WorldWideScience

Sample records for tolerant semiconductor sensors

  1. 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.

  2. Semiconductor acceleration sensor

    Science.gov (United States)

    Ueyanagi, Katsumichi; Kobayashi, Mitsuo; Goto, Tomoaki

    1996-09-01

    This paper reports a practical semiconductor acceleration sensor especially suited for automotive air bag systems. The acceleration sensor includes four beams arranged in a swastika structure. Two piezoresistors are formed on each beam. These eight piezoresistors constitute a Wheatstone bridge. The swastika structure of the sensing elements, an upper glass plate and a lower glass plate exhibit the squeeze film effect which enhances air dumping, by which the constituent silicon is prevented from breakdown. The present acceleration sensor has the following features. The acceleration force component perpendicular to the sensing direction can be cancelled. The cross-axis sensitivity is less than 3 percent. And, the erroneous offset caused by the differences between the thermal expansion coefficients of the constituent materials can be canceled. The high aspect ratio configuration realized by plasma etching facilitates reducing the dimensions and improving the sensitivity of the acceleration sensor. The present acceleration sensor is 3.9 mm by 3.9 mm in area and 1.2 mm in thickness. The present acceleration sensor can measure from -50 to +50 G with sensitivity of 0.275 mV/G and with non-linearity of less than 1 percent. The acceleration sensor withstands shock of 3000 G.

  3. Electrodes for Semiconductor Gas Sensors

    Science.gov (United States)

    Lee, Sung Pil

    2017-01-01

    The electrodes of semiconductor gas sensors are important in characterizing sensors based on their sensitivity, selectivity, reversibility, response time, and long-term stability. The types and materials of electrodes used for semiconductor gas sensors are analyzed. In addition, the effect of interfacial zones and surface states of electrode–semiconductor interfaces on their characteristics is studied. This study describes that the gas interaction mechanism of the electrode–semiconductor interfaces should take into account the interfacial zone, surface states, image force, and tunneling effect. PMID:28346349

  4. 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

  5. Organic semiconductors in sensor applications

    CERN Document Server

    Malliaras, George; Owens, Róisín

    2008-01-01

    Organic semiconductors offer unique characteristics such as tunability of electronic properties via chemical synthesis, compatibility with mechanically flexible substrates, low-cost manufacturing, and facile integration with chemical and biological functionalities. These characteristics have prompted the application of organic semiconductors and their devices in physical, chemical, and biological sensors. This book covers this rapidly emerging field by discussing both optical and electrical sensor concepts. Novel transducers based on organic light-emitting diodes and organic thin-film transistors, as well as systems-on-a-chip architectures are presented. Functionalization techniques to enhance specificity are outlined, and models for the sensor response are described.

  6. Method of manufacturing a semiconductor sensor device and semiconductor sensor device

    NARCIS (Netherlands)

    2009-01-01

    The invention relates to a method of manufacturing a semiconductor sensor device (10) for sensing a substance comprising a plurality of mutually parallel mesa-shaped semiconductor regions (1) which are formed on a surface of a semiconductor body (11) and which are connected at a first end to a first

  7. Highly Sensitive and Very Stretchable Strain Sensor Based on a Rubbery Semiconductor.

    Science.gov (United States)

    Kim, Hae-Jin; Thukral, Anish; Yu, Cunjiang

    2018-02-07

    There is a growing interest in developing stretchable strain sensors to quantify the large mechanical deformation and strain associated with the activities for a wide range of species, such as humans, machines, and robots. Here, we report a novel stretchable strain sensor entirely in a rubber format by using a solution-processed rubbery semiconductor as the sensing material to achieve high sensitivity, large mechanical strain tolerance, and hysteresis-less and highly linear responses. Specifically, the rubbery semiconductor exploits π-π stacked poly(3-hexylthiophene-2,5-diyl) nanofibrils (P3HT-NFs) percolated in silicone elastomer of poly(dimethylsiloxane) to yield semiconducting nanocomposite with a large mechanical stretchability, although P3HT is a well-known nonstretchable semiconductor. The fabricated strain sensors exhibit reliable and reversible sensing capability, high gauge factor (gauge factor = 32), high linearity (R 2 > 0.996), and low hysteresis (degree of hysteresis wearable smart gloves. Systematic investigations in the materials design and synthesis, sensor fabrication and characterization, and mechanical analysis reveal the key fundamental and application aspects of the highly sensitive and very stretchable strain sensors entirely from rubbers.

  8. The silicon microstrip sensors of the ATLAS semiconductor tracker

    International Nuclear Information System (INIS)

    ATLAS SCT Collaboration; Spieler, Helmuth G.

    2007-01-01

    This paper describes the AC-coupled, single-sided, p-in-n silicon microstrip sensors used in the Semiconductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The sensor requirements, specifications and designs are discussed, together with the qualification and quality assurance procedures adopted for their production. The measured sensor performance is presented, both initially and after irradiation to the fluence anticipated after 10 years of LHC operation. The sensors are now successfully assembled within the detecting modules of the SCT, and the SCT tracker is completed and integrated within the ATLAS Inner Detector. Hamamatsu Photonics Ltd. supplied 92.2percent of the 15,392 installed sensors, with the remainder supplied by CiS

  9. The silicon microstrip sensors of the ATLAS semiconductor tracker

    Energy Technology Data Exchange (ETDEWEB)

    ATLAS SCT Collaboration; Spieler, Helmuth G.

    2007-04-13

    This paper describes the AC-coupled, single-sided, p-in-n silicon microstrip sensors used in the Semiconductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The sensor requirements, specifications and designs are discussed, together with the qualification and quality assurance procedures adopted for their production. The measured sensor performance is presented, both initially and after irradiation to the fluence anticipated after 10 years of LHC operation. The sensors are now successfully assembled within the detecting modules of the SCT, and the SCT tracker is completed and integrated within the ATLAS Inner Detector. Hamamatsu Photonics Ltd. supplied 92.2percent of the 15,392 installed sensors, with the remainder supplied by CiS.

  10. Development of radiation tolerant semiconductor detectors for the Super-LHC

    CERN Document Server

    Moll, M; Al-Ajili, A A; Alfieri, G; Allport, P P; Artuso, M; Assouak, S; Avset, B S; Barabash, L; Barcz, A; Bates, R; Biagi, S F; Bilei, G M; Bisello, D; Blue, A; Blumenau, A; Boisvert, V; Bölla, G; Bondarenko, G B; Borchi, E; Borrello, L; Bortoletto, D; Boscardin, M; Bosisio, L; Bowcock, T J V; Brodbeck, T J; Broz, J; Bruzzi, M; Brzozowski, A; Buda, M; Buhmann, P; Buttar, C; Campabadal, F; Campbell, D; Candelori, A; Casse, G; Cavallini, A; Charron, S; Chilingarov, A; Chren, D; Cindro, V; Collins, P; Coluccia, R; Contarato, D; Coutinho, J; Creanza, D; Cunningham, W; Betta, G F D; Dawson, I; de Boer, Wim; De Palma, M; Demina, R; Dervan, P; Dittongo, S; Dolezal, Z; Dolgolenko, A; Eberlein, T; Eremin, V; Fall, C; Fasolo, F; Fizzotti, F; Fleta, C; Focardi, E; Forton, E; Fretwurst, E; García, C; García-Navarro, J E; Gaubas, E; Genest, M H; Gill, K A; Giolo, K; Glaser, M; Gössling, C; Golovine, V; Sevilla, S G; Gorelov, I; Goss, J; Bates, A G; Grégoire, G; Gregori, P; Grigoriev, E; Grillo, A A; Groza, A; Guskov, J; Haddad, L; Härkönen, J; Hauler, F; Hoeferkamp, M; Honniger, F; Horazdovsky, T; Horisberger, Roland Paul; Horn, M; Houdayer, A; Hourahine, B; Hughes, G; Ilyashenko, Yu S; Irmscher, K; Ivanov, A; Jarasiunas, K; Johansen, K M H; Jones, B K; Jones, R; Joram, C; Jungermann, L; Kalinina, E; Kaminski, P; Karpenko, A; Karpov, A; Kazlauskiene, V; Kazukauskas, V; Khivrich, V; Khomenkov, V; Kierstead, J A; Klaiber Lodewigs, J; Klingenberg, R; Kodys, P; Kohout, Z; Korjenevski, S; Koski, M; Kozlowski, R; Kozodaev, M; Kramberger, G; Krasel, O; Kuznetsov, A; Kwan, S; Lagomarsino, S; Lassila-Perini, K M; Lastovetsky, V F; Latino, G; Lazanu, S; Lazanu, I; Lebedev, A; Lebel, C; Leinonen, K; Leroy, C; Li Z; Lindström, G; Linhart, V; Litovchenko, A P; Litovchenko, P G; Lo Giudice, A; Lozano, M; Luczynski, Z; Luukka, P; Macchiolo, A; Makarenko, L F; Mandic, I; Manfredotti, C; Manna, N; Garcia, S Mi; Marunko, S; Mathieson, K; Melone, J; Menichelli, D; Messineo, A; Metcalfe, J; Miglio, S; Mikuz, M; Miyamoto, J; Monakhov, E; Moscatelli, F; Naoumov, D; Nossarzhevska, E; Nysten, J; Olivero, P; OShea, V; Palviainen, T; Paolini, C; Parkes, C; Passeri, D; Pein, U; Pellegrini, G; Perera, L; Petasecca, M; Piemonte, C; Pignatel, G U; Pinho, N; Pintilie, I; Pintilie, L; Polivtsev, L; Polozov, P; Popa, A; Popule, J; Pospísil, S; Pozza, A; Radicci, V; Rafí, J M; Rando, R; Röder, R; Rohe, T; Ronchin, S; Rott, C; Roy, A; Ruzin, A; Sadrozinski, H F W; Sakalauskas, S; Scaringella, M; Schiavulli, L; Schnetzer, S; Schumm, B; Sciortino, S; Scorzoni, A; Segneri, G; Seidel, S; Seiden, A; Sellberg, G; Sellin, P J; Sentenac, D; Shipsey, I; Sícho, P; Sloan, T; Solar, M; Son, S; Sopko, B; Sopko, V; Spencer, N; Stahl, J; Stolze, D; Stone, R; Storasta, J; Strokan, N; Sudzius, M; Surma, B; Suvorov, A; Svensson, B G; Tipton, P; Tomasek, M; Tsvetkov, A; Tuominen, E; Tuovinen, E; Tuuva, T; Tylchin, M; Uebersee, H; Uher, J; Ullán, M; Vaitkus, J V; Velthuis, J; Verbitskaya, E; Vrba, V; Wagner, G; Wilhelm, I; Worm, S; Wright, V; Wunstorf, R; Yiuri, Y; Zabierowski, P; Zaluzhny, A; Zavrtanik, M; Zen, M; Zhukov, V; Zorzi, N

    2005-01-01

    The envisaged upgrade of the Large Hadron Collider (LHC) at CERN towards the Super-LHC (SLHC) with a 10 times increased luminosity of 10challenges for the tracking detectors of the SLHC experiments. Unprecedented high radiation levels and track densities and a reduced bunch crossing time in the order of 10ns as well as the need for cost effective detectors have called for an intensive R&D program. The CERN RD50 collaboration "Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders" is working on the development of semiconductor sensors matching the requirements of the SLHC. Sensors based on defect engineered silicon like Czochralski, epitaxial and oxygen enriched silicon have been developed. With 3D, Semi-3D and thin detectors new detector concepts have been evaluated and a study on the use of standard and oxygen enriched p-type silicon detectors revealed a promising approach for radiation tolerant cost effective devices. These and other most recent advancements of the RD50 ...

  11. Ways of providing radiation resistance of magnetic field semiconductor sensors

    CERN Document Server

    Bolshakova, I A; Holyaka, R; Matkovskii, A; Moroz, A

    2001-01-01

    Hall magnetic field sensors resistant to hard ionizing irradiation are being developed for operation under the radiation conditions of space and in charged particle accelerators. Radiation resistance of the sensors is first determined by the properties of semiconductor materials of sensitive elements; we have used microcrystals and thin layers of III-V semiconductors. Applying complex doping by rare-earth elements and isovalent impurities in certain proportions, we have obtained magnetic field sensors resistant to irradiation by fast neutrons and gamma-quanta. Tests of their radiation resistance were carried out at IBR-2 at the Joint Institute for Nuclear Research (Dubna). When exposed to neutrons with E=0.1-13 MeV and intensity of 10 sup 1 sup 0 n cm sup - sup 2 s sup - sup 1 , the main parameter of the sensors - their sensitivity to magnetic fields - changes by no more than 0.1% up to fluences of 10 sup 1 sup 4 n cm sup - sup 2. Further improvement of radiation resistance of sensor materials is expected by ...

  12. Hydrogen Sensors Using Nitride-Based Semiconductor Diodes: The Role of Metal/Semiconductor Interfaces

    Directory of Open Access Journals (Sweden)

    Yoshihiro Irokawa

    2011-01-01

    Full Text Available In this paper, I review my recent results in investigating hydrogen sensors using nitride-based semiconductor diodes, focusing on the interaction mechanism of hydrogen with the devices. Firstly, effects of interfacial modification in the devices on hydrogen detection sensitivity are discussed. Surface defects of GaN under Schottky electrodes do not play a critical role in hydrogen sensing characteristics. However, dielectric layers inserted in metal/semiconductor interfaces are found to cause dramatic changes in hydrogen sensing performance, implying that chemical selectivity to hydrogen could be realized. The capacitance-voltage (C-V characteristics reveal that the work function change in the Schottky metal is not responsible mechanism for hydrogen sensitivity. The interface between the metal and the semiconductor plays a critical role in the interaction of hydrogen with semiconductor devises. Secondly, low-frequency C-V characterization is employed to investigate the interaction mechanism of hydrogen with diodes. As a result, it is suggested that the formation of a metal/semiconductor interfacial polarization could be attributed to hydrogen-related dipoles. In addition, using low-frequency C-V characterization leads to clear detection of 100 ppm hydrogen even at room temperature where it is hard to detect hydrogen by using conventional current-voltage (I-V characterization, suggesting that low-frequency C-V method would be effective in detecting very low hydrogen concentrations.

  13. Dissolved hydrogen and oxygen sensors using semiconductor devices

    International Nuclear Information System (INIS)

    Hara, Nobuyoshi; Sugimoto, Katsuhisa

    1995-01-01

    The concentrations of DH and DO in aqueous solution are the factors that determine the equilibrium potential of hydrogen and oxygen electrode reactions, respectively, and are the quantities which directly related to the rates of hydrogen generation type and oxygen consumption type corrosion reactions, therefore, they have the important meaning in the electrochemistry of corrosion. In the hydrogen injection into BWR cooling water, the concentration of hydrogen must be controlled strictly, accordingly DH and DO sensors and electrochemical potential sensors are required. For the chemical sensors used in reactor cooling water, the perfectly solid state sensors made of high corrosion resistance materials, which are small size and withstand high temperature and high pressure, must be developed. The structure and the characteristics of the semiconductor devices used as gas sensors, and the principles of DH and DO sensors are described. If the idea of porous or discontinuous membrane gate is developed, the ion sensor of solid structure with one-body reference electrode may be made. (K.I.)

  14. Development of semiconductor radiation sensors for portable alarm-dosimeter

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Y. K.; Moon, B. S.; Chung, C. E.; Hong, S. B.; Kim, J. Y.; Kim, J. B.; Han, S. H.; Lee, W. G. [Korea Atomic Energy Research Institute, Taejeon (Korea)

    2001-01-01

    We studied Semiconductor Radiation Sensors for Portable Alarm-Dosimeter. We calculated response functions for gamma energy 0.021, 0.122, 0.662, 0.835, 1.2 MeV using EGS4 codes. When we measured at various distance from source to detector, the detection efficiency of Si semiconductor detector was better than that of GM tube. The linear absorption coefficients of steel and aluminum plate were measured. These experimental results of the response of detector for intensity of radiation field coincide to the theoretical expectation. The count value of Si detector was changed with changing thickness of steel as changing threshold voltage of discriminator, and the linear absorption coefficient increased with increasing threshold voltage. Radiation detection efficiency shows difference at each threshold voltage condition. This results coincided to the theoretical simulation. 33 refs., 27 figs., 8 tabs. (Author)

  15. Semiconductor sensor device, diagnostic instrument comprising such a device and method of manufacturing such a device

    NARCIS (Netherlands)

    2010-01-01

    The invention relates to a semiconductor sensor device (10) for sensing a substance comprising at least one mesa- shaped semiconductor region (11) which is formed on a surface of a semiconductor body (12) and which is connected at a first end to a first electrically conducting connection region (13)

  16. Flexible Synthetic Semiconductor Applied in Optoelectronic Organic Sensor

    Directory of Open Access Journals (Sweden)

    Andre F. S. Guedes

    2017-06-01

    Full Text Available The synthesis and application of new nanostructured organic materials, for the development of technology based on organic devices, have taken great interest from the scientific community. The greatest interest in studying organic semiconductor materials has been connected to its already known potential applications, such as: batteries, organic solar cells, flexible organic solar cells, organic light emitting diodes, organic sensors and others. Phototherapy makes use of different radiation sources, and the treatment of hyperbilirubinemia the most common therapeutic intervention occurs in the neonatal period. In this work we developed an organic optoelectronic sensor capable of detecting and determining the radiation dose rate emitted by the radiation source of neonatal phototherapy equipment. The sensors were developed using optically transparent substrate with Nanostructured thin film layers of Poly(9-Vinylcarbazole covered by a layer of Poly(P-Phenylene Vinylene. The samples were characterized by UV-Vis Spectroscopy, Electrical Measurements and SEM. With the results obtained from this study can be developed dosimeters organics to the neonatal phototherapy equipment.

  17. Fault-tolerant system for catastrophic faults in AMR sensors

    NARCIS (Netherlands)

    Zambrano Constantini, A.C.; Kerkhoff, Hans G.

    Anisotropic Magnetoresistance angle sensors are widely used in automotive applications considered to be safety-critical applications. Therefore dependability is an important requirement and fault-tolerant strategies must be used to guarantee the correct operation of the sensors even in case of

  18. Massive Sensor Array Fault Tolerance: Tolerance Mechanism and Fault Injection for Validation

    Directory of Open Access Journals (Sweden)

    Dugan Um

    2010-01-01

    Full Text Available As today's machines become increasingly complex in order to handle intricate tasks, the number of sensors must increase for intelligent operations. Given the large number of sensors, detecting, isolating, and then tolerating faulty sensors is especially important. In this paper, we propose fault tolerance architecture suitable for a massive sensor array often found in highly advanced systems such as autonomous robots. One example is the sensitive skin, a type of massive sensor array. The objective of the sensitive skin is autonomous guidance of machines in unknown environments, requiring elongated operations in a remote site. The entirety of such a system needs to be able to work remotely without human attendance for an extended period of time. To that end, we propose a fault-tolerant architecture whereby component and analytical redundancies are integrated cohesively for effective failure tolerance of a massive array type sensor or sensor system. In addition, we discuss the evaluation results of the proposed tolerance scheme by means of fault injection and validation analysis as a measure of system reliability and performance.

  19. Low Power Operation of Temperature-Modulated Metal Oxide Semiconductor Gas Sensors

    Directory of Open Access Journals (Sweden)

    Javier Burgués

    2018-01-01

    Full Text Available Mobile applications based on gas sensing present new opportunities for low-cost air quality monitoring, safety, and healthcare. Metal oxide semiconductor (MOX gas sensors represent the most prominent technology for integration into portable devices, such as smartphones and wearables. Traditionally, MOX sensors have been continuously powered to increase the stability of the sensing layer. However, continuous power is not feasible in many battery-operated applications due to power consumption limitations or the intended intermittent device operation. This work benchmarks two low-power, duty-cycling, and on-demand modes against the continuous power one. The duty-cycling mode periodically turns the sensors on and off and represents a trade-off between power consumption and stability. On-demand operation achieves the lowest power consumption by powering the sensors only while taking a measurement. Twelve thermally modulated SB-500-12 (FIS Inc. Jacksonville, FL, USA sensors were exposed to low concentrations of carbon monoxide (0–9 ppm with environmental conditions, such as ambient humidity (15–75% relative humidity and temperature (21–27 °C, varying within the indicated ranges. Partial Least Squares (PLS models were built using calibration data, and the prediction error in external validation samples was evaluated during the two weeks following calibration. We found that on-demand operation produced a deformation of the sensor conductance patterns, which led to an increase in the prediction error by almost a factor of 5 as compared to continuous operation (2.2 versus 0.45 ppm. Applying a 10% duty-cycling operation of 10-min periods reduced this prediction error to a factor of 2 (0.9 versus 0.45 ppm. The proposed duty-cycling powering scheme saved up to 90% energy as compared to the continuous operating mode. This low-power mode may be advantageous for applications that do not require continuous and periodic measurements, and which can tolerate

  20. Low Power Operation of Temperature-Modulated Metal Oxide Semiconductor Gas Sensors.

    Science.gov (United States)

    Burgués, Javier; Marco, Santiago

    2018-01-25

    Mobile applications based on gas sensing present new opportunities for low-cost air quality monitoring, safety, and healthcare. Metal oxide semiconductor (MOX) gas sensors represent the most prominent technology for integration into portable devices, such as smartphones and wearables. Traditionally, MOX sensors have been continuously powered to increase the stability of the sensing layer. However, continuous power is not feasible in many battery-operated applications due to power consumption limitations or the intended intermittent device operation. This work benchmarks two low-power, duty-cycling, and on-demand modes against the continuous power one. The duty-cycling mode periodically turns the sensors on and off and represents a trade-off between power consumption and stability. On-demand operation achieves the lowest power consumption by powering the sensors only while taking a measurement. Twelve thermally modulated SB-500-12 (FIS Inc. Jacksonville, FL, USA) sensors were exposed to low concentrations of carbon monoxide (0-9 ppm) with environmental conditions, such as ambient humidity (15-75% relative humidity) and temperature (21-27 °C), varying within the indicated ranges. Partial Least Squares (PLS) models were built using calibration data, and the prediction error in external validation samples was evaluated during the two weeks following calibration. We found that on-demand operation produced a deformation of the sensor conductance patterns, which led to an increase in the prediction error by almost a factor of 5 as compared to continuous operation (2.2 versus 0.45 ppm). Applying a 10% duty-cycling operation of 10-min periods reduced this prediction error to a factor of 2 (0.9 versus 0.45 ppm). The proposed duty-cycling powering scheme saved up to 90% energy as compared to the continuous operating mode. This low-power mode may be advantageous for applications that do not require continuous and periodic measurements, and which can tolerate slightly higher

  1. Development of integrated semiconductor optical sensors for functional brain imaging

    Science.gov (United States)

    Lee, Thomas T.

    Optical imaging of neural activity is a widely accepted technique for imaging brain function in the field of neuroscience research, and has been used to study the cerebral cortex in vivo for over two decades. Maps of brain activity are obtained by monitoring intensity changes in back-scattered light, called Intrinsic Optical Signals (IOS), that correspond to fluctuations in blood oxygenation and volume associated with neural activity. Current imaging systems typically employ bench-top equipment including lamps and CCD cameras to study animals using visible light. Such systems require the use of anesthetized or immobilized subjects with craniotomies, which imposes limitations on the behavioral range and duration of studies. The ultimate goal of this work is to overcome these limitations by developing a single-chip semiconductor sensor using arrays of sources and detectors operating at near-infrared (NIR) wavelengths. A single-chip implementation, combined with wireless telemetry, will eliminate the need for immobilization or anesthesia of subjects and allow in vivo studies of free behavior. NIR light offers additional advantages because it experiences less absorption in animal tissue than visible light, which allows for imaging through superficial tissues. This, in turn, reduces or eliminates the need for traumatic surgery and enables long-term brain-mapping studies in freely-behaving animals. This dissertation concentrates on key engineering challenges of implementing the sensor. This work shows the feasibility of using a GaAs-based array of vertical-cavity surface emitting lasers (VCSELs) and PIN photodiodes for IOS imaging. I begin with in-vivo studies of IOS imaging through the skull in mice, and use these results along with computer simulations to establish minimum performance requirements for light sources and detectors. I also evaluate the performance of a current commercial VCSEL for IOS imaging, and conclude with a proposed prototype sensor.

  2. Sensor development at the semiconductor laboratory of the Max-Planck-Society

    Science.gov (United States)

    Bähr, A.; Lechner, P.; Ninkovic, J.

    2017-12-01

    For more than twenty years the semiconductor laboratory of the Max-Planck Society (MPG-HLL) is developing high-performing, specialised, scientific silicon sensors including the integration of amplifying electronics on the sensor chip. This paper summarises the actual status of these devices like pnCCDs and DePFET Active Pixel Sensors and their applications.

  3. 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.

  4. An Ultrasensitive Organic Semiconductor NO2 Sensor Based on Crystalline TIPS-Pentacene Films.

    Science.gov (United States)

    Wang, Zi; Huang, Lizhen; Zhu, Xiaofei; Zhou, Xu; Chi, Lifeng

    2017-10-01

    Organic semiconductor gas sensor is one of the promising candidates of room temperature operated gas sensors with high selectivity. However, for a long time the performance of organic semiconductor sensors, especially for the detection of oxidizing gases, is far behind that of the traditional metal oxide gas sensors. Although intensive attempts have been made to address the problem, the performance and the understanding of the sensing mechanism are still far from sufficient. Herein, an ultrasensitive organic semiconductor NO 2 sensor based on 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS-petacene) is reported. The device achieves a sensitivity over 1000%/ppm and fast response/recovery, together with a low limit of detection (LOD) of 20 ppb, all of which reach the level of metal oxide sensors. After a comprehensive analysis on the morphology and electrical properties of the organic films, it is revealed that the ultrahigh performance is largely related to the film charge transport ability, which was less concerned in the studies previously. And the combination of efficient charge transport and low original charge carrier concentration is demonstrated to be an effective access to obtain high performance organic semiconductor gas sensors. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Estimation of the limit of detection in semiconductor gas sensors through linearized calibration models.

    Science.gov (United States)

    Burgués, Javier; Jiménez-Soto, Juan Manuel; Marco, Santiago

    2018-07-12

    The limit of detection (LOD) is a key figure of merit in chemical sensing. However, the estimation of this figure of merit is hindered by the non-linear calibration curve characteristic of semiconductor gas sensor technologies such as, metal oxide (MOX), gasFETs or thermoelectric sensors. Additionally, chemical sensors suffer from cross-sensitivities and temporal stability problems. The application of the International Union of Pure and Applied Chemistry (IUPAC) recommendations for univariate LOD estimation in non-linear semiconductor gas sensors is not straightforward due to the strong statistical requirements of the IUPAC methodology (linearity, homoscedasticity, normality). Here, we propose a methodological approach to LOD estimation through linearized calibration models. As an example, the methodology is applied to the detection of low concentrations of carbon monoxide using MOX gas sensors in a scenario where the main source of error is the presence of uncontrolled levels of humidity. Copyright © 2018 Elsevier B.V. All rights reserved.

  6. A Fault Tolerance Mechanism for On-Road Sensor Networks

    Directory of Open Access Journals (Sweden)

    Lei Feng

    2016-12-01

    Full Text Available On-Road Sensor Networks (ORSNs play an important role in capturing traffic flow data for predicting short-term traffic patterns, driving assistance and self-driving vehicles. However, this kind of network is prone to large-scale communication failure if a few sensors physically fail. In this paper, to ensure that the network works normally, an effective fault-tolerance mechanism for ORSNs which mainly consists of backup on-road sensor deployment, redundant cluster head deployment and an adaptive failure detection and recovery method is proposed. Firstly, based on the N − x principle and the sensors’ failure rate, this paper formulates the backup sensor deployment problem in the form of a two-objective optimization, which explains the trade-off between the cost and fault resumption. In consideration of improving the network resilience further, this paper introduces a redundant cluster head deployment model according to the coverage constraint. Then a common solving method combining integer-continuing and sequential quadratic programming is explored to determine the optimal location of these two deployment problems. Moreover, an Adaptive Detection and Resume (ADR protocol is deigned to recover the system communication through route and cluster adjustment if there is a backup on-road sensor mismatch. The final experiments show that our proposed mechanism can achieve an average 90% recovery rate and reduce the average number of failed sensors at most by 35.7%.

  7. Semiconductor device-based sensors for gas, chemical, and biomedical applications

    CERN Document Server

    Ren, Fan

    2011-01-01

    Sales of U.S. chemical sensors represent the largest segment of the multi-billion-dollar global sensor market, which includes instruments for chemical detection in gases and liquids, biosensors, and medical sensors. Although silicon-based devices have dominated the field, they are limited by their general inability to operate in harsh environments faced with factors such as high temperature and pressure. Exploring how and why these instruments have become a major player, Semiconductor Device-Based Sensors for Gas, Chemical, and Biomedical Applications presents the latest research, including or

  8. Bacteria inside semiconductors as potential sensor elements: biochip progress.

    Science.gov (United States)

    Sah, Vasu R; Baier, Robert E

    2014-06-24

    It was discovered at the beginning of this Century that living bacteria-and specifically the extremophile Pseudomonas syzgii-could be captured inside growing crystals of pure water-corroding semiconductors-specifically germanium-and thereby initiated pursuit of truly functional "biochip-based" biosensors. This observation was first made at the inside ultraviolet-illuminated walls of ultrapure water-flowing semiconductor fabrication facilities (fabs) and has since been, not as perfectly, replicated in simpler flow cell systems for chip manufacture, described here. Recognizing the potential importance of these adducts as optical switches, for example, or probes of metabolic events, the influences of the fabs and their components on the crystal nucleation and growth phenomena now identified are reviewed and discussed with regard to further research needs. For example, optical beams of current photonic circuits can be more easily modulated by integral embedded cells into electrical signals on semiconductors. Such research responds to a recently published Grand Challenge in ceramic science, designing and synthesizing oxide electronics, surfaces, interfaces and nanoscale structures that can be tuned by biological stimuli, to reveal phenomena not otherwise possible with conventional semiconductor electronics. This short review addresses only the fabrication facilities' features at the time of first production of these potential biochips.

  9. Semiconductor sensor for optically measuring polarization rotation of optical wavefronts using rare earth iron garnets

    Science.gov (United States)

    Duncan, Paul G.

    2002-01-01

    Described are the design of a rare earth iron garnet sensor element, optical methods of interrogating the sensor element, methods of coupling the optical sensor element to a waveguide, and an optical and electrical processing system for monitoring the polarization rotation of a linearly polarized wavefront undergoing external modulation due to magnetic field or electrical current fluctuation. The sensor element uses the Faraday effect, an intrinsic property of certain rare-earth iron garnet materials, to rotate the polarization state of light in the presence of a magnetic field. The sensor element may be coated with a thin-film mirror to effectively double the optical path length, providing twice the sensitivity for a given field strength or temperature change. A semiconductor sensor system using a rare earth iron garnet sensor element is described.

  10. Laser Doppler perfusion imaging with a complimentary metal oxide semiconductor image sensor

    NARCIS (Netherlands)

    Serov, Alexander; Steenbergen, Wiendelt; de Mul, F.F.M.

    2002-01-01

    We utilized a complimentary metal oxide semiconductor video camera for fast f low imaging with the laser Doppler technique. A single sensor is used for both observation of the area of interest and measurements of the interference signal caused by dynamic light scattering from moving particles inside

  11. Semiconductor Metal Oxide Sensors in Water and Water Based Biological Systems

    Directory of Open Access Journals (Sweden)

    Marina V. Strobkova

    2003-10-01

    Full Text Available The results of implementation of In2O3-based semiconductor sensors for oxygen concentration evaluation in water and the LB-nutrient media (15.5 g/l Luria Broth Base, Miller (Sigma, Lot-1900 and NaCl without bacteria and with E.coli bacteria before and after UV-irradiation are presented.

  12. Fault Tolerance in ZigBee Wireless Sensor Networks

    Science.gov (United States)

    Alena, Richard; Gilstrap, Ray; Baldwin, Jarren; Stone, Thom; Wilson, Pete

    2011-01-01

    Wireless sensor networks (WSN) based on the IEEE 802.15.4 Personal Area Network standard are finding increasing use in the home automation and emerging smart energy markets. The network and application layers, based on the ZigBee 2007 PRO Standard, provide a convenient framework for component-based software that supports customer solutions from multiple vendors. This technology is supported by System-on-a-Chip solutions, resulting in extremely small and low-power nodes. The Wireless Connections in Space Project addresses the aerospace flight domain for both flight-critical and non-critical avionics. WSNs provide the inherent fault tolerance required for aerospace applications utilizing such technology. The team from Ames Research Center has developed techniques for assessing the fault tolerance of ZigBee WSNs challenged by radio frequency (RF) interference or WSN node failure.

  13. Bacteria Inside Semiconductors as Potential Sensor Elements: Biochip Progress

    Directory of Open Access Journals (Sweden)

    Vasu R. Sah

    2014-06-01

    Full Text Available It was discovered at the beginning of this Century that living bacteria—and specifically the extremophile Pseudomonas syzgii—could be captured inside growing crystals of pure water-corroding semiconductors—specifically germanium—and thereby initiated pursuit of truly functional “biochip-based” biosensors. This observation was first made at the inside ultraviolet-illuminated walls of ultrapure water-flowing semiconductor fabrication facilities (fabs and has since been, not as perfectly, replicated in simpler flow cell systems for chip manufacture, described here. Recognizing the potential importance of these adducts as optical switches, for example, or probes of metabolic events, the influences of the fabs and their components on the crystal nucleation and growth phenomena now identified are reviewed and discussed with regard to further research needs. For example, optical beams of current photonic circuits can be more easily modulated by integral embedded cells into electrical signals on semiconductors. Such research responds to a recently published Grand Challenge in ceramic science, designing and synthesizing oxide electronics, surfaces, interfaces and nanoscale structures that can be tuned by biological stimuli, to reveal phenomena not otherwise possible with conventional semiconductor electronics. This short review addresses only the fabrication facilities’ features at the time of first production of these potential biochips.

  14. Fault-tolerant Sensor Fusion for Marine Navigation

    DEFF Research Database (Denmark)

    Blanke, Mogens

    2006-01-01

    Reliability of navigation data are critical for steering and manoeuvring control, and in particular so at high speed or in critical phases of a mission. Should faults occur, faulty instruments need be autonomously isolated and faulty information discarded. This paper designs a navigation solution...... where essential navigation information is provided even with multiple faults in instrumentation. The paper proposes a provable correct implementation through auto-generated state-event logics in a supervisory part of the algorithms. Test results from naval vessels document the performance and shows...... events where the fault-tolerant sensor fusion provided uninterrupted navigation data despite temporal instrument defects...

  15. Energy efficiency enhancements for semiconductors, communications, sensors and software achieved in cool silicon cluster project

    Science.gov (United States)

    Ellinger, Frank; Mikolajick, Thomas; Fettweis, Gerhard; Hentschel, Dieter; Kolodinski, Sabine; Warnecke, Helmut; Reppe, Thomas; Tzschoppe, Christoph; Dohl, Jan; Carta, Corrado; Fritsche, David; Tretter, Gregor; Wiatr, Maciej; Detlef Kronholz, Stefan; Mikalo, Ricardo Pablo; Heinrich, Harald; Paulo, Robert; Wolf, Robert; Hübner, Johannes; Waltsgott, Johannes; Meißner, Klaus; Richter, Robert; Michler, Oliver; Bausinger, Markus; Mehlich, Heiko; Hahmann, Martin; Möller, Henning; Wiemer, Maik; Holland, Hans-Jürgen; Gärtner, Roberto; Schubert, Stefan; Richter, Alexander; Strobel, Axel; Fehske, Albrecht; Cech, Sebastian; Aßmann, Uwe; Pawlak, Andreas; Schröter, Michael; Finger, Wolfgang; Schumann, Stefan; Höppner, Sebastian; Walter, Dennis; Eisenreich, Holger; Schüffny, René

    2013-07-01

    An overview about the German cluster project Cool Silicon aiming at increasing the energy efficiency for semiconductors, communications, sensors and software is presented. Examples for achievements are: 1000 times reduced gate leakage in transistors using high-fc (HKMG) materials compared to conventional poly-gate (SiON) devices at the same technology node; 700 V transistors integrated in standard 0.35 μm CMOS; solar cell efficiencies above 19% at cars Contribution to the Topical Issue “International Semiconductor Conference Dresden-Grenoble - ISCDG 2012”, Edited by Gérard Ghibaudo, Francis Balestra and Simon Deleonibus.

  16. Semiconductor-based electret sensors for sound and pressure

    NARCIS (Netherlands)

    Voorthuyzen, J.A.; Bergveld, Piet; Sprenkels, A.J.

    1989-01-01

    The theory and experimental results for integrated electret-based silicon sensors for the detection of sound and pressure are presented. A silicon electret microphone for use in hearing-aids is described. It has an experimentally determined sensitivity of 19 mV/Pa in the frequency range of 50 Hz to

  17. The Silicon Microstrip Sensors of the ATLAS SemiConductor Tracker

    CERN Document Server

    Ahmad, A; Allport, P P; Alonso, J; Andricek, L; Apsimon, R J; Barr, A J; Bates, R L; Beck, G A; Bell, P J; Belymam, A; Benes, J; Berg, C M; Bernabeu, J; Bethke, S; Bingefors, N; Bizzell, J P; Bohm, J; Brenner, R; Brodbeck, T J; Bruckman De Renstrom, P; Buttar, C M; Campbell, D; Carpentieri, C; Carter, A A; Carter, J R; Charlton, D G; Casse, G-L; Chilingarov, A; Cindro, V; Ciocio, A; Civera, J V; Clark, A G; Colijn, A-P; Costa, M J; Dabrowski, W; Danielsen, K M; Dawson, I; Demirkoz, B; Dervan, P; Dolezal, Z; Dorholt, O; Duerdoth, I P; Dwuznik, M; Eckert, S; Ekelöf, T; Eklund, L; Escobar, C; Fasching, D; Feld, L; Ferguson, D P S; Ferrere, D; Fortin, R; Foster, J M; Fox, H; French, R; Fromant, B P; Fujita, K; Fuster, J; Gadomski, S; Gallop, B J; Garcia, C; Garcia-Navarro, J E; Gibson, M D; Gonzalez, S; Gonzalez-Sevilla, S; Goodrick, M J; Gornicki, E; Green, C; Greenall, A; Grigson, C; Grillo, A A; Grosse-Knetter, J; Haber, C; Handa, T; Hara, K; Harper, R S; Hartjes, F G; Hashizaki, T; Hauff, D; Hessey, N P; Hill, J C; Hollins, T I; Holt, S; Horazdovsky, T; Hornung, M; Hovland, K M; Hughes, G; Huse, T; Ikegami, Y; Iwata, Y; Jackson, J N; Jakobs, K; Jared, R C; Johansen, L G; Jones, R W L; Jones, T J; de Jong, P; Joseph, J; Jovanovic, P; Kaplon, J; Kato, Y; Ketterer, C; Kindervaag, I M; Kodys, P; Koffeman, E; Kohriki, T; Kohout, Z; Kondo, T; Koperny, S; van der Kraaij, E; Kral, V; Kramberger, G; Kudlaty, J; Lacasta, C; Limper, M; Linhart, V; Llosa, G; Lozano, M; Ludwig, I; Ludwig, J; Lutz, G; Macpherson, A; McMahon, S J; Macina, D; Magrath, C A; Malecki, P; Mandic, I; Marti-Garcia, S; Matsuo, T; Meinhardt, J; Mellado, B; Mercer, I J; Mikestikova, M; Mikuz, M; Minano, M; Mistry, J; Mitsou, V; Modesto, P; Mohn, B; Molloy, S D; Moorhead, G; Moraes, A; Morgan, D; Morone, M C; Morris, J; Moser, H-G; Moszczynski, A; Muijs, A J M; Nagai, K; Nakamura, Y; Nakano, I; Nicholson, R; Niinikoski, T; Nisius, R; Ohsugi, T; O'Shea, V; Oye, O K; Parzefall, U; Pater, J R; Pernegger, H; Phillips, P W; Posisil, S; Ratoff, P N; Reznicek, P; Richardson, J D; Richter, R H; Robinson, D; Roe, S; Ruggiero, G; Runge, K; Sadrozinski, H F W; Sandaker, H; Schieck, J; Seiden, A; Shinma, S; Siegrist, J; Sloan, T; Smith, N A; Snow, S W; Solar, M; Solberg, A; Sopko, B; Sospedra, L; Spieler, H; Stanecka, E; Stapnes, S; Stastny, J; Stelzer, F; Stradling, A; Stugu, B; Takashima, R; Tanaka, R; Taylor, G; Terada, S; Thompson, R J; Titov, M; Tomeda, Y; Tovey, D R; Turala, M; Turner, P R; Tyndel, M; Ullan, M; Unno, Y; Vickey, T; Vos, M; Wallny, R; Weilhammer, P; Wells, P S; Wilson, J A; Wolter, M; Wormald, M; Wu, S L; Yamashita, T; Zontar, D; Zsenei, A

    2007-01-01

    This paper describes the AC-coupled, single-sided, p-in-n silicon microstrip sensors used in the SemiConductor Tracker (SCT) of the ATLAS experiment at the CERN Large Hadron Collider (LHC). The sensor requirements, specifications and designs are discussed, together with the qualification and quality assurance procedures adopted for their production. The measured sensor performance is presented, both initially and after irradiation to the fluence anticipated after 10 years of LHC operation. The sensors are now successfully assembled within the detecting modules of the SCT, and the SCT tracker is completed and integrated within the ATLAS Inner Detector. Hamamatsu Photonics Ltd supplied 92.2% of the 15,392 installed sensors, with the remainder supplied by CiS.

  18. Semiconductor Sensors for Studying the Heterogeneous Destruction of Ozone at Low Concentrations

    Science.gov (United States)

    Obvintseva, L. A.; Sharova, T. B.; Avetisov, A. K.; Sukhareva, I. P.

    2018-06-01

    Prospects for the use of semiconductor resistive sensors in studies of the heterogeneous destruction of ozone at low concentrations (5-400 μg/m3) were shown. The influence of various factors (sensor temperature, gas flow rate, ozone concentration) on the results of ozone concentration measurements with sensors of various types was studied. Methods for forming a sensitive layer of In2O3(3% Fe2O3) sensors with specified parameters of calibration curves were proposed. The optimum conditions for the operation of sensors in a flow mode were formulated. The results of the study of heterogeneous destruction of ozone on microfiber polymer and natural disperse (sand, coals) materials obtained by the developed method were presented.

  19. On-chip growth of semiconductor metal oxide nanowires for gas sensors: A review

    Directory of Open Access Journals (Sweden)

    Chu Manh Hung

    2017-09-01

    Full Text Available Semiconductor metal oxide nanowires (SMO-NWs show great potential for novel gas sensor applications because of their distinct properties, such as a high surface area to volume aspect ratio, high crystallinity and perfect pathway for electron transfer (length of NW. SMO-NW sensors can be configured as resistors or field-effect transistors for gas detection and different configurations, such as a single NW, multiple NWs, and networked NW films, have been established. Surface-functionalizing NWs with catalyst elements and self-heating NWs provide additional advantages for highly selective and low-power consumption gas sensors. However, an appropriate design of SMO-NWs is of practical importance in enhancing the gas-sensing performance of SMO-NW sensors. The on-chip growth of SMO-NWs possesses many advantages which can thus be effectively used for the large-scale fabrication of SMO-NW sensors with improved gas response and stability. This review aims to provide up-to-date information on the on-chip fabrication of SnO2, ZnO, WO3, CuO, and other SMO-NW sensors. It also discusses a variety of promising approaches that help advance the on-chip fabrication of SMO-NW-based gas sensors and other NW-based devices.

  20. Evaluation of semiconductor gas sensor system for ethanol determination during fermentation processes

    Energy Technology Data Exchange (ETDEWEB)

    Picque, D; Corrieu, G

    1988-10-01

    Using commercial gas sensitive semi-conductors, an ethanol sensor has been constructed which operates by direct immersion in fermentation media. The calibration range of 0.1 to 10 or 13 % depending on the component. However, they are very often subjected to considerable drift (in the same case up to 10 %/h of the measured value). The electrical resistance of component may vary by a factor of 1 to 5 for a well-defined ethanol concentration. The effects of temperature changes in fermentation media are easily compensated. Other volatile compounds (methanol, ammonia,...) substantially affect component responses. Thus, all work on sensors requires careful calibration. Wine fermentation processes can be monitored satisfactorily, providing the sensor is recalibrated about every six hours.

  1. Improving the Performance of Semiconductor Sensor Devices Using Surface Functionalization

    Science.gov (United States)

    Rohrbaugh, Nathaniel W.

    As production and understanding of III-nitride growth has progressed, this class of material has been used for its semiconducting properties in the fields of computer processing, microelectronics, and LEDs. As understanding of materials properties has advanced, devices were fabricated to be sensitive to environmental surroundings such as pH, gas, or ionic concentration. Simultaneously the world of pharmaceuticals and environmental science has come to the age where the use of wearable devices and active environmental sensing can not only help us learn more about our surroundings, but help save lives. At the crossroads of these two fields work has been done in marrying the high stability and electrical properties of the III-nitrides with the needs of a growing sensor field for various environments and stimuli. Device architecture can only get one so far, and thus the need for well understood surface functionalization techniques has arisen in the field of III-nitride environmental sensing. Many existing schemes for functionalization involve chemistries that may be unfriendly to a biological environment, unstable in solution, or expensive to produce. One possible solution to these issues is the work presented here, which highlights a surface modification scheme utilizing phosphonic acid based chemistry and biomolecular attachment. This dissertation presents a set of studies and experiments quantifying and analyzing the response behaviors of AlGaN/GaN field effect transistor (FET) devices via their interfacial electronic properties. Additional investigation was done on the modification of these surfaces, effects of stressful environmental conditions, and the utility of the phosphonic acid surface treatments. Signals of AlGaN/GaN FETs were measured as IDrain values and in the earliest study an average signal increase of 96.43% was observed when surfaces were incubated in a solution of a known recognition peptide sequence (SVSVGMKPSPRP). This work showed that even without

  2. Influence of semiconductor/metal interface geometry in an EMR sensor

    KAUST Repository

    Sun, Jian

    2013-02-01

    The extraordinary magnetoresistance (EMR) is well known to be strongly dependent on geometric parameters. While the influence of the aspect ratios of the metal and semiconductor areas has been thoroughly investigated, the geometry of the semiconductor/metal interface has been neglected so far. However, from a fabrication point of view, this part plays a crucial role. In this paper, the performance of a bar-type hybrid EMR sensor is investigated by means of finite element method and experiments with respect to the hybrid interface geometry. A 3-D model has been developed, which simulates the EMR effect in case of fields in different directions. The semiconductor/metal interface has been investigated in terms of different layer thicknesses and overlaps. The results show that those parameters can cause a change in the output sensitivity of 2%-10%. In order to maintain a high sensitivity and keep the fabrication relatively simple and at low cost, a device with a thin metal shunt having a large overlap on the top of the semiconductor bar would provide the best solution. © 2001-2012 IEEE.

  3. LaF3 thin films as chemically sensitive material for semiconductor sensors

    International Nuclear Information System (INIS)

    Szeponik, J.; Moritz, W.; Sellam, F.

    1991-01-01

    A new kind of semiconductor based fluoride sensor was prepared by growing thin polycrystalline LaF 3 films directly on silicon substrates using vacuum vapour deposition technique. The EICS (Electrolyte Ion Conductor Semiconductor) structure was investigated by means of impedance spectroscopy, C-V measurements and exchange measurements with labeled ions ( 18 F). Whereas charge and potential conditions at the LaF 3 /electrolyte interface are governed by the fast fluoride exchange the LaF 3 bulk and the blocked Si/LaF 3 interface determine the electrical behavior. Although the Si/LaF 3 contact is not reversible the potential stability of the EICS structure is surprisingly high. Additional results at epitaxial LaF 3 layers, prepared by MBE, were taken into account for comparision with those at polycrystalline layers. (orig.)

  4. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics

    Directory of Open Access Journals (Sweden)

    Jianqiao Liu

    2017-08-01

    Full Text Available The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  5. Inhomogeneous Oxygen Vacancy Distribution in Semiconductor Gas Sensors: Formation, Migration and Determination on Gas Sensing Characteristics.

    Science.gov (United States)

    Liu, Jianqiao; Gao, Yinglin; Wu, Xu; Jin, Guohua; Zhai, Zhaoxia; Liu, Huan

    2017-08-10

    The density of oxygen vacancies in semiconductor gas sensors was often assumed to be identical throughout the grain in the numerical discussion of the gas-sensing mechanism of the devices. In contrast, the actual devices had grains with inhomogeneous distribution of oxygen vacancy under non-ideal conditions. This conflict between reality and discussion drove us to study the formation and migration of the oxygen defects in semiconductor grains. A model of the gradient-distributed oxygen vacancy was proposed based on the effects of cooling rate and re-annealing on semiconductive thin films. The model established the diffusion equations of oxygen vacancy according to the defect kinetics of diffusion and exclusion. We described that the steady-state and transient-state oxygen vacancy distributions, which were used to calculate the gas-sensing characteristics of the sensor resistance and response to reducing gases under two different conditions. The gradient-distributed oxygen vacancy model had the applications in simulating the sensor performances, such as the power law, the grain size effect and the effect of depletion layer width.

  6. Semiconductor Sensors Application for Definition of Factor of Ozone Heterogeneous Destruction on Teflon Surface

    Directory of Open Access Journals (Sweden)

    Nataliya V. Finogenova

    2003-12-01

    Full Text Available In our paper we present the results of our research, which was carried out by means of semiconductor sensor techniques (SCS, which allowed evaluating heterogeneous death-rate of ozone (γ Teflon surface. When ozone concentration is near to Ambient Air Standard value, γ is assessed to be equal to 6,57*10-7. High technique response provide possibility to determine ozone contents in the air media and the percentage of ozone, decomposed on the communication surfaces and on the surfaces of installation in the low concentration range (1–100 ppb.

  7. Methods and apparatuses for detection of radiation with semiconductor image sensors

    Science.gov (United States)

    Cogliati, Joshua Joseph

    2018-04-10

    A semiconductor image sensor is repeatedly exposed to high-energy photons while a visible light obstructer is in place to block visible light from impinging on the sensor to generate a set of images from the exposures. A composite image is generated from the set of images with common noise substantially removed so the composite image includes image information corresponding to radiated pixels that absorbed at least some energy from the high-energy photons. The composite image is processed to determine a set of bright points in the composite image, each bright point being above a first threshold. The set of bright points is processed to identify lines with two or more bright points that include pixels therebetween that are above a second threshold and identify a presence of the high-energy particles responsive to a number of lines.

  8. DNA-decorated carbon-nanotube-based chemical sensors on complementary metal oxide semiconductor circuitry

    International Nuclear Information System (INIS)

    Chen, Chia-Ling; Yang, Chih-Feng; Dokmeci, Mehmet R; Agarwal, Vinay; Sonkusale, Sameer; Kim, Taehoon; Busnaina, Ahmed; Chen, Michelle

    2010-01-01

    We present integration of single-stranded DNA (ss-DNA)-decorated single-walled carbon nanotubes (SWNTs) onto complementary metal oxide semiconductor (CMOS) circuitry as nanoscale chemical sensors. SWNTs were assembled onto CMOS circuitry via a low voltage dielectrophoretic (DEP) process. Besides, bare SWNTs are reported to be sensitive to various chemicals, and functionalization of SWNTs with biomolecular complexes further enhances the sensing specificity and sensitivity. After decorating ss-DNA on SWNTs, we have found that the sensing response of the gas sensor was enhanced (up to ∼ 300% and ∼ 250% for methanol vapor and isopropanol alcohol vapor, respectively) compared with bare SWNTs. The SWNTs coupled with ss-DNA and their integration on CMOS circuitry demonstrates a step towards realizing ultra-sensitive electronic nose applications.

  9. Fault-tolerant control for current sensors of doubly fed induction generators based on an improved fault detection method

    DEFF Research Database (Denmark)

    Li, Hui; Yang, Chao; Hu, Yaogang

    2014-01-01

    Fault-tolerant control of current sensors is studied in this paper to improve the reliability of a doubly fed induction generator (DFIG). A fault-tolerant control system of current sensors is presented for the DFIG, which consists of a new current observer and an improved current sensor fault...... detection algorithm, and fault-tolerant control system are investigated by simulation. The results indicate that the outputs of the observer and the sensor are highly coherent. The fault detection algorithm can efficiently detect both soft and hard faults in current sensors, and the fault-tolerant control...

  10. Towards a contamination-tolerant EUV power sensor

    NARCIS (Netherlands)

    Veldhoven, J. van; Putten, M. van; Nieuwkoop, E.; Huijser, T.; Maas, D.J.

    2015-01-01

    In EUV Lithography short-, mid- and long-term control over in-band EUV power is needed for high-yield IC production. Existing sensors can be unstable over time due to contamination and/or degradation. TNO goal: to conceive a stable EUV power sensor. Sensitive to in-band EUV, negligible degradation,

  11. Finite Element Analysis of Film Stack Architecture for Complementary Metal-Oxide-Semiconductor Image Sensors.

    Science.gov (United States)

    Wu, Kuo-Tsai; Hwang, Sheng-Jye; Lee, Huei-Huang

    2017-05-02

    Image sensors are the core components of computer, communication, and consumer electronic products. Complementary metal oxide semiconductor (CMOS) image sensors have become the mainstay of image-sensing developments, but are prone to leakage current. In this study, we simulate the CMOS image sensor (CIS) film stacking process by finite element analysis. To elucidate the relationship between the leakage current and stack architecture, we compare the simulated and measured leakage currents in the elements. Based on the analysis results, we further improve the performance by optimizing the architecture of the film stacks or changing the thin-film material. The material parameters are then corrected to improve the accuracy of the simulation results. The simulated and experimental results confirm a positive correlation between measured leakage current and stress. This trend is attributed to the structural defects induced by high stress, which generate leakage. Using this relationship, we can change the structure of the thin-film stack to reduce the leakage current and thereby improve the component life and reliability of the CIS components.

  12. Highly Sensitive Flexible Pressure Sensors Based on Printed Organic Transistors with Centro-Apically Self-Organized Organic Semiconductor Microstructures.

    Science.gov (United States)

    Yeo, So Young; Park, Sangsik; Yi, Yeon Jin; Kim, Do Hwan; Lim, Jung Ah

    2017-12-13

    A highly sensitive pressure sensor based on printed organic transistors with three-dimensionally self-organized organic semiconductor microstructures (3D OSCs) was demonstrated. A unique organic transistor with semiconductor channels positioned at the highest summit of printed cylindrical microstructures was achieved simply by printing an organic semiconductor and polymer blend on the plastic substrate without the use of additional etching or replication processes. A combination of the printed organic semiconductor microstructure and an elastomeric top-gate dielectric resulted in a highly sensitive organic field-effect transistor (FET) pressure sensor with a high pressure sensitivity of 1.07 kPa -1 and a rapid response time of <20 ms with a high reliability over 1000 cycles. The flexibility and high performance of the 3D OSC FET pressure sensor were exploited in the successful application of our sensors to real-time monitoring of the radial artery pulse, which is useful for healthcare monitoring, and to touch sensing in the e-skin of a realistic prosthetic hand.

  13. A Novel Dual Separate Paths (DSP) Algorithm Providing Fault-Tolerant Communication for Wireless Sensor Networks.

    Science.gov (United States)

    Tien, Nguyen Xuan; Kim, Semog; Rhee, Jong Myung; Park, Sang Yoon

    2017-07-25

    Fault tolerance has long been a major concern for sensor communications in fault-tolerant cyber physical systems (CPSs). Network failure problems often occur in wireless sensor networks (WSNs) due to various factors such as the insufficient power of sensor nodes, the dislocation of sensor nodes, the unstable state of wireless links, and unpredictable environmental interference. Fault tolerance is thus one of the key requirements for data communications in WSN applications. This paper proposes a novel path redundancy-based algorithm, called dual separate paths (DSP), that provides fault-tolerant communication with the improvement of the network traffic performance for WSN applications, such as fault-tolerant CPSs. The proposed DSP algorithm establishes two separate paths between a source and a destination in a network based on the network topology information. These paths are node-disjoint paths and have optimal path distances. Unicast frames are delivered from the source to the destination in the network through the dual paths, providing fault-tolerant communication and reducing redundant unicast traffic for the network. The DSP algorithm can be applied to wired and wireless networks, such as WSNs, to provide seamless fault-tolerant communication for mission-critical and life-critical applications such as fault-tolerant CPSs. The analyzed and simulated results show that the DSP-based approach not only provides fault-tolerant communication, but also improves network traffic performance. For the case study in this paper, when the DSP algorithm was applied to high-availability seamless redundancy (HSR) networks, the proposed DSP-based approach reduced the network traffic by 80% to 88% compared with the standard HSR protocol, thus improving network traffic performance.

  14. Recession-Tolerant Sensors for Thermal Protection Systems, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II project will develop a suite of diagnostic sensors using Direct Write technology to measure temperature, surface recession depth, and heat flux of an...

  15. Clustering and fault tolerance for target tracking using wireless sensor networks

    International Nuclear Information System (INIS)

    Bhatti, S.; Khanzada, S.; Memon, S.

    2012-01-01

    Over the last few years, the deployment of WSNs (Wireless Sensor Networks) has been fostered in diverse applications. WSN has great potential for a variety of domains ranging from scientific experiments to commercial applications. Due to the deployment of WSNs in dynamic and unpredictable environments. They have potential to cope with variety of faults. This paper proposes an energy-aware fault-tolerant clustering protocol for target tracking applications termed as the FITf (Fault Tolerant Target Tracking) protocol The identification of RNs (Redundant Nodes) makes SN (Sensor Node) fault tolerance plausible and the clustering endorsed recovery of sensors supervised by a faulty CH (Cluster Head). The FfTT protocol intends two steps of reducing energy consumption: first, by identifying RNs in the network; secondly, by restricting the numbers of SNs sending data to the CH. Simulations validate the scalability and low power consumption of the FITf protocol in comparison with LEACH protocol. (author)

  16. Guaranteed Cost Fault-Tolerant Control for Networked Control Systems with Sensor Faults

    Directory of Open Access Journals (Sweden)

    Qixin Zhu

    2015-01-01

    Full Text Available For the large scale and complicated structure of networked control systems, time-varying sensor faults could inevitably occur when the system works in a poor environment. Guaranteed cost fault-tolerant controller for the new networked control systems with time-varying sensor faults is designed in this paper. Based on time delay of the network transmission environment, the networked control systems with sensor faults are modeled as a discrete-time system with uncertain parameters. And the model of networked control systems is related to the boundary values of the sensor faults. Moreover, using Lyapunov stability theory and linear matrix inequalities (LMI approach, the guaranteed cost fault-tolerant controller is verified to render such networked control systems asymptotically stable. Finally, simulations are included to demonstrate the theoretical results.

  17. Fault-tolerant topology in the wireless sensor networks for energy depletion and random failure

    International Nuclear Information System (INIS)

    Liu Bin; Dong Ming-Ru; Yin Rong-Rong; Yin Wen-Xiao

    2014-01-01

    Nodes in the wireless sensor networks (WSNs) are prone to failure due to energy depletion and poor environment, which could have a negative impact on the normal operation of the network. In order to solve this problem, in this paper, we build a fault-tolerant topology which can effectively tolerate energy depletion and random failure. Firstly, a comprehensive failure model about energy depletion and random failure is established. Then an improved evolution model is presented to generate a fault-tolerant topology, and the degree distribution of the topology can be adjusted. Finally, the relation between the degree distribution and the topological fault tolerance is analyzed, and the optimal value of evolution model parameter is obtained. Then the target fault-tolerant topology which can effectively tolerate energy depletion and random failure is obtained. The performances of the new fault tolerant topology are verified by simulation experiments. The results show that the new fault tolerant topology effectively prolongs the network lifetime and has strong fault tolerance. (general)

  18. A top-contacted extraordinary magnetoresistance sensor fabricated with an unpatterned semiconductor epilayer

    KAUST Repository

    Sun, Jian; Kosel, Jü rgen

    2013-01-01

    An extraordinary magnetoresistance device is developed from an unpatterned semiconductor epilayer onto which the metal contacts are fabricated. Compared with conventionally fabricated devices, for which semiconductor patterning and precise alignment

  19. An Adaptive Fault-Tolerant Communication Scheme for Body Sensor Networks

    Directory of Open Access Journals (Sweden)

    Zichuan Xu

    2010-10-01

    Full Text Available A high degree of reliability for critical data transmission is required in body sensor networks (BSNs. However, BSNs are usually vulnerable to channel impairments due to body fading effect and RF interference, which may potentially cause data transmission to be unreliable. In this paper, an adaptive and flexible fault-tolerant communication scheme for BSNs, namely AFTCS, is proposed. AFTCS adopts a channel bandwidth reservation strategy to provide reliable data transmission when channel impairments occur. In order to fulfill the reliability requirements of critical sensors, fault-tolerant priority and queue are employed to adaptively adjust the channel bandwidth allocation. Simulation results show that AFTCS can alleviate the effect of channel impairments, while yielding lower packet loss rate and latency for critical sensors at runtime.

  20. Intelligent Combustion. A gas boiler with a new control and safety device using the signals of a semiconductor-sensor

    International Nuclear Information System (INIS)

    Rusche, S.; Kostrzewa, G.

    1999-01-01

    The present controls of small gas boilers use an actual differential pressure of the flowing air to regulate the gas valve. It is also possible to combine the change of the gas flow rate and the air volume mechanically. In both of these methods, it is neglected that the air volume required for complete combustion is strongly affected by changing gas quality. The article discusses the use of a BaSnO3 semiconductor control sensor, which is heated by the flame and changes electrical resistance with temperature, O2 and CO content in the burning chamber. It also describes a new burner concept using the sensor

  1. Active Fault-Tolerant Control for Wind Turbine with Simultaneous Actuator and Sensor Faults

    Directory of Open Access Journals (Sweden)

    Lei Wang

    2017-01-01

    Full Text Available The purpose of this paper is to show a novel fault-tolerant tracking control (FTC strategy with robust fault estimation and compensating for simultaneous actuator sensor faults. Based on the framework of fault-tolerant control, developing an FTC design method for wind turbines is a challenge and, thus, they can tolerate simultaneous pitch actuator and pitch sensor faults having bounded first time derivatives. The paper’s key contribution is proposing a descriptor sliding mode method, in which for establishing a novel augmented descriptor system, with which we can estimate the state of system and reconstruct fault by designing descriptor sliding mode observer, the paper introduces an auxiliary descriptor state vector composed by a system state vector, actuator fault vector, and sensor fault vector. By the optimized method of LMI, the conditions for stability that estimated error dynamics are set up to promote the determination of the parameters designed. With this estimation, and designing a fault-tolerant controller, the system’s stability can be maintained. The effectiveness of the design strategy is verified by implementing the controller in the National Renewable Energy Laboratory’s 5-MW nonlinear, high-fidelity wind turbine model (FAST and simulating it in MATLAB/Simulink.

  2. Delay-tolerant mobile network protocol for rice field monitoring using wireless sensor networks

    Science.gov (United States)

    Guitton, Alexandre; Andres, Frédéric; Cardoso, Jarbas Lopes; Kawtrakul, Asanee; Barbin, Silvio E.

    2015-10-01

    The monitoring of rice fields can improve productivity by helping farmers throughout the rice cultivation cycle, on various issues: when to harvest, when to treat the crops against disease, when to increase the water level, how to share observations and decisions made in a collaborative way, etc. In this paper, we propose an architecture to monitor a rice field by a wireless sensor network. Our architecture is based on static sensor nodes forming a disconnected network, and mobile nodes communicating with the sensor nodes in a delay-tolerant manner. The data collected by the static sensor nodes are transmitted to mobile nodes, which in turn transmit them to a gateway, connected to a database, for further analysis. We focus on the related architecture, as well as on the energy-efficient protocols intended to perform the data collection.

  3. Radiation tolerant fiber optic humidity sensors for High Energy Physics applications

    CERN Document Server

    Berruti, Gaia Maria; Cusano, Andrea

    This work is devoted to the development of fiber optic humidity sensors to be applied in high-energy physics applications and in particular in experiments currently running at CERN. The high radiation level resulting from the operation of the accelerator at full luminosity can cause serious performance deterioration of the silicon sensors which are responsible for the particle tracking. To increase their lifetime, the sensors must be kept cold at temperatures below 0 C. At such low temperatures, any condensation risk has to be prevented and a precise thermal and hygrometric control of the air filling and surrounding the tracker detector cold volumes is mandatory. The technologies proposed at CERN for relative humidity monitoring are mainly based on capacitive sensing elements which are not designed with radiation resistance characteristic. In this scenario, fiber optic sensors seem to be perfectly suitable. Indeed, the fiber itself, if properly selected, can tolerate a very high level of radiation, optical fi...

  4. Fault-Tolerant Robot Programming through Simulation with Realistic Sensor Models

    Directory of Open Access Journals (Sweden)

    Axel Waggershauser

    2008-11-01

    Full Text Available We introduce a simulation system for mobile robots that allows a realistic interaction of multiple robots in a common environment. The simulated robots are closely modeled after robots from the EyeBot family and have an identical application programmer interface. The simulation supports driving commands at two levels of abstraction as well as numerous sensors such as shaft encoders, infrared distance sensors, and compass. Simulation of on-board digital cameras via synthetic images allows the use of image processing routines for robot control within the simulation. Specific error models for actuators, distance sensors, camera sensor, and wireless communication have been implemented. Progressively increasing error levels for an application program allows for testing and improving its robustness and fault-tolerance.

  5. Practical Use of Metal Oxide Semiconductor Gas Sensors for Measuring Nitrogen Dioxide and Ozone in Urban Environments.

    Science.gov (United States)

    Peterson, Philip J D; Aujla, Amrita; Grant, Kirsty H; Brundle, Alex G; Thompson, Martin R; Vande Hey, Josh; Leigh, Roland J

    2017-07-19

    The potential of inexpensive Metal Oxide Semiconductor (MOS) gas sensors to be used for urban air quality monitoring has been the topic of increasing interest in the last decade. This paper discusses some of the lessons of three years of experience working with such sensors on a novel instrument platform (Small Open General purpose Sensor (SOGS)) in the measurement of atmospheric nitrogen dioxide and ozone concentrations. Analytic methods for increasing long-term accuracy of measurements are discussed, which permit nitrogen dioxide measurements with 95% confidence intervals of 20.0 μ g m - 3 and ozone precision of 26.8 μ g m - 3 , for measurements over a period one month away from calibration, averaged over 18 months of such calibrations. Beyond four months from calibration, sensor drift becomes significant, and accuracy is significantly reduced. Successful calibration schemes are discussed with the use of controlled artificial atmospheres complementing deployment on a reference weather station exposed to the elements. Manufacturing variation in the attributes of individual sensors are examined, an experiment possible due to the instrument being equipped with pairs of sensors of the same kind. Good repeatability (better than 0.7 correlation) between individual sensor elements is shown. The results from sensors that used fans to push air past an internal sensor element are compared with mounting the sensors on the outside of the enclosure, the latter design increasing effective integration time to more than a day. Finally, possible paths forward are suggested for improving the reliability of this promising sensor technology for measuring pollution in an urban environment.

  6. Vibration-tolerant narrow-linewidth semiconductor disk laser using novel frequency-stabilisation schemes

    Science.gov (United States)

    Hunter, Craig R.; Jones, Brynmor E.; Schlosser, Peter; Sørensen, Simon Toft; Strain, Michael J.; McKnight, Loyd J.

    2018-02-01

    This paper will present developments in narrow-linewidth semiconductor-disk-laser systems using novel frequencystabilisation schemes for reduced sensitivity to mechanical vibrations, a critical requirement for mobile applications. Narrow-linewidth single-frequency lasers are required for a range of applications including metrology and highresolution spectroscopy. Stabilisation of the laser was achieved using a monolithic fibre-optic ring resonator with free spectral range of 181 MHz and finesse of 52 to act as passive reference cavity for the laser. Such a cavity can operate over a broad wavelength range and is immune to a wide band of vibrational frequency noise due to its monolithic implementation. The frequency noise of the locked system has been measured and compared to typical Fabry-Perotlocked lasers using vibration equipment to simulate harsh environments, and analysed here. Locked linewidths of portable, narrow-linewidth laser system for harsh environments that can be flexibly designed for a range of applications.

  7. A Customized Metal Oxide Semiconductor-Based Gas Sensor Array for Onion Quality Evaluation: System Development and Characterization

    Directory of Open Access Journals (Sweden)

    Tharun Konduru

    2015-01-01

    Full Text Available A gas sensor array, consisting of seven Metal Oxide Semiconductor (MOS sensors that are sensitive to a wide range of organic volatile compounds was developed to detect rotten onions during storage. These MOS sensors were enclosed in a specially designed Teflon chamber equipped with a gas delivery system to pump volatiles from the onion samples into the chamber. The electronic circuit mainly comprised a microcontroller, non-volatile memory chip, and trickle-charge real time clock chip, serial communication chip, and parallel LCD panel. User preferences are communicated with the on-board microcontroller through a graphical user interface developed using LabVIEW. The developed gas sensor array was characterized and the discrimination potential was tested by exposing it to three different concentrations of acetone (ketone, acetonitrile (nitrile, ethyl acetate (ester, and ethanol (alcohol. The gas sensor array could differentiate the four chemicals of same concentrations and different concentrations within the chemical with significant difference. Experiment results also showed that the system was able to discriminate two concentrations (196 and 1964 ppm of methlypropyl sulfide and two concentrations (145 and 1452 ppm of 2-nonanone, two key volatile compounds emitted by rotten onions. As a proof of concept, the gas sensor array was able to achieve 89% correct classification of sour skin infected onions. The customized low-cost gas sensor array could be a useful tool to detect onion postharvest diseases in storage.

  8. ARTIST: advanced radiation-tolerant information and sensor system for teleoperation

    International Nuclear Information System (INIS)

    Schmidt, D.; Pathe, V.; Ostertag, M.; Dittrich, F.; Dumbreck, A.; Sirat, G.; Katzouraki, M.

    1993-01-01

    ARTIST integrates a stereoscopic camera and a rangefinder as sensor package into a high-precision pan-and-tilt head and represents the recorded data in a clear and comprehensive way for telemanipulation and control tasks as well as for remote driving. The sensors as well as the pan-and-tilt head are radiation-tolerant so they can be used in nuclear environments. The pan-and-tilt head and work station are completely configured and developed with the emphasis on multisensor integration, real-time video processing and graphical position representation. An efficient man-machine-interface appropriate software is included. (author)

  9. Tolerance Towards Sensor Faults: An Application to a Flexible Arm Manipulator

    Directory of Open Access Journals (Sweden)

    Chee Pin Tan

    2006-12-01

    Full Text Available As more engineering operations become automatic, the need for robustness towards faults increases. Hence, a fault tolerant control (FTC scheme is a valuable asset. This paper presents a robust sensor fault FTC scheme implemented on a flexible arm manipulator, which has many applications in automation. Sensor faults affect the system's performance in the closed loop when the faulty sensor readings are used to generate the control input. In this paper, the non-faulty sensors are used to reconstruct the faults on the potentially faulty sensors. The reconstruction is subtracted from the faulty sensors to form a compensated ‘virtual sensor’ and this signal (instead of the normally used faulty sensor output is then used to generate the control input. A design method is also presented in which the FTC scheme is made insensitive to any system uncertainties. Two fault conditions are tested; total failure and incipient faults. Then the scheme robustness is tested by implementing the flexible joint's FTC scheme on a flexible link, which has different parameters. Excellent results have been obtained for both cases (joint and link; the FTC scheme caused the system performance is almost identical to the fault-free scenario, whilst providing an indication that a fault is present, even for simultaneous faults.

  10. Conceptual design of a versatile radiation tolerant integrated signal conditioning circuit for resistive sensors

    Energy Technology Data Exchange (ETDEWEB)

    Leroux, P. [Katholieke Hogeschool Kempen, Kleinhoefstraat 4, B-2440 Geel (Belgium); Katholieke Universiteit Leuven, Dept. ESAT-MICAS, Kasteelpark Arenberg 10, B-3001 Heverlee (Belgium); SCK-CEN, Belgian Nuclear Research Centre, Boeretang 200, B-2400 Mol (Belgium); Sterckx, J. [Katholieke Hogeschool Kempen, Kleinhoefstraat 4, B-2440 Geel (Belgium); Van Uffelen, M.; Damiani, C. [Fusion 4 Energy, Ed. B3, c/Josep, no 2, Torres Diagonal Litoral, 08019 Barcelona (Spain)

    2011-07-01

    This paper presents the design of a radiation tolerant configurable discrete time CMOS signal conditioning circuit for use with resistive sensors like strain gauge pressure sensors. The circuit is intended to be used for remote handling in harsh environments in the International Thermonuclear Experimental fusion Reactor (ITER). The design features a 5 V differential preamplifier using a Correlated Double Sampling (CDS) architecture at a sample rate of 20 kHz and a 24 V discrete time post amplifier. The gain is digitally controllable between 27 and 400 in the preamplifier and between 1 and 8 in the post amplifier. The nominal input referred noise voltage is only 8.5 {mu}V while consuming only 1 mW. The circuit has a simulated radiation tolerance of more than 1 MGy. (authors)

  11. Delay-Tolerant, Low-Power Protocols for Large Security-Critical Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Claudio S. Malavenda

    2012-01-01

    Full Text Available This paper reports the analysis, implementation, and experimental testing of a delay-tolerant and energy-aware protocol for a wireless sensor node, oriented to security applications. The solution proposed takes advantages from different domains considering as a guideline the low power consumption and facing the problems of seamless and lossy connectivity offered by the wireless medium along with very limited resources offered by a wireless network node. The paper is organized as follows: first we give an overview on delay-tolerant wireless sensor networking (DTN; then we perform a simulation-based comparative analysis of state-of-the-art DTN approaches and illustrate the improvement offered by the proposed protocol; finally we present experimental data gathered from the implementation of the proposed protocol on a proprietary hardware node.

  12. Deep-Sea DuraFET: A Pressure Tolerant pH Sensor Designed for Global Sensor Networks.

    Science.gov (United States)

    Johnson, Kenneth S; Jannasch, Hans W; Coletti, Luke J; Elrod, Virginia A; Martz, Todd R; Takeshita, Yuichiro; Carlson, Robert J; Connery, James G

    2016-03-15

    Increasing atmospheric carbon dioxide is driving a long-term decrease in ocean pH which is superimposed on daily to seasonal variability. These changes impact ecosystem processes, and they serve as a record of ecosystem metabolism. However, the temporal variability in pH is observed at only a few locations in the ocean because a ship is required to support pH observations of sufficient precision and accuracy. This paper describes a pressure tolerant Ion Sensitive Field Effect Transistor pH sensor that is based on the Honeywell Durafet ISFET die. When combined with a AgCl pseudoreference sensor that is immersed directly in seawater, the system is capable of operating for years at a time on platforms that cycle from depths of several km to the surface. The paper also describes the calibration scheme developed to allow calibrated pH measurements to be derived from the activity of HCl reported by the sensor system over the range of ocean pressure and temperature. Deployments on vertical profiling platforms enable self-calibration in deep waters where pH values are stable. Measurements with the sensor indicate that it is capable of reporting pH with an accuracy of 0.01 or better on the total proton scale and a precision over multiyear periods of 0.005. This system enables a global ocean observing system for ocean pH.

  13. Fault-tolerant cooperative output regulation for multi-vehicle systems with sensor faults

    Science.gov (United States)

    Qin, Liguo; He, Xiao; Zhou, D. H.

    2017-10-01

    This paper presents a unified framework of fault diagnosis and fault-tolerant cooperative output regulation (FTCOR) for a linear discrete-time multi-vehicle system with sensor faults. The FTCOR control law is designed through three steps. A cooperative output regulation (COR) controller is designed based on the internal mode principle when there are no sensor faults. A sufficient condition on the existence of the COR controller is given based on the discrete-time algebraic Riccati equation (DARE). Then, a decentralised fault diagnosis scheme is designed to cope with sensor faults occurring in followers. A residual generator is developed to detect sensor faults of each follower, and a bank of fault-matching estimators are proposed to isolate and estimate sensor faults of each follower. Unlike the current distributed fault diagnosis for multi-vehicle systems, the presented decentralised fault diagnosis scheme in each vehicle reduces the communication and computation load by only using the information of the vehicle. By combing the sensor fault estimation and the COR control law, an FTCOR controller is proposed. Finally, the simulation results demonstrate the effectiveness of the FTCOR controller.

  14. Effect of Water Vapor and Surface Morphology on the Low Temperature Response of Metal Oxide Semiconductor Gas Sensors

    Directory of Open Access Journals (Sweden)

    Konrad Maier

    2015-09-01

    Full Text Available In this work the low temperature response of metal oxide semiconductor gas sensors is analyzed. Important characteristics of this low-temperature response are a pronounced selectivity to acid- and base-forming gases and a large disparity of response and recovery time constants which often leads to an integrator-type of gas response. We show that this kind of sensor performance is related to the trend of semiconductor gas sensors to adsorb water vapor in multi-layer form and that this ability is sensitively influenced by the surface morphology. In particular we show that surface roughness in the nanometer range enhances desorption of water from multi-layer adsorbates, enabling them to respond more swiftly to changes in the ambient humidity. Further experiments reveal that reactive gases, such as NO2 and NH3, which are easily absorbed in the water adsorbate layers, are more easily exchanged across the liquid/air interface when the humidity in the ambient air is high.

  15. Development and characterization of a semi-conductor laser sensor for real time measurement and identification of atmospheric pollutants

    International Nuclear Information System (INIS)

    Boulos, F.; Zaatar, Y.; Atanas, J.P.; Bechara, J.

    2004-01-01

    Full text.Tunable diode laser absorption spectroscopy (TDLAS) in the near infrared (NIR) using semiconductor lasers of compounds between elements of group III (Ga, Al and In) and group V (P, As and Sb) is being increasingly used in various environmental and industrial process control applications. This technique exploits the unique properties of these laser materials i.e., high coherence, high monochromaticity, low divergence and high brightness to permit rapid sensitive detection with high selectivity and spectral resolution. A computer-interfaced near infrared semiconductor laser sensor has been developed in our laboratory for spectroscopic applications in air pollution monitoring. The sensor can be operated in two configurations: open path free beam coupled to a multiple pass White cell and fiber optic guided beam coupled to an evanescent wave sensor. This paper will present an overview of the system's modulation, sensing and data acquisition methods and some recent measurement results, together with a description of ongoing research and development for the improvement of the system's performance and sensitivity

  16. A top-contacted extraordinary magnetoresistance sensor fabricated with an unpatterned semiconductor epilayer

    KAUST Repository

    Sun, Jian

    2013-04-01

    An extraordinary magnetoresistance device is developed from an unpatterned semiconductor epilayer onto which the metal contacts are fabricated. Compared with conventionally fabricated devices, for which semiconductor patterning and precise alignment are required, this design is not only easier from a technological point of view, but it also has the potential to reduce damage introduced to the semiconductor during fabrication. The device shows a similar magnetoresistance ratio as a conventional one but it has a lower sensitivity. Because of the reduced resistance, and hence less noise, high magnetic field resolution is maintained. © 1980-2012 IEEE.

  17. Pitch dependence of the tolerance of CMOS monolithic active pixel sensors to non-ionizing radiation

    International Nuclear Information System (INIS)

    Doering, D.; Deveaux, M.; Domachowski, M.; Fröhlich, I.; Koziel, M.; Müntz, C.; Scharrer, P.; Stroth, J.

    2013-01-01

    CMOS monolithic active pixel sensors (MAPS) have demonstrated excellent performance as tracking detectors for charged particles. They provide an outstanding spatial resolution (a few μm), a detection efficiency of ≳99.9%, very low material budget (0.05%X 0 ) and good radiation tolerance (≳1Mrad, ≳10 13 n eq /cm 2 ) (Deveaux et al. [1]). This makes them an interesting technology for various applications in heavy ion and particle physics. Their tolerance to bulk damage was recently improved by using high-resistivity (∼1kΩcm) epitaxial layers as sensitive volume (Deveaux et al. [1], Dorokhov et al. [2]). The radiation tolerance of conventional MAPS is known to depend on the pixel pitch. This is as a higher pitch extends the distance, which signal electrons have to travel by thermal diffusion before being collected. Increased diffusion paths turn into a higher probability of loosing signal charge due to recombination. Provided that a similar effect exists in MAPS with high-resistivity epitaxial layer, it could be used to extend their radiation tolerance further. We addressed this question with MIMOSA-18AHR prototypes, which were provided by the IPHC Strasbourg and irradiated with reactor neutrons. We report about the results of this study and provide evidences that MAPS with 10μm pixel pitch tolerate doses of ≳3×10 14 n eq /cm 2

  18. Chip-scale fluorescence microscope based on a silo-filter complementary metal-oxide semiconductor image sensor.

    Science.gov (United States)

    Ah Lee, Seung; Ou, Xiaoze; Lee, J Eugene; Yang, Changhuei

    2013-06-01

    We demonstrate a silo-filter (SF) complementary metal-oxide semiconductor (CMOS) image sensor for a chip-scale fluorescence microscope. The extruded pixel design with metal walls between neighboring pixels guides fluorescence emission through the thick absorptive filter to the photodiode of a pixel. Our prototype device achieves 13 μm resolution over a wide field of view (4.8 mm × 4.4 mm). We demonstrate bright-field and fluorescence longitudinal imaging of living cells in a compact, low-cost configuration.

  19. Influence of semiconductor/metal interface geometry in an EMR sensor

    KAUST Repository

    Sun, Jian; Kosel, Jü rgen

    2013-01-01

    The extraordinary magnetoresistance (EMR) is well known to be strongly dependent on geometric parameters. While the influence of the aspect ratios of the metal and semiconductor areas has been thoroughly investigated, the geometry

  20. Temperature Modulation with Specified Detection Point on Metal Oxide Semiconductor Gas Sensors for E-Nose Application

    Directory of Open Access Journals (Sweden)

    Arief SUDARMAJI

    2015-03-01

    Full Text Available Temperature modulation technique, some called dynamic measurement mode, on Metal-Oxide Semiconductor (MOS/MOX gas sensor has been widely observed and employed in many fields. We present its development, a Specified Detection Point (SDP on modulated sensing element of MOS sensor is applied which associated to its temperature modulation, temperature modulation-SDP so-named. We configured the rectangular modulation signal for MOS gas sensors (TGSs and FISs using PSOC CY8C28445-24PVXI (Programmable System on Chip which also functioned as acquisition unit and interface to a computer. Initial responses and selectivity evaluations were performed using statistical tool and Principal Component Analysis (PCA to differ sample gases (Toluene, Ethanol and Ammonia on dynamic chamber measurement under various frequencies (0.25 Hz, 1 Hz, 4 Hz and duty-cycles (25 %, 50 %, 75 %. We found that at lower frequency the response waveform of the sensors becomes more sloping and distinct, and selected modulations successfully increased the selectivity either on singular or array sensors rather than static temperature measurement.

  1. Sensor fault-tolerant control for gear-shifting engaging process of automated manual transmission

    Science.gov (United States)

    Li, Liang; He, Kai; Wang, Xiangyu; Liu, Yahui

    2018-01-01

    Angular displacement sensor on the actuator of automated manual transmission (AMT) is sensitive to fault, and the sensor fault will disturb its normal control, which affects the entire gear-shifting process of AMT and results in awful riding comfort. In order to solve this problem, this paper proposes a method of fault-tolerant control for AMT gear-shifting engaging process. By using the measured current of actuator motor and angular displacement of actuator, the gear-shifting engaging load torque table is built and updated before the occurrence of the sensor fault. Meanwhile, residual between estimated and measured angular displacements is used to detect the sensor fault. Once the residual exceeds a determined fault threshold, the sensor fault is detected. Then, switch control is triggered, and the current observer and load torque table estimates an actual gear-shifting position to replace the measured one to continue controlling the gear-shifting process. Numerical and experiment tests are carried out to evaluate the reliability and feasibility of proposed methods, and the results show that the performance of estimation and control is satisfactory.

  2. Tolerance

    DEFF Research Database (Denmark)

    Tønder, Lars

    is linked to a different set of circumstances than the ones suggested by existing models in contemporary democratic theory. Reorienting the discussion of tolerance, the book raises the question of how to disclose new possibilities within our given context of affect and perception. Once we move away from......Tolerance: A Sensorial Orientation to Politics is an experiment in re-orientation. The book is based on the wager that tolerance exceeds the more prevalent images of self-restraint and repressive benevolence because neither precludes the possibility of a more “active tolerance” motivated...... by the desire to experiment and to become otherwise. The objective is to discuss what gets lost, conceptually as well as politically, when we neglect the subsistence of active tolerance within other practices of tolerance, and to develop a theory of active tolerance in which tolerance's mobilizing character...

  3. BTP: a Block Transfer Protocol for Delay Tolerant Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Hansen, Morten Tranberg; Biagioni, Edoardo S.

    2010-01-01

    Wireless sensor networks that are energy-constrained must transmit and receive data as efficiently as possible.  If the transmission is delay tolerant, transferring blocks of accumulated data can be more efficient than transferring each sensed measurement as soon as it is available.  This paper...... proposes a Block Transfer Protocol (BTP) designed for efficient and reliable transmission in wireless sensor networks.  BTP reduces the time it takes to reliably transfer a block of packets compared to conventional link layer protocols, by piggybacking in data packets information about the transfer......, minimizing the number of acknowledgements needed for reliable transmission, and reducing the need for timeouts, which can substantially slow down communication when transmission is unreliable.  In addition, BTP improves reliability by handling false positive acknowledgements and by letting the receivers...

  4. Sensor-driven, fault-tolerant control of a maintenance robot

    International Nuclear Information System (INIS)

    Moy, M.M.; Davidson, W.M.

    1987-01-01

    A robot system has been designed to do routine maintenance tasks on the Sandia Pulsed Reactor (SPR). The use of this Remote Maintenance Robot (RMR) is expected to significantly reduce the occupational radiation exposure of the reactor operators. Reactor safety was a key issue in the design of the robot maintenance system. Using sensors to detect error conditions and intelligent control to recover from the errors, the RMR is capable of responding to error conditions without creating a hazard. This paper describes the design and implementation of a sensor-driven, fault-tolerant control for the RMR. Recovery from errors is not automatic; it does rely on operator assistance. However, a key feature of the error recovery procedure is that the operator is allowed to reenter the programmed operation after the error has been corrected. The recovery procedure guarantees that the moving components of the system will not collide with the reactor during recovery

  5. Integrated semiconductor optical sensors for chronic, minimally-invasive imaging of brain function.

    Science.gov (United States)

    Lee, Thomas T; Levi, Ofer; Cang, Jianhua; Kaneko, Megumi; Stryker, Michael P; Smith, Stephen J; Shenoy, Krishna V; Harris, James S

    2006-01-01

    Intrinsic optical signal (IOS) imaging is a widely accepted technique for imaging brain activity. We propose an integrated device consisting of interleaved arrays of gallium arsenide (GaAs) based semiconductor light sources and detectors operating at telecommunications wavelengths in the near-infrared. Such a device will allow for long-term, minimally invasive monitoring of neural activity in freely behaving subjects, and will enable the use of structured illumination patterns to improve system performance. In this work we describe the proposed system and show that near-infrared IOS imaging at wavelengths compatible with semiconductor devices can produce physiologically significant images in mice, even through skull.

  6. Tolerance

    DEFF Research Database (Denmark)

    Tønder, Lars

    Tolerance: A Sensorial Orientation to Politics is an experiment in re-orientation. The book is based on the wager that tolerance exceeds the more prevalent images of self-restraint and repressive benevolence because neither precludes the possibility of a more “active tolerance” motivated by the d...... these alternatives by returning to the notion of tolerance as the endurance of pain, linking this notion to exemplars and theories relevant to the politics of multiculturalism, religious freedom, and free speech....

  7. 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.

  8. An Autonomous Self-Aware and Adaptive Fault Tolerant Routing Technique for Wireless Sensor Networks.

    Science.gov (United States)

    Abba, Sani; Lee, Jeong-A

    2015-08-18

    We propose an autonomous self-aware and adaptive fault-tolerant routing technique (ASAART) for wireless sensor networks. We address the limitations of self-healing routing (SHR) and self-selective routing (SSR) techniques for routing sensor data. We also examine the integration of autonomic self-aware and adaptive fault detection and resiliency techniques for route formation and route repair to provide resilience to errors and failures. We achieved this by using a combined continuous and slotted prioritized transmission back-off delay to obtain local and global network state information, as well as multiple random functions for attaining faster routing convergence and reliable route repair despite transient and permanent node failure rates and efficient adaptation to instantaneous network topology changes. The results of simulations based on a comparison of the ASAART with the SHR and SSR protocols for five different simulated scenarios in the presence of transient and permanent node failure rates exhibit a greater resiliency to errors and failure and better routing performance in terms of the number of successfully delivered network packets, end-to-end delay, delivered MAC layer packets, packet error rate, as well as efficient energy conservation in a highly congested, faulty, and scalable sensor network.

  9. An Autonomous Self-Aware and Adaptive Fault Tolerant Routing Technique for Wireless Sensor Networks

    Science.gov (United States)

    Abba, Sani; Lee, Jeong-A

    2015-01-01

    We propose an autonomous self-aware and adaptive fault-tolerant routing technique (ASAART) for wireless sensor networks. We address the limitations of self-healing routing (SHR) and self-selective routing (SSR) techniques for routing sensor data. We also examine the integration of autonomic self-aware and adaptive fault detection and resiliency techniques for route formation and route repair to provide resilience to errors and failures. We achieved this by using a combined continuous and slotted prioritized transmission back-off delay to obtain local and global network state information, as well as multiple random functions for attaining faster routing convergence and reliable route repair despite transient and permanent node failure rates and efficient adaptation to instantaneous network topology changes. The results of simulations based on a comparison of the ASAART with the SHR and SSR protocols for five different simulated scenarios in the presence of transient and permanent node failure rates exhibit a greater resiliency to errors and failure and better routing performance in terms of the number of successfully delivered network packets, end-to-end delay, delivered MAC layer packets, packet error rate, as well as efficient energy conservation in a highly congested, faulty, and scalable sensor network. PMID:26295236

  10. Evaluation of testing strategies for the radiation tolerant ATLAS n **+-in-n pixel sensor

    CERN Document Server

    Klaiber Lodewigs, Jonas M

    2003-01-01

    The development of particle tracker systems for high fluence environments in new high-energy physics experiments raises new challenges for the development, manufacturing and reliable testing of radiation tolerant components. The ATLAS pixel detector for use at the LHC, CERN, is designed to cover an active sensor area of 1.8 m**2 with 1.1 multiplied by 10 **8 read-out channels usable for a particle fluence up to 10 **1**5 cm**-**2 (1 MeV neutron equivalent) and an ionization dose up to 500 kGy of mainly charged hadron radiation. To cope with such a harsh environment the ATLAS Pixel Collaboration has developed a radiation hard n **+-in-n silicon pixel cell design with a standard cell size of 50 multiplied by 400 mum**2. Using this design on an oxygenated silicon substrate, sensor production has started in 2001. This contribution describes results gained during the development of testing procedures of the ATLAS pixel sensor and evaluates quality assurance procedures regarding their relevance for detector operati...

  11. Virtual Sensor of Surface Electromyography in a New Extensive Fault-Tolerant Classification System.

    Science.gov (United States)

    de Moura, Karina de O A; Balbinot, Alexandre

    2018-05-01

    A few prosthetic control systems in the scientific literature obtain pattern recognition algorithms adapted to changes that occur in the myoelectric signal over time and, frequently, such systems are not natural and intuitive. These are some of the several challenges for myoelectric prostheses for everyday use. The concept of the virtual sensor, which has as its fundamental objective to estimate unavailable measures based on other available measures, is being used in other fields of research. The virtual sensor technique applied to surface electromyography can help to minimize these problems, typically related to the degradation of the myoelectric signal that usually leads to a decrease in the classification accuracy of the movements characterized by computational intelligent systems. This paper presents a virtual sensor in a new extensive fault-tolerant classification system to maintain the classification accuracy after the occurrence of the following contaminants: ECG interference, electrode displacement, movement artifacts, power line interference, and saturation. The Time-Varying Autoregressive Moving Average (TVARMA) and Time-Varying Kalman filter (TVK) models are compared to define the most robust model for the virtual sensor. Results of movement classification were presented comparing the usual classification techniques with the method of the degraded signal replacement and classifier retraining. The experimental results were evaluated for these five noise types in 16 surface electromyography (sEMG) channel degradation case studies. The proposed system without using classifier retraining techniques recovered of mean classification accuracy was of 4% to 38% for electrode displacement, movement artifacts, and saturation noise. The best mean classification considering all signal contaminants and channel combinations evaluated was the classification using the retraining method, replacing the degraded channel by the virtual sensor TVARMA model. This method

  12. The theory of surface-enhanced Raman scattering on semiconductor nanoparticles; toward the optimization of SERS sensors.

    Science.gov (United States)

    Lombardi, John R

    2017-12-04

    We present an expression for the lowest order nonzero contribution to the surface-enhanced Raman spectrum obtained from a system of a molecule adsorbed on a semiconductor nanoparticle. Herzberg-Teller vibronic coupling of the zero-order Born-Oppenheimer states results in an expression which may be regarded as an extension of the Albrecht A-, B-, and C-terms to SERS substrates. We show that the SERS enhancement is caused by combinations of several types of resonances in the combined system, namely, surface, exciton, charge-transfer, and molecular resonances. These resonances are coupled by terms in the numerator, which provide selection rules that enable various tests of the theory and predict the relative intensities of the Raman lines. Furthermore, by considering interactions of the various contributions to the SERS enhancement, we are able to develop ways to optimize the enhancement factor by tailoring the semiconductor nanostructure, thereby adjusting the locations of the various contributing resonances. This provides a procedure by which molecular sensors can be constructed and optimized. We provide several experimental examples on substrates such as monolayer MoS 2 and GaN nanorods.

  13. Ratiometric, filter-free optical sensor based on a complementary metal oxide semiconductor buried double junction photodiode.

    Science.gov (United States)

    Yung, Ka Yi; Zhan, Zhiyong; Titus, Albert H; Baker, Gary A; Bright, Frank V

    2015-07-16

    We report a complementary metal oxide semiconductor integrated circuit (CMOS IC) with a buried double junction (BDJ) photodiode that (i) provides a real-time output signal that is related to the intensity ratio at two emission wavelengths and (ii) simultaneously eliminates the need for an optical filter to block Rayleigh scatter. We demonstrate the BDJ platform performance for gaseous NH3 and aqueous pH detection. We also compare the BDJ performance to parallel results obtained by using a slew scanned fluorimeter (SSF). The BDJ results are functionally equivalent to the SSF results without the need for any wavelength filtering or monochromators and the BDJ platform is not prone to errors associated with source intensity fluctuations or sensor signal drift. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Water quality assessment by an integrated multi-sensor based on semiconductor RuO2 nanostructures

    International Nuclear Information System (INIS)

    Zhuiykov, Serge; O'Brien, David; Best, Michael

    2009-01-01

    A multi-sensor based on a nanostructured semiconductor ruthenium oxide (RuO 2 ) sensing electrode (RuO 2 -SE) deposited on an alumina substrate and capable of being coupled with a simple turbidity sensor has been evaluated for long-term pH stability during a 12-month non-stop trial. The multi-sensor is designed to detect the main parameters of water quality: pH, dissolved oxygen (DO), temperature, conductivity and turbidity over a temperature range of 9–30 °C. The morphology of the film SE used in the sensor structure was investigated by scanning electron microscopy and energy dispersive x-ray-analysis at the beginning of the trial and after 12 months of service. It was found that both morphology and surface compositions of nanostructured RuO 2 -SEs did not change significantly. They keep their high sensitivity to adsorption of superoxide ions (O 2 − ) despite heavy depositions of bio-fouling. The sensors with a RuO 2 -SE have demonstrated a stable Nernstian response to pH from 2.0 to 13.0 and were also capable of measuring DO in the range of 0.6–8.0 ppm. The measurement results show very good linearity, and excellent reproducibility was obtained during the trial. The Nernstian slope was approximately 58 mV pH −1 at a temperature of 23 °C. Although RuO 2 -SEs have been shown to exhibit very good response time for pH changes, within a few seconds at a temperature of 23 °C, as the water temperature cooled down, the sensor response time increased significantly and was about 8–10 min or longer at a temperature of 9 °C. The influence of hydrogen ion (H + ) diffusion in nanostructured RuO 2 films on the output emf drift during pH measurements was also investigated. Additional turbidity and conductivity measurements revealed that the multi-sensor is capable of measuring both high and low ranges at different temperatures, exhibiting a high linearity of characteristics

  15. Adsorption smoke detector made of thin-film metal-oxide semiconductor sensor

    International Nuclear Information System (INIS)

    Adamian, A.Z.; Adamian, Z.N.; Aroutiounian, V.M.

    2001-01-01

    Based on results of investigations of the thin-film smoke sensors made of Bi 2 O 3 , irresponsive to a change in relative humidity of the environment, an absorption smoke detector processing circuit, where investigated sensor is used as a sensitive element, is proposed. It is shown that such smoke detector is able to function reliably under conditions of high relative humidity of the environment (up to 100%) and it considerably exceeds the known smoke detectors by the sensitivity threshold

  16. Adsorption smoke detector made of thin-film metal-oxide semiconductor sensor

    CERN Document Server

    Adamian, A Z; Aroutiounian, V M

    2001-01-01

    Based on results of investigations of the thin-film smoke sensors made of Bi sub 2 O sub 3 , irresponsive to a change in relative humidity of the environment, an absorption smoke detector processing circuit, where investigated sensor is used as a sensitive element, is proposed. It is shown that such smoke detector is able to function reliably under conditions of high relative humidity of the environment (up to 100%) and it considerably exceeds the known smoke detectors by the sensitivity threshold.

  17. Ultrasensitive mass sensor fully integrated with complementary metal-oxide-semiconductor circuitry

    DEFF Research Database (Denmark)

    Forsén, Esko Sebastian; Abadal, G.; Ghatnekar-Nilsson, S.

    2005-01-01

    Nanomechanical resonators have been monolithically integrated on preprocessed complementary metal-oxide-semiconductor (CMOS) chips. Fabricated resonator systems have been designed to have resonance frequencies up to 1.5 MHz. The systems have been characterized in ambient air and vacuum conditions...... and display ultrasensitive mass detection in air. A mass sensitivity of 4 ag/Hz has been determined in air by placing a single glycerine drop, having a measured weight of 57 fg, at the apex of a cantilever and subsequently measuring a frequency shift of 14.8 kHz. CMOS integration enables electrostatic...

  18. Fault-tolerant Control of Discrete-time LPV systems using Virtual Actuators and Sensors

    DEFF Research Database (Denmark)

    Tabatabaeipour, Mojtaba; Stoustrup, Jakob; Bak, Thomas

    2015-01-01

    This paper proposes a new fault-tolerant control (FTC) method for discrete-time linear parameter varying (LPV) systems using a reconfiguration block. The basic idea of the method is to achieve the FTC goal without re-designing the nominal controller by inserting a reconfiguration block between......, it transforms the output of the controller for the faulty system such that the stability and performance goals are preserved. Input-to-state stabilizing LPV gains of the virtual actuator and sensor are obtained by solving linear matrix inequalities (LMIs). We show that separate design of these gains guarantees....... Finally, the effectiveness of the method is demonstrated via a numerical example and stator current control of an induction motor....

  19. Energy-Efficient Fault-Tolerant Dynamic Event Region Detection in Wireless Sensor Networks

    DEFF Research Database (Denmark)

    Enemark, Hans-Jacob; Zhang, Yue; Dragoni, Nicola

    2015-01-01

    to a hybrid algorithm for dynamic event region detection, such as real-time tracking of chemical leakage regions. Considering the characteristics of the moving away dynamic events, we propose a return back condition for the hybrid algorithm from distributed neighborhood collaboration, in which a node makes......Fault-tolerant event detection is fundamental to wireless sensor network applications. Existing approaches usually adopt neighborhood collaboration for better detection accuracy, while need more energy consumption due to communication. Focusing on energy efficiency, this paper makes an improvement...... its detection decision based on decisions received from its spatial and temporal neighbors, to local non-communicative decision making. The simulation results demonstrate that the improved algorithm does not degrade the detection accuracy of the original algorithm, while it has better energy...

  20. Performance of semiconductor radiation sensors for simple and low-cost radiation detector

    International Nuclear Information System (INIS)

    Tanimura, Yoshihiko; Birumachi, Atsushi; Yoshida, Makoto; Watanabe, Tamaki

    2008-01-01

    In order to develop a simple but reliable radiation detector for the general public, photon detection performances of radiation sensors have been studied in photon calibration fields and by Monte Carlo simulations. A silicon p-i-n photodiode and a CdTe detector were selected for the low cost sensors. Their energy responses to ambient dose equivalent H * (10) were evaluated over the energy range from 60 keV to 2 MeV. The response of the CdTe decreases markedly with increasing photon energy. On the other hand, the photodiode has the advantage of almost flat response above 150 keV. The sensitivities of these sensors are 4 to 6 cpm for the natural radiation. Detection limits of the radiation level are low enough to know the extreme increase of radiation due to emergency situations of nuclear power plants, fuel treatment facilities and so on. (author)

  1. An Energy-aware Routing Scheme in Delay Tolerant Mobile Sensor Networking

    Directory of Open Access Journals (Sweden)

    Zhe Chen

    2014-08-01

    Full Text Available In Delay Tolerant Mobile Sensor Networking (DTMSN, mobile sensor nodes are usually limited to their energy capacity, one important concern in routing design of DTMSN is energy consumption. This paper presents a number of variations of the Epidemic Routing Protocol (ERP to extend the DTMSN lifetime. It introduces the analytical model for ERP, after introducing the concepts behind the Target Delivery Probability and Minimum Delivery Probability, it defines the network lifetime. In this paper, it firstly studies many variations of the Epidemic Routing Protocol to extend the lifetime of the DTMSN. Secondly, based on the Epidemic Routing Protocol, three schemes are introduced. Those schemes rely on the limiting the times of message allowed for propagation (LT scheme, directly controlling the number of the copies (LC scheme, split the copies to the residual energies of the nodes (LE scheme. Finally, with the experiment and the validation of the simulation, the LE scheme can significantly maximize the lifetime of DTMSN, because it minimizes the number of copies and that shifts the generation of the copies to the nodes with larger residual energy.

  2. A distance-aware replica adaptive data gathering protocol for Delay Tolerant Mobile Sensor Networks.

    Science.gov (United States)

    Feng, Yong; Gong, Haigang; Fan, Mingyu; Liu, Ming; Wang, Xiaomin

    2011-01-01

    In Delay Tolerant Mobile Sensor Networks (DTMSNs) that have the inherent features of intermitted connectivity and frequently changing network topology it is reasonable to utilize multi-replica schemes to improve the data gathering performance. However, most existing multi-replica approaches inject a large amount of message copies into the network to increase the probability of message delivery, which may drain each mobile node's limited battery supply faster and result in too much contention for the restricted resources of the DTMSN, so a proper data gathering scheme needs a trade off between the number of replica messages and network performance. In this paper, we propose a new data gathering protocol called DRADG (for Distance-aware Replica Adaptive Data Gathering protocol), which economizes network resource consumption through making use of a self-adapting algorithm to cut down the number of redundant replicas of messages, and achieves a good network performance by leveraging the delivery probabilities of the mobile sensors as main routing metrics. Simulation results have shown that the proposed DRADG protocol achieves comparable or higher message delivery ratios at the cost of the much lower transmission overhead than several current DTMSN data gathering schemes.

  3. Study of non-stoichiometric BaSrTiFeO3 oxide dedicated to semiconductor gas sensors

    International Nuclear Information System (INIS)

    Fasquelle, D.; Verbrugghe, N.; Deputier, S.

    2016-01-01

    Developing instrumentation systems compatible with the European RoHS directive (restriction of hazardous substances) to monitor our environment is of great interest for our society. Our research therefore aims at developing innovating integrated systems of detection dedicated to the characterization of various environmental exposures. These systems, which integrate new gas sensors containing lead-free oxides, are dedicated to the detection of flammable and toxic gases. We have firstly chosen to study semiconductor gas sensors implemented with lead-free oxides in view to develop RoHS devices. Therefore thick films deposited by spin-coating and screen-printing have been chosen for their robustness, ease to realize and ease to finally obtain cost-effective sensors. As crystalline defects and ionic vacancies are of great interest for gas detection, we have decided to study a non-stoichiometric composition of the BaSrTiFeO 3 sensible oxide. Nonstoichiometric BaSrTiFeO 3 lead-free oxide thick films were deposited by screen-printing on polycrystalline AFO 3 substrates covered by a layer of Ag-Pd acting as bottom electrode. The physical characterizations have revealed a crystalline structure mainly composed of BaTiO 3 pseudo-cubic phase and Ba 4 Ti 12 O 27 monoclinic phase for the powder, and a porous microstructure for the thick films. When compared to a BSTF thick film with a stoichiometric composition, a notable increase in the BSTF dielectric constant value was observed when taking into account of a similar microstructure and grain size. The loss tangent mean value varies more softly for the non-stoichiometric BaSrTiFeO 3 films than for the perovskite BSTF film as tanδ decreases from 0.45 to 0.04 when the frequency increases from 100 Hz to 1 MHz. (paper)

  4. An energy-efficient MAC protocol using dynamic queue management for delay-tolerant mobile sensor networks.

    Science.gov (United States)

    Li, Jie; Li, Qiyue; Qu, Yugui; Zhao, Baohua

    2011-01-01

    Conventional MAC protocols for wireless sensor network perform poorly when faced with a delay-tolerant mobile network environment. Characterized by a highly dynamic and sparse topology, poor network connectivity as well as data delay-tolerance, delay-tolerant mobile sensor networks exacerbate the severe power constraints and memory limitations of nodes. This paper proposes an energy-efficient MAC protocol using dynamic queue management (EQ-MAC) for power saving and data queue management. Via data transfers initiated by the target sink and the use of a dynamic queue management strategy based on priority, EQ-MAC effectively avoids untargeted transfers, increases the chance of successful data transmission, and makes useful data reach the target terminal in a timely manner. Experimental results show that EQ-MAC has high energy efficiency in comparison with a conventional MAC protocol. It also achieves a 46% decrease in packet drop probability, 79% increase in system throughput, and 25% decrease in mean packet delay.

  5. A Hybrid Fault-Tolerant Strategy for Severe Sensor Failure Scenarios in Late-Stage Offshore DFIG-WT

    Directory of Open Access Journals (Sweden)

    Wei Li

    2017-12-01

    Full Text Available As the phase current sensors and rotor speed/position sensor are prone to fail in the late stage of an offshore doubly-fed induction generator based wind turbine (DFIG-WT, this paper investigates a hybrid fault-tolerant strategy for a severe sensor failure scenario. The phase current sensors in the back-to-back (BTB converter and the speed/position sensor are in the faulty states simultaneously. Based on the 7th-order doubly-fed induction generator (DFIG dynamic state space model, the extended Kalman filter (EKF algorithm is applied for rotor speed and position estimation. In addition, good robustness of this sensorless control algorithm to system uncertainties and measurement disturbances is presented. Besides, a single DC-link current sensor based phase current reconstruction scheme is utilized for deriving the phase current information according to the switching states. A duty ratio adjustment strategy is proposed to avoid missing the sampling points in a switching period, which is simple to implement. Furthermore, the additional active time of the targeted nonzero switching states is complemented so that the reference voltage vector remains in the same position as that before duty ratio adjustment. The validity of the proposed hybrid fault-tolerant sensorless control strategy is demonstrated by simulation results in Matlab/Simulink2017a by considering harsh operating environments.

  6. Development of Electrical Capacitance Sensors for Accident Tolerant Fuel (ATF) Testing at the Transient Reactor Test (TREAT) Facility

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Maolong; Ryals, Matthew; Ali, Amir; Blandford, Edward; Jensen, Colby; Condie, Keith; Svoboda, John; O' Brien, Robert

    2016-08-01

    A variety of instruments are being developed and qualified to support the Accident Tolerant Fuels (ATF) program and future transient irradiations at the Transient Reactor Test (TREAT) facility at Idaho National Laboratory (INL). The University of New Mexico (UNM) is working with INL to develop capacitance-based void sensors for determining the timing of critical boiling phenomena in static capsule fuel testing and the volume-averaged void fraction in flow-boiling in-pile water loop fuel testing. The static capsule sensor developed at INL is a plate-type configuration, while UNM is utilizing a ring-type capacitance sensor. Each sensor design has been theoretically and experimentally investigated at INL and UNM. Experiments are being performed at INL in an autoclave to investigate the performance of these sensors under representative Pressurized Water Reactor (PWR) conditions in a static capsule. Experiments have been performed at UNM using air-water two-phase flow to determine the sensitivity and time response of the capacitance sensor under a flow boiling configuration. Initial measurements from the capacitance sensor have demonstrated the validity of the concept to enable real-time measurement of void fraction. The next steps include designing the cabling interface with the flow loop at UNM for Reactivity Initiated Accident (RIA) ATF testing at TREAT and further characterization of the measurement response for each sensor under varying conditions by experiments and modeling.

  7. Schottky barriers measurements through Arrhenius plots in gas sensors based on semiconductor films

    Directory of Open Access Journals (Sweden)

    F. Schipani

    2012-09-01

    Full Text Available The oxygen adsorption effects on the Schottky barriers height measurements for thick films gas sensors prepared with undoped nanometric SnO2 particles were studied. From electrical measurements, the characteristics of the intergranular potential barriers developed at intergrains were deduced. It is shown that the determination of effective activation energies from conduction vs. 1/temperature curves is not generally a correct manner to estimate barrier heights. This is due to gas adsorption/desorption during the heating and cooling processes, the assumption of emission over the barrier as the dominant conduction mechanism, and the possible oxygen diffusion into or out of the grains.

  8. Experimental evaluation of stable long term operation of semiconductor magnetic sensors at ITER relevant environment

    Czech Academy of Sciences Publication Activity Database

    Bolshakova, I.; Belyaev, S.; Bulavin, M.; Brudnyi, V.; Chekanov, V.; Coccorese, V.; Ďuran, Ivan; Gerasimov, S.; Holyaka, R.; Kargin, N.; Konopleva, R.; Kost, Ya.; Kuech, T.; Kulikov, S.; Makido, O.; Moreau, Ph.; Murari, A.; Quercia, A.; Shurygin, F.; Strikhanov, M.; Timoshyn, S.; Vasil’evskii, I.; Vinichenko, A.

    2015-01-01

    Roč. 55, č. 8 (2015), 083006-083006 ISSN 0029-5515 R&D Projects: GA ČR GAP205/10/2055 EU Projects: European Commission(XE) 633053 Institutional support: RVO:61389021 Keywords : Hall sensors * 3D probes * steady state * magnetic measurement instrumentation * tokamak Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.040, year: 2015 http://iopscience.iop.org/article/10.1088/0029-5515/55/8/083006/meta;jsessionid=534DB19F0353E8F68E6E558F2A324088.c2.iopscience.cld.iop.org

  9. Data Gathering in Delay Tolerant Wireless Sensor Networks Using a Ferry

    Directory of Open Access Journals (Sweden)

    Mariam Alnuaimi

    2015-10-01

    Full Text Available In delay tolerant WSNs mobile ferries can be used for collecting data from sensor nodes, especially in large-scale networks. Unlike data collection via multi-hop forwarding among the nodes, ferries travel across the sensing field and collect data from sensors. The advantage of using a ferry-based approach is that, it eliminates the need for multi-hop forwarding of data, and as a result energy consumption at the nodes is significantly reduced. However, this increases data delivery latency and as such might not be suitable for all applications. In this paper an efficient data collection algorithm using a ferry node is proposed while considering the overall ferry roundtrip travel time and the overall consumed energy in the network. To minimize the overall roundtrip travel time, we divided the sensing field area into virtual grids based on the assumed sensing range and assigned a checkpoint in each one. A Genetic Algorithm with weight metrics to solve the Travel Sales Man Problem (TSP and decide on an optimum path for the ferry to collect data is then used. We utilized our previously published node ranking clustering algorithm (NRCA in each virtual grid and in choosing the location for placing the ferry’s checkpoints. In NRCA the decision of selecting cluster heads is based on their residual energy and their distance from their associated checkpoint which acts as a temporary sink. We simulated the proposed algorithm in MATLAB and showed its performance in terms of the network lifetime, total energy consumption and the total travel time. Moreover, we showed through simulation that nonlinear trajectory achieves a better optimization in term of network lifetime, overall energy consumed and the roundtrip travel time of the ferry compared to linear predetermined trajectory. In additional to that, we compared the performance of your algorithm to other recent algorithms in terms of the network lifetime using same and different initial energy values.

  10. 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.

  11. Characterization study of an intensified complementary metal-oxide-semiconductor active pixel sensor

    Science.gov (United States)

    Griffiths, J. A.; Chen, D.; Turchetta, R.; Royle, G. J.

    2011-03-01

    An intensified CMOS active pixel sensor (APS) has been constructed for operation in low-light-level applications: a high-gain, fast-light decay image intensifier has been coupled via a fiber optic stud to a prototype "VANILLA" APS, developed by the UK based MI3 consortium. The sensor is capable of high frame rates and sparse readout. This paper presents a study of the performance parameters of the intensified VANILLA APS system over a range of image intensifier gain levels when uniformly illuminated with 520 nm green light. Mean-variance analysis shows the APS saturating around 3050 Digital Units (DU), with the maximum variance increasing with increasing image intensifier gain. The system's quantum efficiency varies in an exponential manner from 260 at an intensifier gain of 7.45 × 103 to 1.6 at a gain of 3.93 × 101. The usable dynamic range of the system is 60 dB for intensifier gains below 1.8 × 103, dropping to around 40 dB at high gains. The conclusion is that the system shows suitability for the desired application.

  12. Ultrasonic fingerprint sensor using a piezoelectric micromachined ultrasonic transducer array integrated with complementary metal oxide semiconductor electronics

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Y.; Fung, S.; Wang, Q.; Horsley, D. A. [Berkeley Sensor and Actuator Center, University of California, Davis, 1 Shields Avenue, Davis, California 95616 (United States); Tang, H.; Boser, B. E. [Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720 (United States); Tsai, J. M.; Daneman, M. [InvenSense, Inc., 1745 Technology Drive, San Jose, California 95110 (United States)

    2015-06-29

    This paper presents an ultrasonic fingerprint sensor based on a 24 × 8 array of 22 MHz piezoelectric micromachined ultrasonic transducers (PMUTs) with 100 μm pitch, fully integrated with 180 nm complementary metal oxide semiconductor (CMOS) circuitry through eutectic wafer bonding. Each PMUT is directly bonded to a dedicated CMOS receive amplifier, minimizing electrical parasitics and eliminating the need for through-silicon vias. The array frequency response and vibration mode-shape were characterized using laser Doppler vibrometry and verified via finite element method simulation. The array's acoustic output was measured using a hydrophone to be ∼14 kPa with a 28 V input, in reasonable agreement with predication from analytical calculation. Pulse-echo imaging of a 1D steel grating is demonstrated using electronic scanning of a 20 × 8 sub-array, resulting in 300 mV maximum received amplitude and 5:1 contrast ratio. Because the small size of this array limits the maximum image size, mechanical scanning was used to image a 2D polydimethylsiloxane fingerprint phantom (10 mm × 8 mm) at a 1.2 mm distance from the array.

  13. Extreme temperature robust optical sensor designs and fault-tolerant signal processing

    Science.gov (United States)

    Riza, Nabeel Agha [Oviedo, FL; Perez, Frank [Tujunga, CA

    2012-01-17

    Silicon Carbide (SiC) probe designs for extreme temperature and pressure sensing uses a single crystal SiC optical chip encased in a sintered SiC material probe. The SiC chip may be protected for high temperature only use or exposed for both temperature and pressure sensing. Hybrid signal processing techniques allow fault-tolerant extreme temperature sensing. Wavelength peak-to-peak (or null-to-null) collective spectrum spread measurement to detect wavelength peak/null shift measurement forms a coarse-fine temperature measurement using broadband spectrum monitoring. The SiC probe frontend acts as a stable emissivity Black-body radiator and monitoring the shift in radiation spectrum enables a pyrometer. This application combines all-SiC pyrometry with thick SiC etalon laser interferometry within a free-spectral range to form a coarse-fine temperature measurement sensor. RF notch filtering techniques improve the sensitivity of the temperature measurement where fine spectral shift or spectrum measurements are needed to deduce temperature.

  14. Indirect adaptive fuzzy fault-tolerant tracking control for MIMO nonlinear systems with actuator and sensor failures.

    Science.gov (United States)

    Bounemeur, Abdelhamid; Chemachema, Mohamed; Essounbouli, Najib

    2018-05-10

    In this paper, an active fuzzy fault tolerant tracking control (AFFTTC) scheme is developed for a class of multi-input multi-output (MIMO) unknown nonlinear systems in the presence of unknown actuator faults, sensor failures and external disturbance. The developed control scheme deals with four kinds of faults for both sensors and actuators. The bias, drift, and loss of accuracy additive faults are considered along with the loss of effectiveness multiplicative fault. A fuzzy adaptive controller based on back-stepping design is developed to deal with actuator failures and unknown system dynamics. However, an additional robust control term is added to deal with sensor faults, approximation errors, and external disturbances. Lyapunov theory is used to prove the stability of the closed loop system. Numerical simulations on a quadrotor are presented to show the effectiveness of the proposed approach. Copyright © 2018 ISA. Published by Elsevier Ltd. All rights reserved.

  15. An Energy-Efficient MAC Protocol Using Dynamic Queue Management for Delay-Tolerant Mobile Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yugui Qu

    2011-02-01

    Full Text Available Conventional MAC protocols for wireless sensor network perform poorly when faced with a delay-tolerant mobile network environment. Characterized by a highly dynamic and sparse topology, poor network connectivity as well as data delay-tolerance, delay-tolerant mobile sensor networks exacerbate the severe power constraints and memory limitations of nodes. This paper proposes an energy-efficient MAC protocol using dynamic queue management (EQ-MAC for power saving and data queue management. Via data transfers initiated by the target sink and the use of a dynamic queue management strategy based on priority, EQ-MAC effectively avoids untargeted transfers, increases the chance of successful data transmission, and makes useful data reach the target terminal in a timely manner. Experimental results show that EQ-MAC has high energy efficiency in comparison with a conventional MAC protocol. It also achieves a 46% decrease in packet drop probability, 79% increase in system throughput, and 25% decrease in mean packet delay.

  16. CONTEXT-CAPTURE MULTI-VALUED DECISION FUSION WITH FAULT TOLERANT CAPABILITY FOR WIRELESS SENSOR NETWORKS

    OpenAIRE

    Jun Wu; Shigeru Shimamoto

    2011-01-01

    Wireless sensor networks (WSNs) are usually utilized to perform decision fusion of event detection. Current decision fusion schemes are based on binary valued decision and do not consider bursty contextcapture. However, bursty context and multi-valued data are important characteristics of WSNs. One on hand, the local decisions from sensors usually have bursty and contextual characteristics. Fusion center must capture the bursty context information from the sensors. On the other hand, in pract...

  17. A High Temperature-Tolerant and Radiation-Resistant In-Core Neutron Sensor for Advanced Reactors. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Lei [The Ohio State Univ., Columbus, OH (United States); Miller, Don [The Ohio State Univ., Columbus, OH (United States)

    2015-01-23

    The objectives of this project are to develop a small and reliable gallium nitride (GaN) neutron sensor that is capable of withstanding high neutron fluence and high temperature, isolating gamma background, and operating in a wide dynamic range. The first objective will be the understanding of the fundamental materials properties and electronic response of a GaN semiconductor materials and device in an environment of high temperature and intense neutron field. To achieve such goal, an in-situ study of electronic properties of GaN device such as I-V, leakage current, and charge collection efficiency (CCE) in high temperature using an external neutron beam will be designed and implemented. We will also perform in-core irradiation of GaN up to the highest yet fast neutron fluence and an off-line performance evaluation.

  18. A High Temperature-Tolerant and Radiation-Resistant In-Core Neutron Sensor for Advanced Reactors. Final report

    International Nuclear Information System (INIS)

    Cao, Lei; Miller, Don

    2015-01-01

    The objectives of this project are to develop a small and reliable gallium nitride (GaN) neutron sensor that is capable of withstanding high neutron fluence and high temperature, isolating gamma background, and operating in a wide dynamic range. The first objective will be the understanding of the fundamental materials properties and electronic response of a GaN semiconductor materials and device in an environment of high temperature and intense neutron field. To achieve such goal, an in-situ study of electronic properties of GaN device such as I-V, leakage current, and charge collection efficiency (CCE) in high temperature using an external neutron beam will be designed and implemented. We will also perform in-core irradiation of GaN up to the highest yet fast neutron fluence and an off-line performance evaluation.

  19. A Soft Sensor-Based Fault-Tolerant Control on the Air Fuel Ratio of Spark-Ignition Engines

    Directory of Open Access Journals (Sweden)

    Yu-Jia Zhai

    2017-01-01

    Full Text Available The air/fuel ratio (AFR regulation for spark-ignition (SI engines has been an essential and challenging control problem for engineers in the automotive industry. The feed-forward and feedback scheme has been investigated in both academic research and industrial application. The aging effect can often cause an AFR sensor fault in the feedback loop, and the AFR control performance will degrade consequently. In this research, a new control scheme on AFR with fault-tolerance is proposed by using an artificial neural network model based on fault detection and compensation, which can provide the satisfactory AFR regulation performance at the stoichiometric value for the combustion process, given a certain level of misreading of the AFR sensor.

  20. Fault tolerant attitude control for small unmanned aircraft systems equipped with an airflow sensor array.

    Science.gov (United States)

    Shen, H; Xu, Y; Dickinson, B T

    2014-11-18

    Inspired by sensing strategies observed in birds and bats, a new attitude control concept of directly using real-time pressure and shear stresses has recently been studied. It was shown that with an array of onboard airflow sensors, small unmanned aircraft systems can promptly respond to airflow changes and improve flight performances. In this paper, a mapping function is proposed to compute aerodynamic moments from the real-time pressure and shear data in a practical and computationally tractable formulation. Since many microscale airflow sensors are embedded on the small unmanned aircraft system surface, it is highly possible that certain sensors may fail. Here, an adaptive control system is developed that is robust to sensor failure as well as other numerical mismatches in calculating real-time aerodynamic moments. The advantages of the proposed method are shown in the following simulation cases: (i) feedback pressure and wall shear data from a distributed array of 45 airflow sensors; (ii) 50% failure of the symmetrically distributed airflow sensor array; and (iii) failure of all the airflow sensors on one wing. It is shown that even if 50% of the airflow sensors have failures, the aircraft is still stable and able to track the attitude commands.

  1. Distributed sensor and actuator reconfiguration for fault-tolerant networked control systems

    NARCIS (Netherlands)

    Herdeiro Teixeira, A.M.; Araujo, Jose; Sandberg, Henrik; Johansson, Karl H.

    2017-01-01

    In this paper, we address the problem of distributed reconfiguration of networked control systems upon the removal of misbehaving sensors and actuators. In particular, we consider systems with redundant sensors and actuators cooperating to recover from faults. Reconfiguration is performed while

  2. Real-time two-dimensional imaging of potassium ion distribution using an ion semiconductor sensor with charged coupled device technology.

    Science.gov (United States)

    Hattori, Toshiaki; Masaki, Yoshitomo; Atsumi, Kazuya; Kato, Ryo; Sawada, Kazuaki

    2010-01-01

    Two-dimensional real-time observation of potassium ion distributions was achieved using an ion imaging device based on charge-coupled device (CCD) and metal-oxide semiconductor technologies, and an ion selective membrane. The CCD potassium ion image sensor was equipped with an array of 32 × 32 pixels (1024 pixels). It could record five frames per second with an area of 4.16 × 4.16 mm(2). Potassium ion images were produced instantly. The leaching of potassium ion from a 3.3 M KCl Ag/AgCl reference electrode was dynamically monitored in aqueous solution. The potassium ion selective membrane on the semiconductor consisted of plasticized poly(vinyl chloride) (PVC) with bis(benzo-15-crown-5). The addition of a polyhedral oligomeric silsesquioxane to the plasticized PVC membrane greatly improved adhesion of the membrane onto Si(3)N(4) of the semiconductor surface, and the potential response was stabilized. The potential response was linear from 10(-2) to 10(-5) M logarithmic concentration of potassium ion. The selectivity coefficients were K(K(+),Li(+))(pot) = 10(-2.85), K(K(+),Na(+))(pot) = 10(-2.30), K(K(+),Rb(+))(pot) =10(-1.16), and K(K(+),Cs(+))(pot) = 10(-2.05).

  3. Semiconductor Ceramic Mn0.5Fe1.5O3-Fe2O3 from Natural Minerals as Ethanol Gas Sensors

    Science.gov (United States)

    Aliah, H.; Syarif, D. G.; Iman, R. N.; Sawitri, A.; Sanjaya WS, M.; Nurul Subkhi, M.; Pitriana, P.

    2018-05-01

    In this research, Mn and Fe-based ceramic gas sensing were fabricated and characterized. This research used natural mineral which is widely available in Indonesia and intended to observe the characteristics of Mn and Fe-based semiconducting material. Fabricating process of the thick films started by synthesizing the ceramic powder of Fe(OH)3 and Mn oxide material using the precipitation method. The deposition from precipitation method previously was calcined at a temperature of 800 °C to produce nanoparticle powder. Nanoparticle powder that contains Mn and Fe oxide was mixed with an organic vehicle (OV) to produce a paste. Then, the paste was layered on the alumina substrate by using the screen printing method. XRD method was utilized to characterize the thick film crystal structure that has been produced. XRD spectra showed that the ceramic layer was formed from the solid Mn0.5Fe1.5O3 (bixbyite) and Fe2O3. In addition, the electrical properties (resistance) examination was held in the room that contains air and ethanol to determine the sensor sensitivity of ethanol gas. The sensor resistance decreases as the ethanol gas was added, showing that the sensor was sensitive to ethanol gas and an n-type semiconductor. Gas sensor exhibit sensitive characterization of ethanol gas on the concentration of (100 to 300) ppm at a temperature of (150 to 200) °C. This showed that the Mn0.5Fe1.5O3-Fe2O3 ceramic semiconductor could be utilized as the ethanol gas detector.

  4. An Immune Cooperative Particle Swarm Optimization Algorithm for Fault-Tolerant Routing Optimization in Heterogeneous Wireless Sensor Networks

    Directory of Open Access Journals (Sweden)

    Yifan Hu

    2012-01-01

    Full Text Available The fault-tolerant routing problem is important consideration in the design of heterogeneous wireless sensor networks (H-WSNs applications, and has recently been attracting growing research interests. In order to maintain k disjoint communication paths from source sensors to the macronodes, we present a hybrid routing scheme and model, in which multiple paths are calculated and maintained in advance, and alternate paths are created once the previous routing is broken. Then, we propose an immune cooperative particle swarm optimization algorithm (ICPSOA in the model to provide the fast routing recovery and reconstruct the network topology for path failure in H-WSNs. In the ICPSOA, mutation direction of the particle is determined by multi-swarm evolution equation, and its diversity is improved by immune mechanism, which can enhance the capacity of global search and improve the converging rate of the algorithm. Then we validate this theoretical model with simulation results. The results indicate that the ICPSOA-based fault-tolerant routing protocol outperforms several other protocols due to its capability of fast routing recovery mechanism, reliable communications, and prolonging the lifetime of WSNs.

  5. 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

  6. Delay/Disruption Tolerant Network-Based Message Forwarding for a River Pollution Monitoring Wireless Sensor Network Application.

    Science.gov (United States)

    Velásquez-Villada, Carlos; Donoso, Yezid

    2016-03-25

    Communications from remote areas that may be of interest is still a problem. Many innovative projects applied to remote sites face communications difficulties. The GOLDFISH project was an EU-funded project for river pollution monitoring in developing countries. It had several sensor clusters, with floating WiFi antennas, deployed along a downstream river's course. Sensor clusters sent messages to a Gateway installed on the riverbank. This gateway sent the messages, through a backhaul technology, to an Internet server where data was aggregated over a map. The communication challenge in this scenario was produced by the antennas' movement and network backhaul availability. Since the antennas were floating on the river, communications could be disrupted at any time. Also, 2G/3G availability near the river was not constant. For non-real-time applications, we propose a Delay/Disruption Tolerant Network (DTN)-based solution where all nodes have persistent storage capabilities and DTN protocols to be able to wait minutes or hours to transmit. A mechanical backhaul will periodically visit the river bank where the gateway is installed and it will automatically collect sensor data to be carried to an Internet-covered spot. The proposed forwarding protocol delivers around 98% of the messages for this scenario, performing better than other well-known DTN routing protocols.

  7. Delay/Disruption Tolerant Network-Based Message Forwarding for a River Pollution Monitoring Wireless Sensor Network Application

    Directory of Open Access Journals (Sweden)

    Carlos Velásquez-Villada

    2016-03-01

    Full Text Available Communications from remote areas that may be of interest is still a problem. Many innovative projects applied to remote sites face communications difficulties. The GOLDFISH project was an EU-funded project for river pollution monitoring in developing countries. It had several sensor clusters, with floating WiFi antennas, deployed along a downstream river’s course. Sensor clusters sent messages to a Gateway installed on the riverbank. This gateway sent the messages, through a backhaul technology, to an Internet server where data was aggregated over a map. The communication challenge in this scenario was produced by the antennas’ movement and network backhaul availability. Since the antennas were floating on the river, communications could be disrupted at any time. Also, 2G/3G availability near the river was not constant. For non-real-time applications, we propose a Delay/Disruption Tolerant Network (DTN-based solution where all nodes have persistent storage capabilities and DTN protocols to be able to wait minutes or hours to transmit. A mechanical backhaul will periodically visit the river bank where the gateway is installed and it will automatically collect sensor data to be carried to an Internet-covered spot. The proposed forwarding protocol delivers around 98% of the messages for this scenario, performing better than other well-known DTN routing protocols.

  8. Practical Use Technique of Sensor

    International Nuclear Information System (INIS)

    Hwang, Gyu Seop

    1985-11-01

    This book tells of practical use technology of sensor, introducing the recent trend of sensor for electronic industry, IC temperature sensor, radiation temperature sensor of surface acoustic wave, optical fiber temperature sensor, a polyelectrolyte film humidity sensor, semiconductor pressure sensor for industrial instrumentation, silicon integration pressure sensor, thick film humidity sensor and its application, photo sensor reflection type, and color sensor. It also deals with sensor for FA, sensor for a robot and sensor for the chemical industry.

  9. Practical Use Technique of Sensor

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, Gyu Seop

    1985-11-15

    This book tells of practical use technology of sensor, introducing the recent trend of sensor for electronic industry, IC temperature sensor, radiation temperature sensor of surface acoustic wave, optical fiber temperature sensor, a polyelectrolyte film humidity sensor, semiconductor pressure sensor for industrial instrumentation, silicon integration pressure sensor, thick film humidity sensor and its application, photo sensor reflection type, and color sensor. It also deals with sensor for FA, sensor for a robot and sensor for the chemical industry.

  10. A Hybrid Sensor Based Backstepping Control Approach with its Application to Fault-Tolerant Flight Control

    NARCIS (Netherlands)

    Sun, L.G.; De Visser, C.C.; Chu, Q.P.; Falkena, W.

    2013-01-01

    Recently, an incremental type sensor based backstepping (SBB) control approach, based on singular perturbation theory and Tikhonov’s theorem, has been proposed. This Lyapunov function based method uses measurements of control variables and less model knowledge, and it is not susceptible to the model

  11. A Community-Based Event Delivery Protocol in Publish/Subscribe Systems for Delay Tolerant Sensor Networks

    Directory of Open Access Journals (Sweden)

    Haigang Gong

    2009-09-01

    Full Text Available The basic operation of a Delay Tolerant Sensor Network (DTSN is to finish pervasive data gathering in networks with intermittent connectivity, while the publish/subscribe (Pub/Sub for short paradigm is used to deliver events from a source to interested clients in an asynchronous way. Recently, extension of Pub/Sub systems in DTSNs has become a promising research topic. However, due to the unique frequent partitioning characteristic of DTSNs, extension of a Pub/Sub system in a DTSN is a considerably difficult and challenging problem, and there are no good solutions to this problem in published works. To ad apt Pub/Sub systems to DTSNs, we propose CED, a community-based event delivery protocol. In our design, event delivery is based on several unchanged communities, which are formed by sensor nodes in the network according to their connectivity. CED consists of two components: event delivery and queue management. In event delivery, events in a community are delivered to mobile subscribers once a subscriber comes into the community, for improving the data delivery ratio. The queue management employs both the event successful delivery time and the event survival time to decide whether an event should be delivered or dropped for minimizing the transmission overhead. The effectiveness of CED is demonstrated through comprehensive simulation studies.

  12. A community-based event delivery protocol in publish/subscribe systems for delay tolerant sensor networks.

    Science.gov (United States)

    Liu, Nianbo; Liu, Ming; Zhu, Jinqi; Gong, Haigang

    2009-01-01

    The basic operation of a Delay Tolerant Sensor Network (DTSN) is to finish pervasive data gathering in networks with intermittent connectivity, while the publish/subscribe (Pub/Sub for short) paradigm is used to deliver events from a source to interested clients in an asynchronous way. Recently, extension of Pub/Sub systems in DTSNs has become a promising research topic. However, due to the unique frequent partitioning characteristic of DTSNs, extension of a Pub/Sub system in a DTSN is a considerably difficult and challenging problem, and there are no good solutions to this problem in published works. To ad apt Pub/Sub systems to DTSNs, we propose CED, a community-based event delivery protocol. In our design, event delivery is based on several unchanged communities, which are formed by sensor nodes in the network according to their connectivity. CED consists of two components: event delivery and queue management. In event delivery, events in a community are delivered to mobile subscribers once a subscriber comes into the community, for improving the data delivery ratio. The queue management employs both the event successful delivery time and the event survival time to decide whether an event should be delivered or dropped for minimizing the transmission overhead. The effectiveness of CED is demonstrated through comprehensive simulation studies.

  13. 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.

  14. Novel Dry-Type Glucose Sensor Based on a Metal-Oxide-Semiconductor Capacitor Structure with Horseradish Peroxidase + Glucose Oxidase Catalyzing Layer

    Science.gov (United States)

    Lin, Jing-Jenn; Wu, You-Lin; Hsu, Po-Yen

    2007-10-01

    In this paper, we present a novel dry-type glucose sensor based on a metal-oxide-semiconductor capacitor (MOSC) structure using SiO2 as a gate dielectric in conjunction with a horseradish peroxidase (HRP) + glucose oxidase (GOD) catalyzing layer. The tested glucose solution was dropped directly onto the window opened on the SiO2 layer, with a coating of HRP + GOD catalyzing layer on top of the gate dielectric. From the capacitance-voltage (C-V) characteristics of the sensor, we found that the glucose solution can induce an inversion layer on the silicon surface causing a gate leakage current flowing along the SiO2 surface. The gate current changes Δ I before and after the drop of glucose solution exhibits a near-linear relationship with increasing glucose concentration. The Δ I sensitivity is about 1.76 nA cm-2 M-1, and the current is quite stable 20 min after the drop of the glucose solution is tested.

  15. An ultrasensitive method of real time pH monitoring with complementary metal oxide semiconductor image sensor.

    Science.gov (United States)

    Devadhasan, Jasmine Pramila; Kim, Sanghyo

    2015-02-09

    CMOS sensors are becoming a powerful tool in the biological and chemical field. In this work, we introduce a new approach on quantifying various pH solutions with a CMOS image sensor. The CMOS image sensor based pH measurement produces high-accuracy analysis, making it a truly portable and user friendly system. pH indicator blended hydrogel matrix was fabricated as a thin film to the accurate color development. A distinct color change of red, green and blue (RGB) develops in the hydrogel film by applying various pH solutions (pH 1-14). The semi-quantitative pH evolution was acquired by visual read out. Further, CMOS image sensor absorbs the RGB color intensity of the film and hue value converted into digital numbers with the aid of an analog-to-digital converter (ADC) to determine the pH ranges of solutions. Chromaticity diagram and Euclidean distance represent the RGB color space and differentiation of pH ranges, respectively. This technique is applicable to sense the various toxic chemicals and chemical vapors by situ sensing. Ultimately, the entire approach can be integrated into smartphone and operable with the user friendly manner. Copyright © 2014 Elsevier B.V. All rights reserved.

  16. 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.

  17. Functionalized vertically aligned ZnO nanorods for application in electrolyte-insulator-semiconductor based pH sensors and label-free immuno-sensors

    International Nuclear Information System (INIS)

    Kumar, Narendra; Senapati, Sujata; Kumar, Jitendra; Panda, Siddhartha; Kumar, Satyendra

    2016-01-01

    Vertically aligned ZnO nanorods were grown on a SiO 2 /Si surface by optimization of the temperature and atmosphere for annealing of the seed. The seed layer annealed at 500 °C in vacuum provided well separated and uniform seeds which also provided the best condition to get densely packed, uniformly distributed, and vertically aligned nanorods. These nanorods grown on the substrates were used to fabricate electrolyte-insulator-semiconductor (EIS) devices for pH sensing. Etching of ZnO at acidic pH prevents the direct use of nanorods for pH sensing. Therefore, the nanorods functionalised with 3-aminopropyltriethoxysilane (APTES) were utilized for pH sensing and showed the pH sensitivity of 50.1 mV/pH. APTES is also known to be used as a linker to immobilize biomolecules (such as antibodies). The EIS device with APTES functionalized nanorods was used for the label free detection of prostate-specific antigen (PSA). Finally, voltage shifts of 23 mV and 35 mV were observed with PSA concentrations of 1 ng/ml and 100 ng/ml, respectively. (paper)

  18. Short-range remote spectral sensor using mid-infrared semiconductor lasers with orthogonal code-division multiplexing approach

    Science.gov (United States)

    Morbi, Zulfikar; Ho, D. B.; Ren, H.-W.; Le, Han Q.; Pei, Shin Shem

    2002-09-01

    Demonstration of short-range multispectral remote sensing, using 3 to 4-micrometers mid- infrared Sb semiconductor lasers based on code-division multiplexing (CDM) architecture, is described. The system is built on a principle similar to intensity- modulated/direct-detection optical-CDMA for communications, but adapted for sensing with synchronous, orthogonal codes to distinguish different wavelength channels with zero interchannel correlation. The concept is scalable for any number of channels, and experiments with a two-wavelength system are conducted. The CDM-signal processing yielded a white-Gaussian-like system noise that is found to be near the theoretical level limited by the detector fundamental intrinsic noise. With sub-mW transmitter average power, the system was able to detect an open-air acetylene gas leak of 10-2 STP ft3/hr from 10-m away with time-varying, random, noncooperative backscatters. A similar experiment detected and positively distinguished hydrocarbon oil contaminants on water from bio-organic oils and detergents. Projection for more advanced systems suggests a multi-kilometer-range capability for watt-level transmitters, and hundreds of wavelength channels can also be accommodated for active hyperspectral remote sensing application.

  19. Pseudo 2-transistor active pixel sensor using an n-well/gate-tied p-channel metal oxide semiconductor field eeffect transistor-type photodetector with built-in transfer gate

    Science.gov (United States)

    Seo, Sang-Ho; Seo, Min-Woong; Kong, Jae-Sung; Shin, Jang-Kyoo; Choi, Pyung

    2008-11-01

    In this paper, a pseudo 2-transistor active pixel sensor (APS) has been designed and fabricated by using an n-well/gate-tied p-channel metal oxide semiconductor field effect transistor (PMOSFET)-type photodetector with built-in transfer gate. The proposed sensor has been fabricated using a 0.35 μm 2-poly 4-metal standard complementary metal oxide semiconductor (CMOS) logic process. The pseudo 2-transistor APS consists of two NMOSFETs and one photodetector which can amplify the generated photocurrent. The area of the pseudo 2-transistor APS is 7.1 × 6.2 μm2. The sensitivity of the proposed pixel is 49 lux/(V·s). By using this pixel, a smaller pixel area and a higher level of sensitivity can be realized when compared with a conventional 3-transistor APS which uses a pn junction photodiode.

  20. Modeling the dark current histogram induced by gold contamination in complementary-metal-oxide-semiconductor image sensors

    Energy Technology Data Exchange (ETDEWEB)

    Domengie, F., E-mail: florian.domengie@st.com; Morin, P. [STMicroelectronics Crolles 2 (SAS), 850 Rue Jean Monnet, 38926 Crolles Cedex (France); Bauza, D. [CNRS, IMEP-LAHC - Grenoble INP, Minatec: 3, rue Parvis Louis Néel, CS 50257, 38016 Grenoble Cedex 1 (France)

    2015-07-14

    We propose a model for dark current induced by metallic contamination in a CMOS image sensor. Based on Shockley-Read-Hall kinetics, the expression of dark current proposed accounts for the electric field enhanced emission factor due to the Poole-Frenkel barrier lowering and phonon-assisted tunneling mechanisms. To that aim, we considered the distribution of the electric field magnitude and metal atoms in the depth of the pixel. Poisson statistics were used to estimate the random distribution of metal atoms in each pixel for a given contamination dose. Then, we performed a Monte-Carlo-based simulation for each pixel to set the number of metal atoms the pixel contained and the enhancement factor each atom underwent, and obtained a histogram of the number of pixels versus dark current for the full sensor. Excellent agreement with the dark current histogram measured on an ion-implanted gold-contaminated imager has been achieved, in particular, for the description of the distribution tails due to the pixel regions in which the contaminant atoms undergo a large electric field. The agreement remains very good when increasing the temperature by 15 °C. We demonstrated that the amplification of the dark current generated for the typical electric fields encountered in the CMOS image sensors, which depends on the nature of the metal contaminant, may become very large at high electric field. The electron and hole emissions and the resulting enhancement factor are described as a function of the trap characteristics, electric field, and temperature.

  1. 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.

  2. A new portable sulfide monitor with a zinc-oxide semiconductor sensor for daily use and field study.

    Science.gov (United States)

    Tanda, Naoko; Washio, Jumpei; Ikawa, Kyoko; Suzuki, Kengo; Koseki, Takeyoshi; Iwakura, Masaki

    2007-07-01

    For measuring oral malodor in daily clinical practice and in field study, we developed and evaluated a highly sensitive portable monitor system. We examined sensitivity and specificity of the sensor for volatile sulfur compounds (VSC) and obstructive gases, such as ethanol, acetone, and acetaldehyde. Each mouth air provided by 46 people was measured by this monitor, gas chromatography (GC), and olfactory panel and compared with each other. Based on the result, we used the monitor for mass health examination of a rural town with standardized measuring. The sensor detected hydrogen sulfide, methyl mercaptan, and dimethyl sulfide with 10-1000 times higher sensitivity than the other gases. The monitor's specificity was significantly improved by a VSC-selective filter. There were significant correlations between VSC concentration by the sulfide monitor and by GC, and by organoleptic score. Thirty-six percent of 969 examinees had oral malodor in a rural town. Seventy-eight percent of 969 examinees were motivated to take care of their oral condition by oral malodor measuring with the monitor. The portable sulfide monitor was useful to promote oral health care not only in clinics, but also in field study. The simple and quick operation system and the standardized measuring make it one of parameters of oral condition.

  3. Monolithic integration of a silicon nanowire field-effect transistors array on a complementary metal-oxide semiconductor chip for biochemical sensor applications.

    Science.gov (United States)

    Livi, Paolo; Kwiat, Moria; Shadmani, Amir; Pevzner, Alexander; Navarra, Giulio; Rothe, Jörg; Stettler, Alexander; Chen, Yihui; Patolsky, Fernando; Hierlemann, Andreas

    2015-10-06

    We present a monolithic complementary metal-oxide semiconductor (CMOS)-based sensor system comprising an array of silicon nanowire field-effect transistors (FETs) and the signal-conditioning circuitry on the same chip. The silicon nanowires were fabricated by chemical vapor deposition methods and then transferred to the CMOS chip, where Ti/Pd/Ti contacts had been patterned via e-beam lithography. The on-chip circuitry measures the current flowing through each nanowire FET upon applying a constant source-drain voltage. The analog signal is digitized on chip and then transmitted to a receiving unit. The system has been successfully fabricated and tested by acquiring I-V curves of the bare nanowire-based FETs. Furthermore, the sensing capabilities of the complete system have been demonstrated by recording current changes upon nanowire exposure to solutions of different pHs, as well as by detecting different concentrations of Troponin T biomarkers (cTnT) through antibody-functionalized nanowire FETs.

  4. Structural Properties and Sensing Performance of CeYxOy Sensing Films for Electrolyte-Insulator-Semiconductor pH Sensors.

    Science.gov (United States)

    Pan, Tung-Ming; Wang, Chih-Wei; Chen, Ching-Yi

    2017-06-07

    In this study we developed CeY x O y sensing membranes displaying super-Nernstian pH-sensitivity for use in electrolyte-insulator-semiconductor (EIS) pH sensors. We examined the effect of thermal annealing on the structural properties and sensing characteristics of the CeY x O y sensing membranes deposited through reactive co-sputtering onto Si substrates. X-ray diffraction, atomic force microscopy, and X-ray photoelectron spectroscopy revealed the structural, morphological, and chemical features, respectively, of the CeY x O y films after their annealing at 600-900 °C. Among the tested systems, the CeY x O y EIS device prepared with annealing at 800 °C exhibited the highest sensitivity (78.15 mV/pH), the lowest hysteresis voltage (1.4 mV), and the lowest drift rate (0.85 mV/h). Presumably, these annealing conditions optimized the stoichiometry of (CeY)O 2 in the film and its surface roughness while suppressing silicate formation at the CeY x O y -Si interface. We attribute the super-Nernstian pH-sensitivity to the incorporation of Y ions in the Ce framework, thereby decreasing the oxidation state Ce (Ce 4+  → Ce 3+ ) and resulting in less than one electron transferred per proton in the redox reaction.

  5. Sensors

    CERN Document Server

    Pigorsch, Enrico

    1997-01-01

    This is the 5th edition of the Metra Martech Directory "EUROPEAN CENTRES OF EXPERTISE - SENSORS." The entries represent a survey of European sensors development. The new edition contains 425 detailed profiles of companies and research institutions in 22 countries. This is reflected in the diversity of sensors development programmes described, from sensors for physical parameters to biosensors and intelligent sensor systems. We do not claim that all European organisations developing sensors are included, but this is a good cross section from an invited list of participants. If you see gaps or omissions, or would like your organisation to be included, please send details. The data base invites the formation of effective joint ventures by identifying and providing access to specific areas in which organisations offer collaboration. This issue is recognised to be of great importance and most entrants include details of collaboration offered and sought. We hope the directory on Sensors will help you to find the ri...

  6. Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Jensen, H. [PBI-Dansensor A/S (Denmark); Toft Soerensen, O. [Risoe National Lab., Materials Research Dept. (Denmark)

    1999-10-01

    A new type of ceramic oxygen sensors based on semiconducting oxides was developed in this project. The advantage of these sensors compared to standard ZrO{sub 2} sensors is that they do not require a reference gas and that they can be produced in small sizes. The sensor design and the techniques developed for production of these sensors are judged suitable by the participating industry for a niche production of a new generation of oxygen sensors. Materials research on new oxygen ion conducting conductors both for applications in oxygen sensors and in fuel was also performed in this project and finally a new process was developed for fabrication of ceramic tubes by dip-coating. (EHS)

  7. Analysis of a Statistical Relationship Between Dose and Error Tallies in Semiconductor Digital Integrated Circuits for Application to Radiation Monitoring Over a Wireless Sensor Network

    Science.gov (United States)

    Colins, Karen; Li, Liqian; Liu, Yu

    2017-05-01

    Mass production of widely used semiconductor digital integrated circuits (ICs) has lowered unit costs to the level of ordinary daily consumables of a few dollars. It is therefore reasonable to contemplate the idea of an engineered system that consumes unshielded low-cost ICs for the purpose of measuring gamma radiation dose. Underlying the idea is the premise of a measurable correlation between an observable property of ICs and radiation dose. Accumulation of radiation-damage-induced state changes or error events is such a property. If correct, the premise could make possible low-cost wide-area radiation dose measurement systems, instantiated as wireless sensor networks (WSNs) with unshielded consumable ICs as nodes, communicating error events to a remote base station. The premise has been investigated quantitatively for the first time in laboratory experiments and related analyses performed at the Canadian Nuclear Laboratories. State changes or error events were recorded in real time during irradiation of samples of ICs of different types in a 60Co gamma cell. From the error-event sequences, empirical distribution functions of dose were generated. The distribution functions were inverted and probabilities scaled by total error events, to yield plots of the relationship between dose and error tallies. Positive correlation was observed, and discrete functional dependence of dose quantiles on error tallies was measured, demonstrating the correctness of the premise. The idea of an engineered system that consumes unshielded low-cost ICs in a WSN, for the purpose of measuring gamma radiation dose over wide areas, is therefore tenable.

  8. Performance of new radiation tolerant thin n-in-p Silicon pixel sensors for the CMS experiment at High Luminosity LHC

    CERN Document Server

    Dalla Betta, G.F; Darbo, G; Dinardo, Mauro; Giacomini, G; Menasce, Dario; Meschini, Marco; Messineo, Alberto; Moroni, Luigi; Rivera, Ryan Allen; Ronchin, S; Uplegger, Lorenzo; Viliani, Lorenzo; Zoi, Irene; Zuolo, Davide

    2017-01-01

    The High Luminosity upgrade of the CERN-LHC (HL-LHC) demands for a new high-radiation tolerant solid-state pixel sensor capable of surviving fluencies up to a few 10$^{16}$ particles/cm$^2$ at $\\sim$3 cm from the interaction point. To this extent the INFN ATLAS-CMS joint research activity in collaboration with Fondazione Bruno Kessler-FBK, is aiming at the development of thin n-in-p type pixel sensors for the HL-LHC. The R and D covers both planar and single-sided 3D columnar pixel devices made with the Si-Si Direct Wafer Bonding technique, which allows for the production of sensors with 100~$\\mu {\\rm m}$ and 130~$\\mu {\\rm m}$ active thickness for planars, and 130~$\\mu {\\rm m}$ for 3D sensors, the thinnest ones ever produced so far. First prototypes of hybrid modules bump-bonded to the present CMS readout chip have been tested in beam tests. Preliminary results on their performance before and after irradiation are presented.

  9. DiNAMAC : A disruption tolerant, reinforcement learning-based Mac protocol for implantable body sensor networks

    NARCIS (Netherlands)

    Karuppiah Ramachandran, Vignesh Raja; Le Viet Duc, L Duc; Meratnia, Nirvana; Havinga, Paul J.M.

    Ongoing advancements in Body Sensor Networks (BSN) have enabled continuous health monitoring of chronically ill patients, with the use of implantable and body worn sensor nodes. Inevitable day-to-day activities such as walking, running, and sleeping cause severe disruptions in the wireless link

  10. 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.

  11. 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.

  12. 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

  13. Sensor

    OpenAIRE

    Gleeson, Helen; Dierking, Ingo; Grieve, Bruce; Woodyatt, Christopher; Brimicombe, Paul

    2015-01-01

    An electrical temperature sensor (10) comprises a liquid crystalline material (12). First and second electrically conductive contacts (14), (16), having a spaced relationship there between, contact the liquid crystalline material (12). An electric property measuring device is electrically connected to the first and second contacts (14), (16) and is arranged to measure an electric property of the liquid crystalline material (12). The liquid crystalline material (12) has a transition temperatur...

  14. 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.

  15. Recent progress of the RD50 Collaboration – Development of radiation tolerant tracking detectors

    CERN Document Server

    Moll, M

    2014-01-01

    The CERN RD50 Collaboration "Radiation hard semiconductor devices for high luminosity col- liders" is undertaking a massive R&D; programme across High Energy Physics (HEP) Experi- ments boundaries to develop silicon sensors with increased radiation tolerance. Highest priority is to provide concepts and prototypes of high performance silicon sensors for the High-Luminosity Large Hadron Collider (HL-LHC) Experiments at CERN and other future HEP Experiments op- erating in severe radiation environments. This paper gives an overview of the RD50 collaboration activities and describes some examples of recent developments. Emphasis is put on the charac- terization of microscopic radiation induced defects and their impact on the sensor performance, the evaluation and parametrization of electric fields inside irradiated sensors, progress in device modeling using TCAD tools, the use of p-type silicon as strip and pixel sensor material and finally the first steps towards the exploitation of impact ionization ( charge...

  16. 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.

  17. 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

  18. 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

  19. Effects of radiation and temperature on gallium nitride (GaN) metal-semiconductor-metal ultraviolet photodetectors

    Science.gov (United States)

    Chiamori, Heather C.; Angadi, Chetan; Suria, Ateeq; Shankar, Ashwin; Hou, Minmin; Bhattacharya, Sharmila; Senesky, Debbie G.

    2014-06-01

    The development of radiation-hardened, temperature-tolerant materials, sensors and electronics will enable lightweight space sub-systems (reduced packaging requirements) with increased operation lifetimes in extreme harsh environments such as those encountered during space exploration. Gallium nitride (GaN) is a ceramic, semiconductor material stable within high-radiation, high-temperature and chemically corrosive environments due to its wide bandgap (3.4 eV). These material properties can be leveraged for ultraviolet (UV) wavelength photodetection. In this paper, current results of GaN metal-semiconductor-metal (MSM) UV photodetectors behavior after irradiation up to 50 krad and temperatures of 15°C to 150°C is presented. These initial results indicate that GaN-based sensors can provide robust operation within extreme harsh environments. Future directions for GaN-based photodetector technology for down-hole, automotive and space exploration applications are also discussed.

  20. 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)

  1. 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 ...

  2. 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)

  3. Ultrasensitive NO2 Sensor Based on Ohmic Metal-Semiconductor Interfaces of Electrolytically Exfoliated Graphene/Flame-Spray-Made SnO2 Nanoparticles Composite Operating at Low Temperatures.

    Science.gov (United States)

    Tammanoon, Nantikan; Wisitsoraat, Anurat; Sriprachuabwong, Chakrit; Phokharatkul, Ditsayut; Tuantranont, Adisorn; Phanichphant, Sukon; Liewhiran, Chaikarn

    2015-11-04

    In this work, flame-spray-made undoped SnO2 nanoparticles were loaded with 0.1-5 wt % electrolytically exfoliated graphene and systematically studied for NO2 sensing at low working temperatures. Characterizations by X-ray diffraction, transmission/scanning electron microscopy, and Raman and X-ray photoelectron spectroscopy indicated that high-quality multilayer graphene sheets with low oxygen content were widely distributed within spheriodal nanoparticles having polycrystalline tetragonal SnO2 phase. The 10-20 μm thick sensing films fabricated by spin coating on Au/Al2O3 substrates were tested toward NO2 at operating temperatures ranging from 25 to 350 °C in dry air. Gas-sensing results showed that the optimal graphene loading level of 0.5 wt % provided an ultrahigh response of 26,342 toward 5 ppm of NO2 with a short response time of 13 s and good recovery stabilization at a low optimal operating temperature of 150 °C. In addition, the optimal sensor also displayed high sensor response and relatively short response time of 171 and 7 min toward 5 ppm of NO2 at room temperature (25 °C). Furthermore, the sensors displayed very high NO2 selectivity against H2S, NH3, C2H5OH, H2, and H2O. Detailed mechanisms for the drastic NO2 response enhancement by graphene were proposed on the basis of the formation of graphene-undoped SnO2 ohmic metal-semiconductor junctions and accessible interfaces of graphene-SnO2 nanoparticles. Therefore, the electrolytically exfoliated graphene-loaded FSP-made SnO2 sensor is a highly promising candidate for fast, sensitive, and selective detection of NO2 at low operating temperatures.

  4. 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...

  5. 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)

  6. Manipulating semiconductor colloidal stability through doping.

    Science.gov (United States)

    Fleharty, Mark E; van Swol, Frank; Petsev, Dimiter N

    2014-10-10

    The interface between a doped semiconductor material and electrolyte solution is of considerable fundamental interest, and is relevant to systems of practical importance. Both adjacent domains contain mobile charges, which respond to potential variations. This is exploited to design electronic and optoelectronic sensors, and other enabling semiconductor colloidal materials. We show that the charge mobility in both phases leads to a new type of interaction between semiconductor colloids suspended in aqueous electrolyte solutions. This interaction is due to the electrostatic response of the semiconductor interior to disturbances in the external field upon the approach of two particles. The electrostatic repulsion between two charged colloids is reduced from the one governed by the charged groups present at the particles surfaces. This type of interaction is unique to semiconductor particles and may have a substantial effect on the suspension dynamics and stability.

  7. 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.)

  8. 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...

  9. 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

  10. 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.

  11. High dielectric constant PrYxOy sensing films electrolyte-insulator-semiconductor pH-sensor for the detection of urea

    International Nuclear Information System (INIS)

    Wu, Min-Hsien; Lee, Cheng-Da; Pan, Tung-Ming

    2009-01-01

    In this paper, we describe the structural and sensing properties of high-k PrY x O y sensing films deposited on Si substrates through reactive co-sputtering. Secondary ion mass spectrometry and atomic force microscopy were employed to analyze the compositional and morphological features of these films after annealing at various temperatures. The electrolyte-insulator-semiconductor (EIS) device incorporating a PrY x O y sensing membrane that had been annealed at 800 o C exhibited good sensing characteristics, including a high sensitivity (59.07 mV pH -1 in solutions from pH 2 to 12), a low hysteresis voltage (2.4 mV in the pH loop 7 → 4 → 7 → 10 → 7), and a small drift rate (0.62 mV h -1 in the buffer solution at pH 7). The PrY x O y EIS device also showed a high selective response towards H + . This improvement can be attributed to the small number of crystal defects and the large surface roughness. In addition, the enzymatic EIS-based urea biosensor incorporating a high-k PrY x O y sensing film annealed at 800 o C allowed the potentiometric analysis of urea, at concentrations ranging from 1 to 16 mM, with a sensitivity of 9.59 mV mM -1 .

  12. Qualification method for a 1 MGy-tolerant front-end chip designed in 65 nm CMOS for the read-out of remotely operated sensors and actuators during maintenance in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Verbeeck, Jens, E-mail: jens.verbeeck@esat.kuleuven.be [KU Leuven (KUL), Div. LRD-MAGyICS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); Cao, Ying [KU Leuven (KUL), Div. LRD-MAGyICS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); Van Uffelen, Marco; Casellas, Laura Mont; Damiani, Carlo; Morales, Emilio Ruiz; Santana, Roberto Ranz [Fusion for Energy (F4E), c/Josep, no. 2, Torres Diagonal Litoral, Ed. B3, 08019 Barcelona (Spain); Meek, Richard; Haist, Bernhard [Oxford Technologies Ltd. (OTL), 7 Nuffield Way, Abingdon OX14 1RL (United Kingdom); Hamilton, David [ITER Organisation (IO), Route de Vinon-sur-Verdon, CS 90 046, 13067 St. Paul les Durance Cedex (France); Steyaert, Michiel [KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); Leroux, Paul [KU Leuven, ESAT-MICAS, Kasteelpark Arenberg 10, 3001 Heverlee (Belgium); KU Leuven, ESAT, Advanced Integrated Sensing Lab (AdvISe), Kleinhoefstraat 4, 2440 Geel (Belgium)

    2015-10-15

    This paper describes the radiation qualification procedure for a 1 MGy-tolerant Application Specific Integrated Circuit (ASIC) developed in 65 nm CMOS technology. The chip is intended for the read-out of electrical signals of sensors and actuators during maintenance in ITER. First the general working principle of the ASIC is shown. The developed IC allows to read-out, condition and digitize multiple low bandwidth (<10 kHz) sensors. In addition the IC is able to multiplex the digitized sensor signals. To comply with ITER-relevant constraints an adapted radiation qualification procedure has been proposed. The radiation-qualification procedure describes the test criteria and test conditions of the developed ASICs, which are also compared with COTS alternatives, to meet the stringent qualification procedures for electronics exposed to radiation in ITER.

  13. Model supported sensor information platform for the transversal dynamics and longitudinal dynamics of vehicles. Applications to error diagnostics and error tolerance; Modellgestuetzte Sensorinformationsplattform fuer die Quer- und Laengsdynamik von Kraftfahrzeugen. Anwendungen zur Fehlerdiagnose und Fehlertoleranz

    Energy Technology Data Exchange (ETDEWEB)

    Halbe, Iris

    2008-07-01

    The contribution under consideration contacts engineers and scientists within the range of the motor vehicle dynamics. For the monitoring of the signals measured in series vehicle, a sensor information platform is designed. Thus, this supplies correct sensor information to the monitoring systems and offers estimated parameters and conditions for the regulation. The basis is a comprehensive concept of the transverse dynamics, longitudinal dynamics and staggering dynamics with different physical and experimental models. On the basis of these models, several procedures of error recognition are pointed out (observer, parity equations, parameter estimation), and their suitability in the driving dynamics is examined. Based on the results of error recognition, the defective sensor is diagnosed with Fuzzy in order to replace it with a computed signal. This error tolerance becomes possible by a two-trace model with a Kalman filter. Furthermore, conditions and parameters are estimated with different methods.

  14. 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)

  15. 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.

  16. Low-noise Magnetic Sensors

    KAUST Repository

    Kosel, Jü rgen; Sun, Jian

    2014-01-01

    Magnetic sensors are disclosed, as well as methods for fabricating and using the same. In some embodiments, an EMR effect sensor includes a semiconductor layer. In some embodiments, the EMR effect sensor may include a conductive layer substantially coupled to the semiconductor layer. In some embodiments, the EMR effect sensor may include a voltage lead coupled to the conductive layer. In some embodiments, the voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. In some embodiments, the EMR effect sensor may include a second voltage lead coupled to the semiconductor layer. In some embodiments, the second voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. Embodiments of a Hall effect sensor having the same or similar structure are also disclosed.

  17. Low-noise Magnetic Sensors

    KAUST Repository

    Kosel, Jurgen

    2014-03-27

    Magnetic sensors are disclosed, as well as methods for fabricating and using the same. In some embodiments, an EMR effect sensor includes a semiconductor layer. In some embodiments, the EMR effect sensor may include a conductive layer substantially coupled to the semiconductor layer. In some embodiments, the EMR effect sensor may include a voltage lead coupled to the conductive layer. In some embodiments, the voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. In some embodiments, the EMR effect sensor may include a second voltage lead coupled to the semiconductor layer. In some embodiments, the second voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. Embodiments of a Hall effect sensor having the same or similar structure are also disclosed.

  18. Fault Tolerant Control Systems

    DEFF Research Database (Denmark)

    Bøgh, S. A.

    This thesis considered the development of fault tolerant control systems. The focus was on the category of automated processes that do not necessarily comprise a high number of identical sensors and actuators to maintain safe operation, but still have a potential for improving immunity to component...

  19. Recent advancements in the development of radiation hard semiconductor detectors for S-LHC

    CERN Document Server

    Fretwurst, E; Al-Ajili, A A; Alfieri, G; Allport, P P; Artuso, M; Assouak, S; Avset, B S; Barabash, L; Barcz, A; Bates, R; Biagi, S F; Bilei, G M; Bisello, D; Blue, A; Blumenau, A; Boisvert, V; Bölla, G; Bondarenko, G B; Borchi, E; Borrello, L; Bortoletto, D; Boscardin, M; Bosisio, L; Bowcock, T J V; Brodbeck, T J; Broz, J; Bruzzi, M; Brzozowski, A; Buda, M; Buhmann, P; Buttar, C; Campabadal, F; Campbell, D; Candelori, A; Casse, G; Cavallini, A; Charron, S; Chilingarov, A G; Chren, D; Cindro, V; Collins, P; Coluccia, R; Contarato, D; Coutinho, J; Creanza, D; Cunningham, L; Dalla Betta, G F; Dawson, I; de Boer, Wim; De Palma, M; Demina, R; Dervan, P; Dittongo, S; Dolezal, Z; Dolgolenko, A; Eberlein, T; Eremin, V; Fall, C; Fasolo, F; Ferbel, T; Fizzotti, F; Fleta, C; Focardi, E; Forton, E; García, C; García-Navarro, J E; Gaubas, E; Genest, M H; Gill, K A; Giolo, K; Glaser, M; Gössling, C; Golovine, V; González-Sevilla, S; Gorelov,I; Goss, J; Gouldwell-Bates, A; Grégoire, G; Gregori, P; Grigoriev, E; Grillo, A A; Groza, A; Guskov, J; Haddad, L; Härkönen, J; Hauler, F; Hoeferkamp, M; Honniger, F; Horazdovsky, T; Horisberger, R P; Horn, M; Houdayer, A; Hourahine, B; Hughes, G; Ilyashenko, Yu S; Irmscher, K; Ivanov, A; Jarasiunas, K; Johansen, K M H; Jones, B K; Jones, R; Joram, C; Jungermann, L; Kalinina, E; Kaminski, P; Karpenko, A; Karpov, A; Kazlauskiene, V; Kazukauskas, V; Khivrich, V; Khomenkov, V P; Kierstead, J A; Klaiber Lodewigs, J M; Klingenberg, R; Kodys, P; Kohout, Z; Korjenevski, S; Koski, M; Kozlowski, R; Kozodaev, M; Kramberger, G; Krasel, O; Kuznetsov, A; Kwan, S; Lagomarsino, S; Lassila-Perini, K M; Lastovetsky, V F; Latino, G; Lazanu, I; Lazanu, S; Lebedev, A; Lebel, C; Leinonen, K; Leroy, C; Li, Z; Lindström, G; Linhart, V; Litovchenko, P G; Litovchenko, A P; Lo Giudice, A; Lozano, M; Luczynski, Z; Luukka, Panja; Macchiolo, A; Makarenko, L F; Mandic, I; Manfredotti, C; Manna, N; Martí i García, S; Marunko, S; Mathieson, K; Melone, J; Menichelli, D; Messineo, A; Metcalfe, J; Miglio, S; Mikuz, M; Miyamoto, J; Moll, M; Monakhov, E; Moscatelli, F; Naoumov, D; Nossarzhevska, E; Nysten, J; Olivero, P; O'Shea, V; Palviainen, T; Paolini, C; Parkes, C; Passeri, D; Pein, U; Pellegrini, G; Perera, L; Petasecca, M; Piemonte, C; Pignatel, G U; Pinho, N; Pintilie, I; Pintilie, L; Polivtsev, L; Polozov, P; Popa, A; Populea, J; Pospísil, S; Pozza, A; Radicci, V; Rafí, J M; Rando, R; Röder, R; Rohe, T; Ronchin, S; Rott, C; Roy, A; Ruzin, A; Sadrozinski, H F W; Sakalauskas, S; Scaringella, M; Schiavulli, L; Schnetzer, S; Schumm, B; Sciortino, S; Scorzoni, A; Segneri, G; Seidela, S; Seiden, A; Sellberg, G; Sellin, P J; Sentenac, D; Shipsey, I; Sícho, P; Sloan, T; Solar, M; Son, S; Sopko, B; Sopko, V; Spencer, N; Stahl, J; Stolze, D; Stone, R; Storasta, J; Strokan, N; Sudzius, M; Surma, B; Suvorov, A; Svensson, B G; Tipton, P; Tomasek, M; Tsvetkov, A; Tuominen, E; Tuovinen, E; Tuuva, T; Tylchin, M; Uebersee, H; Uher, J; Ullán, M; Vaitkus, J V; Velthuis, J; Verbitskaya, E; Vrba, V; Wagner, G; Wilhelm, I; Worm, S; Wright, V; Wunstorf, R; Yiuri, Y; Zabierowski, P; Zaluzhny, A; Zavrtanik, M; Zen, M; Zhukov, V; Zorzi, N

    2005-01-01

    The proposed luminosity upgrade of the Large Hadron Collider (S-LHC) at CERN will demand the innermost layers of the vertex detectors to sustain fluences of about 1016 hadrons/cm2. Due to the high multiplicity of tracks, the required spatial resolution and the extremely harsh radiation field new detector concepts and semiconductor materials have to be explored for a possible solution of this challenge. The CERN RD50 collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” has started in 2002 an R&D program for the development of detector technologies that will fulfill the requirements of the S-LHC. Different strategies are followed by RD50 to improve the radiation tolerance. These include the development of defect engineered silicon like Czochralski, epitaxial and oxygen-enriched silicon and of other semiconductor materials like SiC and GaN as well as extensive studies of the microscopic defects responsible for the degradation of irradiated sensors. Furthe...

  20. 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

  1. Silicon sensors for trackers at high-luminosity environment

    Energy Technology Data Exchange (ETDEWEB)

    Peltola, Timo, E-mail: timo.peltola@helsinki.fi

    2015-10-01

    The planned upgrade of the LHC accelerator at CERN, namely the high luminosity (HL) phase of the LHC (HL-LHC foreseen for 2023), will result in a more intense radiation environment than the present tracking system that was designed for. The required upgrade of the all-silicon central trackers at the ALICE, ATLAS, CMS and LHCb experiments will include higher granularity and radiation hard sensors. The radiation hardness of the new sensors must be roughly an order of magnitude higher than in the current LHC detectors. To address this, a massive R&D program is underway within the CERN RD50 Collaboration “Development of Radiation Hard Semiconductor Devices for Very High Luminosity Colliders” to develop silicon sensors with sufficient radiation tolerance. Research topics include the improvement of the intrinsic radiation tolerance of the sensor material and novel detector designs with benefits like reduced trapping probability (thinned and 3D sensors), maximized sensitive area (active edge sensors) and enhanced charge carrier generation (sensors with intrinsic gain). A review of the recent results from both measurements and TCAD simulations of several detector technologies and silicon materials at radiation levels expected for HL-LHC will be presented. - Highlights: • An overview of the recent results from the RD50 collaboration. • Accuracy of TCAD simulations increased by including both bulk and surface damage. • Sensors with n-electrode readout and MCz material offer higher radiation hardness. • 3D detectors are a promising choice for the extremely high fluence environments. • Detectors with an enhanced charge carrier generation under systematic investigation.

  2. Chemoresistive gas sensor

    Science.gov (United States)

    Hirschfeld, T.B.

    1987-06-23

    A chemoresistive gas sensor is provided which has improved sensitivity. A layer of organic semiconductor is disposed between two electrodes which, in turn, are connected to a voltage source. High conductivity material is dispersed within the layer of organic semiconductor in the form of very small particles, or islands. The average interisland spacing is selected so that the predominant mode of current flow is by way of electron funneling. Adsorption of gaseous contaminant onto the layer of organic semiconductor modulates the tunneling current in a quantitative manner. 2 figs.

  3. 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

  4. 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

  5. Commercialization of radiation tolerant camera

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Bum; Choi, Young Soo; Kim, Sun Ku; Lee, Jong Min; Cha, Bung Hun; Lee, Nam Ho; Byun, Eiy Gyo; Yoo, Seun Wook; Choi, Bum Ki; Yoon, Sung Up; Kim, Hyun Gun; Sin, Jeong Hun; So, Suk Il

    1999-12-01

    In this project, radiation tolerant camera which tolerates 10{sup 6} - 10{sup 8} rad total dose is developed. In order to develop radiation tolerant camera, radiation effect of camera components was examined and evaluated, and camera configuration was studied. By the result of evaluation, the components were decided and design was performed. Vidicon tube was selected to use by image sensor and non-browning optics and camera driving circuit were applied. The controller needed for CCTV camera system, lens, light, pan/tilt controller, was designed by the concept of remote control. And two type of radiation tolerant camera were fabricated consider to use in underwater environment or normal environment. (author)

  6. Commercialization of radiation tolerant camera

    International Nuclear Information System (INIS)

    Lee, Yong Bum; Choi, Young Soo; Kim, Sun Ku; Lee, Jong Min; Cha, Bung Hun; Lee, Nam Ho; Byun, Eiy Gyo; Yoo, Seun Wook; Choi, Bum Ki; Yoon, Sung Up; Kim, Hyun Gun; Sin, Jeong Hun; So, Suk Il

    1999-12-01

    In this project, radiation tolerant camera which tolerates 10 6 - 10 8 rad total dose is developed. In order to develop radiation tolerant camera, radiation effect of camera components was examined and evaluated, and camera configuration was studied. By the result of evaluation, the components were decided and design was performed. Vidicon tube was selected to use by image sensor and non-browning optics and camera driving circuit were applied. The controller needed for CCTV camera system, lens, light, pan/tilt controller, was designed by the concept of remote control. And two type of radiation tolerant camera were fabricated consider to use in underwater environment or normal environment. (author)

  7. Electro-chemical sensors, sensor arrays and circuits

    Science.gov (United States)

    Katz, Howard E.; Kong, Hoyoul

    2014-07-08

    An electro-chemical sensor includes a first electrode, a second electrode spaced apart from the first electrode, and a semiconductor channel in electrical contact with the first and second electrodes. The semiconductor channel includes a trapping material. The trapping material reduces an ability of the semiconductor channel to conduct a current of charge carriers by trapping at least some of the charge carriers to localized regions within the semiconductor channel. The semiconductor channel includes at least a portion configured to be exposed to an analyte to be detected, and the trapping material, when exposed to the analyte, interacts with the analyte so as to at least partially restore the ability of the semiconductor channel to conduct the current of charge carriers.

  8. Charged Semiconductor Defects Structure, Thermodynamics and Diffusion

    CERN Document Server

    Seebauer, Edmund G

    2009-01-01

    The technologically useful properties of a solid often depend upon the types and concentrations of the defects it contains. Not surprisingly, defects in semiconductors have been studied for many years, in many cases with a view towards controlling their behavior through various forms of "defect engineering." For example, in the bulk, charging significantly affects the total concentration of defects that are available to mediate phenomena such as solid-state diffusion. Surface defects play an important role in mediating surface mass transport during high temperature processing steps such as epitaxial film deposition, diffusional smoothing in reflow, and nanostructure formation in memory device fabrication. Charged Semiconductor Defects details the current state of knowledge regarding the properties of the ionized defects that can affect the behavior of advanced transistors, photo-active devices, catalysts, and sensors. Features: Group IV, III-V, and oxide semiconductors; Intrinsic and extrinsic defects; and, P...

  9. 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...

  10. 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.)

  11. 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...

  12. Hybrid organic semiconductor lasers for bio-molecular sensing.

    Science.gov (United States)

    Haughey, Anne-Marie; Foucher, Caroline; Guilhabert, Benoit; Kanibolotsky, Alexander L; Skabara, Peter J; Burley, Glenn; Dawson, Martin D; Laurand, Nicolas

    2014-01-01

    Bio-functionalised luminescent organic semiconductors are attractive for biophotonics because they can act as efficient laser materials while simultaneously interacting with molecules. In this paper, we present and discuss a laser biosensor platform that utilises a gain layer made of such an organic semiconductor material. The simple structure of the sensor and its operation principle are described. Nanolayer detection is shown experimentally and analysed theoretically in order to assess the potential and the limits of the biosensor. The advantage conferred by the organic semiconductor is explained, and comparisons to laser sensors using alternative dye-doped materials are made. Specific biomolecular sensing is demonstrated, and routes to functionalisation with nucleic acid probes, and future developments opened up by this achievement, are highlighted. Finally, attractive formats for sensing applications are mentioned, as well as colloidal quantum dots, which in the future could be used in conjunction with organic semiconductors.

  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. 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...

  17. 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...

  18. 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.

  19. Radiation tolerance of Si{sub 1−y}C{sub y} source/drain n-type metal oxide semiconductor field effect transistors with different carbon concentrations

    Energy Technology Data Exchange (ETDEWEB)

    Nakashima, Toshiyuki, E-mail: nakashima_t@cdk.co.jp [Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki (Japan); Chuo Denshi Kogyo Co., Ltd., 3400 Kohoyama, Matsubase, Uki, Kumamoto (Japan); Asai, Yuki; Hori, Masato; Yoneoka, Masashi; Tsunoda, Isao; Takakura, Kenichiro [Kumamoto National College of Technology, 2659-2 Suya, Koshi, Kumamoto 861-1102 (Japan); Gonzalez, Mireia Bargallo [Institut de Microelectronica de Barcelona (Centre Nacional de Microelectronica — Consejo Superior de Investigaciones Cientificas) Campus UAB, 08193 Bellaterra (Spain); Simoen, Eddy [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Claeys, Cor [imec, Kapeldreef 75, B-3001 Leuven (Belgium); Department of Electrical Engineering, KU Leuven, Kasteelpark Arenberg 10, B-3001 Leuven (Belgium); Yoshino, Kenji [Interdisciplinary Graduate School of Agriculture and Engineering, University of Miyazaki, 1-1 Gakuen Kibanadai-nishi, Miyazaki (Japan)

    2014-04-30

    The 2-MeV electron radiation damage of silicon–carbon source/drain (S/D) n-type metal oxide semiconductor field effect transistors with different carbon (C) concentrations is studied. Before irradiation, an enhancement of the electron mobility with C concentration of the S/D stressors is clearly observed. On the other hand, after electron irradiation, both the threshold voltage shift and the maximum electron mobility degradation are independent on the C concentration for all electron fluences studied. These results indicate that the strain induced electron mobility enhancement due to the C doping is retained after irradiation in the studied devices. - Highlights: • We have investigated the electron irradiation effect of the Si{sub 1−y}C{sub y} S/D n-MOSFETs. • The threshold voltage variations by irradiation are independent on the C doping. • The electron-mobility decreased for all C concentrations by electron irradiation. • The strain induced mobility enhancement effect is retained after irradiation.

  20. CMOS Active-Pixel Image Sensor With Simple Floating Gates

    Science.gov (United States)

    Fossum, Eric R.; Nakamura, Junichi; Kemeny, Sabrina E.

    1996-01-01

    Experimental complementary metal-oxide/semiconductor (CMOS) active-pixel image sensor integrated circuit features simple floating-gate structure, with metal-oxide/semiconductor field-effect transistor (MOSFET) as active circuit element in each pixel. Provides flexibility of readout modes, no kTC noise, and relatively simple structure suitable for high-density arrays. Features desirable for "smart sensor" applications.

  1. Charge collection and non-ionizing radiation tolerance of CMOS pixel sensors using a 0.18 μm CMOS process

    Science.gov (United States)

    Zhang, Ying; Zhu, Hongbo; Zhang, Liang; Fu, Min

    2016-09-01

    The proposed Circular Electron Positron Collider (CEPC) will be primarily aimed for precision measurements of the discovered Higgs boson. Its innermost vertex detector, which will play a critical role in heavy-flavor tagging, must be constructed with fine-pitched silicon pixel sensors with low power consumption and fast readout. CMOS pixel sensor (CPS), as one of the most promising candidate technologies, has already demonstrated its excellent performance in several high energy physics experiments. Therefore it has been considered for R&D for the CEPC vertex detector. In this paper, we present the preliminary studies to improve the collected signal charge over the equivalent input capacitance ratio (Q / C), which will be crucial to reduce the analog power consumption. We have performed detailed 3D device simulation and evaluated potential impacts from diode geometry, epitaxial layer properties and non-ionizing radiation damage. We have proposed a new approach to improve the treatment of the boundary conditions in simulation. Along with the TCAD simulation, we have designed the exploratory prototype utilizing the TowerJazz 0.18 μm CMOS imaging sensor process and we will verify the simulation results with future measurements.

  2. Embedded sensor systems

    CERN Document Server

    Agrawal, Dharma Prakash

    2017-01-01

    This inspiring textbook provides an introduction to wireless technologies for sensors, explores potential use of sensors for numerous applications, and utilizes probability theory and mathematical methods as a means of embedding sensors in system design. It discusses the need for synchronization and underlying limitations, inter-relation between given coverage and connectivity to number of sensors needed, and the use of geometrical distance to determine location of the base station for data collection and explore use of anchor nodes for relative position determination of sensors. The book explores energy conservation, communication using TCP, the need for clustering and data aggregation, and residual energy determination and energy harvesting. It covers key topics of sensor communication like mobile base stations and relay nodes, delay-tolerant sensor networks, and remote sensing and possible applications. The book defines routing methods and do performance evaluation for random and regular sensor topology an...

  3. CMOS Integrated Carbon Nanotube Sensor

    International Nuclear Information System (INIS)

    Perez, M. S.; Lerner, B.; Boselli, A.; Lamagna, A.; Obregon, P. D. Pareja; Julian, P. M.; Mandolesi, P. S.; Buffa, F. A.

    2009-01-01

    Recently carbon nanotubes (CNTs) have been gaining their importance as sensors for gases, temperature and chemicals. Advances in fabrication processes simplify the formation of CNT sensor on silicon substrate. We have integrated single wall carbon nanotubes (SWCNTs) with complementary metal oxide semiconductor process (CMOS) to produce a chip sensor system. The sensor prototype was designed and fabricated using a 0.30 um CMOS process. The main advantage is that the device has a voltage amplifier so the electrical measure can be taken and amplified inside the sensor. When the conductance of the SWCNTs varies in response to media changes, this is observed as a variation in the output tension accordingly.

  4. Crafting tolerance

    DEFF Research Database (Denmark)

    Kirchner, Antje; Freitag, Markus; Rapp, Carolin

    2011-01-01

    Ongoing changes in social structures, orientation, and value systems confront us with the growing necessity to address and understand transforming patterns of tolerance as well as specific aspects, such as social tolerance. Based on hierarchical analyses of the latest World Values Survey (2005......–08) and national statistics for 28 countries, we assess both individual and contextual aspects that influence an individual's perception of different social groupings. Using a social tolerance index that captures personal attitudes toward these groupings, we present an institutional theory of social tolerance. Our...

  5. 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

  6. 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.

  7. 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.

  8. 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

  9. 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.

  10. 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

  11. Defect Tolerance to Intolerance in the Vacancy-Ordered Double Perovskite Semiconductors Cs 2 SnI 6 and Cs 2 TeI 6

    Energy Technology Data Exchange (ETDEWEB)

    Maughan, Annalise E.; Ganose, Alex M.; Bordelon, Mitchell M.; Miller, Elisa M.; Scanlon, David O.; Neilson, James R.

    2016-07-13

    Vacancy-ordered double perovskites of the general formula, A2BX6, are a family of perovskite derivatives composed of a face-centered lattice of nearly isolated [BX6] units with A-site cations occupying the cuboctahedral voids. Despite the presence of isolated octahedral units, the close-packed iodide lattice provides significant electronic dispersion, such that Cs2SnI6 has recently been explored for applications in photovoltaic devices. To elucidate the structure-property relationships of these materials, we have synthesized the solid solution Cs2Sn1-xTexI6. However, even though tellurium substitution increases electronic dispersion via closer I-I contact distances, the substitution experimentally yields insulating behavior from a significant decrease in carrier concentration and mobility. Density functional calculations of native defects in Cs2SnI6 reveal that iodine vacancies exhibit a low enthalpy of formation and the defect energy level is a shallow donor to the conduction band, rendering the material tolerant to these defect states. The increased covalency of Te-I bonding renders the formation of iodine vacancy states unfavorable, and is responsible for the reduction in conductivity upon Te substitution. Additionally, Cs2TeI6 is intolerant to the formation of these defects, as the defect level occurs deep within the band gap and thus localizes potential mobile charge carriers. In these vacancy-ordered double perovskites, the close-packed lattice of iodine provides significant electronic dispersion, while the interaction of the B- and X-site ions dictates the properties as they pertain to electronic structure and defect tolerance. This simplified perspective -- based on extensive experimental and theoretical analysis -- provides a platform from which to understand structure-property relationships in functional perovskite halides.

  12. EDITORIAL The 23rd Nordic Semiconductor Meeting The 23rd Nordic Semiconductor Meeting

    Science.gov (United States)

    Ólafsson, Sveinn; Sveinbjörnsson, Einar

    2010-12-01

    A Nordic Semiconductor Meeting is held every other year with the venue rotating amongst the Nordic countries of Denmark, Finland, Iceland, Norway and Sweden. The focus of these meetings remains 'original research and science being carried out on semiconductor materials, devices and systems'. Reports on industrial activity have usually featured. The topics have ranged from fundamental research on point defects in a semiconductor to system architecture of semiconductor electronic devices. Proceedings from these events are regularly published as a topical issue of Physica Scripta. All of the papers in this topical issue have undergone critical peer review and we wish to thank the reviewers and the authors for their cooperation, which has been instrumental in meeting the high scientific standards and quality of the series. This meeting of the 23rd Nordic Semiconductor community, NSM 2009, was held at Háskólatorg at the campus of the University of Iceland, Reykjavik, Iceland, 14-17 June 2009. Support was provided by the University of Iceland. Almost 50 participants presented a broad range of topics covering semiconductor materials and devices as well as related material science interests. The conference provided a forum for Nordic and international scientists to present and discuss new results and ideas concerning the fundamentals and applications of semiconductor materials. The meeting aim was to advance the progress of Nordic science and thus aid in future worldwide technological advances concerning technology, education, energy and the environment. Topics Theory and fundamental physics of semiconductors Emerging semiconductor technologies (for example III-V integration on Si, novel Si devices, graphene) Energy and semiconductors Optical phenomena and optical devices MEMS and sensors Program 14 June Registration 13:00-17:00 15 June Meeting program 09:30-17:00 and Poster Session I 16 June Meeting program 09:30-17:00 and Poster Session II 17 June Excursion and dinner

  13. Differential multi-MOSFET nuclear radiation sensor

    Science.gov (United States)

    Deoliveira, W. A.

    1977-01-01

    Circuit allows minimization of thermal-drift errors, low power consumption, operation over wide dynamic range, improved sensitivity and stability with metaloxide-semiconductor field-effect transistor sensors.

  14. Microelectronic temperature sensor; silicon temperature sensor

    International Nuclear Information System (INIS)

    Beitner, M.; Kanert, W.; Reichert, H.

    1982-01-01

    The goal of this work was to develop a silicon temperature sensor with a sensitivity and a reliability as high and a tolerance as small as possible, for use in measurement and control. By employing the principle of spreading-resistance, using silicon doped by neutron transmutation, and trimming of the single wafer tolerances of resistance less than +- 5% can be obtained; overstress tests yielded a long-term stability better than 0.2%. Some applications show the advantageous use of this sensor. (orig.) [de

  15. Real-Time Fault Tolerant Networking Protocols

    National Research Council Canada - National Science Library

    Henzinger, Thomas A

    2004-01-01

    We made significant progress in the areas of video streaming, wireless protocols, mobile ad-hoc and sensor networks, peer-to-peer systems, fault tolerant algorithms, dependability and timing analysis...

  16. 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.

  17. 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.

  18. Photoacoustic Techniques for Trace Gas Sensing Based on Semiconductor Laser Sources

    Directory of Open Access Journals (Sweden)

    Vincenzo Spagnolo

    2009-12-01

    Full Text Available The paper provides an overview on the use of photoacoustic sensors based on semiconductor laser sources for the detection of trace gases. We review the results obtained using standard, differential and quartz enhanced photoacoustic techniques.

  19. 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

  20. 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

  1. Where science fiction meets reality? With oxide semiconductors.

    Energy Technology Data Exchange (ETDEWEB)

    Fortunato, E.; Martins, R. [CENIMAT/I3N, Departamento de Ciencia dos Materiais, Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, CEMOP-UNINOVA, 2829-516 Caparica (Portugal)

    2011-09-15

    Transparent electronics is today one of the most advanced topics for a wide range of device applications, where the key components are wide band gap semiconductors, where oxides of different origin play an important role, not only as passive components but also as active components similar to what we observe in conventional semiconductors. As passive components they include the use of these materials as dielectrics for a wide range of electronic devices and also as transparent electrical conductors for use in several optoelectronic applications, such as liquid crystal displays, organic light emitting diodes, solar cells, optical sensors etc. As active materials, they exploit the use of truly electronic semiconductors where the main emphasis is being put on transparent thin film transistors, light emitting diodes, lasers, ultraviolet sensors and integrated circuits among others. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. Liquid Crystalline Semiconductors Materials, properties and applications

    CERN Document Server

    Kelly, Stephen; O'Neill, Mary

    2013-01-01

    This is an exciting stage in the development of organic electronics. It is no longer an area of purely academic interest as increasingly real applications are being developed, some of which are beginning to come on-stream. Areas that have already been commercially developed or which are under intensive development include organic light emitting diodes (for flat panel displays and solid state lighting), organic photovoltaic cells, organic thin film transistors (for smart tags and flat panel displays) and sensors. Within the family of organic electronic materials, liquid crystals are relative newcomers. The first electronically conducting liquid crystals were reported in 1988 but already a substantial literature has developed. The advantage of liquid crystalline semiconductors is that they have the easy processability of amorphous and polymeric semiconductors but they usually have higher charge carrier mobilities. Their mobilities do not reach the levels seen in crystalline organics but they circumvent all of t...

  3. Om tolerance

    DEFF Research Database (Denmark)

    Huggler, Jørgen

    2007-01-01

    Begrebet tolerance og dets betydninger diskuteres med henblik på en tydeliggørelse af begrebets forbindelse med stat, religion, ytringsfrihed, skeptisk erkendelsesteori, antropologi og pædagogik.......Begrebet tolerance og dets betydninger diskuteres med henblik på en tydeliggørelse af begrebets forbindelse med stat, religion, ytringsfrihed, skeptisk erkendelsesteori, antropologi og pædagogik....

  4. Modeling of semiconductor nanostructures and semiconductor-electrolyte interfaces

    International Nuclear Information System (INIS)

    Birner, Stefan

    2011-01-01

    The main objective of Part I is to give an overview of some of the methods that have been implemented into the nextnano 3 software. Examples are discussed that give insight into doping, strain and mobility. Applications of the single-band Schroedinger equation include three-dimensional superlattices, and a qubit that is manipulated by a magnetic field. Results of the multi-band k.p method are presented for HgTe-CdTe and InAs-GaSb superlattices, and for a SiGe-Si quantum cascade structure. Particular focus is put on a detailed description of the contact block reduction (CBR) method that has been developed within our research group. By means of this approach, quantum transport in the ballistic limit in one, two and three dimensions can be calculated. I provide a very detailed description of the algorithm and present several well documented examples that highlight the key points of this method. Calculating quantum transport in three dimensions is a very challenging task where computationally efficient algorithms - apart from the CBR method - are not available yet. Part II describes the methods that I have implemented into the nextnano 3 software for calculating systems that consist of a combination of semiconductor materials and liquids. These biosensors have a solid-electrolyte interface, and the charges in the solid and in the electrolyte are coupled to each other through the Poisson-Boltzmann equation. I apply this model to a silicon based protein sensor, where I solve the Schroedinger equation together with the Poisson-Boltzmann equation self-consistently, and compare theoretical results with experiment. Furthermore, I have developed a novel approach to model the charge density profiles at semiconductor-electrolyte interfaces that allows us to distinguish hydrophobic and hydrophilic interfaces. Our approach extends previous work where ion specific potentials of mean force describe the distribution of ion species at the interface. I apply this new model to recently

  5. Modeling of semiconductor nanostructures and semiconductor-electrolyte interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Birner, Stefan

    2011-11-15

    The main objective of Part I is to give an overview of some of the methods that have been implemented into the nextnano{sup 3} software. Examples are discussed that give insight into doping, strain and mobility. Applications of the single-band Schroedinger equation include three-dimensional superlattices, and a qubit that is manipulated by a magnetic field. Results of the multi-band k.p method are presented for HgTe-CdTe and InAs-GaSb superlattices, and for a SiGe-Si quantum cascade structure. Particular focus is put on a detailed description of the contact block reduction (CBR) method that has been developed within our research group. By means of this approach, quantum transport in the ballistic limit in one, two and three dimensions can be calculated. I provide a very detailed description of the algorithm and present several well documented examples that highlight the key points of this method. Calculating quantum transport in three dimensions is a very challenging task where computationally efficient algorithms - apart from the CBR method - are not available yet. Part II describes the methods that I have implemented into the nextnano{sup 3} software for calculating systems that consist of a combination of semiconductor materials and liquids. These biosensors have a solid-electrolyte interface, and the charges in the solid and in the electrolyte are coupled to each other through the Poisson-Boltzmann equation. I apply this model to a silicon based protein sensor, where I solve the Schroedinger equation together with the Poisson-Boltzmann equation self-consistently, and compare theoretical results with experiment. Furthermore, I have developed a novel approach to model the charge density profiles at semiconductor-electrolyte interfaces that allows us to distinguish hydrophobic and hydrophilic interfaces. Our approach extends previous work where ion specific potentials of mean force describe the distribution of ion species at the interface. I apply this new model

  6. 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

  7. 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.

  8. 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...

  9. 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 ...

  10. 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...

  11. 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

  12. 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.

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. Performance of the ATLAS semiconductor tracker

    CERN Document Server

    Alpigiani, C; The ATLAS collaboration

    2014-01-01

    We report the operation and performance of the ATLAS Semi-Conductor Tracker (SCT) functioning in a high luminosity and high radiation environment. The SCT is part of the inner tracking system of the ATLAS experiment at CERN and is constructed of 4088 modules assembled from silicon-strip sensors for a total of 6.3 million channels more than 99 % of which were fully functional throughout all data taking periods. Noise occupancy and hit efficiency as well as the Lorentz angle and radiation damage measurements will be discussed in details.

  19. 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)

  20. 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

  1. 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

  2. Clementine sensor suite

    Energy Technology Data Exchange (ETDEWEB)

    Ledebuhr, A.G. [Lawrence Livermore National Lab., CA (United States)

    1994-11-15

    LLNL designed and built the suite of six miniaturized light-weight space-qualified sensors utilized in the Clementine mission. A major goal of the Clementine program was to demonstrate technologies originally developed for Ballistic Missile Defense Organization Programs. These sensors were modified to gather data from the moon. This overview presents each of these sensors and some preliminary on-orbit performance estimates. The basic subsystems of these sensors include optical baffles to reject off-axis stray light, light-weight ruggedized optical systems, filter wheel assemblies, radiation tolerant focal plane arrays, radiation hardened control and readout electronics and low mass and power mechanical cryogenic coolers for the infrared sensors. Descriptions of each sensor type are given along with design specifications, photographs and on-orbit data collected.

  3. Working Group Report: Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Artuso, M.; et al.,

    2013-10-18

    Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In addition the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.

  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. 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)

  7. 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

  8. Towards Tolerance

    NARCIS (Netherlands)

    Lisette Kuyper; Jurjen Iedema; Saskia Keuzenkamp

    2013-01-01

    Across Europe, public attitudes towards lesbian, gay and bisexual (LGB) individuals range from broad tolerance to widespread rejection. Attitudes towards homosexuality are more than mere individual opinions, but form part of the social and political structures which foster or hinder the equality

  9. Intolerant tolerance.

    Science.gov (United States)

    Khushf, G

    1994-04-01

    The Hyde Amendment and Roman Catholic attempts to put restrictions on Title X funding have been criticized for being intolerant. However, such criticism fails to appreciate that there are two competing notions of tolerance, one focusing on the limits of state force and accepting pluralism as unavoidable, and the other focusing on the limits of knowledge and advancing pluralism as a good. These two types of tolerance, illustrated in the writings of John Locke and J.S. Mill, each involve an intolerance. In a pluralistic context where the free exercise of religion is respected, John Locke's account of tolerance is preferable. However, it (in a reconstructed form) leads to a minimal state. Positive entitlements to benefits like artificial contraception or nontherapeutic abortions can legitimately be resisted, because an intolerance has already been shown with respect to those that consider the benefit immoral, since their resources have been coopted by taxation to advance an end that is contrary to their own. There is a sliding scale from tolerance (viewed as forbearance) to the affirmation of communal integrity, and this scale maps on to the continuum from negative to positive rights.

  10. Architectures for Improved Organic Semiconductor Devices

    Science.gov (United States)

    Beck, Jonathan H.

    Advancements in the microelectronics industry have brought increasing performance and decreasing prices to a wide range of users. Conventional silicon-based electronics have followed Moore's law to provide an ever-increasing integrated circuit transistor density, which drives processing power, solid-state memory density, and sensor technologies. As shrinking conventional integrated circuits became more challenging, researchers began exploring electronics with the potential to penetrate new applications with a low price of entry: "Electronics everywhere." The new generation of electronics is thin, light, flexible, and inexpensive. Organic electronics are part of the new generation of thin-film electronics, relying on the synthetic flexibility of carbon molecules to create organic semiconductors, absorbers, and emitters which perform useful tasks. Organic electronics can be fabricated with low energy input on a variety of novel substrates, including inexpensive plastic sheets. The potential ease of synthesis and fabrication of organic-based devices means that organic electronics can be made at very low cost. Successfully demonstrated organic semiconductor devices include photovoltaics, photodetectors, transistors, and light emitting diodes. Several challenges that face organic semiconductor devices are low performance relative to conventional devices, long-term device stability, and development of new organic-compatible processes and materials. While the absorption and emission performance of organic materials in photovoltaics and light emitting diodes is extraordinarily high for thin films, the charge conduction mobilities are generally low. Building highly efficient devices with low-mobility materials is one challenge. Many organic semiconductor films are unstable during fabrication, storage, and operation due to reactions with water, oxygen and hydroxide. A final challenge facing organic electronics is the need for new processes and materials for electrodes

  11. Faraday effect in semimagnetic semiconductors

    International Nuclear Information System (INIS)

    Nikitin, P.I.; Savchuk, A.I.

    1990-01-01

    Experimental and theoretical studies of the Faraday effect in a new class of materials -semimagnetic semiconductors (SS) have been received. Mechanisms of the giant Faraday effect in SS based on s, p-d exchange interaction of excitons, electrons and holes with magnetic ions have been discussed. Faraday rotation as a function of a radiation wavelength, magnetic component concentration, temperature, magnetic field intensity for crystals A 2 B 6 (Mn)A 2 x -1Mn xB 6 : and other SS (GaAs(Mn), CdP 2 (Mn),Pb 1-X2 )Mn x J 2 have been considered. We have attended to use FR for the study of a paramagnetic-spin glass transmission for determining the role of the relaxation effects with a participation of magnetic Mn 2+ ions, exitons, polarons in the direct and inverse Faraday effects. In addition the features of FR in thin films of SS and in spin superlattices have been discussed. Finally, we have analysed possibilities of applying the SS Faraday effect for developing magnetooptic devices (optical isolators and fibre optic sensors of magnetic fields)

  12. Fundamental investigation of hybrid high-temperature superconductor-semiconductor sensors for magnetic signals in non-destructive evaluation. Final report; Grundlegende Untersuchungen hybrider Hochtemperatursupraleiter-Halbleiter-Magnetfelddetektoren auf Siliziumsubstraten fuer Anwendungen in der zerstoerungsfreien Pruefung. Abschlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Seidel, P.; Schmidl, F.; Linzen, S.; Schmidt, F.; Scherbel, J.

    2002-11-01

    A new magnetic sensor was realized using a Hall magnetometer coupled to an antenna out of high-temperature superconducting material. The resolution of the magnetometer was improved and a noise-limited field resolution of the system of 2.7 nT/{radical}(Hz) was obtained. The necessary thin film technology was developed and optimized. Further improvements will result in 0.5 nT/{radical}(Hz). The sensors were realized as single sensors as well as sensor arrays and successfully tested in a system for non-destructive evaluation. Within this system the cooling was established by a cryocooler which also cools down the electronics to about 80 K. (orig.) [German] Es wurde ein neuartiger Magnetfeldsensor realisiert, bei dem ein Hallmagnetometer mit einer Antenne aus Hochtemperatursupraleitenden Material gekoppelt wird. Die Magnetometerempfindlichkeit wird dadurch kiar verbessert und eine rauschbegrenzte Feldaufloesung des Systems von 2,7 nT{radical}(/Hz) erreicht. Die zur Herstellung noetige hybride Duennschichttechnologie wurde entwickelt und optimiert. Durch Layoutverbesserungen erscheinen Aufloesungen von 0,5 nT/{radical}(Hz) realisierbar. Die Sensoren wurden als Einzelsensor und Sensorarrays realisiert und in einer Anlage zur zerstoerungsfreien Pruefung erfolgreich getestet. Dabei erfolgte die Kuehlung mittels Kleinkuehler, der auch die Verarbeitungselektronik auf 80 K kuehlt. (orig.)

  13. 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.

  14. 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)

  15. Basic semiconductor physics

    CERN Document Server

    Hamaguchi, Chihiro

    2017-01-01

    This book presents a detailed description of basic semiconductor physics. The text covers a wide range of important phenomena in semiconductors, from the simple to the advanced. Four different methods of energy band calculations in the full band region are explained: local empirical pseudopotential, non-local pseudopotential, KP perturbation and tight-binding methods. The effective mass approximation and electron motion in a periodic potential, Boltzmann transport equation and deformation potentials used for analysis of transport properties are discussed. Further, the book examines experiments and theoretical analyses of cyclotron resonance in detail. Optical and transport properties, magneto-transport, two-dimensional electron gas transport (HEMT and MOSFET) and quantum transport are reviewed, while optical transition, electron-phonon interaction and electron mobility are also addressed. Energy and electronic structure of a quantum dot (artificial atom) are explained with the help of Slater determinants. The...

  16. Semiconductor physics an introduction

    CERN Document Server

    Seeger, Karlheinz

    1999-01-01

    Semiconductor Physics - An Introduction - is suitable for the senior undergraduate or new graduate student majoring in electrical engineering or physics. It will also be useful to solid-state scientists and device engineers involved in semiconductor design and technology. The text provides a lucid account of charge transport, energy transport and optical processes, and a detailed description of many devices. It includes sections on superlattices and quantum well structures, the effects of deep-level impurities on transport, the quantum Hall effect and the calculation of the influence of a magnetic field on the carrier distribution function. This 6th edition has been revised and corrected, and new sections have been added to different chapters.

  17. Three dimensional strained semiconductors

    Science.gov (United States)

    Voss, Lars; Conway, Adam; Nikolic, Rebecca J.; Leao, Cedric Rocha; Shao, Qinghui

    2016-11-08

    In one embodiment, an apparatus includes a three dimensional structure comprising a semiconductor material, and at least one thin film in contact with at least one exterior surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the three dimensional structure. In another embodiment, a method includes forming a three dimensional structure comprising a semiconductor material, and depositing at least one thin film on at least one surface of the three dimensional structure for inducing a strain in the structure, the thin film being characterized as providing at least one of: an induced strain of at least 0.05%, and an induced strain in at least 5% of a volume of the structure.

  18. Compound semiconductor device modelling

    CERN Document Server

    Miles, Robert

    1993-01-01

    Compound semiconductor devices form the foundation of solid-state microwave and optoelectronic technologies used in many modern communication systems. In common with their low frequency counterparts, these devices are often represented using equivalent circuit models, but it is often necessary to resort to physical models in order to gain insight into the detailed operation of compound semiconductor devices. Many of the earliest physical models were indeed developed to understand the 'unusual' phenomena which occur at high frequencies. Such was the case with the Gunn and IMPATI diodes, which led to an increased interest in using numerical simulation methods. Contemporary devices often have feature sizes so small that they no longer operate within the familiar traditional framework, and hot electron or even quantum­ mechanical models are required. The need for accurate and efficient models suitable for computer aided design has increased with the demand for a wider range of integrated devices for operation at...

  19. Optically coupled semiconductor device

    Energy Technology Data Exchange (ETDEWEB)

    Kumagaya, Naoki

    1988-11-18

    This invention concerns an optically coupled semiconductor device using the light as input signal and a MOS transistor for the output side in order to control on-off of the output side by the input signal which is insulated from the output. Concerning this sort of element, when a MOS transistor and a load resistance are planned to be accumulated on the same chip, a resistor and control of impurity concentration of the channel, etc. become necessary despite that the only formation of a simple P-N junction is enough, for a solar cell, hence cost reduction thereof cannot be done. In order to remove this defect, this invention offers an optically coupled semiconductor device featuring that two solar cells are connected in reverse parallel between the gate sources of the output MOS transistors and an operational light emitting element is individually set facing a respective solar cell. 4 figs.

  20. Doping of organic semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Luessem, B.; Riede, M.; Leo, K. [Institut fuer Angewandte Photophysik, TU Dresden (Germany)

    2013-01-15

    The understanding and applications of organic semiconductors have shown remarkable progress in recent years. This material class has been developed from being a lab curiosity to the basis of first successful products as small organic LED (OLED) displays; other areas of application such as OLED lighting and organic photovoltaics are on the verge of broad commercialization. Organic semiconductors are superior to inorganic ones for low-cost and large-area optoelectronics due to their flexibility, easy deposition, and broad variety, making tailor-made materials possible. However, electrical doping of organic semiconductors, i.e. the controlled adjustment of Fermi level that has been extremely important to the success of inorganic semiconductors, is still in its infancy. This review will discuss recent work on both fundamental principles and applications of doping, focused primarily to doping of evaporated organic layers with molecular dopants. Recently, both p- and n-type molecular dopants have been developed that lead to efficient and stable doping of organic thin films. Due to doping, the conductivity of the doped layers increases several orders of magnitude and allows for quasi-Ohmic contacts between organic layers and metal electrodes. Besides reducing voltage losses, doping thus also gives design freedom in terms of transport layer thickness and electrode choice. The use of doping in applications like OLEDs and organic solar cells is highlighted in this review. Overall, controlled molecular doping can be considered as key enabling technology for many different organic device types that can lead to significant improvements in efficiencies and lifetimes. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  1. Images through semiconductors

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    Improved image processing techniques are constantly being developed for television and for scanners using X-rays or other radiation for industrial or medical applications, etc. As Erik Heijne of CERN explains here, particle physics too has its own special requirements for image processing. The increasing use of semiconductor techniques for handling measurements down to the level of a few microns provides another example of the close interplay between scientific research and technological development. (orig.).

  2. Muonium states in semiconductors

    International Nuclear Information System (INIS)

    Patterson, B.D.

    1987-01-01

    There is a brief summary of what is known about the muonium states isotropic, anisotropic and diamagnetic in diamond and zincblende semiconductors. The report deals with muonium spectroscopy, including the formation probabilities, hyperfine parameters and electronic g-factors of the states. The dynamics of the states is treated including a discussion of the transition from isotropic Mu to anisotropic Mu in diamond, temperature-dependent linewidthes in silicon and germanium and effects of daping and radiation damage

  3. Nonradiative recombination in semiconductors

    CERN Document Server

    Abakumov, VN; Yassievich, IN

    1991-01-01

    In recent years, great progress has been made in the understandingof recombination processes controlling the number of excessfree carriers in semiconductors under nonequilibrium conditions. As a result, it is now possible to give a comprehensivetheoretical description of these processes. The authors haveselected a number of experimental results which elucidate theunderlying physical problems and enable a test of theoreticalmodels. The following topics are dealt with: phenomenological theory ofrecombination, theoretical models of shallow and deep localizedstates, cascade model of carrier captu

  4. Doping of organic semiconductors

    International Nuclear Information System (INIS)

    Luessem, B.; Riede, M.; Leo, K.

    2013-01-01

    The understanding and applications of organic semiconductors have shown remarkable progress in recent years. This material class has been developed from being a lab curiosity to the basis of first successful products as small organic LED (OLED) displays; other areas of application such as OLED lighting and organic photovoltaics are on the verge of broad commercialization. Organic semiconductors are superior to inorganic ones for low-cost and large-area optoelectronics due to their flexibility, easy deposition, and broad variety, making tailor-made materials possible. However, electrical doping of organic semiconductors, i.e. the controlled adjustment of Fermi level that has been extremely important to the success of inorganic semiconductors, is still in its infancy. This review will discuss recent work on both fundamental principles and applications of doping, focused primarily to doping of evaporated organic layers with molecular dopants. Recently, both p- and n-type molecular dopants have been developed that lead to efficient and stable doping of organic thin films. Due to doping, the conductivity of the doped layers increases several orders of magnitude and allows for quasi-Ohmic contacts between organic layers and metal electrodes. Besides reducing voltage losses, doping thus also gives design freedom in terms of transport layer thickness and electrode choice. The use of doping in applications like OLEDs and organic solar cells is highlighted in this review. Overall, controlled molecular doping can be considered as key enabling technology for many different organic device types that can lead to significant improvements in efficiencies and lifetimes. (Copyright copyright 2013 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Isotopically controlled semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    Haller, Eugene E.

    2006-06-19

    The following article is an edited transcript based on the Turnbull Lecture given by Eugene E. Haller at the 2005 Materials Research Society Fall Meeting in Boston on November 29, 2005. The David Turnbull Lectureship is awarded to recognize the career of a scientist who has made outstanding contributions to understanding materials phenomena and properties through research, writing, and lecturing, as exemplified by the life work of David Turnbull. Haller was named the 2005 David Turnbull Lecturer for his 'pioneering achievements and leadership in establishing the field of isotopically engineered semiconductors; for outstanding contributions to materials growth, doping and diffusion; and for excellence in lecturing, writing, and fostering international collaborations'. The scientific interest, increased availability, and technological promise of highly enriched isotopes have led to a sharp rise in the number of experimental and theoretical studies with isotopically controlled semiconductor crystals. This article reviews results obtained with isotopically controlled semiconductor bulk and thin-film heterostructures. Isotopic composition affects several properties such as phonon energies, band structure, and lattice constant in subtle, but, for their physical understanding, significant ways. Large isotope-related effects are observed for thermal conductivity in local vibrational modes of impurities and after neutron transmutation doping. Spectacularly sharp photoluminescence lines have been observed in ultrapure, isotopically enriched silicon crystals. Isotope multilayer structures are especially well suited for simultaneous self- and dopant-diffusion studies. The absence of any chemical, mechanical, or electrical driving forces makes possible the study of an ideal random-walk problem. Isotopically controlled semiconductors may find applications in quantum computing, nanoscience, and spintronics.

  6. Wireless Multiplexed Surface Acoustic Wave Sensors Project

    Science.gov (United States)

    Youngquist, Robert C.

    2014-01-01

    Wireless Surface Acoustic Wave (SAW) Sensor is a new technology for obtaining multiple, real-time measurements under extreme environmental conditions. This project plans to develop a wireless multiplexed sensor system that uses SAW sensors, with no batteries or semiconductors, that are passive and rugged, can operate down to cryogenic temperatures and up to hundreds of degrees C, and can be used to sense a wide variety of parameters over reasonable distances (meters).

  7. Salt Tolerance

    OpenAIRE

    Xiong, Liming; Zhu, Jian-Kang

    2002-01-01

    Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are sh...

  8. Defect-Tolerant Monolayer Transition Metal Dichalcogenides

    DEFF Research Database (Denmark)

    Pandey, Mohnish; Rasmussen, Filip Anselm; Kuhar, Korina

    2016-01-01

    Localized electronic states formed inside the band gap of a semiconductor due to crystal defects can be detrimental to the material's optoelectronic properties. Semiconductors with a lower tendency to form defect induced deep gap states are termed defect-tolerant. Here we provide a systematic first...... the gap. These ideas are made quantitative by introducing a descriptor that measures the degree of similarity of the conduction and valence band manifolds. Finally, the study is generalized to nonpolar nanoribbons of the TMDs where we find that only the defect sensitive materials form edge states within......-principles investigation of defect tolerance in 29 monolayer transition metal dichalcogenides (TMDs) of interest for nanoscale optoelectronics. We find that the TMDs based on group VI and X metals form deep gap states upon creation of a chalcogen (S, Se, Te) vacancy, while the TMDs based on group IV metals form only...

  9. Survey of semiconductor physics

    CERN Document Server

    Böer, Karl W

    1992-01-01

    Any book that covers a large variety of subjects and is written by one author lacks by necessity the depth provided by an expert in his or her own field of specialization. This book is no exception. It has been written with the encouragement of my students and colleagues, who felt that an extensive card file I had accumulated over the years of teaching solid state and semiconductor physics would be helpful to more than just a few of us. This file, updated from time to time, contained lecture notes and other entries that were useful in my research and permitted me to give to my students a broader spectrum of information than is available in typical textbooks. When assembling this material into a book, I divided the top­ ics into material dealing with the homogeneous semiconductor, the subject of the previously published Volume 1, and the inhomoge­ neous semiconductor, the subject of this Volume 2. In order to keep the book to a manageable size, sections of tutorial character which can be used as text for a g...

  10. Semiconductor Ion Implanters

    International Nuclear Information System (INIS)

    MacKinnon, Barry A.; Ruffell, John P.

    2011-01-01

    In 1953 the Raytheon CK722 transistor was priced at $7.60. Based upon this, an Intel Xeon Quad Core processor containing 820,000,000 transistors should list at $6.2 billion! Particle accelerator technology plays an important part in the remarkable story of why that Intel product can be purchased today for a few hundred dollars. Most people of the mid twentieth century would be astonished at the ubiquity of semiconductors in the products we now buy and use every day. Though relatively expensive in the nineteen fifties they now exist in a wide range of items from high-end multicore microprocessors like the Intel product to disposable items containing 'only' hundreds or thousands like RFID chips and talking greeting cards. This historical development has been fueled by continuous advancement of the several individual technologies involved in the production of semiconductor devices including Ion Implantation and the charged particle beamlines at the heart of implant machines. In the course of its 40 year development, the worldwide implanter industry has reached annual sales levels around $2B, installed thousands of dedicated machines and directly employs thousands of workers. It represents in all these measures, as much and possibly more than any other industrial application of particle accelerator technology. This presentation discusses the history of implanter development. It touches on some of the people involved and on some of the developmental changes and challenges imposed as the requirements of the semiconductor industry evolved.

  11. The Physics of Semiconductors

    Science.gov (United States)

    Brennan, Kevin F.

    1999-02-01

    Modern fabrication techniques have made it possible to produce semiconductor devices whose dimensions are so small that quantum mechanical effects dominate their behavior. This book describes the key elements of quantum mechanics, statistical mechanics, and solid-state physics that are necessary in understanding these modern semiconductor devices. The author begins with a review of elementary quantum mechanics, and then describes more advanced topics, such as multiple quantum wells. He then disusses equilibrium and nonequilibrium statistical mechanics. Following this introduction, he provides a thorough treatment of solid-state physics, covering electron motion in periodic potentials, electron-phonon interaction, and recombination processes. The final four chapters deal exclusively with real devices, such as semiconductor lasers, photodiodes, flat panel displays, and MOSFETs. The book contains many homework exercises and is suitable as a textbook for electrical engineering, materials science, or physics students taking courses in solid-state device physics. It will also be a valuable reference for practicing engineers in optoelectronics and related areas.

  12. Study of defects in radiation tolerant semiconductor SiC

    Energy Technology Data Exchange (ETDEWEB)

    Itoh, Hisayoshi; Kawasuso, Atsuo; Ohshima, Takeshi; Yoshikawa, Masahito; Nashiyama, Isamu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Okumura, Hajime; Yoshida, Sadafumi

    1997-03-01

    Electron spin resonance (ESR) was used to study defects introduced in n-type 6H-SiC by 3 MeV electron irradiation. Two ESR signals labeled A and B related to radiation induced defects were observed. An ESR signal B can be explained by a fine interaction with an effective spin S=1. The g and D tensors of the signal B were found to be axially symmetric along the c-axis. The principal values of the g were obtained to be g parallel = 2.003 and g perpendicular = 2.008, and the absolute value of the D was 3.96x10{sup -2} cm{sup -1} at 100 K for this signal. It was also found that the value |D| decreased with increasing temperature. Isochronal annealing showed that the A and B centers have annealing stages of {approx_equal}200degC and {approx_equal}800degC, respectively. Tentative structural models are discussed for these ESR centers. (author)

  13. Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor Failure Conditions

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, P.C.; Vilathgamuwa, D.M.

    2007-01-01

    reconfigure the gating signals in order to tolerate the failed semiconductor devices without significantly decreasing the ac output quality and amplitude by properly using the inherent boost characteristic of Z-source network. In addition, the Z-source dual inverters can maintain the zero common mode voltage...... under semiconductor failure conditions, which is the unique characteristic attained by the dual inverters only. Lastly, all theoretical findings are verified in PLECS simulations....

  14. Biological and medical sensor technologies

    CERN Document Server

    Iniewski, Krzysztof

    2012-01-01

    Biological and Medical Sensor Technologies presents contributions from top experts who explore the development and implementation of sensors for various applications used in medicine and biology. Edited by a pioneer in the area of advanced semiconductor materials, the book is divided into two sections. The first part covers sensors for biological applications. Topics include: Advanced sensing and communication in the biological world DNA-derivative architectures for long-wavelength bio-sensing Label-free silicon photonics Quartz crystal microbalance-based biosensors Lab-on-chip technologies fo

  15. Methods and apparatuses for low-noise magnetic sensors

    KAUST Repository

    Kosel, Jü rgen; Sun, Jian

    2015-01-01

    Magnetic sensors are disclosed, as well as methods for fabricating and using the same. In some embodiments, an EMR effect sensor includes a semiconductor layer. In some embodiments, the EMR effect sensor may include a conductive layer substantially coupled to the semiconductor layer. In some embodiments, the EMR effect sensor may include a first voltage lead coupled to the semiconductor layer. In some embodiments, the first voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. In some embodiments, the EMR effect sensor may include a second voltage lead coupled to the conductive layer. In some embodiments, the second voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. Embodiments of a Hall effect sensor having the same or similar structure are also disclosed.

  16. Methods and apparatuses for low-noise magnetic sensors

    KAUST Repository

    Kosel, Jurgen

    2015-10-20

    Magnetic sensors are disclosed, as well as methods for fabricating and using the same. In some embodiments, an EMR effect sensor includes a semiconductor layer. In some embodiments, the EMR effect sensor may include a conductive layer substantially coupled to the semiconductor layer. In some embodiments, the EMR effect sensor may include a first voltage lead coupled to the semiconductor layer. In some embodiments, the first voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. In some embodiments, the EMR effect sensor may include a second voltage lead coupled to the conductive layer. In some embodiments, the second voltage lead may be configured to provide a voltage for measurement by a voltage measurement circuit. Embodiments of a Hall effect sensor having the same or similar structure are also disclosed.

  17. A Pascalian lateral drift sensor

    International Nuclear Information System (INIS)

    Jansen, H.

    2016-01-01

    A novel concept of a layer-wise produced semiconductor sensor for precise particle tracking is proposed herein. In contrast to common semiconductor sensors, local regions with increased doping concentration deep in the bulk termed charge guides increase the lateral drift of free charges on their way to the read-out electrode. This lateral drift enables charge sharing independent of the incident position of the traversing particle. With a regular grid of charge guides the lateral charge distribution resembles a normalised Pascal's triangle for particles that are stopped in depths lower than the depth of the first layer of the charge guides. For minimum ionising particles a sum of binomial distributions describes the lateral charge distribution. This concept decouples the achievable sensor resolution from the pitch size as the characteristic length is replaced by the lateral distance of the charge guides.

  18. A Pascalian lateral drift sensor

    Energy Technology Data Exchange (ETDEWEB)

    Jansen, H., E-mail: hendrik.jansen@desy.de

    2016-09-21

    A novel concept of a layer-wise produced semiconductor sensor for precise particle tracking is proposed herein. In contrast to common semiconductor sensors, local regions with increased doping concentration deep in the bulk termed charge guides increase the lateral drift of free charges on their way to the read-out electrode. This lateral drift enables charge sharing independent of the incident position of the traversing particle. With a regular grid of charge guides the lateral charge distribution resembles a normalised Pascal's triangle for particles that are stopped in depths lower than the depth of the first layer of the charge guides. For minimum ionising particles a sum of binomial distributions describes the lateral charge distribution. This concept decouples the achievable sensor resolution from the pitch size as the characteristic length is replaced by the lateral distance of the charge guides.

  19. Basic opto-electronics on silicon for sensor applications

    NARCIS (Netherlands)

    Joppe, J.L.; Bekman, H.H.P.Th.; de Krijger, A.J.T.; Albers, H.; Chalmers, J.; Chalmers, J.D.; Holleman, J.; Ikkink, T.J.; Ikkink, T.; van Kranenburg, H.; Zhou, M.-J.; Zhou, Ming-Jiang; Lambeck, Paul

    1994-01-01

    A general platform for integrated opto-electronic sensor systems on silicon is proposed. The system is based on a hybridly integrated semiconductor laser, ZnO optical waveguides and monolithic photodiodes and electronic circuiry.

  20. Infectious Tolerance

    OpenAIRE

    Jonuleit, Helmut; Schmitt, Edgar; Kakirman, Hacer; Stassen, Michael; Knop, Jürgen; Enk, Alexander H.

    2002-01-01

    Regulatory CD4+CD25+ T cells (Treg) are mandatory for maintaining immunologic self-tolerance. We demonstrate that the cell-cell contact–mediated suppression of conventional CD4+ T cells by human CD25+ Treg cells is fixation resistant, independent from membrane-bound TGF-β but requires activation and protein synthesis of CD25+ Treg cells. Coactivation of CD25+ Treg cells with Treg cell–depleted CD4+ T cells results in anergized CD4+ T cells that in turn inhibit the activation of conventional, ...

  1. 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

  2. TCT characterization of different semiconductor materials for particle detection

    International Nuclear Information System (INIS)

    Fink, J.; Lodomez, P.; Krueger, H.; Pernegger, H.; Weilhammer, P.; Wermes, N.

    2006-01-01

    The development of digital semiconductor based X-ray detectors necessitates a detailed understanding of the applied sensor material. Under this premise a broad-band transient current technique (TCT) setup has been developed and used to characterize different semiconductors. The measurements are based on the generation of electrical charges within the sensor material and the subsequent time-resolved analysis of the charge carrier movement. From the recorded current pulses the charge collection efficiency, the charge carrier mobility and the electric field profile have been extracted. The examined materials are silicon p in n diodes, ohmic and Schottky contacted CdTe detectors, CdZnTe (CZT) crystals with Schottky contacts as well as two single-crystal CVD-diamonds

  3. Thin film transistors for flexible electronics: Contacts, dielectrics and semiconductors

    KAUST Repository

    Quevedo-López, Manuel Angel Quevedo

    2011-06-01

    The development of low temperature, thin film transistor processes that have enabled flexible displays also present opportunities for flexible electronics and flexible integrated systems. Of particular interest are possible applications in flexible sensor systems for unattended ground sensors, smart medical bandages, electronic ID tags for geo-location, conformal antennas, radiation detectors, etc. In this paper, we review the impact of gate dielectrics, contacts and semiconductor materials on thin film transistors for flexible electronics applications. We present our recent results to fully integrate hybrid complementary metal oxide semiconductors comprising inorganic and organic-based materials. In particular, we demonstrate novel gate dielectric stacks and semiconducting materials. The impact of source and drain contacts on device performance is also discussed. Copyright © 2011 American Scientific Publishers.

  4. Thin film transistors for flexible electronics: Contacts, dielectrics and semiconductors

    KAUST Repository

    Quevedo-Ló pez, Manuel Angel Quevedo; Wondmagegn, Wudyalew T.; Alshareef, Husam N.; Ramí rez-Bon, Rafael; Gnade, Bruce E.

    2011-01-01

    The development of low temperature, thin film transistor processes that have enabled flexible displays also present opportunities for flexible electronics and flexible integrated systems. Of particular interest are possible applications in flexible sensor systems for unattended ground sensors, smart medical bandages, electronic ID tags for geo-location, conformal antennas, radiation detectors, etc. In this paper, we review the impact of gate dielectrics, contacts and semiconductor materials on thin film transistors for flexible electronics applications. We present our recent results to fully integrate hybrid complementary metal oxide semiconductors comprising inorganic and organic-based materials. In particular, we demonstrate novel gate dielectric stacks and semiconducting materials. The impact of source and drain contacts on device performance is also discussed. Copyright © 2011 American Scientific Publishers.

  5. Infectious Tolerance

    Science.gov (United States)

    Jonuleit, Helmut; Schmitt, Edgar; Kakirman, Hacer; Stassen, Michael; Knop, Jürgen; Enk, Alexander H.

    2002-01-01

    Regulatory CD4+CD25+ T cells (Treg) are mandatory for maintaining immunologic self-tolerance. We demonstrate that the cell-cell contact–mediated suppression of conventional CD4+ T cells by human CD25+ Treg cells is fixation resistant, independent from membrane-bound TGF-β but requires activation and protein synthesis of CD25+ Treg cells. Coactivation of CD25+ Treg cells with Treg cell–depleted CD4+ T cells results in anergized CD4+ T cells that in turn inhibit the activation of conventional, freshly isolated CD4+ T helper (Th) cells. This infectious suppressive activity, transferred from CD25+ Treg cells via cell contact, is cell contact–independent and partially mediated by soluble transforming growth factor (TGF)-β. The induction of suppressive properties in conventional CD4+ Th cells represents a mechanism underlying the phenomenon of infectious tolerance. This explains previously published conflicting data on the role of TGF-β in CD25+ Treg cell–induced immunosuppression. PMID:12119350

  6. Layered semiconductor neutron detectors

    Science.gov (United States)

    Mao, Samuel S; Perry, Dale L

    2013-12-10

    Room temperature operating solid state hand held neutron detectors integrate one or more relatively thin layers of a high neutron interaction cross-section element or materials with semiconductor detectors. The high neutron interaction cross-section element (e.g., Gd, B or Li) or materials comprising at least one high neutron interaction cross-section element can be in the form of unstructured layers or micro- or nano-structured arrays. Such architecture provides high efficiency neutron detector devices by capturing substantially more carriers produced from high energy .alpha.-particles or .gamma.-photons generated by neutron interaction.

  7. Basic properties of semiconductors

    CERN Document Server

    Landsberg, PT

    2013-01-01

    Since Volume 1 was published in 1982, the centres of interest in the basic physics of semiconductors have shifted. Volume 1 was called Band Theory and Transport Properties in the first edition, but the subject has broadened to such an extent that Basic Properties is now a more suitable title. Seven chapters have been rewritten by the original authors. However, twelve chapters are essentially new, with the bulk of this work being devoted to important current topics which give this volume an almost encyclopaedic form. The first three chapters discuss various aspects of modern band theory and the

  8. 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.

  9. Semiconductor ionizino. radiation detectors

    International Nuclear Information System (INIS)

    1982-01-01

    Spectrometric semiconductor detectors of ionizing radiation with the electron-hole junction, based on silicon and germanium are presented. The following parameters are given for the individual types of germanium detectors: energy range of detected radiation, energy resolution given as full width at half maximum (FWHM) and full width at one tenth of maximum (FWTM) for 57 Co and 60 Co, detection sensitivity, optimal voltage, and electric capacitance at optimal voltage. For silicon detectors the value of FWHM for 239 Pu is given, the sensitive area and the depth of the sensitive area. (E.S.)

  10. Band structure of semiconductors

    CERN Document Server

    Tsidilkovski, I M

    2013-01-01

    Band Structure of Semiconductors provides a review of the theoretical and experimental methods of investigating band structure and an analysis of the results of the developments in this field. The book presents the problems, methods, and applications in the study of band structure. Topics on the computational methods of band structure; band structures of important semiconducting materials; behavior of an electron in a perturbed periodic field; effective masses and g-factors for the most commonly encountered band structures; and the treatment of cyclotron resonance, Shubnikov-de Haas oscillatio

  11. Empowering smartphone users with sensor node for air quality measurement

    Science.gov (United States)

    Oletic, Dinko; Bilas, Vedran

    2013-06-01

    We present an architecture of a sensor node developed for use with smartphones for participatory sensing of air quality in urban environments. Our solution features inexpensive metal-oxide semiconductor gas sensors (MOX) for measurement of CO, O3, NO2 and VOC, along with sensors for ambient temperature and humidity. We focus on our design of sensor interface consisting of power-regulated heater temperature control, and the design of resistance sensing circuit. Accuracy of the sensor interface is characterized. Power consumption of the sensor node is analysed. Preliminary data obtained from the CO gas sensors in laboratory conditions and during the outdoor field-test is shown.

  12. Empowering smartphone users with sensor node for air quality measurement

    International Nuclear Information System (INIS)

    Oletic, Dinko; Bilas, Vedran

    2013-01-01

    We present an architecture of a sensor node developed for use with smartphones for participatory sensing of air quality in urban environments. Our solution features inexpensive metal-oxide semiconductor gas sensors (MOX) for measurement of CO, O 3 , NO 2 and VOC, along with sensors for ambient temperature and humidity. We focus on our design of sensor interface consisting of power-regulated heater temperature control, and the design of resistance sensing circuit. Accuracy of the sensor interface is characterized. Power consumption of the sensor node is analysed. Preliminary data obtained from the CO gas sensors in laboratory conditions and during the outdoor field-test is shown.

  13. Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

    Science.gov (United States)

    Hunter, Gary W.

    2005-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, and fire detection. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors; 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity; 3) The development of high temperature semiconductors, especially silicon carbide. This presentation discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  14. Synthesis, Characterization, and Ultrafast Dynamics of Metal, Metal Oxide, and Semiconductor Nanomaterials

    OpenAIRE

    Wheeler, Damon Andreas

    2013-01-01

    SYNTHESIS, CHARACTERIZATION, AND ULTRAFAST DYNAMICS OF METAL, METAL OXIDE, AND SEMICONDUCTOR NANOMATERIALSABSTRACTThe optical properties of each of the three main classes of inorganic nanomaterials, metals, metal oxides, and semiconductors differ greatly due to the intrinsically different nature of the materials. These optical properties are among the most fascinating and useful aspects of nanomaterials with applications spanning cancer treatment, sensors, lasers, and solar cells. One techn...

  15. 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

  16. ATLAS silicon microstrip Semiconductor Tracker (SCT)

    International Nuclear Information System (INIS)

    Unno, Y.

    2000-01-01

    Silicon microstrip semiconductor tracking system (SCT) will be in operation in the ATLAS detector in the Large Hadron Collider (LHC) at CERN. Challenging issues in the SCT are the radiation tolerance to the fluence of 2x10 14 1-MeV-neutron-equivalent particles/cm 2 at the designed luminosity of 1x10 34 cm -2 /s of the proton-proton collisions and the speed of the electronics to identify the crossing bunches at 25 ns. The developments and the status of the SCT are presented from the point of view of these issues. Series production of the SCT will start in the year 2001 and the SCT will be installed into the ATLAS detector during 2003-2004

  17. Analysis of fluctuations in semiconductor devices

    Science.gov (United States)

    Andrei, Petru

    The random nature of ion implantation and diffusion processes as well as inevitable tolerances in fabrication result in random fluctuations of doping concentrations and oxide thickness in semiconductor devices. These fluctuations are especially pronounced in ultrasmall (nanoscale) semiconductor devices when the spatial scale of doping and oxide thickness variations become comparable with the geometric dimensions of devices. In the dissertation, the effects of these fluctuations on device characteristics are analyzed by using a new technique for the analysis of random doping and oxide thickness induced fluctuations. This technique is universal in nature in the sense that it is applicable to any transport model (drift-diffusion, semiclassical transport, quantum transport etc.) and it can be naturally extended to take into account random fluctuations of the oxide (trapped) charges and channel length. The technique is based on linearization of the transport equations with respect to the fluctuating quantities. It is computationally much (a few orders of magnitude) more efficient than the traditional Monte-Carlo approach and it yields information on the sensitivity of fluctuations of parameters of interest (e.g. threshold voltage, small-signal parameters, cut-off frequencies, etc.) to the locations of doping and oxide thickness fluctuations. For this reason, it can be very instrumental in the design of fluctuation-resistant structures of semiconductor devices. Quantum mechanical effects are taken into account by using the density-gradient model as well as through self-consistent Poisson-Schrodinger computations. Special attention is paid to the presenting of the technique in a form that is suitable for implementation on commercial device simulators. The numerical implementation of the technique is discussed in detail and numerous computational results are presented and compared with those previously published in literature.

  18. Low Power and High Sensitivity MOSFET-Based Pressure Sensor

    International Nuclear Information System (INIS)

    Zhang Zhao-Hua; Ren Tian-Ling; Zhang Yan-Hong; Han Rui-Rui; Liu Li-Tian

    2012-01-01

    Based on the metal-oxide-semiconductor field effect transistor (MOSFET) stress sensitive phenomenon, a low power MOSFET pressure sensor is proposed. Compared with the traditional piezoresistive pressure sensor, the present pressure sensor displays high performances on sensitivity and power consumption. The sensitivity of the MOSFET sensor is raised by 87%, meanwhile the power consumption is decreased by 20%. (cross-disciplinary physics and related areas of science and technology)

  19. II-VI semiconductor compounds

    CERN Document Server

    1993-01-01

    For condensed matter physicists and electronic engineers, this volume deals with aspects of II-VI semiconductor compounds. Areas covered include devices and applications of II-VI compounds; Co-based II-IV semi-magnetic semiconductors; and electronic structure of strained II-VI superlattices.

  20. Electronic structure of semiconductor interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Herman, F

    1983-02-01

    The study of semiconductor interfaces is one of the most active and exciting areas of current semiconductor research. Because interfaces play a vital role in modern semiconductor technology (integrated circuits, heterojunction lasers, solar cells, infrared detectors, etc.), there is a strong incentive to understand interface properties at a fundamental level and advance existing technology thereby. At the same time, technological advances such as molecular beam epitaxy have paved the way for the fabrication of semiconductor heterojunctions and superlattices of novel design which exhibit unusual electronic, optical, and magnetic properties and offer unique opportunities for fundamental scientific research. A general perspective on this subject is offered treating such topics as the atomic and electronic structure of semiconductor surfaces and interfaces; oxidation and oxide layers; semiconductor heterojunctions and superlattices; rectifying metal-semiconductor contacts; and interface reactions. Recent progress is emphasized and some future directions are indicated. In addition, the role that large-scale scientific computation has played in furthering our theoretical understanding of semiconductor surfaces and interfaces is discussed. Finally, the nature of theoretical models, and the role they play in describing the physical world is considered.

  1. Quantum transport in semiconductor nanowires

    NARCIS (Netherlands)

    Van Dam, J.

    2006-01-01

    This thesis describes a series of experiments aimed at understanding the low-temperature electrical transport properties of semiconductor nanowires. The semiconductor nanowires (1-100 nm in diameter) are grown from nanoscale gold particles via a chemical process called vapor-liquid-solid (VLS)

  2. Semiconductor photocatalysis principles and applications

    CERN Document Server

    Kisch, Horst

    2014-01-01

    Focusing on the basic principles of semiconductor photocatalysis, this book also gives a brief introduction to photochemistry, photoelectrochemistry, and homogeneous photocatalysis. In addition, the author - one of the leading authorities in the field - presents important environmental and practical aspects. A valuable, one-stop source for all chemists, material scientists, and physicists working in this area, as well as novice researchers entering semiconductor photocatalysis.

  3. Progress in semiconductor drift detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Walton, J.; Gatti, E.

    1985-01-01

    Progress in testing semiconductor drift detectors is reported. Generally better position and energy resolutions were obtained than resolutions published previously. The improvement is mostly due to new electronics better matched to different detectors. It is shown that semiconductor drift detectors are becoming versatile and reliable detectors for position and energy measurements

  4. Semiconductor materials and their properties

    NARCIS (Netherlands)

    Reinders, Angelina H.M.E.; Verlinden, Pierre; van Sark, Wilfried; Freundlich, Alexandre; Reinders, Angele; Verlinden, Pierre; van Sark, Wilfried; Freundlich, Alexandre

    2017-01-01

    Semiconductor materials are the basic materials which are used in photovoltaic (PV) devices. This chapter introduces solid-state physics and semiconductor properties that are relevant to photovoltaics without spending too much time on unnecessary information. Usually atoms in the group of

  5. Optical coherent control in semiconductors

    DEFF Research Database (Denmark)

    Østergaard, John Erland; Vadim, Lyssenko; Hvam, Jørn Märcher

    2001-01-01

    of quantum control including the recent applications to semiconductors and nanostructures. We study the influence of inhomogeneous broadening in semiconductors on CC results. Photoluminescence (PL) and the coherent emission in four-wave mixing (FWM) is recorded after resonant excitation with phase...

  6. 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....

  7. Electronic structure of semiconductor interfaces

    International Nuclear Information System (INIS)

    Herman, F.

    1983-01-01

    The study of semiconductor interfaces is one of the most active and exciting areas of current semiconductor research. Because interfaces play a vital role in modern semiconductor technology (integrated circuits, heterojunction lasers, solar cells, infrared detectors, etc.), there is a strong incentive to understand interface properties at a fundamental level and advance existing technology thereby. At the same time, technological advances such as molecular beam epitaxy have paved the way for the fabrication of semiconductor heterojunctions and superlattices of novel design which exhibit unusual electronic, optical, and magnetic properties and offer unique opportunities for fundamental scientific research. A general perspective on this subject is offered treating such topics as the atomic and electronic structure of semiconductor surfaces and interfaces; oxidation and oxide layers; semiconductor heterojunctions and superlattices; rectifying metal-semiconductor contacts; and interface reactions. Recent progress is emphasized and some future directions are indicated. In addition, the role that large-scale scientific computation has played in furthering our theoretical understanding of semiconductor surfaces and interfaces is discussed. Finally, the nature of theoretical models, and the role they play in describing the physical world is considered. (Author) [pt

  8. Rectification at Graphene-Semiconductor Interfaces: Zero-Gap Semiconductor-Based Diodes

    Directory of Open Access Journals (Sweden)

    S. Tongay

    2012-01-01

    Full Text Available Using current-voltage (I-V, capacitance-voltage (C-V, and electric-field-modulated Raman measurements, we report on the unique physics and promising technical applications associated with the formation of Schottky barriers at the interface of a one-atom-thick zero-gap semiconductor (graphene and conventional semiconductors. When chemical-vapor-deposited graphene is transferred onto n-type Si, GaAs, 4H-SiC, and GaN semiconductor substrates, there is a strong van-der-Waals attraction that is accompanied by charge transfer across the interface and the formation of a rectifying (Schottky barrier. Thermionic-emission theory in conjunction with the Schottky-Mott model within the context of bond-polarization theory provides a surprisingly good description of the electrical properties. Applications can be made to sensors, where in forward bias there is exponential sensitivity to changes in the Schottky-barrier height due to the presence of absorbates on the graphene, and to analog devices, for which Schottky barriers are integral components. Such applications are promising because of graphene’s mechanical stability, its resistance to diffusion, its robustness at high temperatures, and its demonstrated capability to embrace multiple functionalities.

  9. Organic semiconductors in a spin

    CERN Document Server

    Samuel, I

    2002-01-01

    A little palladium can go a long way in polymer-based light-emitting diodes. Inorganic semiconductors such as silicon and gallium arsenide are essential for countless applications in everyday life, ranging from PCs to CD players. However, while they offer unrivalled computational speed, inorganic semiconductors are also rigid and brittle, which means that they are less suited to applications such as displays and flexible electronics. A completely different class of materials - organic semiconductors - are being developed for these applications. Organic semiconductors have many attractive features: they are easy to make, they can emit visible light, and there is tremendous scope for tailoring their properties to specific applications by changing their chemical structure. Research groups and companies around the world have developed a wide range of organic-semiconductor devices, including transistors, light-emitting diodes (LEDs), solar cells and lasers. (U.K.)

  10. Fault Tolerant Control: A Simultaneous Stabilization Result

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Blondel, V.D.

    2004-01-01

    This paper discusses the problem of designing fault tolerant compensators that stabilize a given system both in the nominal situation, as well as in the situation where one of the sensors or one of the actuators has failed. It is shown that such compensators always exist, provided that the system...... is detectable from each output and that it is stabilizable. The proof of this result is constructive, and a worked example shows how to design a fault tolerant compensator for a simple, yet challeging system. A family of second order systems is described that requires fault tolerant compensators of arbitrarily...

  11. Ion implantation for semiconductors

    International Nuclear Information System (INIS)

    Grey-Morgan, T.

    1995-01-01

    Full text: Over the past two decades, thousands of particle accelerators have been used to implant foreign atoms like boron, phosphorus and arsenic into silicon crystal wafers to produce special embedded layers for manufacturing semiconductor devices. Depending on the device required, the atomic species, the depth of implant and doping levels are the main parameters for the implantation process; the selection and parameter control is totally automated. The depth of the implant, usually less than 1 micron, is determined by the ion energy, which can be varied between 2 and 600 keV. The ion beam is extracted from a Freeman or Bernas type ion source and accelerated to 60 keV before mass analysis. For higher beam energies postacceleration is applied up to 200 keV and even higher energies can be achieved by mass selecting multiplycharged ions, but with a corresponding reduction in beam output. Depending on the device to be manufactured, doping levels can range from 10 10 to 10 15 atoms/cm 2 and are controlled by implanter beam currents in the range up to 30mA; continuous process monitoring ensures uniformity across the wafer of better than 1 % . As semiconductor devices get smaller, additional sophistication is required in the design of the implanter. The silicon wafers charge electrically during implantation and this charge must be dissipated continuously to reduce the electrical stress in the device and avoid destructive electrical breakdown. Electron flood guns produce low energy electrons (below 10 electronvolts) to neutralize positive charge buildup and implanter design must ensure minimum contamination by other isotopic species and ensure low internal sputter rates. The pace of technology in the semiconductor industry is such that implanters are being built now for 256 Megabit circuits but which are only likely to be widely available five years from now. Several specialist companies manufacture implanter systems, each costing around US$5 million, depending on the

  12. Improvement of cosmic ray ruggedness of hybrid vehicles power semiconductor devices

    International Nuclear Information System (INIS)

    Nishida, Shuichi; Ohnishi, Toyokazu; Fujikawa, Touma; Nose, Noboru; Hamada, Kimimori; Shoji, Tomoyuki; Ishiko, Masayasu

    2010-01-01

    Power semiconductors which are used under high voltage conditions in HVs (Hybrid Vehicles) are required to have high destruction tolerance against cosmic rays as well as to meet conventional quality standards. In this paper, an SEB (Single Event Burnout) failure mechanism induced by cosmic rays in IGBTs (Insulated Gate Bipolar Transistors) was investigated. Through an optimized device design in which thyristor action was suppressed, the device destruction tolerance was greatly improved. (author)

  13. Radiation immune RAM semiconductor technology for the 80's. [Random Access Memory

    Science.gov (United States)

    Hanna, W. A.; Panagos, P.

    1983-01-01

    This paper presents current and short term future characteristics of RAM semiconductor technologies which were obtained by literature survey and discussions with cognizant Government and industry personnel. In particular, total ionizing dose tolerance and high energy particle susceptibility of the technologies are addressed. Technologies judged compatible with spacecraft applications are ranked to determine the best current and future technology for fast access (less than 60 ns), radiation tolerant RAM.

  14. Semiconductor radiation detector

    Science.gov (United States)

    Bell, Zane W.; Burger, Arnold

    2010-03-30

    A semiconductor detector for ionizing electromagnetic radiation, neutrons, and energetic charged particles. The detecting element is comprised of a compound having the composition I-III-VI.sub.2 or II-IV-V.sub.2 where the "I" component is from column 1A or 1B of the periodic table, the "II" component is from column 2B, the "III" component is from column 3A, the "IV" component is from column 4A, the "V" component is from column 5A, and the "VI" component is from column 6A. The detecting element detects ionizing radiation by generating a signal proportional to the energy deposited in the element, and detects neutrons by virtue of the ionizing radiation emitted by one or more of the constituent materials subsequent to capture. The detector may contain more than one neutron-sensitive component.

  15. Semiconductor testing method

    International Nuclear Information System (INIS)

    Brown, Stephen.

    1992-01-01

    In a method of avoiding use of nuclear radiation, eg gamma rays, X-rays, electron beams, for testing semiconductor components for resistance to hard radiation, which hard radiation causes data corruption in some memory devices and 'latch-up' in others, similar fault effects can be achieved using a xenon or other 'light' flash gun even though the penetration of light is significantly less than that of gamma rays. The method involves treating a device with gamma radiation, measuring a particular fault current at the onset of a fault event, repeating the test with light to confirm the occurrence of the fault event at the same measured fault current, and using the fault current value as a reference for future tests using light on similar devices. (author)

  16. 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.)

  17. Energy distribution in semiconductors

    International Nuclear Information System (INIS)

    Ance, C.

    1979-01-01

    For various semiconductors the dispersive energy Esub(d) defined in the Wemple-Didomenico model is connected with the covalent and ionic energies Esub(h) and C. A continuous curve of ionicity against the ratio of the two energies Esub(A) and Esub(B), connected to Esub(h) and C is reported. Afromowitz's model is applied to the ternary compounds Gasub(1-x)Alsub(x)Sb using optical decomposition. From these results the average energy gap Esub(g) is given by Esub(g) = D 0 M 0 sup((IB))/(epsilon 1 (0)-1) where M 0 sup((IB)) is the interband transition contribution to the optical moment M 0 . (author)

  18. Organic Semiconductor Photovoltaics

    Science.gov (United States)

    Sariciftci, Niyazi Serdar

    2005-03-01

    Recent developments on organic photovoltaic elements are reviewed. Semiconducting conjugated polymers and molecules as well as nanocrystalline inorganic semiconductors are used in composite thin films. The photophysics of such photoactive devices is based on the photoinduced charge transfer from donor type semiconducting molecules onto acceptor type molecules such as Buckminsterfullerene, C60 and/or nanoparticles. Similar to the first steps in natural photosynthesis, this photoinduced electron transfer leads to a number of potentially interesting applications which include sensitization of the photoconductivity and photovoltaic phenomena. Examples of photovoltaic architectures are discussed with their potential in terrestrial solar energy conversion. Several materials are introduced and discussed for their photovoltaic activities. Furthermore, nanomorphology has been investigated with AFM, SEM and TEM. The morphology/property relationship for a given photoactive system is found to be a major effect.

  19. Taste sensor; Mikaku sensor

    Energy Technology Data Exchange (ETDEWEB)

    Toko, K. [Kyushu University, Fukuoka (Japan)

    1998-03-05

    This paper introduces a taste sensor having a lipid/polymer membrane to work as a receptor of taste substances. The paper describes the following matters: this sensor uses a hollow polyvinyl chloride rod filled with KCl aqueous solution, and placed with silver and silver chloride wires, whose cross section is affixed with a lipid/polymer membrane as a lipid membrane electrode to identify taste from seven or eight kinds of response patterns of electric potential output from the lipid/polymer membrane; measurements of different substances presenting acidic taste, salty taste, bitter taste, sweet taste and flavor by using this sensor identified clearly each taste (similar response is shown to a similar taste even if the substances are different); different responses are indicated on different brands of beers; from the result of measuring a great variety of mineral waters, a possibility was suggested that this taste sensor could be used for water quality monitoring sensors; and application of this taste sensor may be expected as a maturation control sensor for Japanese sake (wine) and miso (bean paste) manufacturing. 2 figs., 1 tab.

  20. Repressive Tolerance

    DEFF Research Database (Denmark)

    Pedersen, Morten Jarlbæk

    2017-01-01

    Consultation of organised interests and others when drafting laws is often seen as an important source of both input and output legitimacy. But whereas the input side of the equation stems from the very process of listening to societal actors, output legitimacy can only be strengthened if consult......Consultation of organised interests and others when drafting laws is often seen as an important source of both input and output legitimacy. But whereas the input side of the equation stems from the very process of listening to societal actors, output legitimacy can only be strengthened...... a substantial effect on the substance of laws – shows that there is a great difference in the amenability of different branches of government but that, in general, authorities do not listen much despite a very strong consultation institution and tradition. A suggestion for an explanation could be pointing...... to an administrative culture of repressive tolerance of organised interests: authorities listen but only reacts in a very limited sense. This bears in it the risk of jeopardising the knowledge transfer from societal actors to administrative ditto thus harming the consultation institutions’ potential for strengthening...

  1. Beta particle detection efficiency of the radiation sensor made from a mixture of polyaniline and titanium oxide

    International Nuclear Information System (INIS)

    Tamura, M.; Miyata, H.; Katsumata, M.; Matsuda, K.; Ueno, T.; Ito, D.; Suzuki, T.

    2016-01-01

    We developed a new real-time radiation sensor using an organic semiconductor and measured its β-particle detection sensitivity. This sensor is fabricated by simply combining a p-type semiconductor, polyaniline (Pani), with an n-type semiconductor, TiO_2, and processing the compound. Since Pani and TiO_2 are both inexpensive materials, the sensor can be fabricated at a lower cost than inorganic semiconductor sensors. The signal of each fabricated sensor was measured by a charge sensitive ADC for the irradiation of β-particles. The response signal data of the ADC for each irradiation was measured to calculate the detection efficiency of the detector. The maximum detection efficiency measured as β-particle sensitivity of the sensor was 1%. This β-particle sensitivity is higher than that reported of Pani sensors in the past.

  2. Magnetic excitations in ferromagnetic semiconductors

    International Nuclear Information System (INIS)

    Furdyna, J.K.; Liu, X.; Zhou, Y.Y.

    2009-01-01

    Magnetic excitations in a series of GaMnAs ferromagnetic semiconductor films were studied by ferromagnetic resonance (FMR). Using the FMR approach, multi-mode spin wave resonance spectra have been observed, whose analysis provides information on magnetic anisotropy (including surface anisotropy), distribution of magnetization precession within the GaMnAs film, dynamic surface spin pinning (derived from surface anisotropy), and the value of exchange stiffness constant D. These studies illustrate a combination of magnetism and semiconductor physics that is unique to magnetic semiconductors

  3. 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.

  4. Microfabricated Chemical Sensors for Safety and Emission Control Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Chen, L.-Y.; Knight, D.; Liu, C. C.; Wu, Q. H.

    1998-01-01

    Chemical sensor technology is being developed for leak detection, emission monitoring, and fire safety applications. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication (MicroElectroMechanical Systems (MEMS)-based) technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Using these technologies, sensors to measure hydrogen, hydrocarbons, nitrogen oxides, carbon monoxide, oxygen, and carbon dioxide are being developed. A description is given of each sensor type and its present stage of development. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  5. State of the art in semiconductor detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.

    1990-01-01

    The state of the art in semiconductor detectors for elementary particle physics and X-ray astronomy is briefly reviewed. Semiconductor detectors are divided into two groups; i) classical semiconductor diode detectors and ii) semiconductor memory detectors. Principles of signal formation for both groups of detectors are described and their performance is compared. New developments of silicon detectors are reported here. (orig.)

  6. State of the art in semiconductor detectors

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.

    1989-01-01

    The state of the art in semiconductor detectors for elementary particle physics and x-ray astronomy is briefly reviewed. Semiconductor detectors are divided into two groups; classical semiconductor diode detectors; and semiconductor memory detectors. Principles of signal formation for both groups of detectors are described and their performance is compared. New developments of silicon detectors are reported here. 13 refs., 8 figs

  7. Semiconductor device comprising a pn-heterojunction

    NARCIS (Netherlands)

    2007-01-01

    An electric device is disclosed comprising a pn-heterojunction ( 4 ) formed by a nanowire ( 3 ) of 111 -V semiconductor material and a semiconductor body ( 1 ) comprising a group IV semiconductor material. The nanowire ( 3 ) is positioned in direct contact with the surface ( 2 ) of the semiconductor

  8. Toward designing semiconductor-semiconductor heterojunctions for photocatalytic applications

    Science.gov (United States)

    Zhang, Liping; Jaroniec, Mietek

    2018-02-01

    Semiconductor photocatalysts show a great potential for environmental and energy-related applications, however one of the major disadvantages is their relatively low photocatalytic performance due to the recombination of electron-hole pairs. Therefore, intensive research is being conducted toward design of heterojunctions, which have been shown to be effective for improving the charge-transfer properties and efficiency of photocatalysts. According to the type of band alignment and direction of internal electric field, heterojunctions are categorized into five different types, each of which is associated with its own charge transfer characteristics. Since the design of heterojunctions requires the knowledge of band edge positions of component semiconductors, the commonly used techniques for the assessment of band edge positions are reviewed. Among them the electronegativity-based calculation method is applied for a large number of popular visible-light-active semiconductors, including some widely investigated bismuth-containing semiconductors. On basis of the calculated band edge positions and the type of component semiconductors reported, heterojunctions composed of the selected bismuth-containing semiconductors are proposed. Finally, the most popular synthetic techniques for the fabrication of heterojunctions are briefly discussed.

  9. Method of manufacturing a semiconductor device and semiconductor device obtained with such a method

    NARCIS (Netherlands)

    2008-01-01

    The invention relates to a method of manufacturing a semiconductor device (10) with a semiconductor body (1) which is provided with at least one semiconductor element, wherein on the surface of the semiconductor body (1) a mesa- shaped semiconductor region (2) is formed, a masking layer (3) is

  10. Selective, electrochemical etching of a semiconductor

    Science.gov (United States)

    Dahal, Rajendra P.; Bhat, Ishwara B.; Chow, Tat-Sing

    2018-03-20

    Methods for facilitating fabricating semiconductor structures are provided which include: providing a multilayer structure including a semiconductor layer, the semiconductor layer including a dopant and having an increased conductivity; selectively increasing, using electrochemical processing, porosity of the semiconductor layer, at least in part, the selectively increasing porosity utilizing the increased conductivity of the semiconductor layer; and removing, at least in part, the semiconductor layer with the selectively increased porosity from the multilayer structure. By way of example, the selectively increasing porosity may include selectively, anodically oxidizing, at least in part, the semiconductor layer of the multilayer structure.

  11. -Net Approach to Sensor -Coverage

    Directory of Open Access Journals (Sweden)

    Fusco Giordano

    2010-01-01

    Full Text Available Wireless sensors rely on battery power, and in many applications it is difficult or prohibitive to replace them. Hence, in order to prolongate the system's lifetime, some sensors can be kept inactive while others perform all the tasks. In this paper, we study the -coverage problem of activating the minimum number of sensors to ensure that every point in the area is covered by at least sensors. This ensures higher fault tolerance, robustness, and improves many operations, among which position detection and intrusion detection. The -coverage problem is trivially NP-complete, and hence we can only provide approximation algorithms. In this paper, we present an algorithm based on an extension of the classical -net technique. This method gives an -approximation, where is the number of sensors in an optimal solution. We do not make any particular assumption on the shape of the areas covered by each sensor, besides that they must be closed, connected, and without holes.

  12. Sensor Compendium - A Snowmass Whitepaper-

    Energy Technology Data Exchange (ETDEWEB)

    Artuso, M. [Syracuse Univ., NY (United States); Battaglia, M. [Univ. of California, Santa Cruz, CA (United States); Bolla, G. [Purdue Univ., West Lafayette, IN (United States); Bortoletto, D. [Purdue Univ., West Lafayette, IN (United States); Caberera, B. [Stanford Univ., CA (United States); Carlstrom, J E [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Chang, C. L. [Univ. of Chicago, IL (United States); Argonne National Lab. (ANL), Argonne, IL (United States); Cooper, W. [Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States); Da Via, C. [Univ. of Manchester (United Kingdom); Demarteau, M. [Argonne National Lab. (ANL), Argonne, IL (United States); Fast, J. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Frisch, H. [Univ. of Chicago, IL (United States), et al.

    2013-10-01

    Sensors play a key role in detecting both charged particles and photons for all three frontiers in Particle Physics. The signals from an individual sensor that can be used include ionization deposited, phonons created, or light emitted from excitations of the material. The individual sensors are then typically arrayed for detection of individual particles or groups of particles. Mounting of new, ever higher performance experiments, often depend on advances in sensors in a range of performance characteristics. These performance metrics can include position resolution for passing particles, time resolution on particles impacting the sensor, and overall rate capabilities. In addition the feasible detector area and cost frequently provides a limit to what can be built and therefore is often another area where improvements are important. Finally, radiation tolerance is becoming a requirement in a broad array of devices. We present a status report on a broad category of sensors, including challenges for the future and work in progress to solve those challenges.

  13. Metal-insulator-semiconductor photodetectors.

    Science.gov (United States)

    Lin, Chu-Hsuan; Liu, Chee Wee

    2010-01-01

    The major radiation of the sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  14. Metal-Insulator-Semiconductor Photodetectors

    Directory of Open Access Journals (Sweden)

    Chu-Hsuan Lin

    2010-09-01

    Full Text Available The major radiation of the Sun can be roughly divided into three regions: ultraviolet, visible, and infrared light. Detection in these three regions is important to human beings. The metal-insulator-semiconductor photodetector, with a simpler process than the pn-junction photodetector and a lower dark current than the MSM photodetector, has been developed for light detection in these three regions. Ideal UV photodetectors with high UV-to-visible rejection ratio could be demonstrated with III-V metal-insulator-semiconductor UV photodetectors. The visible-light detection and near-infrared optical communications have been implemented with Si and Ge metal-insulator-semiconductor photodetectors. For mid- and long-wavelength infrared detection, metal-insulator-semiconductor SiGe/Si quantum dot infrared photodetectors have been developed, and the detection spectrum covers atmospheric transmission windows.

  15. 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...

  16. Atomic layer deposition for semiconductors

    CERN Document Server

    Hwang, Cheol Seong

    2014-01-01

    This edited volume discusses atomic layer deposition (ALD) for all modern semiconductor devices, moving from the basic chemistry of ALD and modeling of ALD processes to sections on ALD for memories, logic devices, and machines.

  17. Semiconductor technology program. Progress briefs

    Science.gov (United States)

    Bullis, W. M.

    1980-01-01

    Measurement technology for semiconductor materials, process control, and devices is reviewed. Activities include: optical linewidth and thermal resistance measurements; device modeling; dopant density profiles; resonance ionization spectroscopy; and deep level measurements. Standardized oxide charge terminology is also described.

  18. Semiconductor radiation detectors. Device physics

    International Nuclear Information System (INIS)

    Lutz, G.

    2007-01-01

    Starting from basic principles, the author, whose own contributions to these developments have been significant, describes the rapidly growing field of modern semiconductor detectors used for energy and position measurement radiation. This development was stimulated by requirements in elementary particle physics where it has led to important scientific discoveries. It has now spread to many other fields of science and technology. The book is written in a didactic way and includes an introduction to semiconductor physics. The working principles of semiconductor radiation detectors are explained in an intuitive way, followed by formal quantitative analysis. Broad coverage is also given to electronic signal readout and to the subject of radiation damage. The book is the first to comprehensively cover the semiconductor radiation detectors currently in use. It is useful as a teaching guide and as a reference work for research and applications. (orig.)

  19. Self-assembling peptide semiconductors

    Science.gov (United States)

    Tao, Kai; Makam, Pandeeswar; Aizen, Ruth; Gazit, Ehud

    2017-01-01

    Semiconductors are central to the modern electronics and optics industries. Conventional semiconductive materials bear inherent limitations, especially in emerging fields such as interfacing with biological systems and bottom-up fabrication. A promising candidate for bioinspired and durable nanoscale semiconductors is the family of self-assembled nanostructures comprising short peptides. The highly ordered and directional intermolecular π-π interactions and hydrogen-bonding network allow the formation of quantum confined structures within the peptide self-assemblies, thus decreasing the band gaps of the superstructures into semiconductor regions. As a result of the diverse architectures and ease of modification of peptide self-assemblies, their semiconductivity can be readily tuned, doped, and functionalized. Therefore, this family of electroactive supramolecular materials may bridge the gap between the inorganic semiconductor world and biological systems. PMID:29146781

  20. Temperature controller of semiconductor laser

    Czech Academy of Sciences Publication Activity Database

    Matoušek, Vít; Číp, Ondřej

    2003-01-01

    Roč. 73, č. 3 (2003), s. 10 - 12 ISSN 0928-5008 Institutional research plan: CEZ:AV0Z2065902 Keywords : temperature controller * semiconductor laser * laser diode Subject RIV: BH - Optics, Masers, Lasers

  1. Wake fields in semiconductor plasmas

    International Nuclear Information System (INIS)

    Berezhiani, V.I.; Mahajan, S.M.

    1994-05-01

    It is shown that an intense short laser pulse propagating through a semiconductor plasma will generated longitudinal Langmuir waves in its wake. The measurable wake field can be used as a diagnostic to study nonlinear optical phenomena. For narrow gap semiconductors (for examples InSb) with Kane-type dispersion relation, the system can simulate, at currently available laser powers, the physics underlying wake-field accelerators. (author). 9 refs, 1 fig

  2. Semiconductor research with reactor neutrons

    International Nuclear Information System (INIS)

    Kimura, Itsuro

    1992-01-01

    Reactor neutrons play an important role for characterization of semiconductor materials as same as other advanced materials. On the other hand reactor neutrons bring about not only malignant irradiation effects called radiation damage, but also useful effects such as neutron transmutation doping and defect formation for opto-electronics. Research works on semiconductor materials with the reactor neutrons of the Kyoto University Reactor (KUR) are briefly reviewed. In this review, a stress is laid on the present author's works. (author)

  3. Semiconductor crystal high resolution imager

    Science.gov (United States)

    Levin, Craig S. (Inventor); Matteson, James (Inventor)

    2011-01-01

    A radiation imaging device (10). The radiation image device (10) comprises a subject radiation station (12) producing photon emissions (14), and at least one semiconductor crystal detector (16) arranged in an edge-on orientation with respect to the emitted photons (14) to directly receive the emitted photons (14) and produce a signal. The semiconductor crystal detector (16) comprises at least one anode and at least one cathode that produces the signal in response to the emitted photons (14).

  4. Dissipative chaos in semiconductor superlattices

    Directory of Open Access Journals (Sweden)

    F. Moghadam

    2008-03-01

    Full Text Available In this paper the motion of electron in a miniband of a semiconductor superlattice (SSL under the influence of external electric and magnetic fields is investigated. The electric field is applied in a direction perpendicular to the layers of the semiconductor superlattice, and the magnetic field is applied in different direction Numerical calculations show conditions led to the possibility of chaotic behaviors.

  5. Reducing leakage current in semiconductor devices

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bin; Matioli, Elison de Nazareth; Palacios, Tomas Apostol

    2018-03-06

    A semiconductor device includes a first region having a first semiconductor material and a second region having a second semiconductor material. The second region is formed over the first region. The semiconductor device also includes a current blocking structure formed in the first region between first and second terminals of the semiconductor device. The current blocking structure is configured to reduce current flow in the first region between the first and second terminals.

  6. Optical orientation in ferromagnet/semiconductor hybrids

    International Nuclear Information System (INIS)

    Korenev, V L

    2008-01-01

    The physics of optical pumping of semiconductor electrons in ferromagnet/semiconductor hybrids is discussed. Optically oriented semiconductor electrons detect the magnetic state of a ferromagnetic film. In turn, the ferromagnetism of the hybrid can be controlled optically with the help of a semiconductor. Spin–spin interactions near the ferromagnet/semiconductor interface play a crucial role in the optical readout and the manipulation of ferromagnetism

  7. Optical orientation in ferromagnet/semiconductor hybrids

    Science.gov (United States)

    Korenev, V. L.

    2008-11-01

    The physics of optical pumping of semiconductor electrons in ferromagnet/semiconductor hybrids is discussed. Optically oriented semiconductor electrons detect the magnetic state of a ferromagnetic film. In turn, the ferromagnetism of the hybrid can be controlled optically with the help of a semiconductor. Spin-spin interactions near the ferromagnet/semiconductor interface play a crucial role in the optical readout and the manipulation of ferromagnetism.

  8. Optical Orientation in Ferromagnet/Semiconductor Hybrids

    OpenAIRE

    Korenev, V. L.

    2008-01-01

    The physics of optical pumping of semiconductor electrons in the ferromagnet/semiconductor hybrids is discussed. Optically oriented semiconductor electrons detect the magnetic state of the ferromagnetic film. In turn, the ferromagnetism of the hybrid can be controlled optically with the help of the semiconductor. Spin-spin interactions near the interface ferromagnet/semiconductor play crucial role in the optical readout and the manipulation of ferromagnetism.

  9. Design of fault tolerant control system for steam generator using

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Myung Ki; Seo, Mi Ro [Korea Electric Power Research Institute, Taejon (Korea, Republic of)

    1998-12-31

    A controller and sensor fault tolerant system for a steam generator is designed with fuzzy logic. A structure of the proposed fault tolerant redundant system is composed of a supervisor and two fuzzy weighting modulators. A supervisor alternatively checks a controller and a sensor induced performances to identify which part, a controller or a sensor, is faulty. In order to analyze controller induced performance both an error and a change in error of the system output are chosen as fuzzy variables. The fuzzy logic for a sensor induced performance uses two variables : a deviation between two sensor outputs and its frequency. Fuzzy weighting modulator generates an output signal compensated for faulty input signal. Simulations show that the proposed fault tolerant control scheme for a steam generator regulates well water level by suppressing fault effect of either controllers or sensors. Therefore through duplicating sensors and controllers with the proposed fault tolerant scheme, both a reliability of a steam generator control and sensor system and that of a power plant increase even more. 2 refs., 9 figs., 1 tab. (Author)

  10. Semiconductors for plasmonics and metamaterials

    DEFF Research Database (Denmark)

    Naik, G.V.; Boltasseva, Alexandra

    2010-01-01

    Plasmonics has conventionally been in the realm of metal-optics. However, conventional metals as plasmonic elements in the near-infrared (NIR) and visible spectral ranges suffer from problems such as large losses and incompatibility with semiconductor technology. Replacing metals with semiconduct......Plasmonics has conventionally been in the realm of metal-optics. However, conventional metals as plasmonic elements in the near-infrared (NIR) and visible spectral ranges suffer from problems such as large losses and incompatibility with semiconductor technology. Replacing metals...... with semiconductors can alleviate these problems if only semiconductors could exhibit negative real permittivity. Aluminum doped zinc oxide (AZO) is a low loss semiconductor that can show negative real permittivity in the NIR. A comparative assessment of AZO-based plasmonic devices such as superlens and hyperlens...... with their metal-based counterparts shows that AZO-based devices significantly outperform at a wavelength of 1.55 µm. This provides a strong stimulus in turning to semiconductor plasmonics at the telecommunication wavelengths. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)....

  11. Ripening of Semiconductor Nanoplatelets.

    Science.gov (United States)

    Ott, Florian D; Riedinger, Andreas; Ochsenbein, David R; Knüsel, Philippe N; Erwin, Steven C; Mazzotti, Marco; Norris, David J

    2017-11-08

    Ostwald ripening describes how the size distribution of colloidal particles evolves with time due to thermodynamic driving forces. Typically, small particles shrink and provide material to larger particles, which leads to size defocusing. Semiconductor nanoplatelets, thin quasi-two-dimensional (2D) particles with thicknesses of only a few atomic layers but larger lateral dimensions, offer a unique system to investigate this phenomenon. Experiments show that the distribution of nanoplatelet thicknesses does not defocus during ripening, but instead jumps sequentially from m to (m + 1) monolayers, allowing precise thickness control. We investigate how this counterintuitive process occurs in CdSe nanoplatelets. We develop a microscopic model that treats the kinetics and thermodynamics of attachment and detachment of monomers as a function of their concentration. We then simulate the growth process from nucleation through ripening. For a given thickness, we observe Ostwald ripening in the lateral direction, but none perpendicular. Thicker populations arise instead from nuclei that capture material from thinner nanoplatelets as they dissolve laterally. Optical experiments that attempt to track the thickness and lateral extent of nanoplatelets during ripening appear consistent with these conclusions. Understanding such effects can lead to better synthetic control, enabling further exploration of quasi-2D nanomaterials.

  12. 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.

  13. Semiconductor integrated circuits

    International Nuclear Information System (INIS)

    Michel, A.E.; Schwenker, R.O.; Ziegler, J.F.

    1979-01-01

    An improved method involving ion implantation to form non-epitaxial semiconductor integrated circuits. These are made by forming a silicon substrate of one conductivity type with a recessed silicon dioxide region extending into the substrate and enclosing a portion of the silicon substrate. A beam of ions of opposite conductivity type impurity is directed at the substrate at an energy and dosage level sufficient to form a first region of opposite conductivity within the silicon dioxide region. This impurity having a concentration peak below the surface of the substrate forms a region of the one conductivity type which extends from the substrate surface into the first opposite type region to a depth between the concentration peak and the surface and forms a second region of opposite conductivity type. The method, materials and ion beam conditions are detailed. Vertical bipolar integrated circuits can be made this way when the first opposite type conductivity region will function as a collector. Also circuits with inverted bipolar devices when this first region functions as a 'buried'' emitter region. (U.K.)

  14. Impurity gettering in semiconductors

    Science.gov (United States)

    Sopori, Bhushan L.

    1995-01-01

    A process for impurity gettering in a semiconductor substrate or device such as a silicon substrate or device. The process comprises hydrogenating the substrate or device at the back side thereof with sufficient intensity and for a time period sufficient to produce a damaged back side. Thereafter, the substrate or device is illuminated with electromagnetic radiation at an intensity and for a time period sufficient to cause the impurities to diffuse to the back side and alloy with a metal there present to form a contact and capture the impurities. The impurity gettering process also can function to simultaneously passivate defects within the substrate or device, with the defects likewise diffusing to the back side for simultaneous passivation. Simultaneously, substantially all hydrogen-induced damage on the back side of the substrate or device is likewise annihilated. Also taught is an alternate process comprising thermal treatment after hydrogenation of the substrate or device at a temperature of from about 500.degree. C. to about 700.degree. C. for a time period sufficient to cause the impurities to diffuse to the damaged back side thereof for subsequent capture by an alloying metal.

  15. An integrated semiconductor device enabling non-optical genome sequencing.

    Science.gov (United States)

    Rothberg, Jonathan M; Hinz, Wolfgang; Rearick, Todd M; Schultz, Jonathan; Mileski, William; Davey, Mel; Leamon, John H; Johnson, Kim; Milgrew, Mark J; Edwards, Matthew; Hoon, Jeremy; Simons, Jan F; Marran, David; Myers, Jason W; Davidson, John F; Branting, Annika; Nobile, John R; Puc, Bernard P; Light, David; Clark, Travis A; Huber, Martin; Branciforte, Jeffrey T; Stoner, Isaac B; Cawley, Simon E; Lyons, Michael; Fu, Yutao; Homer, Nils; Sedova, Marina; Miao, Xin; Reed, Brian; Sabina, Jeffrey; Feierstein, Erika; Schorn, Michelle; Alanjary, Mohammad; Dimalanta, Eileen; Dressman, Devin; Kasinskas, Rachel; Sokolsky, Tanya; Fidanza, Jacqueline A; Namsaraev, Eugeni; McKernan, Kevin J; Williams, Alan; Roth, G Thomas; Bustillo, James

    2011-07-20

    The seminal importance of DNA sequencing to the life sciences, biotechnology and medicine has driven the search for more scalable and lower-cost solutions. Here we describe a DNA sequencing technology in which scalable, low-cost semiconductor manufacturing techniques are used to make an integrated circuit able to directly perform non-optical DNA sequencing of genomes. Sequence data are obtained by directly sensing the ions produced by template-directed DNA polymerase synthesis using all-natural nucleotides on this massively parallel semiconductor-sensing device or ion chip. The ion chip contains ion-sensitive, field-effect transistor-based sensors in perfect register with 1.2 million wells, which provide confinement and allow parallel, simultaneous detection of independent sequencing reactions. Use of the most widely used technology for constructing integrated circuits, the complementary metal-oxide semiconductor (CMOS) process, allows for low-cost, large-scale production and scaling of the device to higher densities and larger array sizes. We show the performance of the system by sequencing three bacterial genomes, its robustness and scalability by producing ion chips with up to 10 times as many sensors and sequencing a human genome.

  16. Amphoteric oxide semiconductors for energy conversion devices: a tutorial review.

    Science.gov (United States)

    Singh, Kalpana; Nowotny, Janusz; Thangadurai, Venkataraman

    2013-03-07

    In this tutorial review, we discuss the defect chemistry of selected amphoteric oxide semiconductors in conjunction with their significant impact on the development of renewable and sustainable solid state energy conversion devices. The effect of electronic defect disorders in semiconductors appears to control the overall performance of several solid-state ionic devices that include oxide ion conducting solid oxide fuel cells (O-SOFCs), proton conducting solid oxide fuel cells (H-SOFCs), batteries, solar cells, and chemical (gas) sensors. Thus, the present study aims to assess the advances made in typical n- and p-type metal oxide semiconductors with respect to their use in ionic devices. The present paper briefly outlines the key challenges in the development of n- and p-type materials for various applications and also tries to present the state-of-the-art of defect disorders in technologically related semiconductors such as TiO(2), and perovskite-like and fluorite-type structure metal oxides.

  17. Chemical sensors for nuclear industry

    International Nuclear Information System (INIS)

    Gnanasekaran, K.I.

    2012-01-01

    Development of chemical sensors for detection of gases at trace levels for applications in nuclear industry will be highlighted. The sensors have to be highly sensitive, reliable and rugged with long term stability to operate in harsh industrial environment. Semiconductor and solid electrolyte based electrochemical sensors satisfy the requirements. Physico-chemical aspects underlying the development of H 2 sensors in sodium and in cover gas circuit of the Fast breeder reactors for its smooth functioning, NH 3 and H 2 S sensors for use in Heavy water production industries and NO x sensors for spent fuel reprocessing plants will be presented. Development of oxygen sensors to monitor the oxygen level in the reactor containments and sodium sensors for detection of sodium leakages will also be discussed. The talk will focus the general aspects of identification of the sensing material for the respective analyte species, development of suitable chemical route for preparing them as fine powders, the need for configuring them in thick film or thin film geometries and their performance. Pulsed laser deposition method, an elegant technique to prepare the high quality thin films of multicomponent oxides is demonstrated for preparation of nanostructured thin films of complex oxides and its use in tailoring the morphology of the complex sensing material in the desired form by optimizing the in-situ growth conditions. (author)

  18. Semiconductor scintillator detector for gamma radiation

    International Nuclear Information System (INIS)

    Laan, F.T.V. der; Borges, V.; Zabadal, J.R.S.

    2015-01-01

    Nowadays the devices employed to evaluate individual radiation exposition are based on dosimetric films and thermoluminescent crystals, whose measurements must be processed in specific transductors. Hence, these devices carry out indirect measurements. Although a new generation of detectors based on semiconductors which are employed in EPD's (Electronic Personal Dosemeters) being yet available, it high producing costs and large dimensions prevents the application in personal dosimetry. Recent research works reports the development of new detection devices based on photovoltaic PIN diodes, which were successfully employed for detecting and monitoring exposition to X rays. In this work, we step forward by coupling a 2mm anthracene scintillator NE1, which converts the high energy radiation in visible light, generating a Strong signal which allows dispensing the use of photomultipliers. A low gain high performance amplifier and a digital acquisition device are employed to measure instantaneous and cumulative doses for energies ranging from X rays to Gamma radiation up to 2 MeV. One of the most important features of the PIN diode relies in the fact that it can be employed as a detector for ionization radiation, since it requires a small energy amount for releasing electrons. Since the photodiode does not amplify the corresponding photon current, it must be coupled to a low gain amplifier. Therefore, the new sensor works as a scintillator coupled with a photodiode PIN. Preliminary experiments are being performed with this sensor, showing good results for a wide range of energy spectrum. (author)

  19. Fault tolerant control for steam generators in nuclear power plant

    International Nuclear Information System (INIS)

    Deng Zhihong; Shi Xiaocheng; Xia Guoqing; Fu Mingyu

    2010-01-01

    Based on the nonlinear system with stochastic noise, a bank of extended Kalman filters is used to estimate the state of sensors. It can real-time detect and isolate the single sensor fault, and reconstruct the sensor output to keep steam generator water level stable. The simulation results show that the methodology of employing a bank of extended Kalman filters for steam generator fault tolerant control design is feasible. (authors)

  20. What's A Pixel Particle Sensor Chip?

    CERN Multimedia

    2008-01-01

    ATLAS particle physics experiment aided with collaboration ON Semiconductor was recently honored by the European Council for Nuclear Research (CERN), with an Industrial Award recognizing the company's contribution in supplying complex "Pixel Particle Sensor" chips for use in CERN's ATLAS particle physics experiment.

  1. JPL CMOS Active Pixel Sensor Technology

    Science.gov (United States)

    Fossum, E. R.

    1995-01-01

    This paper will present the JPL-developed complementary metal- oxide-semiconductor (CMOS) active pixel sensor (APS) technology. The CMOS APS has achieved performance comparable to charge coupled devices, yet features ultra low power operation, random access readout, on-chip timing and control, and on-chip analog to digital conversion. Previously published open literature will be reviewed.

  2. MIS-based sensors with hydrogen selectivity

    Energy Technology Data Exchange (ETDEWEB)

    Li,; Dongmei, [Boulder, CO; Medlin, J William [Boulder, CO; McDaniel, Anthony H [Livermore, CA; Bastasz, Robert J [Livermore, CA

    2008-03-11

    The invention provides hydrogen selective metal-insulator-semiconductor sensors which include a layer of hydrogen selective material. The hydrogen selective material can be polyimide layer having a thickness between 200 and 800 nm. Suitable polyimide materials include reaction products of benzophenone tetracarboxylic dianhydride 4,4-oxydianiline m-phenylene diamine and other structurally similar materials.

  3. Optimum noise figure and data rate for energy efficient wireless sensor network transceivers

    NARCIS (Netherlands)

    Dutta, R.; van der Zee, Ronan A.R.; Bentum, Marinus Jan; Kokkeler, Andre B.J.

    2011-01-01

    Most applications of wireless sensor networks desire an ultra-low power radio to extend the battery life of a sensor node. With power reducation of processors and semiconductor memories due to advanced CMOS scaling, radio transceiver in the bottleneck to extend battery lifetime of sensor nodes.

  4. CMOS Active-Pixel Image Sensor With Intensity-Driven Readout

    Science.gov (United States)

    Langenbacher, Harry T.; Fossum, Eric R.; Kemeny, Sabrina

    1996-01-01

    Proposed complementary metal oxide/semiconductor (CMOS) integrated-circuit image sensor automatically provides readouts from pixels in order of decreasing illumination intensity. Sensor operated in integration mode. Particularly useful in number of image-sensing tasks, including diffractive laser range-finding, three-dimensional imaging, event-driven readout of sparse sensor arrays, and star tracking.

  5. Semiconductor lasers stability, instability and chaos

    CERN Document Server

    Ohtsubo, Junji

    2017-01-01

    This book describes the fascinating recent advances made concerning the chaos, stability and instability of semiconductor lasers, and discusses their applications and future prospects in detail. It emphasizes the dynamics in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Applications of semiconductor laser chaos, control and noise, and semiconductor lasers are also demonstrated. Semiconductor lasers with new structures, such as vertical-cavity surface-emitting lasers and broad-area semiconductor lasers, are intriguing and promising devices. Current topics include fast physical number generation using chaotic semiconductor lasers for secure communication, development of chaos, quantum-dot semiconductor lasers and quantum-cascade semiconductor lasers, and vertical-cavity surface-emitting lasers. This fourth edition has been significantly expanded to reflect the latest developments. The fundamental theory of laser chaos and the chaotic dynamics in se...

  6. SPICE analysis of the charge division in resistive semiconductor nanowire diodes

    International Nuclear Information System (INIS)

    Guardiola, C; Money, K; Carabe, A

    2014-01-01

    In this paper we present an analysis of the charge division method in semiconductor nanowire Schottky diodes using an electrical model based on the SPICE simulation code. A semiconductor nanowire prototype that is simulated as an RC network and two readout electronic systems are modelled in order to understand its behaviour and to assess its application as a possible ionizing particle detector in clinical high-LET particle beams. We study the use of resistive charge division along the semiconductor nanowire to calculate the position of deposited charge generated by an ionizing particle as it crosses the nanodevice and to determine the minimal viable spatial resolution. Our aim is to demonstrate the charge division concept in resistive semiconductor nanowire diodes, and to subsequently understand the performance of these nanodevices as radiation sensors and address the design limitations of such an application

  7. Exploring graphene field effect transistor devices to improve spectral resolution of semiconductor radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Harrison, Richard Karl [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Howell, Stephen Wayne [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Martin, Jeffrey B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hamilton, Allister B. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2013-12-01

    Graphene, a planar, atomically thin form of carbon, has unique electrical and material properties that could enable new high performance semiconductor devices. Graphene could be of specific interest in the development of room-temperature, high-resolution semiconductor radiation spectrometers. Incorporating graphene into a field-effect transistor architecture could provide an extremely high sensitivity readout mechanism for sensing charge carriers in a semiconductor detector, thus enabling the fabrication of a sensitive radiation sensor. In addition, the field effect transistor architecture allows us to sense only a single charge carrier type, such as electrons. This is an advantage for room-temperature semiconductor radiation detectors, which often suffer from significant hole trapping. Here we report on initial efforts towards device fabrication and proof-of-concept testing. This work investigates the use of graphene transferred onto silicon and silicon carbide, and the response of these fabricated graphene field effect transistor devices to stimuli such as light and alpha radiation.

  8. Semiconductor type n for applications in gas sensing film

    International Nuclear Information System (INIS)

    Cerón Hurtado, Nathalie Marcela; Rodríguez Páez, Jorge Enrique

    2008-01-01

    Semiconductors are materials commonly used in the conformation of the active material in gas sensors, in this paper the synthesis routes are shown for obtaining raw material Sn02-Ti02 system, n-type semiconductor material, methods of characterization the same and the formation of thick films. The synthesis was performed using the methods of precipitation Controlled Polymeric Precursor, characterization of ceramic powders are made using techniques of differential thermal analysis and thermogravimetric (DTA / TG), X-ray diffraction (XRD), Transmission Electron Microscopy (TEM ) and Scanning Electron Microscopy (SEM); Finally they settled in thick films by screen printing method and microstructurally characterized by Optical Microscopy (M0) and Scanning Electron Microscopy (SEM), besides this electrically characterized. The ceramic powders obtained are nanoscale high chemical purity and respond favorably formed films in the presence of oxygen and carbon monoxide.

  9. Simulation and Performance Test Technology Development for Semiconductor Radiation Detection Instrument Fabrication

    International Nuclear Information System (INIS)

    Kim, Jong Kyung; Lee, W. G.; Kim, S. Y.; Shin, C. H.; Kim, K. O.; Park, J. M.; Jang, D. Y.; Kang, J. S.

    2010-06-01

    - Analysis on the Absorbed Dose and Electron Generation by Using MCNPX Code - Analysis on the Change of Measured Energy Spectrum As a Function of Bias Voltage Applied in Semiconductor Detector - Comparison of Monte Carlo Simulation Considering the Charge Collection Efficiency and Experimental Result - Development of Semiconductor Sensor Design Code Based on the Graphic User Interface - Analysis on Depth Profile of Ion-implanted Semiconductor Wafer Surface and Naturally Generated SiO2 Insulation Layer Using Auger Electron Spectroscopy - Measurement of AFM Images and Roughness to Abalyze Surface of Semiconductor Wafer with respect to Annealing and Cleaning Process - Measurement of Physical Properties for Semiconductor Detector Surface after CZT Passivation Process - Evaluation of Crystal Structure and Specific Resistance of CZT - Measurement/Analysis on Band Structure of CZT Crystal - Evaluation of Neutron Convertor Layer with respect to Change in Temperature - Measurement/Evaluation of physical characteristics for lattice parameter, specific resistance, and band structure of CZT crystal - Measurement/Evaluation of lattice transition of SiC semiconductor detector after radiation irradiation - Measurement/Evaluation of performance of semiconductor detector with respect to exposure in high temperature environment

  10. Ambient Sensors

    NARCIS (Netherlands)

    Börner, Dirk; Specht, Marcus

    2014-01-01

    This software sketches comprise two custom-built ambient sensors, i.e. a noise and a movement sensor. Both sensors measure an ambient value and process the values to a color gradient (green > yellow > red). The sensors were built using the Processing 1.5.1 development environment. Available under

  11. Mechanoluminescent Contact Type Sensor

    Directory of Open Access Journals (Sweden)

    A. K. Yefremov

    2017-01-01

    Full Text Available Mechanoluminescent sensing elements convert mechanical stress into optical radiation. Advantages of such sensors are the ability to generate an optical signal, solid-state, simple structure, and resistance to electromagnetic interference. Mechanoluminescent sensor implementations can possess the concentrated and distributed sensitivity, thereby allowing us to detect the field of mechanical stresses distributed across the area and in volume. Most modern semiconductor photo-detectors can detect mechanoluminescent radiation, so there are no difficulties to provide its detection when designing the mechanoluminescent sensing devices. Mechanoluminescent substances have especial sensitivity to shock loads, and this effect can be used to create a fuse the structure of which includes a target contact type sensor with a photosensitive actuator. The paper briefly describes the theoretical basics of mechanoluminiscence: a light signal emerges from the interaction of crystalline phosphor luminescence centers with electrically charged dislocations, moving due to the deformation of the crystal. A mathematical model of the mechanoluminescent conversion is represented as a functional interaction between parameters of the mechanical shock excitation and the sensor light emission. Examples of computing the optical mechanoluminescent output signal depending on the duration and peak level of impulse load are given. It is shown that the luminous flux, generated by mechanoluminescent sensing element when there is an ammunition-target collision causes the current emerging in photo-detector (photodiode that is sufficient for a typical actuator of the fuse train to operate. The potential possibility to create a contact target type sensor based on the light-sensitive mechanoluminescent sensor was proved by the calculation and simulation results.

  12. Semiconductor optoelectronic infrared spectroscopy

    International Nuclear Information System (INIS)

    Hollingworth, A.R.

    2001-08-01

    We use spectroscopy to study infrared optoelectronic inter and intraband semiconductor carrier dynamics. The overall aim of this thesis was to study both III-V and Pb chalcogenide material systems in order to show their future potential use in infrared emitters. The effects of bandstructure engineering have been studied in the output characteristics of mid-IR III-V laser diodes to show which processes (defects, radiative, Auger and phonon) dominate and whether non-radiative processes can be suppressed. A new three-beam pump probe experiment was used to investigate interband recombination directly in passive materials. Experiments on PbSe and theory for non-parabolic near-mirror bands and non-degenerate statistics were in good agreement. Comparisons with HgCdTe showed a reduction in the Auger coefficient of 1-2 orders of magnitude in the PbSe. Using Landau confinement to model spatial confinement in quantum dots (QDs) 'phonon bottlenecking' was studied. The results obtained from pump probe and cyclotron resonance saturation measurements showed a clear suppression in the cooling of carriers when Landau level separation was not resonant with LO phonon energy. When a bulk laser diode was placed in a magnetic field to produce a quasi quantum wire device the resulting enhanced differential gain and reduced Auger recombination lowered I th by 30%. This result showed many peaks in the light output which occurred when the LO phonon energy was a multiple of the Landau level separation. This showed for the first time evidence of the phonon bottleneck in a working laser device. A new technique called time resolved optically detected cyclotron resonance, was used as a precursor to finding the carrier dynamics within a spatially confined quantum dot. By moving to the case of a spatial QD using an optically detected intraband resonance it was possible to measure the energy separation interband levels and conduction and valence sublevels within the dot simultaneously. Furthermore

  13. 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

  14. Submillimeter Spectroscopic Study of Semiconductor Processing Plasmas

    Science.gov (United States)

    Helal, Yaser H.

    Plasmas used for manufacturing processes of semiconductor devices are complex and challenging to characterize. The development and improvement of plasma processes and models rely on feedback from experimental measurements. Current diagnostic methods are not capable of measuring absolute densities of plasma species with high resolution without altering the plasma, or without input from other measurements. At pressures below 100 mTorr, spectroscopic measurements of rotational transitions in the submillimeter/terahertz (SMM) spectral region are narrow enough in relation to the sparsity of spectral lines that absolute specificity of measurement is possible. The frequency resolution of SMM sources is such that spectral absorption features can be fully resolved. Processing plasmas are a similar pressure and temperature to the environment used to study astrophysical species in the SMM spectral region. Many of the molecular neutrals, radicals, and ions present in processing plasmas have been studied in the laboratory and their absorption spectra have been cataloged or are in the literature for the purpose of astrophysical study. Recent developments in SMM devices have made its technology commercially available for applications outside of specialized laboratories. The methods developed over several decades in the SMM spectral region for these laboratory studies are directly applicable for diagnostic measurements in the semiconductor manufacturing industry. In this work, a continuous wave, intensity calibrated SMM absorption spectrometer was developed as a remote sensor of gas and plasma species. A major advantage of intensity calibrated rotational absorption spectroscopy is its ability to determine absolute concentrations and temperatures of plasma species from first principles without altering the plasma environment. An important part of this work was the design of the optical components which couple 500 - 750 GHz radiation through a commercial inductively coupled plasma

  15. Fault tolerant architecture for artificial olfactory system

    International Nuclear Information System (INIS)

    Lotfivand, Nasser; Hamidon, Mohd Nizar; Abdolzadeh, Vida

    2015-01-01

    In this paper, to cover and mask the faults that occur in the sensing unit of an artificial olfactory system, a novel architecture is offered. The proposed architecture is able to tolerate failures in the sensors of the array and the faults that occur are masked. The proposed architecture for extracting the correct results from the output of the sensors can provide the quality of service for generated data from the sensor array. The results of various evaluations and analysis proved that the proposed architecture has acceptable performance in comparison with the classic form of the sensor array in gas identification. According to the results, achieving a high odor discrimination based on the suggested architecture is possible. (paper)

  16. High pressure semiconductor physics I

    CERN Document Server

    Willardson, R K; Paul, William; Suski, Tadeusz

    1998-01-01

    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 indeed that this tra...

  17. Introduction to cathodoluminescence in semiconductors

    International Nuclear Information System (INIS)

    Dussac, M.

    1985-01-01

    The use of cathodoluminescence in a scanning electron microscope leads to acquire a spectrum in a place of the sample surface, or to register the intensity profile of a special emission band along a scanning line, or also to realize a map of the irradiated sample. Composition variations can then, at ambient temperature, be determined, also defects can be shown, together with grain joints and dislocations, radiative and non radiative regions can be distinguished and, at low temperature, elementary processes of luminescence can be studied and impurities identified in semiconductors. Through this analysis method is applicable to every insulating or semiconductor material (that is to say to every material having a gap), in this article only crystalline semi-conductor will be studied [fr

  18. Catalysts, Protection Layers, and Semiconductors

    DEFF Research Database (Denmark)

    Chorkendorff, Ib

    2015-01-01

    Hydrogen is the simplest solar fuel to produce and in this presentation we shall give a short overview of the pros and cons of various tandem devices [1]. The large band gap semiconductor needs to be in front, but apart from that we can chose to have either the anode in front or back using either...... acid or alkaline conditions. Since most relevant semiconductors are very prone to corrosion the advantage of using buried junctions and using protection layers offering shall be discussed [2-4]. Next we shall discuss the availability of various catalysts for being coupled to these protections layers...... and how their stability may be evaluated [5, 6]. Examples of half-cell reaction using protection layers for both cathode and anode will be discussed though some of recent examples under both alkaline and acidic conditions. Si is a very good low band gap semiconductor and by using TiO2 as a protection...

  19. 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

  20. Thiophene-Based Organic Semiconductors.

    Science.gov (United States)

    Turkoglu, Gulsen; Cinar, M Emin; Ozturk, Turan

    2017-10-24

    Thiophene-based π-conjugated organic small molecules and polymers are the research subject of significant current interest owing to their potential use as organic semiconductors in material chemistry. Despite simple and similar molecular structures, the hitherto reported properties of thiophene-based organic semiconductors are rather diverse. Design of high performance organic semiconducting materials requires a thorough understanding of inter- and intra-molecular interactions, solid-state packing, and the influence of both factors on the charge carrier transport. In this chapter, thiophene-based organic semiconductors, which are classified in terms of their chemical structures and their structure-property relationships, are addressed for the potential applications as organic photovoltaics (OPVs), organic field-effect transistors (OFETs) and organic light emitting diodes (OLEDs).

  1. Amorphous Semiconductors: From Photocatalyst to Computer Memory

    Science.gov (United States)

    Sundararajan, Mayur

    Amorphous semiconductors are useful in many applications like solar cells, thin film displays, sensors, electrophotography, etc. The dissertation contains four projects. In the first three projects, semiconductor glasses which are a subset of amorphous semiconductors were studied. The last project is about exploring the strengths and constraints of two analysis programs which calculate the particle size information from experimental Small Angle X-ray Scattering data. By definition, glasses have a random atomic arrangement with no order beyond the nearest neighbor, but strangely there exists an Intermediate Range Order (IRO). The origin of IRO is still not clearly understood, but various models have been proposed. The signature of IRO is the First Sharp Diffraction Peak(FSDP) observed in x-ray and neutron scattering data. The FSDP of TiO 2 SiO2 glass photocatalyst with different Ti:Si ratio from SAXS data was measured to test the theoretical models. The experimental results along with its computer simulation results strongly supported one of two leading models. It was also found that the effect of doping IRO on TiO2 SiO2 is severe in mesoporous form than the bulk form. Glass semiconductors in mesoporous form are very useful photocatalysts due to their large specific surface area. Solar energy conversion of photocatalysts greatly depends on their bandgap, but very few photocatalysts have the optical bandgap covering the whole visible region of solar spectrum leading to poor efficiency. A physical method was developed to manipulate the bandgap of mesoporous photocatalysts, by using the anisotropic thermal expansion and stressed glass network properties of mesoporous glasses. The anisotropic thermal expansion was established by S/WAXS characterization of mesoporous silica (MCM-41). The residual stress in the glass network of mesoporous glasses was already known for an earlier work. The new method was initially applied on mesoporous TiPO4, and the results were

  2. Teaching Tolerance? Associational Diversity and Tolerance Formation

    DEFF Research Database (Denmark)

    Rapp, Carolin; Freitag, Markus

    2015-01-01

    , a closer look is taken at how associational diversity relates to the formation of tolerance and the importance of associations as schools of tolerance are evaluated. The main theoretical argument follows contact theory, wherein regular and enduring contact in diverse settings reduces prejudice and thereby...

  3. Metal oxide gas sensors on the nanoscale

    Science.gov (United States)

    Plecenik, A.; Haidry, A. A.; Plecenik, T.; Durina, P.; Truchly, M.; Mosko, M.; Grancic, B.; Gregor, M.; Roch, T.; Satrapinskyy, L.; Moskova, A.; Mikula, M.; Kus, P.

    2014-06-01

    Low cost, low power and highly sensitive gas sensors operating at room temperature are very important devices for controlled hydrogen gas production and storage. One of the disadvantages of chemosensors is their high operating temperature (usually 200 - 400 °C), which excludes such type of sensors from usage in explosive environment. In this report, a new concept of gas chemosensors operating at room temperature based on TiO2 thin films is discussed. Integration of such sensor is fully compatible with sub-100 nm semiconductor technology and could be transferred directly from labor to commercial sphere.

  4. Semiconductors and semimetals epitaxial microstructures

    CERN Document Server

    Willardson, Robert K; Beer, Albert C; Gossard, Arthur C

    1994-01-01

    Newly developed semiconductor microstructures can now guide light and electrons resulting in important consequences for state-of-the-art electronic and photonic devices. This volume introduces a new generation of epitaxial microstructures. Special emphasis has been given to atomic control during growth and the interrelationship between the atomic arrangements and the properties of the structures.Key Features* Atomic-level control of semiconductor microstructures* Molecular beam epitaxy, metal-organic chemical vapor deposition* Quantum wells and quantum wires* Lasers, photon(IR)detectors, heterostructure transistors

  5. Introduction to semiconductor manufacturing technology

    CERN Document Server

    2012-01-01

    IC chip manufacturing processes, such as photolithography, etch, CVD, PVD, CMP, ion implantation, RTP, inspection, and metrology, are complex methods that draw upon many disciplines. [i]Introduction to Semiconductor Manufacturing Technologies, Second Edition[/i] thoroughly describes the complicated processes with minimal mathematics, chemistry, and physics; it covers advanced concepts while keeping the contents accessible to readers without advanced degrees. Designed as a textbook for college students, this book provides a realistic picture of the semiconductor industry and an in-depth discuss

  6. Wide gap semiconductor microwave devices

    International Nuclear Information System (INIS)

    Buniatyan, V V; Aroutiounian, V M

    2007-01-01

    A review of properties of wide gap semiconductor materials such as diamond, diamond-like carbon films, SiC, GaP, GaN and AlGaN/GaN that are relevant to electronic, optoelectronic and microwave applications is presented. We discuss the latest situation and perspectives based on experimental and theoretical results obtained for wide gap semiconductor devices. Parameters are taken from the literature and from some of our theoretical works. The correspondence between theoretical results and parameters of devices is critically analysed. (review article)

  7. Detection of radioactivity by semiconductors

    International Nuclear Information System (INIS)

    Anon.

    1991-01-01

    The class of detectors discussed in this chapter has a responsive component involving a diode, a junction between two types of semiconductor materials. Although diode detectors are not particularly efficient in counting radioactive emissions, they are superior to other commercially available detectors in spectroscopy. Consequently, diode detectors are used extensively for quanlitative purposes and for quantitative purposes when mixtures of radionuclides are present, not the usual situation with biological or medical research. Topics addressed in this chapter are as follows: Band Theory; Semiconductors and Junctions; and Radiation Detectors. 6 refs., 14 figs

  8. Modeling of semiconductor optical amplifiers

    DEFF Research Database (Denmark)

    Mørk, Jesper; Bischoff, Svend; Berg, Tommy Winther

    We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed.......We discuss the modelling of semiconductor optical amplifiers with emphasis on their high-speed properties. Applications in linear amplification as well as ultrafast optical signal processing are reviewed. Finally, the possible role of quantum-dot based optical amplifiers is discussed....

  9. Semiconductor X-ray spectrometers

    International Nuclear Information System (INIS)

    Muggleton, A.H.F.

    1978-02-01

    An outline is given of recent developments in particle and photon induced x-ray fluorescence (XRF) analysis. Following a brief description of the basic mechanism of semiconductor detector operation a comparison is made between semiconductor detectors, scintillators and gas filled proportional devices. Detector fabrication and cryostat design are described in more detail and the effects of various device parameters on system performance, such as energy resolution, count rate capability, efficiency, microphony, etc. are discussed. The main applications of these detectors in x-ray fluorescence analysis, electron microprobe analysis, medical and pollution studies are reviewed

  10. 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)

  11. 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)

  12. Semiconductor lasers and herterojunction leds

    CERN Document Server

    Kressel, Henry

    2012-01-01

    Semiconductor Lasers and Heterojunction LEDs presents an introduction to the subject of semiconductor lasers and heterojunction LEDs. The book reviews relevant basic solid-state and electromagnetic principles; the relevant concepts in solid state physics; and the p-n junctions and heterojunctions. The text also describes stimulated emission and gain; the relevant concepts in electromagnetic field theory; and the modes in laser structures. The relation between electrical and optical properties of laser diodes; epitaxial technology; binary III-V compounds; and diode fabrication are also consider

  13. A Tactile Sensor Network System Using a Multiple Sensor Platform with a Dedicated CMOS-LSI for Robot Applications.

    Science.gov (United States)

    Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki; Bartley, Travis; Nonomura, Yutaka; Muroyama, Masanori

    2017-08-28

    Robot tactile sensation can enhance human-robot communication in terms of safety, reliability and accuracy. The final goal of our project is to widely cover a robot body with a large number of tactile sensors, which has significant advantages such as accurate object recognition, high sensitivity and high redundancy. In this study, we developed a multi-sensor system with dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) circuit chips (referred to as "sensor platform LSI") as a framework of a serial bus-based tactile sensor network system. The sensor platform LSI supports three types of sensors: an on-chip temperature sensor, off-chip capacitive and resistive tactile sensors, and communicates with a relay node via a bus line. The multi-sensor system was first constructed on a printed circuit board to evaluate basic functions of the sensor platform LSI, such as capacitance-to-digital and resistance-to-digital conversion. Then, two kinds of external sensors, nine sensors in total, were connected to two sensor platform LSIs, and temperature, capacitive and resistive sensing data were acquired simultaneously. Moreover, we fabricated flexible printed circuit cables to demonstrate the multi-sensor system with 15 sensor platform LSIs operating simultaneously, which showed a more realistic implementation in robots. In conclusion, the multi-sensor system with up to 15 sensor platform LSIs on a bus line supporting temperature, capacitive and resistive sensing was successfully demonstrated.

  14. A Tactile Sensor Network System Using a Multiple Sensor Platform with a Dedicated CMOS-LSI for Robot Applications †

    Science.gov (United States)

    Shao, Chenzhong; Tanaka, Shuji; Nakayama, Takahiro; Hata, Yoshiyuki; Bartley, Travis; Muroyama, Masanori

    2017-01-01

    Robot tactile sensation can enhance human–robot communication in terms of safety, reliability and accuracy. The final goal of our project is to widely cover a robot body with a large number of tactile sensors, which has significant advantages such as accurate object recognition, high sensitivity and high redundancy. In this study, we developed a multi-sensor system with dedicated Complementary Metal-Oxide-Semiconductor (CMOS) Large-Scale Integration (LSI) circuit chips (referred to as “sensor platform LSI”) as a framework of a serial bus-based tactile sensor network system. The sensor platform LSI supports three types of sensors: an on-chip temperature sensor, off-chip capacitive and resistive tactile sensors, and communicates with a relay node via a bus line. The multi-sensor system was first constructed on a printed circuit board to evaluate basic functions of the sensor platform LSI, such as capacitance-to-digital and resistance-to-digital conversion. Then, two kinds of external sensors, nine sensors in total, were connected to two sensor platform LSIs, and temperature, capacitive and resistive sensing data were acquired simultaneously. Moreover, we fabricated flexible printed circuit cables to demonstrate the multi-sensor system with 15 sensor platform LSIs operating simultaneously, which showed a more realistic implementation in robots. In conclusion, the multi-sensor system with up to 15 sensor platform LSIs on a bus line supporting temperature, capacitive and resistive sensing was successfully demonstrated. PMID:29061954

  15. Waveguide based external cavity semiconductor lasers

    NARCIS (Netherlands)

    Oldenbeuving, Ruud; Klein, E.J.; Offerhaus, Herman L.; Lee, Christopher James; Verhaegen, M.; Boller, Klaus J.

    2012-01-01

    We report on progress of the project waveguide based external cavity semiconductor laser (WECSL) arrays. Here we present the latest results on our efforts to mode lock an array of tunable, external cavity semiconductor lasers.

  16. Influence of phonons on semiconductor quantum emission

    Energy Technology Data Exchange (ETDEWEB)

    Feldtmann, Thomas

    2009-07-06

    A microscopic theory of interacting charge carriers, lattice vibrations, and light modes in semiconductor systems is presented. The theory is applied to study quantum dots and phonon-assisted luminescence in bulk semiconductors and heterostructures. (orig.)

  17. Semiconductor structure and recess formation etch technique

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Bin; Sun, Min; Palacios, Tomas Apostol

    2017-02-14

    A semiconductor structure has a first layer that includes a first semiconductor material and a second layer that includes a second semiconductor material. The first semiconductor material is selectively etchable over the second semiconductor material using a first etching process. The first layer is disposed over the second layer. A recess is disposed at least in the first layer. Also described is a method of forming a semiconductor structure that includes a recess. The method includes etching a region in a first layer using a first etching process. The first layer includes a first semiconductor material. The first etching process stops at a second layer beneath the first layer. The second layer includes a second semiconductor material.

  18. Fundamentals of semiconductors physics and materials properties

    CERN Document Server

    Yu, Peter Y

    2005-01-01

    Provides detailed explanations of the electronic, vibrational, transport, and optical properties of semiconductors. This textbook emphasizes understanding the physical properties of Si and similar tetrahedrally coordinated semiconductors and features an extensive collection of tables of material parameters, figures, and problems.

  19. Lactose tolerance tests

    Science.gov (United States)

    Hydrogen breath test for lactose tolerance ... Two common methods include: Lactose tolerance blood test Hydrogen breath test The hydrogen breath test is the preferred method. It measures the amount of hydrogen ...

  20. Nuclear radiation detection by a variband semiconductor

    International Nuclear Information System (INIS)

    Volkov, A.S.

    1981-01-01

    Possibilities of using a variband semiconductor for detecting nuclear radiations are considered. It is shown that the variaband quasielectric field effectively collects charges induced by a nuclear particle only at a small mean free path in the semiconductor (up to 100 μm), the luminescence spectrum of the variband semiconductor when a nuclear particle gets into it, in principle, permits to determine both the energy and mean free path in the semiconductor (even at large mean free paths) [ru

  1. Ultrafast THz Saturable Absorption in Doped Semiconductors

    DEFF Research Database (Denmark)

    Turchinovich, Dmitry; Hoffmann, Matthias C.

    2011-01-01

    We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields.......We demonstrate ultrafast THz saturable absorption in n-doped semiconductors by nonlinear THz time-domain spectroscopy. This effect is caused by the semiconductor conductivity modulation due to electron heating and satellite-valley scattering in strong THz fields....

  2. Laser semiconductor diode integrated with frequency doubler

    International Nuclear Information System (INIS)

    Tighineanu, I.; Dorogan, V.; Suruceanu, G.

    2003-01-01

    The invention relates to the technology of optoelectronic semiconductor devices and may be used in the production of laser semiconductor diodes integrated with optical nonlinear elements. The laser semiconductor diode integrated with frequency doubler includes a semiconductor substrate, a laser structure with waveguide. metal contacts in the waveguide of the laser structure it is formed a nanostructured field so that the nanostructure provides for the fulfillment of the phase synchronism conditions

  3. Diode having trenches in a semiconductor region

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, Tomas Apostol; Lu, Bin; Matioli, Elison de Nazareth

    2016-03-22

    An electrode structure is described in which conductive regions are recessed into a semiconductor region. Trenches may be formed in a semiconductor region, such that conductive regions can be formed in the trenches. The electrode structure may be used in semiconductor devices such as field effect transistors or diodes. Nitride-based power semiconductor devices are described including such an electrode structure, which can reduce leakage current and otherwise improve performance.

  4. Thermal Flow Sensors for Harsh Environments.

    Science.gov (United States)

    Balakrishnan, Vivekananthan; Phan, Hoang-Phuong; Dinh, Toan; Dao, Dzung Viet; Nguyen, Nam-Trung

    2017-09-08

    Flow sensing in hostile environments is of increasing interest for applications in the automotive, aerospace, and chemical and resource industries. There are thermal and non-thermal approaches for high-temperature flow measurement. Compared to their non-thermal counterparts, thermal flow sensors have recently attracted a great deal of interest due to the ease of fabrication, lack of moving parts and higher sensitivity. In recent years, various thermal flow sensors have been developed to operate at temperatures above 500 °C. Microelectronic technologies such as silicon-on-insulator (SOI), and complementary metal-oxide semiconductor (CMOS) have been used to make thermal flow sensors. Thermal sensors with various heating and sensing materials such as metals, semiconductors, polymers and ceramics can be selected according to the targeted working temperature. The performance of these thermal flow sensors is evaluated based on parameters such as thermal response time, flow sensitivity. The data from thermal flow sensors reviewed in this paper indicate that the sensing principle is suitable for the operation under harsh environments. Finally, the paper discusses the packaging of the sensor, which is the most important aspect of any high-temperature sensing application. Other than the conventional wire-bonding, various novel packaging techniques have been developed for high-temperature application.

  5. Thermal Flow Sensors for Harsh Environments

    Directory of Open Access Journals (Sweden)

    Vivekananthan Balakrishnan

    2017-09-01

    Full Text Available Flow sensing in hostile environments is of increasing interest for applications in the automotive, aerospace, and chemical and resource industries. There are thermal and non-thermal approaches for high-temperature flow measurement. Compared to their non-thermal counterparts, thermal flow sensors have recently attracted a great deal of interest due to the ease of fabrication, lack of moving parts and higher sensitivity. In recent years, various thermal flow sensors have been developed to operate at temperatures above 500 °C. Microelectronic technologies such as silicon-on-insulator (SOI, and complementary metal-oxide semiconductor (CMOS have been used to make thermal flow sensors. Thermal sensors with various heating and sensing materials such as metals, semiconductors, polymers and ceramics can be selected according to the targeted working temperature. The performance of these thermal flow sensors is evaluated based on parameters such as thermal response time, flow sensitivity. The data from thermal flow sensors reviewed in this paper indicate that the sensing principle is suitable for the operation under harsh environments. Finally, the paper discusses the packaging of the sensor, which is the most important aspect of any high-temperature sensing application. Other than the conventional wire-bonding, various novel packaging techniques have been developed for high-temperature application.

  6. Automation and Integration in Semiconductor Manufacturing

    OpenAIRE

    Liao, Da-Yin

    2010-01-01

    Semiconductor automation originates from the prevention and avoidance of frauds in daily fab operations. As semiconductor technology and business continuously advance and grow, manufacturing systems must aggressively evolve to meet the changing technical and business requirements in this industry. Semiconductor manufacturing has been suffering pains from islands of automation. The problems associated with these systems are limited

  7. Semiconductor nanostructures for infrared applications

    NARCIS (Netherlands)

    Zurauskiene, N.; Asmontas, S.; Dargys, A.; Kundrotas, J.; Janssen, G.; Goovaerts, E.; Marcinkevicius, S.; Koenraad, P.M.; Wolter, J.H.; Leon, R.

    2004-01-01

    We present the results of time-resolved photoluminescence (TRPL) and optically detected microwave resonance (ODMR) spectroscopy investigations of semiconductor quantum dots and quantum wells. The ODMR spectra of InAs/GaAs QDs were detected via modulation of the total intensity of the QDs emission

  8. A Brief History of ... Semiconductors

    Science.gov (United States)

    Jenkins, Tudor

    2005-01-01

    The development of studies in semiconductor materials is traced from its beginnings with Michael Faraday in 1833 to the production of the first silicon transistor in 1954, which heralded the age of silicon electronics and microelectronics. Prior to the advent of band theory, work was patchy and driven by needs of technology. However, the arrival…

  9. Semiconductor radiation detectors: device physics

    National Research Council Canada - National Science Library

    Lutz, Gerhard

    1999-01-01

    ..., including nuclear physics, elementary particle physics, optical and x-ray astronomy, medicine, and materials testing - and the number of applications is growing continually. Closely related, and initiated by the application of semiconductors, is the development of low-noise low-power integrated electronics for signal readout. The success of semicond...

  10. Towards filament free semiconductor lasers

    DEFF Research Database (Denmark)

    McInerney, John; O'Brien, Peter; Skovgaard, Peter M. W.

    2000-01-01

    We outline physical models and simulations for suppression of self-focusing and filamentation in large aperture semiconductor lasers. The principal technical objective is to generate multi-watt CW or quasi-CW outputs with nearly diffraction limited beams, suitable for long distance free space...... propagation structures in lasers and amplifiers which suppress lateral reflections....

  11. Ultrafast Spectroscopy of Semiconductor Devices

    DEFF Research Database (Denmark)

    Borri, Paola; Langbein, Wolfgang; Hvam, Jørn Marcher

    1999-01-01

    In this work we present an experimental technique for investigating ultrafast carrier dynamics in semiconductor optical amplifiers at room temperature. These dynamics, influenced by carrier heating, spectral hole-burning and two-photon absorption, are very important for device applications in inf...

  12. Radiation damage in semiconductor detectors

    International Nuclear Information System (INIS)

    Kraner, H.W.

    1981-12-01

    A survey is presented of the important damage-producing interactions in semiconductor detectors and estimates of defect numbers are made for MeV protons, neutrons and electrons. Damage effects of fast neutrons in germanium gamma ray spectrometers are given in some detail. General effects in silicon detectors are discussed and damage constants and their relationship to leakage current is introduced

  13. The silicon microstrip sensors of the ATLAS semiconductor tracker

    Czech Academy of Sciences Publication Activity Database

    Ahmad, A.; Albrechtskirchinger, Z.; Allport, P.; Böhm, Jan; Mikeštíková, Marcela; Šťastný, Jan

    2007-01-01

    Roč. 578, - (2007), s. 98-118 ISSN 0168-9002 Institutional research plan: CEZ:AV0Z10100502 Keywords : ATLAS * SCT * silicon * microstrip * module * LHC Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 1.114, year: 2007

  14. New solid-state chemical sensors for monitoring water chemistry at elevated temperatures

    International Nuclear Information System (INIS)

    Sugimoto, Katsuhisa

    1996-01-01

    One of the most important chemical sensors for water chemistry is a pH sensor. Characteristics of two types of common pH sensors for high temperature use, that is, a ZrO 2 membrane type and a TiO 2 semiconductor type, were first reviewed. Then, a new ZrO 2 disk pH sensor was introduced. This new pH sensor covers weak points of the common pH sensors and shows good linear relationships between the potential of the sensor and the solution pH at high temperatures. (author)

  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. Optical and Electronic NOx Sensors for Applications in Mechatronics

    Directory of Open Access Journals (Sweden)

    Scott D. Wolter

    2009-05-01

    Full Text Available Current production and emerging NOx sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i Quantum cascade lasers (QCL based photoacoustic (PA systems; ii gold nanoparticles as catalytically active materials in field-effect transistor (FET sensors, and iii functionalized III-V semiconductor based devices. QCL-based PA sensors for NOx show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NOx in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NOx sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling.

  17. Optical and Electronic NOx Sensors for Applications in Mechatronics

    Science.gov (United States)

    Di Franco, Cinzia; Elia, Angela; Spagnolo, Vincenzo; Scamarcio, Gaetano; Lugarà, Pietro Mario; Ieva, Eliana; Cioffi, Nicola; Torsi, Luisa; Bruno, Giovanni; Losurdo, Maria; Garcia, Michael A.; Wolter, Scott D.; Brown, April; Ricco, Mario

    2009-01-01

    Current production and emerging NOx sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i) Quantum cascade lasers (QCL) based photoacoustic (PA) systems; ii) gold nanoparticles as catalytically active materials in field-effect transistor (FET) sensors, and iii) functionalized III-V semiconductor based devices. QCL-based PA sensors for NOx show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NOx in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NOx sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling. PMID:22412315

  18. Towards a Chemiresistive Sensor-Integrated Electronic Nose: A Review

    Directory of Open Access Journals (Sweden)

    Kea-Tiong Tang

    2013-10-01

    Full Text Available Electronic noses have potential applications in daily life, but are restricted by their bulky size and high price. This review focuses on the use of chemiresistive gas sensors, metal-oxide semiconductor gas sensors and conductive polymer gas sensors in an electronic nose for system integration to reduce size and cost. The review covers the system design considerations and the complementary metal-oxide-semiconductor integrated technology for a chemiresistive gas sensor electronic nose, including the integrated sensor array, its readout interface, and pattern recognition hardware. In addition, the state-of-the-art technology integrated in the electronic nose is also presented, such as the sensing front-end chip, electronic nose signal processing chip, and the electronic nose system-on-chip.

  19. Recognition and Toleration

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2010-01-01

    Recognition and toleration are ways of relating to the diversity characteristic of multicultural societies. The article concerns the possible meanings of toleration and recognition, and the conflict that is often claimed to exist between these two approaches to diversity. Different forms...... or interpretations of recognition and toleration are considered, confusing and problematic uses of the terms are noted, and the compatibility of toleration and recognition is discussed. The article argues that there is a range of legitimate and importantly different conceptions of both toleration and recognition...

  20. Fault Tolerant Feedback Control

    DEFF Research Database (Denmark)

    Stoustrup, Jakob; Niemann, H.

    2001-01-01

    An architecture for fault tolerant feedback controllers based on the Youla parameterization is suggested. It is shown that the Youla parameterization will give a residual vector directly in connection with the fault diagnosis part of the fault tolerant feedback controller. It turns out...... that there is a separation be-tween the feedback controller and the fault tolerant part. The closed loop feedback properties are handled by the nominal feedback controller and the fault tolerant part is handled by the design of the Youla parameter. The design of the fault tolerant part will not affect the design...... of the nominal feedback con-troller....

  1. Development of Microfabricated Chemical Gas Sensors and Sensor Arrays for Aerospace Applications

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Fralick, G.; Thomas, V.; Liu, C. C.; Wu, W. H.; Ward, B.; Makel, D.

    2002-01-01

    Aerospace applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. In particular, factors such as minimal sensor size, weight, and power consumption are particularly important. Development areas which have potential aerospace applications include launch vehicle leak detection, engine health monitoring, fire detection, and environmental monitoring. Sensor development for these applications is based on progress in three types of technology: 1) Micromachining and microfabrication (Microsystem) technology to fabricate miniaturized sensors. 2) The use of nanocrystalline materials to develop sensors with improved stability combined with higher sensitivity. 3) The development of high temperature semiconductors, especially silicon carbide. However, due to issues of selectivity and cross-sensitivity, individual sensors are limited in the amount of information that they can provide in environments that contain multiple chemical species. Thus, sensor arrays are being developed to address detection needs in such multi-species environments. This paper discusses the needs of space applications as well as the point-contact sensor technology and sensor arrays being developed to address these needs. Sensors to measure hydrogen, hydrocarbons, hydrazine, nitrogen oxides (NO,), carbon monoxide, oxygen, and carbon dioxide are being developed as well as arrays for leak, fire, and emissions detection. Demonstrations of the technology will also be discussed. It is concluded that microfabricated sensor technology has significant potential for use in a range of aerospace applications.

  2. Attention Sensor

    NARCIS (Netherlands)

    Börner, Dirk; Kalz, Marco; Specht, Marcus

    2014-01-01

    This software sketch was used in the context of an experiment for the PhD project “Ambient Learning Displays”. The sketch comprises a custom-built attention sensor. The sensor measured (during the experiment) whether a participant looked at and thus attended a public display. The sensor was built

  3. A 94GHz Temperature Compensated Low Noise Amplifier in 45nm Silicon-on-Insulator Complementary Metal-Oxide Semiconductor (SOI CMOS)

    Science.gov (United States)

    2014-01-01

    ring oscillator based temperature sensor will be designed to compensate for gain variations over temperature. For comparison to a competing solution...Simulated (Green) Capacitance of the GSG Pads ........................ 9 Figure 6: Die Picture and Schematic of the L-2L Coplanar Waveguides...complementary metal-oxide-semiconductor (CMOS) technology. A ring oscillator based temperature sensor was designed to compensate for gain variations

  4. Currently Commercially Available Chemical Sensors Employed for Detection of Volatile Organic Compounds in Outdoor and Indoor Air

    OpenAIRE

    Bartosz Szulczyński; Jacek Gębicki

    2017-01-01

    The paper presents principle of operation and design of the most popular chemical sensors for measurement of volatile organic compounds (VOCs) in outdoor and indoor air. It describes the sensors for evaluation of explosion risk including pellistors and IR-absorption sensors as well as the sensors for detection of toxic compounds such as electrochemical (amperometric), photoionization and semiconductor with solid electrolyte ones. Commercially available sensors for detection of VOCs and their ...

  5. Fermi level dependent native defect formation: Consequences for metal-semiconductor and semiconductor-semiconductor interfaces

    International Nuclear Information System (INIS)

    Walukiewicz, W.

    1988-02-01

    The amphoteric native defect model of the Schottky barrier formation is used to analyze the Fermi level pinning at metal/semiconductor interfaces for submonolayer metal coverages. It is assumed that the energy required for defect generation is released in the process of surface back-relaxation. Model calculations for metal/GaAs interfaces show a weak dependence of the Fermi level pinning on the thickness of metal deposited at room temperature. This weak dependence indicates a strong dependence of the defect formation energy on the Fermi level, a unique feature of amphoteric native defects. This result is in very good agreement with experimental data. It is shown that a very distinct asymmetry in the Fermi level pinning on p- and n-type GaAs observed at liquid nitrogen temperatures can be understood in terms of much different recombination rates for amphoteric native defects in those two types of materials. Also, it is demonstrated that the Fermi level stabilization energy, a central concept of the amphoteric defect system, plays a fundamental role in other phenomena in semiconductors such as semiconductor/semiconductor heterointerface intermixing and saturation of free carrier concentration. 33 refs., 6 figs

  6. Mechanical tolerance stackup and analysis

    CERN Document Server

    Fischer, Bryan R

    2004-01-01

    BackgroundDimensioning and TolerancingTolerance Format and Decimal PlacesConverting Plus/Minus Dimensions and Tolerances into Equal Bilaterally Toleranced DimensionsVariation and Sources of VariationTolerance AnalysisWorst-case Tolerance StackupsStatistical Tolerance StackupsGeometric Dimensioning and Tolerancing (GD&T)Converting Plus/Minus Tolerancing to Positional Tolerancing and Projected Tolerance ZonesDiametral and Radial Tolerance StackupsSpecifying Material Condition Modifiers and Their Effect on Tolerance Stackups The Tolerance Stackup SketchThe Tolerance Stackup Report FormTolerance S

  7. Chemical Modification of Semiconductor Surfaces for Molecular Electronics.

    Science.gov (United States)

    Vilan, Ayelet; Cahen, David

    2017-03-08

    Inserting molecular monolayers within metal/semiconductor interfaces provides one of the most powerful expressions of how minute chemical modifications can affect electronic devices. This topic also has direct importance for technology as it can help improve the efficiency of a variety of electronic devices such as solar cells, LEDs, sensors, and possible future bioelectronic ones. The review covers the main aspects of using chemistry to control the various aspects of interface electrostatics, such as passivation of interface states and alignment of energy levels by intrinsic molecular polarization, as well as charge rearrangement with the adjacent metal and semiconducting contacts. One of the greatest merits of molecular monolayers is their capability to form excellent thin dielectrics, yielding rich and unique current-voltage characteristics for transport across metal/molecular monolayer/semiconductor interfaces. We explain the interplay between the monolayer as tunneling barrier on the one hand, and the electrostatic barrier within the semiconductor, due to its space-charge region, on the other hand, as well as how different monolayer chemistries control each of these barriers. Practical tools to experimentally identify these two barriers and distinguish between them are given, followed by a short look to the future. This review is accompanied by another one, concerning the formation of large-area molecular junctions and charge transport that is dominated solely by molecules.

  8. Chemical Gas Sensors for Aeronautic and Space Applications 2

    Science.gov (United States)

    Hunter, G. W.; Chen, L. Y.; Neudeck, P. G.; Knight, D.; Liu, C. C.; Wu, Q. H.; Zhou, H. J.; Makel, D.; Liu, M.; Rauch, W. A.

    1998-01-01

    Aeronautic and Space applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. Areas of most interest include launch vehicle safety monitoring emission monitoring and fire detection. This paper discusses the needs of aeronautic and space applications and the point-contact sensor technology being developed to address these needs. The development of these sensor is based on progress two types of technology: 1) Micro-machining and micro-fabrication technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Sensor development for each application involves its own challenges in the fields of materials science and fabrication technology. The number of dual-use commercial applications of this micro-fabricated gas sensor technology make this area of sensor development a field of significant interest.

  9. Chemical Gas Sensors for Aeronautics and Space Applications III

    Science.gov (United States)

    Hunter, G. W.; Neudeck, P. G.; Chen, L. Y.; Liu, C. C.; Wu, Q. H.; Sawayda, M. S.; Jin, Z.; Hammond, J.; Makel, D.; Liu, M.; hide

    1999-01-01

    Aeronautic and space applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. Areas of interest include launch vehicle safety monitoring, emission monitoring, and fire detection. This paper discusses the needs of aeronautic and space applications and the point-contact sensor technology being developed to address these needs. The development of these sensors is based on progress in two types of technology: 1) Micromachining and microfabrication technology to fabricate miniaturized sensors. 2) The development of high temperature semiconductors, especially silicon carbide. Sensor development for each application involves its own challenges in the fields of materials science and fabrication technology. The number of dual-use commercial applications of this microfabricated gas sensor technology make this area of sensor development a field of significant interest.

  10. Digital Inverter Amine Sensing via Synergistic Responses by n and p Organic Semiconductors.

    Science.gov (United States)

    Tremblay, Noah J; Jung, Byung Jun; Breysse, Patrick; Katz, Howard E

    2011-11-22

    Chemiresistors and sensitive OFETs have been substantially developed as cheap, scalable, and versatile sensing platforms. While new materials are expanding OFET sensing capabilities, the device architectures have changed little. Here we report higher order logic circuits utilizing OFETs sensitive to amine vapors. The circuits depend on the synergistic responses of paired p- and n-channel organic semiconductors, including an unprecedented analyte-induced current increase by the n-channel semiconductor. This represents the first step towards 'intelligent sensors' that utilize analog signal changes in sensitive OFETs to produce direct digital readouts suitable for further logic operations.

  11. Mechanisms of Current Transfer in Electrodeposited Layers of Submicron Semiconductor Particles

    Science.gov (United States)

    Zhukov, N. D.; Mosiyash, D. S.; Sinev, I. V.; Khazanov, A. A.; Smirnov, A. V.; Lapshin, I. V.

    2017-12-01

    Current-voltage ( I- V) characteristics of conductance in multigrain layers of submicron particles of silicon, gallium arsenide, indium arsenide, and indium antimonide have been studied. Nanoparticles of all semiconductors were obtained by processing initial single crystals in a ball mill and applied after sedimentation onto substrates by means of electrodeposition. Detailed analysis of the I- V curves of electrodeposited layers shows that their behavior is determined by the mechanism of intergranular tunneling emission from near-surface electron states of submicron particles. Parameters of this emission process have been determined. The proposed multigrain semiconductor structures can be used in gas sensors, optical detectors, IR imagers, etc.

  12. Semiconductor detectors in nuclear and particle physics

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.

    1992-01-01

    Semiconductor detectors for elementary particle physics and nuclear physics in the energy range above 1 GeV are briefly reviewed. In these two fields semiconductor detectors are used mainly for the precise position sensing. In a typical experiment, the position of a fast charged particle crossing a relatively thin semiconductor detector is measured. The position resolution achievable by semiconductor detectors is compared with the resolution achievable by gas filled position sensing detectors. Semiconductor detectors are divided into two groups: Classical semiconductor diode detectors and semiconductor memory detectors. Principles of the signal formation and the signal read-out for both groups of detectors are described. New developments of silicon detectors of both groups are reported

  13. Semiconductor detectors in nuclear and particle physics

    International Nuclear Information System (INIS)

    Rehak, P.; Gatti, E.

    1995-01-01

    Semiconductor detectors for elementary particle physics and nuclear physics in the energy range above 1 GeV are briefly reviewed. In these two fields semiconductor detectors are used mainly for the precise position sensing. In a typical experiment, the position of a fast charged particle crossing a relatively thin semiconductor detector is measured. The position resolution achievable by semiconductor detectors is compared with the resolution achievable by gas filled position sensing detectors. Semiconductor detectors are divided into two groups; (i) classical semiconductor diode detectors and (ii) semiconductor memory detectors. Principles of the signal formation and the signal read-out for both groups of detectors are described. New developments of silicon detectors of both groups are reported. copyright 1995 American Institute of Physics

  14. The ATLAS semiconductor tracker: operations and performance

    CERN Document Server

    D'Auria, S; The ATLAS collaboration

    2012-01-01

    The Semi-Conductor Tracker (SCT) is a silicon strip detector and one of the key precision tracking devices in the Inner Detector of the ATLAS experiment at CERN LHC. The SCT is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar {it p}-in-{it n} technology. The signals are processed in the front-end ASICS ABCD3TA, working in binary readout mode. Data is transferred to the off-detector readout electronics via optical fibres. We find 99.3% of the SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications. In the talk the current results from the successful operation of the SCT Detector at the LHC and its status af...

  15. The ATLAS Semiconductor tracker: operations and performance

    CERN Document Server

    Pani, P; The ATLAS collaboration

    2013-01-01

    Tracker After more than 3 years of successful operation at the LHC, we report on the operation and performance of the Semi-Conductor Tracker (SCT) functioning in a high luminosity, high radiation environment. The SCT is part of the ATLAS experiment at CERN and is constructed of 4088 silicon detector modules for a total of 6.3 million strips. Each module is designed, constructed and tested to operate as a stand-alone unit, mechanically, electrically, optically and thermally. The modules are mounted into two types of structures: one barrel (4 cylinders) and two end-cap systems (9 disks on each end of the barrel). The SCT silicon micro-strip sensors are processed in the planar p-in-n technology. The signals are processed in the front-end ABCD3TA ASICs, which use a binary readout architecture. Data is transferred to the off-detector readout electronics via optical fibers. We find 99.3% of the SCT modules are operational, noise occupancy and hit efficiency exceed the design specifications; the alignment is very cl...

  16. Multianalyte biosensor based on pH-sensitive ZnO electrolyte–insulator–semiconductor structures

    International Nuclear Information System (INIS)

    Haur Kao, Chyuan; Chun Liu, Che; Ueng, Herng-Yih; Chen, Hsiang; Cheng Chu, Yu; Jie Chen, Yu; Ling Lee, Ming; Ming Chang, Kow

    2014-01-01

    Multianalyte electrolyte–insulator–semiconductor (EIS) sensors with a ZnO sensing membrane annealed on silicon substrate for use in pH sensing were fabricated. Material analyses were conducted using X-ray diffraction and atomic force microscopy to identify optimal treatment conditions. Sensing performance for various ions of Na + , K + , urea, and glucose was also tested. Results indicate that an EIS sensor with a ZnO membrane annealed at 600 °C exhibited good performance with high sensitivity and a low drift rate compared with all other reported ZnO-based pH sensors. Furthermore, based on well-established pH sensing properties, pH-ion-sensitive field-effect transistor sensors have also been developed for use in detecting urea and glucose ions. ZnO-based EIS sensors show promise for future industrial biosensing applications

  17. Extraordinary Magnetoresistance Effect in Semiconductor/Metal Hybrid Structure

    KAUST Repository

    Sun, Jian

    2013-06-27

    In this dissertation, the extraordinary magnetoresistance (EMR) effect in semiconductor/metal hybrid structures is studied to improve the performance in sensing applications. Using two-dimensional finite element simulations, the geometric dependence of the output sensitivity, which is a more relevant parameter for EMR sensors than the magnetoresistance (MR), is studied. The results show that the optimal geometry in this case is different from the geometry reported before, where the MR ratio was optimized. A device consisting of a semiconductor bar with length/width ratio of 5~10 and having only 2 contacts is found to exhibit the highest sensitivity. A newly developed three-dimensional finite element model is employed to investigate parameters that have been neglected with the two dimensional simulations utilized so far, i.e., thickness of metal shunt and arbitrary semiconductor/metal interface. The simulations show the influence of those parameters on the sensitivity is up to 10 %. The model also enables exploring the EMR effect in planar magnetic fields. In case of a bar device, the sensitivity to planar fields is about 15 % to 20 % of the one to perpendicular fields. 5 A “top-contacted” structure is proposed to reduce the complexity of fabrication, where neither patterning of the semiconductor nor precise alignment is required. A comparison of the new structure with a conventionally fabricated device shows that a similar magnetic field resolution of 24 nT/√Hz is obtained. A new 3-contact device is developed improving the poor low-field sensitivity observed in conventional EMR devices, resulting from its parabolic magnetoresistance response. The 3-contact device provides a considerable boost of the low field response by combining the Hall effect with the EMR effect, resulting in an increase of the output sensitivity by 5 times at 0.01 T compared to a 2-contact device. The results of this dissertation provide new insights into the optimization of EMR devices

  18. Semiconductor Nonlinear Dynamics Study by Broadband Terahertz Spectroscopy

    Science.gov (United States)

    Ho, I.-Chen

    Semiconductor nonlinearity in the terahertz (THz) frequency range has been attracting considerable attention due to the recent development of high-power semiconductor-based nanodevices. However, the underlying physics concerning carrier dynamics in the presence of high-field THz transients is still obscure. This thesis introduces an ultrafast, time-resolved THz pump/THz probe approach to the study of semiconductor properties in the nonlinear regime. The carrier dynamics regarding two mechanisms, intervalley scattering and impact ionization, is observed for doped InAs on a sub-picosecond time scale. In addition, polaron modulation driven by intense THz pulses is experimentally and theoretically investigated. The observed polaron dynamics verifies the interaction between energetic electrons and a phonon field. In contrast to previous work which reports optical phonon responses, acoustic phonon modulations are addressed in this study. A further understanding of the intense field interacting with solid materials will accelerate the development of semiconductor devices. This thesis starts with the design and performance of a table-top THz spectrometer which has the advantages of ultra-broad bandwidth (one order higher bandwidth compared to a conventional ZnTe sensor) and high electric field strength (>100 kV/cm). Unlike the conventional THz time-domain spectroscopy, the spectrometer integrates a novel THz air-biased-coherent-detection (THz-ABCD) technique and utilizes selected gases as THz emitters and sensors. In comparison with commonly used electro-optic (EO) crystals or photoconductive (PC) dipole antennas, the gases have the benefits of no phonon absorption as existing in EO crystals and no carrier life time limitation as observed in PC dipole antennas. The newly development THz-ABCD spectrometer with a strong THz field strength capability provides a platform for various research topics especially on the nonlinear carrier dynamics of semiconductors. Two mechanisms

  19. The Integration of Bacteriorhodopsin Proteins with Semiconductor Heterostructure Devices

    Science.gov (United States)

    Xu, Jian

    2008-03-01

    Bioelectronics has emerged as one of the most rapidly developing fields among the active frontiers of interdisciplinary research. A major thrust in this field is aimed at the coupling of the technologically-unmatched performance of biological systems, such as neural and sensing functions, with the well developed technology of microelectronics and optoelectronics. To this end we have studied the integration of a suitably engineered protein, bacteriorhodopsin (BR), with semiconductor optoelectronic devices and circuits. Successful integration will potentially lead to ultrasensitive sensors with polarization selectivity and built-in preprocessing capabilities that will be useful for high speed tracking, motion and edge detection, biological detection, and artificial vision systems. In this presentation we will summarize our progresses in this area, which include fundamental studies on the transient dynamics of photo-induced charge shift in BR and the coupling mechanism at protein-semiconductor interface for effective immobilizing and selectively integrating light sensitive proteins with microelectronic devices and circuits, and the device engineering of BR-transistor-integrated optical sensors as well as their applications in phototransceiver circuits. Work done in collaboration with Pallab Bhattacharya, Jonghyun Shin, Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI; Robert R. Birge, Department of Chemistry, University of Connecticut, Storrs, CT 06269; and György V'ar'o, Institute of Biophysics, Biological Research Center of the Hungarian Academy of Science, H-6701 Szeged, Hungary.

  20. Performance Evaluation of Three-Level Z-Source Inverters Under Semiconductor-Failure Conditions

    DEFF Research Database (Denmark)

    Gao, Feng; Loh, Poh Chiang; Blaabjerg, Frede

    2009-01-01

    This paper evaluates and proposes various compensation methods for three-level Z-source inverters under semiconductor-failure conditions. Unlike the fault-tolerant techniques used in traditional three-level inverters, where either an extra phase-leg or collective switching states are used......, the proposed methods for three-level Z-source inverters simply reconfigure their relevant gating signals so as to ride-through the failed semiconductor conditions smoothly without any significant decrease in their ac-output quality and amplitude. These features are partly attributed to the inherent boost...... under semiconductor-failure conditions. For verifying these described performance features, PLECS simulation and experimental testing were performed with some results captured and shown in a later section for visual confirmation....

  1. Transversal light forces in semiconductors

    CERN Document Server

    Lindberg, M

    2003-01-01

    The transversal light force is a well established effect in atomic and molecular systems that are exposed to spatially inhomogeneous light fields. In this paper it is shown theoretically that in an excited semiconductor, containing an electron-hole plasma or excitons, a similar light force exists, if the semiconductor is exposed to an ultrashort spatially inhomogeneous light field. The analysis is based on the equations of motion for the Wigner distribution functions of charge carrier populations and interband polarizations. The results show that, while the light force on the electron-hole plasma or the excitons does exist, its effects on the kinetic behaviour of the electron-hole plasma or the excitons are different compared to the situation in an atomic or molecular system. A detailed analysis presented here traces this difference back to the principal differences between atoms and molecules on the one hand and electron-hole plasmas or excitons on the other hand.

  2. 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.

  3. Hypersonic modes in nanophononic semiconductors.

    Science.gov (United States)

    Hepplestone, S P; Srivastava, G P

    2008-09-05

    Frequency gaps and negative group velocities of hypersonic phonon modes in periodically arranged composite semiconductors are presented. Trends and criteria for phononic gaps are discussed using a variety of atomic-level theoretical approaches. From our calculations, the possibility of achieving semiconductor-based one-dimensional phononic structures is established. We present results of the location and size of gaps, as well as negative group velocities of phonon modes in such structures. In addition to reproducing the results of recent measurements of the locations of the band gaps in the nanosized Si/Si{0.4}Ge{0.6} superlattice, we show that such a system is a true one-dimensional hypersonic phononic crystal.

  4. Dielectric function of semiconductor superlattice

    International Nuclear Information System (INIS)

    Qin Guoyi.

    1990-08-01

    We present a calculation of the dielectric function for semiconductor GaAs/Ga 1-x Al x As superlattice taking account of the extension of the electron envelope function and the difference of both the dielectric constant and width between GaAs and Ga 1-x Al x As layers. In the appropriate limits, our results exactly reduce to the well-known results of the quasi two-dimensional electron gas obtained by Lee and Spector and of the period array of two-dimensional electron layers obtained by Das Sarma and Quinn. By means of the dielectric function of the superlattice, the dispersion relation of the collective excitation and the screening property of semiconductor superlattice are discussed and compared with the results of the quasi two-dimensional system and with the results of the periodic array of the two-dimensional electron layers. (author). 4 refs, 3 figs

  5. Spectroscopic analysis of optoelectronic semiconductors

    CERN Document Server

    Jimenez, Juan

    2016-01-01

    This book deals with standard spectroscopic techniques which can be used to analyze semiconductor samples or devices, in both, bulk, micrometer and submicrometer scale. The book aims helping experimental physicists and engineers to choose the right analytical spectroscopic technique in order to get specific information about their specific demands. For this purpose, the techniques including technical details such as apparatus and probed sample region are described. More important, also the expected outcome from experiments is provided. This involves also the link to theory, that is not subject of this book, and the link to current experimental results in the literature which are presented in a review-like style. Many special spectroscopic techniques are introduced and their relationship to the standard techniques is revealed. Thus the book works also as a type of guide or reference book for people researching in optical spectroscopy of semiconductors.

  6. Efficient Spin Injection into Semiconductor

    International Nuclear Information System (INIS)

    Nahid, M.A.I.

    2010-06-01

    Spintronic research has made tremendous progress nowadays for making future devices obtain extra advantages of low power, and faster and higher scalability compared to present electronic devices. A spintronic device is based on the transport of an electron's spin instead of charge. Efficient spin injection is one of the very important requirements for future spintronic devices. However, the effective spin injection is an exceedingly difficult task. In this paper, the importance of spin injection, basics of spin current and the essential requirements of spin injection are illustrated. The experimental technique of electrical spin injection into semiconductor is also discussed based on the experimental experience. The electrical spin injection can easily be implemented for spin injection into any semiconductor. (author)

  7. 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.

  8. Semiconductors put spin in spintronics

    International Nuclear Information System (INIS)

    Weiss, Dieter

    2000-01-01

    Electrons and holes, which carry the current in semiconductor devices, are quantum-mechanical objects characterized by a set of quantum numbers - the band index, the wave-vector (which is closely related to the electron or hole velocity) and spin. The spin, however, is one of the strangest properties of particles. In simple terms, we can think of the spin as an internal rotation of the electron, but it has no classical counterpart. The spin is connected to a quantized magnetic moment and hence acts as a microscopic magnet. Thus the electron spin can adopt one of two directions (''up'' or ''down'') in a magnetic field. The spin plays no role in conventional electronics and the current in any semiconductor device is made up of a mixture of electrons with randomly oriented spins. However, a new range of electronic devices that transport the spin of the electrons, in addition to their charge, is being developed. But the biggest obstacle to making practical ''spin electronic'' or ''spintronic'' devices so far has been finding a way of injecting spin-polarized electrons or holes into the semiconductor and then detecting them. Recently a team of physicists from the University of Wuerzburg in Germany, and also a collaboration of researchers from Tohoku University in Japan and the University of California at Santa Barbara, have found a way round these problems using either semi-magnetic or ferromagnetic semiconductors as ''spin aligners'' (R Fiederling et al. 1999 Nature 402 787; Y Ohno et al. 1999 Nature 402 790). In this article the author presents the latest breakthrough in spintronics research. (UK)

  9. Dry etching technology for semiconductors

    CERN Document Server

    Nojiri, Kazuo

    2015-01-01

    This book is a must-have reference to dry etching technology for semiconductors, which will enable engineers to develop new etching processes for further miniaturization and integration of semiconductor integrated circuits.  The author describes the device manufacturing flow, and explains in which part of the flow dry etching is actually used. The content is designed as a practical guide for engineers working at chip makers, equipment suppliers and materials suppliers, and university students studying plasma, focusing on the topics they need most, such as detailed etching processes for each material (Si, SiO2, Metal etc) used in semiconductor devices, etching equipment used in manufacturing fabs, explanation of why a particular plasma source and gas chemistry are used for the etching of each material, and how to develop etching processes.  The latest, key technologies are also described, such as 3D IC Etching, Dual Damascene Etching, Low-k Etching, Hi-k/Metal Gate Etching, FinFET Etching, Double Patterning ...

  10. 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

  11. Thienoacene-based organic semiconductors.

    Science.gov (United States)

    Takimiya, Kazuo; Shinamura, Shoji; Osaka, Itaru; Miyazaki, Eigo

    2011-10-11

    Thienoacenes consist of fused thiophene rings in a ladder-type molecular structure and have been intensively studied as potential organic semiconductors for organic field-effect transistors (OFETs) in the last decade. They are reviewed here. Despite their simple and similar molecular structures, the hitherto reported properties of thienoacene-based OFETs are rather diverse. This Review focuses on four classes of thienoacenes, which are classified in terms of their chemical structures, and elucidates the molecular electronic structure of each class. The packing structures of thienoacenes and the thus-estimated solid-state electronic structures are correlated to their carrier transport properties in OFET devices. With this perspective of the molecular structures of thienoacenes and their carrier transport properties in OFET devices, the structure-property relationships in thienoacene-based organic semiconductors are discussed. The discussion provides insight into new molecular design strategies for the development of superior organic semiconductors. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Identification of defects in semiconductors

    CERN Document Server

    Stavola, Michael; Weber, Eicke R; Stavola, Michael

    1998-01-01

    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 indeed that this traditi...

  13. The Electrical Characteristics of The N-Organic Semiconductor/P-Inorganic Semiconductor Diode

    International Nuclear Information System (INIS)

    Aydin, M. E.

    2008-01-01

    n-organic semiconductor (PEDOT) / p-inorganic semiconductor Si diode was formed by deep coating method. The method has been achieved by coating n-inorganic semiconductor PEDOT on top of p-inorganic semiconductor. The n-organic semiconductor PEDOT/ p-inorganic semiconductor diode demonstrated rectifying behavior by the current-voltage (I-V) curves studied at room temperature. The barrier height , ideality factor values were obtained as of 0.88 eV and 1.95 respectively. The diode showed non-ideal I-V behavior with an ideality factor greater than unity that could be ascribed to the interfacial layer

  14. Toleration out of respect?

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2013-01-01

    Under conditions of pluralism different cultures, interests or values can come into conflict, which raises the problem of how to secure peaceful co-existence. The idea of toleration historically emerged as an answer to this problem. Recently Rainer Forst has argued that toleration should not just...... be based on a modus vivendi designed to secure peaceful co-existence, but should be based on moral reasons. Forst therefore advances what he calls the ‘respect conception’ of toleration as an in itself morally desirable type of relationship, which is furthermore the only conception of toleration...... that avoids various so-called ‘paradoxes of toleration’. The paper first examines whether Forst’s respect conception can be applied descriptively to distinguish between actual patterns of behaviour and classify different acts of toleration. Then the focus is shifted to toleration out of respect as a normative...

  15. CO2 sensor versus Volatile Organic Compounds (VOC) sensor – analysis of field measurement data and implications for demand controlled ventilation

    DEFF Research Database (Denmark)

    Kolarik, Jakub

    2014-01-01

    The study investigated performance of two commercially available non-selective metal oxide semiconductor VOC sensors and two commercially available non dispersive infrared CO2 sensors installed in one person office. The office was equipped with demand controlled ventilation. The signals from VOC...

  16. Sensors, Volume 4, Thermal Sensors

    Science.gov (United States)

    Scholz, Jorg; Ricolfi, Teresio

    1996-12-01

    'Sensors' is the first self-contained series to deal with the whole area of sensors. It describes general aspects, technical and physical fundamentals, construction, function, applications and developments of the various types of sensors. This volume describes the construction and applicational aspects of thermal sensors while presenting a rigorous treatment of the underlying physical principles. It provides a unique overview of the various categories of sensors as well as of specific groups, e.g. temperature sensors (resistance thermometers, thermocouples, and radiation thermometers), noise and acoustic thermometers, heat-flow and mass-flow sensors. Specific facettes of applications are presented by specialists from different fields including process control, automotive technology and cryogenics. This volume is an indispensable reference work and text book for both specialists and newcomers, researchers and developers.

  17. Tolerance in Drosophila

    OpenAIRE

    Atkinson, Nigel S.

    2009-01-01

    The set of genes that underlie ethanol tolerance (inducible resistance) are likely to overlap with the set of genes responsible for ethanol addiction. Whereas addiction is difficult to recognize in simple model systems, behavioral tolerance is readily identifiable and can be induced in large populations of animals. Thus, tolerance lends itself to analysis in model systems with powerful genetics. Drosophila melanogaster has been used by a variety of laboratories for the identification of genes...

  18. New Icosahedral Boron Carbide Semiconductors

    Science.gov (United States)

    Echeverria Mora, Elena Maria

    Novel semiconductor boron carbide films and boron carbide films doped with aromatic compounds have been investigated and characterized. Most of these semiconductors were formed by plasma enhanced chemical vapor deposition. The aromatic compound additives used, in this thesis, were pyridine (Py), aniline, and diaminobenzene (DAB). As one of the key parameters for semiconducting device functionality is the metal contact and, therefore, the chemical interactions or band bending that may occur at the metal/semiconductor interface, X-ray photoemission spectroscopy has been used to investigate the interaction of gold (Au) with these novel boron carbide-based semiconductors. Both n- and p-type films have been tested and pure boron carbide devices are compared to those containing aromatic compounds. The results show that boron carbide seems to behave differently from other semiconductors, opening a way for new analysis and approaches in device's functionality. By studying the electrical and optical properties of these films, it has been found that samples containing the aromatic compound exhibit an improvement in the electron-hole separation and charge extraction, as well as a decrease in the band gap. The hole carrier lifetimes for each sample were extracted from the capacitance-voltage, C(V), and current-voltage, I(V), curves. Additionally, devices, with boron carbide with the addition of pyridine, exhibited better collection of neutron capture generated pulses at ZERO applied bias, compared to the pure boron carbide samples. This is consistent with the longer carrier lifetimes estimated for these films. The I-V curves, as a function of external magnetic field, of the pure boron carbide films and films containing DAB demonstrate that significant room temperature negative magneto-resistance (> 100% for pure samples, and > 50% for samples containing DAB) is possible in the resulting dielectric thin films. Inclusion of DAB is not essential for significant negative magneto

  19. Conductivity in transparent oxide semiconductors.

    Science.gov (United States)

    King, P D C; Veal, T D

    2011-08-24

    Despite an extensive research effort for over 60 years, an understanding of the origins of conductivity in wide band gap transparent conducting oxide (TCO) semiconductors remains elusive. While TCOs have already found widespread use in device applications requiring a transparent contact, there are currently enormous efforts to (i) increase the conductivity of existing materials, (ii) identify suitable alternatives, and (iii) attempt to gain semiconductor-engineering levels of control over their carrier density, essential for the incorporation of TCOs into a new generation of multifunctional transparent electronic devices. These efforts, however, are dependent on a microscopic identification of the defects and impurities leading to the high unintentional carrier densities present in these materials. Here, we review recent developments towards such an understanding. While oxygen vacancies are commonly assumed to be the source of the conductivity, there is increasing evidence that this is not a sufficient mechanism to explain the total measured carrier concentrations. In fact, many studies suggest that oxygen vacancies are deep, rather than shallow, donors, and their abundance in as-grown material is also debated. We discuss other potential contributions to the conductivity in TCOs, including other native defects, their complexes, and in particular hydrogen impurities. Convincing theoretical and experimental evidence is presented for the donor nature of hydrogen across a range of TCO materials, and while its stability and the role of interstitial versus substitutional species are still somewhat open questions, it is one of the leading contenders for yielding unintentional conductivity in TCOs. We also review recent work indicating that the surfaces of TCOs can support very high carrier densities, opposite to the case for conventional semiconductors. In thin-film materials/devices and, in particular, nanostructures, the surface can have a large impact on the total

  20. Spintronic effects in metallic, semiconductor, metal-oxide and metal-semiconductor heterostructures

    Energy Technology Data Exchange (ETDEWEB)

    Bratkovsky, A M [Hewlett-Packard Laboratories, 1501 Page Mill Road, MS 1123, Palo Alto, CA 94304 (United States)

    2008-02-15

    Spintronics is a rapidly growing field focusing on phenomena and related devices essentially dependent on spin transport. Some of them are already an established part of microelectronics. We review recent theoretical and experimental advances in achieving large spin injection efficiency (polarization of current) and accumulated spin polarization. These include tunnel and giant magnetoresistance, spin-torque and spin-orbit effects on electron transport in various heterostructures. We give a microscopic description of spin tunneling through oxide and modified Schottky barriers between a ferromagnet (FM) and a semiconductor (S). It is shown that in such FM-S junctions electrons with a certain spin projection can be efficiently injected into (or extracted from) S, while electrons with the opposite spin can accumulate in S near the interface. The criterion for efficient injection is opposite to a known Rashba criterion, since the barrier should be rather transparent. In degenerate semiconductors, extraction of spin can proceed at low temperatures. We mention a few novel spin-valve ultrafast devices with small dissipated power: a magnetic sensor, a spin transistor, an amplifier, a frequency multiplier, a square-law detector and a source of polarized radiation. We also discuss effects related to spin-orbital interactions, such as the spin Hall effect (SHE) and a recently predicted positive magnetoresistance accompanying SHE. Some esoteric devices such as 'spinFET', interacting spin logic and spin-based quantum computing are discussed and problems with their realization are highlighted. We demonstrate that the so-called 'ferroelectric tunnel junctions' are unlikely to provide additional functionality because in all realistic situations the ferroelectric barrier would be split into domains by the depolarizing field.

  1. Spintronic effects in metallic, semiconductor, metal-oxide and metal-semiconductor heterostructures

    International Nuclear Information System (INIS)

    Bratkovsky, A M

    2008-01-01

    Spintronics is a rapidly growing field focusing on phenomena and related devices essentially dependent on spin transport. Some of them are already an established part of microelectronics. We review recent theoretical and experimental advances in achieving large spin injection efficiency (polarization of current) and accumulated spin polarization. These include tunnel and giant magnetoresistance, spin-torque and spin-orbit effects on electron transport in various heterostructures. We give a microscopic description of spin tunneling through oxide and modified Schottky barriers between a ferromagnet (FM) and a semiconductor (S). It is shown that in such FM-S junctions electrons with a certain spin projection can be efficiently injected into (or extracted from) S, while electrons with the opposite spin can accumulate in S near the interface. The criterion for efficient injection is opposite to a known Rashba criterion, since the barrier should be rather transparent. In degenerate semiconductors, extraction of spin can proceed at low temperatures. We mention a few novel spin-valve ultrafast devices with small dissipated power: a magnetic sensor, a spin transistor, an amplifier, a frequency multiplier, a square-law detector and a source of polarized radiation. We also discuss effects related to spin-orbital interactions, such as the spin Hall effect (SHE) and a recently predicted positive magnetoresistance accompanying SHE. Some esoteric devices such as 'spinFET', interacting spin logic and spin-based quantum computing are discussed and problems with their realization are highlighted. We demonstrate that the so-called 'ferroelectric tunnel junctions' are unlikely to provide additional functionality because in all realistic situations the ferroelectric barrier would be split into domains by the depolarizing field

  2. Spintronic effects in metallic, semiconductor, metal oxide and metal semiconductor heterostructures

    Science.gov (United States)

    Bratkovsky, A. M.

    2008-02-01

    Spintronics is a rapidly growing field focusing on phenomena and related devices essentially dependent on spin transport. Some of them are already an established part of microelectronics. We review recent theoretical and experimental advances in achieving large spin injection efficiency (polarization of current) and accumulated spin polarization. These include tunnel and giant magnetoresistance, spin-torque and spin-orbit effects on electron transport in various heterostructures. We give a microscopic description of spin tunneling through oxide and modified Schottky barriers between a ferromagnet (FM) and a semiconductor (S). It is shown that in such FM-S junctions electrons with a certain spin projection can be efficiently injected into (or extracted from) S, while electrons with the opposite spin can accumulate in S near the interface. The criterion for efficient injection is opposite to a known Rashba criterion, since the barrier should be rather transparent. In degenerate semiconductors, extraction of spin can proceed at low temperatures. We mention a few novel spin-valve ultrafast devices with small dissipated power: a magnetic sensor, a spin transistor, an amplifier, a frequency multiplier, a square-law detector and a source of polarized radiation. We also discuss effects related to spin-orbital interactions, such as the spin Hall effect (SHE) and a recently predicted positive magnetoresistance accompanying SHE. Some esoteric devices such as 'spinFET', interacting spin logic and spin-based quantum computing are discussed and problems with their realization are highlighted. We demonstrate that the so-called 'ferroelectric tunnel junctions' are unlikely to provide additional functionality because in all realistic situations the ferroelectric barrier would be split into domains by the depolarizing field.

  3. n-Channel semiconductor materials design for organic complementary circuits.

    Science.gov (United States)

    Usta, Hakan; Facchetti, Antonio; Marks, Tobin J

    2011-07-19

    Organic semiconductors have unique properties compared to traditional inorganic materials such as amorphous or crystalline silicon. Some important advantages include their adaptability to low-temperature processing on flexible substrates, low cost, amenability to high-speed fabrication, and tunable electronic properties. These features are essential for a variety of next-generation electronic products, including low-power flexible displays, inexpensive radio frequency identification (RFID) tags, and printable sensors, among many other applications. Accordingly, the preparation of new materials based on π-conjugated organic molecules or polymers has been a central scientific and technological research focus over the past decade. Currently, p-channel (hole-transporting) materials are the leading class of organic semiconductors. In contrast, high-performance n-channel (electron-transporting) semiconductors are relatively rare, but they are of great significance for the development of plastic electronic devices such as organic field-effect transistors (OFETs). In this Account, we highlight the advances our team has made toward realizing moderately and highly electron-deficient n-channel oligomers and polymers based on oligothiophene, arylenediimide, and (bis)indenofluorene skeletons. We have synthesized and characterized a "library" of structurally related semiconductors, and we have investigated detailed structure-property relationships through optical, electrochemical, thermal, microstructural (both single-crystal and thin-film), and electrical measurements. Our results reveal highly informative correlations between structural parameters at various length scales and charge transport properties. We first discuss oligothiophenes functionalized with perfluoroalkyl and perfluoroarene substituents, which represent the initial examples of high-performance n-channel semiconductors developed in this project. The OFET characteristics of these compounds are presented with an

  4. Review: Semiconductor Piezoresistance for Microsystems.

    Science.gov (United States)

    Barlian, A Alvin; Park, Woo-Tae; Mallon, Joseph R; Rastegar, Ali J; Pruitt, Beth L

    2009-01-01

    Piezoresistive sensors are among the earliest micromachined silicon devices. The need for smaller, less expensive, higher performance sensors helped drive early micromachining technology, a precursor to microsystems or microelectromechanical systems (MEMS). The effect of stress on doped silicon and germanium has been known since the work of Smith at Bell Laboratories in 1954. Since then, researchers have extensively reported on microscale, piezoresistive strain gauges, pressure sensors, accelerometers, and cantilever force/displacement sensors, including many commercially successful devices. In this paper, we review the history of piezoresistance, its physics and related fabrication techniques. We also discuss electrical noise in piezoresistors, device examples and design considerations, and alternative materials. This paper provides a comprehensive overview of integrated piezoresistor technology with an introduction to the physics of piezoresistivity, process and material selection and design guidance useful to researchers and device engineers.

  5. Fabrication and performance of pressure-sensing device consisting of electret film and organic semiconductor

    Science.gov (United States)

    Kodzasa, Takehito; Nobeshima, Daiki; Kuribara, Kazunori; Uemura, Sei; Yoshida, Manabu

    2017-04-01

    We propose a new concept of a pressure-sensitive device that consists of an organic electret film and an organic semiconductor. This device exhibits high sensitivity and selectivity against various types of pressure. The sensing mechanism of this device originates from a modulation of the electric conductivity of the organic semiconductor film induced by the interaction between the semiconductor film and the charged electret film placed face to face. It is expected that a complicated sensor array will be fabricated by using a roll-to-roll manufacturing system, because this device can be prepared by an all-printing and simple lamination process without high-level positional adjustment for printing processes. This also shows that this device with a simple structure is suitable for application to a highly flexible device array sheet for an Internet of Things (IoT) or wearable sensing system.

  6. Gas Sensor

    KAUST Repository

    Luebke, Ryan

    2015-01-22

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  7. Gas Sensor

    KAUST Repository

    Luebke, Ryan; Eddaoudi, Mohamed; Omran, Hesham; Belmabkhout, Youssef; Shekhah, Osama; Salama, Khaled N.

    2015-01-01

    A gas sensor using a metal organic framework material can be fully integrated with related circuitry on a single substrate. In an on-chip application, the gas sensor can result in an area-efficient fully integrated gas sensor solution. In one aspect, a gas sensor can include a first gas sensing region including a first pair of electrodes, and a first gas sensitive material proximate to the first pair of electrodes, wherein the first gas sensitive material includes a first metal organic framework material.

  8. Sensor web

    Science.gov (United States)

    Delin, Kevin A. (Inventor); Jackson, Shannon P. (Inventor)

    2011-01-01

    A Sensor Web formed of a number of different sensor pods. Each of the sensor pods include a clock which is synchronized with a master clock so that all of the sensor pods in the Web have a synchronized clock. The synchronization is carried out by first using a coarse synchronization which takes less power, and subsequently carrying out a fine synchronization to make a fine sync of all the pods on the Web. After the synchronization, the pods ping their neighbors to determine which pods are listening and responded, and then only listen during time slots corresponding to those pods which respond.

  9. Electronic properties of semiconductor surfaces and metal/semiconductor interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Tallarida, M.

    2005-05-15

    This thesis reports investigations of the electronic properties of a semiconductor surface (silicon carbide), a reactive metal/semiconductor interface (manganese/silicon) and a non-reactive metal/semiconductor interface (aluminum-magnesium alloy/silicon). The (2 x 1) reconstruction of the 6H-SiC(0001) surface has been obtained by cleaving the sample along the (0001) direction. This reconstruction has not been observed up to now for this compound, and has been compared with those of similar elemental semiconductors of the fourth group of the periodic table. This comparison has been carried out by making use of photoemission spectroscopy, analyzing the core level shifts of both Si 2p and C 1s core levels in terms of charge transfer between atoms of both elements and in different chemical environments. From this comparison, a difference between the reconstruction on the Si-terminated and the C-terminated surface was established, due to the ionic nature of the Si-C bond. The growth of manganese films on Si(111) in the 1-5 ML thickness range has been studied by means of LEED, STM and photoemission spectroscopy. By the complementary use of these surface science techniques, two different phases have been observed for two thickness regimes (<1 ML and >1 ML), which exhibit a different electronic character. The two reconstructions, the (1 x 1)-phase and the ({radical}3 x {radical}3)R30 -phase, are due to silicide formation, as observed in core level spectroscopy. The growth proceeds via island formation in the monolayer regime, while the thicker films show flat layers interrupted by deep holes. On the basis of STM investigations, this growth mode has been attributed to strain due to lattice mismatch between the substrate and the silicide. Co-deposition of Al and Mg onto a Si(111) substrate at low temperature (100K) resulted in the formation of thin alloy films. By varying the relative content of both elements, the thin films exhibited different electronic properties

  10. Roadmap on semiconductor-cell biointerfaces

    Science.gov (United States)

    Tian, Bozhi; Xu, Shuai; Rogers, John A.; Cestellos-Blanco, Stefano; Yang, Peidong; Carvalho-de-Souza, João L.; Bezanilla, Francisco; Liu, Jia; Bao, Zhenan; Hjort, Martin; Cao, Yuhong; Melosh, Nicholas; Lanzani, Guglielmo; Benfenati, Fabio; Galli, Giulia; Gygi, Francois; Kautz, Rylan; Gorodetsky, Alon A.; Kim, Samuel S.; Lu, Timothy K.; Anikeeva, Polina; Cifra, Michal; Krivosudský, Ondrej; Havelka, Daniel; Jiang, Yuanwen

    2018-05-01

    This roadmap outlines the role semiconductor-based materials play in understanding the complex biophysical dynamics at multiple length scales, as well as the design and implementation of next-generation electronic, optoelectronic, and mechanical devices for biointerfaces. The roadmap emphasizes the advantages of semiconductor building blocks in interfacing, monitoring, and manipulating the activity of biological components, and discusses the possibility of using active semiconductor-cell interfaces for discovering new signaling processes in the biological world.

  11. Chemical Gas Sensors for Aeronautic and Space Applications

    Science.gov (United States)

    Hunter, Gary W.; Chen, Liang-Yu; Neudeck, Philip G.; Knight, Dak; Liu, Chung-Chiun; Wu, Quing-Hai; Zhou, Huan-Jun

    1997-01-01

    Aeronautic and space applications require the development of chemical sensors with capabilities beyond those of commercially available sensors. Two areas of particular interest are safety monitoring and emission monitoring. In safety monitoring, detection of low concentrations of hydrogen at potentially low temperatures is important while for emission monitoring the detection of nitrogen oxides, hydrogen, hydrocarbons and oxygen is of interest. This paper discusses the needs of aeronautic and space applications and the point-contact sensor technology being developed to address these needs. The development of these sensors is based on progress in two types of technology: (1) Micromachining and microfabrication technology to fabricate miniaturized sensors. (2) The development of high temperature semiconductors, especially silicon carbide. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. The number of dual-use commercial applications of this microfabricated gas sensor technology make this general area of sensor development a field of significant interest.

  12. Test beam evaluation of newly developed n-in-p planar pixel sensors for use in a high radiation environment

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, K., E-mail: kimihiko@hep.phys.titech.ac.jp [Institute of Science and Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8551 (Japan); Yamaguchi, D.; Motohashi, K. [Institute of Science and Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8551 (Japan); Nakamura, K.; Unno, Y. [Institute of Particle and Nuclear Study, KEK, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Jinnouchi, O. [Institute of Science and Engineering, Tokyo Institute of Technology, Ookayama 2-12-1, Meguro-ku, Tokyo 152-8551 (Japan); Altenheiner, S. [Experimentelle Physik IV, Technische Universität Dortmund, 44221 Dortmund (Germany); Blue, A. [School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, Scotland (United Kingdom); Bomben, M. [CNRS/IN2P3 (France); Laboratoire de physique nucléaire et de hautes energies (LPNHE), Univ. Paris-UMPC, 4 Place Jussieu, 75005 Paris (France); Univ. Paris Diderot (France); Butter, A. [LAL, University Paris-Sud (France); CNRS/IN2P3 (France); Université Paris-Saclay, Orsay (France); Cervelli, A. [Universität Bern, Laboratory for High Energy Physics, Sidlerstrasse 55, CH-3012 Bern (Switzerland); Crawley, S. [School of Physics and Astronomy, University of Glasgow, Glasgow, G12 8QQ, Scotland (United Kingdom); Ducourthial, A. [CNRS/IN2P3 (France); Laboratoire de physique nucléaire et de hautes energies (LPNHE), Univ. Paris-UMPC, 4 Place Jussieu, 75005 Paris (France); Univ. Paris Diderot (France); Gisen, A. [Experimentelle Physik IV, Technische Universität Dortmund, 44221 Dortmund (Germany); Hagihara, M. [Institute of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki 305-8751 (Japan); and others

    2016-09-21

    Radiation-tolerant n-in-p planar pixel sensors have been under development in cooperation with Hamamatsu Photonics K.K. (HPK). This is geared towards applications in high-radiation environments, such as for the future Inner Tracker (ITk) placed in the innermost part of the ATLAS detector in the high luminosity LHC (HL-LHC) experiment. Prototypes of those sensors have been produced, irradiated, and evaluated over the last few years. In the previous studies, it was reported that significant drops in the detection efficiency were observed after irradiation, especially under bias structures. The bias structures are made up of poly-Si or Al bias rails and poly-Si bias resistors. The structure is implemented on the sensors to allow quality checks to be performed before the bump-bonding process, and to ensure that charge generated in floating pixels due to non-contacting or missing bump-bonds is dumped in a controlled way in order to avoid noise. To minimize the efficiency drop, several new pixel structures have been designed with bias rails and bias resistors relocated. Several test beams have been carried out to evaluate the drops in the detection efficiency of the new sensor structures after irradiation. Newly developed sensor modules were irradiated with proton-beams at the Cyclotron and Radio-Isotope Center (CYRIC) in Tohoku University to see the effect of sensor-bulk damage and surface charge-up. An irradiation with γ-rays was also carried out at Takasaki Advanced Radiation Research Center, with the goal of decoupling the effect of surface charge-up from that of bulk damage. Those irradiated sensors have been evaluated with particle beams at DESY and CERN. Comparison between different sensor structures confirmed significant improvements in minimizing efficiency loss under the bias structures after irradiation. The results from γ-irradiation also enabled cross-checking the results of a semiconductor technology simulation program (TCAD). - Highlights: • The

  13. Scanning electron microscopy of semiconductor materials

    International Nuclear Information System (INIS)

    Bresse, J.F.; Dupuy, M.

    1978-01-01

    The use of scanning electron microscopy in semiconductors opens up a large field of use. The operating modes lending themselves to the study of semiconductors are the induced current, cathodoluminescence and the use of the potential contrast which can also be applied very effectively to the study of the devices (planar in particular). However, a thorough knowledge of the mechanisms of the penetration of electrons, generation and recombination of generated carriers in a semiconductor is necessary in order to attain a better understanding of the operating modes peculiar to semiconductors [fr

  14. Reflection technique for thermal mapping of semiconductors

    Science.gov (United States)

    Walter, Martin J.

    1989-06-20

    Semiconductors may be optically tested for their temperatures by illuminating them with tunable monochromatic electromagnetic radiation and observing the light reflected off of them. A transition point will occur when the wavelength of the light corresponds with the actual band gap energy of the semiconductor. At the transition point, the image of the semiconductor will appreciably darken as the light is transmitted through it, rather than being reflected off of it. The wavelength of the light at the transition point corresponds to the actual band gap energy and the actual temperature of the semiconductor.

  15. Metallurgy and purification of semiconductor materials

    International Nuclear Information System (INIS)

    Mughal, G.R.; Ali, M.M.; Ali, I.

    1996-01-01

    In this article the metallurgical aspects of semiconductor science and technology have been stressed here rather than of the physical and electronic aspect of the subject. Semiconductor technology has not merely presented the metallurgist with new challenges. The ease with which the semiconductor planes cleave make possible, the preparation and study of virgin surface. Semiconductor materials were being widely employed in the study of sub-boundaries and structures and can largely contribute to the study of certain aspects of nucleation and growth, precipitation phenomena, mechanical behaviour, in metallurgy. (A.B.)

  16. Emission and Absorption Entropy Generation in Semiconductors

    DEFF Research Database (Denmark)

    Reck, Kasper; Varpula, Aapo; Prunnila, Mika

    2013-01-01

    While emission and absorption entropy generation is well known in black bodies, it has not previously been studied in semiconductors, even though semiconductors are widely used for solar light absorption in modern solar cells [1]. We present an analysis of the entropy generation in semiconductor...... materials due to emission and absorption of electromagnetic radiation. It is shown that the emission and absorption entropy generation reduces the fundamental limit on the efficiency of any semiconductor solar cell even further than the Landsberg limit. The results are derived from purely thermodynamical...

  17. Semiconductor Lasers Stability, Instability and Chaos

    CERN Document Server

    Ohtsubo, Junji

    2008-01-01

    This monograph describes fascinating recent progress in the field of chaos, stability and instability of semiconductor lasers. Applications and future prospects are discussed in detail. The book emphasizes the various dynamics induced in semiconductor lasers by optical and electronic feedback, optical injection, and injection current modulation. Recent results of both theoretical and experimental investigations are presented. Demonstrating applications of semiconductor laser chaos, control and noise, Semiconductor Lasers describes suppression and chaotic secure communications. For those who are interested in optics but not familiar with nonlinear systems, a brief introduction to chaos analysis is presented.

  18. Compromise and Toleration

    DEFF Research Database (Denmark)

    Rostbøll, Christian F.

    Political compromise is akin to toleration, since both consist of an "agreement to disagree." Compromise and toleration also share a predicament of being regarded as ambiguous virtues that require of us to accept something we actually regard as wrong. However, we misunderstand the nature, justifi...... in compromise are more stringent than those for being tolerated. Still, the limits of compromise cannot be drawn to narrowly if it is to remain its value as a form of agreement that respects and embodies the differences of opinion in society.......Political compromise is akin to toleration, since both consist of an "agreement to disagree." Compromise and toleration also share a predicament of being regarded as ambiguous virtues that require of us to accept something we actually regard as wrong. However, we misunderstand the nature......, justification, and limits of compromise if we see it merely as a matter of toleration. While toleration is mainly a matter of accepting citizens' equal right to co-existence as subjects to law, political compromise includes the parties in making law – it makes them co-authors of law. Toleration entails...

  19. Tolerances in micro manufacturing

    DEFF Research Database (Denmark)

    Hansen, Hans Nørgaard; Zhang, Yang; Islam, Aminul

    This paper describes a method for analysis of tolerances in micro manufacturing. It proposes a mapping oftolerances to dimensions and compares this with current available international standards. The analysisdocuments that tolerances are not scaled down as the absolute dimension. In practice...

  20. Fault tolerant computing systems

    International Nuclear Information System (INIS)

    Randell, B.

    1981-01-01

    Fault tolerance involves the provision of strategies for error detection damage assessment, fault treatment and error recovery. A survey is given of the different sorts of strategies used in highly reliable computing systems, together with an outline of recent research on the problems of providing fault tolerance in parallel and distributed computing systems. (orig.)

  1. Toleration out of respect?

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2014-01-01

    be based on a modus vivendi designed to secure peaceful co-existence, but should be based on moral reasons. Forst therefore advances what he calls the ‘respect conception’ of toleration as an in itself morally desirable type of relationship, which is furthermore the only conception of toleration...

  2. Recognition and Toleration

    DEFF Research Database (Denmark)

    Lægaard, Sune

    2010-01-01

    Recognition and toleration are ways of relating to the diversity characteristic of multicultural societies. The article concerns the possible meanings of toleration and recognition, and the conflict that is often claimed to exist between these two approaches to diversity. Different forms or inter...

  3. Remember Tolerance Differently

    DEFF Research Database (Denmark)

    Tønder, Lars

    2012-01-01

    This essay questions the linear conception of history which often accompanies the way contemporary democratic theory tends to disavow tolerance's discontinuities and remainders. In the spirit of Foucault's genealogy of descent, the idea is to develop a new sense of tolerance's history, not by inv......This essay questions the linear conception of history which often accompanies the way contemporary democratic theory tends to disavow tolerance's discontinuities and remainders. In the spirit of Foucault's genealogy of descent, the idea is to develop a new sense of tolerance's history......, not by invoking a critique external to contemporary democratic theory, but by witnessing the history of tolerance paraliptically, with an eye to what it obscures and yet presupposes....

  4. Ultrafast laser-semiconductor interactions

    International Nuclear Information System (INIS)

    Schile, L.A.

    1996-01-01

    Studies of the ultrafast (< 100 fs) interactions of infrared, sub-100 fs laser pulses with IR, photosensitive semiconductor materials InGaAs, InSb, and HgCdTe are reported. Both the carrier dynamics and the associated Terahertz radiation from these materials are discussed. The most recent developments of femtosecond (< 100 fs) Optical Parametric Oscillators (OPO) has extended the wavelength range from the visible to 5.2 μm. The photogenerated semiconductor free carrier dynamics are determined in the 77 to 300 degrees K temperature range using the Transmission Correlation Peak (TCP) method. The electron-phonon scattering times are typically 200 - 600 fs. Depending upon the material composition and substrate on which the IR crystalline materials are deposited, the nonlinear TCP absorption gives recombination rates as fast as 10's of picoseconds. For the HgCdTe, there exists a 400 fs electron-phonon scattering process along with a much longer 3600 fs loss process. Studies of the interactions of these ultrashort laser pulses with semiconductors produce Terahertz (Thz) radiative pulses. With undoped InSb, there is a substantial change in the spectral content of this THz radiation between 80 - 260 degrees K while the spectrum of Te-doped InSb remains nearly unchanged, an effect attributed to its mobility being dominated by impurity scattering. At 80 degrees K, the terahertz radiation from undoped InSb is dependent on wavelength, with both a higher frequency spectrum and much larger amplitudes generated at longer wavelengths. No such effect is observed at 260 degrees K. Finally, new results on the dependence of the emitted THz radiation on the InSb crystal's orientation is presented

  5. Piezoresistive silicon pressure sensors in cryogenic environment

    Science.gov (United States)

    Kahng, Seun K.; Chapman, John J.

    1989-01-01

    This paper presents data on low-temperature measurements of silicon pressure sensors. It was found that both the piezoresistance coefficients and the charge-carrier mobility increase with decreasing temperature. For lightly doped semiconductor materials, the density of free charge carriers decreases with temperature and can freeze out eventually. However, the effect of carrier freeze-out can be minimized by increasing the impurity content to higher levels, at which the temperature dependency of piezoresistance coefficients is reduced. An impurity density of 1 x 10 to the 19th/cu cm was found to be optimal for cryogenic applications of pressure sensor dies.

  6. Physicochemical and Electrophysical Properties of Metal/Semiconductor Containing Nanostructured Composites

    Science.gov (United States)

    Gerasimov, G. N.; Gromov, V. F.; Trakhtenberg, L. I.

    2018-06-01

    The properties of nanostructured composites based on metal oxides and metal-polymer materials are analyzed, along with ways of preparing them. The effect the interaction between metal and semiconductor nanoparticles has on the conductivity, photoconductivity, catalytic activity, and magnetic, dielectric, and sensor properties of nanocomposites is discussed. It is shown that as a result of this interaction, a material can acquire properties that do not exist in systems of isolated particles. The transfer of electrons between metal particles of different sizes in polymeric matrices leads to specific dielectric losses, and to an increase in the rate and a change in the direction of chemical reactions catalyzed by these particles. The interaction between metal-oxide semiconductor particles results in the electronic and chemical sensitization of sensor effects in nanostructured composite materials. Studies on creating molecular machines (Brownian motors), devices for magnetic recording of information, and high-temperature superconductors based on nanostructured systems are reviewed.

  7. High Temperature, Wireless Seismometer Sensor for Venus

    Science.gov (United States)

    Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Meredith, Roger D.; Beheim, Glenn M.; Hunter Gary W.; Kiefer, Walter S.

    2012-01-01

    Space agency mission plans state the need to measure the seismic activity on Venus. Because of the high temperature on Venus (462? C average surface temperature) and the difficulty in placing and wiring multiple sensors using robots, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents the description and proof of concept measurements of a high temperature, wireless seismometer sensor for Venus. A variation in inductance of a coil caused by the movement of an aluminum probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 700 Hz in the transmitted signal from the oscillator/sensor system at 426? C. This result indicates that the concept may be used on Venus.

  8. Ion implantation in semiconductor bodies

    International Nuclear Information System (INIS)

    Badawi, M.H.

    1984-01-01

    Ions are selectively implanted into layers of a semiconductor substrate of, for example, semi-insulating gallium arsenide via a photoresist implantation mask and a metallic layer of, for example, titanium disposed between the substrate surface and the photoresist mask. After implantation the mask and metallic layer are removed and the substrate heat treated for annealing purposes. The metallic layer acts as a buffer layer and prevents possible contamination of the substrate surface, by photoresist residues, at the annealing stage. Such contamination would adversely affect the electrical properties of the substrate surface, particularly gallium arsenide substrates. (author)

  9. Method of manufacturing semiconductor devices

    International Nuclear Information System (INIS)

    Sun, Y.S.E.

    1980-01-01

    A method of improving the electrical characteristics of semiconductor devices such as SCR's, rectifiers and triacs during their manufacture is described. The system consists of electron irradiation at an energy in excess of 250 KeV and most preferably between 1.5 and 12 MeV, producing an irradiation dose of between 5.10 12 and 5.10 15 electrons per sq. cm., and at a temperature in excess of 100 0 C preferably between 150 and 375 0 C. (U.K.)

  10. 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

  11. Theory of semiconductor laser cooling

    Science.gov (United States)

    Rupper, Greg

    Recently laser cooling of semiconductors has received renewed attention, with the hope that a semiconductor cooler might be able to achieve cryogenic temperatures. In order to study semiconductor laser cooling at cryogenic temperatures, it is crucial that the theory include both the effects of excitons and the electron-hole plasma. In this dissertation, I present a theoretical analysis of laser cooling of bulk GaAs based on a microscopic many-particle theory of absorption and luminescence of a partially ionized electron-hole plasma. This theory has been analyzed from a temperature 10K to 500K. It is shown that at high temperatures (above 300K), cooling can be modeled using older models with a few parameter changes. Below 200K, band filling effects dominate over Auger recombination. Below 30K excitonic effects are essential for laser cooling. In all cases, excitonic effects make cooling easier then predicted by a free carrier model. The initial cooling model is based on the assumption of a homogeneous undoped semiconductor. This model has been systematically modified to include effects that are present in real laser cooling experiments. The following modifications have been performed. (1) Propagation and polariton effects have been included. (2) The effect of p-doping has been included. (n-doping can be modeled in a similar fashion.) (3) In experiments, a passivation layer is required to minimize non-radiative recombination. The passivation results in a npn heterostructure. The effect of the npn heterostructure on cooling has been analyzed. (4) The effect of a Gaussian pump beam was analyzed and (5) Some of the parameters in the cooling model have a large uncertainty. The effect of modifying these parameters has been analyzed. Most of the extensions to the original theory have only had a modest effect on the overall results. However we find that the current passivation technique may not be sufficient to allow cooling. The passivation technique currently used appears

  12. Chaotic bursting in semiconductor lasers

    Science.gov (United States)

    Ruschel, Stefan; Yanchuk, Serhiy

    2017-11-01

    We investigate the dynamic mechanisms for low frequency fluctuations in semiconductor lasers subjected to delayed optical feedback, using the Lang-Kobayashi model. This system of delay differential equations displays pronounced envelope dynamics, ranging from erratic, so called low frequency fluctuations to regular pulse packages, if the time scales of fast oscillations and envelope dynamics are well separated. We investigate the parameter regions where low frequency fluctuations occur and compute their Lyapunov spectra. Using the geometric singular perturbation theory, we study this intermittent chaotic behavior and characterize these solutions as bursting slow-fast oscillations.

  13. Processing of insulators and semiconductors

    Science.gov (United States)

    Quick, Nathaniel R.; Joshi, Pooran C.; Duty, Chad Edward; Jellison, Jr., Gerald Earle; Angelini, Joseph Attilio

    2015-06-16

    A method is disclosed for processing an insulator material or a semiconductor material. The method includes pulsing a plasma lamp onto the material to diffuse a doping substance into the material, to activate the doping substance in the material or to metallize a large area region of the material. The method may further include pulsing a laser onto a selected region of the material to diffuse a doping substance into the material, to activate the doping substance in the material or to metallize a selected region of the material.

  14. Bistable amphoteric centers in semiconductors

    International Nuclear Information System (INIS)

    Nikitina, A. G.; Zuev, V. V.

    2008-01-01

    It is shown that, at thermodynamic equilibrium, the release of charge carriers from the localized states of bistable amphoteric centers into quasi-free states depends on the degree of compensation. This brings about different functional dependences of the concentration of free charge carriers on temperature. It is found that, in uncompensated semiconductors, the concentration of free charge carriers follows the same dependence in the case of bistable amphoteric centers and bistable amphoteric U - centers, although the distributions of charge carriers over the charge states and configurations are different for these types of centers. The results can be used for interpreting various experimental data insufficiently explained in the context of the traditional approach

  15. Electron beam writing on semiconductors

    International Nuclear Information System (INIS)

    Bierhenke, H.; Kutzer, E.; Pascher, A.; Plitzner, H.; Rummel, P.; Siemens A.G., Muenchen; Siemens A.G., Muenchen

    1979-08-01

    Reported are the results of the 3 1/2 year research project 'Electron beam Writing on Semiconductors'. Work has been done in the field of direct wafer exposure techniques, and of mask making. Described are resist technology, setting up of a research device, exploration of alignment procedures, manufacturing of devices and their radiation influence. Furthermore, investigations and measurements of an electron beam machine bought for mask making purposes, the development of LSI-circuits with this machine, the software necessary and important developments of digital subsystems are reported. (orig.) [de

  16. Trace analysis of semiconductor materials

    CERN Document Server

    Cali, J Paul; Gordon, L

    1964-01-01

    Trace Analysis of Semiconductor Materials is a guidebook concerned with procedures of ultra-trace analysis. This book discusses six distinct techniques of trace analysis. These techniques are the most common and can be applied to various problems compared to other methods. Each of the four chapters basically includes an introduction to the principles and general statements. The theoretical basis for the technique involved is then briefly discussed. Practical applications of the techniques and the different instrumentations are explained. Then, the applications to trace analysis as pertaining

  17. Miniature Sensor Probe for O2, CO2, and H2O Monitoring in Space Suits, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced space suits require lightweight, low-power, durable sensors for monitoring critical life support materials. No current compact sensors have the tolerance...

  18. Chemical sensors

    International Nuclear Information System (INIS)

    Hubbard, C.W.; Gordon, R.L.

    1987-05-01

    The revolution in analytical chemistry promised by recent developments in the field of chemical sensors has potential for significant positive impact on both research and production activities conducted by and for the Department of Energy. Analyses which were, in the past, performed only with a roomful of expensive equipment can now be performed with miniature solid-state electronic devices or small optical probes. Progress in the development of chemical sensors has been rapid, and the field is currently growing at a great rate. In accordance, Pacific Northwest Laboratory initiated a survey of recent literature so that contributors to active programs in research on analytical methods could be made aware of principles and applications of this new technology. This report presents the results of that survey. The sensors discussed here are divided into three types: micro solid-state devices, optical sensors, and piezoelectric crystal devices. The report is divided into three corresponding sections. The first section, ''Micro Solid-State Devices,'' discusses the design, operation, and application of electronic sensors that are produced in much the same way as standard solid-state electronic devices. The second section, ''Optrodes,'' covers the design and operation of chemical sensors that use fiber optics to detect chemically induced changes in optical properties. The final section, ''Piezoelectric Crystal Detectors,'' discusses two types of chemical sensors that depend on the changes in the properties of an oscillating piezoelectric crystal to detect the presence of certain materials. Advantages and disadvantages of each type of sensor are summarized in each section

  19. Measurement of reaction heats using a polysilicon-based microcalorimetric sensor

    NARCIS (Netherlands)

    Vereshchagina, E.; Wolters, Robertus A.M.; Gardeniers, Johannes G.E.

    2011-01-01

    In this work we present a low-cost, low-power, small sample volume microcalorimetric sensor for the measurement of reaction heats. The polysilicon-based microcalorimetric sensor combines several advantages: (i) complementary metal oxide semiconductor technology (CMOS) for future integration; (ii)

  20. Fault-tolerant and Diagnostic Methods for Navigation

    DEFF Research Database (Denmark)

    Blanke, Mogens

    2003-01-01

    to diagnose faults and autonomously provide valid navigation data, disregarding any faulty sensor data and use sensor fusion to obtain a best estimate for users. This paper discusses how diagnostic and fault-tolerant methods are applicable in marine systems. An example chosen is sensor fusion for navigation......Precise and reliable navigation is crucial, and for reasons of safety, essential navigation instruments are often duplicated. Hardware redundancy is mostly used to manually switch between instruments should faults occur. In contrast, diagnostic methods are available that can use analytic redundancy...