North Carolina 27708 (United States); Joint Institute, University of Michigan—Shanghai Jiao Tong University, Shanghai Jiao Tong University, Shanghai 200240 (China); Murdoch, David M. [Department of Medicine, Duke University, Durham, North Carolina 27708 (United States); Kim, CheolGi [Department of Emerging Materials Science, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 711-873 (Korea, Republic of)

    2014-06-28

    The ability to manipulate an ensemble of single particles and cells is a key aim of lab-on-a-chip research; however, the control mechanisms must be optimized for minimal power consumption to enable future large-scale implementation. Recently, we demonstrated a matter transport platform, which uses overlaid patterns of magnetic films and metallic current lines to control magnetic particles and magnetic-nanoparticle-labeled cells; however, we have made no prior attempts to optimize the device geometry and power consumption. Here, we provide an optimization analysis of particle-switching devices based on stochastic variation in the particle's size and magnetic content. These results are immediately applicable to the design of robust, multiplexed platforms capable of transporting, sorting, and storing single cells in large arrays with low power and high efficiency.

  4. Switching waves dynamics in optical bistable cavity-free system at femtosecond laser pulse propagation in semiconductor under light diffraction

    Science.gov (United States)

    Trofimov, Vyacheslav A.; Egorenkov, Vladimir A.; Loginova, Maria M.

    2018-02-01

    We consider a propagation of laser pulse in a semiconductor under the conditions of an occurrence of optical bistability, which appears due to a nonlinear absorption of the semiconductor. As a result, the domains of high concentration of free charged particles (electrons and ionized donors) occur if an intensity of the incident optical pulse is greater than certain intensity. As it is well-known, that an optical beam must undergo a diffraction on (or reflection from) the domains boundaries. Usually, the beam diffraction along a coordinate of the optical pulse propagation does not take into account by using the slowly varying envelope approximation for the laser pulse interaction with optical bistable element. Therefore, a reflection of the beam from the domains with abrupt boundary does not take into account under computer simulation of the laser pulse propagation. However, the optical beams, reflected from nonhomogeneities caused by the domains of high concentration of free-charged particles, can essentially influence on a formation of switching waves in a semiconductor. We illustrate this statement by computer simulation results provided on the base of nonlinear Schrödinger equation and a set of PDEs, which describe an evolution of the semiconductor characteristics (concentrations of free-charged particles and potential of an electric field strength), and taking into account the longitudinal and transverse diffraction effects.

  5. Study of all optical switching behaviour in semiconductor microresonator with nano-active layer

    International Nuclear Information System (INIS)

    Kheradmand, R; Aryan, H

    2010-01-01

    In this paper the behaviour of carriers in spontaneous patterns formation and patterns switching has been studied. Results demonstrate that with increasing length of cavity the range of required input field amplitude for patterns formation increased slightly and also the minimum perturbation coefficient for switching decreased greatly. Increasing nonradiative recombination rate of carriers about ten percent appeared that required input field amplitude for patterns formation raised more than before, albeit the minimum perturbation coefficient for switching and switching and switching time dose not vary considerably.

  6. Study of all optical switching behaviour in semiconductor microresonator with nano-active layer

    Energy Technology Data Exchange (ETDEWEB)

    Kheradmand, R; Aryan, H, E-mail: r_kheradmand@tabrizu.ac.i, E-mail: aryan86@ms.tabrizu.ac.i [Photonics Group, Research Institute for Applied Physics and Astronomy, Tabriz University, Tabriz (Iran, Islamic Republic of)

    2010-11-01

    In this paper the behaviour of carriers in spontaneous patterns formation and patterns switching has been studied. Results demonstrate that with increasing length of cavity the range of required input field amplitude for patterns formation increased slightly and also the minimum perturbation coefficient for switching decreased greatly. Increasing nonradiative recombination rate of carriers about ten percent appeared that required input field amplitude for patterns formation raised more than before, albeit the minimum perturbation coefficient for switching and switching and switching time dose not vary considerably.

  7. Experimental investigation of limit space charge accumulation mode operation in a semi-insulating GaAs photoconductive semiconductor switch

    International Nuclear Information System (INIS)

    Ma Xiangrong; Shi Wei; Xiang Mei

    2013-01-01

    Experiments with the limited space-charge accumulation (LSA) mode of oscillation in a large gap semi-insulating (SI) GaAs photoconductive semiconductor switch (PCSS) are discussed. It has been observed that growth and drift of a photo-activated charge domain (PACD) are quenched only when the bias voltage is more than twice the threshold voltage. The original negative resistance characteristics are directly utilized in the LSA mode; during LSA operation the spatial average of the electric field varies over a large portion of the negative differential mobility region of the velocity—electric field characteristic. The work efficiency of an SI GaAs PCSS is remarkably enhanced by electric field excursions into the positive resistance region when the total electric field is only below the threshold part of the time. The LSA mode can only operate in the certain conditions that satisfy the quenching of the accumulation layer and the smaller initial domain voltage. (semiconductor devices)

  8. Unipolar resistive switching in metal oxide/organic semiconductor non-volatile memories as a critical phenomenon

    International Nuclear Information System (INIS)

    Bory, Benjamin F.; Meskers, Stefan C. J.; Rocha, Paulo R. F.; Gomes, Henrique L.; Leeuw, Dago M. de

    2015-01-01

    Diodes incorporating a bilayer of an organic semiconductor and a wide bandgap metal oxide can show unipolar, non-volatile memory behavior after electroforming. The prolonged bias voltage stress induces defects in the metal oxide with an areal density exceeding 10 17  m −2 . We explain the electrical bistability by the coexistence of two thermodynamically stable phases at the interface between an organic semiconductor and metal oxide. One phase contains mainly ionized defects and has a low work function, while the other phase has mainly neutral defects and a high work function. In the diodes, domains of the phase with a low work function constitute current filaments. The phase composition and critical temperature are derived from a 2D Ising model as a function of chemical potential. The model predicts filamentary conduction exhibiting a negative differential resistance and nonvolatile memory behavior. The model is expected to be generally applicable to any bilayer system that shows unipolar resistive switching

  9. Hybrid confocal Raman fluorescence microscopy on single cells using semiconductor quantum dots

    NARCIS (Netherlands)

    van Manen, H.J.; Otto, Cornelis

    2007-01-01

    We have overcome the traditional incompatibility of Raman microscopy with fluorescence microscopy by exploiting the optical properties of semiconductor fluorescent quantum dots (QDs). Here we present a hybrid Raman fluorescence spectral imaging approach for single-cell microscopy applications. We

  10. Concave switching in single-hop and multihop networks

    NARCIS (Netherlands)

    Walton, N.

    2015-01-01

    Switched queueing networks model wireless networks, input-queued switches, and numerous other networked communications systems. We consider an (\\(\\alpha ,g\\))-switch policy; these policies provide a generalization of the MaxWeight policies of Tassiulas and Ephremides (IEEE Trans Autom Control

  11. High-resolution photoluminescence studies of single semiconductor quantum dots

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Østergaard, John Erland; Jensen, Jacob Riis

    2000-01-01

    Semiconductor quantum dots, especially those formed by self-organized growth, are considered a promising material system for future optical devices [1] and the optical properties of quantum dot ensembles have been investigated in detail over the past years. Recently, considerable interest has...

  12. All-electric-controlled spin current switching in single-molecule magnet-tunnel junctions

    Science.gov (United States)

    Zhang, Zheng-Zhong; Shen, Rui; Sheng, Li; Wang, Rui-Qiang; Wang, Bai-Gen; Xing, Ding-Yu

    2011-04-01

    A single-molecule magnet (SMM) coupled to two normal metallic electrodes can both switch spin-up and spin-down electronic currents within two different windows of SMM gate voltage. Such spin current switching in the SMM tunnel junction arises from spin-selected single electron resonant tunneling via the lowest unoccupied molecular orbit of the SMM. Since it is not magnetically controlled but all-electrically controlled, the proposed spin current switching effect may have potential applications in future spintronics.

  13. Parasitic resistive switching uncovered from complementary resistive switching in single active-layer oxide memory device

    Science.gov (United States)

    Zhu, Lisha; Hu, Wei; Gao, Chao; Guo, Yongcai

    2017-12-01

    This paper reports the reversible transition processes between the bipolar and complementary resistive switching (CRS) characteristics on the binary metal-oxide resistive memory devices of Pt/HfO x /TiN and Pt/TaO x /TiN by applying the appropriate bias voltages. More interestingly, by controlling the amplitude of the negative bias, the parasitic resistive switching effect exhibiting repeatable switching behavior is uncovered from the CRS behavior. The electrical observation of the parasitic resistive switching effect can be explained by the controlled size of the conductive filament. This work confirms the transformation and interrelationship among the bipolar, parasitic, and CRS effects, and thus provides new insight into the understanding of the physical mechanism of the binary metal-oxide resistive switching memory devices.

  14. Spatially Mapping Energy Transfer from Single Plasmonic Particles to Semiconductor Substrates via STEM/EELS.

    Science.gov (United States)

    Li, Guoliang; Cherqui, Charles; Bigelow, Nicholas W; Duscher, Gerd; Straney, Patrick J; Millstone, Jill E; Masiello, David J; Camden, Jon P

    2015-05-13

    Energy transfer from plasmonic nanoparticles to semiconductors can expand the available spectrum of solar energy-harvesting devices. Here, we spatially and spectrally resolve the interaction between single Ag nanocubes with insulating and semiconducting substrates using electron energy-loss spectroscopy, electrodynamics simulations, and extended plasmon hybridization theory. Our results illustrate a new way to characterize plasmon-semiconductor energy transfer at the nanoscale and bear impact upon the design of next-generation solar energy-harvesting devices.

  15. Single photon sources in 4H-SiC metal-oxide-semiconductor field-effect transistors

    Science.gov (United States)

    Abe, Y.; Umeda, T.; Okamoto, M.; Kosugi, R.; Harada, S.; Haruyama, M.; Kada, W.; Hanaizumi, O.; Onoda, S.; Ohshima, T.

    2018-01-01

    We present single photon sources (SPSs) embedded in 4H-SiC metal-oxide-semiconductor field-effect transistors (MOSFETs). They are formed in the SiC/SiO2 interface regions of wet-oxidation C-face 4H-SiC MOSFETs and were not found in other C-face and Si-face MOSFETs. Their bright room-temperature photoluminescence (PL) was observed in the range from 550 to 750 nm and revealed variable multi-peak structures as well as variable peak shifts. We characterized a wide variety of their PL spectra as the inevitable variation of local atomic structures at the interface. Their polarization dependence indicates that they are formed at the SiC side of the interface. We also demonstrate that it is possible to switch on/off the SPSs by a bias voltage of the MOSFET.

  16. Tunable Injection Barrier in Organic Resistive Switches Based on Phase-Separated Ferroelectric-Semiconductor Blends

    NARCIS (Netherlands)

    Asadi, Kamal; de Boer, Tom G.; Blom, Paul W. M.; de Leeuw, Dago M.

    2009-01-01

    Organic non-volatile resistive bistable diodes based on phase-separated blends of ferroelectric and semiconducting polymers are fabricated. The polarization field of the ferroelectric modulates the injection barrier at the semiconductor-electrode contact and, hence, the resistance of the comprising

  17. Ultrawideband pulse generation based on overshooting effect in gain-switched semiconductor laser

    DEFF Research Database (Denmark)

    Torres-Company, V.; Prince, Kamau; Tafur Monroy, Idelfonso

    2008-01-01

    We demonstrate an alternative procedure to achieve ultrawideband (UWB) radio-frequency (RF) doublet impulses. It is based on the overshooting effect appearing by biasing a semiconductor laser close to the threshold with a large-amplitude signal. Specifically, with an optical bandpass filter...... a reliable, easy, and low-cost alternative for RF UWB impulse generation....

  18. Tunable injection barrier in organic resistive switches based on phase-separated ferroelectric-semiconductor blends

    NARCIS (Netherlands)

    Asadi, K.; Boer, T.G. de; Blom, P.W.M.; Leeuw, D.M. de

    2009-01-01

    Organic non-volatile resistive bistable diodes based on phase-separated blends of ferroelectric and semiconducting polymers are fabricated. The polarization field of the ferroelectric modulates the injection barrier at the semiconductor-electrode contact and, hence, the resistance of the comprising

  19. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [State Univ. of New York (SUNY), Plattsburgh, NY (United States); Univ. of California, Davis, CA (United States)

    2012-01-20

    Photoconductive semiconductor switches (PCSS) have been investigated since the late 1970s. Some devices have been developed that withstand tens of kilovolts and others that switch hundreds of amperes. However, no single device has been developed that can reliably withstand both high voltage and switch high current. Yet, photoconductive switches still hold the promise of reliable high voltage and high current operation with subnanosecond risetimes. Particularly since good quality, bulk, single crystal, wide bandgap semiconductor materials have recently become available. In this chapter we will review the basic operation of PCSS devices, status of PCSS devices and properties of the wide bandgap semiconductors 4H-SiC, 6H-SiC and 2H-GaN.

  20. 25–34 GHz Single-Pole, Double-Throw CMOS Switches for a Ka-Band Phased-Array Transceiver

    Directory of Open Access Journals (Sweden)

    Sangyong Park

    2018-01-01

    Full Text Available This paper presents two single-pole, double-throw (SPDT mm-wave switches for Ka-band phased-array transceivers, fabricated with a 65-nm complementary metal oxide semiconductor (CMOS process. One switch employs cross-biasing (CB control with a single supply, while the other uses dual-supply biasing (DSB control with positive and negative voltages. Negative voltages were generated internally, using a ring oscillator and a charge pump. Identical gate and body floated N-type metal oxide semiconductor field effect transistors (N-MOSFETs in a triple well were used as the switch core transistors. Inductors were used to improve the isolation between the transmitter (TX and receiver (RX, as well as insertion loss, by canceling the parasitic capacitance of the switch core transistors at resonance. The size of the proposed radio frequency (RF switch is 260 μm × 230 μm, excluding all pads. The minimum insertion losses of the CB and DSB switches were 2.1 dB at 28 GHz and 1.93 dB at 24 GHz, respectively. Between 25 GHz and 34 GHz, the insertion losses were less than 2.3 dB and 2.5 dB, the return losses were less than 16.7 dB and 17.3 dB, and the isolation was over 18.4 dB and 15.3 dB, respectively. The third order input intercept points (IIP3 of the CB and DSB switches were 38.4 dBm and 39 dBm at 28 GHz, respectively.

  1. Study of Power Loss Reduction in SEPR Converters for Induction Heating through Implementation of SiC Based Semiconductor Switches

    Directory of Open Access Journals (Sweden)

    Angel Marinov

    2014-08-01

    Full Text Available This paper presents a power loss analysis for a Single Ended Parallel Resonance (SEPR Converter used for induction heating. The analysis includes a comparison of the losses in the electronic switch when the circuit is realized using a conventional Silicon (Si based IGBT or when using Silicon Carbide (SiC based MOSFET. The analysis includes modelling and simulation as well as experimental verification through power loss and heat dissipation measurement. The presented results can be used as a base of comparison between the switches and can be a starting point for efficiency based design of those types of converters.

  2. Switching speed in resistive random access memories (RRAMS) based on plastic semiconductor

    NARCIS (Netherlands)

    Rocha, P.R.F.; Gomes, H.L.; Kiazadeh, A.; Chen, Qian; Leeuw, de D.M.; Meskers, S.C.J.

    2011-01-01

    This work addresses non-volatile memories based on metal-oxide polymer diodes. We make a thorough investigation into the static and dynamic behavior. Current-voltage characteristics with varying voltage ramp speed demonstrate that the internal capacitive double-layer structure inhibits the switching

  3. A Novel Single Switch Transformerless Quadratic DC/DC Buck-Boost Converter

    DEFF Research Database (Denmark)

    Mostaan, Ali; A. Gorji, Saman; N. Soltani, Mohsen

    2017-01-01

    A novel quadratic buck-boost DC/DC converter is presented in this study. The proposed converter utilizes only one active switch and can step-up/down the input voltage, while the existing single switch quadratic buck/boost converters can only work in step-up or step-down mode. First, the proposed ...

  4. Passive Fe2+ : ZnSe single-crystal Q switch for 3-mu m lasers

    NARCIS (Netherlands)

    Voronov, AA; Kozlovskii, [No Value; Korostelin, YV; Podmar'kov, YP; Polushkin, VG; Frolov, MP

    Passive Q-switching of 3-mu m lasers with the help of a Fe2+ : ZnSe single crystal is demonstrated. The 6-mJ, 50-ns giant pulses are obtained from a 2.9364-mu m Er : YAG laser by using this passive Q switch.

  5. Ultrafast Single and Multiexciton Energy Transfer in Semiconductor Nanoplatelets

    Science.gov (United States)

    Schaller, Richard

    Photophysical processes such as fluorescence resonance energy transfer (FRET) enable optical antennas, wavelength down-conversion in light-emitting diodes (LEDs), and optical bio-sensing schemes. The rate and efficiency of this donor to acceptor transfer of excitation between chromophores dictates the utility of FRET and can unlock new device operation motifs including quantum-funnel solar cells and reduced gain thresholds. However, the fastest reported FRET time constants involving spherical quantum dots (QDs) (0.12-1 ns), do not outpace biexciton Auger recombination (0.01-0.1 ns), which impedes multiexciton-driven applications including electrically-pumped lasers and carrier-multiplication-enhanced photovoltaics. Precisely controlled, few-monolayer thick semiconductor nano-platelets with tens-of-nanometer diameters exhibit intense optical transitions and hundreds-of-picosecond Auger recombination, but heretofore lack FRET characterizations. We examine binary CdSe NPL solids and show that inter-plate FRET (~6-23 ps, presumably for co-facial arrangements) can occur 15-50 times faster than Auger recombination and demonstrate multiexcitonic FRET, making such materials ideal candidates for advanced technologies. This work was performed at the Center for Nanoscale Materials, a U.S. Department of Energy Office of Science User Facility under Contract No. DE-AC02-06CH11357.

  6. An absorptive single-pole four-throw switch using multiple-contact MEMS switches and its application to a monolithic millimeter-wave beam-forming network

    International Nuclear Information System (INIS)

    Lee, Sanghyo; Kim, Jong-Man; Kim, Yong-Kweon; Kwon, Youngwoo

    2009-01-01

    In this paper, a new absorptive single-pole four-throw (SP4T) switch based on multiple-contact switching is proposed and integrated with a Butler matrix to demonstrate a monolithic beam-forming network at millimeter waves (mm waves). In order to simplify the switching driving circuit and reduce the number of unit switches in an absorptive SP4T switch, the individual switches were replaced with long-span multiple-contact switches using stress-free single-crystalline-silicon MEMS technology. This approach improves the mechanical stability as well as the manufacturing yield, thereby allowing successful integration into a monolithic beam former. The fabricated absorptive SP4T MEMS switch shows insertion loss less than 1.3 dB, return losses better than 11 dB at 30 GHz and wideband isolation performance higher than 39 dB from 20 to 40 GHz. The absorptive SP4T MEMS switch is integrated with a 4 × 4 Butler matrix on a single chip to implement a monolithic beam-forming network, directing beam into four distinct angles. Array factors from the measured data show that the proposed absorptive SPnT MEMS switch can be effectively used for high-performance mm-wave beam-switching systems. This work corresponds to the first demonstration of a monolithic beam-forming network using switched beams

  7. Voltage-Driven Conformational Switching with Distinct Raman Signature in a Single-Molecule Junction.

    Science.gov (United States)

    Bi, Hai; Palma, Carlos-Andres; Gong, Yuxiang; Hasch, Peter; Elbing, Mark; Mayor, Marcel; Reichert, Joachim; Barth, Johannes V

    2018-04-11

    Precisely controlling well-defined, stable single-molecule junctions represents a pillar of single-molecule electronics. Early attempts to establish computing with molecular switching arrays were partly challenged by limitations in the direct chemical characterization of metal-molecule-metal junctions. While cryogenic scanning probe studies have advanced the mechanistic understanding of current- and voltage-induced conformational switching, metal-molecule-metal conformations are still largely inferred from indirect evidence. Hence, the development of robust, chemically sensitive techniques is instrumental for advancement in the field. Here we probe the conformation of a two-state molecular switch with vibrational spectroscopy, while simultaneously operating it by means of the applied voltage. Our study emphasizes measurements of single-molecule Raman spectra in a room-temperature stable single-molecule switch presenting a signal modulation of nearly 2 orders of magnitude.

  8. Optically pumped semiconductor lasers: Conception and characterization of a single mode source for Cesium atoms manipulation

    International Nuclear Information System (INIS)

    Cocquelin, B.

    2009-02-01

    Lasers currently used in atomic clocks or inertial sensors are suffering from a lack of power, narrow linewidth or compactness for future spatial missions. Optically pumped semiconductor lasers, which combine the approach of classical solid state lasers and the engineering of semiconductor laser, are considered here as a candidate to a metrological laser source dedicated to the manipulation of Cesium atoms in these instruments. These lasers have demonstrated high power laser emission in a circular single transverse mode, as well as single longitudinal mode emission, favoured by the semiconductor structure and the external cavity design. We study the definition and the characterization of a proper semiconductor structure for the cooling and the detection of Cesium atoms at 852 nm. A compact and robust prototype tunable on the Cesium D2 hyperfine structure is built. The laser frequency is locked to an atomic transition thanks to a saturated absorption setup. The emission spectral properties are investigated, with a particular attention to the laser frequency noise and the laser linewidth. Finally, we describe and model the thermal properties of the semiconductor structure, which enables the simulation of the laser power characteristic. The experimental parameters are optimised to obtain the maximum output power with our structure. Thanks to our analysis, we propose several ways to overcome these limitations, by reducing the structure heating. (authors)

  9. Tuning the resistive switching memory in a metal–ferroelectric–semiconductor capacitor by field effect structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.Y., E-mail: shouyu.wang@yahoo.com [College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074 (China); Guo, F.; Wang, X. [College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074 (China); Liu, W.F., E-mail: wfliu@tju.edu.cn [Department of Applied Physics, Faculty of Science, Tianjin University, Weijin Road, Nankai District, Tianjin 300072 (China); Gao, J., E-mail: jugao@hku.hk [Department of Physics, the University of Hong Kong, Pokfulam Road (Hong Kong)

    2015-11-30

    Highlights: • Bistable or tristable electrically conducting state is observed. • Coefficient can be tuned in situ by modulating carrier's density. • The RS effects may be of significance for multi-source controlled memory devices. - Abstract: Resistive switching (RS) effects based on a correlation between ferroelectric polarization and conductivity might become of particular interest for nonvolatile memory applications, because they are not subjected to the scaling restrictions. Here we report on RS behaviors modulated by a reversal of ferroelectric polarization in heterostructures comprising of a ferroelectric layer and a semiconducting manganite film. It is found that electrically conducting state is bistable or even tristable; and via the polarization flipping, a maximum resistive switching coefficient (R{sub max}/R{sub min}) is found to be larger than 3000 with bias of 6 V in Ag/BaTiO{sub 3}/La{sub 0.8}Ca{sub 0.2}MnO{sub 3} at room temperature. More importantly, employing field-effect structure with ferroelectric PMN-PT as substrate, we found that the resistive switching behaviors can be tuned in situ by modulating the concentration of carriers in the semiconducting manganite layer. Possible mechanisms are discussed on the basis of the interplay of bound ferroelectric charges, charged defects in ferroelectric layer and mobile carriers in manganite thin films. The giant RS effects observed here may be of significance for memory devices by combing electronic conduction with magnetic, spintronic, and optical functionalities.

  10. Optimizing Two-Color Semiconductor Nanocrystal Immunoassays in Single Well Microtiter Plate Formats

    Directory of Open Access Journals (Sweden)

    W. Russ Algar

    2011-08-01

    Full Text Available The simultaneous detection of two analytes, chicken IgY (IgG and Staphylococcal enterotoxin B (SEB, in the single well of a 96-well plate is demonstrated using luminescent semiconductor quantum dot nanocrystal (NC tracers. The NC-labeled antibodies were prepared via sulfhydryl-reactive chemistry using a facile protocol that took

  11. Single-mode very wide tunability in laterally coupled semiconductor lasers with electrically controlled reflectivities

    Science.gov (United States)

    Griffel, Giora; Chen, Howard Z.; Grave, Ilan; Yariv, Amnon

    1991-04-01

    The operation of a novel multisection structure comprised of laterally coupled gain-guided semiconductor lasers is demonstrated. It is shown that tunable single longitudinal mode operation can be achieved with a high degree of frequency selectivity. The device has a tuning range of 14.5 nm, the widest observed to date in a monolithic device.

  12. Quantum optics. All-optical routing of single photons by a one-atom switch controlled by a single photon.

    Science.gov (United States)

    Shomroni, Itay; Rosenblum, Serge; Lovsky, Yulia; Bechler, Orel; Guendelman, Gabriel; Dayan, Barak

    2014-08-22

    The prospect of quantum networks, in which quantum information is carried by single photons in photonic circuits, has long been the driving force behind the effort to achieve all-optical routing of single photons. We realized a single-photon-activated switch capable of routing a photon from any of its two inputs to any of its two outputs. Our device is based on a single atom coupled to a fiber-coupled, chip-based microresonator. A single reflected control photon toggles the switch from high reflection (R ~ 65%) to high transmission (T ~ 90%), with an average of ~1.5 control photons per switching event (~3, including linear losses). No additional control fields are required. The control and target photons are both in-fiber and practically identical, making this scheme compatible with scalable architectures for quantum information processing. Copyright © 2014, American Association for the Advancement of Science.

  13. Controlled switching of single-molecule junctions by mechanical motion of a phenyl ring

    Directory of Open Access Journals (Sweden)

    Yuya Kitaguchi

    2015-10-01

    Full Text Available Mechanical methods for single-molecule control have potential for wide application in nanodevices and machines. Here we demonstrate the operation of a single-molecule switch made functional by the motion of a phenyl ring, analogous to the lever in a conventional toggle switch. The switch can be actuated by dual triggers, either by a voltage pulse or by displacement of the electrode, and electronic manipulation of the ring by chemical substitution enables rational control of the on-state conductance. Owing to its simple mechanics, structural robustness, and chemical accessibility, we propose that phenyl rings are promising components in mechanical molecular devices.

  14. Semiconductor and ceramic microstructure made by single mode fiber laser

    International Nuclear Information System (INIS)

    Pawlak, R; Tomczyk, M; Walczak, M; Domagalski, P

    2014-01-01

    In the paper the results of micromachining of 3D microstructures of microsystems made from silicon and alumina ceramic using a single mode fiber laser (1064 nm) are presented. The quality of obtained structures and its smallest dimensions with acceptable maintained quality were examined. The influence of variable parameters of laser processing with changing of mapping scale on geometrical features of structures was identified.

  15. Low mass MEMS/NEMS switch for a substitute of CMOS transistor using single-walled carbon nanotube thin film

    Science.gov (United States)

    Jang, Min-Woo

    Power dissipation is a key factor for mobile devices and other low power applications. Complementary metal oxide semiconductor (CMOS) is the dominant integrated circuit (IC) technology responsible for a large part of this power dissipation. As the minimum feature size of CMOS devices enters into the sub 50 nanometer (nm) regime, power dissipation becomes much worse due to intrinsic physical limits. Many approaches have been studied to reduce power dissipation of deeply scaled CMOS ICs. One possible candidate is the electrostatic electromechanical switch, which could be fabricated with conventional CMOS processing techniques. They have critical advantages compared to CMOS devices such as almost zero standby leakage in the off-state due to the absence of a pn junction and a gate oxide, as well as excellent drive current in the on-state due to a metallic channel. Despite their excellent standby power dissipation, the electrostatic MEMS/NEMS switches have not been considered as a viable replacement for CMOS devices due to their large mechanical delay. Moreover, previous literature reveals that their pull-in voltage and switching speed are strongly proportional to each other. This reduces their potential advantage. However, in this work, we theoretically and experimentally demonstrated that the use of single-walled carbon nanotube (SWNT) with very low mass density and strong mechanical properties could provide a route to move off of the conventional trend with respect to the pull-in voltage / switching speed tradeoff observed in the literature. We fabricated 2-terminal fixed- beam switches with aligned composite SWNT thin films. In this work, layer-by-layer (LbL) self-assembly and dielectrophoresis were selected for aligned-composite SWNT thin film deposition. The dense membranes were successfully patterned to form submicron beams by e-beam lithography and oxygen plasma etching. Fixed-fixed beam switches using these membranes successfully operated with approximately 600

  16. Single-Molecule Rotational Switch on a Dangling Bond Dimer Bearing.

    Science.gov (United States)

    Godlewski, Szymon; Kawai, Hiroyo; Kolmer, Marek; Zuzak, Rafał; Echavarren, Antonio M; Joachim, Christian; Szymonski, Marek; Saeys, Mark

    2016-09-27

    One of the key challenges in the construction of atomic-scale circuits and molecular machines is to design molecular rotors and switches by controlling the linear or rotational movement of a molecule while preserving its intrinsic electronic properties. Here, we demonstrate both the continuous rotational switching and the controlled step-by-step single switching of a trinaphthylene molecule adsorbed on a dangling bond dimer created on a hydrogen-passivated Ge(001):H surface. The molecular switch is on-surface assembled when the covalent bonds between the molecule and the dangling bond dimer are controllably broken, and the molecule is attached to the dimer by long-range van der Waals interactions. In this configuration, the molecule retains its intrinsic electronic properties, as confirmed by combined scanning tunneling microscopy/spectroscopy (STM/STS) measurements, density functional theory calculations, and advanced STM image calculations. Continuous switching of the molecule is initiated by vibronic excitations when the electrons are tunneling through the lowest unoccupied molecular orbital state of the molecule. The switching path is a combination of a sliding and rotation motion over the dangling bond dimer pivot. By carefully selecting the STM conditions, control over discrete single switching events is also achieved. Combined with the ability to create dangling bond dimers with atomic precision, the controlled rotational molecular switch is expected to be a crucial building block for more complex surface atomic-scale devices.

  17. Tracking Ultrafast Carrier Dynamics in Single Semiconductor Nanowire Heterostructures

    Directory of Open Access Journals (Sweden)

    Taylor A.J.

    2013-03-01

    Full Text Available An understanding of non-equilibrium carrier dynamics in silicon (Si nanowires (NWs and NW heterostructures is very important due to their many nanophotonic and nanoelectronics applications. Here, we describe the first measurements of ultrafast carrier dynamics and diffusion in single heterostructured Si nanowires, obtained using ultrafast optical microscopy. By isolating individual nanowires, we avoid complications resulting from the broad size and alignment distribution in nanowire ensembles, allowing us to directly probe ultrafast carrier dynamics in these quasi-one-dimensional systems. Spatially-resolved pump-probe spectroscopy demonstrates the influence of surface-mediated mechanisms on carrier dynamics in a single NW, while polarization-resolved femtosecond pump-probe spectroscopy reveals a clear anisotropy in carrier lifetimes measured parallel and perpendicular to the NW axis, due to density-dependent Auger recombination. Furthermore, separating the pump and probe spots along the NW axis enabled us to track space and time dependent carrier diffusion in radial and axial NW heterostructures. These results enable us to reveal the influence of radial and axial interfaces on carrier dynamics and charge transport in these quasi-one-dimensional nanosystems, which can then be used to tailor carrier relaxation in a single nanowire heterostructure for a given application.

  18. Radiation damage in dielectric and semiconductor single crystals (direct observation)

    CERN Document Server

    Adawi, M A; Varichenko, V S; Zaitsev, A M

    1998-01-01

    The surfaces of boron-doped synthetic and natural diamonds have been investigated by using the scanning tunnelling microscope (STM) and the scanning electronic microscope (SEM) before and after irradiating the samples with sup 4 sup 0 Ar (25 MeV), sup 8 sup 4 Kr (210 MeV) and sup 1 sup 2 sup 5 Xe (124 MeV) ions. The structures observed after irradiation showed craters with diameters ranging from 3 nm up to 20 nm, which could be interpreted as single ion tracks and multiple hits of ions at the nearest positions of the surface. In the case of argon ion irradiation, the surface was found to be completely amorphous, but after xenon irradiation one could see parts of surface without amorphism. This can be explained by the influence of high inelastic energy losses. The energy and temperature criteria of crater formation as a result of heavy ion irradiation are introduced.

  19. Fixed switching frequency applied in single-phase boost AC to DC converter

    International Nuclear Information System (INIS)

    Chen, T.-C.; Ren, T.-J.; Ou, J.-C.

    2009-01-01

    The fixed switching frequency control for a single-phase boost AC to DC converter to achieve a sinusoidal line current and unity power factor is proposed in this paper. The relation between the line current error and the fixed switching frequency was developed. For a limit line current error, the minimum switching frequency for a boost AC to DC converter can be achieved. The proposed scheme was implemented using a 32-bit digital signal processor TMS320C32. Simulations and experimental results demonstrate the feasibility and fast dynamic response of the proposed control strategy.

  20. Research on generation mechanism of single event transient current generated in the semiconductor using ion accelerator

    International Nuclear Information System (INIS)

    Hirao, Toshio

    2007-01-01

    Single-event upset (SEU) is triggered when an amount of electric charges induced by energetic ion incidence exceeds a value known as a critical charge in a very short time period. Therefore, accurate evaluation of electric charge and understanding of basic mechanism of SEU are necessary for the improvement of SEU torrance of electronic devices. In this paper, the collected charges for the single event transient current induced on semiconductor by heavy ion microbeams, and application to use microbeam for single event studies are presented. (author)

  1. Molecular electronics: the single molecule switch and transistor

    NARCIS (Netherlands)

    Sotthewes, Kai; Geskin, Victor; Heimbuch, Rene; Kumar, Avijit; Zandvliet, Henricus J.W.

    2014-01-01

    In order to design and realize single-molecule devices it is essential to have a good understanding of the properties of an individual molecule. For electronic applications, the most important property of a molecule is its conductance. Here we show how a single octanethiol molecule can be connected

  2. Development of heavy-ion irradiation technique for single-event in semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Nemoto, Norio; Akutsu, Takao; Matsuda, Sumio [National Space Development Agency of Japan, Tsukuba, Ibaraki (Japan). Tsukuba Space Center; Naitoh, Ichiro; Itoh, Hisayoshi; Agematsu, Takashi; Kamiya, Tomihiro; Nashiyama, Isamu

    1997-03-01

    Heavy-ion irradiation technique has been developed for the evaluation of single-event effects on semiconductor devices. For the uniform irradiation of high energy heavy ions to device samples, we have designed and installed a magnetic beam-scanning system in a JAERI cyclotron beam course. It was found that scanned area was approximately 4 x 2 centimeters and that the deviation of ion fluence from the average value was less than 7%. (author)

  3. A single molecule switch based on two Pd nanocrystals linked

    Indian Academy of Sciences (India)

    Conducting molecule; nanocrystals; scanning tunneling microscopy; negative differential resistance. Abstract. Tunneling spectroscopy measurements have been carried out on a single molecule device formed by two Pd ... Current Issue : Vol.

  4. Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains

    KAUST Repository

    Diao, Ying

    2013-06-02

    Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control of thin-film morphology. Here, we report an approach - termed fluid-enhanced crystal engineering (FLUENCE) - that allows for a high degree of morphological control of solution-printed thin films. We designed a micropillar-patterned printing blade to induce recirculation in the ink for enhancing crystal growth, and engineered the curvature of the ink meniscus to control crystal nucleation. Using FLUENCE, we demonstrate the fast coating and patterning of millimetre-wide, centimetre-long, highly aligned single-crystalline organic semiconductor thin films. In particular, we fabricated thin films of 6,13-bis(triisopropylsilylethynyl) pentacene having non-equilibrium single-crystalline domains and an unprecedented average and maximum mobilities of 8.1±1.2 cm2 V-1 s -1 and 11 cm2 V-1 s-1. FLUENCE of organic semiconductors with non-equilibrium single-crystalline domains may find use in the fabrication of high-performance, large-area printed electronics. © 2013 Macmillan Publishers Limited. All rights reserved.

  5. An Ultrathin Single Crystalline Relaxor Ferroelectric Integrated on a High Mobility Semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Moghadam, Reza M. [Department; Xiao, Zhiyong [Department; Ahmadi-Majlan, Kamyar [Department; Grimley, Everett D. [Department; Bowden, Mark [Environmental; amp, Biological Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Ong, Phuong-Vu [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Chambers, Scott A. [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Lebeau, James M. [Department; Hong, Xia [Department; Sushko, Peter V. [Physical; amp, Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, United States; Ngai, Joseph H. [Department

    2017-09-13

    The epitaxial growth of multifunctional oxides on semiconductors has opened a pathway to introduce new functionalities to semiconductor device technologies. In particular, ferroelectric materials integrated on semiconductors could lead to low-power field-effect devices that can be used for logic or memory. Essential to realizing such field-effect devices is the development of ferroelectric metal-oxide-semiconductor (MOS) capacitors, in which the polarization of a ferroelectric gate is coupled to the surface potential of a semiconducting channel. Here we demonstrate that ferroelectric MOS capacitors can be realized using single crystalline SrZrxTi1-xO3 (x= 0.7) that has been epitaxially grown on Ge. We find that the ferroelectric properties of SrZrxTi1-xO3 are exceptionally robust, as gate layers as thin as 5 nm give rise to hysteretic capacitance-voltage characteristics that are 2 V in width. The development of ferroelectric MOS capacitors with gate thicknesses that are technologically relevant opens a pathway to realize scalable ferroelectric field-effect devices.

  6. Investigations of quantum effect semiconductor devices: The tunnel switch diode and the velocity modulation transistor

    Science.gov (United States)

    Daniel, Erik Stephen

    In this thesis we present the results of experimental and theoretical studies of two quantum effect devices--the Tunnel Switch Diode (TSD) and the Velocity Modulation Transistor (VMT). We show that TSD devices can be fabricated such that they behave (semi-quantitatively) as predicted by simple analytical models and more advanced drift-diffusion simulations. These devices possess characteristics, such as on-state currents which range over nearly five orders of magnitude, and on/off current ratios which are even larger, which may allow for a practical implementation of a very dense transistorless SRAM architecture and possibly other novel circuit designs. We demonstrate that many TSD properties can be explained by analogy to a thyristor. In particular, we show that the thin oxide layer in the TSD plays a critical role, and that this can be understood in terms of current injection through the oxide, analogous to transport through the "current limiting" layer in a thyristor. As this oxide layer can be subjected to extreme stress during device operation, we have studied the effect of this stress on device behavior. We demonstrate many significant stress-dependent effects, and identify structures and operation modes which minimize these effects. We propose an InAs/GaSb/AlSb VMT which may allow for larger conductance modulation and higher temperature operation than has been demonstrated in similar GaAs/AlAs structures. Fundamental differences in device operation in the two materials systems and unusual transport mechanisms in the InAs/GaSb/AlSb system are identified as a result of the band lineups in the two systems. Boltzmann transport simulations are developed and presented, allowing a qualitative description of the transport in the InAs/GaSb/AlSb structure. Band structure calculations are carried out, allowing for device design. While no working VMT devices were produced, this is believed to be due to processing and crystal growth problems. We present methods used to

  7. Computer-automated tuning of semiconductor double quantum dots into the single-electron regime

    Energy Technology Data Exchange (ETDEWEB)

    Baart, T. A.; Vandersypen, L. M. K. [QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft (Netherlands); Kavli Institute of Nanoscience, Delft University of Technology, P.O. Box 5046, 2600 GA Delft (Netherlands); Eendebak, P. T. [QuTech, Delft University of Technology, P.O. Box 5046, 2600 GA Delft (Netherlands); Netherlands Organisation for Applied Scientific Research (TNO), P.O. Box 155, 2600 AD Delft (Netherlands); Reichl, C.; Wegscheider, W. [Solid State Physics Laboratory, ETH Zürich, 8093 Zürich (Switzerland)

    2016-05-23

    We report the computer-automated tuning of gate-defined semiconductor double quantum dots in GaAs heterostructures. We benchmark the algorithm by creating three double quantum dots inside a linear array of four quantum dots. The algorithm sets the correct gate voltages for all the gates to tune the double quantum dots into the single-electron regime. The algorithm only requires (1) prior knowledge of the gate design and (2) the pinch-off value of the single gate T that is shared by all the quantum dots. This work significantly alleviates the user effort required to tune multiple quantum dot devices.

  8. CMOS single-stage input-powered bridge rectifier with boost switch and duty cycle control

    Science.gov (United States)

    Radzuan, Roskhatijah; Mohd Salleh, Mohd Khairul; Hamzah, Mustafar Kamal; Ab Wahab, Norfishah

    2017-06-01

    This paper presents a single-stage input-powered bridge rectifier with boost switch for wireless-powered devices such as biomedical implants and wireless sensor nodes. Realised using CMOS process technology, it employs a duty cycle switch control to achieve high output voltage using boost technique, leading to a high output power conversion. It has only six external connections with the boost inductance. The input frequency of the bridge rectifier is set at 50 Hz, while the switching frequency is 100 kHz. The proposed circuit is fabricated on a single 0.18-micron CMOS die with a space area of 0.024 mm2. The simulated and measured results show good agreement.

  9. Simultaneous genomic identification and profiling of a single cell using semiconductor-based next generation sequencing

    Directory of Open Access Journals (Sweden)

    Manabu Watanabe

    2014-09-01

    Full Text Available Combining single-cell methods and next-generation sequencing should provide a powerful means to understand single-cell biology and obviate the effects of sample heterogeneity. Here we report a single-cell identification method and seamless cancer gene profiling using semiconductor-based massively parallel sequencing. A549 cells (adenocarcinomic human alveolar basal epithelial cell line were used as a model. Single-cell capture was performed using laser capture microdissection (LCM with an Arcturus® XT system, and a captured single cell and a bulk population of A549 cells (≈106 cells were subjected to whole genome amplification (WGA. For cell identification, a multiplex PCR method (AmpliSeq™ SNP HID panel was used to enrich 136 highly discriminatory SNPs with a genotype concordance probability of 1031–35. For cancer gene profiling, we used mutation profiling that was performed in parallel using a hotspot panel for 50 cancer-related genes. Sequencing was performed using a semiconductor-based bench top sequencer. The distribution of sequence reads for both HID and Cancer panel amplicons was consistent across these samples. For the bulk population of cells, the percentages of sequence covered at coverage of more than 100× were 99.04% for the HID panel and 98.83% for the Cancer panel, while for the single cell percentages of sequence covered at coverage of more than 100× were 55.93% for the HID panel and 65.96% for the Cancer panel. Partial amplification failure or randomly distributed non-amplified regions across samples from single cells during the WGA procedures or random allele drop out probably caused these differences. However, comparative analyses showed that this method successfully discriminated a single A549 cancer cell from a bulk population of A549 cells. Thus, our approach provides a powerful means to overcome tumor sample heterogeneity when searching for somatic mutations.

  10. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    DEFF Research Database (Denmark)

    Ljusev, Petar; Andersen, Michael Andreas E.

    2004-01-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion...

  11. Flux Concentration and Pole Shaping in a Single Phase Hybrid Switched Reluctance Motor Drive

    DEFF Research Database (Denmark)

    Jakobsen, Uffe; Lu, Kaiyuan

    2010-01-01

    The single phase hybrid switched reluctance motor (HSRM) may be a good candidate for low-cost drives used for pump applications. This paper presents a new design of the HSRM with improved starting torque achieved by stator pole shaping, and a better arrangement of the embedded stator permanent...

  12. On-Demand Final State Control of a Surface-Bound Bistable Single Molecule Switch.

    Science.gov (United States)

    Garrido Torres, José A; Simpson, Grant J; Adams, Christopher J; Früchtl, Herbert A; Schaub, Renald

    2018-04-12

    Modern electronic devices perform their defined action because of the complete reliability of their individual active components (transistors, switches, diodes, and so forth). For instance, to encode basic computer units (bits) an electrical switch can be used. The reliability of the switch ensures that the desired outcome (the component's final state, 0 or 1) can be selected with certainty. No practical data storage device would otherwise exist. This reliability criterion will necessarily need to hold true for future molecular electronics to have the opportunity to emerge as a viable miniaturization alternative to our current silicon-based technology. Molecular electronics target the use of single-molecules to perform the actions of individual electronic components. On-demand final state control over a bistable unimolecular component has therefore been one of the main challenges in the past decade (1-5) but has yet to be achieved. In this Letter, we demonstrate how control of the final state of a surface-supported bistable single molecule switch can be realized. On the basis of the observations and deductions presented here, we further suggest an alternative strategy to achieve final state control in unimolecular bistable switches.

  13. Compact frequency-modulation Q-switched single-frequency fiber laser at 1083 nm

    International Nuclear Information System (INIS)

    Zhang, Yuanfei; Feng, Zhouming; Xu, Shanhui; Mo, Shupei; Yang, Changsheng; Li, Can; Gan, Jiulin; Chen, Dongdan; Yang, Zhongmin

    2015-01-01

    A compact frequency-modulation Q-switched single-frequency fiber laser is demonstrated at 1083 nm. The short linear resonant cavity consists of a 12 mm long homemade Yb 3+ -doped phosphate fiber and a pair of fiber Bragg gratings (FBGs) in which the Q-switching and the frequency excursion is achieved by a tensile-induced period modulation. Over 375 MHz frequency-tuning range is achieved with a modulation frequency varying from tens to hundreds of kilohertz. The highest peak power of the output pulse reaching 6.93 W at the repetition rate of 10 kHz is obtained. (paper)

  14. Nanosecond X-ray detector based on high resistivity ZnO single crystal semiconductor

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xiaolong; He, Yongning, E-mail: yongning@mail.xjtu.edu.cn; Peng, Wenbo; Huang, Zhiyong; Qi, Xiaomeng; Pan, Zijian; Zhang, Wenting [School of Electronic and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, Liang; Liu, Jinliang; Zhang, Zhongbing; Ouyang, Xiaoping [Radiation Detection Research Center, Northwest Institute of Nuclear Technology, Xi' an 710024 (China)

    2016-04-25

    The pulse radiation detectors are sorely needed in the fields of nuclear reaction monitoring, material analysis, astronomy study, spacecraft navigation, and space communication. In this work, we demonstrate a nanosecond X-ray detector based on ZnO single crystal semiconductor, which emerges as a promising compound-semiconductor radiation detection material for its high radiation tolerance and advanced large-size bulk crystal growth technique. The resistivity of the ZnO single crystal is as high as 10{sup 13} Ω cm due to the compensation of the donor defects (V{sub O}) and acceptor defects (V{sub Zn} and O{sub i}) after high temperature annealing in oxygen. The photoconductive X-ray detector was fabricated using the high resistivity ZnO single crystal. The rise time and fall time of the detector to a 10 ps pulse electron beam are 0.8 ns and 3.3 ns, respectively, indicating great potential for ultrafast X-ray detection applications.

  15. Calculation of neutron-induced single-event upset cross sections for semiconductor memory devices

    International Nuclear Information System (INIS)

    Ikeuchi, Taketo; Watanabe, Yukinobu; Nakashima, Hideki; Sun, Weili

    2001-01-01

    Neutron-induced single-event upset (SEU) cross sections for semiconductor memory devices are calculated by the Burst Generation Rate (BGR) method using LA150 data and QMD calculation in the neutron energy range between 20 MeV and 10 GeV. The calculated results are compared with the measured SEU cross sections for energies up to 160 MeV, and the validity of the calculation method and the nuclear data used is verified. The kind of reaction products and the neutron energy range that have the most effect on SEU are discussed. (author)

  16. Demultiplexing of OTDM-DPSK signals based on a single semiconductor optical amplifier and optical filtering

    DEFF Research Database (Denmark)

    Xu, Jing; Ding, Yunhong; Peucheret, Christophe

    2011-01-01

    We propose and demonstrate the use of a single semiconductor optical amplifier (SOA) and optical filtering to time demultiplex tributaries from an optical time division multiplexing-differential phase shift keying (OTDM-DPSK) signal. The scheme takes advantage of the fact that phase variations...... added to the target channel by cross-phase modulation from the control signal are effectively subtracted in the differential demodulation scheme employed for DPSK signals. Demultiplexing from 80 to 40 Gbit=s is demonstrated with moderate power penalty using an SOA with recovery time twice as long...

  17. Entangling quantum-logic gate operated with an ultrabright semiconductor single-photon source.

    Science.gov (United States)

    Gazzano, O; Almeida, M P; Nowak, A K; Portalupi, S L; Lemaître, A; Sagnes, I; White, A G; Senellart, P

    2013-06-21

    We demonstrate the unambiguous entangling operation of a photonic quantum-logic gate driven by an ultrabright solid-state single-photon source. Indistinguishable single photons emitted by a single semiconductor quantum dot in a micropillar optical cavity are used as target and control qubits. For a source brightness of 0.56 photons per pulse, the measured truth table has an overlap with the ideal case of 68.4±0.5%, increasing to 73.0±1.6% for a source brightness of 0.17 photons per pulse. The gate is entangling: At a source brightness of 0.48, the Bell-state fidelity is above the entangling threshold of 50% and reaches 71.0±3.6% for a source brightness of 0.15.

  18. On-demand semiconductor source of 780-nm single photons with controlled temporal wave packets

    Science.gov (United States)

    Béguin, Lucas; Jahn, Jan-Philipp; Wolters, Janik; Reindl, Marcus; Huo, Yongheng; Trotta, Rinaldo; Rastelli, Armando; Ding, Fei; Schmidt, Oliver G.; Treutlein, Philipp; Warburton, Richard J.

    2018-05-01

    We report on a fast, bandwidth-tunable single-photon source based on an epitaxial GaAs quantum dot. Exploiting spontaneous spin-flip Raman transitions, single photons at 780 nm are generated on demand with tailored temporal profiles of durations exceeding the intrinsic quantum dot lifetime by up to three orders of magnitude. Second-order correlation measurements show a low multiphoton emission probability [g2(0 ) ˜0.10 -0.15 ] at a generation rate up to 10 MHz. We observe Raman photons with linewidths as low as 200 MHz, which is narrow compared to the 1.1-GHz linewidth measured in resonance fluorescence. The generation of such narrow-band single photons with controlled temporal shapes at the rubidium wavelength is a crucial step towards the development of an optimized hybrid semiconductor-atom interface.

  19. Dynamically Switching among Bundled and Single Tickets with Time-Dependent Demand Rates

    Directory of Open Access Journals (Sweden)

    Serhan Duran

    2012-01-01

    Full Text Available The most important market segmentation in sports and entertainment industry is the competition between customers that buy bundled and single tickets. A common selling practice is starting the selling season with bundled ticket sales and switching to selling single tickets later on. The aim of this practice is to increase the number of customers that buy bundles, which in return increases the load factor of the events with low demand. In this paper, we investigate the effect of time dependent demand on dynamic switching times from bundled to single ticket sales and the potential revenue gain over the case where the demand rate of events is assumed to be constant with time.

  20. Semi-conductor switches

    International Nuclear Information System (INIS)

    1981-01-01

    Methods are described of improving certain electrical characteristics of bidirectional thyristors by selective irradiation of the boundary region between current-carrying portions of the device. Irradiation, preferably by electrons but also by neutrons, gamma radiation or protons, causes carrier lifetime reducing lattice defects. (U.K.)

  1. Research Update: Molecular electronics: The single-molecule switch and transistor

    Directory of Open Access Journals (Sweden)

    Kai Sotthewes

    2014-01-01

    Full Text Available In order to design and realize single-molecule devices it is essential to have a good understanding of the properties of an individual molecule. For electronic applications, the most important property of a molecule is its conductance. Here we show how a single octanethiol molecule can be connected to macroscopic leads and how the transport properties of the molecule can be measured. Based on this knowledge we have realized two single-molecule devices: a molecular switch and a molecular transistor. The switch can be opened and closed at will by carefully adjusting the separation between the electrical contacts and the voltage drop across the contacts. This single-molecular switch operates in a broad temperature range from cryogenic temperatures all the way up to room temperature. Via mechanical gating, i.e., compressing or stretching of the octanethiol molecule, by varying the contact's interspace, we are able to systematically adjust the conductance of the electrode-octanethiol-electrode junction. This two-terminal single-molecule transistor is very robust, but the amplification factor is rather limited.

  2. Density functional theory study of bulk and single-layer magnetic semiconductor CrPS4

    Science.gov (United States)

    Zhuang, Houlong L.; Zhou, Jia

    2016-11-01

    Searching for two-dimensional (2D) materials with multifunctionality is one of the main goals of current research in 2D materials. Magnetism and semiconducting are certainly two desirable functional properties for a single 2D material. In line with this goal, here we report a density functional theory (DFT) study of bulk and single-layer magnetic semiconductor CrPS4. We find that the ground-state magnetic structure of bulk CrPS4 exhibits the A-type antiferromagnetic ordering, which transforms to ferromagnetic (FM) ordering in single-layer CrPS4. The calculated formation energy and phonon spectrum confirm the stability of single-layer CrPS4. The band gaps of FM single-layer CrPS4 calculated with a hybrid density functional are within the visible-light range. We also study the effects of FM ordering on the optical absorption spectra and band alignments for water splitting, indicating that single-layer CrPS4 could be a potential photocatalyst. Our work opens up ample opportunities of energy-related applications of single-layer CrPS4.

  3. Terahertz tunable detection in self-switching diodes based on high mobility semiconductors: InGaAs, InAs and InSb

    International Nuclear Information System (INIS)

    Iniguez-de-la-Torre, I; Rodilla, H; Mateos, J; Pardo, D; Gonzalez, T; Song, A M

    2009-01-01

    In this work we report on the use of high mobility materials in the channel of self-switching diodes as potential candidates for terahertz operation. By means of Monte Carlo simulations we envisage the feasibility of tuneable-by-geometry detection in the terahertz range. The low effective mass of InAs and InSb in relation to InGaAs enhances ballistic transport inside the diode, thus improving the amplitude and quality factor of the resonance found in the detection spectra of self-switching diodes. The frequency of the resonant peak is also increased with the use of these narrow band gap semiconductors. The analysis of the noise spectra provides useful information about the origin of the resonance. By decreasing temperature below 300 K, a clear improvement in detection sensitivity is also achieved.

  4. Terahertz tunable detection in self-switching diodes based on high mobility semiconductors: InGaAs, InAs and InSb

    Energy Technology Data Exchange (ETDEWEB)

    Iniguez-de-la-Torre, I; Rodilla, H; Mateos, J; Pardo, D; Gonzalez, T [Departamento de Fisica Aplicada, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Song, A M, E-mail: indy@usal.e [School of Electrical and Electronic Engineering, University of Manchester, Manchester M60 1QD (United Kingdom)

    2009-11-15

    In this work we report on the use of high mobility materials in the channel of self-switching diodes as potential candidates for terahertz operation. By means of Monte Carlo simulations we envisage the feasibility of tuneable-by-geometry detection in the terahertz range. The low effective mass of InAs and InSb in relation to InGaAs enhances ballistic transport inside the diode, thus improving the amplitude and quality factor of the resonance found in the detection spectra of self-switching diodes. The frequency of the resonant peak is also increased with the use of these narrow band gap semiconductors. The analysis of the noise spectra provides useful information about the origin of the resonance. By decreasing temperature below 300 K, a clear improvement in detection sensitivity is also achieved.

  5. Single-Molecule Photocurrent at a Metal-Molecule-Semiconductor Junction.

    Science.gov (United States)

    Vezzoli, Andrea; Brooke, Richard J; Higgins, Simon J; Schwarzacher, Walther; Nichols, Richard J

    2017-11-08

    We demonstrate here a new concept for a metal-molecule-semiconductor nanodevice employing Au and GaAs contacts that acts as a photodiode. Current-voltage traces for such junctions are recorded using a STM, and the "blinking" or "I(t)" method is used to record electrical behavior at the single-molecule level in the dark and under illumination, with both low and highly doped GaAs samples and with two different types of molecular bridge: nonconjugated pentanedithiol and the more conjugated 1,4-phenylene(dimethanethiol). Junctions with highly doped GaAs show poor rectification in the dark and a low photocurrent, while junctions with low doped GaAs show particularly high rectification ratios in the dark (>10 3 for a 1.5 V bias potential) and a high photocurrent in reverse bias. In low doped GaAs, the greater thickness of the depletion layer not only reduces the reverse bias leakage current, but also increases the volume that contributes to the photocurrent, an effect amplified by the point contact geometry of the junction. Furthermore, since photogenerated holes tunnel to the metal electrode assisted by the HOMO of the molecular bridge, the choice of the latter has a strong influence on both the steady state and transient metal-molecule-semiconductor photodiode response. The control of junction current via photogenerated charge carriers adds new functionality to single-molecule nanodevices.

  6. Advanced single-wafer sequential multiprocessing techniques for semiconductor device fabrication

    International Nuclear Information System (INIS)

    Moslehi, M.M.; Davis, C.

    1989-01-01

    Single-wafer integrated in-situ multiprocessing (SWIM) is recognized as the future trend for advanced microelectronics production in flexible fast turn- around computer-integrated semiconductor manufacturing environments. The SWIM equipment technology and processing methodology offer enhanced equipment utilization, improved process reproducibility and yield, and reduced chip manufacturing cost. They also provide significant capabilities for fabrication of new and improved device structures. This paper describes the SWIM techniques and presents a novel single-wafer advanced vacuum multiprocessing technology developed based on the use of multiple process energy/activation sources (lamp heating and remote microwave plasma) for multilayer epitaxial and polycrystalline semiconductor as well as dielectric film processing. Based on this technology, multilayer in-situ-doped homoepitaxial silicon and heteroepitaxial strained layer Si/Ge x Si 1 - x /Si structures have been grown and characterized. The process control and the ultimate interfacial abruptness of the layer-to-layer transition widths in the device structures prepared by this technology will challenge the MBE techniques in multilayer epitaxial growth applications

  7. Switching behavior of double-decker single molecule magnets on a metal surface

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Yingshuang; Schwoebel, Joerg; Hoffmann, Germar; Brede, Jens; Wiesendanger, Roland [University of Hamburg, Hamburg (Germany); Dillulo, Andrew [Ohio University, Athens (United States); Klyatskaya, Svetlana [Karlsruhe Institute of Technology, Karlsruhe (Germany); Ruben, Mario [Karlsruhe Institute of Technology, Karlsruhe (Germany); Universite de Strasbourg, Strasbourg (France)

    2011-07-01

    Single molecule magnets (SMM) are most promising materials for spin based molecular electronics. Due to their large magnetic anisotropy stabilized by inside chemical bonds, SMM can potentially be used for information storage at the single molecule level. For applications, it is of importance to adsorb the SMM onto surfaces and to study their subsequent conformational, electronic and magnetic properties. We have investigated the adsorption behavior of Tb and Dy based double-decker SMM on an Ir(111) surface with low temperature scanning tunneling microscopy and spectroscopy. It is found that Tb double-decker molecules bind tightly to the Ir(111) surface. By resonantly injecting tunneling electrons into its LUMO or HOMO state, the Tb double-decker molecule can be switched from a four-lobed structure to an eight-lobed structure. After switching, energy positions of the HOMO and LUMO states both shift closer to the Fermi level. Dy double-decker molecules also exhibit the same switching properties on the Ir(111) surface. The switching behavior of the molecules is tentatively attributed to a conformational change of the double-decker molecular frame.

  8. Approaches to building single-stage AC/AC conversion switch-mode audio power amplifiers

    Energy Technology Data Exchange (ETDEWEB)

    Ljusev, P.; Andersen, Michael A.E.

    2005-07-01

    This paper discusses the possible topologies and promising approaches towards direct single-phase AC-AC conversion of the mains voltage for audio applications. When compared to standard Class-D switching audio power amplifiers with a separate power supply, it is expected that direct conversion will provide better efficiency and higher level of integration, leading to lower component count, volume and cost, but at the expense of a minor performance deterioration. (au)

  9. Advanteges of using Two-Switch Forward in Single-Stage Power Factor Corrected Power Supplies

    DEFF Research Database (Denmark)

    Petersen, Lars

    2000-01-01

    A single-Stage power factor corrected power supply using a two-switch forward is proposed to increase efficiency. The converter is operated in the DCM (Discontinues Conduction Mode). This will insure the intermediate DC-bus to be controlled only by means of circuit parameters and therefore...... power supply has been implemented. The measured efficiency and power factor are about 87% and 0.96 respectively....

  10. Magnetic Switching of a Single Molecular Magnet due to Spin-Polarized Current

    OpenAIRE

    Misiorny, Maciej; Barnas, Józef

    2006-01-01

    Magnetic switching of a single molecular magnet (SMM) due to spin-polarized current flowing between ferromagnetic metallic electrodes is investigated theoretically. Magnetic moments of the electrodes are assumed to be collinear and parallel to the magnetic easy axis of the molecule. Electrons tunneling through a barrier between magnetic leads are coupled to the SMM via exchange interaction. The current flowing through the system as well as the spin relaxation times of the SMM are calculated f...

  11. Resistive switching behavior in single crystal SrTiO{sub 3} annealed by laser

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Xinqiang [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Shuai, Yao, E-mail: yshuai@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Collaboration Innovation Center of Electronic Materials and Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Wu, Chuangui, E-mail: cgwu@uestc.edu.cn [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Collaboration Innovation Center of Electronic Materials and Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Luo, Wenbo [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Collaboration Innovation Center of Electronic Materials and Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Sun, Xiangyu [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Yuan, Ye; Zhou, Shengqiang [Helmholtz-Zentrum Dresden Rossendorf, Institute of Ion Beam Physics and Materials Research, Bautzner Landstrasse 400, D-01328 Dresden (Germany); Ou, Xin [State Key Laboratory of Functional Material for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050 (China); Zhang, Wanli [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China); Collaboration Innovation Center of Electronic Materials and Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2016-12-15

    Highlights: • Laser annealing was used to introduce oxygen vacancies into the single crystal SrTiO{sub 3}. • The effect of laser annealing with different fluence on the single crystal SrTiO{sub 3} was systematically studied. • The concentration of oxygen vacancies can be tuned by changing the fluence of laser. • Resistive switching behavior was observed in the sample with relatively high laser fluence after an electro-forming process. - Abstract: Single crystal SrTiO{sub 3} (STO) wafers were annealed by XeCl laser (λ = 308 nm) with different fluences of 0.4 J/cm{sup 2}, 0.6 J/cm{sup 2} and 0.8 J/cm{sup 2}, respectively. Ti/Pt electrodes were sputtered on the surface of STO wafer to form co-planar capacitor-like structures of Pt/Ti/STO/Ti/Pt. Current-Voltage measurements show that the leakage current is enhanced by increasing laser fluence. Resistive switching behavior is only observed in the sample annealed by laser with relatively high fluence after an electro-forming process. The X-ray photoelectron spectroscopy measurements indicate that the amount of oxygen vacancies increases with the increase of laser fluence. This work indicates resistive switching appears when enough oxygen vacancies are generated by the laser, which form conductive filaments under an external electric field.

  12. Magnetotransport investigations of single- and heterostructure epitaxial films of IV/VI-semiconductors

    International Nuclear Information System (INIS)

    Ambrosch, K.-E.

    1985-01-01

    Lead salts are small gap semiconductors that are used for infrared detectors and lasers. PbMnTe and PbEuTe are semimagnetic semiconductors. Magnetotransport properties of epitaxial films and epitaxial heterostructures (PbTe / PbSnTe) are investigated. Epitaxial films of PbSnTe, PbMnTe and PbEuTe have been used for Shubnikov de Haas - experiments in tilted magnetic fields. This method allows the quantitative determination of the electric carrier distribution with respect to the crystal directions. The nonequal distribution is caused by strain effects that are more important for PbMnTe than for PbSnTe and PbEuTe. Magnetoresistance experiments show a deviation from cubic symmetry that leads to the same results for the carrier distribution as the Shubnikov de Haas effect. Magnetoresistance experiments performed with PbTe / PbSnTe heterostructures show no megnetoresistance if the magnetic field is in plane with the layers. The difference of the magnetoresistance for single films and heterostructures is explained by 'quasitwodimensional' carriers. Shubnikov de Haas experiments performed on heterostructures as a function of the tilt angle of the magnetic field show different behaviour compared to that of single films. Using additional information about effective masses and strain it was possible to distinguish between 'two-' and 'threedimensional' electronic systems. The distribution of carriers in single films and heterostructures has been determined by means of magnetotransport experiments. The results are explained by strain effects of the crystal lattice. In addition heterostructures show a 'quasitwodimensional' behaviour caused by interaction of their layers. (Author)

  13. pn junctions based on a single transparent perovskite semiconductor BaSnO3

    Science.gov (United States)

    Kim, Hoon Min; Kim, Useong; Park, Chulkwon; Kwon, Hyukwoo; Lee, Woongjae; Kim, Tai Hoon; Kim, Kee Hoon; Char, Kookrin; Mdpl, Department Of Physics; Astronomy Team; Censcmr, Department Of Physics; Astronomy Team

    2014-03-01

    Successful p doping of transparent oxide semiconductor will further increase its potential, especially in the area of optoelectronic applications. We will report our efforts to dope the BaSnO3 (BSO) with K by pulsed laser deposition. Although the K doped BSO exhibits rather high resistivity at room temperature, its conductivity increases dramatically at higher temperatures. Furthermore, the conductivity decreases when a small amount of oxygen was removed from the film, consistent with the behavior of p type doped oxides. We have fabricated pn junctions by using K doped BSO as a p type and La doped BSO as an n type material. I_V characteristics of these devices show the typical rectifying behavior of pn junctions. We will present the analysis of the junction properties from the temperature dependent measurement of their electrical properties, which shows that the I_V characteristics are consistent with the material parameters such as the carrier concentration, the mobility, and the bandgap. Our demonstration of pn junctions based on a single transparent perovskite semiconductor further enhances the potential of BSO system with high mobility and stability.

  14. Single-Phase Hybrid Switched Reluctance Motor for Low-Power Low-Cost Applications

    DEFF Research Database (Denmark)

    Lu, Kaiyuan; Rasmussen, Peter Omand; Jakobsen, Uffe

    2011-01-01

    This paper presents a new single-phase, Hybrid Switched Reluctance (HSR) motor for low-cost, low-power, pump or fan drive systems. Its single-phase configuration allows use of a simple converter to reduce the system cost. Cheap ferrite magnets are used and arranged in a special flux concentration...... manner to increase effectively the torque density and efficiency of this machine. The efficiency of this machine is comparable to the efficiency of a traditional permanent magnet machine in the similar power range. The cogging torque, due to the existence of the permanent magnetic field, is beneficially...

  15. On-demand semiconductor single-photon source with near-unity indistinguishability.

    Science.gov (United States)

    He, Yu-Ming; He, Yu; Wei, Yu-Jia; Wu, Dian; Atatüre, Mete; Schneider, Christian; Höfling, Sven; Kamp, Martin; Lu, Chao-Yang; Pan, Jian-Wei

    2013-03-01

    Single-photon sources based on semiconductor quantum dots offer distinct advantages for quantum information, including a scalable solid-state platform, ultrabrightness and interconnectivity with matter qubits. A key prerequisite for their use in optical quantum computing and solid-state networks is a high level of efficiency and indistinguishability. Pulsed resonance fluorescence has been anticipated as the optimum condition for the deterministic generation of high-quality photons with vanishing effects of dephasing. Here, we generate pulsed single photons on demand from a single, microcavity-embedded quantum dot under s-shell excitation with 3 ps laser pulses. The π pulse-excited resonance-fluorescence photons have less than 0.3% background contribution and a vanishing two-photon emission probability. Non-postselective Hong-Ou-Mandel interference between two successively emitted photons is observed with a visibility of 0.97(2), comparable to trapped atoms and ions. Two single photons are further used to implement a high-fidelity quantum controlled-NOT gate.

  16. Properties of a GaAs Single Electron Path Switching Node Device Using a Single Quantum Dot for Hexagonal BDD Quantum Circuits

    International Nuclear Information System (INIS)

    Nakamura, Tatsuya; Abe, Yuji; Kasai, Seiya; Hasegawa, Hideki; Hashizume, Tamotsu

    2006-01-01

    A new single electron (SE) binary-decision diagram (BDD) node device having a single quantum dot connected to three nanowire branches through tunnel barriers was fabricated using etched AlGaAs/GaAs nanowires and nanometer-sized Schottky wrap gates (WPGs), and their operation was characterized experimentally, for the hexagonal BDD quantum circuit. Fabricated devices showed clear and steep single electron pass switching by applying only an input voltage signal, which was completely different from switching properties in the previous SE BDD node devices composed of two single electron switches. As the possible switching mechanism, the correlation between the probabilities of tunnelling thorough a single quantum dot in exit branches was discussed

  17. Anisotropic exchange interaction induced by a single photon in semiconductor microcavities

    Science.gov (United States)

    Chiappe, G.; Fernández-Rossier, J.; Louis, E.; Anda, E. V.

    2005-12-01

    We investigate coupling of localized spins in a semiconductor quantum dot embedded in a microcavity. The lowest cavity mode and the quantum dot exciton are coupled and close in energy, forming a polariton. The fermions forming the exciton interact with localized spins via exchange. Exact diagonalization of a Hamiltonian in which photons, spins, and excitons are treated quantum mechanically shows that a single polariton induces a sizable indirect anisotropic exchange interaction between spins. At sufficiently low temperatures strong ferromagnetic correlations show up without an appreciable increase in exciton population. In the case of a (Cd,Mn)Te quantum dot, Mn-Mn ferromagnetic coupling is still significant at 1 K : spin-spin correlation around 3 for exciton occupation smaller than 0.3. We find that the interaction mediated by photon-polaritons is 10 times stronger than the one induced by a classical field for equal Rabi splitting.

  18. Field emission mechanism from a single-layer ultra-thin semiconductor film cathode

    International Nuclear Information System (INIS)

    Duan Zhiqiang; Wang Ruzhi; Yuan Ruiyang; Yang Wei; Wang Bo; Yan Hui

    2007-01-01

    Field emission (FE) from a single-layer ultra-thin semiconductor film cathode (SUSC) on a metal substrate has been investigated theoretically. The self-consistent quantum FE model is developed by synthetically considering the energy band bending and electron scattering. As a typical example, we calculate the FE properties of ultra-thin AlN film with an adjustable film thickness from 1 to 10 nm. The calculated results show that the FE characteristic is evidently modulated by varying the film thickness, and there is an optimum thickness of about 3 nm. Furthermore, a four-step FE mechanism is suggested such that the distinct FE current of a SUSC is rooted in the thickness sensitivity of its quantum structure, and the optimum FE properties of the SUSC should be attributed to the change in the effective potential combined with the attenuation of electron scattering

  19. Bipolar resistive switching of single gold-in-Ga2O3 nanowire.

    Science.gov (United States)

    Hsu, Chia-Wei; Chou, Li-Jen

    2012-08-08

    We have fabricated single nanowire chips on gold-in-Ga(2)O(3) core-shell nanowires using the electron-beam lithography techniques and realized bipolar resistive switching characteristics having invariable set and reset voltages. We attribute the unique property of invariance to the built-in conduction path of gold core. This invariance allows us to fabricate many resistive switching cells with the same operating voltage by simple depositing repetitive metal electrodes along a single nanowire. Other characteristics of these core-shell resistive switching nanowires include comparable driving electric field with other thin film and nanowire devices and a remarkable on/off ratio more than 3 orders of magnitude at a low driving voltage of 2 V. A smaller but still impressive on/off ratio of 10 can be obtained at an even lower bias of 0.2 V. These characteristics of gold-in-Ga(2)O(3) core-shell nanowires make fabrication of future high-density resistive memory devices possible.

  20. Temperature induced Spin Switching in SmFeO3 Single Crystal

    Science.gov (United States)

    Cao, Shixun; Zhao, Huazhi; Kang, Baojuan; Zhang, Jincang; Ren, Wei

    2014-08-01

    The prospect of controlling the magnetization (M) of a material is of great importance from the viewpoints of fundamental physics and future applications of emerging spintronics. A class of rare-earth orthoferrites RFeO3 (R is rare-earth element) materials exhibit striking physical properties of spin switching and magnetization reversal induced by temperature and/or applied magnetic field. Furthermore, due to the novel magnetic, magneto-optic and multiferroic properties etc., RFeO3 materials are attracting more and more interests in recent years. We have prepared and investigated a prototype of RFeO3 materials, namely SmFeO3 single-crystal. And we report magnetic measurements upon both field cooling (FC) and zero-field cooling (ZFC) of the sample, as a function of temperature and applied magnetic field. The central findings of this study include that the magnetization of single-crystal SmFeO3 can be switched by temperature, and tuning the magnitude of applied magnetic field allows us to realize such spin switching even at room temperature.

  1. Silicon photonics WDM transmitter with single section semiconductor mode-locked laser

    Science.gov (United States)

    Müller, Juliana; Hauck, Johannes; Shen, Bin; Romero-García, Sebastian; Islamova, Elmira; Azadeh, Saeed Sharif; Joshi, Siddharth; Chimot, Nicolas; Moscoso-Mártir, Alvaro; Merget, Florian; Lelarge, François; Witzens, Jeremy

    2015-04-01

    We demonstrate a wavelength domain-multiplexed (WDM) optical link relying on a single section semiconductor mode-locked laser (SS-MLL) with quantum dash (Q-Dash) gain material to generate 25 optical carriers spaced by 60.8 GHz, as well as silicon photonics (SiP) resonant ring modulators (RRMs) to modulate individual optical channels. The link requires optical reamplification provided by an erbium-doped fiber amplifier (EDFA) in the system experiments reported here. Open eye diagrams with signal quality factors (Q-factors) above 7 are measured with a commercial receiver (Rx). For higher compactness and cost effectiveness, reamplification of the modulated channels with a semiconductor optical amplifier (SOA) operated in the linear regime is highly desirable. System and device characterization indicate compatibility with the latter. While we expect channel counts to be primarily limited by the saturation output power level of the SOA, we estimate a single SOA to support more than eight channels. Prior to describing the system experiments, component design and detailed characterization results are reported including design and characterization of RRMs, ring-based resonant optical add-drop multiplexers (RR-OADMs) and thermal tuners, S-parameters resulting from the interoperation of RRMs and RR-OADMs, and characterization of Q-Dash SS-MLLs reamplified with a commercial SOA. Particular emphasis is placed on peaking effects in the transfer functions of RRMs and RR-OADMs resulting from transient effects in the optical domain, as well as on the characterization of SS-MLLs in regard to relative intensity noise (RIN), stability of the modes of operation, and excess noise after reamplification.

  2. Stereoelectronic Effect-Induced Conductance Switching in Aromatic Chain Single-Molecule Junctions.

    Science.gov (United States)

    Xin, Na; Wang, Jinying; Jia, Chuancheng; Liu, Zitong; Zhang, Xisha; Yu, Chenmin; Li, Mingliang; Wang, Shuopei; Gong, Yao; Sun, Hantao; Zhang, Guanxin; Liu, Zhirong; Zhang, Guangyu; Liao, Jianhui; Zhang, Deqing; Guo, Xuefeng

    2017-02-08

    Biphenyl, as the elementary unit of organic functional materials, has been widely used in electronic and optoelectronic devices. However, over decades little has been fundamentally understood regarding how the intramolecular conformation of biphenyl dynamically affects its transport properties at the single-molecule level. Here, we establish the stereoelectronic effect of biphenyl on its electrical conductance based on the platform of graphene-molecule single-molecule junctions, where a specifically designed hexaphenyl aromatic chain molecule is covalently sandwiched between nanogapped graphene point contacts to create stable single-molecule junctions. Both theoretical and temperature-dependent experimental results consistently demonstrate that phenyl twisting in the aromatic chain molecule produces different microstates with different degrees of conjugation, thus leading to stochastic switching between high- and low-conductance states. These investigations offer new molecular design insights into building functional single-molecule electrical devices.

  3. Mid-infrared Fe2+:ZnSe semiconductor saturable absorber mirror for passively Q-switched Er3+-doped ZBLAN fiber laser

    Directory of Open Access Journals (Sweden)

    Shougui Ning

    2018-02-01

    Full Text Available A mid-infrared (mid-IR semiconductor saturable absorber mirror (SESAM based on Fe2+:ZnSe for passively Q-switched Er3+-doped ZBLAN fiber laser has been demonstrated. Fe2+:ZnSe SESAM was fabricated by electron beam evaporation method. Fe2+ was innovatively doped into the reflective Bragg stack, in which ZnSe layer served as both doped matrix and high refractive layer during the fabricating process. By using the Fe2+:ZnSe SESAM, stable passively Q-switched pulses with the minimum pulse width of 0.43 μs under a repetition rate of 160.82 kHz were obtained. The recorded maximum average output power of 873 mW with a peak power of 12.59 W and pulse energy of 5.43 μJ were achieved. The results demonstrated a new method for fabricating Fe2+:ZnSe SESAM, which can be used in compact mid-IR Q-switched fiber laser.

  4. Lower Side Switching Modification of SHEPWM for Single H-Bridge Unipolar Inverter

    Science.gov (United States)

    Aihsan, M. Z.

    2018-03-01

    Selective Harmonic Elimination Pulse Width Modulation (SHEPWM) is a famous fundamental frequency method for both single stage H-bridge inverter and cascaded multilevel inverters. The main function of SHEPWM is to eliminate the selective lower order of odd harmonic such 3rd, 5th 7th and 9th of the output voltage of the inverter but maintain the fundamental component. In this paper, the 5kHz of the unipolar SHEPWM switching scheme of the inverter is developed and later will be compared to the modified SHEPWM switching scheme. The performance of this inverter is measured through the final total harmonic distortion (THD), the efficiency of the whole system and the natural shape of the output after LC filter.

  5. Magnetic switching of a single molecular magnet due to spin-polarized current

    Science.gov (United States)

    Misiorny, Maciej; Barnaś, Józef

    2007-04-01

    Magnetic switching of a single molecular magnet (SMM) due to spin-polarized current flowing between ferromagnetic metallic leads (electrodes) is investigated theoretically. Magnetic moments of the leads are assumed to be collinear and parallel to the magnetic easy axis of the molecule. Electrons tunneling through the barrier between magnetic leads are coupled to the SMM via exchange interaction. The current flowing through the system, as well as the spin relaxation times of the SMM, are calculated from the Fermi golden rule. It is shown that spin of the SMM can be reversed by applying a certain voltage between the two magnetic electrodes. Moreover, the switching may be visible in the corresponding current-voltage characteristics.

  6. High Isolation Single-Pole Four-Throw RF MEMS Switch Based on Series-Shunt Configuration

    Directory of Open Access Journals (Sweden)

    Tejinder Singh

    2014-01-01

    Full Text Available This paper presents a novel design of single-pole four-throw (SP4T RF-MEMS switch employing both capacitive and ohmic switches. It is designed on high-resistivity silicon substrate and has a compact area of 1.06 mm2. The series or ohmic switches have been designed to provide low insertion loss with good ohmic contact. The pull-in voltage for ohmic switches is calculated to be 7.19 V. Shunt or capacitive switches have been used in each port to improve the isolation for higher frequencies. The proposed SP4T switch provides excellent RF performances with isolation better than 70.64 dB and insertion loss less than 0.72 dB for X-band between the input port and each output port.

  7. Self-Aligned Growth of Organic Semiconductor Single Crystals by Electric Field.

    Science.gov (United States)

    Kotsuki, Kenji; Obata, Seiji; Saiki, Koichiro

    2016-01-19

    We proposed a novel but facile method for growing organic semiconductor single-crystals via solvent vapor annealing (SVA) under electric field. In the conventional SVA growth process, nuclei of crystals appeared anywhere on the substrate and their crystallographic axes were randomly distributed. We applied electric field during the SVA growth of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) on the SiO2/Si substrate on which a pair of electrodes had been deposited beforehand. Real-time observation of the SVA process revealed that rodlike single crystals grew with their long axes parallel to the electric field and bridged the prepatterned electrodes. As a result, C8-BTBT crystals automatically formed a field effect transistor (FET) structure and the mobility reached 1.9 cm(2)/(V s). Electric-field-assisted SVA proved a promising method for constructing high-mobility single-crystal FETs at the desired position by a low-cost solution process.

  8. Simple Atomic Quantum Memory Suitable for Semiconductor Quantum Dot Single Photons

    Science.gov (United States)

    Wolters, Janik; Buser, Gianni; Horsley, Andrew; Béguin, Lucas; Jöckel, Andreas; Jahn, Jan-Philipp; Warburton, Richard J.; Treutlein, Philipp

    2017-08-01

    Quantum memories matched to single photon sources will form an important cornerstone of future quantum network technology. We demonstrate such a memory in warm Rb vapor with on-demand storage and retrieval, based on electromagnetically induced transparency. With an acceptance bandwidth of δ f =0.66 GHz , the memory is suitable for single photons emitted by semiconductor quantum dots. In this regime, vapor cell memories offer an excellent compromise between storage efficiency, storage time, noise level, and experimental complexity, and atomic collisions have negligible influence on the optical coherences. Operation of the memory is demonstrated using attenuated laser pulses on the single photon level. For a 50 ns storage time, we measure ηe2 e 50 ns=3.4 (3 )% end-to-end efficiency of the fiber-coupled memory, with a total intrinsic efficiency ηint=17 (3 )%. Straightforward technological improvements can boost the end-to-end-efficiency to ηe 2 e≈35 %; beyond that, increasing the optical depth and exploiting the Zeeman substructure of the atoms will allow such a memory to approach near unity efficiency. In the present memory, the unconditional read-out noise level of 9 ×10-3 photons is dominated by atomic fluorescence, and for input pulses containing on average μ1=0.27 (4 ) photons, the signal to noise level would be unity.

  9. Single pole rapid reclosing: effective damping of ehv switching surges through discharge resistors

    Energy Technology Data Exchange (ETDEWEB)

    Heinemann, T

    1965-04-30

    The stability of interconnecting circuits is very important and loss of synchronism of a complete network due to a temporary single-phase fault is operationally and economically undesirable. The use of grounding resistors together with load-break isolators which can be electrically or mechanically coupled to the circuit-breakers yield interesting possibilities in extra-high-voltage networks. The three problems, i.e., discharging of charged lines, damping of switching surges, and single-pole rapid-reclosing, can be solved through the use of a number of similar resistors and load-break isolators connected in series according to the voltage. The thermal and electrical stresses of the resistors can be kept within permissible limits. The time required for arc extinction and the limits in respect of length of lines will have to be determined by actual tests. For single-pole rapid-reclosing during a single-phase earth fault the switching operations on both sides of the line must be simultaneous. Because of the very small divergence of the opening and making times of modern circuit-breakers it will be sufficient only to synchronise the operating impulse.

  10. Six switches solution for single-phase AC/DC/AC converter with capability of second-order power mitigation in DC-link capacitor

    DEFF Research Database (Denmark)

    Liu, Xiong; Wang, Peng; Loh, Poh Chiang

    2011-01-01

    This paper proposes an approach for DC-link second-order harmonic power cancellation in single-phase AC/DC/AC converter with reduced number of switches. The proposed six-switch converter has two bridges with three switches in each of them, where the middle switch in each bridge is shared by the A...

  11. Thin film complementary metal oxide semiconductor (CMOS) device using a single-step deposition of the channel layer

    KAUST Repository

    Nayak, Pradipta K.; Caraveo-Frescas, J. A.; Wang, Zhenwei; Hedhili, Mohamed N.; Wang, Q. X.; Alshareef, Husam N.

    2014-01-01

    We report, for the first time, the use of a single step deposition of semiconductor channel layer to simultaneously achieve both n-and p-type transport in transparent oxide thin film transistors (TFTs). This effect is achieved by controlling

  12. Self-phase modulation of a single-cycle terahertz pulse by nonlinear free-carrier response in a semiconductor

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.

    2012-01-01

    We investigate the self-phase modulation (SPM) of a single-cycle terahertz pulse in a semiconductor, using bulk n-GaAs as a model system. The SPM arises from the heating of free electrons in the electric field of the terahertz pulse, leading to an ultrafast reduction of the plasma frequency...

  13. Single-step solution processing of small-molecule organic semiconductor field-effect transistors at high yield

    NARCIS (Netherlands)

    Yu, Liyang; Li, X.; Pavlica, E.; Loth, M.A.; Anthony, J.E.; Bratina, G.; Kjellander, B.K.C.; Gelinck, G.H.; Stutzmann, N.

    2011-01-01

    Here, we report a simple, alternative route towards high-mobility structures of the small-molecular semiconductor 5,11-bis(triethyl silylethynyl) anthradithiophene that requires one single processing step without the need for any post-deposition processing. The method relies on careful control of

  14. Collection-limited theory interprets the extraordinary response of single semiconductor organic solar cells

    Science.gov (United States)

    Ray, Biswajit; Baradwaj, Aditya G.; Khan, Mohammad Ryyan; Boudouris, Bryan W.; Alam, Muhammad Ashraful

    2015-01-01

    The bulk heterojunction (BHJ) organic photovoltaic (OPV) architecture has dominated the literature due to its ability to be implemented in devices with relatively high efficiency values. However, a simpler device architecture based on a single organic semiconductor (SS-OPV) offers several advantages: it obviates the need to control the highly system-dependent nanoscale BHJ morphology, and therefore, would allow the use of broader range of organic semiconductors. Unfortunately, the photocurrent in standard SS-OPV devices is typically very low, which generally is attributed to inefficient charge separation of the photogenerated excitons. Here we show that the short-circuit current density from SS-OPV devices can be enhanced significantly (∼100-fold) through the use of inverted device configurations, relative to a standard OPV device architecture. This result suggests that charge generation may not be the performance bottleneck in OPV device operation. Instead, poor charge collection, caused by defect-induced electric field screening, is most likely the primary performance bottleneck in regular-geometry SS-OPV cells. We justify this hypothesis by: (i) detailed numerical simulations, (ii) electrical characterization experiments of functional SS-OPV devices using multiple polymers as active layer materials, and (iii) impedance spectroscopy measurements. Furthermore, we show that the collection-limited photocurrent theory consistently interprets typical characteristics of regular SS-OPV devices. These insights should encourage the design and OPV implementation of high-purity, high-mobility polymers, and other soft materials that have shown promise in organic field-effect transistor applications, but have not performed well in BHJ OPV devices, wherein they adopt less-than-ideal nanostructures when blended with electron-accepting materials. PMID:26290582

  15. Parallel superconducting strip-line detectors: reset behaviour in the single-strip switch regime

    International Nuclear Information System (INIS)

    Casaburi, A; Heath, R M; Tanner, M G; Hadfield, R H; Cristiano, R; Ejrnaes, M; Nappi, C

    2014-01-01

    Superconducting strip-line detectors (SSLDs) are an important emerging technology for the detection of single molecules in time-of-flight mass spectrometry (TOF-MS). We present an experimental investigation of a SSLD laid out in a parallel configuration, designed to address selected single strip-lines operating in the single-strip switch regime. Fast laser pulses were tightly focused onto the device, allowing controllable nucleation of a resistive region at a specific location and study of the subsequent device response dynamics. We observed that in this regime, although the strip-line returns to the superconducting state after triggering, no effective recovery of the bias current occurs, in qualitative agreement with a phenomenological circuit simulation that we performed. Moreover, from theoretical considerations and by looking at the experimental pulse amplitude distribution histogram, we have the first confirmation of the fact that the phenomenological London model governs the current redistribution in these large area devices also after detection events. (paper)

  16. Learning and mastery behaviours as risk factors to abandonment in a paediatric user of advanced single-switch access technology.

    Science.gov (United States)

    Brian, Leung; Jessica A, Brian; Tom, Chau

    2013-09-01

    The present descriptive case study documents the behaviours of a child single-switch user in the community setting and draws attention to learning and mastery behaviours as risk factors to single-switch abandonment. Our observations were interpreted in the context of a longer term school-based evaluation of an advanced single-switch access technology with a nine year-old user with severe spastic quadriplegic cerebral palsy. The child completed 25 experiment sessions averaging a rate of three sessions every two weeks. During each session he worked on several blocks of single-switch computer activity using his vocal cord vibration switch. Despite high levels of single-switch sensitivity and specificity that suggested a good fit between the participant and the technology, the participant perceived a lower proficiency level of his own abilities, demonstrated impatience and intolerance to interaction errors, and was apprehensive of making mistakes when using his switch in public. The benefit of gaining some degree of independent physical access might not necessarily enhance resilience to interaction errors or bouts of poor task performance. On the other hand, the participant's behaviours were consistent with those of a typically developing child learning or mastering any new skill or task. Implications for Rehabilitation The attitude and behaviour of a paediatric switch user towards skill development can be risk factors to abandonment of an access technology, despite successful clinical trial with the device. Children with severe disabilities can be associated with the same types of skill development behaviour patterns and achievement motivation as their typically developing peers. Empirical observations of the case participant's switch use behaviours suggest that user training could be adaptive in order to account for individual differences in skill development and achievement motivation.

  17. Current-induced magnetic switching of a single molecule magnet on a spin valve

    International Nuclear Information System (INIS)

    Zhang, Xiao; Wang, Zheng-Chuan; Zheng, Qing-Rong; Zhu, Zheng-Gang; Su, Gang

    2015-01-01

    The current-induced magnetic switching of a single-molecule magnet (SMM) attached on the central region of a spin valve is explored, and the condition for the switching current is derived. Electrons flowing through the spin valve will interact with the SMM via the s–d exchange interaction, producing the spin accumulation that satisfies the spin diffusion equation. We further describe the spin motion of the SMM by a Heisenberg-like equation. Based on the linear stability analysis, we obtain the critical current from two coupled equations. The results of the critical current versus the external magnetic field indicate that one can manipulate the magnetic state of the SMM by an external magnetic field. - Highlights: • We theoretically study the current-induced magnetic switching of the SMM. • We describe the spin motion of the SMM by a Heisenberg-like equation. • We describe the spin accumulation by the spin diffusion equation. • We obtain the critical current by the linear stability analysis. • Our approach can be easily extended to other SMMs

  18. Current-induced magnetic switching of a single molecule magnet on a spin valve

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiao [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Zheng-Chuan, E-mail: wangzc@ucas.ac.cn [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zheng, Qing-Rong [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); Zhu, Zheng-Gang [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China); School of Electronics, Electric and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049 (China); Su, Gang, E-mail: gsu@ucas.ac.cn [Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, School of Physics, University of Chinese Academy of Sciences, Beijing 100049 (China)

    2015-04-17

    The current-induced magnetic switching of a single-molecule magnet (SMM) attached on the central region of a spin valve is explored, and the condition for the switching current is derived. Electrons flowing through the spin valve will interact with the SMM via the s–d exchange interaction, producing the spin accumulation that satisfies the spin diffusion equation. We further describe the spin motion of the SMM by a Heisenberg-like equation. Based on the linear stability analysis, we obtain the critical current from two coupled equations. The results of the critical current versus the external magnetic field indicate that one can manipulate the magnetic state of the SMM by an external magnetic field. - Highlights: • We theoretically study the current-induced magnetic switching of the SMM. • We describe the spin motion of the SMM by a Heisenberg-like equation. • We describe the spin accumulation by the spin diffusion equation. • We obtain the critical current by the linear stability analysis. • Our approach can be easily extended to other SMMs.

  19. Electron tunnelling through single azurin molecules can be on/off switched by voltage pulses

    Energy Technology Data Exchange (ETDEWEB)

    Baldacchini, Chiara [Biophysics and Nanoscience Centre, DEB-CNISM, Università della Tuscia, I-01100 Viterbo (Italy); Institute of Agro-Environmental and Forest Biology, CNR, I-05010 Porano (Italy); Kumar, Vivek; Bizzarri, Anna Rita; Cannistraro, Salvatore, E-mail: cannistr@unitus.it [Biophysics and Nanoscience Centre, DEB-CNISM, Università della Tuscia, I-01100 Viterbo (Italy)

    2015-05-04

    Redox metalloproteins are emerging as promising candidates for future bio-optoelectronic and nano-biomemory devices, and the control of their electron transfer properties through external signals is still a crucial task. Here, we show that a reversible on/off switching of the electron current tunnelling through a single protein can be achieved in azurin protein molecules adsorbed on gold surfaces, by applying appropriate voltage pulses through a scanning tunnelling microscope tip. The observed changes in the hybrid system tunnelling properties are discussed in terms of long-sustained charging of the protein milieu.

  20. Current-Induced Switching of a Single-Molecule Magnet with Arbitrary Oriented Easy Axis

    OpenAIRE

    Misiorny, Maciej; Barnas, Józef

    2007-01-01

    The main objective of this work is to investigate theoretically how tilting of an easy axis of a single-molecule magnet (SMM) from the orientation collinear with magnetic moments of the leads affects the switching process induced by current flowing through the system. To do this we consider a model system that consists of a SMM embedded in the nonmagnetic barrier of a magnetic tunnel junction. The anisotropy axis of the SMM forms an arbitrary angle with magnetic moments of the leads (the latt...

  1. Spectrum sensing using single-radio switched-beam antenna systems

    DEFF Research Database (Denmark)

    Tsakalaki, Elpiniki; Wilcox, David; De Carvalho, Elisabeth

    2012-01-01

    of the reactive loads rotate the narrowband beampattern to different angular positions dividing the whole space around the cognitive receiver into several angular subspaces. The beampattern directionality leverages the performance of spectrum sensing algorithms like the energy detection by enhancing the receive......The paper describes spectrum sensing using single-radio switched-beam arrays with reactance-loaded parasitic elements. At a given frequency, the antenna's loading conditions (reactive loads) are optimized for maximum average beamforming gain in the beampattern look direction. Circular permutations...

  2. hamlet, a binary genetic switch between single- and multiple- dendrite neuron morphology.

    Science.gov (United States)

    Moore, Adrian W; Jan, Lily Yeh; Jan, Yuh Nung

    2002-08-23

    The dendritic morphology of neurons determines the number and type of inputs they receive. In the Drosophila peripheral nervous system (PNS), the external sensory (ES) neurons have a single nonbranched dendrite, whereas the lineally related multidendritic (MD) neurons have extensively branched dendritic arbors. We report that hamlet is a binary genetic switch between these contrasting morphological types. In hamlet mutants, ES neurons are converted to an MD fate, whereas ectopic hamlet expression in MD precursors results in transformation of MD neurons into ES neurons. Moreover, hamlet expression induced in MD neurons undergoing dendrite outgrowth drastically reduces arbor branching.

  3. Polarization Properties of Semiconductor Nanorod Heterostructures: From Single Particles to the Ensemble.

    Science.gov (United States)

    Hadar, Ido; Hitin, Gal B; Sitt, Amit; Faust, Adam; Banin, Uri

    2013-02-07

    Semiconductor heterostructured seeded nanorods exhibit intense polarized emission, and the degree of polarization is determined by their morphology and dimensions. Combined optical and atomic force microscopy were utilized to directly correlate the emission polarization and the orientation of single seeded nanorods. For both the CdSe/CdS sphere-in-rod (S@R) and rod-in-rod (R@R), the emission was found to be polarized along the nanorod's main axis. Statistical analysis for hundreds of single nanorods shows higher degree of polarization, p, for R@R (p = 0.83), in comparison to S@R (p = 0.75). These results are in good agreement with the values inferred by ensemble photoselection anisotropy measurements in solution, establishing its validity for nanorod samples. On this basis, photoselection photoluminescence excitation anisotropy measurements were carried out providing unique information concerning the symmetry of higher excitonic transitions and allowing for a better distinction between the dielectric and the quantum-mechanical contributions to polarization in nanorods.

  4. Conversion from non-orthogonally to orthogonally polarized optical single-sideband modulation using optically injected semiconductor lasers.

    Science.gov (United States)

    Hung, Yu-Han; Tseng, Chin-Hao; Hwang, Sheng-Kwang

    2018-06-01

    This Letter investigates an optically injected semiconductor laser for conversion from non-orthogonally to orthogonally polarized optical single-sideband modulation. The underlying mechanism relies solely on nonlinear laser characteristics and, thus, only a typical semiconductor laser is required as the key conversion unit. This conversion can be achieved for a broadly tunable frequency range up to at least 65 GHz. After conversion, the microwave phase quality, including linewidth and phase noise, is mostly preserved, and simultaneous microwave amplification up to 23 dB is feasible.

  5. Electrical switching phenomenon and memory effect in the semiconductor chalcogenide glass Ge0.10 As0.20 Te0.70

    International Nuclear Information System (INIS)

    Haro, M.; Marquez, E.; Villares, P.; Jimenez-Garay, R.

    1987-01-01

    Electrical switching phenomenon, as well as the memory effect in the semiconductor chalcogenide glass Ge 0.10 As 0.20 Te 0.70 has been studied. A device with a plano-punctual interelectrode configuration has been designed and built, so that the electrical stimuli may be applied correctly. This device permits adequate positioning of the upper electrode, as well as contact pressure regulation. The I-V characteristics in the OFF-state have been obtained, showing a marked non-linear character. Equally, a relation has been found between the threshold voltage and electrical resistance parameters, indicating that the electrical power giving rise to the phenomenon is constant. Finally, memory effects showing a sudden reduction in electrical resistance, as well as interelectrode filaments, have been observed. (author)

  6. Singly-resonant sum frequency generation of visible light in a semiconductor disk laser

    DEFF Research Database (Denmark)

    Andersen, Martin Thalbitzer; Schlosser, P.J.; Hastie, J.E.

    2009-01-01

    In this paper a generic approach for visible light generation is presented. It is based on sum frequency generation between a semiconductor disk laser and a solid-state laser, where the frequency mixing is achieved within the cavity of the semiconductor disk laser using a singlepass of the solid......-state laser light. This exploits the good beam quality and high intra-cavity power present in the semiconductor disk laser to achieve high conversion efficiency. Combining sum frequency mixing and semiconductor disk lasers in this manner allows in principle for generation of any wavelength within the visible...

  7. In-plane magnetic anisotropy and temperature dependence of switching field in (Ga, Mn) as ferromagnetic semiconductors.

    Science.gov (United States)

    Kamara, S; Terki, F; Dumas, R; Dehbaoui, M; Sadowski, J; Galéra, R M; Tran, Q-H; Charar, S

    2012-06-01

    We explore the magnetic anisotropy of GaMnAs ferromagnetic semiconductor by Planar Hall Effect (PHE) measurements. Using low magnitude of applied magnetic field (i.e., when the magnitude H is smaller than both cubic Hc and uniaxial Hu anisotropy field), we have observed various shapes of applied magnetic field direction dependence of Planar Hall Resistance (PHR). In particular, in two regions of temperature. At T Tc/2 the "zigzag-shape" signal of PHR. They reflect different magnetic anisotropy and provide information about magnetization reversal process in GaMnAs ferromagnetic semiconductor. The theoretical model calculation of PHR based on the free energy density reproduces well the experimental data. We report also the temperature dependence of anisotropy constants and magnetization orientations. The transition of easy axis from biaxial to uniaxiale axes has been observed and confirmed by SQUID measurements.

  8. Spectroscopy of size dependent many-particle effects in single self-assembled semiconductor quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Dal Savio, C.

    2006-02-20

    Single InAs quantum dots (QDs) grown with the Stranski-Krastanov method in a In{sub 0.12}Ga{sub 0.88}As quantum well embedded in GaAs and emitting in the near infrared have been optically investigated. To perform QD spectroscopy at low temperatures a very stable micro-photoluminescence ({mu}-PL) microscope set-up fully integrated in a liquid helium (LHe) cryostate has been successfully developed. The system is based on the cold finger technique and a Fourier Transform (FT) spectrometer combined with a nitrogen cooled Ge detector. Photoluminescence of the QDs was excited non resonantly with a He-Ne laser and single dot spectroscopy was carried out at temperatures below 60 K. The experimental set-up allows mapping of the optical emission by recording spectra for every point of a scan grid. This mapping mode is used to acquire optical images and to locate a particular dot for investigation. Series of measurement on a single QD were normally performed over a long time (from a few days to a week), with the need of daily adjustment in the sub-micrometer range. At low excitation power a single sharp line (E{sub x}) arising from recombination of a single exciton in the dot is observed. Varying the excitation density the spectra become more complex, with appearance of the biexciton emission line (E{sub xx}) on the lower energies side of the E{sub x} line, followed by emission from excitons occupying higher shells in the dot. Measured biexciton binding energies and power dependence are in good agreement with values reported in the literature. The temperature dependence of the optical emission was investigated. The energy shows the characteristic decrease related to the shrinking of the semiconductor band gap, while the linewidth evolution is compatible with broadening due to coupling with acoustic and optical phonons. A statistics of biexciton binding energies over a dozen of dots was acquired and the results compared with single QD spectroscopy data available in the

  9. Single Photon Detection with Semiconductor Pixel Arrays for Medical Imaging Applications

    CERN Document Server

    Mikulec, B

    2000-01-01

    This thesis explores the functioning of a single photon counting pixel detector for X-ray imaging. It considers different applications for such a device, but focuses mainly on the field of medical imaging. The new detector comprises a CMOS read-out chip called PCC containing 4096 identical channels each of which counts X-ray hits. The conversion of the X-rays to electric charge takes place in a semiconductor sensor which is segmented into 4096 matching square diodes of side length 170 um, the 'pixels'. The photon counting concept is based on setting a threshold in energy above which a hit is registered. The immediate advantages are the elimination of background and the in principle unlimited dynamic range. Moreover, this approach allows the use of an electronic shutter for arbitrary measurement periods. As the device was intended for operation in the energy range of ~10-70 keV, gallium arsenide was selected as the preferred sensor material. The development of this detector followed on from about 10 years of r...

  10. Semiconductor-Free Nonvolatile Resistive Switching Memory Devices Based on Metal Nanogaps Fabricated on Flexible Substrates via Adhesion Lithography

    KAUST Repository

    Semple, James

    2017-01-02

    Electronic memory cells are of critical importance in modern-day computing devices, including emerging technology sectors such as large-area printed electronics. One technology that has being receiving significant interest in recent years is resistive switching primarily due to its low dimensionality and nonvolatility. Here, we describe the development of resistive switching memory device arrays based on empty aluminum nanogap electrodes. By employing adhesion lithography, a low-temperature and large-area compatible nanogap fabrication technique, dense arrays of memory devices are demonstrated on both rigid and flexible plastic substrates. As-prepared devices exhibit nonvolatile memory operation with stable endurance, resistance ratios >10⁴ and retention times of several months. An intermittent analysis of the electrode microstructure reveals that controlled resistive switching is due to migration of metal from the electrodes into the nanogap under the application of an external electric field. This alternative form of resistive random access memory is promising for use in emerging sectors such as large-area electronics as well as in electronics for harsh environments, e.g., space, high/low temperature, magnetic influences, radiation, vibration, and pressure.

  11. Semiconductor-Free Nonvolatile Resistive Switching Memory Devices Based on Metal Nanogaps Fabricated on Flexible Substrates via Adhesion Lithography

    KAUST Repository

    Semple, James; Wyatt-Moon, Gwenhivir; Georgiadou, Dimitra G.; McLachlan, Martyn A.; Anthopoulos, Thomas D.

    2017-01-01

    Electronic memory cells are of critical importance in modern-day computing devices, including emerging technology sectors such as large-area printed electronics. One technology that has being receiving significant interest in recent years is resistive switching primarily due to its low dimensionality and nonvolatility. Here, we describe the development of resistive switching memory device arrays based on empty aluminum nanogap electrodes. By employing adhesion lithography, a low-temperature and large-area compatible nanogap fabrication technique, dense arrays of memory devices are demonstrated on both rigid and flexible plastic substrates. As-prepared devices exhibit nonvolatile memory operation with stable endurance, resistance ratios >10⁴ and retention times of several months. An intermittent analysis of the electrode microstructure reveals that controlled resistive switching is due to migration of metal from the electrodes into the nanogap under the application of an external electric field. This alternative form of resistive random access memory is promising for use in emerging sectors such as large-area electronics as well as in electronics for harsh environments, e.g., space, high/low temperature, magnetic influences, radiation, vibration, and pressure.

  12. Synthesis and single crystal growth of perovskite semiconductor CsPbBr3

    Science.gov (United States)

    Zhang, Mingzhi; Zheng, Zhiping; Fu, Qiuyun; Chen, Zheng; He, Jianle; Zhang, Sen; Chen, Cheng; Luo, Wei

    2018-02-01

    As a typical representative of all-inorganic lead halide perovskites, cesium lead bromine (CsPbBr3) has attracted significant attention in recent years. The direct band gap semiconductor CsPbBr3 has a wide band gap of 2.25 eV and high average atomic number (Cs: 55, Pb: 82 and Br: 35), which meet most of the requirements for detection of X- and γ-ray radiation, such as high attenuation, high resistivity, and significant photoconductivity response. However, the growth of large volume CsPbBr3 single crystals remains a challenge. In this paper, the synthesis of CsPbBr3 polycrystalline powders by a chemical co-precipitation method was investigated and the optimum synthesis conditions were obtained. A large CsPbBr3 single crystal of 8 mm diameter and 60 mm length was obtained by a creative electronic dynamic gradient (EDG) method. X-ray diffraction (XRD) patterns and X-ray rocking curve showed that the CsPbBr3 crystal preferentially oriented in the (1 1 0) direction and had a low dislocation density and small residual stress in the crystal. The IR and UV-Vis transmittance and temperature-dependent photoluminescence (PL) spectra showed the crystal had a good basic optical performance. The almost linear current-voltage (I-V) curves implied good ohmic contact between the electrodes and crystal surfaces. The resistivity of the crystal was calculated 109-1010 Ω cm. The above results showed that the quality of the obtained crystal had met the demand of optoelectronic applications.

  13. Fabrication and application of amorphous semiconductor devices

    International Nuclear Information System (INIS)

    Kumurdjian, Pierre.

    1976-01-01

    This invention concerns the design and manufacture of elecric switching or memorisation components with amorphous semiconductors. As is known some compounds, particularly the chalcogenides, have a resistivity of the semiconductor type in the amorphous solid state. These materials are obtained by the high temperature homogeneisation of several single elements such as tellurium, arsenic, germanium and sulphur, followed by water or air quenching. In particular these compounds have useful switching and memorisation properties. In particular they have the characteristic of not suffering deterioration when placed in an environment subjected to nuclear radiations. In order to know more about the nature and properties of these amorphous semiconductors the French patent No. 71 28048 of 30 June 1971 may be consulted with advantage [fr

  14. Optical properties of single semiconductor nanowires and nanowire ensembles. Probing surface physics by photoluminescence spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Pfueller, Carsten

    2011-06-27

    This thesis presents a detailed investigation of the optical properties of semiconductor nanowires (NWs) in general and single GaN NWs and GaN NW ensembles in particular by photoluminescence (PL) spectroscopy. NWs are often considered as potential building blocks for future nanometer-scaled devices. This vision is based on several attractive features that are generally ascribed to NWs. For instance, they are expected to grow virtually free of strain and defects even on substrates with a large structural mismatch. In the first part of the thesis, some of these expectations are examined using semiconductor NWs of different materials. On the basis of the temperature-dependent PL of Au- and selfassisted GaAs/(Al,Ga)As core-shell NWs, the influence of foreign catalyst particles on the optical properties of NWs is investigated. For the Au-assisted NWs, we find a thermally activated, nonradiative recombination channel, possibly related to Auatoms incorporated from the catalyst. These results indicate the limited suitability of catalyst-assisted NWs for optoelectronic applications. The effect of the substrate choice is studied by comparing the PL of ZnO NWs grown on Si, Al{sub 2}O{sub 3}, and ZnO substrates. Their virtually identical optical characteristics indicate that the synthesis of NWs may indeed overcome the constraints that limit the heteroepitaxial deposition of thin films. The major part of this thesis discusses the optical properties of GaN NWs grown on Si substrates. The investigation of the PL of single GaN NWs and GaN NW ensembles reveals the significance of their large surface-to-volume ratio. Differences in the recombination behavior of GaNNW ensembles and GaN layers are observed. First, the large surface-to-volume ratio is discussed to be responsible for the different recombination mechanisms apparent in NWs. Second, certain optical features are only found in the PL of GaN NWs, but not in that of GaN layers. An unexpected broadening of the donor

  15. Single-molecule spectroscopy reveals photosynthetic LH2 complexes switch between emissive states.

    Science.gov (United States)

    Schlau-Cohen, Gabriela S; Wang, Quan; Southall, June; Cogdell, Richard J; Moerner, W E

    2013-07-02

    Photosynthetic organisms flourish under low light intensities by converting photoenergy to chemical energy with near unity quantum efficiency and under high light intensities by safely dissipating excess photoenergy and deleterious photoproducts. The molecular mechanisms balancing these two functions remain incompletely described. One critical barrier to characterizing the mechanisms responsible for these processes is that they occur within proteins whose excited-state properties vary drastically among individual proteins and even within a single protein over time. In ensemble measurements, these excited-state properties appear only as the average value. To overcome this averaging, we investigate the purple bacterial antenna protein light harvesting complex 2 (LH2) from Rhodopseudomonas acidophila at the single-protein level. We use a room-temperature, single-molecule technique, the anti-Brownian electrokinetic trap, to study LH2 in a solution-phase (nonperturbative) environment. By performing simultaneous measurements of fluorescence intensity, lifetime, and spectra of single LH2 complexes, we identify three distinct states and observe transitions occurring among them on a timescale of seconds. Our results reveal that LH2 complexes undergo photoactivated switching to a quenched state, likely by a conformational change, and thermally revert to the ground state. This is a previously unobserved, reversible quenching pathway, and is one mechanism through which photosynthetic organisms can adapt to changes in light intensities.

  16. Single-photon switch: Controllable scattering of photons inside a one-dimensional resonator waveguide

    Science.gov (United States)

    Zhou, L.; Gong, Z. R.; Liu, Y. X.; Sun, C. P.; Nori, F.

    2010-03-01

    We analyze the coherent transport of a single photon, which propagates in a one-dimensional coupled-resonator waveguide and is scattered by a controllable two-level system located inside one of the resonators of this waveguide. Our approach, which uses discrete coordinates, unifies low and high energy effective theories for single-photon scattering. We show that the controllable two-level system can behave as a quantum switch for the coherent transport of a single photon. This study may inspire new electro-optical single-photon quantum devices. We also suggest an experimental setup based on superconducting transmission line resonators and qubits. References: L. Zhou, Z.R. Gong, Y.X. Liu, C.P. Sun, F. Nori, Controllable scattering of photons inside a one-dimensional resonator waveguide, Phys. Rev. Lett. 101, 100501 (2008). L. Zhou, H. Dong, Y.X. Liu, C.P. Sun, F. Nori, Quantum super-cavity with atomic mirrors, Phys. Rev. A 78, 063827 (2008).

  17. Two-dimensional single fluid MHD simulations of plasma opening switches

    International Nuclear Information System (INIS)

    Roderick, N.F.; Payne, S.S.; Peterkin, R.E. Jr.; Frese, M.H.; Hussey, T.W.

    1989-01-01

    Simulations of plasma opening switch have been made using two-dimensional, single fluid, magnetohydrodynamic codes HAM and MACH2. A variety of mechanisms for magnetic field penetration have been investigated. These include plasma convection, classical and microturbulent resistive diffusion, and Hall effect transport. We find that plasma microturbulent models are necessary to explain the broad current channels observed in experiments. Both heuristic and consistent microturbulent models are able to explain observed channel widths and penetration features. The best results are obtained for a consistent model that includes the Buneman, ion acoustic, and lower hybrid microturbulent collision frequencies and threshold conditions. Maximum microturbulent collision frequencies of 5 ω p , are typical. Field transport and current channel profiles are in excellent agreement with experimental observations for GAMBLE I, GAMBLE II, and SUPERMITE experiments. Dominant field penetration mechanisms and center of mass plasma motion are current and density dependent. Including the Hall effect enhanced field penetration. Center of mass motion is negligible for the GAMBLE I experiments but significant for the GAMBLE II conditions. Scaling of plasma opening time with switch length and density can be fit by linear representations for lengths from 0.03 m to 0.24 m and ion densities from 10 18 m -3 to 1.5 times 10 19 m -3 . 15 refs., 7 figs., 1 tab

  18. Quantum dot single-photon switches of resonant tunneling current for discriminating-photon-number detection.

    Science.gov (United States)

    Weng, Qianchun; An, Zhenghua; Zhang, Bo; Chen, Pingping; Chen, Xiaoshuang; Zhu, Ziqiang; Lu, Wei

    2015-03-23

    Low-noise single-photon detectors that can resolve photon numbers are used to monitor the operation of quantum gates in linear-optical quantum computation. Exactly 0, 1 or 2 photons registered in a detector should be distinguished especially in long-distance quantum communication and quantum computation. Here we demonstrate a photon-number-resolving detector based on quantum dot coupled resonant tunneling diodes (QD-cRTD). Individual quantum-dots (QDs) coupled closely with adjacent quantum well (QW) of resonant tunneling diode operate as photon-gated switches- which turn on (off) the RTD tunneling current when they trap photon-generated holes (recombine with injected electrons). Proposed electron-injecting operation fills electrons into coupled QDs which turn "photon-switches" to "OFF" state and make the detector ready for multiple-photons detection. With proper decision regions defined, 1-photon and 2-photon states are resolved in 4.2 K with excellent propabilities of accuracy of 90% and 98% respectively. Further, by identifying step-like photon responses, the photon-number-resolving capability is sustained to 77 K, making the detector a promising candidate for advanced quantum information applications where photon-number-states should be accurately distinguished.

  19. Exciter switch

    Science.gov (United States)

    Mcpeak, W. L.

    1975-01-01

    A new exciter switch assembly has been installed at the three DSN 64-m deep space stations. This assembly provides for switching Block III and Block IV exciters to either the high-power or 20-kW transmitters in either dual-carrier or single-carrier mode. In the dual-carrier mode, it provides for balancing the two drive signals from a single control panel located in the transmitter local control and remote control consoles. In addition to the improved switching capabilities, extensive monitoring of both the exciter switch assembly and Transmitter Subsystem is provided by the exciter switch monitor and display assemblies.

  20. Spectroscopy of Charge Carriers and Traps in Field-Doped Single Crystal Organic Semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Xiaoyang [Columbia Univ., New York, NY (United States); Frisbie, Daniel [Univ. of Minnesota, Minneapolis, MN (United States)

    2017-03-31

    The proposed research aims to achieve quantitative, molecular level understanding of charge carriers and traps in field-doped crystalline organic semiconductors via in situ linear and nonlinear optical spectroscopy, in conjunction with transport measurements and molecular/crystal engineering.

  1. Solution coating of large-area organic semiconductor thin films with aligned single-crystalline domains

    KAUST Repository

    Diao, Ying; Tee, Benjamin C-K.; Giri, Gaurav; Xu, Jie; Kim, Do Hwan; Becerril, Hector A.; Stoltenberg, Randall M.; Lee, Tae Hoon; Xue, Gi; Mannsfeld, Stefan C. B.; Bao, Zhenan

    2013-01-01

    Solution coating of organic semiconductors offers great potential for achieving low-cost manufacturing of large-area and flexible electronics. However, the rapid coating speed needed for industrial-scale production poses challenges to the control

  2. Testing of defects in Si semiconductor apparatus by using single-photon detection

    International Nuclear Information System (INIS)

    Zhongliang, Pan; Ling, Chen; Guangju, Chen

    2013-01-01

    The failure analysis of semiconductor apparatus is very needed for ensuring product quality, which can find several types of defects in the semiconductor apparatus. A new testing method for the defects in Si semiconductor apparatus is presented in this paper, the method makes use of photon emissions to find out the failure positions or failure components by taking advantage of the infrared photo emission characteristics of semiconductor apparatus. These emitted photons carry the information of the apparatus structure. If there are defects in the apparatus, these photons can help in understanding the apparatus properties and detecting the defects. An algorithm for the generation of circuit input vectors are presented in this paper to enhance the strength of the emitted photons for the given components in the semiconductor apparatus. The multiple-valued logic, the static timing analysis and path sensitizations, are used in the algorithm. A lot of experimental results for the Si semiconductor apparatus show that many types of defects such as contact spiking and latchup failure etc., can be detected accurately by the method proposed in this paper

  3. Anomalous optical switching and thermal hysteresis during semiconductor-metal phase transition of VO2 films on Si substrate

    International Nuclear Information System (INIS)

    Leahu, G.; Li Voti, R.; Sibilia, C.; Bertolotti, M.

    2013-01-01

    We present a detailed infrared study of the semiconductor-to-metal transition (SMT) in a vanadium dioxide (VO 2 ) film deposited on silicon wafer. The VO 2 phase transition is studied in the mid-infrared region by analyzing the transmittance and the reflectance measurements, and the calculated emissivity. The reflectance has been measured in two configurations: from the side of the VO 2 film and from that of Si wafer. The results show a strong asymmetry between the emissivity in the two configurations, and the fact that the emissivity dynamic range from the silicon side is twice as large than that from the VO 2 side. The temperature behaviour of the emissivity during the SMT put into evidence the phenomenon of the anomalous absorption in VO 2 , which has been explained by applying the Maxwell Garnett effective medium approximation theory

  4. Real-time observation of conformational switching in single conjugated polymer chains.

    Science.gov (United States)

    Tenopala-Carmona, Francisco; Fronk, Stephanie; Bazan, Guillermo C; Samuel, Ifor D W; Penedo, J Carlos

    2018-02-01

    Conjugated polymers (CPs) are an important class of organic semiconductors that combine novel optoelectronic properties with simple processing from organic solvents. It is important to study CP conformation in solution to understand the physics of these materials and because it affects the properties of solution-processed films. Single-molecule techniques are unique in their ability to extract information on a chain-to-chain basis; however, in the context of CPs, technical challenges have limited their general application to host matrices or semiliquid environments that constrain the conformational dynamics of the polymer. We introduce a conceptually different methodology that enables measurements in organic solvents using the single-end anchoring of polymer chains to avoid diffusion while preserving polymer flexibility. We explore the effect of organic solvents and show that, in addition to chain-to-chain conformational heterogeneity, collapsed and extended polymer segments can coexist within the same chain. The technique enables real-time solvent-exchange measurements, which show that anchored CP chains respond to sudden changes in solvent conditions on a subsecond time scale. Our results give an unprecedented glimpse into the mechanism of solvent-induced reorganization of CPs and can be expected to lead to a new range of techniques to investigate and conformationally manipulate CPs.

  5. Persistence and extinction of a stochastic single-species model under regime switching in a polluted environment II.

    Science.gov (United States)

    Liu, Meng; Wang, Ke

    2010-12-07

    This is a continuation of our paper [Liu, M., Wang, K., 2010. Persistence and extinction of a stochastic single-species model under regime switching in a polluted environment, J. Theor. Biol. 264, 934-944]. Taking both white noise and colored noise into account, a stochastic single-species model under regime switching in a polluted environment is studied. Sufficient conditions for extinction, stochastic nonpersistence in the mean, stochastic weak persistence and stochastic permanence are established. The threshold between stochastic weak persistence and extinction is obtained. The results show that a different type of noise has a different effect on the survival results. Copyright © 2010 Elsevier Ltd. All rights reserved.

  6. Magneto-transport in CdTe/CdMnTe dilute magnetic semiconductor single barrier structures

    International Nuclear Information System (INIS)

    Lyons, V.R.

    1999-03-01

    This thesis presents work done on electrical transport through dilute magnetic semiconductor (DMS) single barriers in both zero and non-zero magnetic fields. The fields are applied either perpendicular or parallel to the DMS layers. The main samples under investigation consist of 100 A and 200 A CdTe/Cd 0.8 Mn 0.2 Te/CdTe single barrier heterostructures. In addition electrical characterisation of the non magnetic layers is performed. Current through the barrier is measured as a function of voltage, magnetic field and temperature. A theoretical model is derived in order to calculate the current as a function of barrier height, barrier width, emitting layer carrier concentration, applied bias and temperature. These variables are then treated as fitting parameters and comparisons are made between the calculated and the experimental currents. The barriers are shown to produce non-Ohmic transport. The roles of quantum mechanical tunnelling and thermal activation across the barrier are investigated and shown to be highly mixed. An unexpectedly high degree of tunnelling is found to occur at high temperatures, within the region previously assumed to be dominated by thermal activation. Moreover the barrier height is found to be lower and the width greater than expected. These observations suggest that a high level of Mn diffusion occurs, possibly due to In dopant related effects. This suggestion is validated by the high emitting layer carrier concentration suggested by the fitting. At low temperatures and voltages the thicker barrier sample is shown to contain a parasitic leak path which short-circuits the barrier. This leak may exist in both samples but only becomes dominant where the barriers are sufficiently opaque to the incident carriers. Changes in a magnetic field are expected to be due to sp-d exchange induced giant Zeeman splitting in the barrier and either normal spin splitting or sp-d exchange effects in the emitter regions. The application of a magnetic field is

  7. A novel single-phase flux-switching permanent magnet linear generator used for free-piston Stirling engine

    Science.gov (United States)

    Zheng, Ping; Sui, Yi; Tong, Chengde; Bai, Jingang; Yu, Bin; Lin, Fei

    2014-05-01

    This paper investigates a novel single-phase flux-switching permanent-magnet (PM) linear machine used for free-piston Stirling engines. The machine topology and operating principle are studied. A flux-switching PM linear machine is designed based on the quasi-sinusoidal speed characteristic of the resonant piston. Considering the performance of back electromotive force and thrust capability, some leading structural parameters, including the air gap length, the PM thickness, the ratio of the outer radius of mover to that of stator, the mover tooth width, the stator tooth width, etc., are optimized by finite element analysis. Compared with conventional three-phase moving-magnet linear machine, the proposed single-phase flux-switching topology shows advantages in less PM use, lighter mover, and higher volume power density.

  8. Numerical analysis of intrinsic bistability and chromatic switching in Tm3+ single-doped systems under photon avalanche pumping scheme

    International Nuclear Information System (INIS)

    Li Li; Zhang Xinlu; Chen Lixue

    2008-01-01

    In this paper, we predict and numerically demonstrate the intrinsic intensity bistability, spectra bistability and chromatic switching of visible-infrared emission in Tm 3+ single-doped systems that are pumped by the photon avalanche scheme at 648 nm. Based on the coupled rate equation theory, the evolutions of the populations at various Tm 3+ energy levels, emission spectra and fluorescence intensity versus pump excitation are numerically investigated in detail. The results show that intrinsic optical bistability (IOB) associated with emission spectra and luminescence intensity takes place in the vicinity of the avalanche threshold (∼10 kW cm -2 ). When the pump excitation rises above the switching threshold (∼17.5 kW cm -2 ), the chromatic switching between the infrared (1716 nm) and the visible blue (452/469 nm) spectra can be performed. Moreover, the influences of system parameters on IOB and the origin of chromatic switching are discussed. These unique characteristics of Tm 3+ -doped systems would lead to the new possibility of the development of pump-controlled all-solid-state luminescence switches and optical bistability switches.

  9. Bianthrone in a Single-Molecule Junction: Conductance Switching with a Bistable Molecule Facilitated by Image Charge Effects

    DEFF Research Database (Denmark)

    Bjørnholm, Thomas

    2010-01-01

    Bianthrone is a sterically hindered compound that exists in the form of two nonplanar isomers. Our experimental study of single-molecule junctions with bianthrone reveals persistent switching of electric conductance at low temperatures, which can be reasonably associated with molecular isomerizat...

  10. An injection seeded single frequency Nd:YAG Q-switched laser with precisely controllable laser pulse firing time

    Science.gov (United States)

    Wu, Frank F.; Khizhnyak, Anatoliy; Markov, Vladimir

    2010-02-01

    We have realized a single frequency Q-switched Nd:YAG laser with precisely controllable lasing time and thus enabled synchronization of multi-laser systems. The use of injection seeding to the slave ring oscillator results in unidirectional Q-switched laser oscillation with suppression of bidirectional Q-switched oscillation that otherwise would be initiated from spontaneous emission if the seeding laser is not present. Under normal condition, the cavity is high in loss during the pumping period; then a Pockels cell opens the cavity to form the pulse build up, with a second Pockels cell to perform cavity dumping, generating the Q-switched pulse output with optimized characteristics. The two Pockels cells can be replaced by a single unit if an adjustable gated electrical pulse is applied to the Pockels cell in which the pulse front is used to open the cavity and the falling edge to dump the laser pulse. Proper selection of the pump parameters and Pockels-cell gating enables operation of the system in a mode in which the Q-switched pulse can be formed only under the seeding condition. The advantage of the realized regime is in stable laser operation with no need in adjustment of the seeded light wavelength and the mode of the cavity. It is found that the frequency of the Q-switched laser radiation matches well to the injected seeded laser mode. By using two-stage amplifiers, an output energy better than 300 mJ has been achieved in MOPA configuration without active control of the cavity length and with pulse width adjustability from several nanoseconds to 20 ns. The Q-switched oscillator operates not only at precisely controlled firing time but also can be tuned over wide range. This will enable multi-laser systems synchronization and frequency locking down each other if necessary.

  11. Computer-automated tuning of semiconductor double quantum dots into the single-electron regime

    NARCIS (Netherlands)

    Baart, T.A.; Eendebak, P.T.; Reichl, C.; Wegscheider, W.; Vandersypen, L.M.K.

    2016-01-01

    We report the computer-automated tuning of gate-defined semiconductor double quantum dots in GaAs heterostructures. We benchmark the algorithm by creating three double quantum dots inside a linear array of four quantum dots. The algorithm sets the correct gate voltages for all the gates to tune the

  12. Manipulation of spin states in single II-VI-semiconductor quantum dots; Manipulation von Spinzustaenden in einzelnen II-VI-Halbleiter-Quantenpunkten

    Energy Technology Data Exchange (ETDEWEB)

    Hundt, Andreas

    2007-10-09

    Semiconductor quantum dots (QD) are objects on the nanometer scale, where charge carriers are confined in all three dimensions. This leads to a reduced interaction with the semiconductor lattice and to a discrete density of states. The spin state of a particle defines the polarisation of the emitted light when relaxating to an energetically lower state. Spin exchange and optical transition selection rules (conservation law for spin) define the optical control of spin states. In the examined QD in II-VI seminconductor systems the large polar character of the bindings enables to observe particle interactions by spectroscopy of the photo-luminescence (PL), making QD attractive for basic research. This work subjects in its first part single negatively charged non-magnetic QD. The odd number of carriers allows to study the latter in an unpaired state. By using polarization-resolved micro-PL spectroscopy, the spin-states of single, isolated QD can be studied reproducibly. Of special interest are exchange interactions in this few-particle system named trion. By excitation spectroscopy energetically higher states can be identified and characterized. The exchange interactions appearing here lead to state mixing and fine structure patterns in the spectra. Couplings in excited hole states show the way to the optical orientation of the resident electron spin. The spin configuration of the trion triplet state can be used to optically control the resident electron spin. Semimagnetic QD are focused in the second part of this work. The interaction with a paramagnetic environment of manganese spins leads to new magneto-optical properties of the QD. They reveal on a single dot level by line broadening due to spin fluctuations and by the giant Zeeman effect of the dot ensemble. Of special interest in this context is the influence of the reduced system dimension and the relatively larger surface of the system on the exchange mechanisms. The strong temperature dependence of the spin

  13. Mismatched single stranded antisense oligonucleotides can induce efficient dystrophin splice switching

    Directory of Open Access Journals (Sweden)

    Kole Ryszard

    2011-10-01

    Full Text Available Abstract Background Antisense oligomer induced exon skipping aims to reduce the severity of Duchenne muscular dystrophy by redirecting splicing during pre-RNA processing such that the causative mutation is by-passed and a shorter but partially functional Becker muscular dystrophy-like dystrophin isoform is produced. Normal exons are generally targeted to restore the dystrophin reading frame however, an appreciable subset of dystrophin mutations are intra-exonic and therefore have the potential to compromise oligomer efficiency, necessitating personalised oligomer design for some patients. Although antisense oligomers are easily personalised, it remains unclear whether all patient polymorphisms within antisense oligomer target sequences will require the costly process of producing and validating patient specific compounds. Methods Here we report preclinical testing of a panel of splice switching antisense oligomers, designed to excise exon 25 from the dystrophin transcript, in normal and dystrophic patient cells. These patient cells harbour a single base insertion in exon 25 that lies within the target sequence of an oligomer shown to be effective at removing exon 25. Results It was anticipated that such a mutation would compromise oligomer binding and efficiency. However, we show that, despite the mismatch an oligomer, designed and optimised to excise exon 25 from the normal dystrophin mRNA, removes the mutated exon 25 more efficiently than the mutation-specific oligomer. Conclusion This raises the possibility that mismatched AOs could still be therapeutically applicable in some cases, negating the necessity to produce patient-specific compounds.

  14. Synchronous optical packet switch architecture with tunable single and multi-channels wavelength converters

    Science.gov (United States)

    Hamza, Haitham S.; Adel, Reham

    2017-07-01

    In this paper, we propose a bufferless synchronous optical packet switch (OPS) architecture named the Limited-range wavelength conversion with Dynamic Pump-wavelength Selection (LDPS) architecture. LDPS is equipped with a dedicated limited-range wavelength converters (LRWCs, and a shared pool of parametric wavelength converters (PWCs) with dynamic pump-wavelength selection (DPS). The adoption of hybrid conversion types in the proposed architecture aims at improving the packet loss rate (PLR) compared to conventional architecture with single conversion types, while reducing (or at least maintaining) the conversion distance (d) of used wavelength converters. Packet contention in the proposed architecture is resolved using the first available algorithm (FAA) and the dynamic pump-wavelength selection algorithm (DPSA). The performance of the proposed architecture is compared to two well-known conventional architectures; namely, the LRWC architecture that uses dedicated LRWCS for each input wavelength, and the DPS architecture that uses a shared pool of dynamic pump-wavelength converters (PWCs). Simulation results show that, for the same value of d, the new architecture reduces the PLR compared to the LRWC architecture by up to 40 % and 99.7 % for traffic loads, 0.5 and 1; respectively. In addition, for d = 1 , the new architecture reduces the PLR compared to the DPS architecture by up to 10 % and 99.3 % for traffic loads, 0.5 and 1; respectively.

  15. Elaboration and characterization of a KCl single crystal doped with nanocrystals of a Sb2O3 semiconductor

    International Nuclear Information System (INIS)

    Bouhdjer, L.; Addala, S.; Halimi, O.; Boudine, B.; Sebais, M.; Chala, A.

    2013-01-01

    Undoped and doped KCl single crystals have been successfully elaborated via the Czochralski (Cz) method. The effects of dopant Sb 2 O 3 nanocrystals on structural and optical properties were investigated by a number of techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDAX) analysis, UV-visible and photoluminescence (PL) spectrophotometers. An XRD pattern of KCl:Sb 2 O 3 reveals that the Sb 2 O 3 nanocrystals are in the well-crystalline orthorhombic phase. The broadening of diffraction peaks indicated the presence of a Sb 2 O 3 semiconductor in the nanometer size regime. The shift of absorption and PL peaks is observed near 334 nm and 360 nm respectively due to the quantum confinement effect in Sb 2 O 3 nanocrystals. Particle sizes calculated from XRD studies agree fairly well with those estimated from optical studies. An SEM image of the surface KCl:Sb 2 O 3 single crystal shows large quasi-spherical of Sb 2 O 3 crystallites scattered on the surface. The elemental analysis from EDAX demonstrates that the KCl:Sb 2 O 3 single crystal is slightly rich in oxygen and a source of excessive quantities of oxygen is discussed. (semiconductor materials)

  16. Implementation of Single Phase Soft Switched PFC Converter for Plug-in-Hybrid Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Aiswariya Sekar

    2015-11-01

    Full Text Available This paper presents a new soft switching boost converter with a passive snubber cell without additional active switches for battery charging systems. The proposed snubber finds its application in the front-end ac-dc converter of Plug-in Hybrid Electric Vehicle (PHEV battery chargers. The proposed auxiliary snubber circuit consists of an inductor, two capacitors and two diodes. The new converter has the advantages of continuous input current, low switching stresses, high voltage gain without extreme duty cycle, minimized charger size and charging time and fewer amounts of cost and electricity drawn from the utility at higher switching frequencies. The switch is made to turn ON by Zero Current Switching (ZCS and turn OFF by Zero Voltage Switching (ZVS. The detailed steady state analysis of the novel ac-dc Zero Current- Zero Voltage Switching (ZC-ZVS boost Power Factor Correction (PFC converter is presented with its operating principle. The experimental prototype of 20 kHz, 100 W converter verifies the theoretical analysis. The power factor of the prototype circuit reaches near unity with an efficiency of 97%, at nominal output power for a ±10% variation in the input voltage and ±20% variation in the snubber component values.

  17. Nuclear data relevant to single event upsets in semiconductor memories induced by cosmic-ray neutrons and protons

    International Nuclear Information System (INIS)

    Watanabe, Yukinobu

    2008-01-01

    The role of nuclear data is examined in the study of single event upset (SEU) phenomena in semiconductor memories caused by cosmic-ray neutrons and protons. Neutron and proton SEU cross sections are calculated with a simplified semi-empirical model using experimental heavy-ion SEU cross-sections and a dedicated database of neutron and proton induced reactions on 28 Si. Some impacts of the nuclear reaction data on SEU simulation are analyzed by investigating relative contribution of secondary ions and neutron elastic scattering to SEU and influence of simultaneous multiple ions emission on SEU. (author)

  18. Thin film complementary metal oxide semiconductor (CMOS) device using a single-step deposition of the channel layer

    KAUST Repository

    Nayak, Pradipta K.

    2014-04-14

    We report, for the first time, the use of a single step deposition of semiconductor channel layer to simultaneously achieve both n-and p-type transport in transparent oxide thin film transistors (TFTs). This effect is achieved by controlling the concentration of hydroxyl groups (OH-groups) in the underlying gate dielectrics. The semiconducting tin oxide layer was deposited at room temperature, and the maximum device fabrication temperature was 350C. Both n and p-type TFTs showed fairly comparable performance. A functional CMOS inverter was fabricated using this novel scheme, indicating the potential use of our approach for various practical applications.

  19. Single-electron-occupation metal-oxide-semiconductor quantum dots formed from efficient poly-silicon gate layout

    Energy Technology Data Exchange (ETDEWEB)

    Carroll, Malcolm S.; rochette, sophie; Rudolph, Martin; Roy, A. -M.; Curry, Matthew Jon; Ten Eyck, Gregory A.; Manginell, Ronald P.; Wendt, Joel R.; Pluym, Tammy; Carr, Stephen M; Ward, Daniel Robert; Lilly, Michael; pioro-ladriere, michel

    2017-07-01

    We introduce a silicon metal-oxide-semiconductor quantum dot structure that achieves dot-reservoir tunnel coupling control without a dedicated barrier gate. The elementary structure consists of two accumulation gates separated spatially by a gap, one gate accumulating a reservoir and the other a quantum dot. Control of the tunnel rate between the dot and the reservoir across the gap is demonstrated in the single electron regime by varying the reservoir accumulation gate voltage while compensating with the dot accumulation gate voltage. The method is then applied to a quantum dot connected in series to source and drain reservoirs, enabling transport down to the single electron regime. Finally, tuning of the valley splitting with the dot accumulation gate voltage is observed. This split accumulation gate structure creates silicon quantum dots of similar characteristics to other realizations but with less electrodes, in a single gate stack subtractive fabrication process that is fully compatible with silicon foundry manufacturing.

  20. Advantages of using a two-switch forward in single-stage power factor corrected power supplies

    DEFF Research Database (Denmark)

    Petersen, Lars

    2000-01-01

    A single-stage power factor corrected power supply using a two-switch forward is proposed to increase efficiency. The converter is operated in the DCM (discontinues conduction mode) and it is shown that this operation mode ensures the intermediate DC-bus to be controlled only by means of circuit...... supply has been implemented. The measured efficiency is between 85% and 88.5% in the range 30 W-500 W and the measured power factor at full load is 0.95....... parameters and therefore independent of load variations. The DCM operation often has a diminishing effect on the efficiency but by use of the two-switch topology high efficiency with minimum circuit complexity can be achieved in this mode. A 500 W 70 V prototype of the two-switch boost-forward PFC power...

  1. Organic Single-Crystal Semiconductor Films on a Millimeter Domain Scale.

    Science.gov (United States)

    Kwon, Sooncheol; Kim, Jehan; Kim, Geunjin; Yu, Kilho; Jo, Yong-Ryun; Kim, Bong-Joong; Kim, Junghwan; Kang, Hongkyu; Park, Byoungwook; Lee, Kwanghee

    2015-11-18

    Nucleation and growth processes can be effectively controlled in organic semiconductor films through a new concept of template-mediated molecular crystal seeds during the phase transition; the effective control of these processes ensures millimeter-scale crystal domains, as well as the performance of the resulting organic films with intrinsic hole mobility of 18 cm(2) V(-1) s(-1). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Single Anastomosis Duodeno-Ileal Switch (SADIS): A Systematic Review of Efficacy and Safety.

    Science.gov (United States)

    Shoar, Saeed; Poliakin, Lauren; Rubenstein, Rebecca; Saber, Alan A

    2018-01-01

    Owing to the possibility of weight regain after the long-term follow-up of gastric bypass patients and because of the high morbidity of biliopancreatic diversion with duodenal switch, single-anastomosis duodeno-ileal switch (SADIS) has emerged as a rescue procedure in bariatric surgery. The purpose of this review is to summarize the literature data on SADIS. University Hospital, NY. A comprehensive literature review was performed through October 2016 to identify English studies on SADIS performed in human subjects. Outcomes of interest were technical considerations, postoperative complications, weight loss outcome, comorbidity resolution rate, and nutritional deficiency after SADIS. A total of 12 studies including 581 SADIS patients (217 males and 364 females) were included. SADIS was a primary procedure in 508 patients (87.4%) and a conversion procedure in 73 patients (12.6%). The length of common limb was 300 cm in 54.2%, 250 cm in 23%, and 200 cm in 13.4% of patients. Anastomosis technique was a linear stapler in 26.7% and a hand sewn suture technique in 73.3% of patients. Diarrhea was the most common complication (1.2%). The average %EWL was 30% at 3 months, 55% at 6 months, 70% at 1 year, and 85% at 2 years. Co-morbidity resolution rate was 74.1% for type 2 diabetes mellitus, 96.3% for hypertension, 68.3% for dyslipidemia, 63.3% for obstructive sleep apnea, and 87.5% for GERD. Overall, vitamin A, selenium, and iron deficiency were the most common nutritional deficiencies with the possibility of the protein malnutrition in up to 34% of the patients when measured. As a modified bariatric procedure, SADIS has promising outcomes for weight loss and comorbidity resolution in morbidly obese patients. When measured, there was a high prevalence of macro-nutrient deficiencies following SADIS. There is a high technical variability, and long-term data are required before any meaningful conclusion can be made.

  3. EDITORIAL: Molecular switches at surfaces Molecular switches at surfaces

    Science.gov (United States)

    Weinelt, Martin; von Oppen, Felix

    2012-10-01

    electron-vibration coupling in transport through single moleculesKatharina J Franke and Jose Ignacio Pascual Vibrational heating in single-molecule switches: an energy-dependent density-of-states approachT Brumme, R Gutierrez and G Cuniberti Reversible switching of single tin phthalocyanine molecules on the InAs(111)A surfaceC Nacci, K Kanisawa and S Fölsch Tuning the interaction between carbon nanotubes and dipole switches: the influence of the change of the nanotube-spiropyran distanceP Bluemmel, A Setaro, C Maity, S Hecht and S Reich Carbon nanotubes as substrates for molecular spiropyran-based switchesE Malic, A Setaro, P Bluemmel, Carlos F Sanz-Navarro, Pablo Ordejón, S Reich and A Knorr Ultrafast dynamics of dithienylethenes differently linked to the surface of TiO2 nanoparticlesLars Dworak, Marc Zastrow, Gehad Zeyat, Karola Rück-Braun and Josef Wachtveitl Switching the electronic properties of Co-octaethylporphyrin molecules on oxygen-covered Ni films by NO adsorptionC F Hermanns, M Bernien, A Krüger, J Miguel and W Kuch STM-switching of organic molecules on semiconductor surfaces: an above threshold density matrix model for 1,5 cyclooctadiene on Si(100)K Zenichowski, Ch Nacci, S Fölsch, J Dokić, T Klamroth and P Saalfrank A switch based on self-assembled thymineFatih Kalkan, Michael Mehlhorn and Karina Morgenstern The growth and electronic structure of azobenzene-based functional molecules on layered crystalsJ Iwicki, E Ludwig, J Buck, M Kalläne, F Köhler, R Herges, L Kipp and K Rossnagel Voltage-dependent conductance states of a single-molecule junctionY F Wang, N Néel, J Kröger, H Vázquez, M Brandbyge, B Wang and R Berndt Molecules with multiple switching units on a Au(111) surface: self-organization and single-molecule manipulationJohannes Mielke, Sofia Selvanathan, Maike Peters, Jutta Schwarz, Stefan Hecht and Leonhard Grill Preparing and regulating a bi-stable molecular switch by atomic manipulationS Sakulsermsuk, R E Palmer and P A Sloan Mixed self

  4. Double switching hysteresis loop in a single layer Fe3Pt alloy thin films

    International Nuclear Information System (INIS)

    Nahid, M.A.I.; Suzuki, Takao

    2008-01-01

    The Fe 3 Pt alloy thin films were epitaxially grown on MgO(100) substrate by e-beam evaporation. The films were partially ordered at the substrate deposition temperature above 350 deg. C. These partially ordered films exhibit very large biaxial magnetic anisotropy constant in the order of 10 5 J/m 3 and produce double switching in the hysteresis loops. The difference of the switching field of these films can be up to about 3 x 10 5 A/m by tuning the angle of the applied field with respect to the easy axes. This double switching behavior stems from the large biaxial magnetic anisotropy of the films

  5. New switching processes using the integrated protections of power semi-conductors: application to the development of static converters with self-switching process; nouveaux mecanismes de commutation exploitant les protections integrees des semi-conducteurs de puissance: application a la conception de convertisseurs statiques a commutation automatique

    Energy Technology Data Exchange (ETDEWEB)

    Roux, N.

    2004-07-15

    This thesis deals with a new switching process which integrates the semiconductor protection directly in the switching principle, in order to generate new static converters. It consists of a self-controlled transition which proceeds on a non-zero current or voltage level. 2 It can be associated with controlled or naturally switching processes making it possible to go from two to five change of state types of a switching cell. So, new elementary operation rules of a switching cell emerge. Considering the great number of possible switches, a synthesis methodology of cells with a source reversibility, whose switches are identical, is presented making it possible to reveal various solutions, of which two seem particularly interesting: the self-breaking inverter and rectifier cells, both using the self-breaking thyristor-dual. This last is used as study support of the self-breaking principle. Then, the manuscript concentrates on the study of converters, associations of elementary cells, revealing in particular the DC-current transformer and the reversible three-phase self-breaking rectifier. This last had been developed as an industrial prototype. Lastly, starting from the concept of a wind chain, our assembly has been compared with what is presently done as network converters, revealing lesser losses as well as a higher energetic efficiency. (author)

  6. Intrinsic spin and momentum relaxation in organic single-crystalline semiconductors probed by ESR and Hall measurements

    Science.gov (United States)

    Tsurumi, Junto; Häusermann, Roger; Watanabe, Shun; Mitsui, Chikahiko; Okamoto, Toshihiro; Matsui, Hiroyuki; Takeya, Jun

    Spin and charge momentum relaxation mechanism has been argued among organic semiconductors with various methods, devices, and materials. However, little is known in organic single-crystalline semiconductors because it has been hard to obtain an ideal organic crystal with an excellent crystallinity and controllability required for accurate measurements. By using more than 1-inch sized single crystals which are fabricated via contentious edge-casting method developed by our group, we have successfully demonstrated a simultaneous determination of spin and momentum relaxation time for gate-induced charges of 3,11-didecyldinaphtho[2,3- d:2',3'- d']benzo[1,2- b:4,5- b']dithiophene, by combining electron spin resonance (ESR) and Hall effect measurements. The obtained temperature dependences of spin and momentum relaxation times are in good agreement in terms of power law with a factor of approximately -2. It is concluded that Elliott-Yafet spin relaxation mechanism can be dominant at room temperature regime (200 - 300 K). Probing characteristic time scales such as spin-lattice, spin-spin, and momentum relaxation times, demonstrated in the present work, would be a powerful tool to elucidate fundamental spin and charge transport mechanisms. We acknowledge the New Energy and Industrial Technology Developing Organization (NEDO) for financial support.

  7. Q-Switched High Power Single Frequency 2 Micron Fiber Laser, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Accurate measurement of atmospheric parameters with high resolution needs advanced lasers. In this SBIR program we propose to develop innovative Q-switched high...

  8. Single-site approximation for the s-f model of antiferromagnetic semiconductors

    International Nuclear Information System (INIS)

    Takahashi, Masao; Nolting, Wolfgang

    2001-01-01

    For the s-f model of an antiferromagnetic semiconductor, the effect of the antiferromagnetic ordering of the localized spins on the conduction-electron state is investigated over a wide range of exchange strengths by combining the effective-medium approach with the Green's function in the 2x2 sublattice Bloch function representation. The band splitting due to the reduced magnetic Brillouin zone occurs below the Neel temperature. There is a marked effect of the thermal fluctuation of the antiferromagnetically ordered localized spins on the conduction electron at the energies near the top (bottom) of the lower- (higher-) energy subband

  9. Realization of a four-step molecular switch in scanning tunneling microscope manipulation of single chlorophyll-a molecules

    Science.gov (United States)

    Iancu, Violeta; Hla, Saw-Wai

    2006-01-01

    Single chlorophyll-a molecules, a vital resource for the sustenance of life on Earth, have been investigated by using scanning tunneling microscope manipulation and spectroscopy on a gold substrate at 4.6 K. Chlorophyll-a binds on Au(111) via its porphyrin unit while the phytyl-chain is elevated from the surface by the support of four CH3 groups. By injecting tunneling electrons from the scanning tunneling microscope tip, we are able to bend the phytyl-chain, which enables the switching of four molecular conformations in a controlled manner. Statistical analyses and structural calculations reveal that all reversible switching mechanisms are initiated by a single tunneling-electron energy-transfer process, which induces bond rotation within the phytyl-chain. PMID:16954201

  10. Tuning and Switching Enantioselectivity of Asymmetric Carboligation in an Enzyme through Mutational Analysis of a Single Hot Spot.

    Science.gov (United States)

    Wechsler, Cindy; Meyer, Danilo; Loschonsky, Sabrina; Funk, Lisa-Marie; Neumann, Piotr; Ficner, Ralf; Brodhun, Florian; Müller, Michael; Tittmann, Kai

    2015-12-01

    Enantioselective bond making and breaking is a hallmark of enzyme action, yet switching the enantioselectivity of the reaction is a difficult undertaking, and typically requires extensive screening of mutant libraries and multiple mutations. Here, we demonstrate that mutational diversification of a single catalytic hot spot in the enzyme pyruvate decarboxylase gives access to both enantiomers of acyloins acetoin and phenylacetylcarbinol, important pharmaceutical precursors, in the case of acetoin even starting from the unselective wild-type protein. Protein crystallography was used to rationalize these findings and to propose a mechanistic model of how enantioselectivity is controlled. In a broader context, our studies highlight the efficiency of mechanism-inspired and structure-guided rational protein design for enhancing and switching enantioselectivity of enzymatic reactions, by systematically exploring the biocatalytic potential of a single hot spot. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Effect of temperature and phonons on the spectral properties of a multi-level semiconductor quantum dot single-photon source

    DEFF Research Database (Denmark)

    Nielsen, Per Kær; Nielsen, Torben Roland; Lodahl, Peter

    2009-01-01

    Since it was realized that efficient quantum computing can be performed using single photons and standard linear optics elements, immense international research activity has been aimed at developing semiconductor quantum dot (QD) single-photon sources (SPS). In order to optimise the design of SPS...... us to study complicated multi-level QDs, not possible within the commonly used independent boson model (IBM)....

  12. Dipolar molecules inside C-70: an electric field-driven room-temperature single-molecule switch

    Czech Academy of Sciences Publication Activity Database

    Foroutan-Nejad, C.; Andrushchenko, Valery; Straka, Michal

    2016-01-01

    Roč. 18, č. 48 (2016), s. 32673-32677 ISSN 1463-9076 R&D Projects: GA ČR(CZ) GA14-03564S Institutional support: RVO:61388963 Keywords : room-temperature single-molecule switch * electric field * endohedral fullerene * density functional calculations Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.123, year: 2016 http://pubs.rsc.org/en/content/articlepdf/2016/cp/c6cp06986j

  13. Hybrid switch for resonant power converters

    Science.gov (United States)

    Lai, Jih-Sheng; Yu, Wensong

    2014-09-09

    A hybrid switch comprising two semiconductor switches connected in parallel but having different voltage drop characteristics as a function of current facilitates attainment of zero voltage switching and reduces conduction losses to complement reduction of switching losses achieved through zero voltage switching in power converters such as high-current inverters.

  14. A compact seven switches topology and reduced DC-link capacitor size for single-phase stand-alone PV system with hybrid energy storages

    DEFF Research Database (Denmark)

    Liu, Xiong; Wang, Peng; Loh, Poh Chiang

    2011-01-01

    Single-phase stand-alone PV system is suitable for household applications in remote area. Hybrid battery/ultra-capacitor energy storage can reduce charge and discharge cycles and avoid deep discharges of battery. This paper proposes a compact seven switches structure for stand-alone PV system......, which otherwise needs nine switches configuration, inclusive of one switch for boost converter, four switches for single-phase inverter and four switches for two DC/DC converters of battery and ultra-capacitor. It is well-known that a bulky DC-link capacitor is always required to absorb second......-order harmonic current caused by single-phase inverter. In the proposed compact topology, a small size DC-link capacitor can achieve the same function through charging/discharging control of ultra-capacitor to mitigate second-order ripple current. Simulation results are provided to validate the effectiveness...

  15. A single-gap transflective fringe field switching display using a liquid crystal with positive dielectric anisotropy

    International Nuclear Information System (INIS)

    Lim, Young Jin; Lee, Myong-Hoon; Lee, Gi-Dong; Jang, Won-Gun; Lee, Seung Hee

    2007-01-01

    There is considerable difficulty in fabricating a reflector with embossing in an array substrate using a conventional single gap transflective fringe-field switching nematic liquid-crystal display. In order to solve this problem, we propose a new structure, which consists of a reflector on a colour filter substrate. The newly proposed structure with a complex field direction has problems such that the voltage-dependent transmittance and reflectance curves do not match each other, which necessitate a dual driving circuit. This paper reports the optimized electrode structure and calculated electro-optical results realizing a single gamma curve and high light efficiency

  16. Heat and mass transfer in semiconductor melts during single-crystal growth processes

    Science.gov (United States)

    Kakimoto, Koichi

    1995-03-01

    The quality of large semiconductor crystals grown from melts is significantly affected by the heat and mass transfer in the melts. The current understanding of the phenomena, especially melt convection, is reviewed starting from the results of visualization using model fluids or silicon melt, and continuing to the detailed numerical calculations needed for quantitative modeling of processing with solidification. The characteristics of silicon flows are also reviewed by focusing on the Coriolis force in the rotating melt. Descriptions of flow instabilities are included that show the level of understanding of melt convection with a low Prandtl number. Based on hydrodynamics, the origin of the silicon flow structure is reviewed, and it is discussed whether silicon flow is completely turbulent or has an ordered structure. The phase transition from axisymmetric to nonaxisymmetric flow is discussed using different geometries. Additionally, surface-tension-driven flow is reviewed for Czochralski crystal growth systems.

  17. Coulomb blockade anisotropic magnetoresistance and voltage controlled magnetic switching in a ferromagnetic GaMnAs single electron transistor

    Czech Academy of Sciences Publication Activity Database

    Wunderlich, J.; Jungwirth, Tomáš; Irvine, A.C.; Kaestner, B.; Shick, Alexander; Campion, R. P.; Williams, D.A.; Gallagher, B. L.

    2007-01-01

    Roč. 310, - (2007), s. 1883-1888 ISSN 0304-8853 R&D Projects: GA ČR GA202/05/0575; GA MŠk LC510; GA ČR GEFON/06/E002 EU Projects: European Commission(XE) 015728 - NANOSPIN Institutional research plan: CEZ:AV0Z10100521; CEZ:AV0Z10100520 Keywords : ferromagnetic semiconductors * magnetoresistance * single-electron transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.704, year: 2007

  18. "Switching on" the properties of single-molecule magnetism in triangular manganese(III) complexes.

    Science.gov (United States)

    Stamatatos, Theocharis C; Foguet-Albiol, Dolos; Lee, Sheng-Chiang; Stoumpos, Constantinos C; Raptopoulou, Catherine P; Terzis, Aris; Wernsdorfer, Wolfgang; Hill, Stephen O; Perlepes, Spyros P; Christou, George

    2007-08-01

    -frequency EPR spectra of single crystals of 4.3CH2Cl2 have provided precise spin Hamiltonian parameters, giving D = -0.3 cm(-1), B40 = -3 x 10(-5) cm(-1), and g = 2.00. The spectra also suggest a significant transverse anisotropy of E > or = 0.015 cm(-1). The combined work demonstrates the feasibility that structural distortions of a magnetic core imposed by peripheral ligands can "switch on" the properties of an SMM.

  19. Development of a high throughput single-particle screening for inorganic semiconductor nanorods as neural voltage sensor

    Science.gov (United States)

    Kuo, Yung; Park, Kyoungwon; Li, Jack; Ingargiola, Antonino; Park, Joonhyuck; Shvadchak, Volodymyr; Weiss, Shimon

    2017-08-01

    Monitoring membrane potential in neurons requires sensors with minimal invasiveness, high spatial and temporal (sub-ms) resolution, and large sensitivity for enabling detection of sub-threshold activities. While organic dyes and fluorescent proteins have been developed to possess voltage-sensing properties, photobleaching, cytotoxicity, low sensitivity, and low spatial resolution have obstructed further studies. Semiconductor nanoparticles (NPs), as prospective voltage sensors, have shown excellent sensitivity based on Quantum confined Stark effect (QCSE) at room temperature and at single particle level. Both theory and experiment have shown their voltage sensitivity can be increased significantly via material, bandgap, and structural engineering. Based on theoretical calculations, we synthesized one of the optimal candidates for voltage sensors: 12 nm type-II ZnSe/CdS nanorods (NRs), with an asymmetrically located seed. The voltage sensitivity and spectral shift were characterized in vitro using spectrally-resolved microscopy using electrodes grown by thin film deposition, which "sandwich" the NRs. We characterized multiple batches of such NRs and iteratively modified the synthesis to achieve higher voltage sensitivity (ΔF/F> 10%), larger spectral shift (>5 nm), better homogeneity, and better colloidal stability. Using a high throughput screening method, we were able to compare the voltage sensitivity of our NRs with commercial spherical quantum dots (QDs) with single particle statistics. Our method of high throughput screening with spectrally-resolved microscope also provides a versatile tool for studying single particles spectroscopy under field modulation.

  20. Single molecular switch based on thiol tethered iron(II)clathrochelate on gold

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, Subramanian [Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima 10, 10-747 Olsztyn (Poland); Voloshin, Yan Z. [Nesmeyanov Institute of Organoelement Compounds of the Russian Academy of Sciences, 119991 Moscow (Russian Federation); Radecka, Hanna [Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima 10, 10-747 Olsztyn (Poland); Radecki, Jerzy [Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Tuwima 10, 10-747 Olsztyn (Poland)], E-mail: radecki@pan.olsztyn.pl

    2009-09-30

    Molecular electronics has been associated with high density nano-electronic devices. Developments of molecular electronic devices were based on reversible switching of molecules between the two conductive states. In this paper, self-assembled monolayers of dodecanethiol (DDT) and thiol tethered iron(II)clathrochelate (IC) have been prepared on gold film. The electrochemical and electronic properties of IC molecules inserted into the dodecanethiol monolayer (IC-DDT SAM) were investigated using voltammetric, electrochemical impedance spectroscopy (EIS), scanning tunneling microscopy (STM) and cross-wire tunneling measurements. The voltage triggered switching behaviour of IC molecules on mixed SAM was demonstrated. Deposition of polyaniline on the redox sites of IC-DDT SAM using electrochemical polymerization of aniline was performed in order to confirm that this monolayer acts as nano-patterned semiconducting electrode surface.

  1. Near-optimality of special periodic protocols for fluid models of single server switched networks with switchover times

    Science.gov (United States)

    Matveev, A. S.; Ishchenko, R.

    2017-11-01

    We consider a generic deterministic time-invariant fluid model of a single server switched network, which consists of finitely many infinite size buffers (queues) and receives constant rate inflows of jobs from the outside. Any flow undergoes a multi-phase service, entering a specific buffer after every phase, and ultimately leaves the network; the route of the flow over the buffers is pre-specified, and flows may merge inside the network. They share a common source of service, which can serve at most one buffer at a time and has to switch among buffers from time to time; any switch consumes a nonzero switchover period. With respect to the long-run maximal scaled wip (work in progress) performance metric, near-optimality of periodic scheduling and service protocols is established: the deepest optimum (that is over all feasible processes in the network, irrespective of the initial state) is furnished by such a protocol up to as small error as desired. Moreover, this can be achieved with a special periodic protocol introduced in the paper. It is also shown that the exhaustive policy is optimal for any buffer whose service at the maximal rate does not cause growth of the scaled wip.

  2. All-optical header recognizer for optical packet switched networks : exploiting nonlinear gain and index dynamics in semiconductor optical amplifiers for low power operation and photonic integration device

    NARCIS (Netherlands)

    Calabretta, N.; Dorren, H.J.S.

    2009-01-01

    The increase of the internet traffic leads to future optical networks requiring tens of Tb/s of capacity. Current electronic circuit switches are limited by the scalability of the electronic switching fabrics, power consumption and dissipation in the opto- electronic conversion. All-optical packet

  3. A study on the growth of compound semiconductor single crystal by TOM technique

    International Nuclear Information System (INIS)

    Kim, H.C.; Kwon, S.I.; Chung, M.K.; Chang, J.S.

    1981-01-01

    This paper describes the merit of the HgI 2 single crystals obtained by solution growth, 2- and 3-region temperature growth, and temperature oscillation growth for soft γ-ray detectors which can be operated at room temperature. Special efforts are put on the design, construction, and operation of the TOM (Temperature Oscillation Method) single crystal growing furnace. Experimental results show that HgI 2 detectors fabricated by vapour phase growth method usually exhibit sufficient enough detector characteristics for soft γ-ray spectrometry. However, further investigation should be carried out to eliminate detector deterioration due to polarization effect. (author)

  4. Super-Resolution Definition of Coordinates of Single Semiconductor Nanocrystal (Quantum Dot: Luminescence Intensity Dependence

    Directory of Open Access Journals (Sweden)

    Eremchev M. Yu.

    2015-01-01

    Full Text Available In this research a relation between the accuracy of restoration of the single quantum dots (QD CdSe/CdS/ZnS cross-cut coordinates and luminescence intensity was investigated. It was shown that the limit of the accuracy of determining the coordinates of a single QD for a considerable total amount of registered photons approaches its limiting value that is comparable to the size of the QD. It also means that the installation used in the research is mechanically stable enough to reach the limiting values of determination accuracy of point emitters coordinates.

  5. Electronic properties of semiconductor heterostructures

    International Nuclear Information System (INIS)

    Einevoll, G.T.

    1991-02-01

    Ten papers on the electronic properties of semiconductors and semiconductor heterostructures constitute the backbone of this thesis. Four papers address the form and validity of the single-band effective mass approximation for semiconductor heterostructures. In four other papers properties of acceptor states in bulk semiconductors and semiconductor heterostructures are studied using the novel effective bond-orbital model. The last two papers deal with localized excitions. 122 refs

  6. Doppler wind lidar using a MOPA semiconductor laser at stable single-frequency operation

    DEFF Research Database (Denmark)

    Rodrigo, Peter John; Pedersen, Christian

    2009-01-01

    for the tapered amplifier section. The specified maximum current values are 0.7 A and 4.0 A for Idfb and Iamp. Although the MOPA-SL has been proven capable of producing single-frequency CW output beam, stable operation at this spectral condition has also been known to highly depend on the drive currents...

  7. Single Event Effects (SEE) for Power Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs)

    Science.gov (United States)

    Lauenstein, Jean-Marie

    2011-01-01

    Single-event gate rupture (SEGR) continues to be a key failure mode in power MOSFETs. (1) SEGR is complex, making rate prediction difficult SEGR mechanism has two main components: (1) Oxide damage-- Reduces field required for rupture (2) Epilayer response -- Creates transient high field across the oxide.

  8. An important rule for realizing metal → half-metal → semiconductor transition in single-molecule junctions

    Science.gov (United States)

    Zeng, Jing; Chen, Ke-Qiu; Long, Mengqiu

    2017-06-01

    Recently, Zhong et al (2015 Nano Lett. 15 8091) found that two additional hydrogen atoms can be adsorbed to the opposite aza-bridging nitrogen atoms of the manganese phthalocyanine (MnPc) macrocycle when exposed to H2. Thus the symmetry of the MnPc molecule is changed from 4-fold to 2-fold. Motivated by this recent experiment, we theoretically investigate a MnPc-based single-molecule junction in this work and propose a simple and reliable way to realize the transition of its electronic properties. On the basis of spin-polarized density-functional theory calculations combined with the Keldysh nonequilibrium Green’s technique, we find that the gradual hydrogenation in MnPc molecules gives rise to the changes of the hardness of the electron density and spin-selective orbital decoupling, which eventually leads to the realization of the first ever metal  →  half-metal  →  semiconductor transition behavior in single-molecule junctions. Analysis of molecular projected self-consistent Hamiltonian, Mulliken population, and local density of states also reveals an important rule for realizing this transition behavior. Our research confirms that the hydrogenation of MnPc molecules can realize various molecular functionalities in unitary material background.

  9. An important rule for realizing metal → half-metal → semiconductor transition in single-molecule junctions

    International Nuclear Information System (INIS)

    Zeng, Jing; Chen, Ke-Qiu; Long, Mengqiu

    2017-01-01

    Recently, Zhong et al (2015 Nano Lett . 15 8091) found that two additional hydrogen atoms can be adsorbed to the opposite aza-bridging nitrogen atoms of the manganese phthalocyanine (MnPc) macrocycle when exposed to H 2 . Thus the symmetry of the MnPc molecule is changed from 4-fold to 2-fold. Motivated by this recent experiment, we theoretically investigate a MnPc-based single-molecule junction in this work and propose a simple and reliable way to realize the transition of its electronic properties. On the basis of spin-polarized density-functional theory calculations combined with the Keldysh nonequilibrium Green’s technique, we find that the gradual hydrogenation in MnPc molecules gives rise to the changes of the hardness of the electron density and spin-selective orbital decoupling, which eventually leads to the realization of the first ever metal  →  half-metal  →  semiconductor transition behavior in single-molecule junctions. Analysis of molecular projected self-consistent Hamiltonian, Mulliken population, and local density of states also reveals an important rule for realizing this transition behavior. Our research confirms that the hydrogenation of MnPc molecules can realize various molecular functionalities in unitary material background. (paper)

  10. Single-event phenomena on recent semiconductor devices. Charge-type multiple-bit upsets in high integrated memories

    International Nuclear Information System (INIS)

    Makihara, Akiko; Shindou, Hiroyuki; Nemoto, Norio; Kuboyama, Satoshi; Matsuda, Sumio; Ohshima, Takeshi; Hirao, Toshio; Itoh, Hisayoshi

    2001-01-01

    High integrated memories are used in solid state data recorder (SSDR) of the satellite for accumulating observation data. Single event upset phenomena which turn over an accumulated data in the memory cells are caused by heavy ion incidence. Studies on single-bit upset and multiple-bit upset phenomena in the high integrated memory cells are in progress recently. 16 Mbit DRAM (Dynamic Random Access Memories) and 64 Mbit DRAM are irradiated by heavy ion species, such as iodine, bromine and nickel, in comparison with the irradiation damage in the cosmic environment. Data written on the memory devices are read out after the irradiation. The memory cells in three kinds of states, all of charged state, all of discharged state, and an alternative state of charge and discharge, are irradiated for sorting out error modes caused by heavy ion incidence. The soft error in a single memory cells is known as a turn over from charged state to discharged state. Electrons in electron-hole pair generated by heavy ion incidence are captured in a diffusion region between capacitor electrodes of semiconductor. The charged states in the capacitor electrodes before the irradiation are neutralized and changed to the discharged states. According to high integration of the memories, many of the cells are affected by a single ion incidence. The multiple-bit upsets, however, are generated in the memory cells of discharged state before the irradiation, also. The charge-type multiple-bit upsets is considered as that error data are written on the DRAM during refresh cycle of a sense-up circuit and a pre-charge circuit which control the DRAM. (M. Suetake)

  11. Sensorless control of low-cost single-phase hybrid switched reluctance motor drive

    DEFF Research Database (Denmark)

    Jakobsen, Uffe; Lu, Kaiyuan; Rasmussen, Peter Omand

    2013-01-01

    This paper presents a sensorless-controlled, low-cost, low-power, variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor...... is a special Hybrid Switched Reluctance Motor (HSRM). The proposed sensorless control method utilizes beneficially the stator side permanent magnet field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive...

  12. Sensorless Control of Low-cost Single-phase Hybrid Switched Reluctance Motor Drive

    DEFF Research Database (Denmark)

    Jakobsen, Uffe; Lu, Kaiyuan; Rasmussen, Peter Omand

    2015-01-01

    This paper presents a sensorless-controlled, low-cost, low-power, and variable-speed drive system suitable for fan and pump applications. The main advantages of this drive system are the low system cost, simple converter structure, and simple but robust sensorless control technique. The drive motor...... is a special hybrid switched reluctance motor. The proposed sensorless control method beneficially utilizes the stator side PM field and its performance is motor parameter independent. The unique low-cost drive system solution, simple and robust sensorless control features of this drive system, is demonstrated...

  13. Single Photon, Spin, and Charge in Diamond Semiconductor at room temperature

    International Nuclear Information System (INIS)

    Yuki Doi

    2014-01-01

    The nitrogen-vacancy (NV) center in diamond is a promising candidate for a qubit driven at room temperature. In order to derive potential of NV center, manipulation of their charge state is a very important topic. Here we succeeded to electrically control between single NV-/NV0 by means of current injection. This method allows us to very stable charge state control. (author)

  14. Design comparison of single phase outer and inner-rotor hybrid excitation flux switching motor for hybrid electric vehicles

    Science.gov (United States)

    Mazlan, Mohamed Mubin Aizat; Sulaiman, Erwan; Husin, Zhafir Aizat; Othman, Syed Muhammad Naufal Syed; Khan, Faisal

    2015-05-01

    In hybrid excitation machines (HEMs), there are two main flux sources which are permanent magnet (PM) and field excitation coil (FEC). These HEMs have better features when compared with the interior permanent magnet synchronous machines (IPMSM) used in conventional hybrid electric vehicles (HEVs). Since all flux sources including PM, FEC and armature coils are located on the stator core, the rotor becomes a single piece structure similar with switch reluctance machine (SRM). The combined flux generated by PM and FEC established more excitation fluxes that are required to produce much higher torque of the motor. In addition, variable DC FEC can control the flux capabilities of the motor, thus the machine can be applied for high-speed motor drive system. In this paper, the comparisons of single-phase 8S-4P outer and inner rotor hybrid excitation flux switching machine (HEFSM) are presented. Initially, design procedures of the HEFSM including parts drawing, materials and conditions setting, and properties setting are explained. Flux comparisons analysis is performed to investigate the flux capabilities at various current densities. Then the flux linkages of PM with DC FEC of various DC FEC current densities are examined. Finally torque performances are analyzed at various armature and FEC current densities for both designs. As a result, the outer-rotor HEFSM has higher flux linkage of PM with DC FEC and higher average torque of approximately 10% when compared with inner-rotor HEFSM.

  15. Q-switching and efficient harmonic generation from a single-mode LMA photonic bandgap rod fiber laser

    DEFF Research Database (Denmark)

    Laurila, Marko; Saby, Julien; Alkeskjold, Thomas T.

    2011-01-01

    We demonstrate a Single-Mode (SM) Large-Mode-Area (LMA) ytterbium-doped PCF rod fiber laser with stable and close to diffraction limited beam quality with 110W output power. Distributed-Mode-Filtering (DMF) elements integrated in the cladding of the rod fiber provide a robust spatial mode...... with a Mode-Field-Diameter (MFD) of 59 mu m. We further demonstrate high pulse energy Second-Harmonic-Generation (SHG) and Third Harmonic Generation (THG) using a simple Q-switched single-stage rod fiber laser cavity architecture reaching pulse energies up to 1mJ at 515nm and 0.5mJ at 343nm. (C) 2011 Optical...

  16. Single event upsets in semiconductor devices induced by highly ionising particles.

    Science.gov (United States)

    Sannikov, A V

    2004-01-01

    A new model of single event upsets (SEUs), created in memory cells by heavy ions and high energy hadrons, has been developed. The model takes into account the spatial distribution of charge collection efficiency over the cell area not considered in previous approaches. Three-dimensional calculations made by the HADRON code have shown good agreement with experimental data for the energy dependence of proton SEU cross sections, sensitive depths and other SEU observables. The model is promising for prediction of SEU rates for memory chips exposed in space and in high-energy experiments as well as for the development of a high-energy neutron dosemeter based on the SEU effect.

  17. Single Ion transient-IBIC analyses of semiconductor devices using a cryogenic temperature stage

    International Nuclear Information System (INIS)

    Laird, J.S.; Bardos, R.; Legge, G.J.F.; Jagadish, C.

    1998-01-01

    A new Transient - IBIC data acquisition and analysis system at MARC is described. A discussion on the need for single ion control and temperature control is also given. The recorded signal is used as the trigger for beam pulsing. The new cryostatic temperature control stage is introduced. Data is presented on line profiles across the edge of a Au-Si junction collected over the temperature range of 25-300K using a developed C-V and I-V variable temperature stage incorporating a liquid helium cryostat. It demonstrates the potential improvements in spatial resolution in materials of long lifetime by mapping on timing windows around the prompt charge component in the charge transient

  18. Semiconductor laser engineering, reliability and diagnostics a practical approach to high power and single mode devices

    CERN Document Server

    Epperlein, Peter W

    2013-01-01

    This reference book provides a fully integrated novel approach to the development of high-power, single-transverse mode, edge-emitting diode lasers by addressing the complementary topics of device engineering, reliability engineering and device diagnostics in the same book, and thus closes the gap in the current book literature. Diode laser fundamentals are discussed, followed by an elaborate discussion of problem-oriented design guidelines and techniques, and by a systematic treatment of the origins of laser degradation and a thorough exploration of the engineering means to enhance the optical strength of the laser. Stability criteria of critical laser characteristics and key laser robustness factors are discussed along with clear design considerations in the context of reliability engineering approaches and models, and typical programs for reliability tests and laser product qualifications. Novel, advanced diagnostic methods are reviewed to discuss, for the first time in detail in book literature, performa...

  19. Room temperature ferromagnetism in Fe-doped semiconductor ZrS2 single crystals

    Science.gov (United States)

    Muhammad, Zahir; Lv, Haifeng; Wu, Chuanqiang; Habib, Muhammad; Rehman, Zia ur; Khan, Rashid; Chen, Shuangming; Wu, Xiaojun; Song, Li

    2018-04-01

    Two dimensional (2D) layered magnetic materials have obtained much attention due to their intriguing properties with a potential application in the field of spintronics. Herein, room-temperature ferromagnetism with 0.2 emu g‑1 magnetic moment is realized in Fe-doped ZrS2 single crystals of millimeter size, in comparison with diamagnetic behaviour in ZrS2. The electron paramagnetic resonance spectroscopy reveals that 5.2wt% Fe-doping ZrS2 crystal exhibit high spin value of g-factor about 3.57 at room temperature also confirmed this evidence, due to the unpaired electrons created by doped Fe atoms. First principle static electronic and magnetic calculations further confirm the increased stability of long range ferromagnetic ordering and enhanced magnetic moment in Fe-doped ZrS2, originating from the Fe spin polarized electron near the Fermi level.

  20. MCT/MOSFET Switch

    Science.gov (United States)

    Rippel, Wally E.

    1990-01-01

    Metal-oxide/semiconductor-controlled thyristor (MCT) and metal-oxide/semiconductor field-effect transistor (MOSFET) connected in switching circuit to obtain better performance. Offers high utilization of silicon, low forward voltage drop during "on" period of operating cycle, fast turnon and turnoff, and large turnoff safe operating area. Includes ability to operate at high temperatures, high static blocking voltage, and ease of drive.

  1. Initiation of explosive conversions in energy-saturated nanoporous silicon-based compounds with fast semiconductor switches and energy-releasing elements

    Science.gov (United States)

    Savenkov, G. G.; Kardo-Sysoev, A. F.; Zegrya, A. G.; Os'kin, I. A.; Bragin, V. A.; Zegrya, G. G.

    2017-10-01

    The first findings concerning the initiation of explosive conversions in energy-saturated nanoporous silicon-based compounds via the electrical explosion of a semiconductor bridge are presented. The obtained results indicate that the energy parameters of an explosive conversion depend on the mass of a combustible agent—namely, nanoporous silicon—and the silicon-doping type.

  2. Intrinsic nanofilamentation in resistive switching

    KAUST Repository

    Wu, Xing; Cha, Dong Kyu; Bosman, Michel; Raghavan, Nagarajan; Migas, Dmitri B.; Borisenko, Victor E.; Zhang, Xixiang; Li, Kun; Pey, Kin-Leong

    2013-01-01

    -chip circuitry and non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive switching via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission

  3. Single-photon semiconductor photodiodes for distributed optical fiber sensors: state of the art and perspectives

    Science.gov (United States)

    Ripamonti, Giancarlo; Lacaita, Andrea L.

    1993-03-01

    The extreme sensitivity and time resolution of Geiger-mode avalanche photodiodes (GM- APDs) have already been exploited for optical time domain reflectometry (OTDR). Better than 1 cm spatial resolution in Rayleigh scattering detection was demonstrated. Distributed and quasi-distributed optical fiber sensors can take advantage of the capabilities of GM-APDs. Extensive studies have recently disclosed the main characteristics and limitations of silicon devices, both commercially available and developmental. In this paper we report an analysis of the performance of these detectors. The main characteristics of GM-APDs of interest for distributed optical fiber sensors are briefly reviewed. Command electronics (active quenching) is then introduced. The detector timing performance sets the maximum spatial resolution in experiments employing OTDR techniques. We highlight that the achievable time resolution depends on the physics of the avalanche spreading over the device area. On the basis of these results, trade-off between the important parameters (quantum efficiency, time resolution, background noise, and afterpulsing effects) is considered. Finally, we show first results on Germanium devices, capable of single photon sensitivity at 1.3 and 1.5 micrometers with sub- nanosecond time resolution.

  4. Impacts of Coulomb Interactions on the Magnetic Responses of Excitonic Complexes in Single Semiconductor Nanostructures

    Directory of Open Access Journals (Sweden)

    Fu Ying-Jhe

    2010-01-01

    Full Text Available Abstract We report on the diamagnetic responses of different exciton complexes in single InAs/GaAs self-assembled quantum dots (QDs and quantum rings (QRs. For QDs, the imbalanced magnetic responses of inter-particle Coulomb interactions play a crucial role in the diamagnetic shifts of excitons (X, biexcitons (XX, and positive trions (X−. For negative trions (X− in QDs, anomalous magnetic responses are observed, which cannot be described by the conventional quadratic energy shift with the magnetic field. The anomalous behavior is attributed to the apparent change in the electron wave function extent after photon emission due to the strong Coulomb attraction by the hole in its initial state. In QRs, the diamagnetic responses of X and XX also show different behaviors. Unlike QDs, the diamagnetic shift of XX in QRs is considerably larger than that of X. The inherent structural asymmetry combined with the inter-particle Coulomb interactions makes the wave function distribution of XX very different from that of X in QRs. Our results suggest that the phase coherence of XX in QRs may survive from the wave function localization due to the structural asymmetry or imperfections.

  5. Nano-optical observation of cascade switching in a parallel superconducting nanowire single photon detector

    International Nuclear Information System (INIS)

    Heath, Robert M.; Tanner, Michael G.; Casaburi, Alessandro; Hadfield, Robert H.; Webster, Mark G.; San Emeterio Alvarez, Lara; Jiang, Weitao; Barber, Zoe H.; Warburton, Richard J.

    2014-01-01

    The device physics of parallel-wire superconducting nanowire single photon detectors is based on a cascade process. Using nano-optical techniques and a parallel wire device with spatially separate pixels, we explicitly demonstrate the single- and multi-photon triggering regimes. We develop a model for describing efficiency of a detector operating in the arm-trigger regime. We investigate the timing response of the detector when illuminating a single pixel and two pixels. We see a change in the active area of the detector between the two regimes and find the two-pixel trigger regime to have a faster timing response than the one-pixel regime

  6. Active and fast charge-state switching of single NV centres in diamond by in-plane Al-Schottky junctions

    Directory of Open Access Journals (Sweden)

    Christoph Schreyvogel

    2016-11-01

    Full Text Available In this paper, we demonstrate an active and fast control of the charge state and hence of the optical and electronic properties of single and near-surface nitrogen-vacancy centres (NV centres in diamond. This active manipulation is achieved by using a two-dimensional Schottky-diode structure from diamond, i.e., by using aluminium as Schottky contact on a hydrogen terminated diamond surface. By changing the applied potential on the Schottky contact, we are able to actively switch single NV centres between all three charge states NV+, NV0 and NV− on a timescale of 10 to 100 ns, corresponding to a switching frequency of 10–100 MHz. This switching frequency is much higher than the hyperfine interaction frequency between an electron spin (of NV− and a nuclear spin (of 15N or 13C for example of 2.66 kHz. This high-frequency charge state switching with a planar diode structure would open the door for many quantum optical applications such as a quantum computer with single NVs for quantum information processing as well as single 13C atoms for long-lifetime storage of quantum information. Furthermore, a control of spectral emission properties of single NVs as a single photon emitters – embedded in photonic structures for example – can be realized which would be vital for quantum communication and cryptography.

  7. Single molecule localization imaging of telomeres and centromeres using fluorescence in situ hybridization and semiconductor quantum dots.

    Science.gov (United States)

    Wang, Le; Zong, Shenfei; Wang, Zhuyuan; Lu, Ju; Chen, Chen; Zhang, Ruohu; Cui, Yiping

    2018-07-13

    Single molecule localization microscopy (SMLM) is a powerful tool for imaging biological targets at the nanoscale. In this report, we present SMLM imaging of telomeres and centromeres using fluorescence in situ hybridization (FISH). The FISH probes were fabricated by decorating CdSSe/ZnS quantum dots (QDs) with telomere or centromere complementary DNA strands. SMLM imaging experiments using commercially available peptide nucleic acid (PNA) probes labeled with organic fluorophores were also conducted to demonstrate the advantages of using QDs FISH probes. Compared with the PNA probes, the QDs probes have the following merits. First, the fluorescence blinking of QDs can be realized in aqueous solution or PBS buffer without thiol, which is a key buffer component for organic fluorophores' blinking. Second, fluorescence blinking of the QDs probe needs only one excitation light (i.e. 405 nm). While fluorescence blinking of the organic fluorophores usually requires two illumination lights, that is, the activation light (i.e. 405 nm) and the imaging light. Third, the high quantum yield, multiple switching times and a good optical stability make the QDs more suitable for long-term imaging. The localization precision achieved in telomeres and centromeres imaging experiments is about 30 nm, which is far beyond the diffraction limit. SMLM has enabled new insights into telomeres or centromeres on the molecular level, and it is even possible to determine the length of telomere and become a potential technique for telomere-related investigation.

  8. Enhancing the x-ray output of a single-wire explosion with a gas-puff based plasma opening switch

    Science.gov (United States)

    Engelbrecht, Joseph T.; Ouart, Nicholas D.; Qi, Niansheng; de Grouchy, Philip W.; Shelkovenko, Tatiana A.; Pikuz, Sergey A.; Banasek, Jacob T.; Potter, William M.; Rocco, Sophia V.; Hammer, David A.; Kusse, Bruce R.; Giuliani, John L.

    2018-02-01

    We present experiments performed on the 1 MA COBRA generator using a low density, annular, gas-puff z-pinch implosion as an opening switch to rapidly transfer a current pulse into a single metal wire on axis. This gas-puff on axial wire configuration was studied for its promise as an opening switch and as a means of enhancing the x-ray output of the wire. We demonstrate that current can be switched from the gas-puff plasma into the wire, and that the timing of the switch can be controlled by the gas-puff plenum backing pressure. X-ray detector measurements indicate that for low plenum pressure Kr or Xe shots with a copper wire, this configuration can offer a significant enhancement in the peak intensity and temporal distribution of radiation in the 1-10 keV range.

  9. Temperature persistent bistability and threshold switching in a single barrier heterostructure hot-electron diode

    DEFF Research Database (Denmark)

    Stasch, R.; Hey, R.; Asche, M.

    1996-01-01

    Bistable current–voltage characteristics caused by competition of tunneling through and field-enhanced thermionic emission across a single barrier are investigated in an n–-GaAs/Al0.34Ga0.66As/n+-GaAs structure. The S-shaped part of the characteristic persists in the whole temperature regime...

  10. A single molecule switch based on two Pd nanocrystals linked by a ...

    Indian Academy of Sciences (India)

    in this single molecule system. 2. Experimental ... (b) Histogram showing size distribution of the nanocrystal in (a). (c) Micro- graph taken ... applied on one of the nanocrystals using the STM tip, a voltage drop is expected along the molecular ...

  11. Atomic switches: atomic-movement-controlled nanodevices for new types of computing

    International Nuclear Information System (INIS)

    Hino, Takami; Hasegawa, Tsuyoshi; Terabe, Kazuya; Tsuruoka, Tohru; Nayak, Alpana; Ohno, Takeo; Aono, Masakazu

    2011-01-01

    Atomic switches are nanoionic devices that control the diffusion of metal cations and their reduction/oxidation processes in the switching operation to form/annihilate a metal atomic bridge, which is a conductive path between two electrodes in the on-state. In contrast to conventional semiconductor devices, atomic switches can provide a highly conductive channel even if their size is of nanometer order. In addition to their small size and low on-resistance, their nonvolatility has enabled the development of new types of programmable devices, which may achieve all the required functions on a single chip. Three-terminal atomic switches have also been developed, in which the formation and annihilation of a metal atomic bridge between a source electrode and a drain electrode are controlled by a third (gate) electrode. Three-terminal atomic switches are expected to enhance the development of new types of logic circuits, such as nonvolatile logic. The recent development of atomic switches that use a metal oxide as the ionic conductive material has enabled the integration of atomic switches with complementary metal-oxide-semiconductor (CMOS) devices, which will facilitate the commercialization of atomic switches. The novel characteristics of atomic switches, such as their learning and photosensing abilities, are also introduced in the latter part of this review. (topical review)

  12. Complementary resistive switching in BaTiO{sub 3}/NiO bilayer with opposite switching polarities

    Energy Technology Data Exchange (ETDEWEB)

    Li, Shuo [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Institut d’Electronique de Micro-électronique et de Nanotechnologie (IEMN), CNRS, Université des Sciences et Technologies de Lille, avenue Poincaré, BP 60069, 59652, Villeneuve d’Ascq cedex (France); Wei, Xianhua, E-mail: weixianhua@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Lei, Yao [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu 610054 (China); Yuan, Xincai [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, Southwest University of Science and Technology, Mianyang 621010 (China); Zeng, Huizhong [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronics Science and Technology of China, Chengdu 610054 (China)

    2016-12-15

    Graphical abstract: Au/BaTiO{sub 3}/NiO/Pt bilayer device shows complementary resistive switching (CRS) without electroforming which is mainly ascribed to anti-serial stack of two RRAM cells with bipolar behaviors. - Highlights: • Complementary resistive switching (CRS) has been investigated in Au/BaTiO{sub 3}/NiO/Pt by stacking the two elements with different switching types. • The realization of complementary resistive switching (CRS) is mainly ascribed to the anti-serial stack of two RRAM cells with bipolar behaviors. • Complementary resistive switching (CRS) in bilayer is effective to solve the sneak current problem briefly and economically. - Abstract: Resistive switching behaviors have been investigated in the Au/BaTiO{sub 3}/NiO/Pt structure by stacking the two elements with different switching types. The conducting atomic force microscope measurements on BaTiO{sub 3} thin films and NiO thin films suggest that with the same active resistive switching region, the switching polarities in the two semiconductors are opposite to each other. It is in agreement with the bipolar hysteresis I–V curves with opposite switching polarities for single-layer devices. The bilayer devices show complementary resistive switching (CRS) without electroforming and unipolar resistive switching (URS) after electroforming. The coexistence of CRS and URS is mainly ascribed to the co-effect of electric field and Joule heating mechanisms, indicating that changeable of resistance in this device is dominated by the redistribution of oxygen vacancies in BaTiO{sub 3} and the formation, disruption, restoration of conducting filaments in NiO. CRS in bilayer with opposite switching polarities is effective to solve the sneak current without the introduction of any selector elements or an additional metal electrode.

  13. Test Standard Revision Update: JESD57, "Procedures for the Measurement of Single-Event Effects in Semiconductor Devices from Heavy-Ion Irradiation"

    Science.gov (United States)

    Lauenstein, Jean-Marie

    2015-01-01

    The JEDEC JESD57 test standard, Procedures for the Measurement of Single-Event Effects in Semiconductor Devices from Heavy-Ion Irradiation, is undergoing its first revision since 1996. In this talk, we place this test standard into context with other relevant radiation test standards to show its importance for single-event effect radiation testing for space applications. We show the range of industry, government, and end-user party involvement in the revision. Finally, we highlight some of the key changes being made and discuss the trade-space in which setting standards must be made to be both useful and broadly adopted.

  14. Bias voltage induced resistance switching effect in single-molecule magnets' tunneling junction.

    Science.gov (United States)

    Zhang, Zhengzhong; Jiang, Liang

    2014-09-12

    An electric-pulse-induced reversible resistance change effect in a molecular magnetic tunneling junction, consisting of a single-molecule magnet (SMM) sandwiched in one nonmagnetic and one ferromagnetic electrode, is theoretically investigated. By applying a time-varying bias voltage, the SMM's spin orientation can be manipulated with large bias voltage pulses. Moreover, the different magnetic configuration at high-resistance/low-resistance states can be 'read out' by utilizing relative low bias voltage. This device scheme can be implemented with current technologies (Khajetoorians et al 2013 Science 339 55) and has potential application in molecular spintronics and high-density nonvolatile memory devices.

  15. Bias voltage induced resistance switching effect in single-molecule magnets’ tunneling junction

    Science.gov (United States)

    Zhang, Zhengzhong; Jiang, Liang

    2014-09-01

    An electric-pulse-induced reversible resistance change effect in a molecular magnetic tunneling junction, consisting of a single-molecule magnet (SMM) sandwiched in one nonmagnetic and one ferromagnetic electrode, is theoretically investigated. By applying a time-varying bias voltage, the SMM's spin orientation can be manipulated with large bias voltage pulses. Moreover, the different magnetic configuration at high-resistance/low-resistance states can be ‘read out’ by utilizing relative low bias voltage. This device scheme can be implemented with current technologies (Khajetoorians et al 2013 Science 339 55) and has potential application in molecular spintronics and high-density nonvolatile memory devices.

  16. Switching features of GMO single crystals by contrary motion of pair planar domain boundaries

    International Nuclear Information System (INIS)

    Alekseev, A.N.

    2003-01-01

    Gadolinium molybdate single crystal specimens in the form of square plates 1.2 mm thick, which provide similar conditions of nucleation of domains with differently oriented planar domain boundaries (PDB), are used to study processes of total change-over of orientation states by compressing mechanical action applied alternately to one of two pairs of opposite end faces of the specimen. It is revealed that successive acts of such change-over are always carried out by PDB pairs of alternating mutually orthogonal orientation. A closing stage for every successive change-over is realized through a collapse of either wedge-like or lenticular domain [ru

  17. A single mutation in Taiwanese H6N1 influenza hemagglutinin switches binding to human-type receptors

    Energy Technology Data Exchange (ETDEWEB)

    de Vries, Robert P.; Tzarum, Netanel; Peng, Wenjie; Thompson, Andrew J.; Ambepitiya Wickramasinghe, Iresha N.; de la Pena, Alba T. Torrents; van Breemen, Marielle J.; Bouwman, Kim M.; Zhu, Xueyong; McBride, Ryan; Yu, Wenli; Sanders, Rogier W.; Verheije, Monique H.; Wilson, Ian A.; Paulson, James C.

    2017-07-10

    In June 2013, the first case of human infection with an avian H6N1 virus was reported in a Taiwanese woman. Although this was a single non-fatal case, the virus continues to circulate in Taiwanese poultry. As with any emerging avian virus that infects humans, there is concern that acquisition of human-type receptor specificity could enable transmission in the human population. Despite mutations in the receptor-binding pocket of the human H6N1 isolate, it has retained avian-type (NeuAcα2-3Gal) receptor specificity. However, we show here that a single nucleotide substitution, resulting in a change from Gly to Asp at position 225 (G225D), completely switches specificity to human-type (NeuAcα2-6Gal) receptors. Significantly, G225D H6 loses binding to chicken trachea epithelium and is now able to bind to human tracheal tissue. Structural analysis reveals that Asp225 directly interacts with the penultimate Gal of the human-type receptor, stabilizing human receptor binding.

  18. Analysis of trace inorganic anions in weak acid salts by single pump cycling-column-switching ion chromatography.

    Science.gov (United States)

    Huang, Zhongping; Ni, Chengzhu; Zhu, Zhuyi; Pan, Zaifa; Wang, Lili; Zhu, Yan

    2015-05-01

    The application of ion chromatography with the single pump cycling-column-switching technique was described for the analysis of trace inorganic anions in weak acid salts within a single run. Due to the hydrogen ions provided by an anion suppressor electrolyzing water, weak acid anions could be transformed into weak acids, existing as molecules, after passing through the suppressor. Therefore, an anion suppressor and ion-exclusion column were adopted to achieve on-line matrix elimination of weak acid anions with high concentration for the analysis of trace inorganic anions in weak acid salts. A series of standard solutions consisting of target anions of various concentrations from 0.005 to 10 mg/L were analyzed, with correlation coefficients r ≥ 0.9990. The limits of detection were in the range of 0.67 to 1.51 μg/L, based on the signal-to-noise ratio of 3 and a 25 μL injection volume. Relative standard deviations for retention time, peak area, and peak height were all less than 2.01%. A spiking study was performed with satisfactory recoveries between 90.3 and 104.4% for all anions. The chromatographic system was successfully applied to the analysis of trace inorganic anions in five weak acid salts. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Practical switching power supply design

    CERN Document Server

    Brown, Martin C

    1990-01-01

    Take the ""black magic"" out of switching power supplies with Practical Switching Power Supply Design! This is a comprehensive ""hands-on"" guide to the theory behind, and design of, PWM and resonant switching supplies. You'll find information on switching supply operation and selecting an appropriate topology for your application. There's extensive coverage of buck, boost, flyback, push-pull, half bridge, and full bridge regulator circuits. Special attention is given to semiconductors used in switching supplies. RFI/EMI reduction, grounding, testing, and safety standards are also deta

  20. Single-walled carbon nanotube electromechanical switching behavior with shoulder slip

    Science.gov (United States)

    Ryan, Peter; Wu, Yu-Chiao; Somu, Sivasubramanian; Adams, George; McGruer, Nicol

    2011-04-01

    Several electromechanical devices, each consisting of a small bundle of single-walled carbon nanotubes suspended over an actuation electrode, have been fabricated and operated electrically. The nanotubes are assembled on the electrodes using dielectrophoresis, a potential high-rate nanomanufacturing process. A large decrease in the threshold voltage was seen after the first actuation. This is a result of the nanotubes sliding inward on their supports as they are pulled down toward the actuation electrode, leaving slack in the nanotube bundle for subsequent actuations. The electrical measurements agree well with an electromechanical model that uses a literature-reported value of the shear stress between the nanotubes and the SiO2 shoulders. Electrical measurements were performed in dry nitrogen as a large build-up of contamination was seen when the measurements were performed in lab air. We present measurements as well as a detailed mechanics model that support the interpretation of the data.

  1. Single-walled carbon nanotube electromechanical switching behavior with shoulder slip

    International Nuclear Information System (INIS)

    Ryan, Peter; Wu, Yu-Chiao; Somu, Sivasubramanian; Adams, George; McGruer, Nicol

    2011-01-01

    Several electromechanical devices, each consisting of a small bundle of single-walled carbon nanotubes suspended over an actuation electrode, have been fabricated and operated electrically. The nanotubes are assembled on the electrodes using dielectrophoresis, a potential high-rate nanomanufacturing process. A large decrease in the threshold voltage was seen after the first actuation. This is a result of the nanotubes sliding inward on their supports as they are pulled down toward the actuation electrode, leaving slack in the nanotube bundle for subsequent actuations. The electrical measurements agree well with an electromechanical model that uses a literature-reported value of the shear stress between the nanotubes and the SiO 2 shoulders. Electrical measurements were performed in dry nitrogen as a large build-up of contamination was seen when the measurements were performed in lab air. We present measurements as well as a detailed mechanics model that support the interpretation of the data.

  2. Adrenal incidentaloma triage with single source (fast kVp switch) dual energy CT

    Science.gov (United States)

    Glazer, Daniel I; Keshavarzi, Nahid R; Parker, Robert A; Kaza, Ravi K; Platt, Joel F; Francis, Isaac R

    2015-01-01

    Purpose To evaluate single source dual energy CT (DECT) for distinguishing benign and indeterminate adrenal nodules, with attention to effects of phase of intravenous contrast enhancement. Materials and methods An IRB-approved, HIPAA-compliant retrospective review revealed 273 contrast-enhanced abdominal DECTs from November 2009–March 2012. 50 adrenal nodules ≥ 0.8 cm were identified in 41 patients: 22 female, 19 male, average age 66 (range 36–88 years). CT post-processing and measurements were independently performed by two radiologists (R1 and R2) for each nodule: (1) HU on true non-contrast images; (2) post-contrast HU on monochromatic spectral images at 40, 75, and 140 keV; (3) post-contrast material density (mg/cc) on virtual non-contrast (VNC) images. Nodules were separated into benign (VNC images, benign nodules had significantly lower material density (R1: 992.4 mg/cc ± 9.9; R2: 992.7 mg/cc ±9.6) than indeterminate nodules (R1: 1001.1mg/cc ±20.5 (p .038); R2: 1007.6 HU ±13.4 (p <.0001). Conclusion DECT tools can mathematically subtract iodine or minimize its effects in high energy reconstructions, approximating non-contrast imaging and potentially reducing the need for additional studies to triage adrenal nodules detected on post-contrast DECT exams. PMID:25055267

  3. Complementary resistive switching in BaTiO3/NiO bilayer with opposite switching polarities

    Science.gov (United States)

    Li, Shuo; Wei, Xianhua; Lei, Yao; Yuan, Xincai; Zeng, Huizhong

    2016-12-01

    Resistive switching behaviors have been investigated in the Au/BaTiO3/NiO/Pt structure by stacking the two elements with different switching types. The conducting atomic force microscope measurements on BaTiO3 thin films and NiO thin films suggest that with the same active resistive switching region, the switching polarities in the two semiconductors are opposite to each other. It is in agreement with the bipolar hysteresis I-V curves with opposite switching polarities for single-layer devices. The bilayer devices show complementary resistive switching (CRS) without electroforming and unipolar resistive switching (URS) after electroforming. The coexistence of CRS and URS is mainly ascribed to the co-effect of electric field and Joule heating mechanisms, indicating that changeable of resistance in this device is dominated by the redistribution of oxygen vacancies in BaTiO3 and the formation, disruption, restoration of conducting filaments in NiO. CRS in bilayer with opposite switching polarities is effective to solve the sneak current without the introduction of any selector elements or an additional metal electrode.

  4. Relaxation of a kinetic hole due to carrier-carrier scattering in multisubband single-quantum-well semiconductors

    DEFF Research Database (Denmark)

    Dery, H.; Tromborg, Bjarne; Eisenstein, G.

    2003-01-01

    We describe a theoretical model for carrier-carrier scattering in an inverted semiconductor quantum well structure using a multisubband diagram. The model includes all possible nonvanishing interaction terms within the static screening approximation, and it enables one to calculate accurately...

  5. Single-layer group IV-V and group V-IV-III-VI semiconductors: Structural stability, electronic structures, optical properties, and photocatalysis

    Science.gov (United States)

    Lin, Jia-He; Zhang, Hong; Cheng, Xin-Lu; Miyamoto, Yoshiyuki

    2017-07-01

    Recently, single-layer group III monochalcogenides have attracted both theoretical and experimental interest at their potential applications in photonic devices, electronic devices, and solar energy conversion. Excited by this, we theoretically design two kinds of highly stable single-layer group IV-V (IV =Si ,Ge , and Sn; V =N and P) and group V-IV-III-VI (IV =Si ,Ge , and Sn; V =N and P; III =Al ,Ga , and In; VI =O and S) compounds with the same structures with single-layer group III monochalcogenides via first-principles simulations. By using accurate hybrid functional and quasiparticle methods, we show the single-layer group IV-V and group V-IV-III-VI are indirect bandgap semiconductors with their bandgaps and band edge positions conforming to the criteria of photocatalysts for water splitting. By applying a biaxial strain on single-layer group IV-V, single-layer group IV nitrides show a potential on mechanical sensors due to their bandgaps showing an almost linear response for strain. Furthermore, our calculations show that both single-layer group IV-V and group V-IV-III-VI have absorption from the visible light region to far-ultraviolet region, especially for single-layer SiN-AlO and SnN-InO, which have strong absorption in the visible light region, resulting in excellent potential for solar energy conversion and visible light photocatalytic water splitting. Our research provides valuable insight for finding more potential functional two-dimensional semiconductors applied in optoelectronics, solar energy conversion, and photocatalytic water splitting.

  6. Terahertz semiconductor nonlinear optics

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias

    2013-01-01

    In this proceedings we describe our recent results on semiconductor nonlinear optics, investigated using single-cycle THz pulses. We demonstrate the nonlinear absorption and self-phase modulation of strong-field THz pulses in doped semiconductors, using n-GaAs as a model system. The THz...... nonlinearity in doped semiconductors originates from the near-instantaneous heating of free electrons in the ponderomotive potential created by electric field of the THz pulse, leading to ultrafast increase of electron effective mass by intervalley scattering. Modification of effective mass in turn leads...... to a decrease of plasma frequency in semiconductor and produces a substantial modification of THz-range material dielectric function, described by the Drude model. As a result, the nonlinearity of both absorption coefficient and refractive index of the semiconductor is observed. In particular we demonstrate...

  7. Organic semiconductor crystals.

    Science.gov (United States)

    Wang, Chengliang; Dong, Huanli; Jiang, Lang; Hu, Wenping

    2018-01-22

    Organic semiconductors have attracted a lot of attention since the discovery of highly doped conductive polymers, due to the potential application in field-effect transistors (OFETs), light-emitting diodes (OLEDs) and photovoltaic cells (OPVs). Single crystals of organic semiconductors are particularly intriguing because they are free of grain boundaries and have long-range periodic order as well as minimal traps and defects. Hence, organic semiconductor crystals provide a powerful tool for revealing the intrinsic properties, examining the structure-property relationships, demonstrating the important factors for high performance devices and uncovering fundamental physics in organic semiconductors. This review provides a comprehensive overview of the molecular packing, morphology and charge transport features of organic semiconductor crystals, the control of crystallization for achieving high quality crystals and the device physics in the three main applications. We hope that this comprehensive summary can give a clear picture of the state-of-art status and guide future work in this area.

  8. Ecological forensics : Using single point stable isotope values to infer seasonal schedules of animals after two diet switches

    NARCIS (Netherlands)

    Jouta, Jeltje; Dietz, Maurine W.; Reneerkens, Jeroen; Piersma, Theunis; Rakhimberdiev, Eldar; Hallgrímsson, Gunnar T.; Pen, Ido

    2017-01-01

    Animals adjust to seasonal challenges in physical, behavioural and spatial ways. Such adjustments are commonly associated with diet changes that often can be characterised isotopically. We introduce the 'double diet switch model', with which the occurrence and timing of two subsequent diet switches

  9. Semiconductor statistics

    CERN Document Server

    Blakemore, J S

    1987-01-01

    In-depth exploration of the implications of carrier populations and Fermi energies examines distribution of electrons in energy bands and impurity levels of semiconductors. Also: kinetics of semiconductors containing excess carriers, particularly in terms of trapping, excitation, and recombination.

  10. Semiconductor physics

    CERN Document Server

    Böer, Karl W

    2018-01-01

    This handbook gives a complete survey of the important topics and results in semiconductor physics. It addresses every fundamental principle and most research topics and areas of application in the field of semiconductor physics. Comprehensive information is provided on crystalline bulk and low-dimensional as well as amporphous semiconductors, including optical, transport, and dynamic properties.

  11. R and D recommendations for future ERDA switch requirements

    International Nuclear Information System (INIS)

    Zucker, O.S.

    1976-01-01

    The following switches are briefly discussed: (1) high pressure and vacuum spark gaps, (2) liquid dielectric gaps, (3) solid dielectrics, (4) nonlinear ferromagnetic materials, (5) semiconductors, superconductors, (6) ferroelectric switches, (7) exploding wires, and (8) plasma instabilities

  12. Terahertz Nonlinear Optics in Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hvam, Jørn Märcher; Hoffmann, Matthias C.

    2013-01-01

    We demonstrate the nonlinear optical effects – selfphase modulation and saturable absorption of a single-cycle THz pulse in a semiconductor. Resulting from THz-induced modulation of Drude plasma, these nonlinear optical effects, in particular, lead to self-shortening and nonlinear spectral...... breathing of a single-cycle THz pulse in a semiconductor....

  13. TERRA and hnRNPA1 orchestrate an RPA-to-POT1 switch on telomeric single-stranded DNA.

    Science.gov (United States)

    Flynn, Rachel Litman; Centore, Richard C; O'Sullivan, Roderick J; Rai, Rekha; Tse, Alice; Songyang, Zhou; Chang, Sandy; Karlseder, Jan; Zou, Lee

    2011-03-24

    Maintenance of telomeres requires both DNA replication and telomere 'capping' by shelterin. These two processes use two single-stranded DNA (ssDNA)-binding proteins, replication protein A (RPA) and protection of telomeres 1 (POT1). Although RPA and POT1 each have a critical role at telomeres, how they function in concert is not clear. POT1 ablation leads to activation of the ataxia telangiectasia and Rad3-related (ATR) checkpoint kinase at telomeres, suggesting that POT1 antagonizes RPA binding to telomeric ssDNA. Unexpectedly, we found that purified POT1 and its functional partner TPP1 are unable to prevent RPA binding to telomeric ssDNA efficiently. In cell extracts, we identified a novel activity that specifically displaces RPA, but not POT1, from telomeric ssDNA. Using purified protein, here we show that the heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1) recapitulates the RPA displacing activity. The RPA displacing activity is inhibited by the telomeric repeat-containing RNA (TERRA) in early S phase, but is then unleashed in late S phase when TERRA levels decline at telomeres. Interestingly, TERRA also promotes POT1 binding to telomeric ssDNA by removing hnRNPA1, suggesting that the re-accumulation of TERRA after S phase helps to complete the RPA-to-POT1 switch on telomeric ssDNA. Together, our data suggest that hnRNPA1, TERRA and POT1 act in concert to displace RPA from telomeric ssDNA after DNA replication, and promote telomere capping to preserve genomic integrity.

  14. Polarization-switching dynamics and microstructures of ferroelectric (Bi0.5Na0.5)TiO3 single crystals

    Science.gov (United States)

    Yanai, Ken; Onozuka, Hiroaki; Kitanaka, Yuuki; Noguchi, Yuji; Miyayama, Masaru; Moriyoshi, Chikako; Kuroiwa, Yoshihiro; Kurushima, Kousuke; Mori, Shigeo

    2013-04-01

    Single crystals of ferroelectric (Bi0.5Na0.5)TiO3 were successfully grown by using the top-seeded solution growth method at a high oxygen pressure of 0.9 MPa and their polarization switching dynamics along the c direction and their domain structures were investigated. Piezoelectric force microscope (PFM) observations show that BNT crystals poled along the c direction. had 71-degree domains in which the spontaneous polarization ( P s ) vector was opposite to the direction of the poling electric field. Synchrotron-radiation single-crystal X-ray diffraction analyses and PFM observations revealed that the polarization switching in the BNT crystals along the c direction was achieved by a 71-degree rotation of the P s vector.

  15. Single-particle spectroscopy of I-III-VI semiconductor nanocrystals: spectral diffusion and suppression of blinking by two-color excitation.

    Science.gov (United States)

    Sharma, Dharmendar Kumar; Hirata, Shuzo; Bujak, Lukasz; Biju, Vasudevanpillai; Kameyama, Tatsuya; Kishi, Marino; Torimoto, Tsukasa; Vacha, Martin

    2016-07-14

    Ternary I-III-VI semiconductor nanocrystals have been explored as non-toxic alternatives to II-VI semiconductors for optoelectronic and sensing applications, but large photoluminescence spectral width and moderate brightness restrict their practical use. Here, using single-particle photoluminescence spectroscopy on nanocrystals of (AgIn)xZn2(1-x)S2 we show that the photoluminescence band is inhomogeneously broadened and that size distribution is the dominant factor in the broadening. The residual homogeneous linewidth of individual nanocrystals reaches up to 75% of the ensemble spectral width. Single nanocrystals undergo spectral diffusion which also contributes to the inhomogeneous band. Excitation with two lasers with energies above and below the bandgap reveals coexistence of two emitting donor states within one particle. Spectral diffusion in such particles is due to temporal activation and deactivation of one such state. Filling of a trap state with a lower-energy laser enables optical modulation of photoluminescence intermittency (blinking) and leads to an almost two-fold increase in brightness.

  16. Stable CW Single Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

    Science.gov (United States)

    Duerksen, Gary L.; Krainak, Michael A.

    1999-01-01

    Previously, single-frequency semiconductor laser operation using fiber Bragg gratings has been achieved by tWo methods: 1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element'; 2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback'. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback.

  17. A Switch Is Not a Switch: Syntactically-Driven Bilingual Language Control

    Science.gov (United States)

    Gollan, Tamar H.; Goldrick, Matthew

    2018-01-01

    The current study investigated the possibility that language switches could be relatively automatically triggered by context. "Single-word switches," in which bilinguals switched languages on a single word in midsentence and then immediately switched back, were contrasted with more complete "whole-language switches," in which…

  18. Compact semiconductor lasers

    CERN Document Server

    Yu, Siyuan; Lourtioz, Jean-Michel

    2014-01-01

    This book brings together in a single volume a unique contribution by the top experts around the world in the field of compact semiconductor lasers to provide a comprehensive description and analysis of the current status as well as future directions in the field of micro- and nano-scale semiconductor lasers. It is organized according to the various forms of micro- or nano-laser cavity configurations with each chapter discussing key technical issues, including semiconductor carrier recombination processes and optical gain dynamics, photonic confinement behavior and output coupling mechanisms, carrier transport considerations relevant to the injection process, and emission mode control. Required reading for those working in and researching the area of semiconductors lasers and micro-electronics.

  19. Effect of different substitution position on the switching behavior in single-molecule device with carbon nanotube electrodes

    Science.gov (United States)

    Yang, Jingjuan; Han, Xiaoxiao; Yuan, Peipei; Bian, Baoan; Wang, Yixiang

    2018-01-01

    We investigate the electronic transport properties of dihydroazulene (DHA) and vinylheptafulvene (VHF) molecule sandwiched between two carbon nanotubes using density functional theory and non-equilibrium Green's function. The device displays significantly switching behavior between DHA and VHF isomerizations. It is found the different substitution position of F in the molecule influences the switching ratio of device, which is analyzed by transmission spectra and molecular projected self-consistent Hamiltonian. The observed negative differential resistance effect is explained by transmission spectra and transmission eigenstates of transmission peak in the bias window. The observed reverse of current in VHF form in which two H atoms on the right side of the benzene ring of the molecule are replaced by F is explained by transmission spectra and molecule-electrode coupling with the varied bias. The results suggest that the reasonable substitution position of molecule may improve the switching ratio, displaying a potential application in future molecular circuit.

  20. An investigation of the mass spectra of secondary ions ejected from the single crystal surface of semiconductors

    International Nuclear Information System (INIS)

    Koval', A.G.; Mel'nikov, V.N.; Enukov, Yu.V.

    1976-01-01

    The mass spectra of secondary positive and negative ions, ejected by an Ar + ion beam from the (100) face of an epitaxial film of the semiconductor Alsub(x)Gasub(1-x)As were investigated. There are many various secondary ions in the mass spectrum under investigation. They may be divided into four groups according to their origins. Mass spectra of secondary positive and negative secondary ions differ much, either in their composition or the intensities of homogeneous ions. The I(T) dependences (I=the current of corresponding secondary ions, T=target temperature) were obtained for secondary and negative ions taken from groups differing by their origin. The I(T) dependences were obtained at several oxygen pressures in a chamber. For the ions with 'superficial' origin a strong dependence of their current on target temperature is observed. Oxygen pressure increase leads to substantial change of the I(T)curves. (Auth.)

  1. A Single-Stage LED Tube Lamp Driver with Power-Factor Corrections and Soft Switching for Energy-Saving Indoor Lighting Applications

    Directory of Open Access Journals (Sweden)

    Chun-An Cheng

    2017-01-01

    Full Text Available This paper presents a single-stage alternating current (AC/direct current (DC light-emitting diode (LED tube lamp driver for energy-saving indoor lighting applications; this driver features power-factor corrections and soft switching, and also integrates a dual buck-boost converter with coupled inductors and a half-bridge series resonant converter cascaded with a bridge rectifier into a single-stage power-conversion topology. The features of the presented driver are high efficiency (>91%, satisfying power factor (PF > 0.96, low input-current total-harmonic distortion (THD < 10%, low output voltage ripple factor (<7.5%, low output current ripple factor (<8%, and zero-voltage switching (ZVS obtained on both power switches. Operational principles are described in detail, and experimental results obtained from an 18 W-rated LED tube lamp for T8/T10 fluorescent lamp replacements with input utility-line voltages ranging from 100 V to 120 V have demonstrated the functionality of the presented driver suitable for indoor lighting applications.

  2. All-optical switching of localized surface plasmon resonance in single gold nanosandwich using GeSbTe film as an active medium

    Energy Technology Data Exchange (ETDEWEB)

    Hira, T.; Homma, T.; Uchiyama, T.; Kuwamura, K.; Kihara, Y.; Saiki, T. [Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku, Yokohama, Kanagawa 223-8522 (Japan)

    2015-01-19

    Localized surface plasmon resonance (LSPR) switching was investigated in a Au/GeSbTe/Au nanosandwich as a key active element for plasmonic integrated circuits and devices. Near-infrared single-particle spectroscopy was conducted to examine the interaction of a Au nanorod (AuNR) and Au film, between which a GeSbTe layer was incorporated as an active phase-change media. Numerical calculation revealed that hybridized modes of the AuNR and Au film exhibit a significant change of scattering intensity with the phase change. In particular, the antisymmetric (magnetic resonance) mode can be modulated effectively by the extinction coefficient of GST, as well as its refractive index. Experimental demonstration of the switching operation was performed by alternate irradiation with a picosecond pulsed laser for amorphization and a continuous wave laser for crystallization. Repeatable modulation was obtained by monitoring the scattering light around the LSPR peak at λ = 1070 nm.

  3. Note: A disposable x-ray camera based on mass produced complementary metal-oxide-semiconductor sensors and single-board computers

    Energy Technology Data Exchange (ETDEWEB)

    Hoidn, Oliver R.; Seidler, Gerald T., E-mail: seidler@uw.edu [Physics Department, University of Washington, Seattle, Washington 98195 (United States)

    2015-08-15

    We have integrated mass-produced commercial complementary metal-oxide-semiconductor (CMOS) image sensors and off-the-shelf single-board computers into an x-ray camera platform optimized for acquisition of x-ray spectra and radiographs at energies of 2–6 keV. The CMOS sensor and single-board computer are complemented by custom mounting and interface hardware that can be easily acquired from rapid prototyping services. For single-pixel detection events, i.e., events where the deposited energy from one photon is substantially localized in a single pixel, we establish ∼20% quantum efficiency at 2.6 keV with ∼190 eV resolution and a 100 kHz maximum detection rate. The detector platform’s useful intrinsic energy resolution, 5-μm pixel size, ease of use, and obvious potential for parallelization make it a promising candidate for many applications at synchrotron facilities, in laser-heating plasma physics studies, and in laboratory-based x-ray spectrometry.

  4. Ecological forensics: using single point stable isotope values to infer seasonal schedules of animals after two diet switches

    NARCIS (Netherlands)

    Jouta, J.; Dietz, M.W.; Reneerkens, J.; Piersma, T.; Rakhimberdiev, E.; Hallgrimsson, G.T.; Pen, I.

    2017-01-01

    1.Animals adjust to seasonal challenges in physical, behavioural and spatial ways. Such adjustments are commonly associated with diet changes that often can be characterised isotopically.2.We introduce the ‘double diet switch model’, with which the occurrence and timing of two subsequent diet

  5. Optimization of multi-branch switched diversity systems

    KAUST Repository

    Nam, Haewoon; Alouini, Mohamed-Slim

    2009-01-01

    A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold

  6. Coexistence and switching of anticipating synchronization and lag synchronization in an optical system

    International Nuclear Information System (INIS)

    Wu, Liang; Zhu, Shiqun

    2003-01-01

    The chaotic synchronization between two bi-directionally coupled external cavity single-mode semiconductor lasers is investigated. Numerical simulation shows that anticipating synchronization and lag synchronization coexist and switch between each other in certain parameter regime. The anticipating time with different effects that were discussed quite differently in the previous theoretical analysis and experimental observation is determined by the involved parameters in the system

  7. Single-electron regime and Pauli spin blockade in a silicon metal-oxide-semiconductor double quantum dot

    Science.gov (United States)

    Rochette, Sophie; Ten Eyck, Gregory A.; Pluym, Tammy; Lilly, Michael P.; Carroll, Malcolm S.; Pioro-Ladrière, Michel

    2015-03-01

    Silicon quantum dots are promising candidates for quantum information processing as spin qubits with long coherence time. We present electrical transport measurements on a silicon metal-oxide-semiconductor (MOS) double quantum dot (DQD). First, Coulomb diamonds measurements demonstrate the one-electron regime at a relatively high temperature of 1.5 K. Then, the 8 mK stability diagram shows Pauli spin blockade with a large singlet-triplet separation of approximatively 0.40 meV, pointing towards a strong lifting of the valley degeneracy. Finally, numerical simulations indicate that by integrating a micro-magnet to those devices, we could achieve fast spin rotations of the order of 30 ns. Those results are part of the recent body of work demonstrating the potential of Si MOS DQD as reliable and long-lived spin qubits that could be ultimately integrated into modern electronic facilities. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. DOE's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  8. Broadband photonic single sideband frequency up-converter based on the cross polarization modulation effect in a semiconductor optical amplifier for radio-over-fiber systems.

    Science.gov (United States)

    Lee, Seung-Hun; Kim, Hyoung-Jun; Song, Jong-In

    2014-01-13

    A broadband photonic single sideband (SSB) frequency up-converter based on the cross polarization modulation (XPolM) effect in a semiconductor optical amplifier (SOA) is proposed and experimentally demonstrated. An optical radio frequency (RF) signal in the form of an optical single sideband (OSSB) is generated by the photonic SSB frequency up-converter to solve the power fading problem caused by fiber chromatic dispersion. The generated OSSB RF signal has almost identical optical carrier power and optical sideband power. This SSB frequency up-conversion scheme shows an almost flat electrical RF power response as a function of the RF frequency in a range from 31 GHz to 75 GHz after 40 km single mode fiber (SMF) transmission. The photonic SSB frequency up-conversion technique shows negligible phase noise degradation. The phase noise of the up-converted RF signal at 49 GHz for an offset of 10 kHz is -93.17 dBc/Hz. Linearity analysis shows that the photonic SSB frequency up-converter has a spurious free dynamic range (SFDR) value of 79.51 dB · Hz(2/3).

  9. Metal-coated semiconductor nanostructures and simulation of photon extraction and coupling to optical fibers for a solid-state single-photon source

    International Nuclear Information System (INIS)

    Suemune, Ikuo; Nakajima, Hideaki; Liu, Xiangming; Odashima, Satoru; Asano, Tomoya; Iijima, Hitoshi; Huh, Jae-Hoon; Idutsu, Yasuhiro; Sasakura, Hirotaka; Kumano, Hidekazu

    2013-01-01

    We have realized metal-coated semiconductor nanostructures for a stable and efficient single-photon source (SPS) and demonstrated improved single-photon extraction efficiency by the selection of metals and nanostructures. We demonstrate with finite-difference time-domain (FDTD) simulations that inclination of a pillar sidewall, which changes the structure to a nanocone, is effective in improving the photon extraction efficiency. We demonstrate how such nanocone structures with inclined sidewalls are fabricated with reactive ion etching. With the optimized design, a photon extraction efficiency to outer airside as high as ∼97% generated from a quantum dot in a nanocone structure is simulated, which is the important step in realizing SPS on-demand operations. We have also examined the direct contact of such a metal-embedded nanocone structure with a single-mode fiber facet as a simple and practical method for preparing fiber-coupled SPS and demonstrated practical coupling efficiencies of ∼16% with FDTD simulation. (paper)

  10. Complete resolution of minocycline pigmentation following a single treatment with non-ablative 1550-nm fractional resurfacing in combination with the 755-nm Q-switched alexandrite laser.

    Science.gov (United States)

    Vangipuram, Ramya K; DeLozier, Whitney L; Geddes, Elizabeth; Friedman, Paul M

    2016-03-01

    Pigmentation secondary to minocycline ingestion is an uncommon adverse event affecting 3.7-14.8% of treated individuals for which few effective therapies are available. Three patterns of minocycline pigmentation have a characteristic clinical and histological appearance. The pigment composition in each variety is different and occurs at varying skin depths. Accordingly, a tailored approach according to the type of minocycline pigmentation is crucial for treatment success. The purpose of this intervention was to evaluate the efficacy of non-ablative fractional photothermolysis in combination with the Q-switched alexandrite laser for the treatment of type I minocycline pigmentation on the face. A patient with type I minocycline pigmentation was treated with non-ablative 1550-nm fractional photothermolysis followed immediately by 755-nm Q-switched alexandrite laser and then observed clinically to determine the outcome of this modality. The patient was seen in clinic 1 month later following her single treatment session and 100% clearance of all blue facial pigment was observed. Non-ablative fractional photothermolysis in combination with the 755-nm Q-switched alexandrite laser should be considered for treatment of type I minocycline pigmentation. © 2015 Wiley Periodicals, Inc.

  11. Semiconductor Manufacturing equipment introduction

    International Nuclear Information System (INIS)

    Im, Jong Sun

    2001-02-01

    This book deals with semiconductor manufacturing equipment. It is comprised of nine chapters, which are manufacturing process of semiconductor device, history of semiconductor manufacturing equipment, kinds and role of semiconductor manufacturing equipment, construction and method of semiconductor manufacturing equipment, introduction of various semiconductor manufacturing equipment, spots of semiconductor manufacturing, technical elements of semiconductor manufacturing equipment, road map of technology of semiconductor manufacturing equipment and semiconductor manufacturing equipment in the 21st century.

  12. A Novel Offset Cancellation Based on Parasitic-Insensitive Switched-Capacitor Sensing Circuit for the Out-of-Plane Single-Gimbaled Decoupled CMOS-MEMS Gyroscope

    Science.gov (United States)

    Chang, Ming-Hui; Huang, Han-Pang

    2013-01-01

    This paper presents a novel parasitic-insensitive switched-capacitor (PISC) sensing circuit design in order to obtain high sensitivity and ultra linearity and reduce the parasitic effect for the out-of-plane single-gimbaled decoupled CMOS-MEMS gyroscope (SGDG). According to the simulation results, the proposed PISC circuit has better sensitivity and high linearity in a wide dynamic range. Experimental results also show a better performance. In addition, the PISC circuit can use signal processing to cancel the offset and noise. Thus, this circuit is very suitable for gyroscope measurement. PMID:23493122

  13. Semiconductor spintronics

    CERN Document Server

    Xia, Jianbai; Chang, Kai

    2012-01-01

    Semiconductor Spintronics, as an emerging research discipline and an important advanced field in physics, has developed quickly and obtained fruitful results in recent decades. This volume is the first monograph summarizing the physical foundation and the experimental results obtained in this field. With the culmination of the authors' extensive working experiences, this book presents the developing history of semiconductor spintronics, its basic concepts and theories, experimental results, and the prospected future development. This unique book intends to provide a systematic and modern foundation for semiconductor spintronics aimed at researchers, professors, post-doctorates, and graduate students, and to help them master the overall knowledge of spintronics.

  14. Saturated evanescent-wave absorption of few-layer graphene-covered side-polished single-mode fiber for all-optical switching

    Science.gov (United States)

    Peng, Kaung-Jay; Wu, Chun-Lung; Lin, Yung-Hsiang; Wang, Hwai-Yung; Cheng, Chih-Hsien; Chi, Yu-Chieh; Lin, Gong-Ru

    2018-01-01

    Using the evanescent-wave saturation effect of hydrogen-free low-temperature synthesized few-layer graphene covered on the cladding region of a side-polished single-mode fiber, a blue pump/infrared probe-based all-optical switch is demonstrated with specific wavelength-dependent probe modulation efficiency. Under the illumination of a blue laser diode at 405 nm, the few-layer graphene exhibits cross-gain modulation at different wavelengths covering the C- and L-bands. At a probe power of 0.5 mW, the L-band switching throughput power variant of 16 μW results in a probe modulation depth of 3.2%. Blue shifting the probe wavelength from 1580 to 1520 nm further enlarges the switching throughput power variant to 24 mW and enhances the probe modulation depth to 5%. Enlarging the probe power from 0.5 to 1 mW further enlarges the switching throughput power variant from 25 to 58 μW to promote its probe modulation depth of up to 5.8% at 1520 nm. In contrast, the probe modulation depth degrades from 5.1% to 1.2% as the pumping power reduces from 85 to 24 mW, which is attributed to the saturable absorption of the few-layer graphene-based evanescent-wave absorber. The modulation depth at wavelength of 1550 nm under a probe power of 1 mW increases from 1.2% to 5.1%, as more carriers can be excited when increasing the blue laser power from 24 to 85 mW, whereas it decreases from 5.1% to 3.3% by increasing the input probe power from 1 to 2 mW to show an easier saturated condition at longer wavelength.

  15. Many-particle theory of optical properties in low-dimensional nanostructures. Dynamics in single-walled carbon nanotubes and semiconductor quantum dots

    International Nuclear Information System (INIS)

    Malic, Ermin

    2008-01-01

    This work focuses on the theoretical investigation of optical properties of low-dimensional nanostructures, specifically single-walled carbon nanotubes (CNTs) and self-assembled InAs/GaAs quantum dots (QDs). The density-matrix formalism is applied to explain recent experimental results and to give insight into the underlying physics. A microscopic calculation of the absorption coefficient and the Rayleigh scattering cross section is performed by a novel approach combining the density-matrix formalism with the tight-binding wave functions. The calculated spectra of metallic nanotubes show a double-peaked structure resulting from the trigonal warping effect. The intensity ratios of the four lowest-lying transitions in both absorption and Rayleigh spectra can be explained by the different behavior of the optical matrix elements along the high-symmetry lines K-Γ and K-M. The Rayleigh line shape is predicted to be asymmetric, with an enhanced cross section for lower photon energies arising from non-resonant contributions of the optical susceptibility. Furthermore, the Coulomb interaction is shown to be maximal when the momentum transfer is low. For intersubband processes with a perpendicular momentum transfer, the coupling strength is reduced to less than 5%. The chirality and diameter dependence of the excitonic binding energy and the transition frequency are presented in Kataura plots. Furthermore, the influence of the surrounding environment on the optical properties of CNTs is investigated. Extending the confinement to all three spatial dimensions, semiconductor Bloch equation are derived to describe the dynamics in QD semiconductor lasers and amplifiers. A detailed microscopic analysis of the nonlinear turn-on dynamics of electrically pumped InAs/GaAs QD lasers is performed, showing the generation of relaxation oscillations on a nanosecond time scale in both the photon and charge carrier density. The theory predicts a strong damping of relaxation oscillations

  16. The Effects of Different Electron-Phonon Couplings on the Spectral and Transport Properties of Small Molecule Single-Crystal Organic Semiconductors

    Directory of Open Access Journals (Sweden)

    Carmine Antonio Perroni

    2014-03-01

    Full Text Available Spectral and transport properties of small molecule single-crystal organic semiconductors have been theoretically analyzed focusing on oligoacenes, in particular on the series from naphthalene to rubrene and pentacene, aiming to show that the inclusion of different electron-phonon couplings is of paramount importance to interpret accurately the properties of prototype organic semiconductors. While in the case of rubrene, the coupling between charge carriers and low frequency inter-molecular modes is sufficient for a satisfactory description of spectral and transport properties, the inclusion of electron coupling to both low-frequency inter-molecular and high-frequency intra-molecular vibrational modes is needed to account for the temperature dependence of transport properties in smaller oligoacenes. For rubrene, a very accurate analysis in the relevant experimental configuration has allowed for the clarification of the origin of the temperature-dependent mobility observed in these organic semiconductors. With increasing temperature, the chemical potential moves into the tail of the density of states corresponding to localized states, but this is not enough to drive the system into an insulating state. The mobility along different crystallographic directions has been calculated, including vertex corrections that give rise to a transport lifetime one order of magnitude smaller than the spectral lifetime of the states involved in the transport mechanism. The mobility always exhibits a power-law behavior as a function of temperature, in agreement with experiments in rubrene. In systems gated with polarizable dielectrics, the electron coupling to interface vibrational modes of the gate has to be included in addition to the intrinsic electron-phonon interaction. While the intrinsic bulk electron-phonon interaction affects the behavior of mobility in the coherent regime below room temperature, the coupling with interface modes is dominant for the

  17. Many-particle theory of optical properties in low-dimensional nanostructures. Dynamics in single-walled carbon nanotubes and semiconductor quantum dots

    Energy Technology Data Exchange (ETDEWEB)

    Malic, Ermin

    2008-09-02

    This work focuses on the theoretical investigation of optical properties of low-dimensional nanostructures, specifically single-walled carbon nanotubes (CNTs) and self-assembled InAs/GaAs quantum dots (QDs). The density-matrix formalism is applied to explain recent experimental results and to give insight into the underlying physics. A microscopic calculation of the absorption coefficient and the Rayleigh scattering cross section is performed by a novel approach combining the density-matrix formalism with the tight-binding wave functions. The calculated spectra of metallic nanotubes show a double-peaked structure resulting from the trigonal warping effect. The intensity ratios of the four lowest-lying transitions in both absorption and Rayleigh spectra can be explained by the different behavior of the optical matrix elements along the high-symmetry lines K-{gamma} and K-M. The Rayleigh line shape is predicted to be asymmetric, with an enhanced cross section for lower photon energies arising from non-resonant contributions of the optical susceptibility. Furthermore, the Coulomb interaction is shown to be maximal when the momentum transfer is low. For intersubband processes with a perpendicular momentum transfer, the coupling strength is reduced to less than 5%. The chirality and diameter dependence of the excitonic binding energy and the transition frequency are presented in Kataura plots. Furthermore, the influence of the surrounding environment on the optical properties of CNTs is investigated. Extending the confinement to all three spatial dimensions, semiconductor Bloch equation are derived to describe the dynamics in QD semiconductor lasers and amplifiers. A detailed microscopic analysis of the nonlinear turn-on dynamics of electrically pumped InAs/GaAs QD lasers is performed, showing the generation of relaxation oscillations on a nanosecond time scale in both the photon and charge carrier density. The theory predicts a strong damping of relaxation oscillations

  18. High-power actively Q-switched single-mode 1342 nm Nd:YVO4 ring laser, injection-locked by a cw single-frequency microchip laser.

    Science.gov (United States)

    Koch, Peter; Bartschke, Juergen; L'huillier, Johannes A

    2015-11-30

    In this paper we report on the realization of a single-mode Q-switched Nd:YVO4 ring laser at 1342 nm. Unidirectional and single-mode operation of the ring laser is achieved by injection-locking with a continuous wave Nd:YVO4 microchip laser, emitting a single-frequency power of up to 40 mW. The ring laser provides a single-mode power of 13.9 W at 10 kHz pulse repetition frequency with a pulse duration of 18.2 ns and an excellent beam quality (M2 laser, a power of 8.7 W at 671 nm with a pulse duration of 14.8 ns and a beam propagation factor of M2 < 1.1 is obtained. The 671 nm radiation features a long-term spectral width of 75 MHz.

  19. Ternary chalcopyrite semiconductors

    CERN Document Server

    Shay, J L; Pamplin, B R

    2013-01-01

    Ternary Chalcopyrite Semiconductors: Growth, Electronic Properties, and Applications covers the developments of work in the I-III-VI2 and II-IV-V2 ternary chalcopyrite compounds. This book is composed of eight chapters that focus on the crystal growth, characterization, and applications of these compounds to optical communications systems. After briefly dealing with the status of ternary chalcopyrite compounds, this book goes on describing the crystal growth of II-IV-V2 and I-III-VI2 single crystals. Chapters 3 and 4 examine the energy band structure of these semiconductor compounds, illustrat

  20. Energy-switching potential energy surface for the water molecule revisited: A highly accurate singled-sheeted form.

    Science.gov (United States)

    Galvão, B R L; Rodrigues, S P J; Varandas, A J C

    2008-07-28

    A global ab initio potential energy surface is proposed for the water molecule by energy-switching/merging a highly accurate isotope-dependent local potential function reported by Polyansky et al. [Science 299, 539 (2003)] with a global form of the many-body expansion type suitably adapted to account explicitly for the dynamical correlation and parametrized from extensive accurate multireference configuration interaction energies extrapolated to the complete basis set limit. The new function mimics also the complicated Sigma/Pi crossing that arises at linear geometries of the water molecule.

  1. A comparison between the response of compound semiconductor detectors in single and back-to-back configuration

    International Nuclear Information System (INIS)

    Auricchio, N.; Donati, A.; Dusi, W.; Perillo, E.; Siffert, P.

    2004-01-01

    CdTe detectors (3 x 5 mm 2 electrode area and 1 mm thick), mounted in a back-to-back configuration with common anode, have been characterized, aiming at determining the actual regions of these devices giving the best and almost constant spectroscopic performance. This configuration ensures that the maximum paths of the charge carriers correspond to the inter-electrode distances and consequently the spectroscopic performance is essentially the same as for the single coupled detectors, but allows one: - to double the useful absorbing thickness when irradiated in the classical planar parallel field geometry; - to double the pixel area when irradiated in the planar transverse field (PTF) geometry, while the absorbing thickness can be freely adjusted according to the experimental requirements. The tests were performed in PTF geometry by using well collimated photon beams (10-300 keV energy range) obtained by a 20 mm thick tungsten collimator having a 0.1 x 1 or a 0.3 x 1 mm 2 collimating channel. Experimental results concerning the spectroscopic behaviour of the coupled detectors have been compared with those obtained by single devices having the same thickness as the single components or the same total thickness as the coupled device. The results show that the back-to-back configuration does not introduce further significant noise with respect to 1 mm thick single detectors and their spectroscopic performance is similar or better than the one shown by 2 mm thick single devices for fine and wide collimator measurements, and mostly in the uncollimated case

  2. Design and Implementation of a High Efficiency, Low Component Voltage Stress, Single-Switch High Step-Up Voltage Converter for Vehicular Green Energy Systems

    Directory of Open Access Journals (Sweden)

    Yu-En Wu

    2016-09-01

    Full Text Available In this study, a novel, non-isolated, cascade-type, single-switch, high step-up DC/DC converter was developed for green energy systems. An integrated coupled inductor and voltage lift circuit were applied to simplify the converter structure and satisfy the requirements of high efficiency and high voltage gain ratios. In addition, the proposed structure is controllable with a single switch, which effectively reduces the circuit cost and simplifies the control circuit. With the leakage inductor energy recovery function and active voltage clamp characteristics being present, the circuit yields optimizable conversion efficiency and low component voltage stress. After the operating principles of the proposed structure and characteristics of a steady-state circuit were analyzed, a converter prototype with 450 W, 40 V of input voltage, 400 V of output voltage, and 95% operating efficiency was fabricated. The Renesas MCU RX62T was employed to control the circuits. Experimental results were analyzed to validate the feasibility and effectiveness of the proposed system.

  3. Crosstalk error correction through dynamical decoupling of single-qubit gates in capacitively coupled singlet-triplet semiconductor spin qubits

    Science.gov (United States)

    Buterakos, Donovan; Throckmorton, Robert E.; Das Sarma, S.

    2018-01-01

    In addition to magnetic field and electric charge noise adversely affecting spin-qubit operations, performing single-qubit gates on one of multiple coupled singlet-triplet qubits presents a new challenge: crosstalk, which is inevitable (and must be minimized) in any multiqubit quantum computing architecture. We develop a set of dynamically corrected pulse sequences that are designed to cancel the effects of both types of noise (i.e., field and charge) as well as crosstalk to leading order, and provide parameters for these corrected sequences for all 24 of the single-qubit Clifford gates. We then provide an estimate of the error as a function of the noise and capacitive coupling to compare the fidelity of our corrected gates to their uncorrected versions. Dynamical error correction protocols presented in this work are important for the next generation of singlet-triplet qubit devices where coupling among many qubits will become relevant.

  4. Single Event Upset Rate Estimates for a 16-K CMOS (Complementary Metal Oxide Semiconductor) SRAM (Static Random Access Memory).

    Science.gov (United States)

    1986-09-30

    4 . ~**..ft.. ft . - - - ft SI TABLES 9 I. SA32~40 Single Event Upset Test, 1140-MeV Krypton, 9/l8/8~4. . .. .. .. .. .. .16 II. CRUP Simulation...cosmic ray interaction analysis described in the remainder of this report were calculated using the CRUP computer code 3 modified for funneling. The... CRUP code requires, as inputs, the size of a depletion region specified as a retangular parallel piped with dimensions a 9 b S c, the effective funnel

  5. Sandwich-like singled-walled titania nanotube as a novel semiconductor electrode for quantum dot-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Cunku; Li, Xin; Fan, Xiujuan [Department of Chemistry, Harbin Institute of Technology, Harbin 150090 (China); Qi, Jingyao [School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090 (China)

    2012-06-15

    A novel sandwich-like singled-walled titania nanotube is designed as a photoanode in quantum dot-sensitized solar cells. It acts as a hollow coaxial nanocable, in which the injected electron is confined in the conducting layer for transport, guarded from electron recombination by the protective layers. An ultrafast interfacial electron transfer is also expected in this photoelectric system due to the unique nanoarchitecture. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  6. Semiconductor spintronics

    International Nuclear Information System (INIS)

    Fabian, J.; Abiague, A.M.; Ertler, Ch.; Stano, P.; Zutic, I.

    2007-01-01

    Spintronics refers commonly to phenomena in which the spin of electrons in a solid state environment plays the determining role. In a more narrow sense spintronics is an emerging research field of electronics: spintronics devices are based on a spin control of electronics, or on an electrical and optical control of spin of magnetism. While metal spintronics has already found its niche in the computer industry - giant magnetoresistance systems are used as hard disk read heads - semiconductor spintronics is vet demonstrate its full potential. This review presents selected themes of semiconductor spintronics, introducing important concepts in spin transport, spin transport, spin injection. Silsbee-Johnson spin-charge coupling, and spin-dependent tunneling, as well as spin relaxation and spin dynamics. The most fundamental spin-dependent interaction in nonmagnetic semiconductors is spin-orbit coupling. Depending on the crystal symmetries of the material, as well as on the structural properties of semiconductor based heterostructures, the spin-orbit coupling takes on different functional forms, giving a nice playground of effective spin-orbit Hamiltonians. The effective Hamiltonians for the most relevant classes of materials and heterostructures are derived here from realistic electronic band structure descriptions. Most semiconductor device systems are still theoretical concepts, waiting for experimental demonstrations. A review of selected proposed, and a few demonstrated devices is presented, with detailed description of two important classes: magnetic resonant tunnel structures and bipolar magnetic diodes and transistors. In view of the importance of ferromagnetic semiconductor material, a brief discussion of diluted magnetic semiconductors is included. In most cases the presentation is of tutorial style, introducing the essential theoretical formalism at an accessible level, with case-study-like illustrations of actual experimental results, as well as with brief

  7. Statistical properties of intensity of partially polarised semiconductor laser light backscattered by a single-mode optical fibre

    International Nuclear Information System (INIS)

    Alekseev, A E; Potapov, V T; Gorshkov, B G

    2015-01-01

    We report the results of studying statistical properties of the intensity of partially polarised coherent light backscattered by a single mode optical fibre. An expression is derived for the deviation of the backscattered light intensity depending on the scattering region length, the degree of the light source coherence and the degree of scattered light polarisation. It is shown that the backscattered light in a fibre scattered-light interferometer is partially polarised with the polarisation degree P = 1/3 in the case of external perturbations of the interferometer fibre. (scattering of light)

  8. Nitride semiconductor devices fundamentals and applications

    CERN Document Server

    Morkoç, Hadis

    2013-01-01

    This book gives a clear presentation of the necessary basics of semiconductor and device physics and engineering. It introduces readers to fundamental issues that will enable them to follow the latest technological research. It also covers important applications, including LED and lighting, semiconductor lasers, high power switching devices, and detectors. This balanced and up-to-date treatment makes the text an essential educational tool for both advanced students and professionals in the electronics industry.

  9. Gain and Index Dynamics in Semiconductor Lasers

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher

    Semiconductor optical amplifiers (SOAs) provide ultrafast, i.e. broadband components for optical communication systems. They enter not only as signal generators and amplifiers, but also as nonlinear elements for ultrafast signal processing such as wavelength conversion, switching, and regeneration...... changed character from bulk semiconductor to quantum wells and most recently to quantum dots. By quantum confinement of the carriers, the light-matter interactions can be significantly modified and the optical properties, including dynamics, can be engineered to match the required functionalities...

  10. Capacitance characteristics of metal-oxide-semiconductor capacitors with a single layer of embedded nickel nanoparticles for the application of nonvolatile memory

    International Nuclear Information System (INIS)

    Wei, Li; Ling, Xu; Wei-Ming, Zhao; Hong-Lin, Ding; Zhong-Yuan, Ma; Jun, Xu; Kun-Ji, Chen

    2010-01-01

    This paper reports that metal-oxide-semiconductor (MOS) capacitors with a single layer of Ni nanoparticles were successfully fabricated by using electron-beam evaporation and rapid thermal annealing for application to nonvolatile memory. Experimental scanning electron microscopy images showed that Ni nanoparticles of about 5 nm in diameter were clearly embedded in the SiO 2 layer on p-type Si (100). Capacitance–voltage measurements of the MOS capacitor show large flat-band voltage shifts of 1.8 V, which indicate the presence of charge storage in the nickel nanoparticles. In addition, the charge-retention characteristics of MOS capacitors with Ni nanoparticles were investigated by using capacitance–time measurements. The results showed that there was a decay of the capacitance embedded with Ni nanoparticles for an electron charge after 10 4 s. But only a slight decay of the capacitance originating from hole charging was observed. The present results indicate that this technique is promising for the efficient formation or insertion of metal nanoparticles inside MOS structures. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  11. Bi-photon imaging and diagnostics using ultra-small diagnostic probes engineered from semiconductor nanocrystals and single-domain antibodies

    Science.gov (United States)

    Hafian, Hilal; Sukhanova, Alyona; Chames, Patrick; Baty, Daniel; Pluot, Michel; Cohen, Jacques H. M.; Nabiev, Igor R.; Millot, Jean-Marc

    2012-10-01

    Semiconductor fluorescent quantum dots (QDs) have just demonstrated their numerous advantages over organic dyes in bioimaging and diagnostics. One of characteristics of QDs is a very large cross section of their twophoton absorption. A common approach to biodetection by means of QDs is to use monoclonal antibodies (mAbs) for targeting. Recently, we have engineered ultrasmall diagnostic nanoprobes (sdAb-QD) based on highly oriented conjugates of QDs with the single-domain antibodies (sdAbs) against cancer biomarkers. With a molecular weight of only 13 kDa (12-fold smaller than full-size mAbs) and extreme stability and capacity to refolding, sdAbs are the smallest functional Ab fragments capable of binding antigens with affinities comparable to those of conventional Abs. Ultrasmall diagnostic sdAb-QD nanoprobes were engineered through oriented conjugation of QDs with sdAbs. This study is the first to demonstrate the possibility of immunohistochemical imaging of colon carcinoma biomarkers with sdAb-QD conjugates by means of two-photon excitation. The optimal excitation conditions for imaging of the markers in clinical samples with sdAb-QD nanoprobes have been determined. The absence of sample autofluorescence significantly improves the sensitivity of biomarker detection with the use of the two-photon excitation diagnostic setup.

  12. Oxide semiconductors

    CERN Document Server

    Svensson, Bengt G; Jagadish, Chennupati

    2013-01-01

    Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the ""Willardson and Beer"" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scient

  13. Semiconductor statistics

    CERN Document Server

    Blakemore, J S

    1962-01-01

    Semiconductor Statistics presents statistics aimed at complementing existing books on the relationships between carrier densities and transport effects. The book is divided into two parts. Part I provides introductory material on the electron theory of solids, and then discusses carrier statistics for semiconductors in thermal equilibrium. Of course a solid cannot be in true thermodynamic equilibrium if any electrical current is passed; but when currents are reasonably small the distribution function is but little perturbed, and the carrier distribution for such a """"quasi-equilibrium"""" co

  14. Radiation tolerance of amorphous semiconductors

    International Nuclear Information System (INIS)

    Nicolaides, R.V.; DeFeo, S.; Doremus, L.W.

    1976-01-01

    In an attempt to determine the threshold radiation damage in amorphous semiconductors, radiation tests were performed on amorphous semiconductor thin film materials and on threshold and memory devices. The influence of flash x-rays and neutron radiation upon the switching voltages, on- and off-state characteristics, dielectric response, optical transmission, absorption band edge and photoconductivity were measured prior to, during and following irradiation. These extensive tests showed the high radiation tolerance of amorphous semiconductor materials. Electrical and optical properties, other than photoconductivity, have a neutron radiation tolerance threshold above 10 17 nvt in the steady state and 10 14 nvt in short (50 μsec to 16 msec) pulses. Photoconductivity increases by 1 1 / 2 orders of magnitude at the level of 10 14 nvt (short pulses of 50 μsec). Super flash x-rays up to 5000 rads (Si), 20 nsec, do not initiate switching in off-state samples which are voltage biased up to 90 percent of the threshold voltage. Both memory and threshold amorphous devices are capable of switching on and off during nuclear radiation transients at least as high as 2 x 10 14 nvt in 50 μsec pulses

  15. [Primary, single-stage arterial switch operations at a newly-established, comprehensive congenital cardiac center performed in the neonatal age and beyond].

    Science.gov (United States)

    Király, László; Tamás, Csaba

    2015-06-21

    Outcome of arterial switch operation for transposition of the great arteries with/without ventricular septal defect is a service key-performance-indicator. The aim of the authors was to assess patient characteristics and parameters in the perioperative course. In the setting of a newly-established, comprehensive tertiary-care center, primary complete repair was performed including associated anomalies, e.g. transverse arch repairs. Patients with d-transposition were grouped according to coexistence of ventricular septal defect. 118 arterial switch operations were performed between 2007 and 2014 with 96.62% survival (114/118). Ventricular septal defect and repair of associated anomalies did not yield worse outcome. Left ventricular re-training with late presentation necessitated mechanical circulatory support for 4.5±1.5 days. D-transposition is suitable for standardization of clinical algorithm and surgical technique. Quality standards contribute to excellent outcomes, minimize complications, and serve as blueprint for other neonatal open-heart procedures. Availability of mechanical circulatory support is key for single-stage left ventricular re-training beyond the neonatal period.

  16. Biologically inspired flexible quasi-single-mode random laser: An integration of Pieris canidia butterfly wing and semiconductors

    Science.gov (United States)

    Wang, Cih-Su; Chang, Tsung-Yuan; Lin, Tai-Yuan; Chen, Yang-Fang

    2014-10-01

    Quasi-periodic structures of natural biomaterial membranes have great potentials to serve as resonance cavities to generate ecological friendly optoelectronic devices with low cost. To achieve the first attempt for the illustration of the underlying principle, the Pieris canidia butterfly wing was embedded with ZnO nanoparticles. Quite interestingly, it is found that the bio-inspired quasi-single-mode random laser can be achieved by the assistance of the skeleton of the membrane, in which ZnO nanoparticles act as emitting gain media. Such unique characteristics can be interpreted well by the Fabry-Perot resonance existing in the window-like quasi-periodic structure of butterfly wing. Due to the inherently promising flexibility of butterfly wing membrane, the laser action can still be maintained during the bending process. Our demonstrated approach not only indicates that the natural biological structures can provide effective scattering feedbacks but also pave a new avenue towards designing bio-controlled photonic devices.

  17. Biologically inspired flexible quasi-single-mode random laser: an integration of Pieris canidia butterfly wing and semiconductors.

    Science.gov (United States)

    Wang, Cih-Su; Chang, Tsung-Yuan; Lin, Tai-Yuan; Chen, Yang-Fang

    2014-10-23

    Quasi-periodic structures of natural biomaterial membranes have great potentials to serve as resonance cavities to generate ecological friendly optoelectronic devices with low cost. To achieve the first attempt for the illustration of the underlying principle, the Pieris canidia butterfly wing was embedded with ZnO nanoparticles. Quite interestingly, it is found that the bio-inspired quasi-single-mode random laser can be achieved by the assistance of the skeleton of the membrane, in which ZnO nanoparticles act as emitting gain media. Such unique characteristics can be interpreted well by the Fabry-Perot resonance existing in the window-like quasi-periodic structure of butterfly wing. Due to the inherently promising flexibility of butterfly wing membrane, the laser action can still be maintained during the bending process. Our demonstrated approach not only indicates that the natural biological structures can provide effective scattering feedbacks but also pave a new avenue towards designing bio-controlled photonic devices.

  18. The drift-diffusion interpretation of the electron current within the organic semiconductor characterized by the bulk single energy trap level

    Science.gov (United States)

    Cvikl, B.

    2010-01-01

    The closed solution for the internal electric field and the total charge density derived in the drift-diffusion approximation for the model of a single layer organic semiconductor structure characterized by the bulk shallow single trap-charge energy level is presented. The solutions for two examples of electric field boundary conditions are tested on room temperature current density-voltage data of the electron conducting aluminum/tris(8-hydroxyquinoline aluminum/calcium structure [W. Brütting et al., Synth. Met. 122, 99 (2001)] for which jexp∝Va3.4, within the interval of bias 0.4 V≤Va≤7. In each case investigated the apparent electron mobility determined at given bias is distributed within a given, finite interval of values. The bias dependence of the logarithm of their lower limit, i.e., their minimum values, is found to be in each case, to a good approximation, proportional to the square root of the applied electric field. On account of the bias dependence as incorporated in the minimum value of the apparent electron mobility the spatial distribution of the organic bulk electric field as well as the total charge density turn out to be bias independent. The first case investigated is based on the boundary condition of zero electric field at the electron injection interface. It is shown that for minimum valued apparent mobilities, the strong but finite accumulation of electrons close to the anode is obtained, which characterize the inverted space charge limited current (SCLC) effect. The second example refers to the internal electric field allowing for self-adjustment of its boundary values. The total electron charge density is than found typically to be of U shape, which may, depending on the parameters, peak at both or at either Alq3 boundary. It is this example in which the proper SCLC effect is consequently predicted. In each of the above two cases, the calculations predict the minimum values of the electron apparent mobility, which substantially

  19. Semiconductor Detectors

    International Nuclear Information System (INIS)

    Cortina, E.

    2007-01-01

    Particle detectors based on semiconductor materials are among the few devices used for particle detection that are available to the public at large. In fact we are surrounded by them in our daily lives: they are used in photoelectric cells for opening doors, in digital photographic and video camera, and in bar code readers at supermarket cash registers. (Author)

  20. Quantum optics with semiconductor nanostructures

    CERN Document Server

    Jahnke, Frank

    2012-01-01

    A guide to the theory, application and potential of semiconductor nanostructures in the exploration of quantum optics. It offers an overview of resonance fluorescence emission.$bAn understanding of the interaction between light and matter on a quantum level is of fundamental interest and has many applications in optical technologies. The quantum nature of the interaction has recently attracted great attention for applications of semiconductor nanostructures in quantum information processing. Quantum optics with semiconductor nanostructures is a key guide to the theory, experimental realisation, and future potential of semiconductor nanostructures in the exploration of quantum optics. Part one provides a comprehensive overview of single quantum dot systems, beginning with a look at resonance fluorescence emission. Quantum optics with single quantum dots in photonic crystal and micro cavities are explored in detail, before part two goes on to review nanolasers with quantum dot emitters. Light-matter interaction...

  1. Semiconductor Nanocrystals for Biological Imaging

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Aihua; Gu, Weiwei; Larabell, Carolyn; Alivisatos, A. Paul

    2005-06-28

    Conventional organic fluorophores suffer from poor photo stability, narrow absorption spectra and broad emission feature. Semiconductor nanocrystals, on the other hand, are highly photo-stable with broad absorption spectra and narrow size-tunable emission spectra. Recent advances in the synthesis of these materials have resulted in bright, sensitive, extremely photo-stable and biocompatible semiconductor fluorophores. Commercial availability facilitates their application in a variety of unprecedented biological experiments, including multiplexed cellular imaging, long-term in vitro and in vivo labeling, deep tissue structure mapping and single particle investigation of dynamic cellular processes. Semiconductor nanocrystals are one of the first examples of nanotechnology enabling a new class of biomedical applications.

  2. A linear 180 nm SOI CMOS antenna switch module using integrated passive device filters for cellular applications

    International Nuclear Information System (INIS)

    Cui Jie; Chen Lei; Liu Yi; Zhao Peng; Niu Xu

    2014-01-01

    A broadband monolithic linear single pole, eight throw (SP8T) switch has been fabricated in 180 nm thin film silicon-on-insulator (SOI) CMOS technology with a quad-band GSM harmonic filter in integrated passive devices (IPD) technology, which is developed for cellular applications. The antenna switch module (ASM) features 1.2 dB insertion loss with filter on 2G bands and 0.4 dB insertion loss in 3G bands, less than −45 dB isolation and maximum −103 dB intermodulation distortion for mobile front ends by applying distributed architecture and adaptive supply voltage generator. (semiconductor integrated circuits)

  3. Developmental switching in Physarum polycephalum : Petri net analysis of single cell trajectories of gene expression indicates responsiveness and genetic plasticity of the Waddington quasipotential landscape

    International Nuclear Information System (INIS)

    Werthmann, Britta; Marwan, Wolfgang

    2017-01-01

    The developmental switch to sporulation in Physarum polycephalum is a phytochrome-mediated far-red light-induced cell fate decision that synchronously encompasses the entire multinucleate plasmodial cell and is associated with extensive reprogramming of the transcriptome. By repeatedly taking samples of single cells after delivery of a light stimulus pulse, we analysed differential gene expression in two mutant strains and in a heterokaryon of the two strains all of which display a different propensity for making the cell fate decision. Multidimensional scaling of the gene expression data revealed individually different single cell trajectories eventually leading to sporulation. Characterization of the trajectories as walks through states of gene expression discretized by hierarchical clustering allowed the reconstruction of Petri nets that model and predict the observed behavior. Structural analyses of the Petri nets indicated stimulus- and genotype-dependence of both, single cell trajectories and of the quasipotential landscape through which these trajectories are taken. The Petri net-based approach to the analysis and decomposition of complex cellular responses and of complex mutant phenotypes may provide a scaffold for the data-driven reconstruction of causal molecular mechanisms that shape the topology of the quasipotential landscape. (paper)

  4. Developmental switching in Physarum polycephalum: Petri net analysis of single cell trajectories of gene expression indicates responsiveness and genetic plasticity of the Waddington quasipotential landscape

    Science.gov (United States)

    Werthmann, Britta; Marwan, Wolfgang

    2017-11-01

    The developmental switch to sporulation in Physarum polycephalum is a phytochrome-mediated far-red light-induced cell fate decision that synchronously encompasses the entire multinucleate plasmodial cell and is associated with extensive reprogramming of the transcriptome. By repeatedly taking samples of single cells after delivery of a light stimulus pulse, we analysed differential gene expression in two mutant strains and in a heterokaryon of the two strains all of which display a different propensity for making the cell fate decision. Multidimensional scaling of the gene expression data revealed individually different single cell trajectories eventually leading to sporulation. Characterization of the trajectories as walks through states of gene expression discretized by hierarchical clustering allowed the reconstruction of Petri nets that model and predict the observed behavior. Structural analyses of the Petri nets indicated stimulus- and genotype-dependence of both, single cell trajectories and of the quasipotential landscape through which these trajectories are taken. The Petri net-based approach to the analysis and decomposition of complex cellular responses and of complex mutant phenotypes may provide a scaffold for the data-driven reconstruction of causal molecular mechanisms that shape the topology of the quasipotential landscape.

  5. Manufacture of Radio Frequency Micromachined Switches with Annealing

    OpenAIRE

    Lin, Cheng-Yang; Dai, Ching-Liang

    2014-01-01

    The fabrication and characterization of a radio frequency (RF) micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW) lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS) process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspe...

  6. Novel Family of Single-Phase Modified Impedance-Source Buck-Boost Multilevel Inverters with Reduced Switch Count

    DEFF Research Database (Denmark)

    Husev, Oleksandr; Strzelecki, Ryszard; Blaabjerg, Frede

    2016-01-01

    This paper describes novel single-phase solutions with increased inverter voltage levels derived by means of a nonstandard inverter configuration and impedance source networks. Operation principles based on special modulation techniques are presented. Detailed component design guidelines along wi...... with simulation and experimental verification are also provided. Possible application fields are discussed, as well as advantages and disadvantages. Finally, future studies are addressed for the new solutions....

  7. Next Generation Semiconductor Based Sequencing of the Donkey (Equus asinus) Genome Provided Comparative Sequence Data against the Horse Genome and a Few Millions of Single Nucleotide Polymorphisms

    Science.gov (United States)

    Bertolini, Francesca; Scimone, Concetta; Geraci, Claudia; Schiavo, Giuseppina; Utzeri, Valerio Joe; Chiofalo, Vincenzo; Fontanesi, Luca

    2015-01-01

    Few studies investigated the donkey (Equus asinus) at the whole genome level so far. Here, we sequenced the genome of two male donkeys using a next generation semiconductor based sequencing platform (the Ion Proton sequencer) and compared obtained sequence information with the available donkey draft genome (and its Illumina reads from which it was originated) and with the EquCab2.0 assembly of the horse genome. Moreover, the Ion Torrent Personal Genome Analyzer was used to sequence reduced representation libraries (RRL) obtained from a DNA pool including donkeys of different breeds (Grigio Siciliano, Ragusano and Martina Franca). The number of next generation sequencing reads aligned with the EquCab2.0 horse genome was larger than those aligned with the draft donkey genome. This was due to the larger N50 for contigs and scaffolds of the horse genome. Nucleotide divergence between E. caballus and E. asinus was estimated to be ~ 0.52-0.57%. Regions with low nucleotide divergence were identified in several autosomal chromosomes and in the whole chromosome X. These regions might be evolutionally important in equids. Comparing Y-chromosome regions we identified variants that could be useful to track donkey paternal lineages. Moreover, about 4.8 million of single nucleotide polymorphisms (SNPs) in the donkey genome were identified and annotated combining sequencing data from Ion Proton (whole genome sequencing) and Ion Torrent (RRL) runs with Illumina reads. A higher density of SNPs was present in regions homologous to horse chromosome 12, in which several studies reported a high frequency of copy number variants. The SNPs we identified constitute a first resource useful to describe variability at the population genomic level in E. asinus and to establish monitoring systems for the conservation of donkey genetic resources. PMID:26151450

  8. Next Generation Semiconductor Based Sequencing of the Donkey (Equus asinus Genome Provided Comparative Sequence Data against the Horse Genome and a Few Millions of Single Nucleotide Polymorphisms.

    Directory of Open Access Journals (Sweden)

    Francesca Bertolini

    Full Text Available Few studies investigated the donkey (Equus asinus at the whole genome level so far. Here, we sequenced the genome of two male donkeys using a next generation semiconductor based sequencing platform (the Ion Proton sequencer and compared obtained sequence information with the available donkey draft genome (and its Illumina reads from which it was originated and with the EquCab2.0 assembly of the horse genome. Moreover, the Ion Torrent Personal Genome Analyzer was used to sequence reduced representation libraries (RRL obtained from a DNA pool including donkeys of different breeds (Grigio Siciliano, Ragusano and Martina Franca. The number of next generation sequencing reads aligned with the EquCab2.0 horse genome was larger than those aligned with the draft donkey genome. This was due to the larger N50 for contigs and scaffolds of the horse genome. Nucleotide divergence between E. caballus and E. asinus was estimated to be ~ 0.52-0.57%. Regions with low nucleotide divergence were identified in several autosomal chromosomes and in the whole chromosome X. These regions might be evolutionally important in equids. Comparing Y-chromosome regions we identified variants that could be useful to track donkey paternal lineages. Moreover, about 4.8 million of single nucleotide polymorphisms (SNPs in the donkey genome were identified and annotated combining sequencing data from Ion Proton (whole genome sequencing and Ion Torrent (RRL runs with Illumina reads. A higher density of SNPs was present in regions homologous to horse chromosome 12, in which several studies reported a high frequency of copy number variants. The SNPs we identified constitute a first resource useful to describe variability at the population genomic level in E. asinus and to establish monitoring systems for the conservation of donkey genetic resources.

  9. Semiconductor sensors

    International Nuclear Information System (INIS)

    Hartmann, Frank

    2011-01-01

    Semiconductor sensors have been around since the 1950s and today, every high energy physics experiment has one in its repertoire. In Lepton as well as Hadron colliders, silicon vertex and tracking detectors led to the most amazing physics and will continue doing so in the future. This contribution tries to depict the history of these devices exemplarily without being able to honor all important developments and installations. The current understanding of radiation damage mechanisms and recent R and D topics demonstrating the future challenges and possible technical solutions for the SLHC detectors are presented. Consequently semiconductor sensor candidates for an LHC upgrade and a future linear collider are also briefly introduced. The work presented here is a collage of the work of many individual silicon experts spread over several collaborations across the world.

  10. Semiconductor Optics

    CERN Document Server

    Klingshirn, Claus F

    2012-01-01

    This updated and enlarged new edition of Semiconductor Optics provides an introduction to and an overview of semiconductor optics from the IR through the visible to the UV, including linear and nonlinear optical properties, dynamics, magneto and electrooptics, high-excitation effects and laser processes, some applications, experimental techniques and group theory. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered extend from physics to materials science and optoelectronics. Significantly updated chapters add coverage of current topics such as electron hole plasma, Bose condensation of excitons and meta materials. Over 120 problems, chapter introductions and a detailed index make it the key textbook for graduate students in physics. The mathematics is kept as elementary as possible, sufficient for an intuitive understanding of the experimental results and techniques treated. The subjects covered ...

  11. Semiconductor annealing

    International Nuclear Information System (INIS)

    Young, J.M.; Scovell, P.D.

    1982-01-01

    A process for annealing crystal damage in ion implanted semiconductor devices in which the device is rapidly heated to a temperature between 450 and 900 0 C and allowed to cool. It has been found that such heating of the device to these relatively low temperatures results in rapid annealing. In one application the device may be heated on a graphite element mounted between electrodes in an inert atmosphere in a chamber. (author)

  12. Persistence and extinction of a stochastic single-specie model under regime switching in a polluted environment.

    Science.gov (United States)

    Liu, Meng; Wang, Ke

    2010-06-07

    A new single-species model disturbed by both white noise and colored noise in a polluted environment is developed and analyzed. Sufficient criteria for extinction, stochastic nonpersistence in the mean, stochastic weak persistence in the mean, stochastic strong persistence in the mean and stochastic permanence of the species are established. The threshold between stochastic weak persistence in the mean and extinction is obtained. The results show that both white and colored environmental noises have sufficient effect to the survival results. Copyright (c) 2010 Elsevier Ltd. All rights reserved.

  13. Battery Management System—Balancing Modularization Based on a Single Switched Capacitor and Bi-Directional DC/DC Converter with the Auxiliary Battery

    Directory of Open Access Journals (Sweden)

    Mohamed Daowd

    2014-04-01

    Full Text Available Lithium-based batteries are considered as the most advanced batteries technology, which can be designed for high energy or high power storage systems. However, the battery cells are never fully identical due to the fabrication process, surrounding environment factors and differences between the cells tend to grow if no measures are taken. In order to have a high performance battery system, the battery cells should be continuously balanced for maintain the variation between the cells as small as possible. Without an appropriate balancing system, the individual cell voltages will differ over time and battery system capacity will decrease quickly. These issues will limit the electric range of the electric vehicle (EV and some cells will undergo higher stress, whereby the cycle life of these cells will be shorter. Quite a lot of cell balancing/equalization topologies have been previously proposed. These balancing topologies can be categorized into passive and active balancing. Active topologies are categorized according to the active element used for storing the energy such as capacitor and/or inductive component as well as controlling switches or converters. This paper proposes an intelligent battery management system (BMS including a battery pack charging and discharging control with a battery pack thermal management system. The BMS user input/output interfacing. The battery balancing system is based on battery pack modularization architecture. The proposed modularized balancing system has different equalization systems that operate inside and outside the modules. Innovative single switched capacitor (SSC control strategy is proposed to balance between the battery cells in the module (inside module balancing, IMB. Novel utilization of isolated bidirectional DC/DC converter (IBC is proposed to balance between the modules with the aid of the EV auxiliary battery (AB. Finally an experimental step-up has been implemented for the validation of the

  14. Design and Optimization of AlN based RF MEMS Switches

    Science.gov (United States)

    Hasan Ziko, Mehadi; Koel, Ants

    2018-05-01

    Radio frequency microelectromechanical system (RF MEMS) switch technology might have potential to replace the semiconductor technology in future communication systems as well as communication satellites, wireless and mobile phones. This study is to explore the possibilities of RF MEMS switch design and optimization with aluminium nitride (AlN) thin film as the piezoelectric actuation material. Achieving low actuation voltage and high contact force with optimal geometry using the principle of piezoelectric effect is the main motivation for this research. Analytical and numerical modelling of single beam type RF MEMS switch used to analyse the design parameters and optimize them for the minimum actuation voltage and high contact force. An analytical model using isotropic AlN material properties used to obtain the optimal parameters. The optimized geometry of the device length, width and thickness are 2000 µm, 500 µm and 0.6 µm respectively obtained for the single beam RF MEMS switch. Low actuation voltage and high contact force with optimal geometry are less than 2 Vand 100 µN obtained by analytical analysis. Additionally, the single beam RF MEMS switch are optimized and validated by comparing the analytical and finite element modelling (FEM) analysis.

  15. Pseudospark switches

    International Nuclear Information System (INIS)

    Billault, P.; Riege, H.; Gulik, M. van; Boggasch, E.; Frank, K.

    1987-01-01

    The pseudospark discharge is bound to a geometrical structure which is particularly well suited for switching high currents and voltages at high power levels. This type of discharge offers the potential for improvement in essentially all areas of switching operation: peak current and current density, current rise, stand-off voltage, reverse current capability, cathode life, and forward drop. The first pseudospark switch was built at CERN at 1981. Since then, the basic switching characteristics of pseudospark chambers have been studied in detail. The main feature of a pseudospark switch is the confinement of the discharge plasma to the device axis. The current transition to the hollow electrodes is spread over a rather large surface area. Another essential feature is the easy and precise triggering of the pseudospark switch from the interior of the hollow electrodes, relatively far from the main discharge gap. Nanosecond delay and jitter values can be achieved with trigger energies of less than 0.1 mJ, although cathode heating is not required. Pseudospark gaps may cover a wide range of high-voltage, high-current, and high-pulse-power switching at repetition rates of many kilohertz. This report reviews the basic researh on pseudospark switches which has been going on at CERN. So far, applications have been developed in the range of thyratron-like medium-power switches at typically 20 to 40 kV and 0.5 to 10 kA. High-current pseudospark switches have been built for a high-power 20 kJ pulse generator which is being used for long-term tests of plasma lenses developed for the future CERN Antiproton Collector (ACOL). The high-current switches have operated for several hundred thousand shots, with 20 to 50 ns jitter at 16 kV charging voltage and more than 100 kA peak current amplitude. (orig.)

  16. Progress in semiconductor laser diodes: SPIE volume 723

    International Nuclear Information System (INIS)

    Eichen, E.

    1987-01-01

    This book contains proceedings arranged under the following session headings: High power diode lasers; single emitters and arrays; Ultrahigh speed modulation of semiconductor diode lasers; Coherence and linewidth stabilized semiconductor lasers; and Growth, fabrication, and evaluation of laser diodes

  17. CCST [Center for Compound Semiconductor Technology] research briefs

    International Nuclear Information System (INIS)

    Zipperian, T.E.; Voelker, E.R.

    1989-12-01

    This paper discusses the following topics: theoretical predictions of valence and conduction band offsets in III-V semiconductors; reflectance modulation of a semiconductor superlattice optical mirror; magnetoquantum oscillations of the phonon-drag thermoelectric power in quantum wells; correlation between photoluminescence line shape and device performance of p-channel strained-layer materials; control of threading dislocations in heteroepitaxial structures; improved growth of CdTe on GaAs by patterning; role of structure threading dislocations in relaxation of highly strained single-quantum-well structures; InAlAs growth optimization using reflection mass spectrometry; nonvolatile charge storage in III-V heterostructures; optically triggered thyristor switches; InAsSb strained-layer superlattice infrared detectors with high detectivities; resonant periodic gain surface-emitting semiconductor lasers; performance advantages of strained-quantum-well lasers in AlGaAs/InGaAs; optical integrated circuit for phased-array radar antenna control; and deposition and novel device fabrication from Tl 2 Ca 2 Ba 2 Cu 3 O y thin films

  18. Apparatus for testing semiconductor devices and capacitors

    International Nuclear Information System (INIS)

    York, R.A.

    1984-01-01

    An apparatus is provided for testing semiconductor devices. The apparatus tests the impedance of the semiconductor devices in both conducting and non-conducting states to detect semiconductors whose impedance in the conducting state is too high or whose impedance in the non-conducting state is too low. The apparatus uses a battery source for low voltage d.c. The circuitry for detecting when the impedance is too high in the conducting state includes a lamp in series with the battery source and the semiconductor device, whereby the impedance of the semiconductor device determines whether sufficient current will flow through the lamp to cause the lamp to illuminate. A d.c. to d.c. converter is provided to boost the voltage from the battery source to a relatively high voltage d.c. The relatively high voltage d.c. can be connected by a switch to circuitry for detecting when the impedance of the semiconductor device in the non-conducting state is too low. The circuitry for detecting when the impedance of the semiconductor device is too low includes a resistor which senses the current flowing in the device and converts the current into a voltage proportional to the leakage current. This voltage is then compared against a fixed reference. Further circuitry is provided for providing a visual indication when the voltage representative of leakage in relation to the reference signal indicates that there is excessive current flow through the semiconductor device

  19. Semiconductor annealing

    International Nuclear Information System (INIS)

    Young, J.M.; Scovell, P.D.

    1981-01-01

    A process for annealing crystal damage in ion implanted semiconductor devices is described in which the device is rapidly heated to a temperature between 450 and 600 0 C and allowed to cool. It has been found that such heating of the device to these relatively low temperatures results in rapid annealing. In one application the device may be heated on a graphite element mounted between electrodes in an inert atmosphere in a chamber. The process may be enhanced by the application of optical radiation from a Xenon lamp. (author)

  20. Switch from unboosted protease inhibitor to a single-tablet regimen containing rilpivirine improves cholesterol and triglycerides.

    Science.gov (United States)

    Di Biagio, Antonio; Riccardi, Niccolò; Taramasso, Lucia; Capetti, Amedeo; Cenderello, Giovanni; Signori, Alessio; Vitiello, Paola; Guerra, Michele; de Socio, Giuseppe Vittorio; Cassola, Giovanni; Quirino, Tiziano; Viscoli, Claudio

    2016-11-01

    This study aimed to evaluate the efficacy, tolerability and potential savings of combined antiretroviral therapy (cART) simplification from an unboosted protease inhibitor (PI) regimen with atazanavir or fosamprenavir to a single-tablet regimen (STR) based on rilpivirine/emtricitabine/tenofovir disoproxil fumarate (RPV/FTC/TDF) among HIV-1-infected patients with HIV-1 RNA triglycerides, bilirubin, glycaemia, creatinine and physical examination were performed at baseline and at scheduled follow-up. All patient costs were calculated and were estimated for 52 weeks of therapy. Fifty-one patients were enrolled [28 male (54.9%)]. At baseline, 30 patients (58.8%) were treated with FTC/TDF, 20 (39.2%) with abacavir/lamivudine and 1 (2.0%) with lamivudine/zidovudine. Thirty-three patients (64.7%) received atazanavir. All patients maintained HIV-RNA triglycerides decreased from 124 mg/dL (range, 39-625) at enrolment to 108.7 mg/dL (range, 39-561) at study end (P = 0.25). At baseline, mean cholesterol was 172.8 ± 38.1 mg/dL and decreased to 161.9 ± 38.6 mg/dL (P = 0.038); likewise, median total bilirubin decreased from 1.07 mg/dL (range, 0.2-4.7) to 0.6 mg/dL (range, 0.13-3.1) (P triglycerides, cholesterol and cART-related costs. Copyright © 2016 Elsevier B.V. and International Society of Chemotherapy. All rights reserved.

  1. Magnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bihler, Christoph

    2009-04-15

    In this thesis we investigated in detail the properties of Ga{sub 1-x}Mn{sub x}As, Ga{sub 1-x}Mn{sub x}P, and Ga{sub 1-x}Mn{sub x}N dilute magnetic semiconductor thin films with a focus on the magnetic anisotropy and the changes of their properties upon hydrogenation. We applied two complementary spectroscopic techniques to address the position of H in magnetic semiconductors: (i) Electron paramagnetic resonance, which provides direct information on the symmetry of the crystal field of the Mn{sup 2+} atoms and (ii) x-ray absorption fine structure analysis which allows to probe the local crystallographic neighborhood of the absorbing Mn atom via analysing the fine structure at the Mn K absorption edge. Finally, we discussed the obstacles that have to be overcome to achieve Curie temperatures above the current maximum in Ga{sub 1-x}Mn{sub x}As of 185 K. Here, we outlined in detail the generic problem of the formation of precipitates at the example of Ge:MN. (orig.)

  2. Wide Bandgap Extrinsic Photoconductive Switches

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, James S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2013-07-03

    Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6HSiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators.

  3. neutron-Induced Failures in semiconductor Devices

    Energy Technology Data Exchange (ETDEWEB)

    Wender, Stephen Arthur [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-03-13

    Single Event Effects are a very significant failure mode in modern semiconductor devices that may limit their reliability. Accelerated testing is important for semiconductor industry. Considerable more work is needed in this field to mitigate the problem. Mitigation of this problem will probably come from Physicists and Electrical Engineers working together

  4. Superconducting Switch for Fast On-Chip Routing of Quantum Microwave Fields

    Science.gov (United States)

    Pechal, M.; Besse, J.-C.; Mondal, M.; Oppliger, M.; Gasparinetti, S.; Wallraff, A.

    2016-08-01

    A switch capable of routing microwave signals at cryogenic temperatures is a desirable component for state-of-the-art experiments in many fields of applied physics, including but not limited to quantum-information processing, communication, and basic research in engineered quantum systems. Conventional mechanical switches provide low insertion loss but disturb operation of dilution cryostats and the associated experiments by heat dissipation. Switches based on semiconductors or microelectromechanical systems have a lower thermal budget but are not readily integrated with current superconducting circuits. Here we design and test an on-chip switch built by combining tunable transmission-line resonators with microwave beam splitters. The device is superconducting and as such dissipates a negligible amount of heat. It is compatible with current superconducting circuit fabrication techniques, operates with a bandwidth exceeding 100 MHz, is capable of handling photon fluxes on the order of 1 05 μ s-1 , equivalent to powers exceeding -90 dBm , and can be switched within approximately 6-8 ns. We successfully demonstrate operation of the device in the quantum regime by integrating it on a chip with a single-photon source and using it to route nonclassical itinerant microwave fields at the single-photon level.

  5. Semiconductor Laser Measurements Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Semiconductor Laser Measurements Laboratory is equipped to investigate and characterize the lasing properties of semiconductor diode lasers. Lasing features such...

  6. Photonic Switching Devices Using Light Bullets

    Science.gov (United States)

    Goorjian, Peter M. (Inventor)

    1999-01-01

    A unique ultra-fast, all-optical switching device or switch is made with readily available, relatively inexpensive, highly nonlinear optical materials. which includes highly nonlinear optical glasses, semiconductor crystals and/or multiple quantum well semiconductor materials. At the specified wavelengths. these optical materials have a sufficiently negative group velocity dispersion and high nonlinear index of refraction to support stable light bullets. The light bullets counter-propagate through, and interact within the waveguide to selectively change each others' directions of propagation into predetermined channels. In one embodiment, the switch utilizes a rectangularly planar slab waveguide. and further includes two central channels and a plurality of lateral channels for guiding the light bullets into and out of the waveguide. An advantage of the present all-optical switching device lies in its practical use of light bullets, thus preventing the degeneration of the pulses due to dispersion and diffraction at the front and back of the pulses. Another advantage of the switching device is the relative insensitivity of the collision process to the time difference in which the counter-propagating pulses enter the waveguide. since. contrary to conventional co-propagating spatial solitons, the relative phase of the colliding pulses does not affect the interaction of these pulses. Yet another feature of the present all-optical switching device is the selection of the light pulse parameters which enables the generation of light bullets in nonlinear optical materials. including highly nonlinear optical glasses and semiconductor materials such as semiconductor crystals and/or multiple quantum well semiconductor materials.

  7. Porous and Nanoporous Semiconductors and Emerging Applications

    Directory of Open Access Journals (Sweden)

    Helmut Föll

    2006-01-01

    Full Text Available Pores in single-crystalline semiconductors can be produced in a wide range of geometries and morphologies, including the “nanometer” regime. Porous semiconductors may have properties completely different from the bulk, and metamaterials with, for example, optical properties not encountered in natural materials are emerging. Possible applications of porous semiconductors include various novel sensors, but also more “exotic” uses as, for example, high explosives or electrodes for micro-fuel cells. The paper briefly reviews pore formation (including more applied aspects of large area etching, properties of porous semiconductors, and emerging applications.

  8. High mobility emissive organic semiconductor

    Science.gov (United States)

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

    2015-01-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V−1 s−1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m−2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics. PMID:26620323

  9. All-optical devices for ultrafast packet switching

    DEFF Research Database (Denmark)

    Dorren, H.J.S.; HerreraDorren, J.; Raz, O.

    2007-01-01

    We discuss integrated devices for all-optical packet switching. We focus on monolithically integrated all-optical flip-flops, ultra-fast semiconductor based wavelength converters and explain the operation principles. Finally, a 160 Gb/s all-optical packet switching experiment over 110 km of field...

  10. Electrowetting on semiconductors

    Science.gov (United States)

    Palma, Cesar; Deegan, Robert

    2015-01-01

    Applying a voltage difference between a conductor and a sessile droplet sitting on a thin dielectric film separating it from the conductor will cause the drop to spread. When the conductor is a good metal, the change of the drop's contact angle due to the voltage is given by the Young-Lippmann (YL) equation. Here, we report experiments with lightly doped, single crystal silicon as the conductive electrode. We derive a modified YL equation that includes effects due to the semiconductor and contact line pinning. We show that light induces a non-reversible wetting transition, and that our model agrees well with our experimental results.

  11. Caffeine improves anticipatory processes in task switching

    NARCIS (Netherlands)

    Tieges, Zoe; Snel, Jan; Kok, Albert; Wijnen, Jasper G.; Lorist, Monicque M.; Ridderinkhof, K. Richard

    We studied the effects of moderate amounts of caffeine on task switching and task maintenance using mixed-task (AABB) blocks, in which participants alternated predictably between two tasks, and single-task (AAAA, BBBB) blocks. Switch costs refer to longer reaction times (RT) on task switch trials

  12. Bootstrapped Low-Voltage Analog Switches

    DEFF Research Database (Denmark)

    Steensgaard-Madsen, Jesper

    1999-01-01

    Novel low-voltage constant-impedance analog switch circuits are proposed. The switch element is a single MOSFET, and constant-impedance operation is obtained using simple circuits to adjust the gate and bulk voltages relative to the switched signal. Low-voltage (1-volt) operation is made feasible...

  13. A single-source solid-precursor method for making eco-friendly doped semiconductor nanoparticles emitting multi-color luminescence.

    Science.gov (United States)

    Manzoor, K; Aditya, V; Vadera, S R; Kumar, N; Kutty, T R N

    2007-02-01

    A novel synthesis method is presented for the preparation of eco-friendly, doped semiconductor nanocrystals encapsulated within oxide-shells, both formed sequentially from a single-source solid-precursor. Highly luminescent ZnS nanoparticles, in situ doped with Cu(+)-Al3+ pairs and encapsulated with ZnO shells are prepared by the thermal decomposition of a solid-precursor compound, zinc sulfato-thiourea-oxyhydroxide, showing layered crystal structure. The precursor compound is prepared by an aqueous wet-chemical reaction involving necessary chemical reagents required for the precipitation, doping and inorganic surface capping of the nanoparticles. The elemental analysis (C, H, N, S, O, Zn), quantitative estimation of different chemical groups (SO4(2-) and NH4(-)) and infrared studies suggested that the precursor compound is formed by the intercalation of thiourea, and/or its derivatives thiocarbamate (CSNH2(-)), dithiocarbamate (CS2NH2(-)), etc., and ammonia into the gallery space of zinc-sulfato-oxyhydroxide corbel where the Zn(II) ions are both in the octahedral as well as tetrahedral coordination in the ratio 3 : 2 and the dopant ions are incorporated within octahedral voids. The powder X-ray diffraction of precursor compound shows high intensity basal reflection corresponding to the large lattice-plane spacing of d = 11.23 angstroms and the Rietveld analysis suggested orthorhombic structure with a = 9.71 angstroms, b = 12.48 angstroms, c = 26.43 angstroms, and beta = 90 degrees. Transmission electron microscopy studies show the presence of micrometer sized acicular monocrystallites with prismatic platy morphology. Controlled thermolysis of the solid-precursor at 70-110 degrees C leads to the collapse of layered structure due to the hydrolysis of interlayer thiourea molecules or its derivatives and the S2- ions liberated thereby reacts with the tetrahedral Zn(II) atoms leading to the precipitation of ZnS nanoparticles at the gallery space. During this process

  14. Semiconductor laser shearing interferometer

    International Nuclear Information System (INIS)

    Ming Hai; Li Ming; Chen Nong; Xie Jiaping

    1988-03-01

    The application of semiconductor laser on grating shearing interferometry is studied experimentally in the present paper. The method measuring the coherence of semiconductor laser beam by ion etching double frequency grating is proposed. The experimental result of lens aberration with semiconductor laser shearing interferometer is given. Talbot shearing interferometry of semiconductor laser is also described. (author). 2 refs, 9 figs

  15. Development of semiconductor electronics

    International Nuclear Information System (INIS)

    Bardeen, John.

    1977-01-01

    In 1931, Wilson applied Block's theory about the energy bands for the motion of electrons in a crystal lattice to semiconductors and showed that conduction can take place in two different ways, by electrons and by holes. Not long afterwards Frenkel showed that these carriers can flow by diffusion in a concentration gradient as well as under the influence of an electric field and wrote down equations for the current flow. The third major contribution, in the late 1930's was the explanation of rectification at a metalsemiconductor contact by Mott and more completely by Schottky. In late 1947 the first transistor of the point contact type was invented by Brattin, Shockley and Bardeen. Then after single crystals of Ge were grown, the junction transistor was developed by the same group. The first silicon transistors appeared in 1954. Then an important step was discovery of the planar transistor by Hoenri in 1960 which led to development of integrated circuits by 1962. Many transistors are produced by batch processing on a slice of silicon. Then in 1965 Mos (Metal-Oxide Semiconductor) transistor and in 1968 LSI (Large Scale Intergration circuits) were developed. Aside from electronic circuits, there are many other applications of semiconductors, including junction power rectifiers, junction luminescence (including lasers), solar batteries, radiation detectors, microwave oscillators and charged-coupled devices for computer memories and devices. One of the latest developments is a microprocessor with thousands of transistors and associated circuitry on a single small chip of silicon. It can be programmed to provide a variety of circuit functions, thus it is not necessary to go through the great expense of LSI's for each desired function, but to use standard microprocessors and program to do the job

  16. Ion implantation methods for semiconductor substrates

    International Nuclear Information System (INIS)

    Matsushita, T.; Mamine, T.; Hayashi, H.; Nishiyama, K.

    1980-01-01

    A method of ion implantation for controlling the life time of minority carriers in a semiconductor substrate and hence to reduce the temperature dependency of the life time, comprises implanting iron ions into an N type semiconductor substrate with a dosage of 10 10 to 10 15 ions cm -2 , and then heat-treating the implanted substrate at 850 0 to 1250 0 C. The method is applicable to the production of diodes, transistors, Si controlled rectifiers and gate controlled switching devices. (author)

  17. Integrating magnetism into semiconductor electronics

    Energy Technology Data Exchange (ETDEWEB)

    Zakharchenya, Boris P; Korenev, Vladimir L [A.F. Ioffe Physico-Technical Institute, Russian Academy of Sciences, St. Petersburg (Russian Federation)

    2005-06-30

    The view of a ferromagnetic-semiconducting hybrid structure as a single tunable system is presented. Based on an analysis of existing experiments it is shown that, contrary to a 'common sense', a nonmagnetic semiconductor is capable of playing an important role in controlling ferromagnetism. Magnetic properties of a hybrid (the hysteresis loop and the spatial orientation of magnetization) can be tuned both optically and electrically by utilizing semiconductor-making the hybrid an electronic-write-in and electronic-read-out elementary storage unit. (methodological notes)

  18. Integrating magnetism into semiconductor electronics

    International Nuclear Information System (INIS)

    Zakharchenya, Boris P; Korenev, Vladimir L

    2005-01-01

    The view of a ferromagnetic-semiconducting hybrid structure as a single tunable system is presented. Based on an analysis of existing experiments it is shown that, contrary to a 'common sense', a nonmagnetic semiconductor is capable of playing an important role in controlling ferromagnetism. Magnetic properties of a hybrid (the hysteresis loop and the spatial orientation of magnetization) can be tuned both optically and electrically by utilizing semiconductor-making the hybrid an electronic-write-in and electronic-read-out elementary storage unit. (methodological notes)

  19. Colossal change in thermopower with temperature-driven p-n-type conduction switching in La x Sr2-x TiFeO6 double perovskites

    Science.gov (United States)

    Roy, Pinku; Maiti, Tanmoy

    2018-02-01

    Double perovskite materials have been studied in detail by many researchers, as their magnetic and electronic properties can be controlled by the substitution of alkaline earth metals or lanthanides in the A site and transition metals in the B site. Here we report the temperature-driven, p-n-type conduction switching assisted, large change in thermopower in La3+-doped Sr2TiFeO6-based double perovskites. Stoichiometric compositions of La x Sr2-x TiFeO6 (LSTF) with 0  ⩽  x  ⩽  0.25 were synthesized by the solid-state reaction method. Rietveld refinement of room-temperature XRD data confirmed a single-phase solid solution with cubic crystal structure and Pm\\bar{3}m space group. From temperature-dependent electrical conductivity and Seebeck coefficient (S) studies it is evident that all the compositions underwent an intermediate semiconductor-to-metal transition before the semiconductor phase reappeared at higher temperature. In the process of semiconductor-metal-semiconductor transition, LSTF compositions demonstrated temperature-driven p-n-type conduction switching behavior. The electronic restructuring which occurs due to the intermediate metallic phase between semiconductor phases leads to the colossal change in S for LSTF oxides. The maximum drop in thermopower (ΔS ~ 2516 µV K-1) was observed for LSTF with x  =  0.1 composition. Owing to their enormous change in thermopower of the order of millivolts per kelvin, integrated with p-n-type resistance switching, these double perovskites can be used for various high-temperature multifunctional device applications such as diodes, sensors, switches, thermistors, thyristors, thermal runaway monitors etc. Furthermore, the conduction mechanisms of these oxides were explained by the small polaron hopping model.

  20. Switching Phenomena

    Science.gov (United States)

    Stanley, H. E.; Buldyrev, S. V.; Franzese, G.; Havlin, S.; Mallamace, F.; Mazza, M. G.; Kumar, P.; Plerou, V.; Preis, T.; Stokely, K.; Xu, L.

    One challenge of biology, medicine, and economics is that the systems treated by these serious scientific disciplines can suddenly "switch" from one behavior to another, even though they possess no perfect metronome in time. As if by magic, out of nothing but randomness one finds remarkably fine-tuned processes in time. The past century has, philosophically, been concerned with placing aside the human tendency to see the universe as a fine-tuned machine. Here we will address the challenge of uncovering how, through randomness (albeit, as we shall see, strongly correlated randomness), one can arrive at some of the many temporal patterns in physics, economics, and medicine and even begin to characterize the switching phenomena that enable a system to pass from one state to another. We discuss some applications of correlated randomness to understanding switching phenomena in various fields. Specifically, we present evidence from experiments and from computer simulations supporting the hypothesis that water's anomalies are related to a switching point (which is not unlike the "tipping point" immortalized by Malcolm Gladwell), and that the bubbles in economic phenomena that occur on all scales are not "outliers" (another Gladwell immortalization).

  1. Radial semiconductor drift chambers

    International Nuclear Information System (INIS)

    Rawlings, K.J.

    1987-01-01

    The conditions under which the energy resolution of a radial semiconductor drift chamber based detector system becomes dominated by the step noise from the detector dark current have been investigated. To minimise the drift chamber dark current attention should be paid to carrier generation at Si/SiO 2 interfaces. This consideration conflicts with the desire to reduce the signal risetime: a higher drift field for shorter signal pulses requires a larger area of SiO 2 . Calculations for the single shaping and pseudo Gaussian passive filters indicate that for the same degree of signal risetime sensitivity in a system dominated by the step noise from the detector dark current, the pseudo Gaussian filter gives only a 3% improvement in signal/noise and 12% improvement in rate capability compared with the single shaper performance. (orig.)

  2. Stable Caloric Intake and Continued Virologic Suppression for HIV-Positive Antiretroviral Treatment-Experienced Women After Switching to a Single-Tablet Regimen of Emtricitabine, Rilpivirine, and Tenofovir Disoproxil Fumarate.

    Science.gov (United States)

    Menezes, Prema; Mollan, Katie; Hoffman, Erin; Xie, Zimeng; Wills, Jennifer; Marcus, Cheryl; Rublein, John; Hudgens, Michael; Eron, Joseph J

    2018-05-02

    Benefits of switching to a single-tablet regimen (STR) of emtricitabine/rilpivirine/tenofovir (FTC/RPV/TDF) in virologically suppressed antiretroviral treatment (ART) experienced HIV-positive women include pregnancy category B rating and lack of clinically significant drug interactions between RPV and oral contraceptives. Unfortunately, studies involving switching to FTC/RPV/TDF enrolled fewer than 25% women. We undertook this 48-week study to assess the ability of virologically suppressed HIV-positive women switching to RPV STR to remain virologically suppressed and comply with the caloric intake requirement. HIV-positive women on ART with viral load phone calls on randomly chosen dates. For each 3-day food diary, the daily median caloric intake and median value for each macronutrient consumed concurrent with FTC/RPV/TDF were computed. Medication adherence was measured using a visual analog scale. We enrolled 33 women, 73% of whom were African American. At week 48, virologic suppression (HIV RNA phone call. Median kcal intake (food diary) did not change significantly from baseline (684 kcal) to week 48 (820 kcal); median change 102 kcal, p = .15. Women who reported noncompliance with a ≥400 kcal meal did not experience virologic failure. Significant concordance between caloric adherence and virologic suppression was not detected. Our study demonstrated that HIV-positive women who switched to STR FTC/RPV/TDF continued to experience virologic suppression and were readily able to comply with the recommended caloric intake requirement.

  3. Semiconductor nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Marstein Erik Stensrud

    2003-07-01

    This thesis presents a study of two material systems containing semiconductor nanocrystals, namely porous silicon (PSi) films and germanium (Ge) nanocrystals embedded in silicon dioxide (SiO2) films. The PSi films were made by anodic etching of silicon (Si) substrates in an electrolyte containing hydrofluoric acid. The PSi films were doped with erbium (Er) using two different doping methods. electrochemical doping and doping by immersing the PSi films in a solution containing Er. The resulting Er concentration profiles were investigated using scanning electron microscopy (SEN1) combined with energy dispersive X-ray analysis (EDS). The main subject of the work on PSi presented in this thesis was investigating and comparing these two doping methods. Ge nanocrystals were made by implanting Ge ions into Si02 films that were subsequently annealed. However. nanocrystal formation occurred only for certain sets of processing parameters. The dependence of the microstructure of the Ge implanted Si02 films on the processing parameters were therefore investigated. A range of methods were employed for these investigations, including transmission electron microscopy (TEM) combined with EDS, X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectroscopy (SIMS). The observed structures, ranging from Ge nanocrystals to voids with diameters of several tens of nanometers and Ge rich Si02 films without any nanocrystals is described. A model explaining the void formation is also presented. For certain sets of processing parameters. An accumulation of Ge at the Si-Si02 interface was observed. The effect of this accumulation on the electrical properties of MOS structures made from Ge implanted SiO2 films was investigated using CV-measurements. (Author)

  4. A high‐isolation switch based on a standard GaAs process

    DEFF Research Database (Denmark)

    Zhurbenko, Vitaliy

    2011-01-01

    The design and evaluation of an ultra‐wideband nonreflective single port single throw switch integrated circuit is described. The switch has a measured insertion loss of......The design and evaluation of an ultra‐wideband nonreflective single port single throw switch integrated circuit is described. The switch has a measured insertion loss of...

  5. Optical fiber switch

    Science.gov (United States)

    Early, James W.; Lester, Charles S.

    2002-01-01

    Optical fiber switches operated by electrical activation of at least one laser light modulator through which laser light is directed into at least one polarizer are used for the sequential transport of laser light from a single laser into a plurality of optical fibers. In one embodiment of the invention, laser light from a single excitation laser is sequentially transported to a plurality of optical fibers which in turn transport the laser light to separate individual remotely located laser fuel ignitors. The invention can be operated electro-optically with no need for any mechanical or moving parts, or, alternatively, can be operated electro-mechanically. The invention can be used to switch either pulsed or continuous wave laser light.

  6. Sub-kT/q subthreshold slope p-metal-oxide-semiconductor field-effect transistors with single-grained Pb(Zr,Ti)O3 featuring a highly reliable negative capacitance

    Science.gov (United States)

    Park, Jae Hyo; Joo, Seung Ki

    2016-03-01

    A reliable on/off switching with an sub-kT/q subthreshold slope (38 mV/dec at room temperature) is experimentally demonstrated with using selectively nucleated laterally crystallized single-grain Pb(Zr,Ti)O3 (PZT) ferroelectric and ZrTiO4 paraelectric thin-film. The combination of ferroelectric and paraelectric thin-film is enabled to form a negative capacitance (NC) at the weak inversion region. However, the PZT grain-boundary easily degrades the NC properties after switching the on/off more than 108 times. It is found that the polarization of PZT is diminished from the path of grain-boundary. Here, we effectively suppress the degradation of NC MOS-FET which did not showed any fatigue even after 108 on/off switching. At the request of the authors this article is retracted due to duplication of figures and significant overlap with other publications by the authors and because of concerns about the accuracy of the description of the devices and materials from which the reported results were obtained. The authors recognize that these represent serious errors and sincerely apologize for any inconvenience they may have caused. The article is retracted from the scientific record with effect from 17 February 2017.

  7. Fundamentals of semiconductor devices

    CERN Document Server

    Lindmayer, Joseph

    1965-01-01

    Semiconductor properties ; semiconductor junctions or diodes ; transistor fundamentals ; inhomogeneous impurity distributions, drift or graded-base transistors ; high-frequency properties of transistors ; band structure of semiconductors ; high current densities and mechanisms of carrier transport ; transistor transient response and recombination processes ; surfaces, field-effect transistors, and composite junctions ; additional semiconductor characteristics ; additional semiconductor devices and microcircuits ; more metal, insulator, and semiconductor combinations for devices ; four-pole parameters and configuration rotation ; four-poles of combined networks and devices ; equivalent circuits ; the error function and its properties ; Fermi-Dirac statistics ; useful physical constants.

  8. Materials growth and characterization of thermoelectric and resistive switching devices

    Science.gov (United States)

    Norris, Kate J.

    erbium monoantimonide (ErSb) thin films with thermal conductivities close to or slightly smaller than the alloy limit of the two ternary alloy hosts. Second we consider an ex-situ monitoring technique based on glancing-angle infrared-absorption used to determine small amounts of erbium antimonide (ErSb) deposited on an indium antimonide (InSb) layer, a concept for thermoelectric devices to scatter phonons. Thirdly we begin our discussion of nanowires with the selective area growth (SAG) of single crystalline indium phosphide (InP) nanopillars on an array of template segments composed of a stack of gold and amorphous silicon. Our approach enables flexible and scalable nanofabrication using industrially proven tools and a wide range of semiconductors on various non-semiconductor substrates. Then we examine the use of graphene to promote the growth of nanowire networks on flexible copper foil leading to the testing of nanowire network devices for thermoelectric applications and the concept of multi-stage devices. We present the ability to tailor current-voltage characteristics to fit a desired application of thermoelectric devices by using nanowire networks as building blocks that can be stacked vertically or laterally. Furthermore, in the study of our flexible nanowire network multi-stage devices, we discovered the presence of nonlinear current-voltage characteristics and discuss how this feature could be utilized to increase efficiency for thermoelectric devices. This work indicates that with sufficient volume and optimized doping, flexible nanowire networks could be a low cost semiconductor solution to our wasted heat challenge. Resistive switching devices are two terminal electrical resistance switches that retain a state of internal resistance based on the history of applied voltage and current. The occurrence of reversible resistance switching has been widely studied in a variety of material systems for applications including nonvolatile memory, logic circuits, and

  9. Controlled Quantum Operations of a Semiconductor Three-Qubit System

    Science.gov (United States)

    Li, Hai-Ou; Cao, Gang; Yu, Guo-Dong; Xiao, Ming; Guo, Guang-Can; Jiang, Hong-Wen; Guo, Guo-Ping

    2018-02-01

    In a specially designed semiconductor device consisting of three capacitively coupled double quantum dots, we achieve strong and tunable coupling between a target qubit and two control qubits. We demonstrate how to completely switch on and off the target qubit's coherent rotations by presetting two control qubits' states. A Toffoli gate is, therefore, possible based on these control effects. This research paves a way for realizing full quantum-logic operations in semiconductor multiqubit systems.

  10. Detection of single-nucleotide polymorphisms using an ON-OFF switching of regenerated biosensor based on a locked nucleic acid-integrated and toehold-mediated strand displacement reaction.

    Science.gov (United States)

    Gao, Zhong Feng; Ling, Yu; Lu, Lu; Chen, Ning Yu; Luo, Hong Qun; Li, Nian Bing

    2014-03-04

    Although various strategies have been reported for single-nucleotide polymorphisms (SNPs) detection, development of a time-saving, specific, and regenerated electrochemical sensing platform still remains a realistic goal. In this study, an ON-OFF switching of a regenerated biosensor based on a locked nucleic acid (LNA)-integrated and toehold-mediated strand displacement reaction technique is constructed for detection of SNPs. The LNA-integrated and methylene blue-labeled capture probe with an external toehold is designed to switch on the sensing system. The mutant-type DNA probe completes complementary with the capture probe to trigger the strand displacement reaction, which switches off the sensing system. However, when the single-base mismatched wild-type DNA probe is presented, the strand displacement reaction cannot be achieved; therefore, the sensing system still keeps the ON state. This DNA sensor is stable over five reuses. We further testify that the LNA-integrated sequence has better recognition ability for SNPs detection compared to the DNA-integrated sequence. Moreover, this DNA senor exhibits a remarkable discrimination capability of SNPs among abundant wild-type targets and 6000-fold (m/m) excess of genomic DNA. In addition, it is selective enough in complex and contaminant-ridden samples, such as human urine, soil, saliva, and beer. Overall, these results demonstrate that this reliable DNA sensor is easy to be fabricated, simple to operate, and stable enough to be readily regenerated.

  11. Analyses of resource reservation schemes for optical burst switching networks

    Science.gov (United States)

    Solanska, Michaela; Scholtz, Lubomir; Ladanyi, Libor; Mullerova, Jarmila

    2017-12-01

    With growing demands of Internet Protocol services for transmission capacity and speed, the Optical Burst Switching presents the solution for future high-speed optical networks. Optical Burst Switching is a technology for transmitting large amounts of data bursts through a transparent optical switching network. To successfully transmit bursts over OBS network and reach the destination node, resource reservation schemes have to be implemented to allocate resources and configure optical switches for that burst at each node. The one-way resource reservation schemes and the performance evaluation of reservation schemes are presented. The OBS network model is performed using OMNeT++ simulation environment. During the reservation of network resources, the optical cross-connect based on semiconductor optical amplifier is used as the core node. Optical switches based on semiconductor optical amplifiers are a promising technology for high-speed optical communication networks.

  12. Dual Z-Source Inverter With Three-Level Reduced Common-Mode Switching

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

    2007-01-01

    This paper presents the design of a dual Z-source inverter that can be used with either a single dc source or two isolated dc sources. Unlike traditional inverters, the integration of a properly designed Z-source network and semiconductor switches to the proposed dual inverter allows buck......-boost power conversion to be performed over a wide modulation range, with three-level output waveforms generated. The connection of an additional transformer to the inverter ac output also allows all generic wye-or delta-connected loads with three-wire or four-wire configuration to be supplied by the inverter....... Modulationwise, the dual inverter can be controlled using a carefully designed carrier-based pulsewidth-modulation (PWM) scheme that will always ensure balanced voltage boosting of the Z-source network while simultaneously achieving reduced common-mode switching. Because of the omission of dead-time delays...

  13. Monitoring the Switching of Single BSA-ATTO 488 Molecules Covalently End-Attached to a pH-Responsive PAA Brush

    NARCIS (Netherlands)

    Akkilic, Namik; Molenaar, Robert; Claessens, Mireille Maria Anna Elisabeth; Blum, Christian; de Vos, Wiebe Matthijs

    2016-01-01

    We describe a novel combination of a responsive polymer brush and a fluorescently labeled biomolecule, where the position of the biomolecule can be switched from inside to outside the brush and vice versa by a change in pH. For this, we grafted ultrathin, amino-terminated poly(acrylic acid) brushes

  14. Tutorial: Integrated-photonic switching structures

    Science.gov (United States)

    Soref, Richard

    2018-02-01

    Recent developments in waveguided 2 × 2 and N × M photonic switches are reviewed, including both broadband and narrowband resonant devices for the Si, InP, and AlN platforms. Practical actuation of switches by electro-optical and thermo-optical techniques is discussed. Present datacom-and-computing applications are reviewed, and potential applications are proposed for chip-scale photonic and optoelectronic integrated switching networks. Potential is found in the reconfigurable, programmable "mesh" switches that enable a promising group of applications in new areas beyond those in data centers and cloud servers. Many important matrix switches use gated semiconductor optical amplifiers. The family of broadband, directional-coupler 2 × 2 switches featuring two or three side-coupled waveguides deserves future experimentation, including devices that employ phase-change materials. The newer 2 × 2 resonant switches include standing-wave resonators, different from the micro-ring traveling-wave resonators. The resonant devices comprise nanobeam interferometers, complex-Bragg interferometers, and asymmetric contra-directional couplers. Although the fast, resonant devices offer ultralow switching energy, ˜1 fJ/bit, they have limitations. They require several trade-offs when deployed, but they do have practical application.

  15. Solid spectroscopy: semiconductors

    International Nuclear Information System (INIS)

    Silva, C.E.T.G. da

    1983-01-01

    Photoemission as technique of study of the semiconductor electronic structure is shortly discussed. Homogeneous and heterogeneous semiconductors, where volume and surface electronic structure, core levels and O and H chemisorption in GaAs, Schottky barrier are treated, respectively. Amorphous semiconductors are also discussed. (L.C.) [pt

  16. Intrinsic nanofilamentation in resistive switching

    KAUST Repository

    Wu, Xing

    2013-03-15

    Resistive switching materials are promising candidates for nonvolatile data storage and reconfiguration of electronic applications. Intensive studies have been carried out on sandwiched metal-insulator-metal structures to achieve high density on-chip circuitry and non-volatile memory storage. Here, we provide insight into the mechanisms that govern highly reproducible controlled resistive switching via a nanofilament by using an asymmetric metal-insulator-semiconductor structure. In-situ transmission electron microscopy is used to study in real-time the physical structure and analyze the chemical composition of the nanofilament dynamically during resistive switching. Electrical stressing using an external voltage was applied by a tungsten tip to the nanosized devices having hafnium oxide (HfO2) as the insulator layer. The formation and rupture of the nanofilaments result in up to three orders of magnitude change in the current flowing through the dielectric during the switching event. Oxygen vacancies and metal atoms from the anode constitute the chemistry of the nanofilament.

  17. Strong Exciton-photon Coupling in Semiconductor Microcavities

    DEFF Research Database (Denmark)

    Jensen, Jacob Riis; Borri, Paola; Hvam, Jørn Märcher

    1999-01-01

    The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high directiona......The basic building block of vertical cavity surface emitting lasers (VCSELs) and high efficiency diodes, is a quantum well embedded in a semiconductor microcavity. The high finesse that may be achieved in such a cavity is utilised to get a low threshold current in the VCSELs and a high......-optical switches based on semiconductor microcavities....

  18. Proton-Controlled Organic Microlaser Switch.

    Science.gov (United States)

    Gao, Zhenhua; Zhang, Wei; Yan, Yongli; Yi, Jun; Dong, Haiyun; Wang, Kang; Yao, Jiannian; Zhao, Yong Sheng

    2018-05-25

    Microscale laser switches have been playing irreplaceable roles in the development of photonic devices with high integration levels. However, it remains a challenge to switch the lasing wavelengths across a wide range due to relatively fixed energy bands in traditional semiconductors. Here, we report a strategy to switch the lasing wavelengths among multiple states based on a proton-controlled intramolecular charge-transfer (ICT) process in organic dye-doped flexible microsphere resonant cavities. The protonic acids can effectively bind onto the ICT molecules, which thus enhance the ICT strength of the dyes and lead to a red-shifted gain behavior. On this basis, the gain region was effectively modulated by using acids with different proton-donating ability, and as a result, laser switching among multiple wavelengths was achieved. The results will provide guidance for the rational design of miniaturized lasers with performances based on the characteristic of organic optoelectronic materials.

  19. Diluted magnetic semiconductor nanowires exhibiting magnetoresistance

    Science.gov (United States)

    Yang, Peidong [El Cerrito, CA; Choi, Heonjin [Seoul, KR; Lee, Sangkwon [Daejeon, KR; He, Rongrui [Albany, CA; Zhang, Yanfeng [El Cerrito, CA; Kuykendal, Tevye [Berkeley, CA; Pauzauskie, Peter [Berkeley, CA

    2011-08-23

    A method for is disclosed for fabricating diluted magnetic semiconductor (DMS) nanowires by providing a catalyst-coated substrate and subjecting at least a portion of the substrate to a semiconductor, and dopant via chloride-based vapor transport to synthesize the nanowires. Using this novel chloride-based chemical vapor transport process, single crystalline diluted magnetic semiconductor nanowires Ga.sub.1-xMn.sub.xN (x=0.07) were synthesized. The nanowires, which have diameters of .about.10 nm to 100 nm and lengths of up to tens of micrometers, show ferromagnetism with Curie temperature above room temperature, and magnetoresistance up to 250 Kelvin.

  20. Pseudospark switches (PSS) for pulsed power applications

    Energy Technology Data Exchange (ETDEWEB)

    Heine, F; Prucker, U; Frank, K; Goertler, A; Schwandner, A; Tkotz, R; Hoffmann, D H.H.; Christiansen, J [Univ. of Erlangen (Germany). Physics Dept. I

    1997-12-31

    Based on the pseudospark discharge, a low pressure gas discharge in a special geometry, fast closing switches for different pulsed power applications have been designed. Medium power PSS ({<=} 30 kA peak current) were used in laser circuits whereas high current PSS are tested successfully in high current pulsed power applications ({<=} 200 kA). For currents of a few kA the discharge is supported by cathode spots on the cold cathode surface. For higher currents, anode activity is observed too. Inserting semiconductor material seems not only to suppress high erosive spot formation but to support diffuse large-area electrode emission. A different approach to solving the problem of lowering the erosion rate is the multichannel PSS (MUPS). In order to distribute the discharge current to more than one single channel, three or more discharge channels are radial or coaxial arranged. With regard to high voltage applications the maximum hold-off voltage was increased by adding an intermediate electrode. (author). 1 figs., 12 refs.

  1. Semiconductor Quantum Electron Wave Transport, Diffraction, and Interference: Analysis, Device, and Measurement.

    Science.gov (United States)

    Henderson, Gregory Newell

    Semiconductor device dimensions are rapidly approaching a fundamental limit where drift-diffusion equations and the depletion approximation are no longer valid. In this regime, quantum effects can dominate device response. To increase further device density and speed, new devices must be designed that use these phenomena to positive advantage. In addition, quantum effects provide opportunities for a new class of devices which can perform functions previously unattainable with "conventional" semiconductor devices. This thesis has described research in the analysis of electron wave effects in semiconductors and the development of methods for the design, fabrication, and characterization of quantum devices based on these effects. First, an exact set of quantitative analogies are presented which allow the use of well understood optical design and analysis tools for the development of electron wave semiconductor devices. Motivated by these analogies, methods are presented for modeling electron wave grating diffraction using both an exact rigorous coupled-wave analysis and approximate analyses which are useful for grating design. Example electron wave grating switch and multiplexer designs are presented. In analogy to thin-film optics, the design and analysis of electron wave Fabry-Perot interference filters are also discussed. An innovative technique has been developed for testing these (and other) electron wave structures using Ballistic Electron Emission Microscopy (BEEM). This technique uses a liquid-helium temperature scanning tunneling microscope (STM) to perform spectroscopy of the electron transmittance as a function of electron energy. Experimental results show that BEEM can resolve even weak quantum effects, such as the reflectivity of a single interface between materials. Finally, methods are discussed for incorporating asymmetric electron wave Fabry-Perot filters into optoelectronic devices. Theoretical and experimental results show that such structures could

  2. 重复雷击和操作冲击时单相GIB的金属微粒运动形态%Movement Patterns of Metallic Particles in a Single Phase Gas Insulated Busduct with Superimposed Lightning and Switching Impulses

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Transient over voltages due to lightning and switching surges cause steep build-up of voltage on transmission lines and other electrical apparatus, like circuit breakers, transformers, insulators etc. Therefore it is necessary for the GIS also to withstand such voltages without breakdown of Insulation . The system has to be tested under these conditions. Usually the GIS system operates on power frequency. Lightning Impulse Voltage of 1050 kV and Switching Impulse Voltage of 750 kV superimposed on Power frequency voltages of 75 kV, 100 kV and 132 kV are applied to Single Phase Gas Insulated Busduct and the maximum movement of Aluminum, Copper and Silver particles is determined. The movement patterns are also determined with and without Monte Carlo Simulation for movement of particle in axial and radial directions. The results show that there is a sudden jump in the movement at the application of impulse on sine wave. This is because of high magnitude voltage of 1050 kV during 1.2/50 μs. Similar movement patterns of reduced maximum movement is observed for Switching Impulse superimposed on sine wave. The results are presented and analyzed.

  3. NMR and NQR study of Si-doped (6,0) zigzag single-walled aluminum nitride nanotube as n or P-semiconductors.

    Science.gov (United States)

    Baei, Mohammad T; Peyghan, Ali Ahmadi; Tavakoli, Khadijeh; Babaheydari, Ali Kazemi; Moghimi, Masoumeh

    2012-09-01

    Density functional theory (DFT) calculations were performed to investigate the electronic structure properties of pristine and Si-doped aluminum nitride nanotubes as n or P-semiconductors at the B3LYP/6-31G* level of theory in order to evaluate the influence of Si-doped in the (6,0) zigzag AlNNTs. We extended the DFT calculation to predict the electronic structure properties of Si-doped aluminum nitride nanotubes, which are very important for production of solid-state devices and other applications. To this aim, pristine and Si-doped AlNNT structures in two models (Si(N) and Si(Al)) were optimized, and then the electronic properties, the isotropic (CS(I)) and anisotropic (CS(A)) chemical shielding parameters for the sites of various (27)Al and (14)N atoms, NQR parameters for the sites of various of (27)Al and (14)N atoms, and quantum molecular descriptors were calculated in the optimized structures. The optimized structures, the electronic properties, NMR and NQR parameters, and quantum molecular descriptors for the Si(N) and Si(Al) models show that the Si(N) model is a more reactive material than the pristine or Si(Al) model.

  4. Tunable Broadband Acoustic Gain in Piezoelectric Semiconductors at ε-Near-Zero Response

    DEFF Research Database (Denmark)

    Christensen, Johan; Willatzen, Morten

    2015-01-01

    Piezoelectric semiconductors have emerged as materials capable to amplify sound waves when electrons are set to drift at supersonic speeds. Several experiments have demonstrated this behaviour at moderate amplification levels for some intrinsic semiconductors and carrier concentrations......-compensation in metamaterials and applicable for sensing such as nonlinear devices. The paper contains a detailed derivation and discussion of transmission and reflection coefficients for pressure pulses impinging on a semiconductor slab and the acoustic gain enhancement that can be achieved by dynamic switching...

  5. Switch to Rilpivirine/Emtricitabine/Tenofovir Single-Tablet Regimen of Human Immunodeficiency Virus-1 RNA-Suppressed Patients, Agence Nationale de Recherches sur le SIDA et les Hépatites Virales CO3 Aquitaine Cohort, 2012-2014.

    Science.gov (United States)

    Cazanave, Charles; Reigadas, Sandrine; Mazubert, Cyril; Bellecave, Pantxika; Hessamfar, Mojgan; Le Marec, Fabien; Lazaro, Estibaliz; Peytavin, Gilles; Bruyand, Mathias; Fleury, Hervé; Dabis, François; Neau, Didier

    2015-01-01

    Background.  The purpose of this study was to assess the efficacy and tolerability of combined antiretroviral therapy (cART) in human immunodeficiency virus (HIV)-1 virologically suppressed patients who switched to rilpivirine (RPV)/tenofovir disoproxil fumarate (TDF)/emtricitabine (FTC) as a single-tablet regimen (STR). Methods.  A retrospective multicenter cohort study was performed between September 2012 and February 2014 in Bordeaux University Hospital-affiliated clinics. Patients with a plasma HIV viral load (VL) lower than 50 copies/mL and switching to STR were evaluated at baseline, 3, 6, 9, and 12 months from switch time (M3, M6, M9, M12) for VL and other biological parameters. Change from baseline in CD4 cell counts was evaluated at M6 and M12. Virological failure (VF) was defined as 2 consecutive VL >50 copies/mL. Results.  Three hundred four patients were included in the analysis. Single-tablet regimen switch was proposed to 116 patients with adverse events, mostly efavirenz (EFV)-based (n = 59), and to 224 patients for cART simplification. Thirty of 196 patients with available genotype resistance test results displayed virus with ≥1 drug resistance mutation on reverse-transcriptase gene. After 12 months of follow-up, 93.4% (95.5% confidence interval, 89.9-96.2) of patients remained virologically suppressed. There was no significant change in CD4 cell count. During the study period, 5 patients experienced VF, one of them harboring RPV resistance mutation. Clinical cART tolerability improved in 79 patients overall (29.9%) at M6, especially neurological symptoms related to EFV. Fasting serum lipid profiles improved, but a significant estimated glomerular function rate decrease (-11 mL/min/1.73 m(2); P < 10(-4)) was observed. Conclusions.  Overall, virologic suppression was maintained in patients after switching to RPV/TDF/ FTC. This STR strategy was associated with improved tolerability.

  6. Switching Phenomena in a System with No Switches

    Science.gov (United States)

    Preis, Tobias; Stanley, H. Eugene

    2010-02-01

    It is widely believed that switching phenomena require switches, but this is actually not true. For an intriguing variety of switching phenomena in nature, the underlying complex system abruptly changes from one state to another in a highly discontinuous fashion. For example, financial market fluctuations are characterized by many abrupt switchings creating increasing trends ("bubble formation") and decreasing trends ("financial collapse"). Such switching occurs on time scales ranging from macroscopic bubbles persisting for hundreds of days to microscopic bubbles persisting only for a few seconds. We analyze a database containing 13,991,275 German DAX Future transactions recorded with a time resolution of 10 msec. For comparison, a database providing 2,592,531 of all S&P500 daily closing prices is used. We ask whether these ubiquitous switching phenomena have quantifiable features independent of the time horizon studied. We find striking scale-free behavior of the volatility after each switching occurs. We interpret our findings as being consistent with time-dependent collective behavior of financial market participants. We test the possible universality of our result by performing a parallel analysis of fluctuations in transaction volume and time intervals between trades. We show that these financial market switching processes have properties similar to those of phase transitions. We suggest that the well-known catastrophic bubbles that occur on large time scales—such as the most recent financial crisis—are no outliers but single dramatic representatives caused by the switching between upward and downward trends on time scales varying over nine orders of magnitude from very large (≈102 days) down to very small (≈10 ms).

  7. Pinning Synchronization of Switched Complex Dynamical Networks

    Directory of Open Access Journals (Sweden)

    Liming Du

    2015-01-01

    Full Text Available Network topology and node dynamics play a key role in forming synchronization of complex networks. Unfortunately there is no effective synchronization criterion for pinning synchronization of complex dynamical networks with switching topology. In this paper, pinning synchronization of complex dynamical networks with switching topology is studied. Two basic problems are considered: one is pinning synchronization of switched complex networks under arbitrary switching; the other is pinning synchronization of switched complex networks by design of switching when synchronization cannot achieved by using any individual connection topology alone. For the two problems, common Lyapunov function method and single Lyapunov function method are used respectively, some global synchronization criteria are proposed and the designed switching law is given. Finally, simulation results verify the validity of the results.

  8. Single crystalline growth of a soluble organic semiconductor in a parallel aligned liquid crystal solvent using rubbing-treated polyimide films

    Science.gov (United States)

    Matsuzaki, Tomoya; Shibata, Yosei; Takeda, Risa; Ishinabe, Takahiro; Fujikake, Hideo

    2017-01-01

    For directional control of organic single crystals, we propose a crystal growth method using liquid crystal as the solvent. In this study, we examined the formation of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) single crystals using a parallel aligned liquid crystal (LC) cell and rubbing-treated polyimide films in order to clarify the effects of LC alignment on anisotropic C8-BTBT crystal growth. Based on the results, we found that the crystal growth direction of C8-BTBT single crystals was related to the direction of the aligned LC molecules because of rubbing treatment. Moreover, by optical evaluation, we found that the C8-BTBT single crystals have a aligned molecular structure.

  9. Optimization of multi-branch switched diversity systems

    KAUST Repository

    Nam, Haewoon

    2009-10-01

    A performance optimization based on the optimal switching threshold(s) for a multi-branch switched diversity system is discussed in this paper. For the conventional multi-branch switched diversity system with a single switching threshold, the optimal switching threshold is a function of both the average channel SNR and the number of diversity branches, where computing the optimal switching threshold is not a simple task when the number of diversity branches is high. The newly proposed multi-branch switched diversity system is based on a sequence of switching thresholds, instead of a single switching threshold, where a different diversity branch uses a different switching threshold for signal comparison. Thanks to the fact that each switching threshold in the sequence can be optimized only based on the number of the remaining diversity branches, the proposed system makes it easy to find these switching thresholds. Furthermore, some selected numerical and simulation results show that the proposed switched diversity system with the sequence of optimal switching thresholds outperforms the conventional system with the single optimal switching threshold. © 2009 IEEE.

  10. Bistable four-wave mixing response in a semiconductor quantum dot coupled to a photonic crystal nanocavity.

    Science.gov (United States)

    Li, Jian-Bo; Xiao, Si; Liang, Shan; He, Meng-Dong; Luo, Jian-Hua; Kim, Nam-Chol; Chen, Li-Qun

    2017-10-16

    We perform a theoretical study of the bistable four-wave mixing (FWM) response in a coupled system comprised of a semiconductor quantum dot (SQD) and a photonic crystal (PC) nanocavity in which the SQD is embedded. It is shown that the shape of the FWM spectrum can switch among single-peaked, double-peaked, triple-peaked, and four-peaked arising from the vacuum Rabi splitting and the exciton-nanocavity coupling. Especially, we map out bistability phase diagrams within a parameter subspace of the system, and find that it is easy to turn on or off the bistable FWM response by only adjusting the excitation frequency or the pumping intensity. Our results offer a feasible means for measuring the SQD-PC nanocavity coupling strength and open a new avenue to design optical switches and memories.

  11. Compound Semiconductor Radiation Detector

    International Nuclear Information System (INIS)

    Kim, Y. K.; Park, S. H.; Lee, W. G.; Ha, J. H.

    2005-01-01

    In 1945, Van Heerden measured α, β and γ radiations with the cooled AgCl crystal. It was the first radiation measurement using the compound semiconductor detector. Since then the compound semiconductor has been extensively studied as radiation detector. Generally the radiation detector can be divided into the gas detector, the scintillator and the semiconductor detector. The semiconductor detector has good points comparing to other radiation detectors. Since the density of the semiconductor detector is higher than that of the gas detector, the semiconductor detector can be made with the compact size to measure the high energy radiation. In the scintillator, the radiation is measured with the two-step process. That is, the radiation is converted into the photons, which are changed into electrons by a photo-detector, inside the scintillator. However in the semiconductor radiation detector, the radiation is measured only with the one-step process. The electron-hole pairs are generated from the radiation interaction inside the semiconductor detector, and these electrons and charged ions are directly collected to get the signal. The energy resolution of the semiconductor detector is generally better than that of the scintillator. At present, the commonly used semiconductors as the radiation detector are Si and Ge. However, these semiconductor detectors have weak points. That is, one needs thick material to measure the high energy radiation because of the relatively low atomic number of the composite material. In Ge case, the dark current of the detector is large at room temperature because of the small band-gap energy. Recently the compound semiconductor detectors have been extensively studied to overcome these problems. In this paper, we will briefly summarize the recent research topics about the compound semiconductor detector. We will introduce the research activities of our group, too

  12. Semiconductor apparatus and method of fabrication for a semiconductor apparatus

    NARCIS (Netherlands)

    2010-01-01

    The invention relates to a semiconductor apparatus (1) and a method of fabrication for a semiconductor apparatus (1), wherein the semiconductor apparatus (1) comprises a semiconductor layer (2) and a passivation layer (3), arranged on a surface of the semiconductor layer (2), for passivating the

  13. Designing field-controllable graphene-dot-graphene single molecule switches: A quantum-theoretical proof-of-concept under realistic operating conditions.

    Science.gov (United States)

    Pejov, Ljupčo; Petreska, Irina; Kocarev, Ljupčo

    2015-12-28

    A theoretical proof of the concept that a particularly designed graphene-based moletronics device, constituted by two semi-infinite graphene subunits, acting as source and drain electrodes, and a central benzenoid ring rotator (a "quantum dot"), could act as a field-controllable molecular switch is outlined and analyzed with the density functional theory approach. Besides the ideal (0 K) case, we also consider the operation of such a device under realistic operating (i.e., finite-temperature) conditions. An in-depth insight into the physics behind device controllability by an external field was gained by thorough analyses of the torsional potential of the dot under various conditions (absence or presence of an external gating field with varying strength), computing the torsional correlation time and transition probabilities within the Bloembergen-Purcell-Pound formalism. Both classical and quantum mechanical tunneling contributions to the intramolecular rotation were considered in the model. The main idea that we put forward in the present study is that intramolecular rotors can be controlled by the gating field even in cases when these groups do not possess a permanent dipole moment (as in cases considered previously by us [I. Petreska et al., J. Chem. Phys. 134, 014708-1-014708-12 (2011)] and also by other groups [P. E. Kornilovitch et al., Phys. Rev. B 66, 245413-1-245413-7 (2002)]). Consequently, one can control the molecular switching properties by an external electrostatic field utilizing even nonpolar intramolecular rotors (i.e., in a more general case than those considered so far). Molecular admittance of the currently considered graphene-based molecular switch under various conditions is analyzed employing non-equilibrium Green's function formalism, as well as by analysis of frontier molecular orbitals' behavior.

  14. A soft switching with reduced voltage stress ZVT-PWM full-bridge converter

    Science.gov (United States)

    Sahin, Yakup; Ting, Naim Suleyman; Acar, Fatih

    2018-04-01

    This paper introduces a novel active snubber cell for soft switching pulse width modulation DC-DC converters. In the proposed converter, the main switch is turned on under zero voltage transition and turned off under zero voltage switching (ZVS). The auxiliary switch is turned on under zero current switching (ZCS) and turned off under zero current transition. The main diode is turned on under ZVS and turned off under ZCS. All of the other semiconductors in the converter are turned on and off with soft switching. There is no extra voltage stress on the semiconductor devices. Besides, the proposed converter has simple structure and ease of control due to common ground. The detailed theoretical analysis of the proposed converter is presented and also verified with both simulation and experimental study at 100 kHz switching frequency and 600 W output power. Furthermore, the efficiency of the proposed converter is 95.7% at nominal power.

  15. Transient photoconductivity in amorphous semiconductors

    International Nuclear Information System (INIS)

    Mpawenayo, P.

    1997-07-01

    Localized states in amorphous semiconductors are divided in disorder induced shallow trap levels and dangling bonds deep states. Dangling bonds are assumed here to be either neutral or charged and their energy distribution is a single gaussian. Here, it is shown analytically that transient photocurrent in amorphous semiconductors is fully controlled by charge carriers transitions between localized states for one part and tunneling hopping carriers on the other. Localized dangling bonds deep states act as non radiative recombination centres, while hopping tunnelling is assisted by the Coulomb interaction between defects sites. The half-width of defects distribution is the disorder parameter that determines the carrier hopping time between defects sites. The macroscopic time that explains the long decay response times observed will all types of amorphous semiconductors is duly thought to be temperature dependent. Basic equations developed by Longeaud and Kleider are solved for the general case of a semiconductor after photo-generation. It turns out that the transient photoconductivity decay has two components; one with short response times from carriers trap-release transitions between shallow levels and extended states and a hopping component made of inter-dependent exponentials whose time constants span in larger ranges depending on disorder. The photoconductivity hopping component appears as an additional term to be added to photocurrents derived from existing models. The results of the present study explain and complete the power law decay derived in the multiple trapping models developed 20 years ago only in the approximation of the short response time regime. The long response time regime is described by the hopping macroscopic time. The present model is verified for all samples of amorphous semiconductors known so far. Finally, it is proposed to improved the modulated photoconductivity calculation techniques by including the long-lasting hopping dark documents

  16. Schottky nanocontact of one-dimensional semiconductor nanostructures probed by using conductive atomic force microscopy

    Science.gov (United States)

    Lee, Jung Ah; Rok Lim, Young; Jung, Chan Su; Choi, Jun Hee; Im, Hyung Soon; Park, Kidong; Park, Jeunghee; Kim, Gyu Tae

    2016-10-01

    To develop the advanced electronic devices, the surface/interface of each component must be carefully considered. Here, we investigate the electrical properties of metal-semiconductor nanoscale junction using conductive atomic force microscopy (C-AFM). Single-crystalline CdS, CdSe, and ZnO one-dimensional nanostructures are synthesized via chemical vapor transport, and individual nanobelts (or nanowires) are used to fabricate nanojunction electrodes. The current-voltage (I -V) curves are obtained by placing a C-AFM metal (PtIr) tip as a movable contact on the nanobelt (or nanowire), and often exhibit a resistive switching behavior that is rationalized by the Schottky (high resistance state) and ohmic (low resistance state) contacts between the metal and semiconductor. We obtain the Schottky barrier height and the ideality factor through fitting analysis of the I-V curves. The present nanojunction devices exhibit a lower Schottky barrier height and a higher ideality factor than those of the bulk materials, which is consistent with the findings of previous works on nanostructures. It is shown that C-AFM is a powerful tool for characterization of the Schottky contact of conducting channels between semiconductor nanostructures and metal electrodes.

  17. A 4 × 2 switch matrix in QFN24 package for 0.5–3 GHz application

    International Nuclear Information System (INIS)

    Liu Yuzhe; Mu Pengfei; Gong Renjie; Wan Jing; Zhang Yulin; Yan Yuepeng

    2014-01-01

    This paper presents a 4 × 2 switching matrix implemented in the Win 0.5 μm GaAs pseudomorphic high electron mobility transistor process, it covers the 0.5–3 GHz frequency range. The switch matrix is composed of 4 SPDT switch whose two output ports can simultaneously select the input port and a 4 to 8 bit digital decoder, both the radio frequency (RF) part and the digital part are integrated into one single chip. The chip is packaged in a low cost QFN24 plastic package. On chip shunt, capacitors at the input ports are taken to compensate for the bonding wire inductance effect. The designed switch matrix shows a good measured performance: the insertion loss is less than 5.5 dB, the isolation is no worse than 30 dB, the return loss of input ports and output ports is better than −10 dB, the input 1 dB compression point is better than 25.6 dBm, and the OIP3 is better than 37 dBm. The chip size of the switch matrix is only 1.45 × 1.45 mm 2 . (semiconductor integrated circuits)

  18. Semiconductor Physical Electronics

    CERN Document Server

    Li, Sheng

    2006-01-01

    Semiconductor Physical Electronics, Second Edition, provides comprehensive coverage of fundamental semiconductor physics that is essential to an understanding of the physical and operational principles of a wide variety of semiconductor electronic and optoelectronic devices. This text presents a unified and balanced treatment of the physics, characterization, and applications of semiconductor materials and devices for physicists and material scientists who need further exposure to semiconductor and photonic devices, and for device engineers who need additional background on the underlying physical principles. This updated and revised second edition reflects advances in semicondutor technologies over the past decade, including many new semiconductor devices that have emerged and entered into the marketplace. It is suitable for graduate students in electrical engineering, materials science, physics, and chemical engineering, and as a general reference for processing and device engineers working in the semicondi...

  19. Charge regulation at semiconductor-electrolyte interfaces.

    Science.gov (United States)

    Fleharty, Mark E; van Swol, Frank; Petsev, Dimiter N

    2015-07-01

    The interface between a semiconductor material and an electrolyte solution has interesting and complex electrostatic properties. Its behavior will depend on the density of mobile charge carriers that are present in both phases as well as on the surface chemistry at the interface through local charge regulation. The latter is driven by chemical equilibria involving the immobile surface groups and the potential determining ions in the electrolyte solution. All these lead to an electrostatic potential distribution that propagate such that the electrolyte and the semiconductor are dependent on each other. Hence, any variation in the charge density in one phase will lead to a response in the other. This has significant implications on the physical properties of single semiconductor-electrolyte interfaces and on the electrostatic interactions between semiconductor particles suspended in electrolyte solutions. The present paper expands on our previous publication (Fleharty et al., 2014) and offers new results on the electrostatics of single semiconductor interfaces as well as on the interaction of charged semiconductor colloids suspended in electrolyte solution. Copyright © 2014 Elsevier Inc. All rights reserved.

  20. Analysis and simulation of semiconductor devices

    CERN Document Server

    Selberherr, Siegfried

    1984-01-01

    The invention of semiconductor devices is a fairly recent one, considering classical time scales in human life. The bipolar transistor was announced in 1947, and the MOS transistor, in a practically usable manner, was demonstrated in 1960. From these beginnings the semiconductor device field has grown rapidly. The first integrated circuits, which contained just a few devices, became commercially available in the early 1960s. Immediately thereafter an evolution has taken place so that today, less than 25 years later, the manufacture of integrated circuits with over 400.000 devices per single chip is possible. Coincident with the growth in semiconductor device development, the literature concerning semiconductor device and technology issues has literally exploded. In the last decade about 50.000 papers have been published on these subjects. The advent of so called Very-Large-Scale-Integration (VLSI) has certainly revealed the need for a better understanding of basic device behavior. The miniaturization of the s...

  1. Semiconductor electrolyte photovoltaic energy converter

    Science.gov (United States)

    Anderson, W. W.; Anderson, L. B.

    1975-01-01

    Feasibility and practicality of a solar cell consisting of a semiconductor surface in contact with an electrolyte are evaluated. Basic components and processes are detailed for photovoltaic energy conversion at the surface of an n-type semiconductor in contact with an electrolyte which is oxidizing to conduction band electrons. Characteristics of single crystal CdS, GaAs, CdSe, CdTe and thin film CdS in contact with aqueous and methanol based electrolytes are studied and open circuit voltages are measured from Mott-Schottky plots and open circuit photo voltages. Quantum efficiencies for short circuit photo currents of a CdS crystal and a 20 micrometer film are shown together with electrical and photovoltaic properties. Highest photon irradiances are observed with the GaAs cell.

  2. Contacts to semiconductors

    International Nuclear Information System (INIS)

    Tove, P.A.

    1975-08-01

    Contacts to semiconductors play an important role in most semiconductor devices. These devices range from microelectronics to power components, from high-sensitivity light or radiation detectors to light-emitting of microwave-generating components. Silicon is the dominating material but compound semiconductors are increasing in importance. The following survey is an attempt to classify contact properties and the physical mechanisms involved, as well as fabrication methods and methods of investigation. The main interest is in metal-semiconductor type contacts where a few basic concepts are dealt with in some detail. (Auth.)

  3. Semiconductor Electrical Measurements Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The Semiconductor Electrical Measurements Laboratory is a research laboratory which complements the Optical Measurements Laboratory. The laboratory provides for Hall...

  4. Switched on!

    CERN Multimedia

    2008-01-01

    Like a star arriving on stage, impatiently followed by each member of CERN personnel and by millions of eyes around the world, the first beam of protons has circulated in the LHC. After years in the making and months of increasing anticipation, today the work of hundreds of people has borne fruit. WELL DONE to all! Successfully steered around the 27 kilometres of the world’s most powerful particle accelerator at 10:28 this morning, this first beam of protons circulating in the ring marks a key moment in the transition from over two decades of preparation to a new era of scientific discovery. "It’s a fantastic moment," said the LHC project leader Lyn Evans, "we can now look forward to a new era of understanding about the origins and evolution of the universe". Starting up a major new particle accelerator takes much more than flipping a switch. Thousands of individual elements have to work in harmony, timings have to be synchronize...

  5. A dark-field microscope for background-free detection of resonance fluorescence from single semiconductor quantum dots operating in a set-and-forget mode.

    Science.gov (United States)

    Kuhlmann, Andreas V; Houel, Julien; Brunner, Daniel; Ludwig, Arne; Reuter, Dirk; Wieck, Andreas D; Warburton, Richard J

    2013-07-01

    Optically active quantum dots, for instance self-assembled InGaAs quantum dots, are potentially excellent single photon sources. The fidelity of the single photons is much improved using resonant rather than non-resonant excitation. With resonant excitation, the challenge is to distinguish between resonance fluorescence and scattered laser light. We have met this challenge by creating a polarization-based dark-field microscope to measure the resonance fluorescence from a single quantum dot at low temperature. We achieve a suppression of the scattered laser exceeding a factor of 10(7) and background-free detection of resonance fluorescence. The same optical setup operates over the entire quantum dot emission range (920-980 nm) and also in high magnetic fields. The major development is the outstanding long-term stability: once the dark-field point has been established, the microscope operates for days without alignment. The mechanical and optical designs of the microscope are presented, as well as exemplary resonance fluorescence spectroscopy results on individual quantum dots to underline the microscope's excellent performance.

  6. A dark-field microscope for background-free detection of resonance fluorescence from single semiconductor quantum dots operating in a set-and-forget mode

    International Nuclear Information System (INIS)

    Kuhlmann, Andreas V.; Houel, Julien; Warburton, Richard J.; Brunner, Daniel; Ludwig, Arne; Reuter, Dirk; Wieck, Andreas D.

    2013-01-01

    Optically active quantum dots, for instance self-assembled InGaAs quantum dots, are potentially excellent single photon sources. The fidelity of the single photons is much improved using resonant rather than non-resonant excitation. With resonant excitation, the challenge is to distinguish between resonance fluorescence and scattered laser light. We have met this challenge by creating a polarization-based dark-field microscope to measure the resonance fluorescence from a single quantum dot at low temperature. We achieve a suppression of the scattered laser exceeding a factor of 10 7 and background-free detection of resonance fluorescence. The same optical setup operates over the entire quantum dot emission range (920–980 nm) and also in high magnetic fields. The major development is the outstanding long-term stability: once the dark-field point has been established, the microscope operates for days without alignment. The mechanical and optical designs of the microscope are presented, as well as exemplary resonance fluorescence spectroscopy results on individual quantum dots to underline the microscope's excellent performance

  7. Effect of gain nonlinearity in semiconductor lasers

    DEFF Research Database (Denmark)

    Jensen, Niels H.; Christiansen, Peter Leth; Skovgaard, Ove

    1988-01-01

    Semiconductor lasers are modeled by single-mode rate equations with Langevin noise terms and the influence of nonlinear gain is investigated. For cw operation the probability distribution for the carrier number and the photon number in the laser cavity is obtained. The corresponding (2+1)-dimensi......Semiconductor lasers are modeled by single-mode rate equations with Langevin noise terms and the influence of nonlinear gain is investigated. For cw operation the probability distribution for the carrier number and the photon number in the laser cavity is obtained. The corresponding (2...

  8. Enhancement of resistive switching properties in Al2O3 bilayer-based atomic switches: multilevel resistive switching

    Science.gov (United States)

    Vishwanath, Sujaya Kumar; Woo, Hyunsuk; Jeon, Sanghun

    2018-06-01

    Atomic switches are considered to be building blocks for future non-volatile data storage and internet of things. However, obtaining device structures capable of ultrahigh density data storage, high endurance, and long data retention, and more importantly, understanding the switching mechanisms are still a challenge for atomic switches. Here, we achieved improved resistive switching performance in a bilayer structure containing aluminum oxide, with an oxygen-deficient oxide as the top switching layer and stoichiometric oxide as the bottom switching layer, using atomic layer deposition. This bilayer device showed a high on/off ratio (105) with better endurance (∼2000 cycles) and longer data retention (104 s) than single-oxide layers. In addition, depending on the compliance current, the bilayer device could be operated in four different resistance states. Furthermore, the depth profiles of the hourglass-shaped conductive filament of the bilayer device was observed by conductive atomic force microscopy.

  9. Carrier concentration induced ferromagnetism in semiconductors

    International Nuclear Information System (INIS)

    Story, T.

    2007-01-01

    In semiconductor spintronics the key materials issue concerns ferromagnetic semiconductors that would, in particular, permit an integration (in a single multilayer heterostructure) of standard electronic functions of semiconductors with magnetic memory function. Although classical semiconductor materials, such as Si or GaAs, are nonmagnetic, upon substitutional incorporation of magnetic ions (typically of a few atomic percents of Mn 2+ ions) and very heavy doping with conducting carriers (at the level of 10 20 - 10 21 cm -3 ) a ferromagnetic transition can be induced in such diluted magnetic semiconductors (also known as semimagnetic semiconductors). In the lecture the spectacular experimental observations of carrier concentration induced ferromagnetism will be discussed for three model semiconductor crystals. p - Ga 1-x Mn x As currently the most actively studied and most perspective ferromagnetic semiconductor of III-V group, in which ferromagnetism appears due to Mn ions providing both local magnetic moments and acting as acceptor centers. p - Sn 1-x Mn x Te and p - Ge 1-x Mn x Te classical diluted magnetic semiconductors of IV-VI group, in which paramagnet-ferromagnet and ferromagnet-spin glass transitions are found for very high hole concentration. n - Eu 1-x Gd x Te mixed magnetic crystals, in which the substitution of Gd 3+ ions for Eu 2+ ions creates very high electron concentration and transforms antiferromagnetic EuTe (insulating compound) into ferromagnetic n-type semiconductor alloy. For each of these materials systems the key physical features will be discussed concerning: local magnetic moments formation, magnetic phase diagram as a function of magnetic ions and carrier concentration as well as Curie temperature and magnetic anisotropy engineering. Various theoretical models proposed to explain the effect of carrier concentration induced ferromagnetism in semiconductors will be briefly discussed involving mean field approaches based on Zener and RKKY

  10. The supply voltage scaled dependency of the recovery of single event upset in advanced complementary metal—oxide—semiconductor static random-access memory cells

    International Nuclear Information System (INIS)

    Li Da-Wei; Qin Jun-Rui; Chen Shu-Ming

    2013-01-01

    Using computer-aided design three-dimensional simulation technology, the supply voltage scaled dependency of the recovery of single event upset and charge collection in static random-access memory cells are investigated. It reveals that the recovery linear energy transfer threshold decreases with the supply voltage reducing, which is quite attractive for dynamic voltage scaling and subthreshold circuit radiation-hardened design. Additionally, the effect of supply voltage on charge collection is also investigated. It is concluded that the supply voltage mainly affects the bipolar gain of the parasitical bipolar junction transistor (BJT) and the existence of the source plays an important role in supply voltage variation. (geophysics, astronomy, and astrophysics)

  11. Microwave pulse generation by photoconductive switching

    Energy Technology Data Exchange (ETDEWEB)

    Pocha, M.D.; Druce, R.L.

    1989-03-14

    Laser activated photoconductive semiconductor switching shows significant potential for application in high power microwave generation. Primary advantages of this concept are: small size, light weight, ruggedness, precise timing and phasing by optical control, and the potential for high peak power in short pulses. Several concepts have been suggested for microwave generation using this technology. They generally fall into two categories (1) the frozen wave generator or (2) tuned cavity modulation, both of which require only fast closing switches. We have been exploring a third possibility requiring fast closing and opening switches, that is the direct modulation of the switch at microwave frequencies. Switches have been fabricated at LLNL using neutron irradiated Gallium Arsenide which exhibit response times as short as 50 ps at low voltages. We are in the process of performing high voltage tests. So far, we have been able to generate 2.4 kV pulses with approximately 340 ps response time (FWHM) using approximately a 200..mu..J optical pulse. Experiments are continuing to increase the voltage and improve the switching efficiency. 3 refs., 6 figs.

  12. Microwave pulse generation by photoconductive switching

    Science.gov (United States)

    Pocha, M. D.; Druce, R. L.

    1989-03-01

    Laser activated photoconductive semiconductor switching shows significant potential for application in high power microwave generation. Primary advantages of this concept are: small size, light weight, ruggedness, precise timing and phasing by optical control, and the potential for high peak power in short pulses. Several concepts have been suggested for microwave generation using this technology. They generally fall into two categories: (1) the frozen wave generator, or (2) tuned cavity modulation, both of which require only fast closing switches. We have been exploring a third possibility requiring fast closing and opening switches, that is the direct modulation of the switch at microwave frequencies. Switches have been fabricated at LLNL using neutron irradiated Gallium Arsenide which exhibit response times as short as 50 ps at low voltages. We are in the process of performing high voltage tests. So far, we have been able to generate 2.4 kV pulses with approximately 340 ps response time (FWHM) using approximately a 200 microJ optical pulse. Experiments are continuing to increase the voltage and improve the switching efficiency.

  13. Semiconductors data handbook

    CERN Document Server

    Madelung, Otfried

    2004-01-01

    This volume Semiconductors: Data Handbook contains frequently used data from the corresponding larger Landolt-Börnstein handbooks in a low price book for the individual scientist working in the laboratory. The Handbook contain important information about a large number of semiconductors

  14. Semiconductor radiation detection systems

    CERN Document Server

    2010-01-01

    Covers research in semiconductor detector and integrated circuit design in the context of medical imaging using ionizing radiation. This book explores other applications of semiconductor radiation detection systems in security applications such as luggage scanning, dirty bomb detection and border control.

  15. Spin physics in semiconductors

    CERN Document Server

    Dyakonov, Mikhail I

    2008-01-01

    This book describes beautiful optical and transport phenomena related to the electron and nuclear spins in semiconductors with emphasis on a clear presentation of the physics involved. Recent results on quantum wells and quantum dots are reviewed. The book is intended for students and researchers in the fields of semiconductor physics and nanoelectronics.

  16. Digital switched hydraulics

    Science.gov (United States)

    Pan, Min; Plummer, Andrew

    2018-06-01

    This paper reviews recent developments in digital switched hydraulics particularly the switched inertance hydraulic systems (SIHSs). The performance of SIHSs is presented in brief with a discussion of several possible configurations and control strategies. The soft switching technology and high-speed switching valve design techniques are discussed. Challenges and recommendations are given based on the current research achievements.

  17. Compound Semiconductor Radiation Detectors

    CERN Document Server

    Owens, Alan

    2012-01-01

    Although elemental semiconductors such as silicon and germanium are standard for energy dispersive spectroscopy in the laboratory, their use for an increasing range of applications is becoming marginalized by their physical limitations, namely the need for ancillary cooling, their modest stopping powers, and radiation intolerance. Compound semiconductors, on the other hand, encompass such a wide range of physical and electronic properties that they have become viable competitors in a number of applications. Compound Semiconductor Radiation Detectors is a consolidated source of information on all aspects of the use of compound semiconductors for radiation detection and measurement. Serious Competitors to Germanium and Silicon Radiation Detectors Wide-gap compound semiconductors offer the ability to operate in a range of hostile thermal and radiation environments while still maintaining sub-keV spectral resolution at X-ray wavelengths. Narrow-gap materials offer the potential of exceeding the spectral resolutio...

  18. Use of radioactive tracers in the semiconductor industry

    International Nuclear Information System (INIS)

    Akerman, Karol

    1975-01-01

    Manufacture of the semiconductor materials comprises production and purification of the raw materials (GeC14 or SiHC13), purification of the elemental semiconductors by metallurgical methods (including zone melting), production and doping of single crystals, dividing the crystals into slices of suitable size, formation of p-n junctions and fabrication of the finished semiconductor devices. In the sequence of operations, the behavior of very small quantities of an element must be monitored, and radioactive tracers are often used to solve these problems. Examples are given of the use of radioactive tracers in the semiconductor industry

  19. Switching Characteristics and High-Temperature Dielectric Relaxation Behaviours of Pb(Zn1/3Nb2/3)0.91Ti0.09O₃ Single Crystal.

    Science.gov (United States)

    Zhu, Zhi; Tang, Xingui; Jiang, Yanping; Liu, Qiuxiang; Zhang, Tianfu; Li, Wenhua

    2017-03-28

    This work evaluated the resistance switching characteristics in the (100)-oriented Pb(Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 O₃ (PZNT) single crystal. The current hysteresis can be closely related to the ferroelectric polarization and we provided a possible explanation using a model about oxygen vacancies to analyze the mechanism of switching. The obvious frequency dispersion of the relative permittivity signified the relaxer-type behavior of the sample. The value of the relaxation parameter γ = 1.48 was estimated from the linear fit of the modified Curie-Weiss law, indicating the relaxer nature. High-temperature dielectric relaxation behaviors were revealed in the temperature region of 400-650 °C. In addition, under the measuring frequency of 10 kHz, ε r was tunable by changing the electric field and the largest tunability of ε r reached 14.78%. At room temperature, the high pyroelectric coefficient and detectivity figure of merit were reported.

  20. Ballistic superconductivity in semiconductor nanowires

    Science.gov (United States)

    Zhang, Hao; Gül, Önder; Conesa-Boj, Sonia; Nowak, Michał P.; Wimmer, Michael; Zuo, Kun; Mourik, Vincent; de Vries, Folkert K.; van Veen, Jasper; de Moor, Michiel W. A.; Bommer, Jouri D. S.; van Woerkom, David J.; Car, Diana; Plissard, Sébastien R; Bakkers, Erik P.A.M.; Quintero-Pérez, Marina; Cassidy, Maja C.; Koelling, Sebastian; Goswami, Srijit; Watanabe, Kenji; Taniguchi, Takashi; Kouwenhoven, Leo P.

    2017-01-01

    Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They have offered an exceptional testbed for superconductivity, leading to the realization of hybrid systems combining the macroscopic quantum properties of superconductors with the possibility to control charges down to a single electron. These advances brought semiconductor nanowires to the forefront of efforts to realize topological superconductivity and Majorana modes. A prime challenge to benefit from the topological properties of Majoranas is to reduce the disorder in hybrid nanowire devices. Here we show ballistic superconductivity in InSb semiconductor nanowires. Our structural and chemical analyses demonstrate a high-quality interface between the nanowire and a NbTiN superconductor that enables ballistic transport. This is manifested by a quantized conductance for normal carriers, a strongly enhanced conductance for Andreev-reflecting carriers, and an induced hard gap with a significantly reduced density of states. These results pave the way for disorder-free Majorana devices. PMID:28681843

  1. A semiconductor laser device

    Energy Technology Data Exchange (ETDEWEB)

    Takaro, K.; Naoki, T.; Satosi, K.; Yasutosi, K.

    1984-03-17

    A device is proposed which makes it possible to obtain single vertical mode emission in the absence of noise. Noise suppression is achieved by a method which determines the relationship between the donor densities in the second and third layers of an n type semiconductor laser, and the total output optical emission of layers with respect to the emission from the entire laser. The device consists of a photoresist film with a window applied to a 100 GaAs n type conductivity substrate using a standard method. Chemical etching through this window in the substrate is used to generate a slot approximately 1 micrometer in size. After the photoresist film is removed, the following layers are deposited from the liquid phase onto the substrate in the sequence indicated: a telurium doped protective layer of n type AlxGa(1-x) As; 2) an undoped active p type AlyGa(1-6) As layer and a tellurium doped upper protective n type conductivity GaAs layer.

  2. Resistive Switching Characteristics in Electrochemically Synthesized ZnO Films

    Directory of Open Access Journals (Sweden)

    Shuhan Jing

    2015-04-01

    Full Text Available The semiconductor industry has long been seeking a new kind of non-volatile memory technology with high-density, high-speed, and low-power consumption. This study demonstrated the electrochemical synthesis of ZnO films without adding any soft or hard templates. The effect of deposition temperatures on crystal structure, surface morphology and resistive switching characteristics were investigated. Our findings reveal that the crystallinity, surface morphology and resistive switching characteristics of ZnO thin films can be well tuned by controlling deposition temperature. A conducting filament based model is proposed to explain the switching mechanism in ZnO thin films.

  3. Manufacture of Radio Frequency Micromachined Switches with Annealing

    Directory of Open Access Journals (Sweden)

    Cheng-Yang Lin

    2014-01-01

    Full Text Available The fabrication and characterization of a radio frequency (RF micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspended structures of the switch. In order to improve the residual stress of the switch, an annealing process is applied to the switch, and the membrane obtains an excellent flatness. The finite element method (FEM software CoventorWare is utilized to simulate the stress and displacement of the RF switch. Experimental results show that the RF switch has an insertion loss of 0.9 dB at 35 GHz and an isolation of 21 dB at 39 GHz. The actuation voltage of the switch is 14 V.

  4. Manufacture of radio frequency micromachined switches with annealing.

    Science.gov (United States)

    Lin, Cheng-Yang; Dai, Ching-Liang

    2014-01-17

    The fabrication and characterization of a radio frequency (RF) micromachined switch with annealing were presented. The structure of the RF switch consists of a membrane, coplanar waveguide (CPW) lines, and eight springs. The RF switch is manufactured using the complementary metal oxide semiconductor (CMOS) process. The switch requires a post-process to release the membrane and springs. The post-process uses a wet etching to remove the sacrificial silicon dioxide layer, and to obtain the suspended structures of the switch. In order to improve the residual stress of the switch, an annealing process is applied to the switch, and the membrane obtains an excellent flatness. The finite element method (FEM) software CoventorWare is utilized to simulate the stress and displacement of the RF switch. Experimental results show that the RF switch has an insertion loss of 0.9 dB at 35 GHz and an isolation of 21 dB at 39 GHz. The actuation voltage of the switch is 14 V.

  5. IGBT Dynamic Loss Reduction through Device Level Soft Switching

    Directory of Open Access Journals (Sweden)

    Lan Ma

    2018-05-01

    Full Text Available Due to its low conduction loss, hence high current ratings, as well as low cost, Silicon Insulated Gate Bipolar Transistor (Si IGBT is widely used in high power applications. However, its switching frequency is generally low because of relatively large switching losses. Silicon carbide Metal-Oxide-Semiconductor Field-Effect Transistor (SiC MOSFET is much more superior due to their fast switching speed, which is determined by the internal parasitic capacitance instead of the stored charges, like the IGBT. By the combination of SiC MOSFET and Si IGBT, this paper presents a novel series hybrid switching method to achieve IGBT’s dynamic switching loss reduction by switching under Zero Voltage Hard Current (ZVHC turn-on and Zero Current Hard Voltage (ZCHV turn-off conditions. Both simulation and experimental results of IGBT are carried out, which shows that the soft switching of IGBT has been achieved both in turn-on and turn-off period. Thus 90% turn-on loss and 57% turn-off loss are reduced. Two different IGBTs’ test results are also provided to study the modulation parameter’s effect on the turn-off switching loss. Furthermore, with the consideration of voltage and current transient states, a new soft switching classification is proposed. At last, another improved modulation and Highly Efficient and Reliable Inverter Concept (HERIC inverter are given to validate the effectiveness of the device level hybrid soft switching method application.

  6. Analysis and modeling of resistive switching mechanisms oriented to resistive random-access memory

    International Nuclear Information System (INIS)

    Huang Da; Wu Jun-Jie; Tang Yu-Hua

    2013-01-01

    With the progress of the semiconductor industry, the resistive random-access memory (RAM) has drawn increasing attention. The discovery of the memristor has brought much attention to this study. Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms. We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models. Finally, simulations are presented. We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms, which are applied to explain their resistive switchings

  7. Prediction of left main or 3-vessel disease using myocardial perfusion reserve on dynamic thallium-201 single-photon emission computed tomography with a semiconductor gamma camera.

    Science.gov (United States)

    Shiraishi, Shinya; Sakamoto, Fumi; Tsuda, Noriko; Yoshida, Morikatsu; Tomiguchi, Seiji; Utsunomiya, Daisuke; Ogawa, Hisao; Yamashita, Yasuyuki

    2015-01-01

    Myocardial perfusion imaging (MPI) may fail to detect balanced ischemia. We evaluated myocardial perfusion reserve (MPR) using Tl dynamic single-photon emission computed tomography (SPECT) and a novel cadmium zinc telluride (CZT) camera for predicting 3-vessel or left main coronary artery disease (CAD). METHODS AND RESULTS: A total of 55 consecutive patients with suspected CAD underwent SPECT-MPI and coronary angiography. The MPR index was calculated using the standard 2-compartment kinetic model. We analyzed the utility of MPR index, other SPECT findings, and various clinical variables. On multivariate analysis, MPR index and history of previous myocardial infarction (MI) predicted left main and 3-vessel disease. The area under the receiver operating characteristic curve was 0.81 for MPR index, 0.699 for history of previous MI, and 0.86 for MPR index plus history of previous MI. MPR index ≤1.5 yielded the highest diagnostic accuracy. Sensitivity, specificity, and accuracy were 86%, 78%, and 80%, respectively, for MPR index, 64%, 76%, 73% for previous MI, and 57%, 93%, and 84% for MPR index plus history of previous MI. Quantification of MPR using dynamic SPECT and a novel CZT camera may identify balanced ischemia in patients with left main or 3-vessel disease.

  8. Physics with isotopically controlled semiconductors

    International Nuclear Information System (INIS)

    Haller, E.E.

    1994-08-01

    Control of the isotopic composition of semiconductors offers a wide range of new scientific opportunities. In this paper a number of recent results obtained with isotopically pure as well as deliberately mixed diamond and Ge bulk single crystals and Ge isotope superlattices will be reviewed. Isotopic composition affects several properties such as phonon energies, bandstructure and lattice constant in subtle but theoretically well understood ways. Large effects are observed for thermal conductivity, local vibrational modes of impurities and after neutron transmutation doping (NTD). Several experiments which could profit greatly from isotope control are proposed

  9. Application of nanomaterials in two-terminal resistive-switching memory devices

    Directory of Open Access Journals (Sweden)

    Jianyong Ouyang

    2010-05-01

    Full Text Available Nanometer materials have been attracting strong attention due to their interesting structure and properties. Many important practical applications have been demonstrated for nanometer materials based on their unique properties. This article provides a review on the fabrication, electrical characterization, and memory application of two-terminal resistive-switching devices using nanomaterials as the active components, including metal and semiconductor nanoparticles (NPs, nanotubes, nanowires, and graphenes. There are mainly two types of device architectures for the two-terminal devices with NPs. One has a triple-layer structure with a metal film sandwiched between two organic semiconductor layers, and the other has a single polymer film blended with NPs. These devices can be electrically switched between two states with significant different resistances, i.e. the ‘ON’ and ‘OFF’ states. These render the devices important application as two-terminal non-volatile memory devices. The electrical behavior of these devices can be affected by the materials in the active layer and the electrodes. Though the mechanism for the electrical switches has been in argument, it is generally believed that the resistive switches are related to charge storage on the NPs. Resistive switches were also observed on crossbars formed by nanotubes, nanowires, and graphene ribbons. The resistive switches are due to nanoelectromechanical behavior of the materials. The Coulombic interaction of transient charges on the nanomaterials affects the configurable gap of the crossbars, which results into significant change in current through the crossbars. These nanoelectromechanical devices can be used as fast-response and high-density memory devices as well. Dr. Jianyong Ouyang received his bachelor degree from the Tsinghua University in Beijing, China, and MSc from the Institute of Chemistry, Chinese Academy of Science. He received his PhD from the Institute for Molecular

  10. Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface

    International Nuclear Information System (INIS)

    Adib, Ehsan; Farzanehfard, Hosein

    2009-01-01

    In this paper a new soft switching bidirectional DC-DC converter is introduced which can be applied as the interface circuit between ultracapacitors and batteries or fuel cells. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. Due to achieved soft switching condition, the energy conversion through the proposed converter is highly efficient. The proposed converter is analyzed and a prototype converter is implemented. The presented experimental results confirm the theoretical analysis.

  11. Soft switching bidirectional DC-DC converter for ultracapacitor-batteries interface

    Energy Technology Data Exchange (ETDEWEB)

    Adib, Ehsan; Farzanehfard, Hosein [Dept. of Electrical and Computer Engineering, Isfahan Univ. of Technology (Iran)

    2009-12-15

    In this paper a new soft switching bidirectional DC-DC converter is introduced which can be applied as the interface circuit between ultracapacitors and batteries or fuel cells. All semiconductor devices in the proposed converter are soft switched while the control circuit remains PWM. Due to achieved soft switching condition, the energy conversion through the proposed converter is highly efficient. The proposed converter is analyzed and a prototype converter is implemented. The presented experimental results confirm the theoretical analysis. (author)

  12. Analysis of High Switching Frequency Quasi-Z-Source Photovoltaic Inverter Using Wide Bandgap Devices

    Science.gov (United States)

    Kayiranga, Thierry

    Power inverters continue to play a key role in todays electrical system more than ever. Power inverters employ power semiconductors to converter direct current (DC) into alternating current (AC). The performance of the semiconductors is based on speed and efficiency. Until recently, Silicon (Si) semiconductors had been established as mature. However, the continuous optimization and improvements in the production process of Si to meet today technology requirements have pushed Si materials to their theoretical limits. In an effort to find a suitable replacement, wide bandgap devices mainly Gallium Nitride (GaN) and Silicon Carbide (SiC), have proved to be excellent candidates offering high operation temperature, high blocking voltage and high switching frequency; of which the latter makes GaN a better candidate in high switching low voltage in Distributed Generations (DG). The single stage Quasi-Z-Source Inverter (qZSI) is also able to draw continuous and constant current from the source making ideal for PV applications in addition to allowing shoot-through states. The qZSI find best applications in medium level ranges where multiples qZS inverters can be cascaded (qZS-CMI) by combining the benefit of the qZSI, boost capabilities and continuous and constant input current, and those of the CMI, low output harmonic content and independent MPPT. When used with GaN devices operating at very high frequency, the qZS network impedance can be significantly reduced. However, the impedance network becomes asymmetric. The asymmetric impedance network (AIN-qZSI) has several advantages such as increased power density, increases system lifetime, small size volume and size making it more attractive for module integrated converter (MIC) concepts. However, there are technical challenges. With asymmetric component, resonance is introduced in the system leading to more losses and audible noise. With small inductances, new operation states become available further increasing the system

  13. Defects in semiconductors

    International Nuclear Information System (INIS)

    Pimentel, C.A.F.

    1983-01-01

    Some problems openned in the study of defects in semiconductors are presented. In particular, a review is made of the more important problems in Si monocrystals of basic and technological interest: microdefects and the presence of oxigen and carbon. The techniques usually utilized in the semiconductor material characterization are emphatized according its potentialities. Some applications of x-ray techniques in the epitaxial shell characterization in heterostructures, importants in electronic optics, are shown. The increase in the efficiency of these defect analysis methods in semiconductor materials with the use of synchrotron x-ray sources is shown. (L.C.) [pt

  14. Introduction to Semiconductor Devices

    Science.gov (United States)

    Brennan, Kevin F.

    2005-03-01

    This volume offers a solid foundation for understanding the most important devices used in the hottest areas of electronic engineering today, from semiconductor fundamentals to state-of-the-art semiconductor devices in the telecommunications and computing industries. Kevin Brennan describes future approaches to computing hardware and RF power amplifiers, and explains how emerging trends and system demands of computing and telecommunications systems influence the choice, design and operation of semiconductor devices. In addition, he covers MODFETs and MOSFETs, short channel effects, and the challenges faced by continuing miniaturization. His book is both an excellent senior/graduate text and a valuable reference for practicing engineers and researchers.

  15. Spin physics in semiconductors

    CERN Document Server

    2017-01-01

    This book offers an extensive introduction to the extremely rich and intriguing field of spin-related phenomena in semiconductors. In this second edition, all chapters have been updated to include the latest experimental and theoretical research. Furthermore, it covers the entire field: bulk semiconductors, two-dimensional semiconductor structures, quantum dots, optical and electric effects, spin-related effects, electron-nuclei spin interactions, Spin Hall effect, spin torques, etc. Thanks to its self-contained style, the book is ideally suited for graduate students and researchers new to the field.

  16. Physics of semiconductor lasers

    CERN Document Server

    Mroziewicz, B; Nakwaski, W

    2013-01-01

    Written for readers who have some background in solid state physics but do not necessarily possess any knowledge of semiconductor lasers, this book provides a comprehensive and concise account of fundamental semiconductor laser physics, technology and properties. The principles of operation of these lasers are therefore discussed in detail with the interrelations between their design and optical, electrical and thermal properties. The relative merits of a large number of laser structures and their parameters are described to acquaint the reader with the various aspects of the semiconductor l

  17. Semiconductors bonds and bands

    CERN Document Server

    Ferry, David K

    2013-01-01

    As we settle into this second decade of the twenty-first century, it is evident that the advances in micro-electronics have truly revolutionized our day-to-day lifestyle. The technology is built upon semiconductors, materials in which the band gap has been engineered for special values suitable to the particular application. This book, written specifically for a one semester course for graduate students, provides a thorough understanding of the key solid state physics of semiconductors. It describes how quantum mechanics gives semiconductors unique properties that enabled the micro-electronics revolution, and sustain the ever-growing importance of this revolution.

  18. Defects in semiconductors

    CERN Document Server

    Romano, Lucia; Jagadish, Chennupati

    2015-01-01

    This volume, number 91 in the Semiconductor and Semimetals series, focuses on defects in semiconductors. Defects in semiconductors help to explain several phenomena, from diffusion to getter, and to draw theories on materials' behavior in response to electrical or mechanical fields. The volume includes chapters focusing specifically on electron and proton irradiation of silicon, point defects in zinc oxide and gallium nitride, ion implantation defects and shallow junctions in silicon and germanium, and much more. It will help support students and scientists in their experimental and theoret

  19. Electrodynamics of the semiconductor band edge

    International Nuclear Information System (INIS)

    Stahl, A.; Balslev, I.

    1987-01-01

    The book is a presentation of an approach to electrodynamics in semiconductors. It describes in detail the coherence phenomena appearing when the electromagnetic wavelength, the electron-hole coherence length and the single-particle wavelength are of the same order of magnitude

  20. Ultranarrow polaritons in a semiconductor microcavity

    DEFF Research Database (Denmark)

    Jensen, Jacob Riis; Borri, Paola; Langbein, Wolfgang

    2000-01-01

    We have achieved a record high ratio (19) of the Rabi splitting (3.6 meV) to the polariton linewidth (190 mu eV), in a semiconductor lambda microcavity with a single 25 nm GaAs quantum well at the antinode. The narrow polariton lines are obtained with a special cavity design which reduces...

  1. Electron Spins in Semiconductor Quantum Dots

    NARCIS (Netherlands)

    Hanson, R.

    2005-01-01

    This thesis describes a series of experiments aimed at understanding and controlling the behavior of the spin degree of freedom of single electrons, confined in semiconductor quantum dots. This research work is motivated by the prospects of using the electron spin as a quantum bit (qubit), the basic

  2. Light-controlled supramolecular helicity of a liquid crystalline phase using a helical polymer functionalized with a single chiroptical molecular switch

    NARCIS (Netherlands)

    Pijper, Dirk; Jongejan, Mahthild G. M.; Meetsma, Auke; Feringa, Ben L.

    2008-01-01

    Control over the preferred helical sense of a poly(n-hexyl isocyanate) (PHIC) by using a single light-driven molecular motor, covalently attached at the polymer's terminus, has been accomplished in solution via a combination of photochemical and thermal isomerizations. Here, we report that after

  3. Latching micro optical switch

    Science.gov (United States)

    Garcia, Ernest J; Polosky, Marc A

    2013-05-21

    An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

  4. Development of pulsation technique for single ion hit system

    Energy Technology Data Exchange (ETDEWEB)

    Sakai, Takuro; Hamano, Tsuyoshi; Hirao, Toshio; Kamiya, Tomihiro [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    1996-12-01

    When a high energy heavy ion enters into a substance, high density of ionization and excitement occurrs along its flying trace. Especially, when such an ion enters into a semiconductor cell, a bit inversion called single event is occurred or a phenomenon destroyed element itself on case of the worst is formed. The present semiconductor cell is made in a size of some micron square, as different from its accumulated degree. In order to analyze the single event phenomenon formed by entering ion into such fine region in detail, a technique possible enter heavy ion beam with space resolution under 1 micron to each sample is necessary. In order to develop this technique, a static type high speed beam switch for control of entering a beam into a sample and a single ion detector for detecting entrance of ion into the sample were installed to heavy ion microbeam forming apparatus. The single ion hit system in Takasaki Radiation Chemistry Research Establishment, JAERI succeeded in detection and control technique of the single ion and control of noise due to pulsization and finished development of basic technique of the single ion hit, since now. After today, it is planned to hit actually the single ion onto the sample and evaluate its accuracy. (G.K.)

  5. Biggest semiconductor installed

    CERN Multimedia

    2008-01-01

    Scientists and technicians at the European Laboratory for Particle Physics, commonly known by its French acronym CERN (Centre Europen pour la Recherche Nuclaire), have completed the installation of the largest semiconductor silicon detector.

  6. High Current, Multi-Filament Photoconductive Semiconductor Switching

    Science.gov (United States)

    2011-06-01

    width (T=5 ns), and the volume in which the photons are absorbed ( lwd , where d=0.2-10 µm is the absorption depth, l=2.5 mm is the line length, and w=10...µm is the line width): n = (E/Eph) q (1-R) (1-e(- τ/T)) ⁄ ( lwd ) (1) The extremes for the values and ranges listed above give n=2×1017-5

  7. Optically coupled cavities for wavelength switching

    Energy Technology Data Exchange (ETDEWEB)

    Costazo-Caso, Pablo A; Granieri, Sergio; Siahmakoun, Azad, E-mail: pcostanzo@ing.unlp.edu.ar, E-mail: granieri@rose-hulman.edu, E-mail: siahmako@rose-hulman.edu [Department of Physics and Optical Engineering, Rose-Hulman Institute of Technology, 5500 Wabash Avenue, Terre Haute, IN 47803 (United States)

    2011-01-01

    An optical bistable device which presents hysteresis behavior is proposed and experimentally demonstrated. The system finds applications in wavelength switching, pulse reshaping and optical bistability. It is based on two optically coupled cavities named master and slave. Each cavity includes a semiconductor optical amplifier (SOA), acting as the gain medium of the laser, and two pair of fiber Bragg gratings (FBG) which define the lasing wavelength (being different in each cavity). Finally, a variable optical coupler (VOC) is employed to couple both cavities. Experimental characterization of the system performance is made analyzing the effects of the coupling coefficient between the two cavities and the driving current in each SOA. The properties of the hysteretic bistable curve and switching can be controlled by adjusting these parameters and the loss in the cavities. By selecting the output wavelength ({lambda}{sub 1} or {lambda}{sub 2}) with an external filter it is possible to choose either the invert or non-invert switched signal. Experiments were developed employing both optical discrete components and a photonic integrated circuit. They show that for 8 m-long cavities the maximum switching frequency is about 500 KHz, and for 4 m-long cavities a minimum rise-time about 21 ns was measured. The switching time can be reduced by shortening the cavity lengths and using photonic integrated circuits.

  8. Radiation effects in semiconductors

    CERN Document Server

    2011-01-01

    There is a need to understand and combat potential radiation damage problems in semiconductor devices and circuits. Written by international experts, this book explains the effects of radiation on semiconductor devices, radiation detectors, and electronic devices and components. These contributors explore emerging applications, detector technologies, circuit design techniques, new materials, and innovative system approaches. The text focuses on how the technology is being used rather than the mathematical foundations behind it. It covers CMOS radiation-tolerant circuit implementations, CMOS pr

  9. Market survey of semiconductors

    International Nuclear Information System (INIS)

    Mackintosh, I.M.; Diegel, D.; Brown, A.; Brinker, C.S. den

    1977-06-01

    Examination of technology and product trends over the range of current and future products in integrated circuits and optoelectronic displays. Analysis and forecast of major economic influences that affect the production costs of integrated circuits and optoelectronic displays. Forecast of the applications and markets for integrated circuits up to 1985 in West Europe, the USA and Japan. Historic development of the semiconductor industry and the prevailing tendencies - factors which influence success in the semiconductor industry. (orig.) [de

  10. Laser vapor phase deposition of semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Karlov, N.V.; Luk' ianchuk, B.S.; Sisakian, E.V.; Shafeev, G.A.

    1987-06-01

    The pyrolytic effect of IR laser radiation is investigated with reference to the initiation and control of the vapor phase deposition of semiconductor films. By selecting the gas mixture composition and laser emission parameters, it is possible to control the deposition and crystal formation processes on the surface of semiconductors, with the main control action achieved due to the nonadiabatic kinetics of reactions in the gas phase and high temperatures in the laser heating zone. This control mechanism is demonstrated experimentally during the laser vapor deposition of germanium and silicon films from tetrachlorides on single-crystal Si and Ge substrates. 5 references.

  11. Novel room temperature ferromagnetic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Amita [KTH Royal Inst. of Technology, Stockholm (Sweden)

    2004-06-01

    Today's information world, bits of data are processed by semiconductor chips, and stored in the magnetic disk drives. But tomorrow's information technology may see magnetism (spin) and semiconductivity (charge) combined in one 'spintronic' device that exploits both charge and 'spin' to carry data (the best of two worlds). Spintronic devices such as spin valve transistors, spin light emitting diodes, non-volatile memory, logic devices, optical isolators and ultra-fast optical switches are some of the areas of interest for introducing the ferromagnetic properties at room temperature in a semiconductor to make it multifunctional. The potential advantages of such spintronic devices will be higher speed, greater efficiency, and better stability at a reduced power consumption. This Thesis contains two main topics: In-depth understanding of magnetism in Mn doped ZnO, and our search and identification of at least six new above room temperature ferromagnetic semiconductors. Both complex doped ZnO based new materials, as well as a number of nonoxides like phosphides, and sulfides suitably doped with Mn or Cu are shown to give rise to ferromagnetism above room temperature. Some of the highlights of this work are discovery of room temperature ferromagnetism in: (1) ZnO:Mn (paper in Nature Materials, Oct issue, 2003); (2) ZnO doped with Cu (containing no magnetic elements in it); (3) GaP doped with Cu (again containing no magnetic elements in it); (4) Enhancement of Magnetization by Cu co-doping in ZnO:Mn; (5) CdS doped with Mn, and a few others not reported in this thesis. We discuss in detail the first observation of ferromagnetism above room temperature in the form of powder, bulk pellets, in 2-3 mu-m thick transparent pulsed laser deposited films of the Mn (<4 at. percent) doped ZnO. High-resolution transmission electron microscopy (HRTEM) and electron energy loss spectroscopy (EELS) spectra recorded from 2 to 200nm areas showed homogeneous

  12. Investigation of a metal-organic interface. Realization and understanding of a molecular switch

    Energy Technology Data Exchange (ETDEWEB)

    Neucheva, Olga [Forschungszentrum Juelich (DE). Institute of Bio- and Nanosystems (IBN), Functional Nanostructures at Surfaces (IBN-3)

    2010-07-01

    The field of molecular organic electronics is an emerging and very dynamic area. The continued trend to miniaturisation, combined with increasing complexity and cost of production in conventional semiconductor electronics, forces companies to turn their attention to alternatives that promise the next levels of scale at significantly lower cost. After consumer electronic devices based on organic transistors, such as TVs and book readers, have already been presented, molecular electronics is expected to offer the next breakthrough in feature size. Unfortunately, most of the organic/metal interfaces contain intrinsic defects that break the homogeneity of the interface properties. In this thesis, the electronic and structural properties of such defects were examined in order to understand the influence of the inhomogeneities on the quality of the interface layer. However, the main focus of this work was the investigation of the local properties of a single molecule. Taking advantage of the Scanning Tunnelling Microscope's (STM's) ability to act as a local probe, a single molecular switch was realized and studied. Moreover, in close collaboration with theory groups, the underlying mechanism driving the switching process was identified and described. Besides the investigation of the switching process, the ability of the STM to build nanostructures of different shapes from large organic molecules was shown. Knowing the parameters for realization and control of the switching process and for building the molecular corrals, the results of this investigation enable the reconstruction of the studied molecular ensemble and its deployment in electric molecular circuits, constituting a next step towards further miniaturization of electronic devices. (orig.)

  13. Acoustic charge manipulation in semiconductor nanostructures for optical applications

    Energy Technology Data Exchange (ETDEWEB)

    Voelk, Stefan

    2010-07-30

    Within this thesis, the influence of a surface acoustic wave (SAW) on the luminescence of semiconductor nanostructures is investigated. Beginning with the physics of low-dimensional semiconductor structures, the quantum mechanical and optical properties of quantum dot (QD) systems are discussed. In particular, intrinsic parameters of QDs such as morphology, composition, strain and occupation with carriers are taken into account. Subsequently, the influence of an applied electric field and of externally induced strain are introduced. From this general approach, the discussion is focused to quantum posts (QPs) which are columnar shaped semiconductor nanostructures. In contrast to conventional self-assembled QDs, the height of the QPs can be controlled by the epitaxial growth process. Due to the adjustable height, electronic states and therefore the exciton transition energies can be tailored. Furthermore, QPs are embedded in a matrix-quantum-well structure which has important influence on the carrier dynamic if a SAW is excited on the sample. Mainly, two effects have to be considered regarding the interaction of charge carriers with SAWs: deformation potential coupling and acousto-electric coupling. For the investigated material and used SAW frequencies, acousto-electric coupling dominates the interaction between charges and SAW. For a quantum well (QW) structure, the periodic band modulation dissociates excitons into sequential stripes of electrons and holes which then are conveyed by the SAW. This so called bipolar transport or charge conveyance effect can be used to inject carriers into remote QD structures and has already been demonstrated for QD ensembles. The injection of carriers into individual quantum posts is successfully demonstrated for the first time within this work. The spectrally resolved photoluminescence (PL) data of individual QPs show an unexpected switching of PL lines which cannot be induced by varying other parameters, e.g. the laser intensity

  14. Semiconductor laser using multimode interference principle

    Science.gov (United States)

    Gong, Zisu; Yin, Rui; Ji, Wei; Wu, Chonghao

    2018-01-01

    Multimode interference (MMI) structure is introduced in semiconductor laser used in optical communication system to realize higher power and better temperature tolerance. Using beam propagation method (BPM), Multimode interference laser diode (MMI-LD) is designed and fabricated in InGaAsP/InP based material. As a comparison, conventional semiconductor laser using straight single-mode waveguide is also fabricated in the same wafer. With a low injection current (about 230 mA), the output power of the implemented MMI-LD is up to 2.296 mW which is about four times higher than the output power of the conventional semiconductor laser. The implemented MMI-LD exhibits stable output operating at the wavelength of 1.52 μm and better temperature tolerance when the temperature varies from 283.15 K to 293.15 K.

  15. Oxide Ferromagnetic Semiconductors for Spin-Electronic Transprt

    International Nuclear Information System (INIS)

    Pandey, R.K.

    2008-01-01

    The objective of this research was to investigate the viability of oxide magnetic semiconductors as potential materials for spintronics. We identified some members of the solid solution series of ilmenite (FeTiO3) and hematite (Fe2O3), abbreviated as (IH) for simplicity, for our investigations based on their ferromagnetic and semiconducting properties. With this objective in focus we limited our investigations to the following members of the modified Fe-titanates: IH33 (ilmenitehematite with 33 atomic percent hematite), IH45 (ilmenite-hematite with 45 atomic percent hematite), Mn-substituted ilmenite (Mn-FeTiO3), and Mn-substituted pseudobrookite (Mn- Fe2TiO5). All of them are: (1) wide bandgap semiconductors with band gaps ranging in values between 2.5 to 3.5 eV; (2) n-type semiconductors; (3) they exhibit well defined magnetic hysteresis loops and (4) their magnetic Curie points are greater than 400K. Ceramic, film and single crystal samples were studied and based on their properties we produced varistors (also known as voltage dependent resistors) for microelectronic circuit protection from power surges, three-terminal microelectronic devices capable of generating bipolar currents, and an integrated structured device with controlled magnetic switching of spins. Eleven refereed journal papers, three refereed conference papers and three invention disclosures resulted from our investigations. We also presented invited papers in three international conferences and one national conference. Furthermore two students graduated with Ph.D. degrees, three with M.S. degrees and one with B.S. degree. Also two post-doctoral fellows were actively involved in this research. We established the radiation hardness of our devices in collaboration with a colleague in an HBCU institution, at the Cyclotron Center at Texas A and M University, and at DOE National Labs (Los Alamos and Brookhaven). It is to be appreciated that we met most of our goals and expanded vastly the scope of

  16. Temperature dependent electronic conduction in semiconductors

    International Nuclear Information System (INIS)

    Roberts, G.G.; Munn, R.W.

    1980-01-01

    This review describes the temperature dependence of bulk-controlled electronic currents in semiconductors. The scope of the article is wide in that it contrasts conduction mechanisms in inorganic and organic solids and also single crystal and disordered semiconductors. In many experimental situations it is the metal-semiconductor contact or the interface between two dissimilar semiconductors that governs the temperature dependence of the conductivity. However, in order to keep the length of the review within reasonable bounds, these topics have been largely avoided and emphasis is therefore placed on bulk-limited currents. A central feature of electronic conduction in semiconductors is the concentrations of mobile electrons and holes that contribute to the conductivity. Various statistical approaches may be used to calculate these densities which are normally strongly temperature dependent. Section 1 emphasizes the relationship between the position of the Fermi level, the distribution of quantum states, the total number of electrons available and the absolute temperature of the system. The inclusion of experimental data for several materials is designed to assist the experimentalist in his interpretation of activation energy curves. Sections 2 and 3 refer to electronic conduction in disordered solids and molecular crystals, respectively. In these cases alternative approaches to the conventional band theory approach must be considered. For example, the velocities of the charge carriers are usually substantially lower than those in conventional inorganic single crystal semiconductors, thus introducing the possibility of an activated mobility. Some general electronic properties of these materials are given in the introduction to each of these sections and these help to set the conduction mechanisms in context. (orig.)

  17. Validating an infrared thermal switch as a novel access technology

    Directory of Open Access Journals (Sweden)

    Memarian Negar

    2010-08-01

    Full Text Available Abstract Background Recently, a novel single-switch access technology based on infrared thermography was proposed. The technology exploits the temperature differences between the inside and surrounding areas of the mouth as a switch trigger, thereby allowing voluntary switch activation upon mouth opening. However, for this technology to be clinically viable, it must be validated against a gold standard switch, such as a chin switch, that taps into the same voluntary motion. Methods In this study, we report an experiment designed to gauge the concurrent validity of the infrared thermal switch. Ten able-bodied adults participated in a series of 3 test sessions where they simultaneously used both an infrared thermal and conventional chin switch to perform multiple trials of a number identification task with visual, auditory and audiovisual stimuli. Participants also provided qualitative feedback about switch use. User performance with the two switches was quantified using an efficiency measure based on mutual information. Results User performance (p = 0.16 and response time (p = 0.25 with the infrared thermal switch were comparable to those of the gold standard. Users reported preference for the infrared thermal switch given its non-contact nature and robustness to changes in user posture. Conclusions Thermal infrared access technology appears to be a valid single switch alternative for individuals with disabilities who retain voluntary mouth opening and closing.

  18. Cavity-photon-switched coherent transient transport in a double quantum waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Nzar Rauf, E-mail: nra1@hi.is; Gudmundsson, Vidar, E-mail: vidar@raunvis.hi.is [Science Institute, University of Iceland, Dunhaga 3, IS-107 Reykjavik (Iceland); Tang, Chi-Shung [Department of Mechanical Engineering, National United University, 1, Lienda, 36003 Miaoli, Taiwan (China); Manolescu, Andrei [School of Science and Engineering, Reykjavik University, Menntavegur 1, IS-101 Reykjavik (Iceland)

    2014-12-21

    We study a cavity-photon-switched coherent electron transport in a symmetric double quantum waveguide. The waveguide system is weakly connected to two electron reservoirs, but strongly coupled to a single quantized photon cavity mode. A coupling window is placed between the waveguides to allow electron interference or inter-waveguide transport. The transient electron transport in the system is investigated using a quantum master equation. We present a cavity-photon tunable semiconductor quantum waveguide implementation of an inverter quantum gate, in which the output of the waveguide system may be selected via the selection of an appropriate photon number or “photon frequency” of the cavity. In addition, the importance of the photon polarization in the cavity, that is, either parallel or perpendicular to the direction of electron propagation in the waveguide system is demonstrated.

  19. Reluctance motor employing superconducting magnetic flux switches

    International Nuclear Information System (INIS)

    Spyker, R.L.; Ruckstadter, E.J.

    1992-01-01

    This paper reports that superconducting flux switches controlling the magnetic flux in the poles of a motor will enable the implementation of a reluctance motor using one central single phase winding. A superconducting flux switch consists of a ring of superconducting material surrounding a ferromagnetic pole of the motor. When in the superconducting state the switch will block all magnetic flux attempting to flow in the ferromagnetic core. When switched to the normal state the superconducting switch will allow the magnetic flux to flow freely in that pole. By using one high turns-count coil as a flux generator, and selectively channeling flux among the various poles using the superconducting flux switch, 3-phase operation can be emulated with a single-hase central AC source. The motor will also operate when the flux generating coil is driven by a DC current, provided the magnetic flux switches see a continuously varying magnetic flux. Rotor rotation provides this varying flux due to the change in stator pole inductance it produces

  20. Method of doping a semiconductor

    International Nuclear Information System (INIS)

    Yang, C.Y.; Rapp, R.A.

    1983-01-01

    A method is disclosed for doping semiconductor material. An interface is established between a solid electrolyte and a semiconductor to be doped. The electrolyte is chosen to be an ionic conductor of the selected impurity and the semiconductor material and electrolyte are jointly chosen so that any compound formed from the impurity and the semiconductor will have a free energy no lower than the electrolyte. A potential is then established across the interface so as to allow the impurity ions to diffuse into the semiconductor. In one embodiment the semiconductor and electrolyte may be heated so as to increase the diffusion coefficient

  1. Elastomeric organic material for switching application

    Energy Technology Data Exchange (ETDEWEB)

    Shiju, K., E-mail: shijuvenus@gmail.com, E-mail: pravymon@gmail.com, E-mail: ppredeep@gmail.com; Praveen, T., E-mail: shijuvenus@gmail.com, E-mail: pravymon@gmail.com, E-mail: ppredeep@gmail.com; Preedep, P., E-mail: shijuvenus@gmail.com, E-mail: pravymon@gmail.com, E-mail: ppredeep@gmail.com [Laboratory for Molecular Photonics and Electronics (LAMP), Department of Physics, National Institute of Technology, Calicut, Kerala, 673601 (India)

    2014-10-15

    Organic Electronic devices like OLED, Organic Solar Cells etc are promising as, cost effective alternatives to their inorganic counterparts due to various reasons. However the organic semiconductors currently available are not attractive with respect to their high cost and intricate synthesis protocols. Here we demonstrate that Natural Rubber has the potential to become a cost effective solution to this. Here an attempt has been made to fabricate iodine doped poly isoprene based switching device. In this work Poly methyl methacrylate is used as dielectric layer and Aluminium are employed as electrodes.

  2. Transition metal redox switches for reversible "on/off" and "slow/fast" single-molecule magnet behaviour in dysprosium and erbium bis-diamidoferrocene complexes.

    Science.gov (United States)

    Dickie, Courtney M; Laughlin, Alexander L; Wofford, Joshua D; Bhuvanesh, Nattamai S; Nippe, Michael

    2017-12-01

    Single-molecule magnets (SMMs) are considered viable candidates for next-generation data storage and quantum computing. Systems featuring switchability of their magnetization dynamics are particularly interesting with respect to accessing more complex logic gates and device architectures. Here we show that transition metal based redox events can be exploited to enable reversible switchability of slow magnetic relaxation of magnetically anisotropic lanthanide ions. Specifically, we report anionic homoleptic bis-diamidoferrocene complexes of Dy 3+ (oblate) and Er 3+ (prolate) which can be reversibly oxidized by one electron to yield their respective charge neutral redox partners (Dy: [1] - , 1 ; Er: [2] - , 2 ). Importantly, compounds 1 and 2 are thermally stable which allowed for detailed studies of their magnetization dynamics. We show that the Dy 3+ [1] - / 1 system can function as an "on"/"off" or a "slow"/"fast" redox switchable SMM system in the absence or presence of applied dc fields, respectively. The Er 3+ based [2] - / 2 system features "on"/"off" switchability of SMM properties in the presence of applied fields. Results from electrochemical investigations, UV-vis-NIR spectroscopy, and 57 Fe Mössbauer spectroscopy indicate the presence of significant electronic communication between the mixed-valent Fe ions in 1 and 2 in both solution and solid state. This comparative evaluation of redox-switchable magnetization dynamics in low coordinate lanthanide complexes may be used as a potential blueprint toward the development of future switchable magnetic materials.

  3. Development of the power control system for semiconductor lasers

    International Nuclear Information System (INIS)

    Kim, Kwang Suk; Kim, Cheol Jung

    1997-12-01

    For the first year plan of this program, we developed the power control system for semiconductor lasers. We applied the high-current switching mode techniques to fabricating a power control system. Then, we investigated the direct side pumping techniques with GaA1As diode laser bars to laser crystal without pumping optics. We obtained 0.5W average output power from this DPSSL. (author). 54 refs., 3 tabs., 18 figs

  4. Fundamentals of semiconductor lasers

    CERN Document Server

    Numai, Takahiro

    2015-01-01

    This book explains physics under the operating principles of semiconductor lasers in detail based on the experience of the author, dealing with the first manufacturing of phase-shifted DFB-LDs and recent research on transverse modes.   The book also bridges a wide gap between journal papers and textbooks, requiring only an undergraduate-level knowledge of electromagnetism and quantum mechanics, and helps readers to understand journal papers where definitions of some technical terms vary, depending on the paper. Two definitions of the photon density in the rate equations and two definitions of the phase-shift in the phase-shifted DFB-LD are explained, and differences in the calculated results are indicated, depending on the definitions.    Readers can understand the physics of semiconductor lasers and analytical tools for Fabry-Perot LDs, DFB-LDs, and VCSELs and will be stimulated to develop semiconductor lasers themselves.

  5. Coherent dynamics in semiconductors

    DEFF Research Database (Denmark)

    Hvam, Jørn Märcher

    1998-01-01

    enhanced in quantum confined lower-dimensional systems, where exciton and biexciton effects dominate the spectra even at room temperature. The coherent dynamics of excitons are at modest densities well described by the optical Bloch equations and a number of the dynamical effects known from atomic......Ultrafast nonlinear optical spectroscopy is used to study the coherent dynamics of optically excited electron-hole pairs in semiconductors. Coulomb interaction implies that the optical inter-band transitions are dominated, at least at low temperatures, by excitonic effects. They are further...... and molecular systems are found and studied in the exciton-biexciton system of semiconductors. At densities where strong exciton interactions, or many-body effects, become dominant, the semiconductor Bloch equations present a more rigorous treatment of the phenomena Ultrafast degenerate four-wave mixing is used...

  6. Hydrogen in semiconductors II

    CERN Document Server

    Nickel, Norbert H; Weber, Eicke R; Nickel, Norbert H

    1999-01-01

    Since its inception in 1966, the series of numbered volumes known as Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. The "Willardson and Beer" Series, as it is widely known, has succeeded in publishing numerous landmark volumes and chapters. Not only did many of these volumes make an impact at the time of their publication, but they continue to be well-cited years after their original release. Recently, Professor Eicke R. Weber of the University of California at Berkeley joined as a co-editor of the series. Professor Weber, a well-known expert in the field of semiconductor materials, will further contribute to continuing the series' tradition of publishing timely, highly relevant, and long-impacting volumes. Some of the recent volumes, such as Hydrogen in Semiconductors, Imperfections in III/V Materials, Epitaxial Microstructures, High-Speed Heterostructure Devices, Oxygen in Silicon, and others promise that this tradition ...

  7. Photoelectronic properties of semiconductors

    CERN Document Server

    Bube, Richard H

    1992-01-01

    The interaction between light and electrons in semiconductors forms the basis for many interesting and practically significant properties. This book examines the fundamental physics underlying this rich complexity of photoelectronic properties of semiconductors, and will familiarise the reader with the relatively simple models that are useful in describing these fundamentals. The basic physics is also illustrated with typical recent examples of experimental data and observations. Following introductory material on the basic concepts, the book moves on to consider a wide range of phenomena, including photoconductivity, recombination effects, photoelectronic methods of defect analysis, photoeffects at grain boundaries, amorphous semiconductors, photovoltaic effects and photoeffects in quantum wells and superlattices. The author is Professor of Materials Science and Electrical Engineering at Stanford University, and has taught this material for many years. He is an experienced author, his earlier books having fo...

  8. Metal-semiconductor, composite radiation detectors

    International Nuclear Information System (INIS)

    Orvis, W.J.; Yee, J.H.; Fuess, D.

    1992-12-01

    In 1989, Naruse and Hatayama of Toshiba published a design for an increased efficiency x-ray detector. The design increased the efficiency of a semiconductor detector by interspersing layers of high-z metal within it. Semiconductors such as silicon make good, high-resolution radiation detectors, but they have low efficiency because they are low-z materials (z = 14). High-z metals, on the other hand, are good absorbers of high-energy photons. By interspersing high-z metal layers with semiconductor layers, Naruse and Hatayama combined the high absorption efficiency of the high-z metals with the good detection capabilities of a semiconductor. This project is an attempt to use the same design to produce a high-efficiency, room temperature gamma ray detector. By their nature, gamma rays require thicker metal layers to efficiently absorb them. These thicker layers change the behavior of the detector by reducing the resolution, compared to a solid state detector, and shifting the photopeak by a predictable amount. During the last year, the authors have procured and tested a commercial device with operating characteristics similar to those of a single layer of the composite device. They have modeled the radiation transport in a multi-layered device, to verify the initial calculations of layer thickness and composition. They have modeled the electrostatic field in different device designs to locate and remove high-field regions that can cause device breakdown. They have fabricated 14 single layer prototypes

  9. Semiconductor technology for reducing emissions and increasing efficiency

    Energy Technology Data Exchange (ETDEWEB)

    Duffin, B.; Frank, R. [Motorola Semiconductor Products Sector, Phoenix, AZ (United States)

    1997-12-31

    The cooperation and support of all industries are required to significantly impact a worldwide reduction in gaseous emissions that may contribute to climate change. Each industry also is striving to more efficiently utilize the resources that it consumes since this is both conservation for good citizenship and an intelligent approach to business. The semiconductor industry is also extremely concerned with these issues. However, semiconductor manufacturer`s products provide solutions for reduced emissions and increased efficiency in their industry, other industries and areas that can realize significant improvements through control technology. This paper will focus on semiconductor technologies of digital control, power switching and sensing to improve efficiency and reduce emissions in automotive, industrial, and office/home applications. 10 refs., 13 figs.

  10. Advances in semiconductor lasers

    CERN Document Server

    Coleman, James J; Jagadish, Chennupati

    2012-01-01

    Semiconductors and Semimetals has distinguished itself through the careful selection of well-known authors, editors, and contributors. Originally widely known as the ""Willardson and Beer"" Series, it has succeeded in publishing numerous landmark volumes and chapters. The series publishes timely, highly relevant volumes intended for long-term impact and reflecting the truly interdisciplinary nature of the field. The volumes in Semiconductors and Semimetals have been and will continue to be of great interest to physicists, chemists, materials scientists, and device engineers in academia, scien

  11. Superconductivity in doped semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bustarret, E., E-mail: Etienne.bustarret@neel.cnrs.fr

    2015-07-15

    A historical survey of the main normal and superconducting state properties of several semiconductors doped into superconductivity is proposed. This class of materials includes selenides, tellurides, oxides and column-IV semiconductors. Most of the experimental data point to a weak coupling pairing mechanism, probably phonon-mediated in the case of diamond, but probably not in the case of strontium titanate, these being the most intensively studied materials over the last decade. Despite promising theoretical predictions based on a conventional mechanism, the occurrence of critical temperatures significantly higher than 10 K has not been yet verified. However, the class provides an enticing playground for testing theories and devices alike.

  12. Semiconductor opto-electronics

    CERN Document Server

    Moss, TS; Ellis, B

    1972-01-01

    Semiconductor Opto-Electronics focuses on opto-electronics, covering the basic physical phenomena and device behavior that arise from the interaction between electromagnetic radiation and electrons in a solid. The first nine chapters of this book are devoted to theoretical topics, discussing the interaction of electromagnetic waves with solids, dispersion theory and absorption processes, magneto-optical effects, and non-linear phenomena. Theories of photo-effects and photo-detectors are treated in detail, including the theories of radiation generation and the behavior of semiconductor lasers a

  13. Compound semiconductor device physics

    CERN Document Server

    Tiwari, Sandip

    2013-01-01

    This book provides one of the most rigorous treatments of compound semiconductor device physics yet published. A complete understanding of modern devices requires a working knowledge of low-dimensional physics, the use of statistical methods, and the use of one-, two-, and three-dimensional analytical and numerical analysis techniques. With its systematic and detailed**discussion of these topics, this book is ideal for both the researcher and the student. Although the emphasis of this text is on compound semiconductor devices, many of the principles discussed will also be useful to those inter

  14. Introductory semiconductor device physics

    CERN Document Server

    Parker, Greg

    2004-01-01

    ATOMS AND BONDINGThe Periodic TableIonic BondingCovalent BondingMetallic bondingvan der Waals BondingStart a DatabaseENERGY BANDS AND EFFECTIVE MASSSemiconductors, Insulators and MetalsSemiconductorsInsulatorsMetalsThe Concept of Effective MassCARRIER CONCENTRATIONS IN SEMICONDUCTORSDonors and AcceptorsFermi-LevelCarrier Concentration EquationsDonors and Acceptors Both PresentCONDUCTION IN SEMICONDUCTORSCarrier DriftCarrier MobilitySaturated Drift VelocityMobility Variation with TemperatureA Derivation of Ohm's LawDrift Current EquationsSemiconductor Band Diagrams with an Electric Field Presen

  15. Buck Converter with Soft-Switching Cells for PV Panel Applications

    Directory of Open Access Journals (Sweden)

    Cheng-Tao Tsai

    2016-03-01

    Full Text Available In power conversion of photovoltaic (PV energy, a hard-switching buck converter always generates some disadvantages. For example, serious electromagnetic interference (EMI, high switching losses, and stresses on an active switch (metal-oxide-semiconductor-field-effect-transistor, MOSFET, and high reverse-recovery losses of a freewheeling diode result in low conversion efficiency. To release these disadvantages, a buck converter with soft-switching cells for PV panel applications is proposed. To create zero-voltage-switching (ZVS features of the active switches, a simple active soft-switching cell with an inductor, a capacitor, and a MOSFET is incorporated into the proposed buck converter. Therefore, the switching losses and stresses of the active switches and EMI can be reduced significantly. To reduce reverse-recovery losses of a freewheeling diode, a simple passive soft-switching cell with a capacitor and two diodes is implemented. To verify the performance and the feasibility of the proposed buck converter with soft-switching cells for PV panel applications, a prototype soft-switching buck converter is built and implemented by using a maximum-power-point-tracking (MPPT method. Simulated and experimental results are presented from a 100 W soft-switching buck converter for PV panel applications.

  16. Tunable radiation emitting semiconductor device

    NARCIS (Netherlands)

    2009-01-01

    A tunable radiation emitting semiconductor device includes at least one elongated structure at least partially fabricated from one or more semiconductor materials exhibiting a bandgap characteristic including one or more energy transitions whose energies correspond to photon energies of light

  17. Modelling switching-time effects in high-frequency power conditioning networks

    Science.gov (United States)

    Owen, H. A.; Sloane, T. H.; Rimer, B. H.; Wilson, T. G.

    1979-01-01

    Power transistor networks which switch large currents in highly inductive environments are beginning to find application in the hundred kilohertz switching frequency range. Recent developments in the fabrication of metal-oxide-semiconductor field-effect transistors in the power device category have enhanced the movement toward higher switching frequencies. Models for switching devices and of the circuits in which they are imbedded are required to properly characterize the mechanisms responsible for turning on and turning off effects. Easily interpreted results in the form of oscilloscope-like plots assist in understanding the effects of parametric studies using topology oriented computer-aided analysis methods.

  18. Final report task order number B239641 between the Regents of the University of California and Institute of Experimental Physics task 2: Switch development

    International Nuclear Information System (INIS)

    Galakhov, I.V.; Gruzin, I.A.; Gudov, S.N.; Kirillov, G.A.; Logutenko, S.L.; Murugov, V.M.; Osin, V.A.; Zolotovskii, V.I.

    1994-01-01

    The LLNL project of the pulsed power system for the National Ignition Facility requires a switch with the following operational parameters: peak current of 400 kA, the transferred charge of 150 C, operating voltage of 25 kV, and reliable operating life of 10,000 shots. A review of high-power switches is given with detailed studies on vacuum switches and semiconductor switches

  19. Simulation of semiconductor devices

    International Nuclear Information System (INIS)

    Oriato, D.

    2001-09-01

    In this thesis a drift diffusion model coupled with self-consistent solutions of Poisson's and Schroedinger's equations, is developed and used to investigate the operation of Gunn diodes and GaN-based LEDs. The model also includes parameters derived from Monte Carlo calculations of the simulated devices. In this way the characteristics of a Monte Carlo approach and of a quantum solver are built into a fast and flexible drift-diffusion model that can be used for testing a large number of heterostructure designs in a time-effective way. The full model and its numerical implementation are described in chapter 2. In chapter 3 the theory of Gunn diodes is presented. A basic model of the dynamics of domain formation and domain transport is described with particular regard to accumulation and dipole domains. Several modes of operation of the Gunn device are described, varying from the resonance mode to the quenched mode. Details about transferred electron devices and negative differential resistance in semiconductor materials are given. In chapter 4 results from the simulation of a simple conventional gunn device confirm the importance of the doping condition at the cathode. Accumulation or dipole domains are achieved respectively with high and low doping densities. The limits of a conventional Gunn diode are explained and solved by introducing the heterostructure Gunn diode. This new design consists of a conventional GaAs transit region coupled with an electron launcher at the cathode, made using an AIGaAs heterostructure step. Simulations show the importance of the insertion of a thin highly-doped layer between the transit region and the electron launcher in order to improve device operation. Chapter 5 is an introduction to Ill-nitrides, in particular GaN and its alloy ln-GaN. We outline the discrepancy in the elastic and piezoelectric parameters found in the literature. Strain, dislocations and piezoelectricity are presented as the main features of a InGaN/GaN system

  20. Physical principles of semiconductor detectors

    International Nuclear Information System (INIS)

    Micek, S.L.

    1979-01-01

    The general properties of semiconductors with respect to the possibilities of their use as the ionization radiation detectors are discussed. Some chosen types of semiconductor junctions and their characteristics are briefly presented. There are also discussed the physical phenomena connected with the formation of barriers in various types of semiconductor counters. Finally, the basic properties of three main types of semiconductor detectors are given. (author)

  1. Metal semiconductor contacts and devices

    CERN Document Server

    Cohen, Simon S; Einspruch, Norman G

    1986-01-01

    VLSI Electronics Microstructure Science, Volume 13: Metal-Semiconductor Contacts and Devices presents the physics, technology, and applications of metal-semiconductor barriers in digital integrated circuits. The emphasis is placed on the interplay among the theory, processing, and characterization techniques in the development of practical metal-semiconductor contacts and devices.This volume contains chapters that are devoted to the discussion of the physics of metal-semiconductor interfaces and its basic phenomena; fabrication procedures; and interface characterization techniques, particularl

  2. Handbook of luminescent semiconductor materials

    CERN Document Server

    Bergman, Leah

    2011-01-01

    Photoluminescence spectroscopy is an important approach for examining the optical interactions in semiconductors and optical devices with the goal of gaining insight into material properties. With contributions from researchers at the forefront of this field, Handbook of Luminescent Semiconductor Materials explores the use of this technique to study semiconductor materials in a variety of applications, including solid-state lighting, solar energy conversion, optical devices, and biological imaging. After introducing basic semiconductor theory and photoluminescence principles, the book focuses

  3. Contraceptive method switching in the United States.

    Science.gov (United States)

    Grady, William R; Billy, John O G; Klepinger, Daniel H

    2002-01-01

    Switching among contraceptive method types is the primary determinant of the prevalence of use of specific contraceptive methods, and it has direct implications for women's ability to avoid unintended pregnancies. Yet, method switching among U.S. women has received little attention from researchers. Data from the 1995 National Survey of Family Growth were used to construct multiple-decrement life tables to explore the gross switching rates of married and unmarried women. Within each group, discrete-time hazard models were estimated to determine how women's characteristics affect their switching behavior. Overall rates of method switching are high among both married and unmarried women (40% and 61%, respectively). Married women's two-year switching rates vary from 30% among women who use the implant, injectable, IUD or other reversible methods to 43% among nonusers, while unmarried women's rates vary from 33% among women who use the implant, injectable or IUD to 70% among nonusers. Multivariate analyses of method switching according to women's characteristics indicate that among married women, women without children are less likely than other women to adopt sterilization or a long-term reversible contraceptive (the implant, injectable or IUD). Older married women have a higher rate than their younger counterparts of switching to sterilization, but are also more likely to continue using no method. Among unmarried women, younger and more highly educated women have high rates of switching to the condom and to dual methods. Women's method switching decisions may be driven primarily by concerns related to level and duration of contraceptive effectiveness, health risks associated with contraceptive use and, among single women, sexually transmitted disease prevention.

  4. Depletion field focusing in semiconductors

    NARCIS (Netherlands)

    Prins, M.W.J.; Gelder, Van A.P.

    1996-01-01

    We calculate the three-dimensional depletion field profile in a semiconductor, for a planar semiconductor material with a spatially varying potential upon the surface, and for a tip-shaped semiconductor with a constant surface potential. The nonuniform electric field gives rise to focusing or

  5. Nonlinear Elasticity of Doped Semiconductors

    Science.gov (United States)

    2017-02-01

    AFRL-RY-WP-TR-2016-0206 NONLINEAR ELASTICITY OF DOPED SEMICONDUCTORS Mark Dykman and Kirill Moskovtsev Michigan State University...2016 4. TITLE AND SUBTITLE NONLINEAR ELASTICITY OF DOPED SEMICONDUCTORS 5a. CONTRACT NUMBER FA8650-16-1-7600 5b. GRANT NUMBER 5c. PROGRAM...vibration amplitude. 15. SUBJECT TERMS semiconductors , microresonators, microelectromechanical 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF

  6. Optical packet switched networks

    DEFF Research Database (Denmark)

    Hansen, Peter Bukhave

    1999-01-01

    Optical packet switched networks are investigated with emphasis on the performance of the packet switch blocks. Initially, the network context of the optical packet switched network is described showing that a packet network will provide transparency, flexibility and bridge the granularity gap...... in interferometric wavelength converters is investigated showing that a 10 Gbit/s 19 4x4 swich blocks can be cascaded at a BER of 10-14. An analytical traffic model enables the calculation of the traffice performance of a WDM packet network. Hereby the importance of WDM and wavelegth conversion in the switch blocks...... is established as a flexible means to reduce the optical buffer, e.g., the number of fibre delay lines for a 16x16 switch block is reduced from 23 to 6 by going from 2 to 8 wavelength channels pr. inlet. Additionally, a component count analysis is carried out to illustrate the trade-offs in the switch block...

  7. Saturated Switching Systems

    CERN Document Server

    Benzaouia, Abdellah

    2012-01-01

    Saturated Switching Systems treats the problem of actuator saturation, inherent in all dynamical systems by using two approaches: positive invariance in which the controller is designed to work within a region of non-saturating linear behaviour; and saturation technique which allows saturation but guarantees asymptotic stability. The results obtained are extended from the linear systems in which they were first developed to switching systems with uncertainties, 2D switching systems, switching systems with Markovian jumping and switching systems of the Takagi-Sugeno type. The text represents a thoroughly referenced distillation of results obtained in this field during the last decade. The selected tool for analysis and design of stabilizing controllers is based on multiple Lyapunov functions and linear matrix inequalities. All the results are illustrated with numerical examples and figures many of them being modelled using MATLAB®. Saturated Switching Systems will be of interest to academic researchers in con...

  8. Semi-conductor rectifiers

    International Nuclear Information System (INIS)

    1981-01-01

    A method is described for treating a semiconductor rectifier, comprising: heating the rectifier to a temperature in the range of 100 0 C to 500 0 C, irradiating the rectifier while maintaining its temperature within the said range, and then annealing the rectifier at a temperature of between 280 0 C and 350 0 C for between two and ten hours. (author)

  9. Semiconductor detector physics

    International Nuclear Information System (INIS)

    Equer, B.

    1987-01-01

    Comprehension of semiconductor detectors follows comprehension of some elements of solid state physics. They are recalled here, limited to the necessary physical principles, that is to say the conductivity. P-n and MIS junctions are discussed in view of their use in detection. Material and structure (MOS, p-n, multilayer, ..) are also reviewed [fr

  10. Effective switching frequency multiplier inverter

    Science.gov (United States)

    Su, Gui-Jia [Oak Ridge, TN; Peng, Fang Z [Okemos, MI

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  11. Magnetic susceptibility of semiconductor melts

    International Nuclear Information System (INIS)

    Kutvitskij, V.A.; Shurygin, P.M.

    1975-01-01

    The temperature dependences chi of various alloys confirm the existence of cluster formations in molten semiconductors, the stability of these formations in melts being considerably affected by the anion nature. The concentrational dependences of the magnetic susceptibility for all the investigated systems exhibit the diamagnetism maxima corresponding to the compound compositions. Heating the melt causes ''smearing'' the maxima, which is related with the cluster structure dissociation. The existence of the maxima concentrational dependence chi corresponding to BiTe and BiSe is found in the isotherms. The non-linear dependence of chi on the composition shows the absence of a single-valued relation between the phase diagram and the chi-diagram for melts

  12. FreeSWITCH Cookbook

    CERN Document Server

    Minessale, Anthony

    2012-01-01

    This is a problem-solution approach to take your FreeSWITCH skills to the next level, where everything is explained in a practical way. If you are a system administrator, hobbyist, or someone who uses FreeSWITCH on a regular basis, this book is for you. Whether you are a FreeSWITCH expert or just getting started, this book will take your skills to the next level.

  13. Elements of magnetic switching

    International Nuclear Information System (INIS)

    Aaland, K.

    1983-01-01

    This chapter describes magnetic switching as a method of connecting a capacitor bank (source) to a load; reviews several successful applications of magnetic switching, and discusses switching transformers, limitations and future possibilities. Some of the inflexibility and especially the high cost of magnetic materials may be overcome with the availability of the new splash cooled ribbons (Metglas). Experience has shown that magnetics works despite shock, radiation or noise interferences

  14. Pemodelan Markov Switching Autoregressive

    OpenAIRE

    Ariyani, Fiqria Devi; Warsito, Budi; Yasin, Hasbi

    2014-01-01

    Transition from depreciation to appreciation of exchange rate is one of regime switching that ignored by classic time series model, such as ARIMA, ARCH, or GARCH. Therefore, economic variables are modeled by Markov Switching Autoregressive (MSAR) which consider the regime switching. MLE is not applicable to parameters estimation because regime is an unobservable variable. So that filtering and smoothing process are applied to see the regime probabilities of observation. Using this model, tran...

  15. Ambipolar organic heterojunction transistors with various p-type semiconductors

    International Nuclear Information System (INIS)

    Shi Jianwu; Wang Haibo; Song De; Tian Hongkun; Geng Yanhou; Yan Donghang

    2008-01-01

    Ambipolar transport has been realized in organic heterojunction transistors with metal phthalocyanines, phenanthrene-based conjugated oligomers as the first semiconductors and copper-hexadecafluoro-phthalocyanine as the second semiconductor. The electron and hole mobilities of ambipolar devices with rod-like molecules were comparable to the corresponding single component devices, while the carrier mobility of ambipolar devices with disk-like molecules was much lower than the corresponding single component devices. The much difference of their device performance was attributed to the roughness of the first semiconductor films, which was original from their distinct growth habits. The flat and continuous films for the first semiconductors layer can lead to a smooth heterojunction interface, and obtained a high device performance for ambipolar organic heterojunction transistors

  16. Stable CW Single-Frequency Operation of Fabry-Perot Laser Diodes by Self-Injection Phase Locking

    Science.gov (United States)

    Duerksen, Gary L.; Krainak, Michael A.

    1999-01-01

    Previously, single-frequency semiconductor laser operation using fiber Bragg gratings has been achieved by two methods: 1) use of the FBG as the output coupler for an anti-reflection-coated semiconductor gain element'; 2) pulsed operation of a gain-switched Fabry-Perot laser diode with FBG-optical and RF-electrical feedback. Here, we demonstrate CW single frequency operation from a non-AR coated Fabry-Perot laser diode using only FBG optical feedback. We coupled a nominal 935 run-wavelength Fabry-Perot laser diode to an ultra narrow band (18 pm) FBG. When tuned by varying its temperature, the laser wavelength is pulled toward the centerline of the Bragg grating, and the spectrum of the laser output is seen to fall into three discrete stability regimes as measured by the side-mode suppression ratio.

  17. New solid state opening switches for repetitive pulsed power technology

    Energy Technology Data Exchange (ETDEWEB)

    Lyubutin, S K; Mesyats, G A; Rukin, S N; Slovikovskii, B G; Turov, A M [Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Electrophysics

    1997-12-31

    In 1991 the authors discovered a semiconductor opening switch (SOS) effect that occurs in p{sup +}-p-n-n{sup +} silicon structures at a current density of up to 60 kA/cm{sup 2}. This effect was used to develop high-power semiconductor opening switches in intermediate inductive storage circuits. The breaking power of the opening switches was as high as 5 GW, the interrupted current being up to 45 kA, reverse voltage up to 1 MV and the current interruption time between 10 and 60 ns. The opening switches were assembled from quantity-produced Russian-made rectifying diodes type SDL with hard recovery characteristic. On the basis of experimental and theoretical investigations of the SOS effect, new SOS diodes were designed and manufactured by the Electrophysical Institute. The paper gives basic parameters of the SOS diodes. The new diodes offer higher values of interrupted current and shorter times of current interruption together with a considerable increase in the energy switching efficiency. The new SOS diodes were used to develop repetitive all-solid-state pulsed generators with an output voltage of up to 250 kV, pulse repetition rate up to 5 kHz, and pulse duration between 10 and 30 ns. (author). 2 tabs., 3 figs., 4 refs.

  18. Tunneling spectroscopy on semiconductors with a low surface state density

    OpenAIRE

    Sommerhalter, Christof; Matthes, Thomas W.; Boneberg, Johannes; Leiderer, Paul; Lux-Steiner, Martha Christina

    1997-01-01

    A detailed study of tunneling spectroscopy concerning semiconductors with a low surface state density is presented. For this purpose, I V curves under dark conditions and under illumination were measured on the (0001) van der Waals surface of a p-type WS2 single crystal, which is known to be free of intrinsic surface states. The measurements are interpreted by an analytical one-dimensional metal-insulator-semiconductor model, which shows that the presence of the finite tunneling current has ...

  19. Semiconductor Laser Tracking Frequency Distance Gauge

    Science.gov (United States)

    Phillips, James D.; Reasenberg, Robert D.

    2009-01-01

    Advanced astronomical missions with greatly enhanced resolution and physics missions of unprecedented accuracy will require a spaceworthy laser distance gauge of substantially improved performance. The Tracking Frequency Gauge (TFG) uses a single beam, locking a laser to the measurement interferometer. We have demonstrated this technique with pm (10(exp -12) m) performance. We report on the version we are now developing based on space-qualifiable, fiber-coupled distributed-feedback semiconductor lasers.

  20. Transient-Switch-Signal Suppressor

    Science.gov (United States)

    Bozeman, Richard J., Jr.

    1995-01-01

    Circuit delays transmission of switch-opening or switch-closing signal until after preset suppression time. Used to prevent transmission of undesired momentary switch signal. Basic mode of operation simple. Beginning of switch signal initiates timing sequence. If switch signal persists after preset suppression time, circuit transmits switch signal to external circuitry. If switch signal no longer present after suppression time, switch signal deemed transient, and circuit does not pass signal on to external circuitry, as though no transient switch signal. Suppression time preset at value large enough to allow for damping of underlying pressure wave or other mechanical transient.