WorldWideScience

Sample records for arsenide junction-field-effect transistors

  1. Gallium nitride junction field-effect transistor

    Science.gov (United States)

    Zolper, John C.; Shul, Randy J.

    1999-01-01

    An all-ion implanted gallium-nitride (GaN) junction field-effect transistor (JFET) and method of making the same. Also disclosed are various ion implants, both n- and p-type, together with or without phosphorous co-implantation, in selected III-V semiconductor materials.

  2. Radiation dosimetry using junction field-effect transistor detectors

    International Nuclear Information System (INIS)

    The use of junction field effect transistors (JFET) has been studied by connecting them in a bridge circuit. With a suitable back-up circuit, it was possible to measure doses as well as dose-rates. It was possible to alter the sensitivity of the JFET bridge by varying the biasing components of the JFET. Easy temperature compensation was also possible. However, response of the JFET to radiation showed energy dependency similar to that of semiconductor diodes. (author)

  3. Field emission current from a junction field-effect transistor

    International Nuclear Information System (INIS)

    Fabrication of a titanium dioxide/carbon nanotube (TiO2/CNT)-based transistor is reported. The transistor can be considered as a combination of a field emission transistor and a junction field-effect transistor. Using direct current plasma-enhanced chemical vapor deposition (DC-PECVD) technique, CNTs were grown on a p-typed (100)-oriented silicon substrate. The CNTs were then covered by TiO2 nanoparticles 2–5 nm in size, using an atmospheric pressure CVD technique. In this device, TiO2/CNT junction is responsible for controlling the emission current. High on/off-current ratio and proper gate control are the most important advantages of device. A model based on Fowler–Nordheim equation is utilized for calculation of the emission current and the results are compared with experimental data. The effect of TiO2/CNT hetero-structure is also investigated, and well modeled

  4. Field emission current from a junction field-effect transistor

    Energy Technology Data Exchange (ETDEWEB)

    Monshipouri, Mahta; Abdi, Yaser, E-mail: y.abdi@ut.ac.ir [University of Tehran, Nano-Physics Research Laboratory, Department of Physics (Iran, Islamic Republic of)

    2015-04-15

    Fabrication of a titanium dioxide/carbon nanotube (TiO{sub 2}/CNT)-based transistor is reported. The transistor can be considered as a combination of a field emission transistor and a junction field-effect transistor. Using direct current plasma-enhanced chemical vapor deposition (DC-PECVD) technique, CNTs were grown on a p-typed (100)-oriented silicon substrate. The CNTs were then covered by TiO{sub 2} nanoparticles 2–5 nm in size, using an atmospheric pressure CVD technique. In this device, TiO{sub 2}/CNT junction is responsible for controlling the emission current. High on/off-current ratio and proper gate control are the most important advantages of device. A model based on Fowler–Nordheim equation is utilized for calculation of the emission current and the results are compared with experimental data. The effect of TiO{sub 2}/CNT hetero-structure is also investigated, and well modeled.

  5. Monolithic junction field-effect transistor charge preamplifier for calorimetry at high luminosity hadron colliders

    International Nuclear Information System (INIS)

    The outstanding noise and radiation hardness characteristics of epitaxial-channel junction field-effect transistors (JFET) suggest that a monolithic preamplifier based upon them may be able to meet the strict specifications for calorimetry at high luminosity colliders. Results obtained so far with a buried layer planar technology, among them an entire monolithic charge-sensitive preamplifier, are described

  6. A new model for four-terminal junction field-effect transistors

    Science.gov (United States)

    Ding, Hao; Liou, Juin J.; Green, Keith; Cirba, Claude R.

    2006-03-01

    This paper presents a compact and semi-empirical model for a four-terminal (independent top and bottom gates) junction field-effect transistor (JFET). The model describes the steady-state characteristics for all bias conditions with a unified equation. Moreover, the model provides a high degree of accuracy and continuity for the different operation regions, a critical factor for robust analog circuit simulations. Capacitance modeling is also included to describe the JFET small-signal behavior. The model has been implemented in Cadence framework via Verilog-A and compared with data measured from JFETs used at Texas Instruments.

  7. Gallium nitride junction field effect transistors for high-temperature operation

    Energy Technology Data Exchange (ETDEWEB)

    Zolper, J.C.; Shul, R.J.; Baca, A.G.; Hietala, V.M. [Sandia National Labs., Albuquerque, NM (United States); Pearton, S.J. [Univ. of Florida, Gainesville, FL (United States). Dept. of Materials Science and Engineering; Stall, R.A. [Emcore Corp., Somerset, NJ (United States); Wilson, R.G. [Hughes Research Labs., Malibu, CA (United States)

    1996-06-01

    GaN is an attractive material for use in high-temperature or high-power electronic devices due to its high bandgap (3.39 eV), high breakdown field ({approximately}5 {times} 10{sup 6} V/cm), high saturation drift velocity (2.7 {times} 10{sup 7} cm/s), and chemical inertness. To this end, Metal Semiconductor FETs (MESFETs), High Electron Mobility Transistors (HEMTs), Heterostructure FETs (HFETs), and Metal Insulator Semiconductor FETs (MISFETs) have all been reported based on epitaxial AlN/GaN structures (Khan 1993a,b; Binari 1994 and 1995). GaN Junction Field Effect Transistors (JFETs), however, had not been reported until recently (Zolper 1996b). JFETs are attractive for high-temperature operation due to the inherently higher thermal stability of the p/n junction gate of a JFET as compared to the Schottky barrier gate of a MESFET or HFET. In this paper the authors present the first results for elevated temperature performance of a GaN JFET. Although the forward gate properties are well behaved at higher temperatures, the reverse characteristics show increased leakage at elevated temperature. However, the increased date leakage alone does not explain the observed increase in drain current with temperature. Therefore, they believe this first device is limited by temperature activated substrate conduction.

  8. Contribution to the study of fluctuations in transistors (bipolar and junction field effect types)

    International Nuclear Information System (INIS)

    A brief review of the basic theory of fluctuations in semiconductors is given: shot, thermal low frequency noise. A measuring set has been built to draw noise spectrums (current or voltage). Noise parameters of bipolar transistors are given, mainly noise voltage. Noise current, noise factor and correlation between noise sources are also calculated. Measurements of noise parameters fit well with theory for various devices made in different technologies: alloyed, mesa, planar. Then we give results of the calculation of noise parameters in a FET starting from a simplified model of the device. Low frequency noise is taken into account. Measurements of the parameters and of the spectrum agree fairly well with the theory. Studies of low frequency noise versus temperature give the density and energy of traps located in the space charge layers and an idea of the impurity encountered in these space charge layers

  9. Characterization, Modeling and Design Parameters Identification of Silicon Carbide Junction Field Effect Transistor for Temperature Sensor Applications

    Directory of Open Access Journals (Sweden)

    Sofiane Khachroumi

    2010-01-01

    Full Text Available Sensor technology is moving towards wide-band-gap semiconductors providing high temperature capable devices. Indeed, the higher thermal conductivity of silicon carbide, (three times more than silicon, permits better heat dissipation and allows better cooling and temperature management. Though many temperature sensors have already been published, little endeavours have been invested in the study of silicon carbide junction field effect devices (SiC-JFET as a temperature sensor. SiC-JFETs devices are now mature enough and it is close to be commercialized. The use of its specific properties versus temperatures is the major focus of this paper. The SiC-JFETs output current-voltage characteristics are characterized at different temperatures. The saturation current and its on-resistance versus temperature are successfully extracted. It is demonstrated that these parameters are proportional to the absolute temperature. A physics-based model is also presented. Relationships between on-resistance and saturation current versus temperature are introduced. A comparative study between experimental data and simulation results is conducted. Important to note, the proposed model and the experimental results reflect a successful agreement as far as a temperature sensor is concerned.

  10. Characterization of vertical GaN p-n diodes and junction field-effect transistors on bulk GaN down to cryogenic temperatures

    Science.gov (United States)

    Kizilyalli, I. C.; Aktas, O.

    2015-12-01

    There is great interest in wide-bandgap semiconductor devices and most recently in vertical GaN structures for power electronic applications such as power supplies, solar inverters and motor drives. In this paper the temperature-dependent electrical behavior of vertical GaN p-n diodes and vertical junction field-effect transistors fabricated on bulk GaN substrates of low defect density (104 to 106 cm-2) is described. Homoepitaxial MOCVD growth of GaN on its native substrate and the ability to control the doping in the drift layers in GaN have allowed the realization of vertical device architectures with drift layer thicknesses of 6 to 40 μm and net carrier electron concentrations as low as 1 × 1015 cm-3. This parameter range is suitable for applications requiring breakdown voltages of 1.2 kV to 5 kV. Mg, which is used as a p-type dopant in GaN, is a relatively deep acceptor (E A ≈ 0.18 eV) and susceptible to freeze-out at temperatures below 200 K. The loss of holes in p-GaN has a deleterious effect on p-n junction behavior, p-GaN contacts and channel control in junction field-effect transistors at temperatures below 200 K. Impact ionization-based avalanche breakdown (BV > 1200 V) in GaN p-n junctions is characterized between 77 K and 423 K for the first time. At higher temperatures the p-n junction breakdown voltage improves due to increased phonon scattering. A positive temperature coefficient in the breakdown voltage is demonstrated down to 77 K; however, the device breakdown characteristics are not as abrupt at temperatures below 200 K. On the other hand, contact resistance to p-GaN is reduced dramatically above room temperature, improving the overall device performance in GaN p-n diodes in all cases except where the n-type drift region resistance dominates the total forward resistance. In this case, the electron mobility can be deconvolved and is found to decrease with T -3/2, consistent with a phonon scattering model. Also, normally-on vertical junction

  11. Characterization of vertical GaN p–n diodes and junction field-effect transistors on bulk GaN down to cryogenic temperatures

    International Nuclear Information System (INIS)

    There is great interest in wide-bandgap semiconductor devices and most recently in vertical GaN structures for power electronic applications such as power supplies, solar inverters and motor drives. In this paper the temperature-dependent electrical behavior of vertical GaN p–n diodes and vertical junction field-effect transistors fabricated on bulk GaN substrates of low defect density (104 to 106 cm−2) is described. Homoepitaxial MOCVD growth of GaN on its native substrate and the ability to control the doping in the drift layers in GaN have allowed the realization of vertical device architectures with drift layer thicknesses of 6 to 40 μm and net carrier electron concentrations as low as 1 × 1015 cm−3. This parameter range is suitable for applications requiring breakdown voltages of 1.2 kV to 5 kV. Mg, which is used as a p-type dopant in GaN, is a relatively deep acceptor (E A ≈ 0.18 eV) and susceptible to freeze-out at temperatures below 200 K. The loss of holes in p-GaN has a deleterious effect on p–n junction behavior, p-GaN contacts and channel control in junction field-effect transistors at temperatures below 200 K. Impact ionization-based avalanche breakdown (BV > 1200 V) in GaN p–n junctions is characterized between 77 K and 423 K for the first time. At higher temperatures the p–n junction breakdown voltage improves due to increased phonon scattering. A positive temperature coefficient in the breakdown voltage is demonstrated down to 77 K; however, the device breakdown characteristics are not as abrupt at temperatures below 200 K. On the other hand, contact resistance to p-GaN is reduced dramatically above room temperature, improving the overall device performance in GaN p–n diodes in all cases except where the n-type drift region resistance dominates the total forward resistance. In this case, the electron mobility can be deconvolved and is found to decrease with T −3/2, consistent with a phonon scattering model. Also, normally

  12. Indium arsenide nanowire field-effect transistors for pH and biological sensing

    International Nuclear Information System (INIS)

    Indium Arsenide is a high mobility semiconductor with a surface electron accumulation layer that allows ohmic electrical contact to metals. Here, we present nanowire devices based on this material as a platform for chemical and biological sensing. The sensing principle involves the binding of a charged species at the sensor surface transduced via field effect into a change in current flowing through the sensor. We show the sensitivity of the platform to the H+ ion concentration in solution as proof of principle and demonstrate the sensitivity to larger charged protein species. The sensors are highly reproducible and reach a detection limit of 10 pM for Avidin.

  13. Low-noise gallium-arsenide field-effect transistor preamplifiers for stochastic beam cooling systems

    International Nuclear Information System (INIS)

    The present noise performance, bandwidth capability and gain stability of bipolar and field-effect transistors, parametric amplifier, Schottky diode mixer and maser are summarized and compared in the 100 MHz to 40 GHz frequency range for stochastic beam cooling systems. Stability factor of GaAs FET's as a function of ambient temperature is presented and discussed. Performance data of several low-noise wide-band cryogenically cooled preamplifiers are presented including one with a noise figure of 0.35 dB over a bandwidth range of 150500 MHz operating at ambient temperature of 200K. Also, data are given on a broadband 1-2 GHz preamplifier having a noise figure of approximately 0.2 dB. The gain, operating noise temperature, stability, gain nonuniformity and phase-shift as function of frequency of interest for beam cooling systems are discussed

  14. Silicon Carbide Junction Field Effect Transistor Digital Logic Gates Demonstrated at 600 deg. C

    Science.gov (United States)

    Neudeck, Philip G.

    1998-01-01

    The High Temperature Integrated Electronics and Sensors (HTIES) Program at the NASA Lewis Research Center is currently developing silicon carbide (SiC) for use in harsh conditions where silicon, the semiconductor used in nearly all of today's electronics, cannot function. The HTIES team recently fabricated and demonstrated the first semiconductor digital logic gates ever to function at 600 C.

  15. Low-noise gallium-arsenide field-effect transistor preamplifiers for stochastic beam-cooling systems

    International Nuclear Information System (INIS)

    The present noise performance, bandwidth capability and gain stability of bipolar and field-effect transistors, parametric amplifier, Schottky diode mixer and maser are summarized and compared in the 100 MHz to 40 GHz frequency range for stochastic beam cooling systems. Stability factor of GaAs FET's as a function of ambient temperature is presented and discussed. Performance data of several low-noise wide-band cryogenically cooled preamplifiers are presented including one with a noise figure of 0.35 dB over a bandwidth range of 150 to 500 MHz operating at ambient temperature of 200K. Also, data are given on a broadband 1 to 2 GHz preamplifier having a noise figure of approximately 0.2 dB. The gain, operating noise temperature, stability, gain nonuniformity and phase-shift as function of frequency of interest for beam cooling systems are discussed

  16. Radiation effects on JFETS, MOSFETS, and bipolar transistors, as related to SSC circuit design

    International Nuclear Information System (INIS)

    Results of radiation effects on selected junction field-effect transistors, MOS transistors and bipolar junction transistors are presented. Evaluations include both dc parameters, as well as capacitance and noise evaluations. Detailed noise data were obtained both before and after 5-Mrad (gamma) total-dose exposure. SPICE radiation models are compared for a typical bipolar transistor charge-sensitive preamplifier

  17. Molecular beam epitaxy of gallium arsenide antimonide-based ultra-high-speed double heterojunction bipolar transistors and light emitting transistors

    Science.gov (United States)

    Wu, Bing-Ruey

    In this work, GaAsSb-based double heterojunction bipolar transistors (DHBTs) and light emitting transistors (LETs) are grown using gas source molecular beam epitaxy (GSMBE). High-speed GaAs0.5Sb0.5/InP DHBTs are developed through the exercise of GSMBE growth optimization, device fabrication, and characterization. By adjusting the growth temperature and V/III flux ratio, the optimal conditions for growing GaAs0.5Sb0.5 base are found to be at high growth temperature and low V/III ratio. The switching sequence is also optimized so that the Sb segregation effect is minimized. By using GaAs0.5Sb0.5-In0.2Ga0.8As 0.7Sb0.3 compositional grading in the base of the GaAsSb/InP DHBT, a significant improvement of fT from 380 GHz to 500 GHz was achieved compared to a uniform GaAs0.5Sb 0.5 DHBT, while maintaining a high breakdown voltage BVCEO ˜ 4V. The cutoff frequency---breakdown voltage product, fT·BVCEO, of over 2000 GHz-V, is the record value for DHBTs of any material system. Incorporating graded InAs-InGaAs emitter contact layer is also shown to effectively reduce the total emitter resistance, further improving the DHBT high speed performance. LET characteristics with quantum wells (QWs) inserted into the base region of GaAsSb/InP DHBTs are also investigated and the preliminary results are presented. An LET with a tensile strained InGaAsSb/GaAs0.65Sb 0.35 DQW in the base was designed and achieved the emission wavelength of ˜1.6 mum, despite of its low light output intensity. The potential and limitation of realizing a transistor laser with an emission wavelength of 1.55 mum using GaAsSb/InP material system will be discussed.

  18. Devices using ballistic transport of two dimensional electron gas in delta doped gallium arsenide high electron mobility transistor structures

    Science.gov (United States)

    Kang, Sungmu

    In this thesis, devices using the ballistic transport of two dimensional electron gas (2DEG) in GaAs High Electron Mobility Transistor(HEMT) structure is fabricated and their dc and ac properties are characterized. This study gives insight on operation and applications of modern submicron devices with ever reduced gate length comparable to electron mean free path. The ballistic transport is achieved using both temporal and spatial limits in this thesis. In temporal limit, when frequency is higher than the scattering frequency (1/(2pitau)), ballistic transport can be achieved. At room temperature, generally the scattering frequency is around 500 GHz but at cryogenic temperature (≤4K) with high mobility GaAs HEMT structure, the frequency is much lower than 2 GHz. On this temporal ballistic transport regime, effect of contact impedance and different dc mobility on device operation is characterized with the ungated 2DEG of HEMT structure. In this ballistic regime, impedance and responsivity of plasma wave detector are investigated using the gated 2DEG of HEMT at different ac boundary conditions. Plasma wave is generated at asymmetric ac boundary conditions of HEMTs, where source is short to ground and drain is open while rf power is applied to gate. The wave velocity can be tuned by gate bias voltage and induced drain to source voltage(Vds ) shows the resonant peak at odd number of fundamental frequency. Quantitative power coupling to plasma wave detector leads to experimental characterization of resonant response of plasma wave detector as a function of frequency. Because plasma wave resonance is not limited by transit time, the physics learned in this study can be directly converted to room temperature terahertz detection by simply reducing gate length(Lgate) to submicron for the terahertz application such as non destructive test, bio medical analysis, homeland security, defense and space. In same HEMT structure, the dc and rf characterization on device is also

  19. Gallium Arsenide

    Science.gov (United States)

    Brozel, Mike

    The history of gallium arsenide is complicated because the technology required to produce GaAs devices has been fraught with problems associated with the material itself and with difficulties in its fabrication. Thus, for many years, GaAs was labelled as "the semiconductor of the future, and it will always be that way." Recently, however, advances in compact-disc (CD) technology, fibre-optic communications and mobile telephony have boosted investment in GaAs research and development. Consequently, there have been advances in materials and fabrication technology and, as a result, GaAs devices now enjoy stable niche markets.

  20. Transistors

    CERN Document Server

    Kendall, E J M

    2013-01-01

    Transistors covers the main thread of transistor development. This book is organized into 2 parts encompassing 19, and starts with an overview of the semi-conductor physics pertinent to the understanding of transistors, as well as features and applications of the point contact devices and junction devices. The subsequent part deals with the modulation of conductance of thin films of conductors by surface charges, the metal-semi conductor, and the semi-conductor triode. These topics are followed by discussions on the nature of the forward current, physical principles in transistor, the hole inj

  1. Spin Injection in Indium Arsenide

    Directory of Open Access Journals (Sweden)

    Mark eJohnson

    2015-08-01

    Full Text Available In a two dimensional electron system (2DES, coherent spin precession of a ballistic spin polarized current, controlled by the Rashba spin orbit interaction, is a remarkable phenomenon that’s been observed only recently. Datta and Das predicted this precession would manifest as an oscillation in the source-drain conductance of the channel in a spin-injected field effect transistor (Spin FET. The indium arsenide single quantum well materials system has proven to be ideal for experimental confirmation. The 2DES carriers have high mobility, low sheet resistance, and high spin orbit interaction. Techniques for electrical injection and detection of spin polarized carriers were developed over the last two decades. Adapting the proposed Spin FET to the Johnson-Silsbee nonlocal geometry was a key to the first experimental demonstration of gate voltage controlled coherent spin precession. More recently, a new technique measured the oscillation as a function of channel length. This article gives an overview of the experimental phenomenology of the spin injection technique. We then review details of the application of the technique to InAs single quantum well (SQW devices. The effective magnetic field associated with Rashba spin-orbit coupling is described, and a heuristic model of coherent spin precession is presented. The two successful empirical demonstrations of the Datta Das conductance oscillation are then described and discussed.

  2. Long-Term Characterization of 6H-SiC Transistor Integrated Circuit Technology Operating at 500 C

    Science.gov (United States)

    Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Chang, Carl W.; Beheim, Glenn M.; Okojie, Robert S.; Evans, Laura J.; Meredith Roger D.; Ferrier, Terry L.; Krasowski, Michael J.; Prokop, Norman F.

    2008-01-01

    NASA has been developing very high temperature semiconductor integrated circuits for use in the hot sections of aircraft engines and for Venus exploration. This paper reports on long-term 500 C electrical operation of prototype 6H-SiC integrated circuits based on epitaxial 6H-SiC junction field effect transistors (JFETs). As of this writing, some devices have surpassed 4000 hours of continuous 500 C electrical operation in oxidizing air atmosphere with minimal change in relevant electrical parameters.

  3. Indentation fracture of gallium arsenide

    OpenAIRE

    Pouvreau, Cédric; GIOVANOLA, Jacques; Breguet, Jean-Marc

    2008-01-01

    The scribe and break technique (or dicing) is a widely employed method in the industry of semiconductors to separate infrared laser diodes made from gallium arsenide (GaAs). The scribing step allows to create a precursor crack which is then propagated during the breaking step, along preferential {110} cleavage planes of GaAs. The main drawback of the scribing process is that it generates a lot of undesirable cracks and particles that degrade the performances of devices. In this dissertation, ...

  4. Electrochemically-Gated Field-Effect Transistor with Indium Tin Oxide Nanoparticles as Active Layer

    International Nuclear Information System (INIS)

    An electrochemically-gated junction field-effect transistor with metallic conducting indium tin oxide nanoparticle array as active layer is reported. Fabrication of a field-effect device with a degenerative semiconductor like indium tin oxide (carrier concentration 1020-1021 cm-3) is possible by exploiting the high surface-to-volume ratio of nanoparticles and high surface charge density achievable by electrochemical gating. The on/off ratio obtained is 325 although the applied potential was restricted to the capacitive double layer region (to ensure high repeatability) without allowing redox reactions to take place at the interface. (authors)

  5. Window structure for passivating solar cells based on gallium arsenide

    Science.gov (United States)

    Barnett, Allen M. (Inventor)

    1985-01-01

    Passivated gallium arsenide solar photovoltaic cells with high resistance to moisture and oxygen are provided by means of a gallium arsenide phosphide window graded through its thickness from arsenic rich to phosphorus rich.

  6. Radiation effect on silicon transistors in mixed neutrons–gamma environment

    International Nuclear Information System (INIS)

    The effects of gamma and neutron irradiations on two different types of transistors, Junction Field Effect Transistor (JFET) and Bipolar Junction Transistor (BJT), were investigated. Irradiation was performed using a Syrian research reactor (RR) (Miniature Neutron Source Reactor (MNSR)) and a gamma source (Co-60 cell). For RR irradiation, MCNP code was used to calculate the absorbed dose received by the transistors. The experimental results showed an overall decrease in the gain factors of the transistors after irradiation, and the JFETs were more resistant to the effects of radiation than BJTs. The effect of RR irradiation was also greater than that of gamma source for the same dose, which could be because neutrons could cause more damage than gamma irradiation. - Highlights: • We measure the gain degradation after irradiation of BJT and JFET transistors. • We model the reactor and transistors in order to calculate irradiation dose. • The gain degradation was higher in BJT than in JFET. • Neutrons and gamma dose contributions of reactor were 2% and 98%, respectively. • The highest neutron contribution comes from the fast and resonance absorption neutrons

  7. Transistor data book

    International Nuclear Information System (INIS)

    It introduces how to use this book. It lists transistor data and index, which are Type No, Cross index, Germanium PNP low power transistors, silicon NPN low power transistors, Germanium PNP high power transistors, Switching transistors, transistor arrays, Miscellaneous transistors, types with U.S military specifications, direct replacement transistors, suggested replacement transistors, schematic drawings, outline drawings, device number keys and manufacturer's logos.

  8. Homo-junction ferroelectric field-effect-transistor memory device using solution-processed lithium-doped zinc oxide thin films

    KAUST Repository

    Nayak, Pradipta K.

    2012-06-22

    High performance homo-junction field-effect transistor memory devices were prepared using solution processed transparent lithium-doped zinc oxide thin films for both the ferroelectric and semiconducting active layers. A highest field-effect mobility of 8.7 cm2/Vs was obtained along with an Ion/Ioff ratio of 106. The ferroelectric thin filmtransistors showed a low sub-threshold swing value of 0.19 V/dec and a significantly reduced device operating voltage (±4 V) compared to the reported hetero-junction ferroelectrictransistors, which is very promising for low-power non-volatile memory applications.

  9. Carbon doping of gallium arsenide and reflectance difference spectroscopy of compound semiconductors grown by metalorganic vapor-phase epitaxy

    Science.gov (United States)

    Begarney, Michael John

    The surface structure and chemistry of compound semiconductors used in heterojunction bipolar transistors was investigated. Lattice-matched, single crystal films of gallium arsenide and indium phosphide were deposited by metalorganic vapor-phase epitaxy in a horizontal-flow, quartz reactor. Two areas of the transistor fabrication process were studied: (1) carbon doping of the gallium arsenide base layer using carbon tetrachloride, and (2) in-situ monitoring of the surface reconstructions of gallium arsenide and indium phosphide by reflectance difference spectroscopy for improved heterointerface formation. Carbon tetrachloride was found to effect the growth of gallium arsenide in two ways: (1) reaction of chlorine with adsorbed gallium atoms to produce volatile GaCl, and (2) reaction of chlorine with the GaAs film to produce GaCl3. The latter of these reactions was found to be insignificant below a temperature-dependent threshold ratio of chlorine to gallium. At lower values of this ratio, step bunching and pinning was observed, while at higher values, pits ranging from 20 to 50 nm in diameter resulted. We show that these results arise due to the presence of the c(4 x 4) gallium arsenide reconstruction during crystal growth, and the site-specific adsorption of CCl4 at gallium atom sites, which are present only at step edges for this reconstruction. The relationship between the reflectance difference spectra and the atomic structure of arsenic-rich reconstructions of GaAs (001) were investigated. It was found that a roughening process, involving the desorption of arsenic and outdiffusion of gallium atoms to the surface, takes place as the surface structure changes with decreasing arsenic coverage. We determined that the intensity of the negative peak at 2.8 eV strongly depends on the presence of adsorbed alkyl groups and gallium atoms, while, by contrast, the intensity of the positive peak at 2.9 eV is directly proportional to the density of (2 x 4)-type dimers. We

  10. Thin Films of Gallium Arsenide and Gallium Aluminum Arsenide by Metalorganic Chemical Vapor Deposition.

    Science.gov (United States)

    Look, Edward Gene Lun

    Low pressure metalorganic chemical vapor deposition (LPMOCVD) of thin films of gallium arsenide (GaAs) and gallium aluminum arsenide (GaAlAs) was performed in a horizontal cold wall chemical vapor deposition (CVD) reactor. The organometallic (group III) sources were triethylgallium (TEGa) and triethylaluminum (TEAl), used in conjunction with arsine (AsH_3) as the group V source. It was found that growth parameters such as growth temperature, pressure, source flow rates and temperatures have a profound effect on the film quality and composition. Depending on the particular combination of conditions, both the surface and overall morphologies may be affected. The films were nondestructively analyzed by Raman and photoreflectance spectroscopies, x-ray diffraction and rocking curve studies, scanning electron microscopy, energy dispersive spectroscopy, Hall measurements and film thicknesses were determined with a step profilometer.

  11. Transistor Effect in Improperly Connected Transistors.

    Science.gov (United States)

    Luzader, Stephen; Sanchez-Velasco, Eduardo

    1996-01-01

    Discusses the differences between the standard representation and a realistic representation of a transistor. Presents an experiment that helps clarify the explanation of the transistor effect and shows why transistors should be connected properly. (JRH)

  12. A terminal molybdenum arsenide complex synthesized from yellow arsenic.

    Science.gov (United States)

    Curley, John J; Piro, Nicholas A; Cummins, Christopher C

    2009-10-19

    A terminal molybdenum arsenide complex is synthesized in one step from the reactive As(4) molecule. The properties of this complex with its arsenic atom ligand are discussed in relation to the analogous nitride and phosphide complexes. PMID:19764796

  13. Investigation of Epitaxial Lift-Off Gallium Arsenide and Langmuir-Blodgett Films for Optoelectronic Device Applications

    Science.gov (United States)

    Shah, Divyang Manharlal

    Epitaxial lift-off (ELO), a technique of removing an epitaxially grown GaAs layer from its growth substrate by selective etching of an AlAs sacrificial layer, is described for field-effect transistor fabrication independent of the GaAs growth substrate. Metal Semiconductor Field-Effect Transistors (MESFETs) and High Electron Mobility Transistors (HEMTs) fabricated on silicon and sapphire substrates using ELO are investigated. A 0.1 μm gate length depletion mode MESFET made on silicon exhibited a unity current gain frequency f_{ rm t} = 34 GHz. Excellent device isolation with subpicoampere leakage currents is obtained. A high input impedance amplifier has been implemented on silicon substrate using ELO GaAs MESFETs. The amplifier had an input RC time constant limited bandwidth of 500 MHz. Results of investigation of a novel source of cadmium and zinc diffusion for shallow p^ {+}-n junction fabrication in In _{0.53}Ga_{0.47 }As/InP are also presented. Langmuir-Blodgett (LB) deposited monolayers of Cadmium and Zinc arachidate have been used as a source of Cd and Zn dopants in InGaAs/InP. This new source provides precise control of the dopant dose through the number of LB film monolayers deposited and it is also a safer method of handling toxic Cd. The LB film can be patterned by lift-off for a patterned diffusion without a mask. Highly doped (N_{ rm a}= 2-4 times 10^{19} cm^ {-3}), shallow (0.1-0.4 mu m) p^{+}-n junctions have been obtained. Junction field-effect transistors (JFETs) and PIN photodetectors have been fabricated as a demonstration of the usefulness of the technique. A PIN photodetector had a 100 pA dark current at -5 V DC bias and a bandwidth of 2 GHz. A new technique for fabricating optoelectronic integrated circuit (OEIC) photoreceivers for 1.3-1.55 μm wavelength optical communication has also been proposed. The proposed OEIC uses ELO GaAs MESFETs and InGaAs/InP PIN photodetectors.

  14. Gallium arsenide p-type low temperature thermometers

    International Nuclear Information System (INIS)

    The use of p-type gallium arsenide for resistance thermometry is discussed. This semiconductor can be used for creating a family of thermometers with sufficiently small magnetoresistance and high sensitivity for the 0.3 - 350 K range. Performance characteristics of gallium arsenide doped with zinc, cadmium and manganese in the 1016 - 1018 cm-3 range of concentration and magnetoresistance in fields of up to 5T are examined. (author)

  15. Maskless proton beam writing in gallium arsenide

    International Nuclear Information System (INIS)

    Proton beam writing (PBW) is a direct write technique that employs a focused MeV proton beam which is scanned in a pre-determined pattern over a target material which is subsequently electrochemically etched or chemically developed. By changing the energy of the protons the range of the protons can be changed. The ultimate depth of the structure is determined by the range of the protons in the material and this allows structures to be formed to different depths. PBW has been successfully employed on etchable glasses, polymers and semiconductor materials such as silicon (Si) and gallium arsenide (GaAs). This study reports on PBW in p-type GaAs and compares experimental results with computer simulations using the Atlas (copy right) semiconductor device package from SILVACO. It has already been proven that hole transport is required for the electrochemical etching of GaAs using Tiron (4,5-dihydroxy-m-benzenedisulfonic acid, di-sodium salt). PBW in GaAs results in carrier removal in the irradiated regions and consequently minimal hole transport (in these regions) during electrochemical etching. As a result the irradiated regions are significantly more etch resistant than the non-irradiated regions. This allows high aspect ratio structures to be formed

  16. Maskless proton beam writing in gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Mistry, P. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom) and Nano-Electronics Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom)]. E-mail: p.mistry@surrey.ac.uk; Gomez-Morilla, I. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Smith, R.C. [Nano-Electronics Centre, Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom); Thomson, D. [Advanced Technology Institute, University of Surrey, Guildford GU2 7XH (United Kingdom); Grime, G.W. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Webb, R.P. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Gwilliam, R. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Jeynes, C. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Cansell, A. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Merchant, M. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom); Kirkby, K.J. [Ion Beam Centre, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2007-07-15

    Proton beam writing (PBW) is a direct write technique that employs a focused MeV proton beam which is scanned in a pre-determined pattern over a target material which is subsequently electrochemically etched or chemically developed. By changing the energy of the protons the range of the protons can be changed. The ultimate depth of the structure is determined by the range of the protons in the material and this allows structures to be formed to different depths. PBW has been successfully employed on etchable glasses, polymers and semiconductor materials such as silicon (Si) and gallium arsenide (GaAs). This study reports on PBW in p-type GaAs and compares experimental results with computer simulations using the Atlas (copy right) semiconductor device package from SILVACO. It has already been proven that hole transport is required for the electrochemical etching of GaAs using Tiron (4,5-dihydroxy-m-benzenedisulfonic acid, di-sodium salt). PBW in GaAs results in carrier removal in the irradiated regions and consequently minimal hole transport (in these regions) during electrochemical etching. As a result the irradiated regions are significantly more etch resistant than the non-irradiated regions. This allows high aspect ratio structures to be formed.

  17. Inhalation developmental toxicology studies: Gallium arsenide in mice and rats

    Energy Technology Data Exchange (ETDEWEB)

    Mast, T.J.; Greenspan, B.J.; Dill, J.A.; Stoney, K.H.; Evanoff, J.J.; Rommereim, R.L.

    1990-12-01

    Gallium arsenide is a crystalline compound used extensively in the semiconductor industry. Workers preparing solar cells and gallium arsenide ingots and wafers are potentially at risk from the inhalation of gallium arsenide dust. The potential for gallium arsenide to cause developmental toxicity was assessed in Sprague- Dawley rats and CD-1 (Swiss) mice exposed to 0, 10, 37, or 75 mg/m{sup 3} gallium arsenide, 6 h/day, 7 days/week. Each of the four treatment groups consisted of 10 virgin females (for comparison), and {approx}30 positively mated rats or {approx}24 positively mated mice. Mice were exposed on 4--17 days of gestation (dg), and rats on 4--19 dg. The day of plug or sperm detection was designated as 0 dg. Body weights were obtained throughout the study period, and uterine and fetal body weights were obtained at sacrifice (rats, 20 dg; mice, 18 dg). Implants were enumerated and their status recorded. Live fetuses were sexed and examined for gross, visceral, skeletal, and soft-tissue craniofacial defects. Gallium and arsenic concentrations were determined in the maternal blood and uterine contents of the rats (3/group) at 7, 14, and 20 dg. 37 refs., 11 figs., 30 tabs.

  18. 6H-SiC Transistor Integrated Circuits Demonstrating Prolonged Operation at 500 C

    Science.gov (United States)

    Neudeck, Philip G.; Spry, David J.; Chen, Liang-Yu; Chang, Carl W.; Beheim, Glenn M.; Okojie, Robert S.; Evans, Laura J.; Meredith, Roger; Ferrier, Terry; Krasowski, Michael J.; Prokop, Norman F.

    2008-01-01

    The NASA Glenn Research Center is developing very high temperature semiconductor integrated circuits (ICs) for use in the hot sections of aircraft engines and for Venus exploration where ambient temperatures are well above the approximately 300 degrees Centigrade effective limit of silicon-on-insulator IC technology. In order for beneficial technology insertion to occur, such transistor ICs must be capable of prolonged operation in such harsh environments. This paper reports on the fabrication and long-term 500 degrees Centigrade operation of 6H-SiC integrated circuits based on epitaxial 6H-SiC junction field effect transistors (JFETs). Simple analog amplifier and digital logic gate ICs have now demonstrated thousands of hours of continuous 500 degrees Centigrade operation in oxidizing air atmosphere with minimal changes in relevant electrical parameters. Electrical characterization and modeling of transistors and circuits at temperatures from 24 degrees Centigrade to 500 degrees Centigrade is also described. Desired analog and digital IC functionality spanning this temperature range was demonstrated without changing the input signals or power supply voltages.

  19. Superconducting transistor

    Science.gov (United States)

    Gray, Kenneth E.

    1979-01-01

    A superconducting transistor is formed by disposing three thin films of superconducting material in a planar parallel arrangement and insulating the films from each other by layers of insulating oxides to form two tunnel junctions. One junction is biased above twice the superconducting energy gap and the other is biased at less than twice the superconducting energy gap. Injection of quasiparticles into the center film by one junction provides a current gain in the second junction.

  20. Metal Insulator Semiconductor Structures on Gallium Arsenide.

    Science.gov (United States)

    Connor, Sean Denis

    Available from UMI in association with The British Library. The compound semiconductor gallium arsenide and its associated aluminium alloys have been the subject of intensive research in recent years. These materials offer the advantage of high electron mobilities coupled with the ability to be 'barrier engineered' leading to high injection efficiencies in bipolar devices. From a technological viewpoint however these materials are difficult to work with and device realisation is a major problem. Both thermal and anodic oxidation of these materials fail to produce a dielectric of sufficient quality for device applications and as a result devices tend to be complex non planar, mesa structures. A technique is proposed whereby the electrical interface is separated from the dielectric by means of a thin layer of AlGaAs, carrier confinement in the active GaAs region being maintained by the potential barriers to holes and electrons formed by the GaAs-AlGaAs junction. The integrity of these barriers is maintained by the provision of a suitable 'capping' dielectric. The electrical characteristics of various dielectric systems on GaAs have been investigated by means of current -voltage, capacitance-voltage and electronic breakdown measurements. Transport mechanisms for leakage current through these systems are identified and the interface properties (viz Fermi level pinning etc.) assessed by means of a direct comparison between experimental capacitance-voltage curves and theoretical data obtained from classical theory. As a technique for producing a convenient, in house 'capping' dielectric with good electrical and mechanical properties, the plasma anodisation of deposited aluminium films has been investigated. The anodisation parameters have been optimised for oxidation of these films in a microwave sustained oxygen plasma to give alumina films of around 500 A. A qualitative model for the anodisation process, involving linear and parabolic growth kinetics is proposed and

  1. Transport-reaction model for defect and carrier behavior within displacement cascades in gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Wampler, William R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Myers, Samuel M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2014-02-01

    A model is presented for recombination of charge carriers at displacement damage in gallium arsenide, which includes clustering of the defects in atomic displacement cascades produced by neutron or ion irradiation. The carrier recombination model is based on an atomistic description of capture and emission of carriers by the defects with time evolution resulting from the migration and reaction of the defects. The physics and equations on which the model is based are presented, along with details of the numerical methods used for their solution. The model uses a continuum description of diffusion, field-drift and reaction of carriers and defects within a representative spherically symmetric cluster. The initial radial defect profiles within the cluster were chosen through pair-correlation-function analysis of the spatial distribution of defects obtained from the binary-collision code MARLOWE, using recoil energies for fission neutrons. Charging of the defects can produce high electric fields within the cluster which may influence transport and reaction of carriers and defects, and which may enhance carrier recombination through band-to-trap tunneling. Properties of the defects are discussed and values for their parameters are given, many of which were obtained from density functional theory. The model provides a basis for predicting the transient response of III-V heterojunction bipolar transistors to pulsed neutron irradiation.

  2. On the understanding of irradiation effects in germanium, silicon and gallium arsenide semi-conductors

    International Nuclear Information System (INIS)

    We have studied the behaviour of germanium, silicon and gallium arsenide semiconductors irradiated by different projectiles (heavy ions, protons, electrons and fullerenes). At low doses, thanks to deep level transient spectroscopy (DLTS) and Hall effect electrical measurements, we were able to explicit the nature of the defects present in germanium after irradiation at room temperature. For different projectiles, we have determined the defect creation kinetics. At higher doses, the electrical measurements have brought to the fore the presence of a specific defect created only after an heavy ion (or proton) irradiation. Moreover, positron annihilation spectroscopy (PAS) measurements show that size of this specific defect increases with the fluence. The damage has also been quantified by channeling Rutherford backscaterring (RBS-C) measurements. At first sight, the obtained defect creation rates are normalized by the nuclear collisions. This normalization is also present in the inverse of the gain evolution in silicon bipolar transistors. Meanwhile, an extensive study shows an efficiency decrease of the defect creation at intermediate values of the electronic energy loss Se, then, at the opposite, an increasing at higher values of Se. In the three semiconductors, we have observed track formation after fullerenes irradiation. These tracks are amorphous cylinders which have been characterized by transmission and high resolution electronic microscopy. They are due to the very high values of the electronic energy density which can be deposited by fullerenes owing to their low velocity. (author)

  3. T-shaped emitter metal heterojunction bipolar transistors for submillimeter wave applications

    Science.gov (United States)

    Fung, Andy; Samoska, Lorene; Velebir, Jim; Siege, Peter; Rodwell, Mark; Paidi, Vamsi; Griffth, Zach; Urteaga, Miguel; Malik, Roger

    2004-01-01

    We report on the development of submillimeter wave transistors at JPL. The goal of the effort is to produce advance-reliable high frequency and high power amplifiers, voltage controlled oscillators, active multipliers, and high-speed mixed-signal circuits for space borne applications. The technology in development to achieve this is based on the Indium Phosphide (InP) Heterojunction Bipolar Transistor (HBT). The HBT is well suited for high speed, high power and uniform (across wafer) performance, due to the ability to tailor the material structure that electrons traverse through by well-controlled epitaxial growth methods. InP with its compatible lattice matched alloys such as indium gallium arsenide (InGaAs) and indium aluminium arsenide (InAlAs) provides for high electron velocities and high voltage breakdown capabilities. The epitaxial methods for this material system are fairly mature, however the implementation of high performance and reliable transistors are still under development by many laboratories. Our most recently fabricated, second generation mesa HBTs at JPL have extrapolated current gain cutoff frequency (FJ of 142GHz and power gain cutoff frequency (Fm,) of approximately 160GHz. This represents a 13% and 33% improvement of Ft and F, respectively, compared to the first generation mesa HBTs [l]. Analysis based on the University of California, Santa Barbara (UCSB) device model, RF device characteristics can be significantly improved by reducing base contact resistance and base metal contact width. We will describe our effort towards increasing transistor performance and yield.

  4. Comparison of 6 Diode and 6 Transistor Mixers Based on Analysis and Measurement

    Directory of Open Access Journals (Sweden)

    J. Ladvánszky

    2016-01-01

    Full Text Available Our goal is to overview semiconductor mixers designed for good large signal performance. Twelve different mixers were compared utilizing pn diodes, bipolar transistors, and/or junction field effect transistors. The main aspect of comparison is the third-order intercept point (IP3, and both circuit analysis and measurement results have been considered. IP3 has been analyzed by the program AWR (NI AWR Design Environment and measured by two-tone test (Keysight Technologies. We provide three ways of improvement of large signal performance: application of a diplexer at the RF port, reduction of DC currents, and exploiting a region of RF input power with infinite IP3. In addition to that, our contributions are several modifications of existing mixers and a new mixer circuit (as illustrated in the figures. It is widely believed that the slope of the third-order intermodulation product versus input power is always greater than that of the first-order product. However, measurement and analysis revealed (as illustrated in the figures that the two lines may be parallel over a broad range of input power, thus resulting in infinite IP3. Mixer knowledge may be useful for a wide range of readers because almost every radio contains at least one mixer.

  5. Manifestation of the long-range action effect in ion-irradiated transistor structures based on GaAs

    International Nuclear Information System (INIS)

    The effect of ion irradiation on the parameters of the field transistors active layers with the Schottky barrier produced on the basis of the epitaxial gallium arsenide is studied. The transistors were irradiated by the argon ions with the energy of 90 eV with different doses and current densities. The change in the electron concentration and mobility is determined when current densities of argon ions are above 0.5 μA/cm2 and doses are above 5 x 1015 cm-2 . Besides, the more sharper profile of the electron concentration distribution is formed in the depth of the active layer near the interface boundary with the buffer

  6. Gallium interstitial contributions to diffusion in gallium arsenide

    OpenAIRE

    Schick, J. T.; Morgan, C. G.; Papoulias, P

    2011-01-01

    Enthalpies of formation of gallium interstitials and all the other native point defects in gallium arsenide are calculated using the same well-converged \\emph{ab initio} techniques. Using these results, equilibrium concentrations of these defects are computed as a function of chemical potential from the arsenic rich limit to the gallium rich limit and as a function of the doping level from $p$-type to $n$-type. Gallium interstitial diffusion paths and migration barriers for diffusion are dete...

  7. Plasma chemical etching of gallium arsenide in chlorine

    International Nuclear Information System (INIS)

    One of the most promising methods, used for the examination of the kinetics and determination of the moments of the start and completion of the processes of plasma chemical etching of a wide range of inorganic materials is optical emission spectroscopy. Therefore, the aim of this work was to examine the kinetic relationships of etching of gallium arsenide in chlorine plasma and determine the possibilities of the optical emission spectroscopy for examination and control of the process

  8. STABILIZED TRANSISTOR AMPLIFIER

    Science.gov (United States)

    Noe, J.B.

    1963-05-01

    A temperature stabilized transistor amplifier having a pair of transistors coupled in cascade relation that are capable of providing amplification through a temperature range of - 100 un. Concent 85% F to 400 un. Concent 85% F described. The stabilization of the amplifier is attained by coupling a feedback signal taken from the emitter of second transistor at a junction between two serially arranged biasing resistances in the circuit of the emitter of the second transistor to the base of the first transistor. Thus, a change in the emitter current of the second transistor is automatically corrected by the feedback adjustment of the base-emitter potential of the first transistor and by a corresponding change in the base-emitter potential of the second transistor. (AEC)

  9. Size-effects in indium gallium arsenide nanowire field-effect transistors

    Science.gov (United States)

    Zota, Cezar B.; Lind, E.

    2016-08-01

    We fabricate and analyze InGaAs nanowire MOSFETs with channel widths down to 18 nm. Low-temperature measurements reveal quantized conductance due to subband splitting, a characteristic of 1D systems. We relate these features to device performance at room-temperature. In particular, the threshold voltage versus nanowire width is explained by direct observation of quantization of the first sub-band, i.e., band gap widening. An analytical effective mass quantum well model is able to describe the observed band structure. The results reveal a compromise between reliability, i.e., VT variability, and on-current, through the mean free path, in the choice of the channel material.

  10. SiC JFET Transistor Circuit Model for Extreme Temperature Range

    Science.gov (United States)

    Neudeck, Philip G.

    2008-01-01

    A technique for simulating extreme-temperature operation of integrated circuits that incorporate silicon carbide (SiC) junction field-effect transistors (JFETs) has been developed. The technique involves modification of NGSPICE, which is an open-source version of the popular Simulation Program with Integrated Circuit Emphasis (SPICE) general-purpose analog-integrated-circuit-simulating software. NGSPICE in its unmodified form is used for simulating and designing circuits made from silicon-based transistors that operate at or near room temperature. Two rapid modifications of NGSPICE source code enable SiC JFETs to be simulated to 500 C using the well-known Level 1 model for silicon metal oxide semiconductor field-effect transistors (MOSFETs). First, the default value of the MOSFET surface potential must be changed. In the unmodified source code, this parameter has a value of 0.6, which corresponds to slightly more than half the bandgap of silicon. In NGSPICE modified to simulate SiC JFETs, this parameter is changed to a value of 1.6, corresponding to slightly more than half the bandgap of SiC. The second modification consists of changing the temperature dependence of MOSFET transconductance and saturation parameters. The unmodified NGSPICE source code implements a T(sup -1.5) temperature dependence for these parameters. In order to mimic the temperature behavior of experimental SiC JFETs, a T(sup -1.3) temperature dependence must be implemented in the NGSPICE source code. Following these two simple modifications, the Level 1 MOSFET model of the NGSPICE circuit simulation program reasonably approximates the measured high-temperature behavior of experimental SiC JFETs properly operated with zero or reverse bias applied to the gate terminal. Modification of additional silicon parameters in the NGSPICE source code was not necessary to model experimental SiC JFET current-voltage performance across the entire temperature range from 25 to 500 C.

  11. Testing of gallium arsenide solar cells on the CRRES vehicle

    International Nuclear Information System (INIS)

    A flight experiment was designed to determine the optimum design for gallium arsenide (GaAs) solar cell panels in a radiation environment. Elements of the experiment design include, different coverglass material and thicknesses, welded and soldered interconnects, different solar cell efficiencies, different solar cell types, and measurement of annealing properties. This experiment is scheduled to fly on the Combined Release and Radiation Effects Satellite (CRRES). This satellite will simultaneously measure the radiation environment and provide engineering data on solar cell degradation that can be directly related to radiation damage

  12. Liquid phase epitaxy of gallium arsenide - a review

    International Nuclear Information System (INIS)

    Liquid phase epitaxy of gallium arsenide has been investigated intensively from the late 1960's to the present and has now a special place in the manufacture of wide band, compound semiconductor radiation detectors. Although this particular process appears to have gained prominence in the last three decades, the authors point out that its origins reach back to 1836 when Frankenheim made his first observations. A brief review is presented from a semiconductor applications point of view on how this subject developed. 70 refs., 5 figs

  13. Macroscopic diffusion models for precipitation in crystalline gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Kimmerle, Sven-Joachim Wolfgang

    2009-09-21

    Based on a thermodynamically consistent model for precipitation in gallium arsenide crystals including surface tension and bulk stresses by Dreyer and Duderstadt, we propose two different mathematical models to describe the size evolution of liquid droplets in a crystalline solid. The first model treats the diffusion-controlled regime of interface motion, while the second model is concerned with the interface-controlled regime of interface motion. Our models take care of conservation of mass and substance. These models generalise the well-known Mullins- Sekerka model for Ostwald ripening. We concentrate on arsenic-rich liquid spherical droplets in a gallium arsenide crystal. Droplets can shrink or grow with time but the centres of droplets remain fixed. The liquid is assumed to be homogeneous in space. Due to different scales for typical distances between droplets and typical radii of liquid droplets we can derive formally so-called mean field models. For a model in the diffusion-controlled regime we prove this limit by homogenisation techniques under plausible assumptions. These mean field models generalise the Lifshitz-Slyozov-Wagner model, which can be derived from the Mullins-Sekerka model rigorously, and is well understood. Mean field models capture the main properties of our system and are well adapted for numerics and further analysis. We determine possible equilibria and discuss their stability. Numerical evidence suggests in which case which one of the two regimes might be appropriate to the experimental situation. (orig.)

  14. Point defects and electric compensation in gallium arsenide single crystals

    International Nuclear Information System (INIS)

    In the present thesis the point-defect budget of gallium arsenide single crystals with different dopings is studied. It is shown, in which way the concentration of the single point defects depende on the concentration of the dopants, the stoichiometry deviation, and the position of the Fermi level. For this serve the results of the measurement-technical characterization of a large number of samples, in the fabrication of which these parameters were directedly varied. The main topic of this thesis lies in the development of models, which allow a quantitative description of the experimentally studied electrical and optical properties of gallium arsenide single crystals starting from the point-defect concentrations. Because from point defects charge carriers can be set free, their concentration determines essentially the charge-carrier concentration in the bands. In the ionized state point defects act as scattering centers for free charge carriers and influence by this the drift mobility of the charge carriers. A thermodynamic modeling of the point-defect formation yields statements on the equilibrium concentrations of the point defects in dependence on dopant concentration and stoichiometry deviation. It is show that the electrical properties of the crystals observed at room temperature result from the kinetic suppression of processes, via which the adjustment of a thermodynamic equilibrium between the point defects is mediated

  15. SiC Optically Modulated Field-Effect Transistor

    Science.gov (United States)

    Tabib-Azar, Massood

    2009-01-01

    An optically modulated field-effect transistor (OFET) based on a silicon carbide junction field-effect transistor (JFET) is under study as, potentially, a prototype of devices that could be useful for detecting ultraviolet light. The SiC OFET is an experimental device that is one of several devices, including commercial and experimental photodiodes, that were initially evaluated as detectors of ultraviolet light from combustion and that could be incorporated into SiC integrated circuits to be designed to function as combustion sensors. The ultraviolet-detection sensitivity of the photodiodes was found to be less than desired, such that it would be necessary to process their outputs using high-gain amplification circuitry. On the other hand, in principle, the function of the OFET could be characterized as a combination of detection and amplification. In effect, its sensitivity could be considerably greater than that of a photodiode, such that the need for amplification external to the photodetector could be reduced or eliminated. The experimental SiC OFET was made by processes similar to JFET-fabrication processes developed at Glenn Research Center. The gate of the OFET is very long, wide, and thin, relative to the gates of typical prior SiC JFETs. Unlike in prior SiC FETs, the gate is almost completely transparent to near-ultraviolet and visible light. More specifically: The OFET includes a p+ gate layer less than 1/4 m thick, through which photons can be transported efficiently to the p+/p body interface. The gate is relatively long and wide (about 0.5 by 0.5 mm), such that holes generated at the body interface form a depletion layer that modulates the conductivity of the channel between the drain and the source. The exact physical mechanism of modulation of conductivity is a subject of continuing research. It is known that injection of minority charge carriers (in this case, holes) at the interface exerts a strong effect on the channel, resulting in amplification

  16. Enhancement of metal - semiconductor barrier height with superthin silicon dioxide films deposited on gallium arsenide by liquid phase deposition

    International Nuclear Information System (INIS)

    This study presents a method for surface passivation using silicon dioxide (SiO2). The proposed method has shown great effectiveness on metal - semiconductor barrier height enhancement. A high quality SiO2 layer is developed via liquid phase deposition, a method which naturally leaves a doping-level fluorine residue in the SiO2. The addition of fluorine to enhance the Schottky barrier height (SBH) is first discussed. Experimental results are presented. It is found that this fluorine addition enhances the Schottky barrier height, which allows a larger positive gate bias for enhancement mode metal - semiconductor field-effect transistors, thus permitting the fabrication of digital logic circuits with improved noise margins and relaxed tolerance with regard to device threshold voltage uniformity. The SBH to n-gallium arsenide (GaAS) is found to be approximately 0.7 eV. Finally, the effective barrier height of the metal - insulator - semiconductor structure reached 1.03 eV after annealing. The enhancement of SBH has been attributed to the formation of these stable interface layers. A model for fluorine-enhanced SiO2 SBH enhancement is also presented. [copyright] 2001 American Institute of Physics

  17. Methods for forming group III-arsenide-nitride semiconductor materials

    Science.gov (United States)

    Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

    2002-01-01

    Methods are disclosed for forming Group III-arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

  18. Temperature dependence of carrier capture by defects in gallium arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Wampler, William R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Modine, Normand A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-08-01

    This report examines the temperature dependence of the capture rate of carriers by defects in gallium arsenide and compares two previously published theoretical treatments of this based on multi phonon emission (MPE). The objective is to reduce uncertainty in atomistic simulations of gain degradation in III-V HBTs from neutron irradiation. A major source of uncertainty in those simulations is poor knowledge of carrier capture rates, whose values can differ by several orders of magnitude between various defect types. Most of this variation is due to different dependence on temperature, which is closely related to the relaxation of the defect structure that occurs as a result of the change in charge state of the defect. The uncertainty in capture rate can therefore be greatly reduced by better knowledge of the defect relaxation.

  19. Surface-enhanced gallium arsenide photonic resonator with a quality factor of six million

    OpenAIRE

    Guha, Biswarup; Marsault, Felix; Cadiz, Fabian; Morgenroth, Laurence; Ulin, Vladimir; Berkovitz, Vladimir; Lemaître, Aristide; Gomez, Carmen; Amo, Alberto; Combrié, Sylvian; Gérard, Bruno; Leo, Giuseppe; Favero, Ivan

    2016-01-01

    Gallium Arsenide and related compound semiconductors lie at the heart of optoelectronics and integrated laser technologies. Shaped at the micro and nano-scale, they allow strong interaction with quantum dots and quantum wells, and promise to result in stunning devices. However gallium arsenide optical structures presently exhibit lower performances than their silicon-based counterparts, notably in nanophotonics where the surface plays a chief role. Here we report on advanced surface control o...

  20. Silicon nanowire transistors

    CERN Document Server

    Bindal, Ahmet

    2016-01-01

    This book describes the n and p-channel Silicon Nanowire Transistor (SNT) designs with single and dual-work functions, emphasizing low static and dynamic power consumption. The authors describe a process flow for fabrication and generate SPICE models for building various digital and analog circuits. These include an SRAM, a baseband spread spectrum transmitter, a neuron cell and a Field Programmable Gate Array (FPGA) platform in the digital domain, as well as high bandwidth single-stage and operational amplifiers, RF communication circuits in the analog domain, in order to show this technology’s true potential for the next generation VLSI. Describes Silicon Nanowire (SNW) Transistors, as vertically constructed MOS n and p-channel transistors, with low static and dynamic power consumption and small layout footprint; Targets System-on-Chip (SoC) design, supporting very high transistor count (ULSI), minimal power consumption requiring inexpensive substrates for packaging; Enables fabrication of different types...

  1. Vertical organic transistors

    Science.gov (United States)

    Lüssem, Björn; Günther, Alrun; Fischer, Axel; Kasemann, Daniel; Leo, Karl

    2015-11-01

    Organic switching devices such as field effect transistors (OFETs) are a key element of future flexible electronic devices. So far, however, a commercial breakthrough has not been achieved because these devices usually lack in switching speed (e.g. for logic applications) and current density (e.g. for display pixel driving). The limited performance is caused by a combination of comparatively low charge carrier mobilities and the large channel length caused by the need for low-cost structuring. Vertical Organic Transistors are a novel technology that has the potential to overcome these limitations of OFETs. Vertical Organic Transistors allow to scale the channel length of organic transistors into the 100 nm regime without cost intensive structuring techniques. Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies. In this review, these different approaches are compared and recent progress is highlighted.

  2. The Bloch Oscillating Transistor

    OpenAIRE

    Seppä, H.; Hassel, J.

    2003-01-01

    We introduce a new mesoscopic transistor, which consists of a superconducting island connected to superconducting and normal electrodes via two mesoscopic tunnel junctions. Furthermore, the island is being charged through a resistor. The interplay between Bloch oscillations, single-electron effects and ohmic current leads to a device having a high current gain. The operation and characteristics of the transistor are analyzed with a numerical model.

  3. Transistor-based interface circuitry

    Science.gov (United States)

    Taubman, Matthew S.

    2007-02-13

    Among the embodiments of the present invention is an apparatus that includes a transistor, a servo device, and a current source. The servo device is operable to provide a common base mode of operation of the transistor by maintaining an approximately constant voltage level at the transistor base. The current source is operable to provide a bias current to the transistor. A first device provides an input signal to an electrical node positioned between the emitter of the transistor and the current source. A second device receives an output signal from the collector of the transistor.

  4. Noble Metal Arsenides and Gold Inclusions in Northwest Africa 8186

    Science.gov (United States)

    Srinivasan, P.; Agee, C. B.; McCubbin, F. M.; Rahman, Z.; Keller, L. P.

    2016-01-01

    CK carbonaceous chondrites are a highly thermally altered group of carbonaceous chondrites, experiencing temperatures ranging between approx.576-867 C. Additionally, the mineralogy of the CK chondrites record the highest overall oxygen fugacity of all chondrites, above the fayalite-magnetite-quartz (FMQ) buffer. Metallic Fe-Ni is extremely rare in CK chondrites, but magnetite and Fe,Ni sulfides are commonly observed. Noble metal-rich inclusions have previously been found in some magnetite and sulfide grains. These arsenides, tellurides, and sulfides, which contain varying amounts of Pt, Ru, Os, Te, As, Ir, and S, are thought to form either by condensation from a solar gas, or by exsolution during metamorphism on the chondritic parent body. Northwest Africa (NWA) 8186 is a highly metamorphosed CK chondrite. This meteorite is predominately composed of NiO-rich forsteritic olivine (Fo65), with lesser amounts of plagioclase (An52), augite (Fs11Wo49), magnetite (with exsolved titanomagnetite, hercynite, and titanohematite), monosulfide solid solution (with exsolved pentlandite), and the phosphate minerals Cl-apatite and merrillite. This meteorite contains coarse-grained, homogeneous silicates, and has 120deg triple junctions between mineral phases, which indicates a high degree of thermal metamorphism. The presence of NiO-rich olivine, oxides phases all bearing Fe3+, and the absence of metal, are consistent with an oxygen fugacity above the FMQ buffer. We also observed noble metal-rich phases within sulfide grains in NWA 8186, which are the primary focus of the present study.

  5. Diode, transistor & fet circuits manual

    CERN Document Server

    Marston, R M

    2013-01-01

    Diode, Transistor and FET Circuits Manual is a handbook of circuits based on discrete semiconductor components such as diodes, transistors, and FETS. The book also includes diagrams and practical circuits. The book describes basic and special diode characteristics, heat wave-rectifier circuits, transformers, filter capacitors, and rectifier ratings. The text also presents practical applications of associated devices, for example, zeners, varicaps, photodiodes, or LEDs, as well as it describes bipolar transistor characteristics. The transistor can be used in three basic amplifier configuration

  6. Quantum thermal transistor

    CERN Document Server

    Joulain, Karl; Ezzahri, Younès; Ordonez-Miranda, Jose

    2016-01-01

    We demonstrate that a thermal transistor can be made up with a quantum system of 3 interacting subsystems , coupled to a thermal reservoir each. This thermal transistor is analogous to an electronic bipolar one with the ability to control the thermal currents at the collector and at the emitter with the imposed thermal current at the base. This is achieved determining the heat fluxes by means of the strong-coupling formalism. For the case of 3 interacting spins, in which one of them is coupled to the other 2, that are not directly coupled, it is shown that high amplification can be obtained in a wide range of energy parameters and temperatures. The proposed quantum transistor could, in principle, be used to develop devices such as a thermal modulator and a thermal amplifier in nano systems.

  7. The comparison between gallium arsenide and indium gallium arsenide as materials for solar cell performance using Silvaco application

    Energy Technology Data Exchange (ETDEWEB)

    Zahari, Suhaila Mohd; Norizan, Mohd Natashah; Mohamad, Ili Salwani; Osman, Rozana Aina Maulat; Taking, Sanna [School of Microelectronic Engineering, Universiti Malaysia Perlis, Kampus Pauh Putra, 02600 Arau, Perlis (Malaysia)

    2015-05-15

    The work presented in this paper is about the development of single and multilayer solar cells using GaAs and InGaAs in AM1.5 condition. The study includes the modeling structure and simulation of the device using Silvaco applications. The performance in term of efficiency of Indium Gallium Arsenide (InGaAs) and GaAs material was studied by modification of the doping concentration and thickness of material in solar cells. The efficiency of the GaAs solar cell was higher than InGaAs solar cell for single layer solar cell. Single layer GaAs achieved an efficiency about 25% compared to InGaAs which is only 2.65% of efficiency. For multilayer which includes both GaAs and InGaAs, the output power, P{sub max} was 8.91nW/cm² with the efficiency only 8.51%. GaAs is one of the best materials to be used in solar cell as a based compared to InGaAs.

  8. Surface-enhanced gallium arsenide photonic resonator with a quality factor of six million

    CERN Document Server

    Guha, Biswarup; Cadiz, Fabian; Morgenroth, Laurence; Ulin, Vladimir; Berkovitz, Vladimir; Lemaître, Aristide; Gomez, Carmen; Amo, Alberto; Combrié, Sylvian; Gérard, Bruno; Leo, Giuseppe; Favero, Ivan

    2016-01-01

    Gallium Arsenide and related compound semiconductors lie at the heart of optoelectronics and integrated laser technologies. Shaped at the micro and nano-scale, they allow strong interaction with quantum dots and quantum wells, and promise to result in stunning devices. However gallium arsenide optical structures presently exhibit lower performances than their silicon-based counterparts, notably in nanophotonics where the surface plays a chief role. Here we report on advanced surface control of miniature gallium arsenide optical resonators, using two distinct techniques that produce permanent results. One leads to extend the lifetime of free-carriers and enhance luminescence, while the other strongly reduces surface absorption originating from mid-gap states and enables ultra-low optical dissipation devices. With such surface control, the quality factor of wavelength-sized optical disk resonators is observed to rise up to six million at telecom wavelength, greatly surpassing previous realizations and opening n...

  9. A Silicon Optical Transistor

    CERN Document Server

    Varghese, Leo T; Wang, Jian; Gan, Fuwan; Niu, Ben; Xuan, Yi; Weiner, Andrew M; Qi, Minghao

    2012-01-01

    A fundamental road block for all-optical information processing is the difficulty in realizing a silicon optical transistor with the ability to provide optical gain, input output isolation and buffer action. In this work, we demonstrate an all-optical transistor using optical nonlinearity in microrings. By using weak light to control strong light, we observed an On/Off ratio up to 20 dB. It can compensate losses in other optical devices and provide fan-out capability. The device is ultra compact and is compatible with current complementary metal-oxide-semiconductor (CMOS) processing.

  10. A Silicon Optical Transistor

    OpenAIRE

    Varghese, Leo T.; Fan, Li; WANG, Jian; Gan, Fuwan; Niu, Ben; Xuan, Yi; Weiner, Andrew M.; Qi, Minghao

    2012-01-01

    A fundamental road block for all-optical information processing is the difficulty in realizing a silicon optical transistor with the ability to provide optical gain, input output isolation and buffer action. In this work, we demonstrate an all-optical transistor using optical nonlinearity in microrings. By using weak light to control strong light, we observed an On/Off ratio up to 20 dB. It can compensate losses in other optical devices and provide fan-out capability. The device is ultra comp...

  11. Mesoscopic photon heat transistor

    DEFF Research Database (Denmark)

    Ojanen, T.; Jauho, Antti-Pekka

    2008-01-01

    We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-typ......We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir...

  12. Progress to a Gallium-Arsenide Deep-Center Laser

    Directory of Open Access Journals (Sweden)

    Janet L. Pan

    2009-10-01

    Full Text Available Although photoluminescence from gallium-arsenide (GaAs deep-centers was first observed in the 1960s, semiconductor lasers have always utilized conduction-to-valence-band transitions. Here we review recent materials studies leading to the first GaAs deep-center laser. First, we summarize well-known properties: nature of deep-center complexes, Franck-Condon effect, hotoluminescence. Second, we describe our recent work: insensitivity of photoluminescence with heating, striking differences between electroluminescence and photoluminescence, correlation between transitions to deep-states and absence of bandgap-emission. Room-temperature stimulated-emission from GaAs deep-centers was observed at low electrical injection, and could be tuned from the bandgap to half-the-bandgap (900–1,600 nm by changing the electrical injection. The first GaAs deep-center laser was demonstrated with electrical injection, and exhibited a threshold of less than 27 mA/cm2 in continuous-wave mode at room temperature at the important 1.54 μm fiber-optic wavelength. This small injection for laser action was explained by fast depopulation of the lower state of the optical transition (fast capture of free holes onto deep-centers, which maintains the population inversion. The evidence for laser action included: superlinear L-I curve, quasi-Fermi level separations satisfying Bernard-Duraffourg’s criterion, optical gains larger than known significant losses, clamping of the optical-emission from lossy modes unable to reach laser action, pinning of the population distribution during laser action.

  13. Greyscale proton beam writing in p-type Gallium Arsenide

    Energy Technology Data Exchange (ETDEWEB)

    Diering, D., E-mail: david.diering@gmx.de [Universität Leipzig, Institute for Experimental Physics II, Division of Nuclear Solid State Physics, Linnéstr. 5, 04103 Leipzig (Germany); Spemann, D., E-mail: spemann@uni-leipzig.de [Universität Leipzig, Institute for Experimental Physics II, Division of Nuclear Solid State Physics, Linnéstr. 5, 04103 Leipzig (Germany); Lenzner, J.; Müller, St.; Böntgen, T.; Wenckstern, H. von [Universität Leipzig, Institute for Experimental Physics II, Semiconductor Physics Group, Linnéstr. 5, 04103 Leipzig (Germany)

    2013-07-01

    Proton beam writing (PBW) is a well known method for micromachining, e.g. of semiconductors. Up to now, only few indication is given on how the resulting structure height in micromachined semiconductors can be controlled by means of fluence variation. This approach for 3D-microstructuring, called Greyscale PBW, was already successfully demonstrated for negative photoresists. In this study (1 0 0) p-type Gallium Arsenide (GaAs) was irradiated with 2.28 MeV protons and fluences in the range from 1.2×10{sup 14} H{sup +} cm{sup −2} to 1.0×10{sup 18} H{sup +} cm{sup −2} at the ion beam laboratory LIPSION and subsequently electrochemically etched with 10%-KOH. A linear dependency of structure height on ion fluence was established. In this way, pyramid-like structures as well as concave-shaped structures could be created. GaAs showed a lateral anisotropic etch behaviour during the development step with preferential etching along the [0 1 1] directions. On some structures the surface roughness and the change of conductivity were investigated by atomic force and scanning capacitance microscopy, respectively. The rms roughness of the surface of the structures was 5.4 nm and 10.6 nm for a fluence of 7.8×10{sup 15} H{sup +} cm{sup −2} and 1.2×10{sup 17} H{sup +} cm{sup −2}, respectively. We observed an increasing etching rate for fluences larger than 10{sup 16} H{sup +} cm{sup −2}.

  14. Indium Phosphide Window Layers for Indium Gallium Arsenide Solar Cells

    Science.gov (United States)

    Jain, Raj K.

    2005-01-01

    Window layers help in reducing the surface recombination at the emitter surface of the solar cells resulting in significant improvement in energy conversion efficiency. Indium gallium arsenide (In(x)Ga(1-x)As) and related materials based solar cells are quite promising for photovoltaic and thermophotovoltaic applications. The flexibility of the change in the bandgap energy and the growth of InGaAs on different substrates make this material very attractive for multi-bandgap energy, multi-junction solar cell approaches. The high efficiency and better radiation performance of the solar cell structures based on InGaAs make them suitable for space power applications. This work investigates the suitability of indium phosphide (InP) window layers for lattice-matched In(0.53)Ga(0.47)As (bandgap energy 0.74 eV) solar cells. We present the first data on the effects of the p-type InP window layer on p-on-n lattice-matched InGaAs solar cells. The modeled quantum efficiency results show a significant improvement in the blue region with the InP window. The bare InGaAs solar cell performance suffers due to high surface recombination velocity (10(exp 7) cm/s). The large band discontinuity at the InP/InGaAs heterojunction offers a great potential barrier to minority carriers. The calculated results demonstrate that the InP window layer effectively passivates the solar cell front surface, hence resulting in reduced surface recombination and therefore, significantly improving the performance of the InGaAs solar cell.

  15. Noble Metal Arsenides and Gold Inclusions in Northwest Africa 8186

    Science.gov (United States)

    Srinivasan, P.; McCubbin, F. M.; Rahman, Z.; Keller, L. P.; Agee, C. B.

    2016-01-01

    CK carbonaceous chondrites are a highly thermally altered group of carbonaceous chondrites, experiencing temperatures ranging between approximately 576-867 degrees Centigrade. Additionally, the mineralogy of the CK chondrites record the highest overall oxygen fugacity of all chondrites, above the fayalite-magnetite-quartz (FMQ) buffer. Me-tallic Fe-Ni is extremely rare in CK chondrites, but magnetite and Fe,Ni sulfides are commonly observed. Noble metal-rich inclusions have previously been found in some magnetite and sulfide grains. These arsenides, tellurides, and sulfides, which contain varying amounts of Pt, Ru, Os, Te, As, Ir, and S, are thought to form either by condensation from a solar gas, or by exsolution during metamorphism on the chondritic parent body. Northwest Africa (NWA) 8186 is a highly metamorphosed CK chondrite. This meteorite is predominately composed of NiO-rich forsteritic olivine (Fo65), with lesser amounts of plagioclase (An52), augite (Fs11Wo49), magnetite (with exsolved titanomagnetite, hercynite, and titanohematite), monosulfide solid solution (with exsolved pentlandite), and the phosphate minerals Cl-apatite and merrillite. This meteorite contains coarse-grained, homogeneous silicates, and has 120-degree triple junctions between mineral phases, which indicates a high degree of thermal metamorphism. The presence of NiO-rich olivine, oxides phases all bearing Fe3 plus, and the absence of metal, are consistent with an oxygen fugacity above the FMQ buffer. We also observed noble metal-rich phases within sulfide grains in NWA 8186, which are the primary focus of the present study.

  16. Accelerating the life of transistors

    Institute of Scientific and Technical Information of China (English)

    Qi Haochun; Lü Changzhi; Zhang Xiaoling; Xie Xuesong

    2013-01-01

    Choosing small and medium power switching transistors of the NPN type in a 3DK set as the study object,the test of accelerating life is conducted in constant temperature and humidity,and then the data are statistically analyzed with software developed by ourselves.According to degradations of such sensitive parameters as the reverse leakage current of transistors,the lifetime order of transistors is about more than 104 at 100 ℃ and 100% relative humidity (RH) conditions.By corrosion fracture of transistor outer leads and other failure modes,with the failure truncated testing,the average lifetime rank of transistors in different distributions is extrapolated about 103.Failure mechanism analyses of degradation of electrical parameters,outer lead fracture and other reasons that affect transistor lifetime are conducted.The findings show that the impact of external stress of outer leads on transistor reliability is more serious than that of parameter degradation.

  17. A Matterwave Transistor Oscillator

    CERN Document Server

    Caliga, Seth C; Zozulya, Alex A; Anderson, Dana Z

    2012-01-01

    A triple-well atomtronic transistor combined with forced RF evaporation is used to realize a driven matterwave oscillator circuit. The transistor is implemented using a metalized compound glass and silicon substrate. On-chip and external currents produce a cigar-shaped magnetic trap, which is divided into transistor source, gate, and drain regions by a pair of blue-detuned optical barriers projected onto the magnetic trap through a chip window. A resonant laser beam illuminating the drain portion of the atomtronic transistor couples atoms emitted by the gate to the vacuum. The circuit operates by loading the source with cold atoms and utilizing forced evaporation as a power supply that produces a positive chemical potential in the source, which subsequently drives oscillation. High-resolution in-trap absorption imagery reveals gate atoms that have tunneled from the source and establishes that the circuit emits a nominally mono-energetic matterwave with a frequency of 23.5(1.0) kHz by tunneling from the gate, ...

  18. Spin-torque transistor

    NARCIS (Netherlands)

    Bauer, G.E.W.; Brataas, A.; Tserkovnyak, Y.; Van Wees, B.J.

    2003-01-01

    A magnetoelectronic thin-film transistor is proposed that can display negative differential resistance and gain. The working principle is the modulation of the soure–drain current in a spin valve by the magnetization of a third electrode, which is rotated by the spin-torque created by a control spin

  19. Vertical organic transistors

    International Nuclear Information System (INIS)

    Organic switching devices such as field effect transistors (OFETs) are a key element of future flexible electronic devices. So far, however, a commercial breakthrough has not been achieved because these devices usually lack in switching speed (e.g. for logic applications) and current density (e.g. for display pixel driving). The limited performance is caused by a combination of comparatively low charge carrier mobilities and the large channel length caused by the need for low-cost structuring. Vertical Organic Transistors are a novel technology that has the potential to overcome these limitations of OFETs. Vertical Organic Transistors allow to scale the channel length of organic transistors into the 100 nm regime without cost intensive structuring techniques. Several different approaches have been proposed in literature, which show high output currents, low operation voltages, and comparatively high speed even without sub-μm structuring technologies. In this review, these different approaches are compared and recent progress is highlighted. (topical review)

  20. Radiation-hardened transistor and integrated circuit

    Science.gov (United States)

    Ma, Kwok K.

    2007-11-20

    A composite transistor is disclosed for use in radiation hardening a CMOS IC formed on an SOI or bulk semiconductor substrate. The composite transistor has a circuit transistor and a blocking transistor connected in series with a common gate connection. A body terminal of the blocking transistor is connected only to a source terminal thereof, and to no other connection point. The blocking transistor acts to prevent a single-event transient (SET) occurring in the circuit transistor from being coupled outside the composite transistor. Similarly, when a SET occurs in the blocking transistor, the circuit transistor prevents the SET from being coupled outside the composite transistor. N-type and P-type composite transistors can be used for each and every transistor in the CMOS IC to radiation harden the IC, and can be used to form inverters and transmission gates which are the building blocks of CMOS ICs.

  1. Spontaneous atomic ordering in MOVPE grown gallium arsenide antimonide

    Science.gov (United States)

    Jiang, Weiyang

    process. It is unlikely that the ordering mechanism is similar to the dimer-induced strain models that have been successfully used to explain CuPt ordering in InGaP. We propose a simple model based on alternating incorporation of group V adatoms at step edges. Keywords. GaAsSb; MOVPE; Bi surfactant; TEM; CuAu ordering. Subject. Gallium Arsenide Antimonide; Metalorganic Vapor-phase Epitaxy; Bismuth Surfactant; Transmission Electron Microscopy; CuAu Ordering.

  2. Gallium arsenide integrated optical devices for high-speed diagnostic systems

    International Nuclear Information System (INIS)

    The design, fabrication, and evaluation of waveguide electro-optic modulators in gallium arsenide for application to high-speed diagnostic systems are discussed specifically. This paper is focused on high bandwidth, single event analog modulation, and radiation susceptibility of these devices

  3. Light transport through disordered layers of dense gallium arsenide submicron particles

    NARCIS (Netherlands)

    Van der Beek, T.; Barthelemy, P.J.C.; Johnson, P.M.; Wiersma, D.S.; Lagendijk, A.

    2012-01-01

    We present a study of optical transport properties of powder layers with submicrometer, strongly scattering gallium arsenide (GaAs) particles. Uniform, thin samples with well controlled thicknesses were created through the use of varying grinding times, sedimentation fractionation, annealing, and a

  4. Boron, bismuth co-doping of gallium arsenide and other compounds for photonic and heterojunction bipolar transistor devices

    Science.gov (United States)

    Mascarenhas, Angelo

    2015-07-07

    Isoelectronic co-doping of semiconductor compounds and alloys with acceptors and deep donors is sued to decrease bandgap, to increase concentration of the dopant constituents in the resulting alloys, and to increase carrier mobilities lifetimes. For example, Group III-V compounds and alloys, such as GaAs and GaP, are isoelectronically co-doped with, for example, B and Bi, to customize solar cells, and other semiconductor devices. Isoelectronically co-doped Group II-VI compounds and alloys are also included.

  5. Metatronic transistor amplifier

    Science.gov (United States)

    Chettiar, Uday K.; Engheta, Nader

    2015-10-01

    Utilizing the notion of metamaterials, in recent years the concept of a circuit and lumped circuit elements have been extended to the optical domains, providing the paradigm of optical metatronics, i.e., metamaterial-inspired optical nanocircuitry, as a powerful tool for design and study of more complex systems at the nanoscale. In this paper we present a design for a new metatronic element, namely, a metatronic transistor that functions as an amplifier. As shown by our analytical and numerical paper here, this metatronic transistor provides gain as well as isolation between the input and output ports of such two-port device. The cascadability and fan-out aspects of this element are also explored.

  6. TRANSISTOR HIGH VOLTAGE POWER SUPPLY

    Science.gov (United States)

    Driver, G.E.

    1958-07-15

    High voltage, direct current power supplies are described for use with battery powered nuclear detection equipment. The particular advantages of the power supply described, are increased efficiency and reduced size and welght brought about by the use of transistors in the circuit. An important feature resides tn the employment of a pair of transistors in an alternatefiring oscillator circuit having a coupling transformer and other circuit components which are used for interconnecting the various electrodes of the transistors.

  7. Polarization induced doped transistor

    Energy Technology Data Exchange (ETDEWEB)

    Xing, Huili (Grace); Jena, Debdeep; Nomoto, Kazuki; Song, Bo; Zhu, Mingda; Hu, Zongyang

    2016-06-07

    A nitride-based field effect transistor (FET) comprises a compositionally graded and polarization induced doped p-layer underlying at least one gate contact and a compositionally graded and doped n-channel underlying a source contact. The n-channel is converted from the p-layer to the n-channel by ion implantation, a buffer underlies the doped p-layer and the n-channel, and a drain underlies the buffer.

  8. Spin Hall effect transistor

    Czech Academy of Sciences Publication Activity Database

    Wunderlich, Joerg; Park, B.G.; Irvine, A.C.; Zarbo, Liviu; Rozkotová, E.; Němec, P.; Novák, Vít; Sinova, Jairo; Jungwirth, Tomáš

    2010-01-01

    Roč. 330, č. 6012 (2010), s. 1801-1804. ISSN 0036-8075 R&D Projects: GA AV ČR KAN400100652; GA MŠk LC510 Grant ostatní: EU FP7 SemiSpinNet(XE) 215368 Institutional research plan: CEZ:AV0Z10100521 Keywords : spin Hall effect * spintronics * spin transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 31.364, year: 2010

  9. Biological availability of nickel arsenides: toxic effects of particulate Ni/sub 5/As/sub 2/

    Energy Technology Data Exchange (ETDEWEB)

    Gurley, L.R.; Tobey, R.A.; Valdez, J.G.; Halleck, M.S.; Barham, S.S.

    1981-01-01

    Considerations of (1) oil shale retort operating conditions, (2) oil shale elemental composition, (3) nickel and arsenic physico-chemical properties, and (4) oil shale matrix structure lead to the suggestion that nickel arsenides may be formed during the oil shale retorting process. The biological effects of nickel arsenides have not been previously studied. However, similarities between nickel subarsenide and nickel subsulfide and nickel subselenimide, both of which are known potent carcinogens, have caused concern that nickel arsenides may have adverse effects on biological systems. To determine if fugitive nickel arsenides from an oil shale retort could pose a threat to personnel in the workplace or to other living organisms in the environment, a program to study the toxicity of nickel arsenides has been initiated. Five stable nickel arsenides (Ni/sub 5/As/sub 2/, Ni/sub 2/As, Ni/sub 11/As/sub 8/, NiAs, and NiAs/sub 2/) and nickel arsenic sulfide (NiAsS) are considered possible species for study.

  10. REGENERATIVE TRANSISTOR AMPLIFIER

    Science.gov (United States)

    Kabell, L.J.

    1958-11-25

    Electrical circults for use in computers and the like are described. particularly a regenerative bistable transistor amplifler which is iurned on by a clock signal when an information signal permits and is turned off by the clock signal. The amplifier porforms the above function with reduced power requirements for the clock signal and circuit operation. The power requirements are reduced in one way by employing transformer coupling which increases the collector circuit efficiency by eliminating the loss of power in the collector load resistor.

  11. The coupled atom transistor

    International Nuclear Information System (INIS)

    We describe the first implementation of a coupled atom transistor where two shallow donors (P or As) are implanted in a nanoscale silicon nanowire and their electronic levels are controlled with three gate voltages. Transport spectroscopy through these donors placed in series is performed both at zero and microwave frequencies. The coherence of the charge transfer between the two donors is probed by Landau–Zener–Stückelberg interferometry. Single-charge transfer at zero bias (electron pumping) has been performed and the crossover between the adiabatic and non-adiabatic regimes is studied. (paper)

  12. First-Principles Determination of Ultrahigh Thermal Conductivity of Boron Arsenide: A Competitor for Diamond?

    Science.gov (United States)

    Lindsay, L.; Broido, D. A.; Reinecke, T. L.

    2013-07-01

    We have calculated the thermal conductivities (κ) of cubic III-V boron compounds using a predictive first principles approach. Boron arsenide is found to have a remarkable room temperature κ over 2000Wm-1K-1; this is comparable to those in diamond and graphite, which are the highest bulk values known. We trace this behavior in boron arsenide to an interplay of certain basic vibrational properties that lie outside of the conventional guidelines in searching for high κ materials, and to relatively weak phonon-isotope scattering. We also find that cubic boron nitride and boron antimonide will have high κ with isotopic purification. This work provides new insight into the nature of thermal transport at a quantitative level and predicts a new ultrahigh κ material of potential interest for passive cooling applications.

  13. Monolithic metal oxide transistors.

    Science.gov (United States)

    Choi, Yongsuk; Park, Won-Yeong; Kang, Moon Sung; Yi, Gi-Ra; Lee, Jun-Young; Kim, Yong-Hoon; Cho, Jeong Ho

    2015-04-28

    We devised a simple transparent metal oxide thin film transistor architecture composed of only two component materials, an amorphous metal oxide and ion gel gate dielectric, which could be entirely assembled using room-temperature processes on a plastic substrate. The geometry cleverly takes advantage of the unique characteristics of the two components. An oxide layer is metallized upon exposure to plasma, leading to the formation of a monolithic source-channel-drain oxide layer, and the ion gel gate dielectric is used to gate the transistor channel effectively at low voltages through a coplanar gate. We confirmed that the method is generally applicable to a variety of sol-gel-processed amorphous metal oxides, including indium oxide, indium zinc oxide, and indium gallium zinc oxide. An inverter NOT logic device was assembled using the resulting devices as a proof of concept demonstration of the applicability of the devices to logic circuits. The favorable characteristics of these devices, including (i) the simplicity of the device structure with only two components, (ii) the benign fabrication processes at room temperature, (iii) the low-voltage operation under 2 V, and (iv) the excellent and stable electrical performances, together support the application of these devices to low-cost portable gadgets, i.e., cheap electronics. PMID:25777338

  14. Suppression of decoherence in gallium arsenide multiple quantum wells by means of bang-bang control

    Energy Technology Data Exchange (ETDEWEB)

    Takasago, K. [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan)], E-mail: takasago.k.aa@m.titech.ac.jp; Ogawa, Y.; Minami, F. [Department of Physics, Tokyo Institute of Technology, Meguro-ku, Tokyo 152-8551 (Japan)

    2008-05-15

    We performed a three-pulse six-wave mixing (SWM) measurement on a gallium arsenide (GaAs) multiple quantum well and observed the time-resolved SWM signal using the heterodyne detection technique. The second pulse acts as a {pi} pulse that reverses the time evolution of the non-Markovian dynamics. By changing the pulse interval conditions, we confirmed the suppression of exciton decoherence by {pi} pulse irradiation (bang-bang control)

  15. The diamond RF-transistor model

    Directory of Open Access Journals (Sweden)

    Altukhov A. A.

    2011-12-01

    Full Text Available In this work is shown that fluent shutter model it is enough well describes work field-effect diamond RF-transistors. Using this model, possible to calculate transistor parameters used electronic parameters of the diamond structure with δ-doped (hydrogen or boron layer and geometric parameter transistor element. Proof, are calculated by us main parameters model RF-transistor, which it is enough close comply with published experimental result of the measurements real RF-transistors.

  16. Current Status of Graphene Transistors

    OpenAIRE

    Lemme, Max. C.

    2009-01-01

    This paper reviews the current status of graphene transistors as potential supplement to silicon CMOS technology. A short overview of graphene manufacturing and metrology methods is followed by an introduction of macroscopic graphene field effect transistors (FETs). The absence of an energy band gap is shown to result in severe shortcomings for logic applications. Possibilities to engineer a band gap in graphene FETs including quantum confinement in graphene Nanoribbons (GNRs) and electricall...

  17. Differential Bloch Oscillating Transistor Pair

    OpenAIRE

    Sarkar, Jayanta; Puska, Antti; Hassel, Juha; Hakonen, Pertti J.

    2013-01-01

    We examine a Bloch Oscillating Transistor pair as a differential stage for cryogenic low-noise measurements. Using two oppositely biased, nearly symmetric Bloch Oscillating Transistors, we measured the sum and difference signals in the current gain and transconductance modes while changing the common mode signal, either voltage or current. From the common mode rejection ratio we find values $\\sim 20$ dB even under non-optimal conditions. We also characterize the noise properties and obtain ex...

  18. Gate-enclosed NMOS transistors

    Institute of Scientific and Technical Information of China (English)

    Fan Xue; Li Ping; Li Wei; Zhang Bin; Xie Xiaodong; Wang Gang; Hu Bin; Zhai Yahong

    2011-01-01

    In order to quantitatively compare the design cost and performance of various gate styles,NMOS transistors with two-edged,annular and ring gate layouts were designed and fabricated by a commercial 0.35 μm CMOS process.By comparing the minimum W/L ratios and transistor areas,it was found that either the annular layout or its ring counterpart incurs a higher area penalty that depends on the W/L ratio of the transistor to be designed.Furthermore,by comparing the output and transfer characteristics of the transistors and analyzing the popular existing methods for extracting the effective W/L ratio,it was shown that the mid-line approximation for annular NMOS could incur an error of more than 10%.It was also demonstrated that the foundry-provided extraction tool needs significant adaptation when being applied to the enclosed-gate transistors,since it is targeted only toward the two-edged transistor.A simple approach for rough extraction of the W/L ratio for the ring-gate NMOS was presented and its effectiveness was confirmed by the experimental results with an error up to 8%.

  19. Electron tunneling transport across heterojunctions between europium sulfide and indium arsenide

    Science.gov (United States)

    Kallaher, Raymond L.

    This dissertation presents research done on utilizing the ferromagnetic semiconductor europium sulfide (EuS) to inject spin polarized electrons into the non-magnetic semiconductor indium arsenide (InAs). There is great interest in expanding the functionality of modern day electronic circuits by creating devices that depend not only on the flow of charge in the device, but also on the transport of spin through the device. Within this mindset, there is a concerted effort to establish an efficient means of injecting and detecting spin polarized electrons in a two dimensional electron system (2DES) as the first step in developing a spin based field effect transistor. Thus, the research presented in this thesis has focused on the feasibility of using EuS, in direct electrical contact with InAs, as a spin injecting electrode into an InAs 2DES. Doped EuS is a concentrated ferromagnetic semiconductor, whose conduction band undergoes a giant Zeeman splitting when the material becomes ferromagnetic. The concomitant difference in energy between the spin-up and spin-down energy bands makes the itinerant electrons in EuS highly spin polarized. Thus, in principle, EuS is a good candidate to be used as an injector of spin polarized electrons into non-magnetic materials. In addition, the ability to adjust the conductivity of EuS by varying the doping level in the material makes EuS particularly suited for injecting spins into non-magnetic semiconductors and 2DES. For this research, thin films of EuS have been grown via e-beam evaporation of EuS powder. This growth technique produces EuS films that are sulfur deficient; these sulfur vacancies act as intrinsic electron donors and the resulting EuS films behave like heavily doped ferromagnetic semiconductors. The growth parameters and deposition procedures were varied and optimized in order to fabricate films that have minimal crystalline defects. Various properties and characteristics of these EuS films were measured and compared to

  20. Design of Indium Arsenide nanowire sensors for pH and biological sensing and low temperature transport through p-doped Indium Arsenide nanowires

    DEFF Research Database (Denmark)

    Upadhyay, Shivendra

    H sensing, we apply the same to a more complex system - proteins. The sensing protocol involves the functionalization of the sensor surface with a receptor protein followed by the addition of the protein of interest. Sensor response to oppositely charged proteins is used to confirm the sensitivity of the......With the goal of real time electrical detection of chemical and biological species, nanowires have shown great promise with high sensitivity due to their large surface to volume ratio. While the focus of such electrical detection has shifted to one dimensional semiconductor nanostuctures, Silicon...... remains the primary material of choice. This research is about investigating Indium Arsenide nanowires as alternative platform for sensing charged species - chemical and biological, in solution. Starting with nanowires grown via molecular beam epitaxy in an ultra-high vacuum chamber, we discuss the...

  1. The metabolism of inorganic arsenic oxides, gallium arsenide, and arsine: a toxicochemical review

    International Nuclear Information System (INIS)

    The aim of this review is to compare the metabolism, chemistry, and biological effects to determine if either of the industrial arsenicals (arsine and gallium arsenide) act like the environmental arsenic oxides (arsenite and arsenate). The metabolism of the arsenic oxides has been extensively investigated in the past 4 years and the differences between the arsenic metabolites in the oxidation states +III versus +V and with one or two methyl groups added have shown increased importance. The arsenic oxide metabolism has been compared with arsine (oxidation state -III) and arsenide (oxidation state between 0 to -III). The different metabolites appear to have different strengths of reaction for binding aresenic (III) to thiol groups, their oxidation-reduction reactions and their forming an arsenic-carbon bond. It is unclear if the differences in parameters such as the presence or absence of methyl metabolities, the rates of AsV reduction compared to the rates of AsIII oxidation, or the competition of phosphate and arsenate for cellular uptake are large enough to change biological effects. The arsine rate of decomposition, products of metabolism, target organ of toxic action, and protein binding appeared to support an oxidized arsenic metabolite. This arsine metabolite was very different from anything made by the arsenic oxides. The gallium arsenide had a lower solubility than any other arsenic compound and it had a disproportionate intensity of lung damage to suggest that the GaAs had a site of contact interaction and that oxidation reactions were important in its toxicity. The urinary metabolites after GaAs exposure were the same as excreted by arsenic oxides but the chemical compounds responsible for the toxic effects of GaAs are different from the aresnic oxides. The review concludes that there is insufficient evidence to equate the different arsenic compounds. There are several differences in the toxicity of the arsenic compounds that will require substantial

  2. Quantum Point Contact Transistor and Ballistic Field-Effect Transistors

    International Nuclear Information System (INIS)

    We report the experimental results and theoretical understanding of the Quantum Point Contact Transistor - a fully ballistic one-dimensional (1D) Field-Effect Transistor (FET). Experimentally obtained voltage gain greater than 1 in our Quantum-Point-Contact transistors at 4.2 K can be explained with the help of an analytical modeling based on the Landauer-Büttiker approach in mesosopic physics: the lowest 1D subband and the band gap play the key role in increasing its transconductance, especially by reducing its output conductance, and thus achieving a voltage gain higher than 1. This work provides a general basis for devising future ballistic FETs and the quantum limits found in this work may be used to estimate normalized transconductance and channel resistance in future two-dimensional (2D) ballistic FETs.

  3. Growth of Gold-assisted Gallium Arsenide Nanowires on Silicon Substrates via Molecular Beam Epitaxy

    Directory of Open Access Journals (Sweden)

    Ramon M. delos Santos

    2008-06-01

    Full Text Available Gallium arsenide nanowires were grown on silicon (100 substrates by what is called the vapor-liquid-solid (VLS growth mechanism using a molecular beam epitaxy (MBE system. Good quality nanowires with surface density of approximately 108 nanowires per square centimeter were produced by utilizing gold nanoparticles, with density of 1011 nanoparticles per square centimeter, as catalysts for nanowire growth. X-ray diffraction measurements, scanning electron microscopy, transmission electron microscopy and Raman spectroscopy revealed that the nanowires are epitaxially grown on the silicon substrates, are oriented along the [111] direction and have cubic zincblende structure.

  4. An examination of the reactive sputtering of silicon nitride on to gallium arsenide

    International Nuclear Information System (INIS)

    The deposition of silicon nitride thin films by the reactive sputtering of elemental silicon in a nitrogen/argon plasma has been investigated. The composition of the films has been examined using infra-red reflectance, X-ray photoelectron and Auger electron spectroscopies and spark source mass spectrometry. Oxygen has been found to be a major contaminant in these sputter deposited films, the oxygen concentration depending on the ambient gas pressure. The use of the silicon oxy-nitride films as annealing encapsulants for the activation of silicon ion implanted semi-insulating gallium arsenide has also been investigated. (author)

  5. Passivated ambipolar black phosphorus transistors

    Science.gov (United States)

    Yue, Dewu; Lee, Daeyeong; Jang, Young Dae; Choi, Min Sup; Nam, Hye Jin; Jung, Duk-Young; Yoo, Won Jong

    2016-06-01

    We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ~83 cm2 V-1 s-1 from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ~10 nm thick BP flake was used.We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ~83 cm2 V-1 s-1 from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ~10 nm thick BP flake was used. Electronic supplementary information (ESI) available: Transfer characteristics of BP field effect transistors (BV1-BV4) (Fig. S1 and S2 and Table S1); output characteristics of BP field effect transistors in different directions (Fig. S3

  6. Logarithmic current-measuring transistor circuits

    DEFF Research Database (Denmark)

    Højberg, Kristian Søe

    1967-01-01

    Describes two transistorized circuits for the logarithmic measurement of small currents suitable for nuclear reactor instrumentation. The logarithmic element is applied in the feedback path of an amplifier, and only one dual transistor is used as logarithmic diode and temperature compensating...... transistor. A simple one-amplifier circuit is compared with a two-amplifier system. The circuits presented have been developed in connexion with an amplifier using a dual m.o.s. transistor input stage with diode-protected gates....

  7. Passivated ambipolar black phosphorus transistors.

    Science.gov (United States)

    Yue, Dewu; Lee, Daeyeong; Jang, Young Dae; Choi, Min Sup; Nam, Hye Jin; Jung, Duk-Young; Yoo, Won Jong

    2016-07-01

    We report the first air-passivated ambipolar BP transistor formed by applying benzyl viologen, which serves as a surface charge transfer donor for BP flakes. The passivated BP devices exhibit excellent stability under both an ambient atmosphere and vacuum; their transistor performance is maintained semi-permanently. Unlike their intrinsic p-type properties, passivated BP devices present advantageous ambipolar properties with much higher electron mobility up to ∼83 cm(2) V(-1) s(-1) from 2-terminal measurement at 300 K, compared to other reported studies on n-type BP transistors. On the basis of the n-type doping effect that originated from benzyl viologen, we also systematically investigated the BP thickness dependence of our devices on electrical properties, in which we found the best electron transport performance to be attained when an ∼10 nm thick BP flake was used. PMID:27283027

  8. High current gain transistor laser

    Science.gov (United States)

    Liang, Song; Qiao, Lijun; Zhu, Hongliang; Wang, Wei

    2016-06-01

    A transistor laser (TL), having the structure of a transistor with multi-quantum wells near its base region, bridges the functionality gap between lasers and transistors. However, light emission is produced at the expense of current gain for all the TLs reported up to now, leading to a very low current gain. We propose a novel design of TLs, which have an n-doped InP layer inserted in the emitter ridge. Numerical studies show that a current flow aperture for only holes can be formed in the center of the emitter ridge. As a result, the common emitter current gain can be as large as 143.3, which is over 15 times larger than that of a TL without the aperture. Besides, the effects of nonradiative recombination defects can be reduced greatly because the flow of holes is confined in the center region of the emitter ridge.

  9. Electrostatics of Silicon Nano Transistor

    Directory of Open Access Journals (Sweden)

    Lalit Singh

    2011-01-01

    Full Text Available Nano Transistor represents a unique system for exploring physical phenomena pertaining to charge transport at the nano scale and is expected to play a critical role in future evolution of electronic and optoelectronic devices. This paper summarizes some of the essential electrostatics of nano Metal Oxide Semiconductor Field effect Transistor (MOSFET and their electrical properties. Though the general focus of this work is on surface potential yet the first part presents a brief discussion of the independence of charge at the top of the barrier in the channel of MOS Transistor on Drain voltage. The quantum capacitance is discussed at length. The superposition theorem is used, thereafter, to obtain an expression for self consistent potential in the channel. Finally the I-V characteristics of the device are explored using Landauer formalism. The simulated results for a device are observed to represent the realistic behaviour of the device.

  10. Tunneling field effect transistor technology

    CERN Document Server

    Chan, Mansun

    2016-01-01

    This book provides a single-source reference to the state-of-the art in tunneling field effect transistors (TFETs). Readers will learn the TFETs physics from advanced atomistic simulations, the TFETs fabrication process and the important roles that TFETs will play in enabling integrated circuit designs for power efficiency. · Provides comprehensive reference to tunneling field effect transistors (TFETs); · Covers all aspects of TFETs, from device process to modeling and applications; · Enables design of power-efficient integrated circuits, with low power consumption TFETs.

  11. Electronic components, tubes and transistors

    CERN Document Server

    Dummer, G W A

    1965-01-01

    Electronic Components, Tubes and Transistors aims to bridge the gap between the basic measurement theory of resistance, capacitance, and inductance and the practical application of electronic components in equipments. The more practical or usage aspect of electron tubes and semiconductors is given emphasis over theory. The essential characteristics of each main type of component, tube, and transistor are summarized. This book is comprised of six chapters and begins with a discussion on the essential characteristics in terms of the parameters usually required in choosing a resistor, including s

  12. Single Electron Transistor: Applications & Problems

    Directory of Open Access Journals (Sweden)

    Om Kumar

    2010-12-01

    Full Text Available The goal of this paper is to review in brief the basic physics of nanoelectronic device single-electron transistor [SET] as well as prospective applications and problems in their applications. SET functioning based on the controllable transfer of single electrons between small conducting "islands". The device properties dominated by the quantum mechanical properties of matter and provide new characteristics coulomb oscillation, coulomb blockade that is helpful in a number of applications. SET is able to shear domain with silicon transistor in near future and enhance the device density. Recent research in SET gives new ideas which are going to revolutionize the random access memory and digital data storage technologies.

  13. Ab initio study of the unusual thermal transport properties of boron arsenide and related materials

    Science.gov (United States)

    Broido, D. A.; Lindsay, L.; Reinecke, T. L.

    2013-12-01

    Recently, using a first principles approach, we predicted that zinc blende boron arsenide (BAs) will have an ultrahigh lattice thermal conductivity, κ, of over 2000 Wm-1K-1 at room temperature (RT), comparable to that of diamond. Here, we provide a detailed ab initio examination of phonon thermal transport in boron arsenide, contrasting its unconventional behavior with that of other related materials, including the zinc blende crystals boron nitride (BN), boron phosphide, boron antimonide, and gallium nitride (GaN). The unusual vibrational properties of BAs contribute to its weak phonon-phonon scattering and phonon-isotope scattering, which are responsible for its exceptionally high κ. The thermal conductivity of BAs has contributions from phonons with anomalously large mean free paths (˜2 μm), two to three times those of diamond and BN. This makes κ in BAs sensitive to phonon scattering from crystal boundaries. An order of magnitude smaller RT thermal conductivity in a similar material, zinc blende GaN, is connected to more separated acoustic phonon branches, larger anharmonic force constants, and a large isotope mixture on the heavy rather than the light constituent atom. The striking difference in κ for BAs and GaN demonstrates the importance of using a microscopic first principles thermal transport approach for calculating κ. BAs also has an advantageous RT coefficient of thermal expansion, which, combined with the high κ value, suggests that it is a promising material for use in thermal management applications.

  14. THE QUANTUM-WELL STRUCTURES OF SELF ELECTROOPTIC-EFFECT DEVICES AND GALLIUM-ARSENIDE

    Directory of Open Access Journals (Sweden)

    Mustafa TEMİZ

    1996-02-01

    Full Text Available Multiple quantum-well (MQW electroabsorptive self electro optic-effect devices (SEEDs are being extensively studied for use in optical switching and computing. The self electro-optic-effect devices which has quantum-well structures is a new optoelectronic technology with capability to obtain both optical inputs and outputs for Gallium-Arsenide/Aluminum Gallium-Arsenide (GaAs/AlGaAs electronic circuits. The optical inputs and outputs are based on quantum-well absorptive properties. These quantum-well structures consist of many thin layers of semiconductors materials of GaAs/AlGaAs which have emerged some important directions recently. The most important advance in the physics of these materials since the early days has been invention of the heterojunction structures which is based at present on GaAs technology. GaAs/AlGaAs structures present some important advantages to relevant band gap and index of refraction which allow to form the quantum-well structures and also to make semiconductor lasers, dedectors and waveguide optical switches.

  15. Optimal power settings of aluminum gallium arsenide lasers in caries inhibition — An in vitro study

    Science.gov (United States)

    Sharma, Sonali; Hegde, Mithra N; Sadananda, Vandana; Mathews, Blessen

    2016-01-01

    Context: Incipient carious lesions are characterized by subsurface dissolution due to more fluoride ions in the 50-100 microns of the tooth's outer surface. Aims: To determine an optimal power setting for 810 nm aluminum gallium arsenide laser for caries inhibition. Materials and Methods: Fifty-four caries-free extracted teeth were sectioned mesiodistally. The samples were divided into 18 groups for each power setting being evaluated. Each group had six samples. The laser used is 810 nm aluminum gallium arsenide laser with power setting from 0.1 watts to 5 watts. Laser fluorescence based device was used to evaluate the effect of irradiation. Statistical Analysis Used: Paired “t” test, one-way analysis of variance (ANOVA), Tukey's post hoc test, and the Pearson's correlation test. Results: The paired t-test showed that there is minimum divergence from the control for 3.5 watts. Tukey's post hoc test also showed statistically significantly results for 3.5 watts. The Pearson's correlation test showed that there was negative correlation between the watts and irradiation. Conclusions: The power setting that gave statistically significant results was 3.5 watts. PMID:27099427

  16. Silicon on insulator self-aligned transistors

    Science.gov (United States)

    McCarthy, Anthony M.

    2003-11-18

    A method for fabricating thin-film single-crystal silicon-on-insulator (SOI) self-aligned transistors. Standard processing of silicon substrates is used to fabricate the transistors. Physical spaces, between the source and gate, and the drain and gate, introduced by etching the polysilicon gate material, are used to provide connecting implants (bridges) which allow the transistor to perform normally. After completion of the silicon substrate processing, the silicon wafer is bonded to an insulator (glass) substrate, and the silicon substrate is removed leaving the transistors on the insulator (glass) substrate. Transistors fabricated by this method may be utilized, for example, in flat panel displays, etc.

  17. Black phosphorus nonvolatile transistor memory.

    Science.gov (United States)

    Lee, Dain; Choi, Yongsuk; Hwang, Euyheon; Kang, Moon Sung; Lee, Seungwoo; Cho, Jeong Ho

    2016-04-28

    We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (10(4) s), and cyclic endurance (1000 cycles). PMID:27074903

  18. The four-gate transistor

    Science.gov (United States)

    Mojarradi, M. M.; Cristoveanu, S.; Allibert, F.; France, G.; Blalock, B.; Durfrene, B.

    2002-01-01

    The four-gate transistor or G4-FET combines MOSFET and JFET principles in a single SOI device. Experimental results reveal that each gate can modulate the drain current. Numerical simulations are presented to clarify the mechanisms of operation. The new device shows enhanced functionality, due to the combinatorial action of the four gates, and opens rather revolutionary applications.

  19. A High-Voltage Level Tolerant Transistor Circuit

    NARCIS (Netherlands)

    Annema, Anne Johan; Geelen, Godefridus Johannes Gertrudis Maria

    2001-01-01

    A high-voltage level tolerant transistor circuit, comprising a plurality of cascoded transistors, including a first transistor (T1) operatively connected to a high-voltage level node (3) and a second transistor (T2) operatively connected to a low-voltage level node (2). The first transistor (T1) con

  20. NMR studies on the new iron arsenide superconductors including the superconducting state

    International Nuclear Information System (INIS)

    We summarize our Nuclear Magnetic Resonance (NMR) and Nuclear Quadrupole Resonance (NQR) results on the new iron arsenide superconductor LaO1-xFxFeAs in the normal state, and show new NMR data in the superconducting state. Beyond early evidence of nodes and spin-singlet pairing[2], we find evidence of a deviation of the T3 behaviour of the spin lattice relaxation rate, 1/T1, at temperatures significantly below Tc, which would agree with the suggested extended s-wave symmetry. The deviation of the T3 behaviour is induced by the pair breaking effect of impurities. Different amounts of impurities would lead to different temperature dependences of 1/T1, which would allow to differentiate between d-wave and extended s-wave symmetries.

  1. Electronic structure, magnetic and superconducting properties of co-doped iron-arsenide superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Rosner, Helge; Schnelle, Walter; Nicklas, Michael; Leithe-Jasper, Andreas [MPI CPfS Dresden (Germany); Weikert, Franziska [Los Alamos National Laboratory, New Mexico (United States); HLD Dresden Rossendorf (Germany); Wosnitza, Joachim [HLD Dresden Rossendorf (Germany)

    2013-07-01

    We present a joint experimental and theoretical study of co-doped iron-arsenide superconductors of the 122 family A{sub 1-x}K{sub x}Fe{sub 2-y}T{sub y}As{sub 2} (A = Ba,Sr,Eu; T = Co,Ru,Rh). In these systems, the co-doping enables the separation of different parameters - like electron count, disorder or the specific geometry of the FeAs layer - with respect to the position of the respective compounds in the general 122 phase diagram. For a series of compounds, we investigate the relevance of the different parameters for the magnetic, thermodynamic and superconducting properties. Our experimental investigations are supported by density functional electronic structure calculations applying different approximations for doping and disorder.

  2. Gallium arsenide quantum well-based far infrared array radiometric imager

    Science.gov (United States)

    Forrest, Kathrine A.; Jhabvala, Murzy D.

    1991-01-01

    We have built an array-based camera (FIRARI) for thermal imaging (lambda = 8 to 12 microns). FIRARI uses a square format 128 by 128 element array of aluminum gallium arsenide quantum well detectors that are indium bump bonded to a high capacity silicon multiplexer. The quantum well detectors offer good responsivity along with high response and noise uniformity, resulting in excellent thermal images without compensation for variation in pixel response. A noise equivalent temperature difference of 0.02 K at a scene temperature of 290 K was achieved with the array operating at 60 K. FIRARI demonstrated that AlGaAS quantum well detector technology can provide large format arrays with performance superior to mercury cadmium telluride at far less cost.

  3. Methods for forming group III-V arsenide-nitride semiconductor materials

    Science.gov (United States)

    Major, Jo S. (Inventor); Welch, David F. (Inventor); Scifres, Donald R. (Inventor)

    2000-01-01

    Methods are disclosed for forming Group III--arsenide-nitride semiconductor materials. Group III elements are combined with group V elements, including at least nitrogen and arsenic, in concentrations chosen to lattice match commercially available crystalline substrates. Epitaxial growth of these III-V crystals results in direct bandgap materials, which can be used in applications such as light emitting diodes and lasers. Varying the concentrations of the elements in the III-V crystals varies the bandgaps, such that materials emitting light spanning the visible spectra, as well as mid-IR and near-UV emitters, can be created. Conversely, such material can be used to create devices that acquire light and convert the light to electricity, for applications such as full color photodetectors and solar energy collectors. The growth of the III-V crystals can be accomplished by growing thin layers of elements or compounds in sequences that result in the overall lattice match and bandgap desired.

  4. Ultrafast Relaxation Dynamics of Photo-excited Dirac Fermion in Three Dimensional Dirac Semimetal Cadmium Arsenide

    CERN Document Server

    Lu, Wei; Liu, Xuefeng; Lu, Hong; Li, Caizhen; Lai, Jiawei; Zhao, Chuan; Tian, Ye; Liao, Zhimin; Jia, Shuang; Sun, Dong

    2016-01-01

    Three dimensional (3D) Dirac semimetal exhibiting ultrahigh mobility has recently attracted enormous research interests as 3D analogues of graphene. From the prospects of future application toward electronic/optoelectronic devices with extreme performance, it is crucial to understand the relaxation dynamics of photo-excited carriers and their coupling with lattice. In this work, we report ultrafast transient reflection measurements of photo-excited carrier dynamics in cadmium arsenide (Cd3As2), which is among the most stable Dirac semimetals that have been confirmed experimentally. With low energy probe photon of 0.3 eV, photo-excited Dirac Fermions dynamics closing to Dirac point are probed. Through transient reflection measurements on bulk and nanoplate samples that have different doping intensities, and systematic probe wavelength, pump power and lattice temperature dependent measurements, the dynamical evolution of carrier distributions can be retrieved qualitatively using a two-temperature model. The pho...

  5. Quantum oscillations in the parent magnetic phase of an iron arsenide high temperature superconductor.

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian, Suchitra [Cambridge University; Gillett, J [Cambridge University; Harrison, N [Los Alamos National Laboratory (LANL); Lau, P H C [Cambridge University; Singh, David J [ORNL; Mielke, C H [Los Alamos National Laboratory (LANL); Lonzarich, G G [Cambridge University

    2008-01-01

    We report measurements of quantum oscillations in SrFe{sub 2}As{sub 2}--which is an antiferromagnetic parent of the iron arsenide family of superconductors--known to become superconducting under doping and the application of pressure. The magnetic field and temperature dependences of the oscillations between 20 and 55 T in the liquid helium temperature range suggest that the electronic excitations are those of a Fermi liquid. We show that the observed Fermi surface comprising small pockets is consistent with the formation of a spin-density wave. Our measurements thus demonstrate that high T{sub c} superconductivity can occur on doping or pressurizing a conventional metallic spin-density wave state.

  6. Quantum oscillations in the parent magnetic phase of an iron arsenide high temperature superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian, Suchitra E; Gillett, J; Lau, P H C; Lonzarich, G G [Cavendish Laboratory, Cambridge University, J J Thomson Avenue, Cambridge CB3 OHE (United Kingdom); Harrison, N; Mielke, C H [NHMFL, Los Alamos National Laboratory, MS E536, Los Alamos, NM 87545 (United States); Singh, D J [Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)], E-mail: suchitra@phy.cam.ac.uk

    2008-10-22

    We report measurements of quantum oscillations in SrFe{sub 2}As{sub 2}-which is an antiferromagnetic parent of the iron arsenide family of superconductors-known to become superconducting under doping and the application of pressure. The magnetic field and temperature dependences of the oscillations between 20 and 55 T in the liquid helium temperature range suggest that the electronic excitations are those of a Fermi liquid. We show that the observed Fermi surface comprising small pockets is consistent with the formation of a spin-density wave. Our measurements thus demonstrate that high T{sub c} superconductivity can occur on doping or pressurizing a conventional metallic spin-density wave state. (fast track communication)

  7. Development of a dome Fresnel lens/gallium arsenide photovoltaic concentrator for space applications

    Science.gov (United States)

    O'Neill, Mark J.; Piszczor, Michael F.

    1987-01-01

    A novel photovoltaic concentrator system is currently being developed. Phase I of the program, completed in late 1986, produced a conceptual design for the concentrator system, including an array weight and performance estimates based on optical, electrical, and thermal analyses. Phase II of the program, just underway, concerns the fabrication and testing of prototype concentrator panels of the design. The concentrator system uses dome Fresnel lenses for optical concentration; gallium arsenide concentrator cells for power generation; prismatic cell covers to eliminate gridline obscuration losses; a backplane radiator for heat rejection; and a honeycomb structure for the deployable panel assembly. The conceptual design of the system, its anticipated performance, and its estimated weight are reported.

  8. Electronic structure, magnetic and superconducting properties of co-doped iron-arsenide superconductors

    International Nuclear Information System (INIS)

    We present a joint experimental and theoretical study of co-doped iron-arsenide superconductors of the 122 family A1-xKxFe2-yTyAs2 (A = Ba,Sr,Eu; T = Co,Ru,Rh). In these systems, the co-doping enables the separation of different parameters - like electron count, disorder or the specific geometry of the FeAs layer - with respect to the position of the respective compounds in the general 122 phase diagram. For a series of compounds, we investigate the relevance of the different parameters for the magnetic, thermodynamic and superconducting properties. Our experimental investigations are supported by density functional electronic structure calculations applying different approximations for doping and disorder.

  9. Outdoor Performance of a Thin-Film Gallium-Arsenide Photovoltaic Module

    Energy Technology Data Exchange (ETDEWEB)

    Silverman, T. J.; Deceglie, M. G.; Marion, B.; Cowley, S.; Kayes, B.; Kurtz, S.

    2013-06-01

    We deployed a 855 cm2 thin-film, single-junction gallium arsenide (GaAs) photovoltaic (PV) module outdoors. Due to its fundamentally different cell technology compared to silicon (Si), the module responds differently to outdoor conditions. On average during the test, the GaAs module produced more power when its temperature was higher. We show that its maximum-power temperature coefficient, while actually negative, is several times smaller in magnitude than that of a Si module used for comparison. The positive correlation of power with temperature in GaAs is due to temperature-correlated changes in the incident spectrum. We show that a simple correction based on precipitable water vapor (PWV) brings the photocurrent temperature coefficient into agreement with that measured by other methods and predicted by theory. The low operating temperature and small temperature coefficient of GaAs give it an energy production advantage in warm weather.

  10. Structure and electrical characterization of gallium arsenide nanowires with different V/III ratio growth parameters

    Energy Technology Data Exchange (ETDEWEB)

    Muhammad, R.; Ahamad, R. [Sustainability Research Alliance, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia); Ibrahim, Z.; Othaman, Z. [Physic Department, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor (Malaysia)

    2014-03-05

    Gallium arsenide (GaAs) nanowires were grown vertically on GaAs(111)B substrate by gold-assisted using metal-organic chemical vapour deposition. Field-emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM) and conductivity atomic force microscopy (CAFM) analysis were carried out to investigate the effects of V/III ratio on structural properties and current-voltage changes in the wires. Results show that GaAs NWs grow preferably in the wurtzite crystal structure than zinc blende crystal structure with increasing V/III ratio. Additionally, CAFM studies have revealed that zincblende nanowires indicate ohmic characteristic compared to oscillation current occurred for wurtzite structures. The GaAs NWs with high quality structures are needed in solar cells technology for trapping energy that directly converts of sunlight into electricity with maximum capacity.

  11. Ultrafast photocurrents and terahertz radiation in gallium arsenide and carbon based nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Prechtel, Hans Leonhard

    2011-08-15

    In this thesis we developed a measurement technique based on a common pump-probe scheme and coplanar stripline circuits that enables time-resolved photocurrent measurements of contacted nanosystems with a micrometer spatial and a picosecond time resolution. The measurement technique was applied to lowtemperature grown gallium arsenide (LT-GaAs), carbon nanotubes (CNTs), graphene, and p-doped gallium arsenide (GaAs) nanowires. The various mechanisms responsible for the generation of current pulses by pulsed laser excitation were reviewed. Furthermore the propagation of the resulting electromagnetic radiation along a coplanar stripline circuit was theoretically and numerically treated. The ultrafast photocurrent response of low-temperature grown GaAs was investigated. We found two photocurrent pulses in the time-resolved response. We showed that the first pulse is consistent with a displacement current pulse. We interpreted the second pulse to result from a transport current process. We further determined the velocity of the photo-generated charge carriers to exceed the drift, thermal and quantum velocities of single charge carriers. Hereby, we interpreted the transport current pulse to stem from an electron-hole plasma excitation. We demonstrated that the photocurrent response of CNTs comprises an ultrafast displacement current and a transport current. The data suggested that the photocurrent is finally terminated by the recombination lifetime of the charge carriers. To the best of our knowledge, we presented in this thesis the first recombination lifetime measurements of contacted, suspended, CVD grown CNT networks. In addition, we studied the ultrafast photocurrent dynamics of freely suspended graphene contacted by metal electrodes. At the graphene-metal interface, we demonstrated that built-in electric fields give rise to a photocurrent with a full-width-half-maximum of a few picoseconds and that a photo-thermoelectric effect generates a current with a decay time

  12. Thermal conductivity and Seebeck coefficients of icosahedral boron arsenide films on silicon carbide

    International Nuclear Information System (INIS)

    The thermal conductivity of icosahedral boron arsenide (B12As2) films grown on (0001) 6H-SiC substrates by chemical vapor deposition was studied by the 3ω technique. The room temperature thermal conductivity decreased from 27.0 to 15.3 W/m K as the growth temperature was decreased from 1450 to 1275 deg. C. This is mainly attributed to the differences in the impurity concentration and microstructure, determined from secondary ion mass spectrometry and high resolution transmission electron microscopy, respectively. Callaway's theory was applied to calculate the temperature-dependent thermal conductivity, and the results are in good agreement with the experimental data. Seebeck coefficients were determined as 107 μV/K and 136 μV/K for samples grown at 1350 deg. C with AsH3/B2H6 flow ratio equals to 1:1 and 3:5, respectively.

  13. Cryogenic ultra-low power dissipation operational amplifiers with GaAs JFETs

    Science.gov (United States)

    Hibi, Yasunori; Matsuo, Hiroshi; Ikeda, Hirokazu; Fujiwara, Mikio; Kang, Lin; Chen, Jian; Wu, Peiheng

    2016-01-01

    To realize a multipixel camera for astronomical observation, we developed cryogenic multi-channel readout systems using gallium arsenide junction field-effect transistor (GaAs JFET) integrated circuits (ICs). Based on our experience with these cryogenic ICs, we designed, manufactured, and demonstrated operational amplifiers requiring four power supplies and two voltage sources. The amplifiers operate at 4.2 K with an open-loop gain of 2000. The gain-bandwidth product can expect 400 kHz at a power dissipation of 6 μW. In performance evaluations, the input-referred voltage noise was 4 μVrms/Hz0.5 at 1 Hz and 30 nVrms/Hz0.5 at 10 kHz, respectively. The noise power spectrum density was of type 1/f and extended to 10 kHz.

  14. Single Electron Transistor: Applications & Problems

    Directory of Open Access Journals (Sweden)

    Om Kumar

    2010-12-01

    Full Text Available The goal of this paper is to review in brief the basic physics of nano electronic device single-electron transistor [SET] as well as prospective applications and problems in their applications. SET functioning based on the controllable transfer of single electrons between small conducting "islands". The device properties dominated by the quantum mechanical properties of matter and provide new characteristics coulomb oscillation, coulomb blockade that is helpful in a number of applications. SET is able to shear domain with silicon transistor in near future and enhance the device density. Recent research in SET gives new ideas which are going to revolutionize the random access memory and digital data storage technologies.

  15. Principles of an atomtronic transistor

    Science.gov (United States)

    Caliga, Seth C.; Straatsma, Cameron J. E.; Zozulya, Alex A.; Anderson, Dana Z.

    2016-01-01

    A semiclassical formalism is used to investigate the transistor-like behavior of ultracold atoms in a triple-well potential. Atom current flows from the source well, held at fixed chemical potential and temperature, into an empty drain well. In steady-state, the gate well located between the source and drain is shown to acquire a well-defined chemical potential and temperature, which are controlled by the relative height of the barriers separating the three wells. It is shown that the gate chemical potential can exceed that of the source and have a lower temperature. In electronics terminology, the source-gate junction can be reverse-biased. As a result, the device exhibits regimes of negative resistance and transresistance, indicating the presence of gain. Given an external current input to the gate, transistor-like behavior is characterized both in terms of the current gain, which can be greater than unity, and the power output of the device.

  16. Principles of an atomtronic transistor

    CERN Document Server

    Caliga, Seth C; Zozulya, Alex A; Anderson, Dana Z

    2015-01-01

    A semiclassical formalism is used to investigate the transistor-like behavior of ultracold atoms in a triple-well potential. Atom current flows from the source well, held at fixed chemical potential and temperature, into an empty drain well. In steady-state, the gate well located between the source and drain is shown to acquire a well-defined chemical potential and temperature, which are controlled by the relative height of the barriers separating the three wells. It is shown that the gate chemical potential can exceed that of the source and have a lower temperature. In electronics terminology, the source-gate junction can be reverse-biased. As a result, the device exhibits regimes of negative resistance and transresistance, indicating the presence of gain. Given an external current input to the gate, transistor-like behavior is characterized both in terms of the current gain, which can be greater than unity, and the power output of the device.

  17. Black phosphorus nonvolatile transistor memory

    Science.gov (United States)

    Lee, Dain; Choi, Yongsuk; Hwang, Euyheon; Kang, Moon Sung; Lee, Seungwoo; Cho, Jeong Ho

    2016-04-01

    We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (104 s), and cyclic endurance (1000 cycles).We demonstrated nanofloating gate transistor memory devices (NFGTMs) using mechanically-exfoliated few-layered black phosphorus (BP) channels and gold nanoparticle (AuNPs) charge trapping layers. The resulting BP-NFGTMs exhibited excellent memory performances, including the five-level data storage, large memory window (58.2 V), stable retention (104 s), and cyclic endurance (1000 cycles). Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr02078j

  18. Single-transistor-clocked flip-flop

    Science.gov (United States)

    Zhao, Peiyi; Darwish, Tarek; Bayoumi, Magdy

    2005-08-30

    The invention provides a low power, high performance flip-flop. The flip-flop uses only one clocked transistor. The single clocked transistor is shared by the first and second branches of the device. A pulse generator produces a clock pulse to trigger the flip-flop. In one preferred embodiment the device can be made as a static explicit pulsed flip-flop which employs only two clocked transistors.

  19. Organic field-effect transistors

    Czech Academy of Sciences Publication Activity Database

    Wang, Geng; Nešpůrek, Stanislav; Zhivkov, I.; Sworakowski, J.; Yakushi, K.

    Lanškroun : IMAPS, Brno University of Technology, 2004 - (Šikula, J.), s. 169-174 ISBN 80-239-2835-X. [European Microelectronics and Packaging Symposium /3./. Prague (CZ), 16.06.2004-18.06.2004] R&D Projects: GA MŠk ME 558 Institutional research plan: CEZ:AV0Z4050913 Keywords : field-effect transistor * phthalocyanine * photoinduced field-effect Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

  20. Transistor oscillator and amplifier grids

    OpenAIRE

    Weikle, Robert M., II; Kim, Moonil; Hacker, Jonathan B.; De Lisio, Michael P.; Popvić, Zoya B.; Rutledge, David B.

    1992-01-01

    Although quasi-optical techniques are applicable to a large variety of solid-state devices, special attention is given to transistors, which are attractive because they can be used as either amplifiers or oscillators. Experimental results for MESFET bar-grid and planar grid oscillators are presented. A MESFET grid amplifier that receives only vertically polarized waves at the input and radiates horizontally polarized waves at the output is discussed. These planar grids can be scaled for opera...

  1. In-Plane Electronic Anisotropy of Underdoped ___122___ Fe-Arsenide Superconductors Revealed by Measurements of Detwinned Single Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Fisher, Ian Randal

    2012-05-08

    The parent phases of the Fe-arsenide superconductors harbor an antiferromagnetic ground state. Significantly, the Neel transition is either preceded or accompanied by a structural transition that breaks the four fold symmetry of the high-temperature lattice. Borrowing language from the field of soft condensed matter physics, this broken discrete rotational symmetry is widely referred to as an Ising nematic phase transition. Understanding the origin of this effect is a key component of a complete theoretical description of the occurrence of superconductivity in this family of compounds, motivating both theoretical and experimental investigation of the nematic transition and the associated in-plane anisotropy. Here we review recent experimental progress in determining the intrinsic in-plane electronic anisotropy as revealed by resistivity, reflectivity and ARPES measurements of detwinned single crystals of underdoped Fe arsenide superconductors in the '122' family of compounds.

  2. About some methods of obtaining of cheap gallium arsenide photo converters and solar batteries on their base

    International Nuclear Information System (INIS)

    The article presents the talk on some methods of obtaining cheap gallium arsenide photo-converters and solar batteries on their basis given at the International Workshop on applied solar energy held in Tashkent (Uzbekistan) in June 1997. The technology elaborated permits to obtain solar cells with efficiency of photo-conversion up to 20%. The electrical and photoelectrical properties of obtained cells were investigated. The elaborated solar cells are used in portable devices working in field conditions. (A.A.D.)

  3. Ultrasmall transistor-based light sources

    DEFF Research Database (Denmark)

    With Jensen, Per Baunegaard; Tavares, Luciana; Kjelstrup-Hansen, Jakob;

    Dette projekt fokuserer på at udvikle transistor baserede nanofiber lyskilder med det overordnede mål at udvikle effektive og nano skalerede flerfarvede lyskilder integreret on-chip.......Dette projekt fokuserer på at udvikle transistor baserede nanofiber lyskilder med det overordnede mål at udvikle effektive og nano skalerede flerfarvede lyskilder integreret on-chip....

  4. Operation and modeling of the MOS transistor

    CERN Document Server

    Tsividis, Yannis

    2011-01-01

    Operation and Modeling of the MOS Transistor has become a standard in academia and industry. Extensively revised and updated, the third edition of this highly acclaimed text provides a thorough treatment of the MOS transistor - the key element of modern microelectronic chips.

  5. Transistor h parameter conversion slide rule

    Science.gov (United States)

    Brantner, R. E.

    1967-01-01

    Slide rule enables the ready conversion of transistor h parameters from one form to another and reduces calculation time by a factor of 5 to 10. The scales are selected to cover all ranges of each parameter that will normally exist for any transistor, and answers are given in the correct order of magnitude, making powers-of-ten calculations unnecessary.

  6. Ferroelectric transistor memory arrays on flexible foils

    NARCIS (Netherlands)

    Breemen, A. van; Kam, B.; Cobb, B.; Rodriguez, F.G.; Heck, G. van; Myny, K.; Marrani, A.; Vinciguerra, V.; Gelinck, G.H.

    2013-01-01

    In this paper, we successfully fabricated and operated passive matrix P(VDF-TrFE) transistor arrays, i.e. memory arrays in which no pass-transistors or other additional electronic components are used. Because of the smaller cell, a higher integration density is possible. We demonstrate arrays up to

  7. Thermo-chemical properties and electrical resistivity of Zr-based arsenide chalcogenides

    Directory of Open Access Journals (Sweden)

    A. Schlechte, R. Niewa, M. Schmidt, G. Auffermann, Yu. Prots, W. Schnelle, D. Gnida, T. Cichorek, F. Steglich and R. Kniep

    2007-01-01

    Full Text Available Ternary phases in the systems Zr–As–Se and Zr–As–Te were studied using single crystals of ZrAs1.40(1Se0.50(1 and ZrAs1.60(2Te0.40(1 (PbFCl-type of structure, space group P4/nmm as well as ZrAs0.70(1Se1.30(1 and ZrAs0.75(1Te1.25(1 (NbPS-type of structure, space group Immm. The characterization covers chemical compositions, crystal structures, homogeneity ranges and electrical resistivities. At 1223 K, the Te-containing phases can be described with the general formula ZrAsxTe2−x, with 1.53(1≤x≤1.65(1 (As-rich and 0.58(1≤x≤0.75(1 (Te-rich. Both phases are located directly on the tie-line between ZrAs2 and ZrTe2, with no indication for any deviation. Similar is true for the Se-rich phase ZrAsxSe2−x with 0.70(1≤x≤0.75(1. However, the compositional range of the respective As-rich phase ZrAsx−ySe2−x (0.03(1≤y≤0.10(1; 1.42(1≤x≤1.70(1 is not located on the tie-line ZrAs2–ZrSe2, and exhibits a triangular region of existence with intrinsic deviation of the composition towards lower non-metal contents. Except for ZrAs0.75Se1.25, from the homogeneity range of the Se-rich phase, all compounds under investigation show metallic characteristics of electrical resistivity at temperatures >20 K. Related uranium and thorium arsenide selenides display a typical magnetic field-independent rise of the resistivity towards lower temperatures, which has been explained by a non-magnetic Kondo effect. However, a similar observation has been made for ZrAs1.40Se0.50, which, among the Zr-based arsenide chalcogenides, is the only system with a large concentration of intrinsic defects in the anionic substructure.

  8. BN / Graphene / BN RF Transistors

    Science.gov (United States)

    Wang, Han; Taychatanapat, Thiti; Hsu, Allen; Jarillo-Herrero, Pablo; Palacios, Tomas

    2011-03-01

    In this work we demonstrate the first BN/graphene/BN transistor for high frequency RF applications. This sandwich structure allows a significant improvement in the mobility of graphene, which reaches more than 18,000 cm2 /Vs at room temperature. Graphene field effect transistors (GFETs) have been fabricated with LDS = 800 nm and LG = 300 nm. The minimum conduction point of these devices is very close to zero, a result of the negligible substrate doping to the graphene. A current density in excess of 1 A/mm and DC transconductance above 200 mS/mm are achieved for both electron and hole conductions. RF characterization is performed for the first time on this device structure and initial results show a current-gain cut-off frequency fT = 10 GHz. These experimental results have been combined with simulations of the small-signal model to study the scaling potential of these GFETs for high frequency applications. The impact of the access resistances (Rs , Rd) , the capacitances (Cgs , Cgd , Cds) , and the transconductance (g m) on the frequency performance of the GFETs has also been studied. Finally, the fabricated devices have been compared to GFETs fabricated with Si O2 substrate and Al 2 O3 gate dielectrics. The improved performance obtained by the BN/graphene/BN structure is very promising to enable the next generation of high frequency RF electronics.

  9. Structural anomalies in undoped Gallium Arsenide observed in high resolution diffraction imaging with monochromatic synchrotron radiation

    Science.gov (United States)

    Steiner, B.; Kuriyama, M.; Dobbyn, R. C.; Laor, U.; Larson, D.; Brown, M.

    1988-01-01

    Novel, streak-like disruption features restricted to the plane of diffraction have recently been observed in images obtained by synchrotron radiation diffraction from undoped, semi-insulating gallium arsenide crystals. These features were identified as ensembles of very thin platelets or interfaces lying in (110) planes, and a structural model consisting of antiphase domain boundaries was proposed. We report here the other principal features observed in high resolution monochromatic synchrotron radiation diffraction images: (quasi) cellular structure; linear, very low-angle subgrain boundaries in (110) directions, and surface stripes in a (110) direction. In addition, we report systematic differences in the acceptance angle for images involving various diffraction vectors. When these observations are considered together, a unifying picture emerges. The presence of ensembles of thin (110) antiphase platelet regions or boundaries is generally consistent not only with the streak-like diffraction features but with the other features reported here as well. For the formation of such regions we propose two mechanisms, operating in parallel, that appear to be consistent with the various defect features observed by a variety of techniques.

  10. Resonant photo-thermal modification of vertical gallium arsenide nanowires studied using Raman spectroscopy

    Science.gov (United States)

    Walia, Jaspreet; Boulanger, Jonathan; Dhindsa, Navneet; LaPierre, Ray; (Shirley Tang, Xiaowu; Saini, Simarjeet S.

    2016-06-01

    Gallium arsenide nanowires have shown considerable promise for use in applications in which the absorption of light is required. When the nanowires are oriented vertically, a considerable amount of light can be absorbed, leading to significant heating effects. Thus, it is important to understand the threshold power densities that vertical GaAs nanowires can support, and how the nanowire morphology is altered under these conditions. Here, resonant photo-thermal modification of vertical GaAs nanowires was studied using both Raman spectroscopy and electron microscopy techniques. Resonant waveguiding, and subsequent absorption of the excited optical mode reduces the irradiance vertical GaAs nanowires can support relative to horizontal ones, by three orders of magnitude before the onset of structural changes occur. A power density of only 20 W mm‑2 was sufficient to induce local heating in the nanowires, resulting in the formation of arsenic species. Upon further increasing the power, a hollow nanowire morphology was realized. These findings are pertinent to all optical applications and spectroscopic measurements involving vertically oriented GaAs nanowires. Understanding the optical absorption limitations, and the effects of exceeding these limitations will help improve the development of all III–V nanowire devices.

  11. Monopole Charge Domain in High-Gain Gallium Arsenide Photoconductive Switches

    Institute of Scientific and Technical Information of China (English)

    施卫; 陈二柱; 张显斌; 李琦

    2002-01-01

    Considering that semi-insulating gallium arsenide photoconductive switches can be triggered into the high gain mode and no reliable theories can account for the observed transient characteristics, we propose the monopole charge domain model to explain the peculiar switching phenomena occurring in the high gain mode and we discuss the requirements for the lock-on switching. During operation on this mode, the applied field across the switch and the lock-on field are all larger than the Gunn threshold field. Our developed monopole charge domain is based on the transferred-electron effect, but the domain is only composed of large numbers of electrons piled up due to the negative differential mobility. Using the model and taking the physical mechanism of the avalanche impact ionization and recombination radiation into consideration, we interpret the typical phenomena of the lock-on effect, such as the time delay between the beginning of optical illumination and turning-on of the switch, and the conduction mechanism of the sustaining phase. Under different conditions of bias field intensity and incident light energy, the time delay of the switching is calculated. The results show that the physical mechanisms of impact ionization and recombination radiation occurring in the monopole charge domain are responsible for the lock-on switching.

  12. Discovery of a Weyl fermion state with Fermi arcs in niobium arsenide

    Science.gov (United States)

    Xu, Su-Yang; Alidoust, Nasser; Belopolski, Ilya; Yuan, Zhujun; Bian, Guang; Chang, Tay-Rong; Zheng, Hao; Strocov, Vladimir N.; Sanchez, Daniel S.; Chang, Guoqing; Zhang, Chenglong; Mou, Daixiang; Wu, Yun; Huang, Lunan; Lee, Chi-Cheng; Huang, Shin-Ming; Wang, Baokai; Bansil, Arun; Jeng, Horng-Tay; Neupert, Titus; Kaminski, Adam; Lin, Hsin; Jia, Shuang; Zahid Hasan, M.

    2015-09-01

    Three types of fermions play a fundamental role in our understanding of nature: Dirac, Majorana and Weyl. Whereas Dirac fermions have been known for decades, the latter two have not been observed as any fundamental particle in high-energy physics, and have emerged as a much-sought-out treasure in condensed matter physics. A Weyl semimetal is a novel crystal whose low-energy electronic excitations behave as Weyl fermions. It has received worldwide interest and is believed to open the next era of condensed matter physics after graphene and three-dimensional topological insulators. However, experimental research has been held back because Weyl semimetals are extremely rare in nature. Here, we present the experimental discovery of the Weyl semimetal state in an inversion-symmetry-breaking single-crystalline solid, niobium arsenide (NbAs). Utilizing the combination of soft X-ray and ultraviolet photoemission spectroscopy, we systematically study both the surface and bulk electronic structure of NbAs. We experimentally observe both the Weyl cones in the bulk and the Fermi arcs on the surface of this system. Our ARPES data, in agreement with our theoretical band structure calculations, identify the Weyl semimetal state in NbAs, which provides a real platform to test the potential of Weyltronics.

  13. A stress gettering mechanism in semi-insulating, copper-contaminated gallium arsenide

    Science.gov (United States)

    Kang, Nam Soo; Zirkle, Thomas E.; Schroder, Dieter K.

    1992-07-01

    We have demonstrated a stress gettering mechanism in semi-insulating, copper-contaminated gallium arsenide (GaAs) using cathodoluminescence (CL), thermally stimulated current spectroscopy (TSC), and low temperature Fourier transform infrared spectroscopy (FTIR). Cathodoluminescence shows a local gettering effect around dislocation cores in bulk semi-insulating GaAs qualitatively. This gettering result was confirmed by low temperature FTIR data, which show absorption features resulting from the transition of electrons from the valence band to copper levels. The energy level of each absorption shoulder corresponds to the various copper levels in GaAs. After gettering, the absorption depth at each shoulder decreases. Thermally stimulated current measurements show changes after copper doping. The characteristic returns to that of uncontaminated GaAs after gettering. On the basis of these qualitative and quantitative data, we conclude that copper was gettered, and we propose a stress gettering mechanism in semi-insulating, copper-contaminated GaAs on the basis of dislocation cores acting as localized gettering sites.

  14. Ab-initio Electronic, Transport and Related Properties of Zinc Blende Boron Arsenide (zb-BAs)

    Science.gov (United States)

    Nwigboji, Ifeanyi H.; Malozovsky, Yuriy; Bagayoko, Diola

    We present results from ab-initio, self-consistent density functional theory (DFT) calculations of electronic, transport, and bulk properties of zinc blende boron arsenide (zb-BAs). We utilized a local density approximation (LDA) potential and the linear combination of atomic orbital (LCAO) formalism. Our computational technique follows the Bagayoko, Zhao, and Williams method, as enhanced by Ekuma and Franklin. Our results include electronic energy bands, densities of states, and effective masses. We explain the agreement between these findings, including the indirect band gap, and available, corresponding, experimental ones. This work confirms the capability of DFT to describe accurately properties of materials, provided the computations adhere to the conditions of validity of DFT [AIP Advances, 4, 127104 (2014)]. Acknowledgments: This work was funded in part by the National Science Foundation (NSF) and the Louisiana Board of Regents, through LASiGMA [Award Nos. EPS- 1003897, NSF (2010-15)-RII-SUBR] and NSF HRD-1002541, the US Department of Energy - National, Nuclear Security Administration (NNSA) (Award No. DE- NA0002630), LaSPACE, and LONI-SUBR.

  15. High-temperature optically activated GaAs power switching for aircraft digital electronic control

    Science.gov (United States)

    Berak, J. M.; Grantham, D. H.; Swindal, J. L.; Black, J. F.; Allen, L. B.

    1983-01-01

    Gallium arsenide high-temperature devices were fabricated and assembled into an optically activated pulse-width-modulated power control for a torque motor typical of the kinds used in jet engine actuators. A bipolar heterojunction phototransistor with gallium aluminum arsenide emitter/window, a gallium arsenide junction field-effect power transistor and a gallium arsenide transient protection diode were designed and fabricated. A high-temperature fiber optic/phototransistor coupling scheme was implemented. The devices assembled into the demonstrator were successfully tested at 250 C, proving the feasibility of actuator-located switching of control power using optical signals transmitted by fibers. Assessments of the efficiency and technical merits were made for extension of this high-temperature technology to local conversion of optical power to electrical power and its control at levels useful for driving actuators. Optical power sources included in the comparisons were an infrared light-emitting diode, an injection laser diode, tungsten-halogen lamps and arc lamps. Optical-to-electrical power conversion was limited to photovoltaics located at the actuator. Impedance matching of the photovoltaic array to the load was considered over the full temperature range, -55 C to 260 C. Loss of photovoltaic efficiency at higher temperatures was taken into account. Serious losses in efficiency are: (1) in the optical source and the cooling which they may require in the assumed 125 C ambient, (2) in the decreased conversion efficiency of the gallium arsenide photovoltaic at 260 C, and (3) in impedance matching. Practical systems require improvements in these areas.

  16. Organic and polymer transistors for electronics

    Directory of Open Access Journals (Sweden)

    Ananth Dodabalapur

    2006-04-01

    Full Text Available Some of the major application areas for organic and polymeric transistors are reviewed. Organic complementary devices are promising on account of their lower power dissipation and ease of circuit design. The first organic large-scale integrated circuits have been implemented with this circuit approach. Organic transistor backplanes are ideally suited for electronic paper applications and other display schemes. Low-cost and other processing advantages, as well as improving performance, have led to organic-based radio frequency identification tag development. The chemical interaction between various organic and polymer semiconductors can be exploited in chemical and biological sensors based upon organic transistors.

  17. Transistors using crystalline silicon devices on glass

    Science.gov (United States)

    McCarthy, Anthony M.

    1995-01-01

    A method for fabricating transistors using single-crystal silicon devices on glass. This method overcomes the potential damage that may be caused to the device during high voltage bonding and employs a metal layer which may be incorporated as part of the transistor. This is accomplished such that when the bonding of the silicon wafer or substrate to the glass substrate is performed, the voltage and current pass through areas where transistors will not be fabricated. After removal of the silicon substrate, further metal may be deposited to form electrical contact or add functionality to the devices. By this method both single and gate-all-around devices may be formed.

  18. Protonic transistors from thin reflecting films

    International Nuclear Information System (INIS)

    Ionic transistors from organic and biological materials hold great promise for bioelectronics applications. Thus, much research effort has focused on optimizing the performance of these devices. Herein, we experimentally validate a straightforward strategy for enhancing the high to low current ratios of protein-based protonic transistors. Upon reducing the thickness of the transistors’ active layers, we increase their high to low current ratios 2-fold while leaving the other figures of merit unchanged. The measured ratio of 3.3 is comparable to the best values found for analogous devices. These findings underscore the importance of the active layer geometry for optimum protonic transistor functionality

  19. Pass-transistor very large scale integration

    Science.gov (United States)

    Maki, Gary K. (Inventor); Bhatia, Prakash R. (Inventor)

    2004-01-01

    Logic elements are provided that permit reductions in layout size and avoidance of hazards. Such logic elements may be included in libraries of logic cells. A logical function to be implemented by the logic element is decomposed about logical variables to identify factors corresponding to combinations of the logical variables and their complements. A pass transistor network is provided for implementing the pass network function in accordance with this decomposition. The pass transistor network includes ordered arrangements of pass transistors that correspond to the combinations of variables and complements resulting from the logical decomposition. The logic elements may act as selection circuits and be integrated with memory and buffer elements.

  20. Basic matrix algebra and transistor circuits

    CERN Document Server

    Zelinger, G

    1963-01-01

    Basic Matrix Algebra and Transistor Circuits deals with mastering the techniques of matrix algebra for application in transistors. This book attempts to unify fundamental subjects, such as matrix algebra, four-terminal network theory, transistor equivalent circuits, and pertinent design matters. Part I of this book focuses on basic matrix algebra of four-terminal networks, with descriptions of the different systems of matrices. This part also discusses both simple and complex network configurations and their associated transmission. This discussion is followed by the alternative methods of de

  1. Interface engineering in organic transistors

    Directory of Open Access Journals (Sweden)

    Yeong Don Park

    2007-03-01

    Full Text Available Recent technological advances in organic field-effect transistors (OFETs have triggered intensive research into the molecular and mesoscale structures of organic semiconductor films that determine their charge-transport characteristics. Since the molecular structure and morphology of an organic semiconductor are largely determined by the properties of the interface between the organic film and the insulator, a great deal of research has focused on interface engineering. We review recent progress in interface engineering for the fabrication of high-performance OFETs and, in particular, engineering of the interfaces between semiconductors and insulators. The effects of interfacial characteristics on the molecular and mesoscale structures of π-conjugated molecules and the performance of OFET devices are discussed.

  2. Quantum dot field effect transistors

    Directory of Open Access Journals (Sweden)

    Frederik Hetsch

    2013-09-01

    Full Text Available Solution processed colloidal semiconductor quantum dots offer a high potential for decreasing costs and expanding versatility of many electronic and optoelectronic devices. Initially used as a research tool to study charge carrier mobilities in closely packed quantum dot thin films, field effect transistors with quantum dots as the active layer have recently experienced a breakthrough in performance (achievement of mobilities higher than 30 cm2 V−1 s−1 as a result of a proper choice of surface ligands and/or improved chemical treatment of the nanoparticle films during device processing. Here we review these innovative developments and the continuing work that may soon lead to commercial grade electronic components.

  3. Lateral power transistors in integrated circuits

    CERN Document Server

    Erlbacher, Tobias

    2014-01-01

    This book details and compares recent advancements in the development of novel lateral power transistors (LDMOS devices) for integrated circuits in power electronic applications. It includes the state-of-the-art concept of double-acting RESURF topologies.

  4. ARC Filters with Diamond Transistors and Buffers

    OpenAIRE

    T. Dostal

    1998-01-01

    Active RC first and second order filters using diamond transistors (voltage controlled current sources) and voltage diamond buffers (voltage controlled voltage sources) are given in this paper. Circuits are simulated and experimentally compared.

  5. Multiscale simulation of carbon nanotube transistors

    OpenAIRE

    Maneux, Cristell; Roche, Stephan

    2013-01-01

    In recent years, the understanding and accurate simulation of carbon nanotube-based transistors has become very challenging. Conventional simulation tools of microelectronics are necessary to predict the performance and use of nanotube transistors and circuits, but the models need to be refined to properly describe the full complexity of such novel type of devices at the nanoscale. Indeed, many issues such as contact resistance, low dimensional electrostatics and screening effects, demand for...

  6. Basic characteristics of the avalanche transistor

    International Nuclear Information System (INIS)

    The avalanche transistor is a useful device for a short-pulse generator of the thermionic electron-gun. However, some properties of the transistor have not been clear experimentally until now. In this report the following properties are presented: the thermal characteristics of the primary breakdown voltage, variations of the output pulse waveform according to the power supply voltage, and the estimated V-I curve of the secondary breakdown voltage. (author)

  7. Stable Transistors in Hydrogenated Amorphous Silicon

    OpenAIRE

    J. M. Shannon

    2004-01-01

    Thin-film field-effect transistors in hydrogenated amorphous silicon are notoriously unstable due to the formation of silicon dangling bond trapping states in the accumulated channel region during operation. Here, we show that by using a source-gated transistor a major improvement in stability is obtained. This occurs because the electron quasi-Fermi level is pinned near the center of the band in the active source region of the device and strong accumulation of electrons is prevented. The use...

  8. A single-transistor silicon synapse

    OpenAIRE

    Diorio, Chris; Hasler, Paul; Minch, Bradley A.; Mead, Carver A.

    1996-01-01

    We have developed a new floating-gate silicon MOS transistor for analog learning applications. The memory storage is nonvolatile; hot-electron injection and electron tunneling permit bidirectional memory updates. Because these updates depend on both the stored memory value and the transistor terminal voltages, the synapse can implement a learning function. We have derived a memory-update rule from the physics of the tunneling and injection processes, and have investigated synapse learning in ...

  9. Magnetism of unconventional superconductors using the example of ruthenate and iron arsenide compounds

    International Nuclear Information System (INIS)

    The focus of this work lies on the magnetism in unconventional superconductors. The big question in this kind of superconductors is as magnetism influences the transition in the superconducting phase. During this thesis two different classes of compounds were investigated: iron-arsenides and ruthenates. The compounds of both have similarities to the famous cuprates. For the investigations of iron-arsenides the crystal structures of LiFeAs and Li0.95Fe0.05As were determined first. Afterwards the magnetic moments of both compounds as function of temperature and magnetic field and the spin density were measured. It was found out that the pure compound is a spin-singlet superconductor. The spin density is placed mainly at the iron atoms and can be described with the multipol-model. Additionally an impurity by iron atoms at interstitial places were found. For the non-stoichiometric compound the high magnetic moment below 156K could be confirmed. But the mail sin density is located at the position of the excess iron atom at interstitial positions. This positions changes with the magnetic field. This points to the fact that the high magnetic moment comes from the additional iron atoms which are formed in clusters. In addition, the crystal structure of REFeAsO (with RE=Ce, Pr and Nd) as a function of the temperature was examined. An orthorhombic transition was measured at 150 K. The precursors (which are also found in LaFeAsO) were seen. The strengthens of these precursors decreases with increasing size of the rare-earth atoms. For the ruthenates macroscopic investigations of the susceptibility and the electric resistivity of Ca3Ru0.9Ti0.1O7 were done. Moreover, the influence from the transition of the crystal structure was investigated. It turned out that the doping with titanium stabilizes the isolating phase which was already found in the pure connection. A jump by three scales was found in the electric resistivity and a change in the crystal structure (without changing

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

    International Nuclear Information System (INIS)

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

  11. Coherent detection of THz waves based on THz-induced time-resolved luminescence quenching in bulk gallium arsenide.

    Science.gov (United States)

    Chu, Zheng; Liu, Jinsong; Wang, Kejia

    2012-05-01

    A kind of photoluminescence quenching, in which the time-resolved photoluminescence is modulated by a THz pulse, has been theoretically investigated by performing the ensemble Monte Carlo method in bulk gallium arsenide (GaAs) at room temperature. The quenching ratio could reach up to 50% under a strong THz field (100  kV/cm). The range in which luminescence quenching is linearly proportional to the THz field could be over 60  kV/cm. On the basis of these results, a principle for THz modulation and coherent detection is proposed. PMID:22555695

  12. Retinal alterations produced by low level gallium arsenide laser exposure. Interim report, 1 May--31 December 1976

    Energy Technology Data Exchange (ETDEWEB)

    Beatrice, E.S.; Lund, D.J.; Talsma, D.M.

    1977-02-01

    The retinas of rhesus monkeys were subjected to irradiation by a prototype gallium arsenide (GaAs) laser training device. The laser device operated at 1600 Hz (pulse repetition frequency mode) or 132 Hz (pulse code mode) with nominal peak pulse power of 1 watt and 10 watts. Exposure durations ranged from 1.0 sec to 90 sec. The tissue reaction at the exposure site was characterized by the development of a pale gray clouding within 10 sec of initiation of the exposure. The nature of the retinal change could not be determined by ophthalmoscopic, histologic, or flourescein leakage techniques.

  13. Temas de Física para Ingeniería: El transistor de unión

    OpenAIRE

    Beléndez Vázquez, Augusto; Pastor Antón, Carlos; Martín García, Agapito

    1990-01-01

    El transistor de unión bipolar. Tensiones y corrientes en el transistor. El transistor como amplificador. El transistor como conmutador. Transistores unipolares o de efecto de campo. El tiristor. Microelectrónica y circuitos integrados.

  14. Complementary transistor-transistor logic /CTTL/ - An approach to high-speed micropower logic.

    Science.gov (United States)

    Stehlin, R. A.; Niemann, G. W.

    1972-01-01

    Description of a new approach to micropower integrated circuits that is called complementary transistor-transistor logic (CTTL). This logic combines the inherent low standby power of a complementary inverter with the high speed of the TTL-type input. Results of monolithic fabricated circuits are presented. These circuits are shown to be equally adaptable to hybrid and discrete circuitry.

  15. Revealing the optoelectronic and thermoelectric properties of the Zintl quaternary arsenides ACdGeAs{sub 2} (A = K, Rb)

    Energy Technology Data Exchange (ETDEWEB)

    Azam, Sikander; Khan, Saleem Ayaz [New Technologies—Research Center, University of West Bohemia, Univerzitni 8, 306 14 Pilsen (Czech Republic); Goumri-Said, Souraya, E-mail: Souraya.Goumri-Said@chemistry.gatech.edu [School of Chemistry and Biochemistry and Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, GA 30332-0400 (United States)

    2015-10-15

    Highlights: • Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) are chalcopyrite and semiconductors. • Their direct band gap is suitable for PV, optolectronic and thermoelectric applications. • Combination of DFT and Boltzmann transport theory is employed. • The present arsenides are found to be covalent materials. - Abstract: Chalcopyrite semiconductors have attracted much attention due to their potential implications in photovoltaic and thermoelectric applications. First principle calculations were performed to investigate the electronic, optical and thermoelectric properties of the Zintl tetragonal phase ACdGeAs{sub 2} (A = K, Rb) using the full potential linear augmented plane wave method and the Engle–Vosko GGA (EV–GGA) approximation. The present compounds are found semiconductors with direct band gap and covalent bonding character. The optical transitions are investigated via the dielectric function (real and imaginary parts) along with other related optical constants including refractive index, reflectivity and energy-loss spectrum. Combining results from DFT and Boltzmann transport theory, we reported the thermoelectric properties such as the Seebeck’s coefficient, electrical and thermal conductivity, figure of merit and power factor as function of temperatures. The present chalcopyrite Zintl quaternary arsenides deserve to be explored for their potential applications as thermoelectric materials and for photovoltaic devices.

  16. Revealing the optoelectronic and thermoelectric properties of the Zintl quaternary arsenides ACdGeAs2 (A = K, Rb)

    International Nuclear Information System (INIS)

    Highlights: • Zintl tetragonal phase ACdGeAs2 (A = K, Rb) are chalcopyrite and semiconductors. • Their direct band gap is suitable for PV, optolectronic and thermoelectric applications. • Combination of DFT and Boltzmann transport theory is employed. • The present arsenides are found to be covalent materials. - Abstract: Chalcopyrite semiconductors have attracted much attention due to their potential implications in photovoltaic and thermoelectric applications. First principle calculations were performed to investigate the electronic, optical and thermoelectric properties of the Zintl tetragonal phase ACdGeAs2 (A = K, Rb) using the full potential linear augmented plane wave method and the Engle–Vosko GGA (EV–GGA) approximation. The present compounds are found semiconductors with direct band gap and covalent bonding character. The optical transitions are investigated via the dielectric function (real and imaginary parts) along with other related optical constants including refractive index, reflectivity and energy-loss spectrum. Combining results from DFT and Boltzmann transport theory, we reported the thermoelectric properties such as the Seebeck’s coefficient, electrical and thermal conductivity, figure of merit and power factor as function of temperatures. The present chalcopyrite Zintl quaternary arsenides deserve to be explored for their potential applications as thermoelectric materials and for photovoltaic devices

  17. Plasma enhanced deposition of 'silicon nitride' for use as an encapsulant for silicon ion-implanted gallium arsenide

    International Nuclear Information System (INIS)

    Silicon nitride films have been produced by plasma enhanced chemical vapour deposition using silane and ammonia as the reactant gases in a Plasma-Therm PK1250PD machine. The compositions of the films have been investigated as a function of the silane to ammonia flow rate ratio used for deposition, using infra-red transmission and Auger electron spectroscopies. These techniques indicated that the plasma deposited films were silicon-rich and contained hydrogen. The oxygen content of the films was below the detection limit of Auger electron spectroscopy implying that it was less than 1%. Silicon ion-implanted semi-insulating gallium arsenide has been annealed using an approximately 1000 A thick film of plasma deposited silicon nitride as an encapsulant. This capped annealing technique has achieved 70% activations of 4 x 1012 cm-2, 200 keV silicon implants with sheet Hall mobilities of 4000 cm2 V-1 s-1 at room temperature. Free carrier concentration and Hall mobility profiles are presented. Unimplanted semi-insulating gallium arsenide samples have also been capped annealed in the same manner and maintained a sheet resistivity of greater than 107 Ω/square after annealing. (author)

  18. Single-channel transistorized selector

    International Nuclear Information System (INIS)

    The special aim has been stability of the thresholds and standardized pulses under variations of temperature, and also interchangeability of transistors. The selector has the following specifications. Input dynamic, 100 mV to 10 V; adjustable channel width, 100 mV to 1 V; minimum resolving time, 5 μs; maximum storage of capacitor, 100000cps; linearity of capacitor, ± 1%; stability of capacitor: final information is retained to 1% after 24 hours. Tests of the selector under variations of temperature were carried out between -20o and + 55o. The following was observed: threshold variation of + 2% for a threshold of 100 mV; channel-width variation of ± 2% for a width of 100mV; stored information variation in the capacitor of ± 2%. The selector is wired on a plate of dimensions 196 x 96 mm. Consumption is 20 mA at -18V and 30 mA at + 18 V. (author)

  19. Analysis of Time Dependent Low Level Exposure to Gallium Arsenide on Blood ALAD activity, Glutathione and Lipid per oxidation levels in Rat Blood, Liver and Kidney

    Directory of Open Access Journals (Sweden)

    Braham Deo Gupta

    2015-06-01

    Full Text Available Gallium arsenide (GaAs, an intermetallic semiconductor has widespread applications in the electronic industry. GaAs has the ability to dissociate into its constitutive moieties, arsenic and gallium which might be responsible for the oxidative stress. The present study was aimed at evaluating, effect of gallium arsenide on blood ALAD activity, glutathione and lipid per oxidation levels in rat blood, liver and kidney on exposure of 1, 2 and 6 months. Result indicated that arsenic moiety in GaAs was mainly responsible for causing oxidative stress via increased TBARS levels, decreased glutathione levels in blood and tissues. We also noted the decreased activity of ALAD in rat blood on exposure to gallium arsenide. The study demonstrates that the time dependent exposure to low level gallium arsenide led to increased in lipid per oxidation, decrease glutathione level and ALAD activity which concludes that the slow release of arsenic moiety from GaAs is mainly responsible for oxidative stress in rats and exerts its toxicity in time dependent manner related to its dissolution and maximum toxicity by increasing the time period of exposure.

  20. Field effect transistors for terahertz imaging

    Energy Technology Data Exchange (ETDEWEB)

    Knap, Wojciech; Coquillat, Dominique; Teppe, Frederic; Dyakonova, Nina; Nadar, Salman; El Fatimy, Abdel [Universite Montpellier 2, CNRS, UMR 5650 et URM 5207, Montpellier (France); Valusis, Gintaras; Seliuta, Dalius; Kasalynas, Irmantas [Semiconductor Physics Institute, Vilnius (Lithuania); Lusakowski, Jerzy; Karpierz, Krzysztof; Bialek, Marcin [Institute of Experimental Physics, University of Warsaw (Poland)

    2009-12-15

    Resonant frequencies of the two-dimensional plasma in field effect transistors (FETs) increase with the reduction of the channel dimensions and can reach the terahertz (THz) range for micrometer and sub-micrometer channel lengths. Nonlinearity of the gated electron gas in the transistor channel can be used for the detection of THz radiation. The possibility of tuneable narrow band detection in sub-THz and THz range, related to plasma resonances, has been demonstrated for nanometre gate length transistors at cryogenic temperatures. At room temperatures the plasma oscillations are usually strongly damped, but field effect transistors can still operate as an efficient broadband detectors in the THz range. We present an overview of experimental results on THz detection by field effect transistors made of III-V and Si materials, The material issue is discussed and first room applications of FETs for imaging at frequencies above 1 THz are demonstrated. (copyright 2009 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  1. High Accuracy Transistor Compact Model Calibrations

    Energy Technology Data Exchange (ETDEWEB)

    Hembree, Charles E. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Mar, Alan [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Robertson, Perry J. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Typically, transistors are modeled by the application of calibrated nominal and range models. These models consists of differing parameter values that describe the location and the upper and lower limits of a distribution of some transistor characteristic such as current capacity. Correspond- ingly, when using this approach, high degrees of accuracy of the transistor models are not expected since the set of models is a surrogate for a statistical description of the devices. The use of these types of models describes expected performances considering the extremes of process or transistor deviations. In contrast, circuits that have very stringent accuracy requirements require modeling techniques with higher accuracy. Since these accurate models have low error in transistor descriptions, these models can be used to describe part to part variations as well as an accurate description of a single circuit instance. Thus, models that meet these stipulations also enable the calculation of quantifi- cation of margins with respect to a functional threshold and uncertainties in these margins. Given this need, new model high accuracy calibration techniques for bipolar junction transis- tors have been developed and are described in this report.

  2. Stretchable transistors with buckled carbon nanotube films as conducting channels

    Science.gov (United States)

    Arnold, Michael S; Xu, Feng

    2015-03-24

    Thin-film transistors comprising buckled films comprising carbon nanotubes as the conductive channel are provided. Also provided are methods of fabricating the transistors. The transistors, which are highly stretchable and bendable, exhibit stable performance even when operated under high tensile strains.

  3. Discrete transistor measuring and matching using a solid core oven

    Science.gov (United States)

    Inkinen, M.; Mäkelä, K.; Vuorela, T.; Palovuori, K.

    2013-03-01

    This paper presents transistor measurements done at a constant temperature. The aim in this research was to develop a reliable and repeatable method for measuring and searching transistor pairs with similar parameters, as in certain applications it is advantageous to use transistors from the same production batch due to the significant variability in batches from different manufacturers. Transistor manufacturing methods are well established, but due to the large variability in tolerance, not even transistors from the same manufacturing batch have identical properties. Transistors' electrical properties are also strongly temperature-dependent. Therefore, when measuring transistor properties, the temperature must be kept constant. For the measurement process, a solid-core oven providing stable temperature was implemented. In the oven, the base-to-emitter voltage (VBE) and DC-current gain (β) of 32 transistors could be measured simultaneously. The oven's temperature was controlled with a programmable thermostat, which allowed accurate constant temperature operation. The oven is formed by a large metal block with an individual chamber for each transistor to be measured. Isolation of individual transistors and the highly thermally conductive metal core structure prevent thermal coupling between transistors. The oven enables repeatable measurements, and thus measurements between different batches are comparable. In this research study, the properties of over 5000 transistors were measured and the variance of the aforementioned properties was analyzed.

  4. Superiority of p-type spin transistors

    International Nuclear Information System (INIS)

    The spintronic device that has probably stimulated the most research interest is the Datta-Das spin transistor. The mechanism behind it, called the Rashba effect, is that an applied voltage gives rise to a spin splitting. We demonstrate that the relevant spin splitting in k-space can be made more than three orders of magnitude larger for holes than for electrons at the same electric field. This is partly achieved by utilizing the frequently neglected lattice-mismatch between GaAs and AlGaAs. We design heterostructures where this efficient Rashba effect should show up. Compared to present transistors, we conclude that electron-based spin transistors will have problems in becoming competitive but hole-based ones are much more promising

  5. Optical switching of functionalized carbon nanotube transistors

    Science.gov (United States)

    Borghetti, Julien; Derycke, Vincent; Chenevier, Pascale; Filoramo, Arianna; Goffman, Marcello; Bourgoin, Jean-Philippe; Lenfant, Stephane; Vuillaume, Dominique

    2006-03-01

    Carbon Nanotube (CNT) transistors can emit or detect photons at wavelengths defined by the CNT chirality. To extend their capabilities in optoelectronics, it is important to be able to tune this wavelength independently of the CNT structure. A way to achieve such a goal is to chemically functionalize the CNT. In the present study, we demonstrate that drastic photo-induced modifications of the electrical characteristics of self-assembled CNT transistors functionalized by photoactive polymers can be achieved. We show that the polymer film acts as a wavelength dependent 'optical gate', which is much more efficient than a conventional electrostatic gate and can induce changes in conductance exceeding four orders of magnitude. The switching mechanism involves the creation and separation of photo-excited charges in the polymer, the spatial distribution and relaxation rates of which are studied taking advantage of the very high charge sensitivity of the CNT transistor.

  6. Fundamentals of nanoscaled field effect transistors

    CERN Document Server

    Chaudhry, Amit

    2013-01-01

    Fundamentals of Nanoscaled Field Effect Transistors gives comprehensive coverage of the fundamental physical principles and theory behind nanoscale transistors. The specific issues that arise for nanoscale MOSFETs, such as quantum mechanical tunneling and inversion layer quantization, are fully explored. The solutions to these issues, such as high-κ technology, strained-Si technology, alternate devices structures and graphene technology are also given. Some case studies regarding the above issues and solution are also given in the book. In summary, this book: Covers the fundamental principles behind nanoelectronics/microelectronics Includes chapters devoted to solutions tackling the quantum mechanical effects occurring at nanoscale Provides some case studies to understand the issue mathematically Fundamentals of Nanoscaled Field Effect Transistors is an ideal book for researchers and undergraduate and graduate students in the field of microelectronics, nanoelectronics, and electronics.

  7. Coherence in a cold atom photon transistor

    CERN Document Server

    Li, Weibin

    2015-01-01

    Recent experiments have realized an all-optical photon transistor using a cold atomic gas. This approach relies on electromagnetically induced transparency (EIT) in conjunction with the strong interaction among atoms excited to high-lying Rydberg states. The transistor is gated via a so-called Rydberg spinwave, in which a single Rydberg excitation is coherently shared by the whole ensemble. In its absence the incoming photon passes through the atomic ensemble by virtue of EIT while in its presence the photon is scattered rendering the atomic gas opaque. An important current challenge is to preserve the coherence of the Rydberg spinwave during the operation of the transistor, which would enable for example its coherent optical read-out and its further processing in quantum circuits. With a combined field theoretical and quantum jump approach and by employing a simple model description we investigate systematically and comprehensively how the coherence of the Rydberg spinwave is affected by photon scattering. W...

  8. Transistor Small Signal Analysis under Radiation Effects

    International Nuclear Information System (INIS)

    A Small signal transistor parameters dedicate the operation of bipolar transistor before and after exposed to gamma radiation (1 Mrad up to 5 Mrads) and electron beam(1 MeV, 25 mA) with the same doses as a radiation sources, the electrical parameters of the device are changed. The circuit Model has been discussed.Parameters, such as internal emitter resistance (re), internal base resistance, internal collector resistance (re), emitter base photocurrent (Ippe) and base collector photocurrent (Ippe). These parameters affect on the operation of the device in its applications, which work as an effective element, such as current gain (hFE≡β)degradation it's and effective parameter in the device operation. Also the leakage currents (IcBO) and (IEBO) are most important parameters, Which increased with radiation doses. Theoretical representation of the change in the equivalent circuit for NPN and PNP bipolar transistor were discussed, the input and output parameters of the two types were discussed due to the change in small signal input resistance of the two types. The emitter resistance(re) were changed by the effect of gamma and electron beam irradiation, which makes a change in the role of matching impedances between transistor stages. Also the transistor stability factors S(Ico), S(VBE) and S(β are detected to indicate the transistor operations after exposed to radiation fields. In low doses the gain stability is modified due to recombination of induced charge generated during device fabrication. Also the load resistance values are connected to compensate the effect

  9. Gigahertz frequency flexible carbon nanotube transistors

    Science.gov (United States)

    Chimot, N.; Derycke, V.; Goffman, M. F.; Bourgoin, J. P.; Happy, H.; Dambrine, G.

    2007-10-01

    We investigate the high frequency performances of flexible field-effect transistors based on carbon nanotubes. A large density of mostly aligned carbon nanotubes deposited on a flexible substrate by dielectrophoresis serves as the channel. The transistors display a constant transconductance up to at least 6GHz and a current gain cutoff frequency (fT) as high as 1GHz at VDS=-700mV. Bending tests show that the devices can withstand a high degree of flexion characterized by a constant transconductance for radius of curvature as small as 3.3mm.

  10. Advancement in organic nanofiber based transistors

    DEFF Research Database (Denmark)

    Jensen, Per Baunegaard With; Kjelstrup-Hansen, Jakob; Tavares, Luciana;

    The focus of this project is to study the light emission from nanofiber based organic light-emitting transistors (OLETs) with the overall aim of developing efficient, nanoscale light sources with different colors integrated on-chip. The research performed here regards the fabrication and characte......The focus of this project is to study the light emission from nanofiber based organic light-emitting transistors (OLETs) with the overall aim of developing efficient, nanoscale light sources with different colors integrated on-chip. The research performed here regards the fabrication and...

  11. Dielectric Engineered Tunnel Field-Effect Transistor

    OpenAIRE

    Ilatikhameneh, Hesameddin; Tarek A. Ameen; Klimeck, Gerhard; Appenzeller, Joerg; Rahman, Rajib

    2015-01-01

    The dielectric engineered tunnel field-effect transistor (DE-TFET) as a high performance steep transistor is proposed. In this device, a combination of high-k and low-k dielectrics results in a high electric field at the tunnel junction. As a result a record ON-current of about 1000 uA/um and a subthreshold swing (SS) below 20mV/dec are predicted for WTe2 DE-TFET. The proposed TFET works based on a homojunction channel and electrically doped contacts both of which are immune to interface stat...

  12. Static Characteristics of the Ferroelectric Transistor Inverter

    Science.gov (United States)

    Mitchell, Cody; Laws, crystal; MacLeond, Todd C.; Ho, Fat D.

    2010-01-01

    The inverter is one of the most fundamental building blocks of digital logic, and it can be used as the foundation for understanding more complex logic gates and circuits. This paper presents the characteristics of an inverter circuit using a ferroelectric field-effect transistor. The voltage transfer characteristics are analyzed with respect to varying parameters such as supply voltage, input voltage, and load resistance. The effects of the ferroelectric layer between the gate and semiconductor are examined, and comparisons are made between the inverters using ferroelectric transistors and those using traditional MOSFETs.

  13. Switching Characteristics of Ferroelectric Transistor Inverters

    Science.gov (United States)

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

    2010-01-01

    This paper presents the switching characteristics of an inverter circuit using a ferroelectric field effect transistor, FeFET. The propagation delay time characteristics, phl and plh are presented along with the output voltage rise and fall times, rise and fall. The propagation delay is the time-delay between the V50% transitions of the input and output voltages. The rise and fall times are the times required for the output voltages to transition between the voltage levels V10% and V90%. Comparisons are made between the MOSFET inverter and the ferroelectric transistor inverter.

  14. Electrical Compact Modeling of Graphene Base Transistors

    Directory of Open Access Journals (Sweden)

    Sébastien Frégonèse

    2015-11-01

    Full Text Available Following the recent development of the Graphene Base Transistor (GBT, a new electrical compact model for GBT devices is proposed. The transistor model includes the quantum capacitance model to obtain a self-consistent base potential. It also uses a versatile transfer current equation to be compatible with the different possible GBT configurations and it account for high injection conditions thanks to a transit time based charge model. Finally, the developed large signal model has been implemented in Verilog-A code and can be used for simulation in a standard circuit design environment such as Cadence or ADS. This model has been verified using advanced numerical simulation.

  15. Fundamentals of RF and microwave transistor amplifiers

    CERN Document Server

    Bahl, Inder J

    2009-01-01

    A Comprehensive and Up-to-Date Treatment of RF and Microwave Transistor Amplifiers This book provides state-of-the-art coverage of RF and microwave transistor amplifiers, including low-noise, narrowband, broadband, linear, high-power, high-efficiency, and high-voltage. Topics covered include modeling, analysis, design, packaging, and thermal and fabrication considerations. Through a unique integration of theory and practice, readers will learn to solve amplifier-related design problems ranging from matching networks to biasing and stability. More than 240 problems are included to help read

  16. TWO-LAYER CRYSTAL SQUARE FOR TRANSISTORS ON A SINGLE CHIP

    OpenAIRE

    Haissam El-Aawar

    2015-01-01

    The number of transistors on a chip plays the main role in increasing the speed and performance of a microprocessor; more transistors, more speed. Increasing the number of transistors will be limited due to the design complexity and density of transistors. This article aims to introduce a new approach to increasing the number of transistors on a chip. The basic idea is to construct two-layer crystal square for transistors; this allows to increase the number of transistors two addi...

  17. A High-Voltage Level Tolerant Transistor Circuit

    OpenAIRE

    Annema, Anne Johan; Geelen, Godefridus Johannes Gertrudis Maria

    2001-01-01

    A high-voltage level tolerant transistor circuit, comprising a plurality of cascoded transistors, including a first transistor (T1) operatively connected to a high-voltage level node (3) and a second transistor (T2) operatively connected to a low-voltage level node (2). The first transistor (T1) connects to a biasing circuit (8), such as a voltage level shifter, providing a variable biasing level (V1) relative to a voltage level (VH) at the high-voltage level node (3).

  18. High mobility and quantum well transistors design and TCAD simulation

    CERN Document Server

    Hellings, Geert

    2013-01-01

    For many decades, the semiconductor industry has miniaturized transistors, delivering increased computing power to consumers at decreased cost. However, mere transistor downsizing does no longer provide the same improvements. One interesting option to further improve transistor characteristics is to use high mobility materials such as germanium and III-V materials. However, transistors have to be redesigned in order to fully benefit from these alternative materials. High Mobility and Quantum Well Transistors: Design and TCAD Simulation investigates planar bulk Germanium pFET technology in chapters 2-4, focusing on both the fabrication of such a technology and on the process and electrical TCAD simulation. Furthermore, this book shows that Quantum Well based transistors can leverage the benefits of these alternative materials, since they confine the charge carriers to the high-mobility material using a heterostructure. The design and fabrication of one particular transistor structure - the SiGe Implant-Free Qu...

  19. Design method for a digitally trimmable MOS transistor structure

    DEFF Research Database (Denmark)

    Ning, Feng; Bruun, Erik

    1996-01-01

    A digitally trimmable MOS transistor is a MOS transistor consisting of a drain, a source, and a main gate as well as several subgates. The transconductance of the transistor is tunabledigitally by means of connecting subgates either to the main gate or to the source terminal. In this paper, a...... systematic design method for a digitally trimmable MOS transistor structure is proposed. Using the proposed method, we have designed a digitally trimmable MOS transistor structure and prototype devices were fabricated in a 2.4 micron n-well CMOS technology. Through measurements on these devices, the design...... method has been experimentally confirmed. The trimmable MOS transistor structure has been applied to a high precision current mirror to reduce mismatch in the current mirror. With the trimmable transistor structure, the mismatch can be reduced by more than one order of magnitude....

  20. Transistor-based particle detection systems and methods

    Science.gov (United States)

    Jain, Ankit; Nair, Pradeep R.; Alam, Muhammad Ashraful

    2015-06-09

    Transistor-based particle detection systems and methods may be configured to detect charged and non-charged particles. Such systems may include a supporting structure contacting a gate of a transistor and separating the gate from a dielectric of the transistor, and the transistor may have a near pull-in bias and a sub-threshold region bias to facilitate particle detection. The transistor may be configured to change current flow through the transistor in response to a change in stiffness of the gate caused by securing of a particle to the gate, and the transistor-based particle detection system may configured to detect the non-charged particle at least from the change in current flow.

  1. Characteristics of trap-filled gallium arsenide photoconductive switches used in high gain pulsed power applications

    International Nuclear Information System (INIS)

    The electrical properties of semi-insulating (SI) Gallium Arsenide (GaAs) have been investigated for some time, particularly for its application as a substrate in microelectronics. Of late this material has found a variety of applications other than as an isolation region between devices, or the substrate of an active device. High resistivity SI GaAs is increasingly being used in charged particle detectors and photoconductive semiconductor switches (PCSS). PCSS made from these materials operating in both the linear and non-linear modes have applications such as firing sets, as drivers for lasers, and in high impedance, low current Q-switches or Pockels cells. In the non-linear mode, it has also been used in a system to generate Ultra-Wideband (UWB) High Power Microwaves (HPM). The choice of GaAs over silicon offers the advantage that its material properties allow for fast, repetitive switching action. Furthermore photoconductive switches have advantages over conventional switches such as improved jitter, better impedance matching, compact size, and in some cases, lower laser energy requirement for switching action. The rise time of the PCSS is an important parameter that affects the maximum energy transferred to the load and it depends, in addition to other parameters, on the bias or the average field across the switch. High field operation has been an important goal in PCSS research. Due to surface flashover or premature material breakdown at higher voltages, most PCSS, especially those used in high power operation, need to operate well below the inherent breakdown voltage of the material. The lifetime or the total number of switching operations before breakdown, is another important switch parameter that needs to be considered for operation at high bias conditions. A lifetime of ∼ 104 shots has been reported for PCSS's used in UWB-HPM generation [5], while it has exceeded 108 shots for electro-optic drivers. Much effort is currently being channeled in the study

  2. Pixel x-ray detectors in epitaxial gallium arsenide with high-energy resolution capabilities (Fano factor experiment determination)

    International Nuclear Information System (INIS)

    Gallium Arsenide pixel detectors with an area of 170 x 320 microm2 and thickness of 5 microm, realized by molecular beam epitaxy, have been designed and tested with X- and γ rays. No significant charge trapping effects have been observed, and a charge collection efficiency of 100% has been measured. At room temperature an energy resolution of 671 eV full width at half maximum (FWHM) at 59.54 keV has been obtained, with an electronic noise of 532 eV FWHM. With the detector cooled to 243 K, the electronic noise is reduced to 373 eV FWHM, and the Kα and Kβ lines of the 55Fe spectrum can be resolved. The Fano factor for GaAs has been measured at room temperature with 59.5 keV photons yielding F = 0.12 ± 0.01

  3. Laser modulation of human immune system: inhibition of lymphocyte proliferation by a gallium-arsenide laser at low energy

    International Nuclear Information System (INIS)

    Cultured human lymphocytes were subjected to irradiation with a gallium-arsenide laser at energy fluence varying from 2.17 to 651 mJ/cm2, and the cell proliferation was assessed by [3H]thymidine incorporation. Both mitogenic proliferation in response to phytohemagglutinin and spontaneous cell proliferation were markedly inhibited by the laser irradiation at energy fluence as low as 10.85 mJ/cm2. Similarly, the functional response of cells to antigen stimulation in a one-way mixed-lymphocyte reaction was also diminished as a result of laser irradiation. The results indicate that laser irradiation at low energy can interfere with immune system in vitro, and similar modulation could potentially occur in human subjects exposed to laser irradiation in vivo

  4. Thermal transistor utilizing gas-liquid transition

    KAUST Repository

    Komatsu, Teruhisa S.

    2011-01-25

    We propose a simple thermal transistor, a device to control heat current. In order to effectively change the current, we utilize the gas-liquid transition of the heat-conducting medium (fluid) because the gas region can act as a good thermal insulator. The three terminals of the transistor are located at both ends and the center of the system, and are put into contact with distinct heat baths. The key idea is a special arrangement of the three terminals. The temperature at one end (the gate temperature) is used as an input signal to control the heat current between the center (source, hot) and another end (drain, cold). Simulating the nanoscale systems of this transistor, control of heat current is demonstrated. The heat current is effectively cut off when the gate temperature is cold and it flows normally when it is hot. By using an extended version of this transistor, we also simulate a primitive application for an inverter. © 2011 American Physical Society.

  5. Symmetry-Protected Quantum Adiabatic Transistors

    Science.gov (United States)

    Williamson, Dominic J.; Bartlett, Stephen D.

    2014-03-01

    An essential development in the history of computing was the invention of the transistor as it allowed logic circuits to be implemented in a robust and modular way. The physical characteristics of semiconductor materials were the key to building these devices. We aim to present an analogous development for quantum computing by showing that quantum adiabatic transistors (as defined by Flammia et al.) are built upon the essential qualities of symmetry-protected (SP) quantum ordered phases in one dimension. Flammia et al. and Renes et al. have demonstrated schemes for universal adiabatic quantum computation using quantum adiabatic transistors described by interacting spin chain models with specifically chosen Hamiltonian terms. We show that these models can be understood as specific examples of the generic situation in which all SP phases lead to quantum computation on encoded edge degrees of freedom by adiabatically traversing a symmetric phase transition into a trivial symmetric phase. This point of view is advantageous as it allows us to readily see that the computational properties of a quantum adiabatic transistor arise from a phase of matter rather than due to carefully tuned interactions.

  6. A ferroelectric transparent thin-film transistor

    NARCIS (Netherlands)

    Prins, MWJ; GrosseHolz, KO; Muller, G; Cillessen, JFM; Giesbers, JB; Weening, RP; Wolf, RM

    1996-01-01

    Operation is demonstrated of a field-effect transistor made of transparant oxidic thin films, showing an intrinsic memory function due to the usage of a ferroelectric insulator. The device consists of a high mobility Sb-doped n-type SnO2 semiconductor layer, PbZr0.2Ti0.8Os3 as a ferroelectric insula

  7. Organic field effect transistors containing bistable materials

    Czech Academy of Sciences Publication Activity Database

    Sworakowski, J.; Lutsyk, P.; Janus, K.; Kochalska, Anna; Nešpůrek, Stanislav

    Vilnius : Center for Physical Sciences and Technology, 2011. s. 35. ISBN 978-9955-634-36-2. [International Conference "Electronic and Related Properties of Organic Systems" /12./ - ERPOS-12. 11.07.2011-13.07.2011, Vilnius] EU Projects: European Commission(XE) 35859 - BIMORE Institutional research plan: CEZ:AV0Z40500505 Keywords : transistor * switch * bistability Subject RIV: CD - Macromolecular Chemistry

  8. Field-effect transistors based on phthalocyanines

    Czech Academy of Sciences Publication Activity Database

    Nešpůrek, Stanislav; Chaidogiannos, G.; Glezos, N.; Petraki, F.; Kennou, S.; Šebera, Jakub; Záliš, Stanislav; Kratochvílová, Irena; Sworakowski, J.

    Wroclaw : Oficyna Wydawnicza Politechniki Wroclawskiej, 2008. s. 24. ISBN 978-83-7493-399-5. [International Conference on Electrical and Related Properties of Organic Solids /11./. 13.07.2008-17.07.2008, Piechowice] R&D Projects: GA AV ČR KAN401770651 Institutional research plan: CEZ:AV0Z40500505 Keywords : transistor * phthalocyanine * molecular switch Subject RIV: CD - Macromolecular Chemistry

  9. Microwave Enhanced Cotunneling in SET Transistors

    DEFF Research Database (Denmark)

    Manscher, Martin; Savolainen, M.; Mygind, Jesper

    2003-01-01

    transistors has been measured as function of temperature, gate voltage, frequency, and applied microwave power. At low temperatures and applied power levels, including also sequential tunneling, the results can be made consistent with theory using the unknown damping in the microwave line as the only free...

  10. Resistance thermometers with MOS field effect transistors

    International Nuclear Information System (INIS)

    The temperature-dependent resistance change of n- as well as p-type MOS transistors has been investigated. Implantation of He ions increases the temperature sensitivity of the n-channel devices. The influence of magnetic fields up to 80 kG has been studied. (author)

  11. Studies on deep electronic levels in silicon and aluminium gallium arsenide alloys

    International Nuclear Information System (INIS)

    This thesis reports on investigations of the electrical and optical properties of deep impurity centers, related to the transition metals (TMs) Ti, Mo, W, V and Ni, in silicon. Emission rates, capture cross sections and photoionization cross sections for these impurities were determined by means of various Junction Space Charge Techniques (JSCTs), such as Deep Level Transient Spectroscopy (DLTS), dark capacitance transient and photo capacitance transient techniques. Changes in Gibbs free energy as a function of temperature were calculated for all levels. From this temperature dependence, the changes in enthalpy and entropy involved in the electron and hole transitions were deduced. The influence of high electric fields on the electronic levels in chalcogen-doped silicon were investigated using the dark capacitance transient technique. The enhancement of the electron emission from the deep centers indicated a more complex field enhancement model than the expected Poole-Frenkel effect for coulombic potentials. The possibility to determine charge states of defects using the Poole-Frenkel effect, as often suggested, is therefore questioned. The observation of a persistent decrease of the dark conductivity due to illumination in simplified AlGaAs/GaAs high Electron Mobility Transistors (HEMTs) over the temperature range 170K< T<300K is reported. A model for this peculiar behavior, based on the recombination of electrons in the two-dimensional electron gas (2DEG) located at the AlGaAs/GaAs interface with holes generated by a two-step excitation process via the deep EL2 center in the GaAs epilayer, is put forward

  12. Study of the structure of a thin aluminum layer on the vicinal surface of a gallium arsenide substrate by high-resolution electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Lovygin, M. V., E-mail: lemi@miee.ru; Borgardt, N. I. [National Research University of Electronic Technology “MIET” (Russian Federation); Seibt, M. [Universität Göttingen, IV Physikalisches Institut (Germany); Kazakov, I. P.; Tsikunov, A. V. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)

    2015-12-15

    The results of electron-microscopy studies of a thin epitaxial aluminum layer deposited onto a misoriented gallium-arsenide substrate are reported. It is established that the layer consists of differently oriented grains, whose crystal lattices are coherently conjugated with the substrate with the formation of misfit dislocations, as in the case of a layer on a singular substrate. Atomic steps on the substrate surface are visualized, and their influence on the growth of aluminum crystal grains is discussed.

  13. Observation of persistent photoconductivity in bulk Gallium Arsenide and Gallium Phosphide samples at cryogenic temperatures using the Whispering Gallery mode method

    CERN Document Server

    Hartnett, J G; Floch, J -M Le; Krupka, J; Tobar, M E; Cros, D

    2009-01-01

    Whispering Gallery modes in bulk cylindrical Gallium Arsenide and Gallium Phosphide samples have been examined both in darkness and under white light at cryogenics temperatures < 50 K. In both cases persistent photoconductivity was observed after initially exposing semiconductors to white light from a halogen lamp. Photoconductance decay time constants for GaP and GaAs were determined to be 0.900 +/- 0.081 ns and 1.098 +/- 0.063 ns, respectively, using this method.

  14. Recent progress in photoactive organic field-effect transistors

    Directory of Open Access Journals (Sweden)

    Yutaka Wakayama

    2014-04-01

    Full Text Available Recent progress in photoactive organic field-effect transistors (OFETs is reviewed. Photoactive OFETs are divided into light-emitting (LE and light-receiving (LR OFETs. In the first part, LE-OFETs are reviewed from the viewpoint of the evolution of device structures. Device performances have improved in the last decade with the evolution of device structures from single-layer unipolar to multi-layer ambipolar transistors. In the second part, various kinds of LR-OFETs are featured. These are categorized according to their functionalities: phototransistors, non-volatile optical memories, and photochromism-based transistors. For both, various device configurations are introduced: thin-film based transistors for practical applications, single-crystalline transistors to investigate fundamental physics, nanowires, multi-layers, and vertical transistors based on new concepts.

  15. Recent progress in photoactive organic field-effect transistors

    International Nuclear Information System (INIS)

    Recent progress in photoactive organic field-effect transistors (OFETs) is reviewed. Photoactive OFETs are divided into light-emitting (LE) and light-receiving (LR) OFETs. In the first part, LE-OFETs are reviewed from the viewpoint of the evolution of device structures. Device performances have improved in the last decade with the evolution of device structures from single-layer unipolar to multi-layer ambipolar transistors. In the second part, various kinds of LR-OFETs are featured. These are categorized according to their functionalities: phototransistors, non-volatile optical memories, and photochromism-based transistors. For both, various device configurations are introduced: thin-film based transistors for practical applications, single-crystalline transistors to investigate fundamental physics, nanowires, multi-layers, and vertical transistors based on new concepts. (review)

  16. Organic Field Effect Transistor Based Crosslinked Deoxyribonucleic Acid Gate Dielectric

    International Nuclear Information System (INIS)

    Deoxyribonucleic Acid (DNA) derived form marine waste products and modified with surfactant demonstrates excellent passive and active optical properties. In this study, we have fabricated organic field-effect transistors with DNA gate. In organic field effect transistors (OFETs) the gate dielectric plays a crucial role - these highly insulating thin film polymer layers are key-components in state of the art organic transistor devices. When replacing the polymer layer by introducing solution-processed thin film modified bio polymer (DNA) as gate insulator, transistor-characteristics are changed towards remanence-like hysteresis behaviours. The hysteresis-loops probed in bio-organic field effect transistors (BiOFETs) derived from DNA and fullerene derivatives form bistable states which can be used for memory devices at low operating voltage regime compared to similar organic thin film transistors using polymers as gate insulator

  17. Nanowire field effect transistors principles and applications

    CERN Document Server

    Jeong, Yoon-Ha

    2014-01-01

    “Nanowire Field Effect Transistor: Basic Principles and Applications” places an emphasis on the application aspects of nanowire field effect transistors (NWFET). Device physics and electronics are discussed in a compact manner, together with the p-n junction diode and MOSFET, the former as an essential element in NWFET and the latter as a general background of the FET. During this discussion, the photo-diode, solar cell, LED, LD, DRAM, flash EEPROM and sensors are highlighted to pave the way for similar applications of NWFET. Modeling is discussed in close analogy and comparison with MOSFETs. Contributors focus on processing, electrostatic discharge (ESD) and application of NWFET. This includes coverage of solar and memory cells, biological and chemical sensors, displays and atomic scale light emitting diodes. Appropriate for scientists and engineers interested in acquiring a working knowledge of NWFET as well as graduate students specializing in this subject.

  18. Cylindrical-shaped nanotube field effect transistor

    KAUST Repository

    Hussain, Muhammad Mustafa

    2015-12-29

    A cylindrical-shaped nanotube FET may be manufactured on silicon (Si) substrates as a ring etched into a gate stack and filled with semiconductor material. An inner gate electrode couples to a region of the gate stack inside the inner circumference of the ring. An outer gate electrode couples to a region of the gate stack outside the outer circumference of the ring. The multi-gate cylindrical-shaped nanotube FET operates in volume inversion for ring widths below 15 nanometers. The cylindrical-shaped nanotube FET demonstrates better short channel effect (SCE) mitigation and higher performance (I.sub.on/I.sub.off) than conventional transistor devices. The cylindrical-shaped nanotube FET may also be manufactured with higher yields and cheaper costs than conventional transistors.

  19. Application of the Johnson criteria to graphene transistors

    International Nuclear Information System (INIS)

    For 60 years, the Johnson criteria have guided the development of materials and the materials choices for field-effect and bipolar transistor technology. Intrinsic graphene is a semi-metal, precluding transistor applications, but only under lateral bias is a gap opened and transistor action possible. This first application of the Johnson criteria to biased graphene suggests that this material will struggle to ever achieve competitive commercial applications. (fast track communication)

  20. Low voltage and time constant organic synapse-transistor

    OpenAIRE

    Desbief, Simon; Kyndiah, Adrica; Guerin, David; Gentili, Denis; Murgia, Mauro; Lenfant, Stéphane; Alibart, Fabien; Cramer, Tobias; Biscarini, Fabio; Vuillaume, Dominique

    2015-01-01

    We report on an artificial synapse, an organic synapse-transistor (synapstor) working at 1 volt and with a typical response time in the range 100-200 ms. This device (also called NOMFET, Nanoparticle Organic Memory Field Effect Transistor) combines a memory and a transistor effect in a single device. We demonstrate that short-term plasticity (STP), a typical synaptic behavior, is observed when stimulating the device with input spikes of 1 volt. Both significant facilitating and depressing beh...

  1. Organic Thin-Film Transistor (OTFT-Based Sensors

    Directory of Open Access Journals (Sweden)

    Daniel Elkington

    2014-04-01

    Full Text Available Organic thin film transistors have been a popular research topic in recent decades and have found applications from flexible displays to disposable sensors. In this review, we present an overview of some notable articles reporting sensing applications for organic transistors with a focus on the most recent publications. In particular, we concentrate on three main types of organic transistor-based sensors: biosensors, pressure sensors and “e-nose”/vapour sensors.

  2. Electrical pulse burnout of transistors in intense ionizing radiation

    International Nuclear Information System (INIS)

    Tests examining possible synergistic effects of electrical pulses and ionizing radiation on transistors were performed and energy/power thresholds for transistor burnout determined. The effect of ionizing radiation on burnout thresholds was found to be minimal, indicating that electrical pulse testing in the absence of radiation produces burnout-threshold results which are applicable to IEMP studies. The conditions of ionized transistor junctions and radiation induced current surges at semiconductor device terminals are inherent in IEMP studies of electrical circuits

  3. Nonvolatile SRAM architecture using MOSFET-based spin-transistors

    OpenAIRE

    Shuto, Yusuke; Yamamoto, Shuu'ichirou; Sugahara, Satoshi

    2009-01-01

    The authors proposed and computationally analyzed nonvolatile static random access memory (NV-SRAM) architecture using metal-oxide-semiconductor field-effect transistor (MOSFET) type of spin-transistors referred to as pseudo-spin-MOSFET (PS-MOSFET). PS-MOSFET is a new circuit approach to reproduce the functions of spin-transistors, based on recently progressed magnetoresistive random access memory (MRAM) technology. The proposed NV-SRAM cell can be simply configured by connecting two PS-MOSFE...

  4. Hybrid light emitting transistors (Presentation Recording)

    Science.gov (United States)

    Muhieddine, Khalid; Ullah, Mujeeb; Namdas, Ebinazar B.; Burn, Paul L.

    2015-10-01

    Organic light-emitting diodes (OLEDs) are well studied and established in current display applications. Light-emitting transistors (LETs) have been developed to further simplify the necessary circuitry for these applications, combining the switching capabilities of a transistor with the light emitting capabilities of an OLED. Such devices have been studied using mono- and bilayer geometries and a variety of polymers [1], small organic molecules [2] and single crystals [3] within the active layers. Current devices can often suffer from low carrier mobilities and most operate in p-type mode due to a lack of suitable n-type organic charge carrier materials. Hybrid light-emitting transistors (HLETs) are a logical step to improve device performance by harnessing the charge carrier capabilities of inorganic semiconductors [4]. We present state of the art, all solution processed hybrid light-emitting transistors using a non-planar contact geometry [1, 5]. We will discuss HLETs comprised of an inorganic electron transport layer prepared from a sol-gel of zinc tin oxide and several organic emissive materials. The mobility of the devices is found between 1-5 cm2/Vs and they had on/off ratios of ~105. Combined with optical brightness and efficiencies of the order of 103 cd/m2 and 10-3-10-1 %, respectively, these devices are moving towards the performance required for application in displays. [1] M. Ullah, K. Tandy, S. D. Yambem, M. Aljada, P. L. Burn, P. Meredith, E. B. Namdas., Adv. Mater. 2013, 25, 53, 6213 [2] R. Capelli, S. Toffanin, G. Generali, H. Usta, A. Facchetti, M. Muccini, Nature Materials 2010, 9, 496 [3] T. Takenobu, S. Z. Bisri, T. Takahashi, M. Yahiro, C. Adachi, Y. Iwasa, Phys. Rev. Lett. 2008, 100, 066601 [4] H. Nakanotani, M. Yahiro, C. Adachi, K. Yano, Appl. Phys. Lett. 2007, 90, 262104 [5] K. Muhieddine, M. Ullah, B. N. Pal, P. Burn E. B. Namdas, Adv. Mater. 2014, 26,37, 6410

  5. Fully overheated single-electron transistor.

    Science.gov (United States)

    Laakso, M A; Heikkilä, T T; Nazarov, Yuli V

    2010-05-14

    We consider the fully overheated single-electron transistor, where the heat balance is determined entirely by electron transfers. We find three distinct transport regimes corresponding to cotunneling, single-electron tunneling, and a competition between the two. We find an anomalous sensitivity to temperature fluctuations at the crossover between the two latter regimes that manifests in an exceptionally large Fano factor of current noise. PMID:20866990

  6. Interfacial charge transfer in nanoscale polymer transistors

    OpenAIRE

    Worne, J. H.; Giridharagopal, R.; Kelly, K. F.; Natelson, D.

    2008-01-01

    Interfacial charge transfer plays an essential role in establishing the relative alignment of the metal Fermi level and the energy bands of organic semiconductors. While the details remain elusive in many systems, this charge transfer has been inferred in a number of photoemission experiments. We present electronic transport measurements in very short channel ($L < 100$ nm) transistors made from poly(3-hexylthiophene) (P3HT). As channel length is reduced, the evolution of the contact resistan...

  7. Theory of the Bloch Oscillating Transistor

    OpenAIRE

    Hassel, J.; Seppa, H.

    2004-01-01

    The Bloch oscillating transistor (BOT) is a device, where single electron current through a normal tunnel junction can be used to enhance Cooper pair current in a mesoscopic Josephson junction leading to signal amplification. In this paper we develop a theory, where the BOT dynamics is described as a two-level system. The theory is used to predict current-voltage characteristics and small-signal response. Transition from stable operation into hysteretic regime is studied. By identifying the t...

  8. Amorphous silicon for thin-film transistors

    OpenAIRE

    Schropp, Rudolf Emmanuel Isidore

    1987-01-01

    Hydrogenated amorphous silicon (a-Si:H) has considerable potential as a semiconducting material for large-area photoelectric and photovoltaic applications. Moreover, a-Si:H thin-film transistors (TFT’s) are very well suited as switching devices in addressable liquid crystal display panels and addressable image sensor arrays, due to a new technology of low-cost, Iow-temperature processing overlarge areas. ... Zie: Abstract

  9. Graphene-Dielectric Integration for Graphene Transistors

    OpenAIRE

    Liao, Lei; Duan, Xiangfeng

    2010-01-01

    Graphene is emerging as an interesting electronic material for future electronics due to its exceptionally high carrier mobility and single-atomic thickness. Graphene-dielectric integration is of critical importance for the development of graphene transistors and a new generation of graphene based electronics. Deposition of dielectric materials onto graphene is of significant challenge due to the intrinsic material incompatibility between pristine graphene and dielectric oxide materials. Here...

  10. Performance of a spin-based insulated gate field effect transistor

    OpenAIRE

    Hall, Kimberley C.; Flatté, Michael E.

    2006-01-01

    Fundamental physical properties limiting the performance of spin field effect transistors are compared to those of ordinary (charge-based) field effect transistors. Instead of raising and lowering a barrier to current flow these spin transistors use static spin-selective barriers and gate control of spin relaxation. The different origins of transistor action lead to distinct size dependences of the power dissipation in these transistors and permit sufficiently small spin-based transistors to ...

  11. A Heteroepitaxial Perovskite Metal-Base Transistor

    Energy Technology Data Exchange (ETDEWEB)

    Yajima, T.; Hikita, Y.; /Tokyo U.; Hwang, H.Y.; /Tokyo U. /JST, PRESTO /SLAC

    2011-08-11

    'More than Moore' captures a concept for overcoming limitations in silicon electronics by incorporating new functionalities in the constituent materials. Perovskite oxides are candidates because of their vast array of physical properties in a common structure. They also enable new electronic devices based on strongly-correlated electrons. The field effect transistor and its derivatives have been the principal oxide devices investigated thus far, but another option is available in a different geometry: if the current is perpendicular to the interface, the strong internal electric fields generated at back-to-back heterojunctions can be used for oxide electronics, analogous to bipolar transistors. Here we demonstrate a perovskite heteroepitaxial metal-base transistor operating at room temperature, enabled by interface dipole engineering. Analysis of many devices quantifies the evolution from hot-electron to permeable-base behaviour. This device provides a platform for incorporating the exotic ground states of perovskite oxides, as well as novel electronic phases at their interfaces.

  12. Organic transistors for electrophysiology (Presentation Recording)

    Science.gov (United States)

    Rivnay, Jonathan

    2015-10-01

    Efficient local transduction of biological signals is of critical importance for mapping brain activity and diagnosing pathological conditions. Traditional devices used to record electrophysiological signals are passive electrodes that require (pre)amplification with downstream electronics. Organic electrochemical transistors (OECTs) that utilize conducting polymer films as the channel have shown considerable promise as amplifying transducers due to their stability in aqueous conditions and high transconductance (>3 mS). The materials properties and physics of such transistors, however, remains largely unexplored thus limiting their potential. Here we show that the uptake of ionic charge from an electrolyte into a poly(3,4-ethylenedioxythiophene) doped with polystyrene sulfonate (PEDOT:PSS) OECT channel leads to a dependence of the effective capacitance on the entire volume of the film. Subsequently, device transconductance and time response vary with channel thickness, a defining characteristic that differentiates OECTs from field effect transistors, and provides a new degree of freedom for device engineering. Using this understanding we tailor OECTs for a variety of low (1-100 Hz) and high (1-10 kHz) frequency applications, including human electroencephalography, where high transconductance devices impart richer signal content without the need for additional amplification circuitry. We also show that the materials figure of merit OECTs is the product of hole mobility and volumetric capacitance of the channel, leading to design rules for novel high performance materials.

  13. Investigation of radiation stability of low-noise transistors

    International Nuclear Information System (INIS)

    The radiation effect on the noise characteristics of bipolar transistors (current, gain, base resistance and an equivalent noise charge) is studied. Several types of transistors of radiation resistance have been compared. Change in noise characteristics is shown to be caused mainly by dose dependence of a gain factor. The level of the absorbed dose, that determining the boundary of transistor KT399 application in fields of mixed radiation of accelerators has been determined experimentally. The level is 5x104 rad. For transistors KT3127, KT391 the dose level of 640 krad can be considered acceptable. 12 refs.; 3 figs

  14. A PWM transistor inverter for an ac electric vehicle drive

    Science.gov (United States)

    Slicker, J. M.

    1981-01-01

    A prototype system consisting of closely integrated motor, inverter, and transaxle has been built in order to demonstrate the feasibility of a three-phase ac transistorized inverter for electric vehicle applications. The microprocessor-controlled inverter employs monolithic power transistors to drive an oil-cooled, three-phase induction traction motor at a peak output power of 30 kW from a 144 V battery pack. Transistor safe switching requirements are discussed, and a circuit is presented for recovering trapped snubber inductor energy at transistor turn-off.

  15. A circuit model for defective bilayer graphene transistors

    Science.gov (United States)

    Umoh, Ime J.; Moktadir, Zakaria; Hang, Shuojin; Kazmierski, Tom J.; Mizuta, Hiroshi

    2016-05-01

    This paper investigates the behaviour of a defective single-gate bilayer graphene transistor. Point defects were introduced into pristine graphene crystal structure using a tightly focused helium ion beam. The transfer characteristics of the exposed transistors were measured ex-situ for different defect concentrations. The channel peak resistance increased with increasing defect concentration whilst the on-off ratio showed a decreasing trend for both electrons and holes. To understand the electrical behaviour of the transistors, a circuit model for bilayer graphene is developed which shows a very good agreement when validated against experimental data. The model allowed parameter extraction of bilayer transistor and can be implemented in circuit level simulators.

  16. Electron-induced damage to NPN transistors under different fluxes

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Radiation damage of NPN transistors under different fluxes with electron energy of 1.5 MeV was investigated in this article. It has been shown that when NPN transistors were irradiated to a given fluence at different electron fluxes, the shift of base current was dependent on flux. With electron flux decreasing, the shift of base current becomes larger, while collector current almost keeps constant. Thus, more degradation of NPN transistors could be caused by low-electron-flux irradiation, similar to enhanced low-dose-rate sensitivity (ELDRS) of transistors under 60Co γ-irradiation. Finally, the underlying mechanisms were discussed here.

  17. Design method for a digitally trimmable MOS transistor structure

    DEFF Research Database (Denmark)

    Ning, Feng; Bruun, Erik

    1996-01-01

    systematic design method for a digitally trimmable MOS transistor structure is proposed. Using the proposed method, we have designed a digitally trimmable MOS transistor structure and prototype devices were fabricated in a 2.4 micron n-well CMOS technology. Through measurements on these devices, the design...... method has been experimentally confirmed. The trimmable MOS transistor structure has been applied to a high precision current mirror to reduce mismatch in the current mirror. With the trimmable transistor structure, the mismatch can be reduced by more than one order of magnitude....

  18. Point defects and electric compensation in gallium arsenide single crystals; Punktdefekte und elektrische Kompensation in Galliumarsenid-Einkristallen

    Energy Technology Data Exchange (ETDEWEB)

    Kretzer, Ulrich

    2007-12-10

    In the present thesis the point-defect budget of gallium arsenide single crystals with different dopings is studied. It is shown, in which way the concentration of the single point defects depende on the concentration of the dopants, the stoichiometry deviation, and the position of the Fermi level. For this serve the results of the measurement-technical characterization of a large number of samples, in the fabrication of which these parameters were directedly varied. The main topic of this thesis lies in the development of models, which allow a quantitative description of the experimentally studied electrical and optical properties of gallium arsenide single crystals starting from the point-defect concentrations. Because from point defects charge carriers can be set free, their concentration determines essentially the charge-carrier concentration in the bands. In the ionized state point defects act as scattering centers for free charge carriers and influence by this the drift mobility of the charge carriers. A thermodynamic modeling of the point-defect formation yields statements on the equilibrium concentrations of the point defects in dependence on dopant concentration and stoichiometry deviation. It is show that the electrical properties of the crystals observed at room temperature result from the kinetic suppression of processes, via which the adjustment of a thermodynamic equilibrium between the point defects is mediated. [German] In der vorliegenden Arbeit wird der Punktdefekthaushalt von Galliumarsenid-Einkristallen mit unterschiedlichen Dotierungen untersucht. Es wird gezeigt, in welcher Weise die Konzentration der einzelnen Punktdefekte von der Konzentration der Dotierstoffe, der Stoechiometrieabweichung und der Lage des Ferminiveaus abhaengen. Dazu dienen die Ergebnisse der messtechnischen Charakterisierung einer grossen Anzahl von Proben, bei deren Herstellung diese Parameter gezielt variiert wurden. Der Schwerpunkt der Arbeit liegt in der Entwicklung

  19. Integration of GaInP/GaAs heterojunction bipolar transistors and high electron mobility transistors

    OpenAIRE

    Yang, YF; Hsu, CC; Yang, ES

    1996-01-01

    Integration of carbon-doped GaInP/GaAs heterojunction bipolar transistors (HBT's) and high electron mobility transistors (HEMT's) is demonstrated by growing an HBT on the top of a HEMT. A current gain of 60. a cutoff frequency of 59 GHz and a maximum oscillation frequency of 68 GHz were obtained for a 5 × 15 μm 2 self-aligned HBT. The HEMT with a gate length of 1.5 μm has a transconductance of 210 mS/mm, a cutoff frequency of 9 GHz and a maximum oscillation frequency of 22 GHz. It is shown th...

  20. Structural anomalies in undoped gallium arsenide observed in high-resolution diffraction imaging with monochromatic synchrotron radiation

    Science.gov (United States)

    Steiner, B.; Kuriyama, M.; Dobbyn, R. C.; Laor, U.; Larson, D.

    1989-01-01

    Novel, streak-like disruption features restricted to the plane of diffraction have recently been observed in images obtained by synchrotron radiation diffraction from undoped, semi-insulating gallium arsenide crystals. These features were identified as ensembles of very thin platelets or interfaces lying in (110) planes, and a structural model consisting of antiphase domain boundaries was proposed. We report here the other principal features observed in high resolution monochromatic synchrotron radiation diffraction images: (quasi) cellular structure; linear, very low-angle subgrain boundaries in (110) directions, and surface stripes in a (110) direction. In addition, we report systematic differences in the acceptance angle for images involving various diffraction vectors. When these observations are considered together, a unifying picture emerges. The presence of ensembles of thin (110) antiphase platelet regions or boundaries is generally consistent not only with the streak-like diffraction features but with the other features reported here as well. For the formation of such regions we propose two mechanisms, operating in parallel, that appear to be consistent with the various defect features observed by a variety of techniques.

  1. Non-local exchange correlation functionals impact on the structural, electronic and optical properties of III-V arsenides

    KAUST Repository

    Anua, N. Najwa

    2013-08-20

    Exchange correlation (XC) energy functionals play a vital role in the efficiency of density functional theory (DFT) calculations, more soundly in the calculation of fundamental electronic energy bandgap. In the present DFT study of III-arsenides, we investigate the implications of XC-energy functional and corresponding potential on the structural, electronic and optical properties of XAs (X = B, Al, Ga, In). Firstly we report and discuss the optimized structural lattice parameters and the band gap calculations performed within different non-local XC functionals as implemented in the DFT-packages: WIEN2k, CASTEP and SIESTA. These packages are representative of the available code in ab initio studies. We employed the LDA, GGA-PBE, GGA-WC and mBJ-LDA using WIEN2k. In CASTEP, we employed the hybrid functional, sX-LDA. Furthermore LDA, GGA-PBE and meta-GGA were employed using SIESTA code. Our results point to GGA-WC as a more appropriate approximation for the calculations of structural parameters. However our electronic bandstructure calculations at the level of mBJ-LDA potential show considerable improvements over the other XC functionals, even the sX-LDA hybrid functional. We report also the optical properties within mBJ potential, which show a nice agreement with the experimental measurements in addition to other theoretical results. © 2013 IOP Publishing Ltd.

  2. High-performance organic/inorganic hybrid heterojunction based on Gallium Arsenide (GaAs) substrates and a conjugated polymer

    Science.gov (United States)

    Jameel, D. A.; Felix, J. F.; Aziz, M.; Al Saqri, N.; Taylor, D.; de Azevedo, W. M.; da Silva, E. F.; Albalawi, H.; Alghamdi, H.; Al Mashary, F.; Henini, M.

    2015-12-01

    In this paper, we present an extensive study of the electrical properties of organic-inorganic hybrid heterojunctions. Polyaniline (PANI) thin films were deposited by a very simple technique on (1 0 0) and (3 1 1)B n-type Gallium Arsenide (GaAs) substrates to fabricate hybrid devices with excellent electrical properties. The hybrid devices were electrically characterized using current-voltage (I-V), capacitance-voltage (C-V) and deep level transient spectroscopy (DLTS) measurements in the temperature range 20-440 K. The analysis of I-V characteristics based on the thermionic emission mechanism has shown a decrease of the barrier height and an increase of the ideality factor at lower temperatures for both hybrid devices. The interface states were analyzed by series resistance obtained using the C-G-V methods. The interface state density (Dit) of PANI/(1 0 0) GaAs devices is approximately one order of magnitude higher than that of PANI/(3 1 1)B GaAs devices. This behaviour is attributed to the effect of crystallographic orientation of the substrates, and was confirmed by DLTS results as well. Additionally, the devices show excellent air stability, with rectification ratio values almost unaltered after two years of storage under ambient conditions, making the polyaniline an interesting conductor polymer for future devices applications.

  3. CO2 laser-based dispersion interferometer utilizing orientation-patterned gallium arsenide for plasma density measurements

    International Nuclear Information System (INIS)

    A dispersion interferometer based on the second-harmonic generation of a carbon dioxide laser in orientation-patterned gallium arsenide has been developed for measuring electron density in plasmas. The interferometer includes two nonlinear optical crystals placed on opposite sides of the plasma. This instrument has been used to measure electron line densities in a pulsed radio-frequency generated argon plasma. A simple phase-extraction technique based on combining measurements from two successive pulses of the plasma has been used. The noise-equivalent line density was measured to be 1.7 × 1017 m−2 in a detection bandwidth of 950 kHz. One of the orientation-patterned crystals produced 13 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 13 W of peak power. Two crystals arranged sequentially produced 58 mW of peak power at the second-harmonic wavelength from a carbon dioxide laser with 37 W of peak power

  4. Emergence of spin-orbit fields in magnetotransport of quasi-two-dimensional iron on gallium arsenide

    Science.gov (United States)

    Hupfauer, T.; Matos-Abiague, A.; Gmitra, M.; Schiller, F.; Loher, J.; Bougeard, D.; Back, C. H.; Fabian, J.; Weiss, D.

    2015-06-01

    The desire for higher information capacities drives the components of electronic devices to ever smaller dimensions so that device properties are determined increasingly more by interfaces than by the bulk structure of the constituent materials. Spintronic devices, especially, benefit from the presence of interfaces--the reduced structural symmetry creates emergent spin-orbit fields that offer novel possibilities to control device functionalities. But where does the bulk end, and the interface begin? Here we trace the interface-to-bulk transition, and follow the emergence of the interfacial spin-orbit fields, in the conducting states of a few monolayers of iron on top of gallium arsenide. We observe the transition from the interface- to bulk-induced lateral crystalline magnetoanisotropy, each having a characteristic symmetry pattern, as the epitaxially grown iron channel increases from four to eight monolayers. Setting the upper limit on the width of the interface-imprinted conducting channel is an important step towards an active control of interfacial spin-orbit fields.

  5. Group IV nanotube transistors for next generation ubiquitous computing

    Science.gov (United States)

    Fahad, Hossain M.; Hussain, Aftab M.; Sevilla Torres, Galo A.; Banerjee, Sanjay K.; Hussain, Muhammad M.

    2014-06-01

    Evolution in transistor technology from increasingly large power consuming single gate planar devices to energy efficient multiple gate non-planar ultra-narrow (internet of things, the NTFET offers a new transistor topology alternative with maximum benefits from performance-energy efficiency-functionality perspective.

  6. The Complete Semiconductor Transistor and Its Incomplete Forms

    Institute of Scientific and Technical Information of China (English)

    Jie Binbin; Sah Chih-Tang

    2009-01-01

    This paper describes the definition of the complete transistor. For semiconductor devices, the complete transistor is always bipolar, namely, its electrical characteristics contain both electron and hole currents controlled by their spatial charge distributions. Partially complete or incomplete transistors, via coined names or/and designed physical geometries, included the 1949 Shockley p/n junction transistor (later called Bipolar Junction Transistor,BJT), the 1952 Shockley unipolar 'field-effect' transistor (FET, later called the p/n Junction Gate FET or JGFET), as well as the field-effect transistors introduced by later investigators. Similarities between the surface-channel MOS-gate FET (MOSFET) and the volume-channel BJT are illustrated. The bipolar currents, identified by us in a recent nanometer FET with 2-MOS-gates on thin and nearly pure silicon base, led us to the recognition of the physical makeup and electrical current and charge compositions of a complete transistor and its extension to other three or more terminal signal processing devices, and also the importance of the terminal contacts.

  7. The Smallest Transistor-Based Nonautonomous Chaotic Circuit

    DEFF Research Database (Denmark)

    Lindberg, Erik; Murali, K.; Tamasevicius, Arunas

    2005-01-01

    A nonautonomous chaotic circuit based on one transistor, two capacitors, and two resistors is described. The mechanism behind the chaotic performance is based on “disturbance of integration.” The forward part and the reverse part of the bipolar transistor are “fighting” about the charging of a...

  8. On the 50th Anniversary of the Transistor

    DEFF Research Database (Denmark)

    Stassen, Flemming

    1997-01-01

    This paper celebrates the 50th anniversary of the invention of the bipolar transistor in 1947. Combined with the inventions of integration and planar technology, the invention of the transistor marks the beginning of a period of unprecedented growth, the industrialization of electronics....

  9. Fabrication and characterization of advanced Organic Thin Film Transistors

    OpenAIRE

    Scaldaferri, Rossana

    2009-01-01

    The thesis aims to the development of Organic Thin Film Transistors and more complex devices based on organic materials. The experimental work demonstrates the possibility to manufacture transistors and more complex circuits with innovative polymers and technologies, leading to an experimental validation of the possibility to realize all-organic devices.

  10. Method for double-sided processing of thin film transistors

    Science.gov (United States)

    Yuan, Hao-Chih; Wang, Guogong; Eriksson, Mark A.; Evans, Paul G.; Lagally, Max G.; Ma, Zhenqiang

    2008-04-08

    This invention provides methods for fabricating thin film electronic devices with both front- and backside processing capabilities. Using these methods, high temperature processing steps may be carried out during both frontside and backside processing. The methods are well-suited for fabricating back-gate and double-gate field effect transistors, double-sided bipolar transistors and 3D integrated circuits.

  11. The Ebers-Moll model for magnetic bipolar transistors

    OpenAIRE

    Fabian, J.; Zutic, I.

    2004-01-01

    The equivalent electrical circuit of the Ebers-Moll type is introduced for magnetic bipolar transistors. In addition to conventional diodes and current sources, the new circuit comprises two novel elements due to spin-charge coupling. A classification scheme of the operating modes of magnetic bipolar transistors in the low bias regime is presented.

  12. Single-event burnout of epitaxial bipolar transistors

    Energy Technology Data Exchange (ETDEWEB)

    Kuboyama, Satoshi; Sugimoto, Kenji; Matsuda, Sumio [National Space Development Agency of Japan, Ysukuba, Ibaraki (Japan); Hirao, Toshio

    1998-10-01

    Single-event burnout (SEB) of bipolar junction transistors (BJTs) has been observed nondestructively. It was revealed that all the NPN BJTs including small signal transistors with thinner epitaxial layer were inherently susceptible to the SEB phenomenon. It was demonstrated that several design parameters of BJTs were responsible for SEB susceptibility. Additionally, destructive and nondestructive modes of SEB were identified. (author)

  13. Single-event burnout of epitaxial bipolar transistors

    Energy Technology Data Exchange (ETDEWEB)

    Kuboyama, S.; Sugimoto, K.; Shugyo, S.; Matsuda, S. [National Space Development Agency of Japan, Tsukuba, Ibaraki (Japan); Hirao, T. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan)

    1998-12-01

    Single-Event Burnout (SEB) of bipolar junction transistors (BJTs) has been observed nondestructively. It was revealed that all the NPN BJTs, including small signal transistors, with thinner epitaxial layers were inherently susceptible to the SEB phenomenon. It was demonstrated that several design parameters of BJTs were responsible for SEB susceptibility. Additionally, destructive and nondestructive modes of SEB were identified.

  14. Flexible Proton-Gated Oxide Synaptic Transistors on Si Membrane.

    Science.gov (United States)

    Zhu, Li Qiang; Wan, Chang Jin; Gao, Ping Qi; Liu, Yang Hui; Xiao, Hui; Ye, Ji Chun; Wan, Qing

    2016-08-24

    Ion-conducting materials have received considerable attention for their applications in fuel cells, electrochemical devices, and sensors. Here, flexible indium zinc oxide (InZnO) synaptic transistors with multiple presynaptic inputs gated by proton-conducting phosphorosilicate glass-based electrolyte films are fabricated on ultrathin Si membranes. Transient characteristics of the proton gated InZnO synaptic transistors are investigated, indicating stable proton-gating behaviors. Short-term synaptic plasticities are mimicked on the proposed proton-gated synaptic transistors. Furthermore, synaptic integration regulations are mimicked on the proposed synaptic transistor networks. Spiking logic modulations are realized based on the transition between superlinear and sublinear synaptic integration. The multigates coupled flexible proton-gated oxide synaptic transistors may be interesting for neuroinspired platforms with sophisticated spatiotemporal information processing. PMID:27471861

  15. Simulation of a spintronic transistor: A study of its performance

    International Nuclear Information System (INIS)

    We study theoretically the magnetic bipolar transistor, and compare its performance with common bipolar transistor. We present not only the simulation results for the characteristic curves, but also other relevant parameters related with its performance, such as: the current amplification factor, the open-loop gain, the hybrid parameters and the cutoff frequency. We noted that the spin-charge coupling introduces new phenomena that enrich the functionality characteristics of the magnetic bipolar transistor. Among other things, it has an adjustable band structure, which may be modified during the device operation; it exhibits the already known spin-voltaic effect. On the other hand, we observed that it is necessary a large g-factor to analyze the influence of the field B over the transistor. Nevertheless, we consider the magnetic bipolar transistor as a promising device for spintronic applications

  16. Hysteresis modeling in graphene field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Winters, M.; Rorsman, N. [Department of Microtechnology and Nanoscience, Chalmers University of Technology, 412-96 Göteborg (Sweden); Sveinbjörnsson, E. Ö. [Science Institute, University of Iceland, IS-107 Reykjavik (Iceland)

    2015-02-21

    Graphene field effect transistors with an Al{sub 2}O{sub 3} gate dielectric are fabricated on H-intercalated bilayer graphene grown on semi-insulating 4H-SiC by chemical vapour deposition. DC measurements of the gate voltage v{sub g} versus the drain current i{sub d} reveal a severe hysteresis of clockwise orientation. A capacitive model is used to derive the relationship between the applied gate voltage and the Fermi energy. The electron transport equations are then used to calculate the drain current for a given applied gate voltage. The hysteresis in measured data is then modeled via a modified Preisach kernel.

  17. Drain Voltage Scaling in Carbon Nanotube Transistors

    OpenAIRE

    Radosavljevic, M.; Heinze, S.; Tersoff, J.; Avouris, Ph.

    2003-01-01

    While decreasing the oxide thickness in carbon nanotube field-effect transistors (CNFETs) improves the turn-on behavior, we demonstrate that this also requires scaling the range of the drain voltage. This scaling is needed to avoid an exponential increase in Off-current with drain voltage, due to modulation of the Schottky barriers at both the source and drain contact. We illustrate this with results for bottom-gated ambipolar CNFETs with oxides of 2 and 5 nm, and give an explicit scaling rul...

  18. Gate engineered performance of single molecular transistor

    Science.gov (United States)

    Ray, S. J.

    2016-05-01

    The operation, performance and electrostatics of multigated Single Molecular Transistor (SMT) devices are investigated using first-principles based density functional theory calculations for planar (pentacene) and non-planar (sucrose) molecules as islands. It has been found that the incorporation of larger numbers of gates allows enhanced electrostatic control in the SMT operation which has been quantified from the energy calculations and estimation of the gate capacitances. The effect of multiple gates is more dominant for a non-planar molecule than a planar molecule within an SMT which indicates the usefulness of such multi-gate architectures for future nanoelectronic devices.

  19. Dose Rate Effects in Linear Bipolar Transistors

    Science.gov (United States)

    Johnston, Allan; Swimm, Randall; Harris, R. D.; Thorbourn, Dennis

    2011-01-01

    Dose rate effects are examined in linear bipolar transistors at high and low dose rates. At high dose rates, approximately 50% of the damage anneals at room temperature, even though these devices exhibit enhanced damage at low dose rate. The unexpected recovery of a significant fraction of the damage after tests at high dose rate requires changes in existing test standards. Tests at low temperature with a one-second radiation pulse width show that damage continues to increase for more than 3000 seconds afterward, consistent with predictions of the CTRW model for oxides with a thickness of 700 nm.

  20. Coherent Matterwave Emission from an Atomtronic Transistor

    Science.gov (United States)

    Straatsma, Cameron; Anderson, Dana

    2016-05-01

    We investigate matterwave emission from a triple-well ``transistor'' atomic potential consisting of a ``source'' well treated as a reservoir having fixed chemical potential and temperature, a narrow ``gate'' well, and a ``drain'' well coupled to the vacuum. The ground state of the gate well is occupied by a Bose-Einstein condensate having large chemical potential along with the first excited state of the potential. These lower states are coupled to the two highest lying bound states lying near the top of the barriers separating the gate from the other two wells. We show that the energy level separations of the two lower states and the two upper states can be made degenerate by design of the Gaussian barrier widths and separation. When degenerate, the two pairs of states are strongly coupled by phonon exchange. We seek a self-consistent solution for the coupling between the high-lying states and the ground state pair, which occurs due to stimulated absorption and emission of phonons. In steady-state, coupling of the upper states leads to matter wave emission such that the emission of the two states is mutually coherent. The output from the transistor is thus an intensity-modulated matterwave whose frequency is approximately equal to the ground-state trap frequency.

  1. Carbon nanotubes field effect transistors biosensors

    Directory of Open Access Journals (Sweden)

    M.P. Marco

    2012-03-01

    Full Text Available Carbon nanotube transistor arrays (CNTFETs wereused as biosensors to detect DNA hybridization andto recognize two anabolic steroids, stanozolol (Stzand methylboldenone (MB. Single strand DNA andantibodies specific for STz and MB were immobilizedon the carbon nanotubes (CNTs in situ in the deviceusing two different approaches: direct noncovalentbonding of antibodies to the devices and covalentlytrough a polymer previously attached to theCNTFETs. A new approach to ensure specificadsorption of the biomolecules to the nanotubeswas developed. The polymer poly(methylmethacrylate0.8-co-poly (ethyleneglycolmethacrylate0.8-co-N-succinimidyl methacrylate0.1was synthesized and bonded noncovalently to thenanotube. Aminated single-strand DNA or antibodiesspecific for Stz and MB were then attached covalentlyto the polymer. Statistically significant changes wereobserved in key transistor parameters for both DNAhybridization and steroids recognition. Regardingthe detection mechanism, in addition to chargetransfer, Schottky barrier, SB, modification, andscattering potential reported by other authors, anelectron/hole trapping mechanism leading tohysteresis modification has been determined. Thepresence of polymer seems to hinder the modulationof the electrode-CNT contact.

  2. Light-trapping and recycling for extraordinary power conversion in ultra-thin gallium-arsenide solar cells.

    Science.gov (United States)

    Eyderman, Sergey; John, Sajeev

    2016-01-01

    We demonstrate nearly 30% power conversion efficiency in ultra-thin (~200 nm) gallium arsenide photonic crystal solar cells by numerical solution of the coupled electromagnetic Maxwell and semiconductor drift-diffusion equations. Our architecture enables wave-interference-induced solar light trapping in the wavelength range from 300-865 nm, leading to absorption of almost 90% of incoming sunlight. Our optimized design for 200 nm equivalent bulk thickness of GaAs, is a square-lattice, slanted conical-pore photonic crystal (lattice constant 550 nm, pore diameter 600 nm, and pore depth 290 nm), passivated with AlGaAs, deposited on a silver back-reflector, with ITO upper contact and encapsulated with SiO2. Our model includes both radiative and non-radiative recombination of photo-generated charge carriers. When all light from radiative recombination is assumed to escape the structure, a maximum achievable photocurrent density (MAPD) of 27.6 mA/cm(2) is obtained from normally incident AM 1.5 sunlight. For a surface non-radiative recombination velocity of 10(3) cm/s, this corresponds to a solar power conversion efficiency of 28.3%. When all light from radiative recombination is trapped and reabsorbed (complete photon recycling) the power conversion efficiency increases to 29%. If the surface recombination velocity is reduced to 10 cm/sec, photon recycling is much more effective and the power conversion efficiency reaches 30.6%. PMID:27334045

  3. Light-trapping and recycling for extraordinary power conversion in ultra-thin gallium-arsenide solar cells

    Science.gov (United States)

    Eyderman, Sergey; John, Sajeev

    2016-01-01

    We demonstrate nearly 30% power conversion efficiency in ultra-thin (~200 nm) gallium arsenide photonic crystal solar cells by numerical solution of the coupled electromagnetic Maxwell and semiconductor drift-diffusion equations. Our architecture enables wave-interference-induced solar light trapping in the wavelength range from 300–865 nm, leading to absorption of almost 90% of incoming sunlight. Our optimized design for 200 nm equivalent bulk thickness of GaAs, is a square-lattice, slanted conical-pore photonic crystal (lattice constant 550 nm, pore diameter 600 nm, and pore depth 290 nm), passivated with AlGaAs, deposited on a silver back-reflector, with ITO upper contact and encapsulated with SiO2. Our model includes both radiative and non-radiative recombination of photo-generated charge carriers. When all light from radiative recombination is assumed to escape the structure, a maximum achievable photocurrent density (MAPD) of 27.6 mA/cm2 is obtained from normally incident AM 1.5 sunlight. For a surface non-radiative recombination velocity of 103 cm/s, this corresponds to a solar power conversion efficiency of 28.3%. When all light from radiative recombination is trapped and reabsorbed (complete photon recycling) the power conversion efficiency increases to 29%. If the surface recombination velocity is reduced to 10 cm/sec, photon recycling is much more effective and the power conversion efficiency reaches 30.6%. PMID:27334045

  4. Simulation of the single event transients in a two transistor clusters CMOS 28-nm DICE cell

    International Nuclear Information System (INIS)

    Single event upsets of CMOS DICE cells depend on the cell layout. A new specific DICE cell layout design is based on two spaced transistor clusters of the DICE cell each consisting of the four transistors-one closed pair N-PMOS transistors and one opened pair N-PMOS transistors. The result of a single nuclear particle strike only on the one transistor cluster of the DICE cell is the single event transient but not the single-event upset

  5. Organic semiconductors for organic field-effect transistors

    Directory of Open Access Journals (Sweden)

    Yoshiro Yamashita

    2009-01-01

    Full Text Available The advantages of organic field-effect transistors (OFETs, such as low cost, flexibility and large-area fabrication, have recently attracted much attention due to their electronic applications. Practical transistors require high mobility, large on/off ratio, low threshold voltage and high stability. Development of new organic semiconductors is key to achieving these parameters. Recently, organic semiconductors have been synthesized showing comparable mobilities to amorphous-silicon-based FETs. These materials make OFETs more attractive and their applications have been attempted. New organic semiconductors resulting in high-performance FET devices are described here and the relationship between transistor characteristics and chemical structure is discussed.

  6. GaN transistors for efficient power conversion

    CERN Document Server

    Lidow, Alex; de Rooij, Michael; Reusch, David

    2014-01-01

    The first edition of GaN Transistors for Efficient Power Conversion was self-published by EPC in 2012, and is currently the only other book to discuss GaN transistor technology and specific applications for the technology. More than 1,200 copies of the first edition have been sold through Amazon or distributed to selected university professors, students and potential customers, and a simplified Chinese translation is also available. The second edition has expanded emphasis on applications for GaN transistors and design considerations. This textbook provides technical and application-focused i

  7. Multi-gate synergic modulation in laterally coupled synaptic transistors

    Science.gov (United States)

    Zhu, Li Qiang; Xiao, Hui; Liu, Yang Hui; Wan, Chang Jin; Shi, Yi; Wan, Qing

    2015-10-01

    Laterally coupled oxide-based synaptic transistors with multiple gates are fabricated on phosphorosilicate glass electrolyte films. Electrical performance of the transistor can be evidently improved when the device is operated in a tri-gate synergic modulation mode. Excitatory post-synaptic current and paired pulse facilitation (PPF) behavior of biological synapses are mimicked, and PPF index can be effectively tuned by the voltage applied on the modulatory terminal. At last, superlinear to sublinear synaptic integration regulation is also mimicked by applying a modulatory pulse on the third modulatory terminal. The multi-gate oxide-based synaptic transistors may find potential applications in biochemical sensors and neuromorphic systems.

  8. Large magnetocurrents in double-barrier tunneling transistors

    International Nuclear Information System (INIS)

    Magnetic tunneling transistors (MTT) with double tunneling barriers are fabricated. The structure of the transistor is AFM/FM/I/FM/I/FM/AFM, and ferromagnetic layers serve as the emitter, base and collector. This double-barrier tunneling transistor (DBTT) has an advantage of controlling the potential between the base and collector, compared to the Schottky-barrier-based base and collector of MTT. We found that the collector current density of DBTT is at least 103 times larger than that of conventional MTT, since tunneling through AlOx barrier provides much larger current density than that through Schottky barrier

  9. Direct coupled amplifiers using field effect transistors

    International Nuclear Information System (INIS)

    The concept of the uni-polar field effect transistor (P.E.T.) was known before the invention of the bi-polar transistor but it is only recently that they have been made commercially. Being produced as yet only in small quantities, their price imposes a restriction on use to circuits where their peculiar properties can be exploited to the full. One such application is described here where the combination of low voltage drift and relatively low input leakage current are necessarily used together. One of the instruments used to control nuclear reactors has a logarithmic response to the mean output current from a polarised ionisation chamber. The logarithmic signal is then differentiated electrically, the result being displayed on a meter calibrated to show the reactor divergence or doubling time. If displayed in doubling time the scale is calibrated reciprocally. Because of the wide range obtained in the logarithmic section and the limited supply voltage, an output of 1 volt per decade change in ionisation current is used. Differentiating this gives a current of 1.5 x 10-8 A for p.s.D. (20 sec. doubling time) in the differentiating amplifier. To overcome some of the problems of noise due to statistical variations in input current, the circuit design necessitates a resistive path to ground at the amplifier input of 20 M.ohms. A schematic diagram is shown. 1. It is evident that a zero drift of 1% can be caused by a leakage current of 1.5 x 10-10 A or an offset voltage of 3 mV at the amplifier input. Although the presently used electrometer valve is satisfactory from the point of view of grid current, there have been sudden changes in grid to grid voltage (the valve is a double triode) of up to 10 m.V. It has been found that a pair of F.E.T's. can be used to replace the electrometer valve so long as care is taken in correct balance of the two devices. An investigation has been made into the characteristics of some fourteen devices to see whether those with very different

  10. Individual SWCNT based ionic field effect transistor

    Science.gov (United States)

    Pang, Pei; He, Jin; Park, Jae Hyun; Krstic, Predrag; Lindsay, Stuart

    2011-03-01

    Here we report that the ionic current through a single-walled carbon nanotube (SWCNT) can be effectively gated by a perpendicular electrical field from a top gate electrode, working as ionic field effect transistor. Both our experiment and simulation confirms that the electroosmotic current (EOF) is the main component in the ionic current through the SWCNT and is responsible for the gating effect. We also studied the gating efficiency as a function of solution concentration and pH and demonstrated that the device can work effectively in the physiological relevant condition. This work opens the door to use CNT based nanofluidics for ion and molecule manipulation. This work was supported by the DNA Sequencing Technology Program of the National Human Genome Research Institute (1RC2HG005625-01, 1R21HG004770-01), Arizona Technology Enterprises and the Biodesign Institute.

  11. Antiferromagnetic Spin Wave Field-Effect Transistor

    Science.gov (United States)

    Cheng, Ran; Daniels, Matthew W.; Zhu, Jian-Gang; Xiao, Di

    2016-04-01

    In a collinear antiferromagnet with easy-axis anisotropy, symmetry dictates that the spin wave modes must be doubly degenerate. Theses two modes, distinguished by their opposite polarization and available only in antiferromagnets, give rise to a novel degree of freedom to encode and process information. We show that the spin wave polarization can be manipulated by an electric field induced Dzyaloshinskii-Moriya interaction and magnetic anisotropy. We propose a prototype spin wave field-effect transistor which realizes a gate-tunable magnonic analog of the Faraday effect, and demonstrate its application in THz signal modulation. Our findings open up the exciting possibility of digital data processing utilizing antiferromagnetic spin waves and enable the direct projection of optical computing concepts onto the mesoscopic scale.

  12. Transistorized pulse amplifiers (A.I.T.)

    International Nuclear Information System (INIS)

    The two amplifiers whose design and operation are described in this report have been studied for neutron detection units used in piles. They are designed to allow an important reduction of the volume and of the weight of the detector and its amplifier, and to simplify the operation of the detection assembly. To these characteristics can be added the mechanical and electrical robustness and the very reduced micro-phony. The first transistorized amplifier (AIT.1) is simple, very robust, and can be used for radioprotection installations. The second (AIT.4) has a better performance and makes it possible to replace the APT.2 in most of its applications (it has even been used satisfactorily in an apparatus where the micro-phony and the sensitivity to interference of the APT.2 made this latter unusable). (author)

  13. Transistor Level Implementation of Digital Reversible Circuits

    Directory of Open Access Journals (Sweden)

    K.Prudhvi Raj

    2015-12-01

    Full Text Available Now a days each and every electronic gadget is desi gning smartly and provides number of applications, so these designs dissipate high amount of power. Rever sible logic is becoming one of the best emerging de sign technologies having its applications in low power C MOS, Quantum computing and Nanotechnology. Reversible logic plays an important role in the des ign of energy efficient circuits. Adders and subtra ctors are the essential blocks of the computing systems. In this paper, reversible gates and circuits are de signed and implemented in CMOS and pass transistor logic u sing Mentor graphics backend tools. A four-bit ripp le carry adder/subtractor and an eight-bit reversible Carry Skip Adder are implemented and compared with the conventional circuits

  14. Performance Enhancement of Power Transistors and Radiation effect

    International Nuclear Information System (INIS)

    The main objective of this scientific research is studying the characteristic of bipolar junction transistor device and its performance under radiation fields and temperature effect as a control element in many power circuits. In this work we present the results of experimental measurements and analytical simulation of gamma – radiation effects on the electrical characteristics and operation of power transistor types 2N3773, 2N3055(as complementary silicon power transistor are designed for general-purpose switching and amplifier applications), three samples of each type were irradiated by gamma radiation with doses, 1 K rad, 5 K rad, 10 K rad, 30 K rad, and 10 Mrad, the experimental data are utilized to establish an analytical relation between the total absorbed dose of gamma irradiation and corresponding to effective density of generated charge in the internal structure of transistor, the electrical parameters which can be measured to estimate the generated defects in the power transistor are current gain, collector current and collected emitter leakage current , these changes cause the circuit to case proper functioning. Collector current and transconductance of each device are calibrated as a function of irradiated dose. Also the threshold voltage and transistor gain can be affected and also calibrated as a function of dose. A silicon NPN power transistor type 2N3773 intended for general purpose applications, were used in this work. It was designed for medium current and high power circuits. Performance and characteristic were discusses under temperature and gamma radiation doses. Also the internal junction thermal system of the transistor represented in terms of a junction thermal resistance (Rjth). The thermal resistance changed by ΔRjth, due to the external intended, also due to the gamma doses intended. The final result from the model analysis reveals that the emitter-bias configuration is quite stable by resistance ratio RB/RE. Also the current

  15. Precursor Parameter Identification for Insulated Gate Bipolar Transistor (IGBT) Prognostics

    Data.gov (United States)

    National Aeronautics and Space Administration — Precursor parameters have been identified to enable development of a prognostic approach for insulated gate bipolar transistors (IGBT). The IGBT were subjected to...

  16. Lateral PNP bipolar transistor with aiding field diffusions

    Science.gov (United States)

    Gallagher, R. C.; Mc Cann, D. H.

    1969-01-01

    Fabrication technique produces field aided lateral PNP transistors compatible with micropower switching circuits. The sub-collector diffusion is performed with phosphorus as the dopant and the epitaxy is grown using the higher temperature silicon tetrachloride process.

  17. Microwave field-efffect transistors theory, design, and application

    CERN Document Server

    Pengelly, Raymond

    1994-01-01

    This book covers the use of devices in microwave circuits and includes such topics as semiconductor theory and transistor performance, CAD considerations, intermodulation, noise figure, signal handling, S-parameter mapping, narrow- and broadband techniques, packaging and thermal considerations.

  18. Focused Ion Beam Induced Effects on MOS Transistor Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Abramo, Marsha T.; Antoniou, Nicholas; Campbell, Ann N.; Fleetwood, Daniel M.; Hembree, Charles E.; Jessing, Jeffrey R.; Soden, Jerry M.; Swanson, Scot E.; Tangyunyong, Paiboon; Vanderlinde, William E.

    1999-07-28

    We report on recent studies of the effects of 50 keV focused ion beam (FIB) exposure on MOS transistors. We demonstrate that the changes in value of transistor parameters (such as threshold voltage, V{sub t}) are essentially the same for exposure to a Ga+ ion beam at 30 and 50 keV under the same exposure conditions. We characterize the effects of FIB exposure on test transistors fabricated in both 0.5 {micro}m and 0.225 {micro}m technologies from two different vendors. We report on the effectiveness of overlying metal layers in screening MOS transistors from FIB-induced damage and examine the importance of ion dose rate and the physical dimensions of the exposed area.

  19. Influence of radiation defects on power bipolar transistor structures parameters

    International Nuclear Information System (INIS)

    The changes of main dynamic and static parameters of power transistor structures under 4 MeV electron and Co60 gamma-irradiation have considered. Main radiation defects (A-centers, divacancies, other dopant-defect complexes) in n-collector layer have been determined by DLTS. The interrelationship between the dynamic transistor parameters and the dominant defect (A-center) concentration has been established

  20. Sidewall penetration of dislocations in ion-implanted bipolar transistors

    International Nuclear Information System (INIS)

    Phosphorus-doped emitters have been formed by either conventional diffusion or implantation, anneal, and drive-in processes. Transmission electron microscopy and measurements of transistor characteristics were made to evaluate the two processes. Comparison of structures with similar dislocation densities indicated that the dislocations in the implanted structures penetrated the emitter-base sidewall, whereas the dislocations in the diffused structure were confined to the emitter region. The transistor with extended dislocations exhibited high leakage current and excess popcorn noise generating

  1. Wet Organic Field Effect Transistor as DNA sensor

    OpenAIRE

    Chiu, Yu-Jui

    2008-01-01

    Label-free detection of DNA has been successfully demonstrated on field effect transistor (FET) based devices. Since conducting organic materials was discovered and have attracted more and more research efforts by their profound advantages, this work will focus on utilizing an organic field effect transistor (OFET) as DNA sensor. An OFET constructed with a transporting fluidic channel, WetOFET, forms a fluid-polymer (active layer) interface where the probe DNA can be introduced. DNA hybridiza...

  2. Performance improvements in polysilicon source-gated transistors

    OpenAIRE

    Sporea, RA; Trainor, MJ; Young, ND; Shannon, JM; Silva, SRP

    2010-01-01

    The source-gated transistor (SGT) is a new type of transistor in which the current is controlled by a potential barrier at the source and by a gate which modulates the effective height of the source barrier. It is an ideal device architecture to be used with the low mobility materials typically applied to large area electronics, as it provides low saturation voltages and high output impedances. Furthermore, the high internal fields and low concentration of excess carriers lead to higher speed...

  3. Low-Field Behavior of Source-Gated Transistors

    OpenAIRE

    Shannon, JM; Sporea, RA; Georgakopoulos, S.; Shkunov, M.; Silva, SRP

    2013-01-01

    A physical description of low-field behavior of a Schottky source-gated transistor (SGT) is outlined where carriers crossing the source barrier by thermionic emission are restricted by JFET action in the pinch-off region at the drain end of the source. This mode of operation leads to transistor characteristics with low saturation voltage and high output impedance without the need for field relief at the edge of the Schottky source barrier and explains many characteristics of SGT observed expe...

  4. Asymmetric tunable tunneling magnetoresistance in single-electron transistors

    CERN Document Server

    Pirmann, M; Schön, G

    2000-01-01

    We show that the tunneling magnetoresistance (TMR) of a ferromagnetic single-electron transistor in the sequential tunneling regime shows asymmetric Coulomb blockade oscillations as a function of gate voltage if the individual junction-TMRs differ. The relative amplitude of these oscillations grows significantly if the bias voltage is increased, becoming as large as 30% when the bias voltage is comparable to the charging energy of the single-electron transistor. This might be useful for potential applications requiring a tunable TMR.

  5. Electrical properties of functionalized nanowire field effect transistors

    OpenAIRE

    Weitz, Ralf Thomas

    2008-01-01

    The utilization of functional organic materials holds great promise for applications in electronic devices. Semiconducting organic molecules are frequently used as channel material in field effect transistors, due to the ease by which they can be assembled as such components, and the ease with which their properties can be specifically tailored. An extension of the use of organic materials in field effect transistors with the potential to substantially improve the performance of such devices ...

  6. Resonant optical gating of suspended carbon nanotube transistor

    OpenAIRE

    McCoy, Robert; Anderson, Fredrick; Carter, Eric L.; Smith, Robinson L.

    2016-01-01

    Building smaller transistors with enhanced functionality is critical in extending the limits of Moores law and meeting the demands of the electronics industry. Here we demonstrate transistor operation in a suspended single carbon nanotube (CNT) using feedback-enabled radiation pressure of a near-field focused laser that enabled significant changes in conductivity of the CNT. Further, using in-situ tip-enhanced Raman spectroscopy, we show that the change in conductivity of over five orders in ...

  7. COULOMB BLOCKADE OSCILLATIONS OF Si SINGLE-ELECTRON TRANSISTORS

    Institute of Scientific and Technical Information of China (English)

    王太宏; 李宏伟; 周均铭

    2001-01-01

    Coulomb blockade oscillations of Si single-electron transistors, which are fabricated completely by the conventional photolithography technique, have been investigated. Most of the single-electron transistors clearly show Coulomb blockade oscillations and these oscillations can be periodic by applying negative voltages to the in-plane gates. A shift of the peak positions is observed at high temperatures. It is also found that the fluctuation of the peak spacing cannot be neglected.

  8. Progresses in organic field-effect transistors and molecular electronics

    Institute of Scientific and Technical Information of China (English)

    Wu Weiping; Xu Wei; Hu Wenping; Liu Yunqi; Zhu Daoben

    2006-01-01

    In the past years,organic semiconductors have been extensively investigated as electronic materials for organic field-effect transistors (OFETs).In this review,we briefly summarize the current status of organic field-effect transistors including materials design,device physics,molecular electronics and the applications of carbon nanotubes in molecular electronics.Future prospects and investigations required to improve the OFET performance are also involved.

  9. Reconfigurable quadruple quantum dots in a silicon nanowire transistor

    OpenAIRE

    Betz, A. C.; Tagliaferri, M. L. V.; Vinet, M.; Broström, M.; Sanquer, M.; Ferguson, A.J.; Gonzalez-Zalba, M. F.

    2016-01-01

    We present a novel reconfigurable metal-oxide-semiconductor multi-gate transistor that can host a quadruple quantum dot in silicon. The device consist of an industrial quadruple-gate silicon nanowire field-effect transistor. Exploiting the corner effect, we study the versatility of the structure in the single quantum dot and the serial double quantum dot regimes and extract the relevant capacitance parameters. We address the fabrication variability of the quadruple-gate approach which, paired...

  10. Single electron transistors with high quality superconducting niobium islands

    OpenAIRE

    Dolata, R.; Scherer, H.; Zorin, A. B.; J. Niemeyer

    2001-01-01

    Deep submicron Al-AlOx-Nb tunnel junctions and single electron transistors with niobium islands were fabricated by electron beam gun shadow evaporation. Using stencil masks consisting of the thermostable polymer polyethersulfone (PES) and germanium, high quality niobium patterns with good superconducting properties and a gap energy of up to 2Delta = 2.5 meV for the niobium were achieved. The I(U) characteristics of the transistors show special features due to tunneling of single Cooper pairs ...

  11. Gating a single-molecule transistor with individual atoms

    Science.gov (United States)

    Martínez-Blanco, Jesús; Nacci, Christophe; Erwin, Steven C.; Kanisawa, Kiyoshi; Locane, Elina; Thomas, Mark; von Oppen, Felix; Brouwer, Piet W.; Fölsch, Stefan

    2015-08-01

    Transistors, regardless of their size, rely on electrical gates to control the conductance between source and drain contacts. In atomic-scale transistors, this conductance is sensitive to single electrons hopping via individual orbitals. Single-electron transport in molecular transistors has been previously studied using top-down approaches to gating, such as lithography and break junctions. But atomically precise control of the gate--which is crucial to transistor action at the smallest size scales--is not possible with these approaches. Here, we used individual charged atoms, manipulated by a scanning tunnelling microscope, to create the electrical gates for a single-molecule transistor. This degree of control allowed us to tune the molecule into the regime of sequential single-electron tunnelling, albeit with a conductance gap more than one order of magnitude larger than observed previously. This unexpected behaviour arises from the existence of two different orientational conformations of the molecule, depending on its charge state. Our results show that strong coupling between these charge and conformational degrees of freedom leads to new behaviour beyond the established picture of single-electron transport in atomic-scale transistors.

  12. Ultra-high gain diffusion-driven organic transistor

    Science.gov (United States)

    Torricelli, Fabrizio; Colalongo, Luigi; Raiteri, Daniele; Kovács-Vajna, Zsolt Miklós; Cantatore, Eugenio

    2016-02-01

    Emerging large-area technologies based on organic transistors are enabling the fabrication of low-cost flexible circuits, smart sensors and biomedical devices. High-gain transistors are essential for the development of large-scale circuit integration, high-sensitivity sensors and signal amplification in sensing systems. Unfortunately, organic field-effect transistors show limited gain, usually of the order of tens, because of the large contact resistance and channel-length modulation. Here we show a new organic field-effect transistor architecture with a gain larger than 700. This is the highest gain ever reported for organic field-effect transistors. In the proposed organic field-effect transistor, the charge injection and extraction at the metal-semiconductor contacts are driven by the charge diffusion. The ideal conditions of ohmic contacts with negligible contact resistance and flat current saturation are demonstrated. The approach is general and can be extended to any thin-film technology opening unprecedented opportunities for the development of high-performance flexible electronics.

  13. Large scale electromechanical transistor with application in mass sensing

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Leisheng; Li, Lijie, E-mail: L.Li@swansea.ac.uk [Multidisciplinary Nanotechnology Centre, College of Engineering, Swansea University, Swansea SA2 8PP (United Kingdom)

    2014-12-07

    Nanomechanical transistor (NMT) has evolved from the single electron transistor, a device that operates by shuttling electrons with a self-excited central conductor. The unfavoured aspects of the NMT are the complexity of the fabrication process and its signal processing unit, which could potentially be overcome by designing much larger devices. This paper reports a new design of large scale electromechanical transistor (LSEMT), still taking advantage of the principle of shuttling electrons. However, because of the large size, nonlinear electrostatic forces induced by the transistor itself are not sufficient to drive the mechanical member into vibration—an external force has to be used. In this paper, a LSEMT device is modelled, and its new application in mass sensing is postulated using two coupled mechanical cantilevers, with one of them being embedded in the transistor. The sensor is capable of detecting added mass using the eigenstate shifts method by reading the change of electrical current from the transistor, which has much higher sensitivity than conventional eigenfrequency shift approach used in classical cantilever based mass sensors. Numerical simulations are conducted to investigate the performance of the mass sensor.

  14. Large scale electromechanical transistor with application in mass sensing

    International Nuclear Information System (INIS)

    Nanomechanical transistor (NMT) has evolved from the single electron transistor, a device that operates by shuttling electrons with a self-excited central conductor. The unfavoured aspects of the NMT are the complexity of the fabrication process and its signal processing unit, which could potentially be overcome by designing much larger devices. This paper reports a new design of large scale electromechanical transistor (LSEMT), still taking advantage of the principle of shuttling electrons. However, because of the large size, nonlinear electrostatic forces induced by the transistor itself are not sufficient to drive the mechanical member into vibration—an external force has to be used. In this paper, a LSEMT device is modelled, and its new application in mass sensing is postulated using two coupled mechanical cantilevers, with one of them being embedded in the transistor. The sensor is capable of detecting added mass using the eigenstate shifts method by reading the change of electrical current from the transistor, which has much higher sensitivity than conventional eigenfrequency shift approach used in classical cantilever based mass sensors. Numerical simulations are conducted to investigate the performance of the mass sensor

  15. A final report for: Gallium arsenide P-I-N detectors for high-sensitivity imaging of thermal neutrons

    International Nuclear Information System (INIS)

    This SBIR Phase I developed neutron detectors made FR-om gallium arsenide (GaAs) p-type/ intrinsic/n-type (P-I-N) diodes grown by metalorganic chemical vapor deposition (MOCVD) onto semi-insulating (S1) bulk GaAs wafers. A layer of isotonically enriched boron-10 evaporated onto the FR-ont surface serves to convert incoming neutrons into lithium ions and a 1.47 MeV alpha particle which creates electron-hole pairs that are detected by the GaAs diode. Various thicknesses of ''intrinsic'' (I) undoped GaAs were tested, as was use of a back-surface field (BSF) formed FR-om a layer of AlxGa1-xAs. Schottky-barrier diodes formed FR-om the same structures without the p+ GaAs top layer were tested as a comparison. After mesa etching and application of contacts, devices were tested in visible light before application of the boron coating. Internal quantum efficiency (IQE) of the best diode near the GaAs bandedge is over 90%. The lowest dark current measured is 1 x 10-12 amps at -1 V on a 3mm x 3mm diode, or a density of 1.1 x 10-11 amps cm-2, with many of the diode structures tested having nearly similar results. The PIN diodes were significantly better than the Schottky barrier device, which had six orders of magnitude higher dark current. Diodes were characterized in terms of their current-mode response to 5.5 MeV alpha particles FR-om 241-Americium. These radiation-induced currents were as high as 9.78 x 10-7 A cm-1 on a PIN device with an AlxGa1-xAs BSF. Simple PIN diodes had currents as high as 2.44 x 10-7 A cm-2, with thicker undoped layers showing better sensitivity. Boron coatings were applied, and response to neutrons tested at University of Michigan by Dr. Doug McGregor. Devices with PIN and Schottky barrier designs showed neutron detection efficiencies as high as 2% on 5 (micro)m thick devices, with no need for external bias voltages. PIN diodes showed higher breakdown voltages and lower noise characteristics than did the Schottky barrier design. Uniformity of

  16. Thermal Runaway Robustness of SiC VJFETs

    OpenAIRE

    Ouaida, Rémy; Buttay, Cyril; Hoang, Anh Dung; Riva, Raphaël; Bergogne, Dominique; Morel, Hervé; Raynaud, Christophe; Morel, Florent

    2013-01-01

    Silicon Carbide (SiC) Junction-Field Effect Transistors (JFETs) are attractive devices for power electronics. Their high temperature capability should allow them to operate with a reduced cooling system. However, experiments described in this paper conclude to the existence of runaway conditions in which these transistors will reach destructive temperatures.

  17. Ternary arsenides based on platinum–indium and palladium–indium fragments of the Cu{sub 3}Au-type: Crystal structures and chemical bonding

    Energy Technology Data Exchange (ETDEWEB)

    Zakharova, Elena Yu.; Andreeva, Natalia A.; Kazakov, Sergey M. [Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1-3, GSP-1, 119991 Moscow (Russian Federation); Kuznetsov, Alexey N., E-mail: alexei@inorg.chem.msu.ru [Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1-3, GSP-1, 119991 Moscow (Russian Federation); N.S. Kurnakov Institute of General and Inorganic Chemistry of Russian Academy of Sciences, Leninskii pr. 31, 119991 Moscow (Russian Federation)

    2015-02-05

    Highlights: • Three metal-rich platinum–indium and palladium–indium arsenides were synthesized. • Their crystal structures were determined from powder XRD. • Electronic structures and bonding were studied using DFT/FP-LAPW calculations. • Multi-centered Pt–In or Pd–In bonding was revealed using ELF and ELI-D analysis. • Extra pairwise Pt–Pt interactions are observed only for Pt-based compounds. - Abstract: Three metal-rich palladium–indium and platinum–indium arsenides, Pd{sub 5}InAs, Pt{sub 5}InAs, and Pt{sub 8}In{sub 2}As, were synthesized using a high-temperature ampoule technique. Their crystal structures were determined from Rietveld analysis of powder diffraction data. All the compounds crystallize in tetragonal system with P4/mmm space group (Pd{sub 5}InAs: a = 3.9874(1) Å, c = 6.9848(2) Å, Z = 1, R{sub p} = 0.053; R{sub b} = 0.013; Pt{sub 5}InAs: a = 3.9981(2) Å, c = 7.0597(4) Å, Z = 1, R{sub p} = 0.058, R{sub b} = 0.016; Pt{sub 8}In{sub 2}As: a = 3.9872(3) Å, c = 11.1129(7) Å, Z = 1, R{sub p} = 0.047; R{sub b} = 0.014). The first two compounds belong to the Pd{sub 5}TlAs structure type, while the third one is isotypic with the recently discovered Pd{sub 8}In{sub 2}Se. Main structural units in all arsenides are indium-centered [TM{sub 12}In] cuboctahedra (TM = Pd, Pt) of the Cu{sub 3}Au type, single- and double-stacked along the c axis in TM{sub 5}InAs and Pt{sub 8}In{sub 2}As, respectively, alternating with [TM{sub 8}As] rectangular prisms. DFT electronic structure calculations predict all three compounds to be 3D metallic conductors and Pauli-like paramagnets. According to the bonding analysis based on the electron localization function and electron localizability indicator topologies, all compounds feature multi-centered interactions between transition metal and indium in their heterometallic fragments. Additionally, pairwise interactions between platinum atoms are also observed, indicating a somewhat more localized bonding

  18. Fast Flexible Transistors with a Nanotrench Structure

    Science.gov (United States)

    Seo, Jung-Hun; Ling, Tao; Gong, Shaoqin; Zhou, Weidong; Ma, Alice L.; Guo, L. Jay; Ma, Zhenqiang

    2016-04-01

    The simplification of fabrication processes that can define very fine patterns for large-area flexible radio-frequency (RF) applications is very desirable because it is generally very challenging to realize submicron scale patterns on flexible substrates. Conventional nanoscale patterning methods, such as e-beam lithography, cannot be easily applied to such applications. On the other hand, recent advances in nanoimprinting lithography (NIL) may enable the fabrication of large-area nanoelectronics, especially flexible RF electronics with finely defined patterns, thereby significantly broadening RF applications. Here we report a generic strategy for fabricating high-performance flexible Si nanomembrane (NM)-based RF thin-film transistors (TFTs), capable of over 100 GHz operation in theory, with NIL patterned deep-submicron-scale channel lengths. A unique 3-dimensional etched-trench-channel configuration was used to allow for TFT fabrication compatible with flexible substrates. Optimal device parameters were obtained through device simulation to understand the underlying device physics and to enhance device controllability. Experimentally, a record-breaking 38 GHz maximum oscillation frequency fmax value has been successfully demonstrated from TFTs with a 2 μm gate length built with flexible Si NM on plastic substrates.

  19. Transistor Level Circuit Experiments using Evolvable Hardware

    Science.gov (United States)

    Stoica, A.; Zebulum, R. S.; Keymeulen, D.; Ferguson, M. I.; Daud, Taher; Thakoor, A.

    2005-01-01

    The Jet Propulsion Laboratory (JPL) performs research in fault tolerant, long life, and space survivable electronics for the National Aeronautics and Space Administration (NASA). With that focus, JPL has been involved in Evolvable Hardware (EHW) technology research for the past several years. We have advanced the technology not only by simulation and evolution experiments, but also by designing, fabricating, and evolving a variety of transistor-based analog and digital circuits at the chip level. EHW refers to self-configuration of electronic hardware by evolutionary/genetic search mechanisms, thereby maintaining existing functionality in the presence of degradations due to aging, temperature, and radiation. In addition, EHW has the capability to reconfigure itself for new functionality when required for mission changes or encountered opportunities. Evolution experiments are performed using a genetic algorithm running on a DSP as the reconfiguration mechanism and controlling the evolvable hardware mounted on a self-contained circuit board. Rapid reconfiguration allows convergence to circuit solutions in the order of seconds. The paper illustrates hardware evolution results of electronic circuits and their ability to perform under 230 C temperature as well as radiations of up to 250 kRad.

  20. Fast Flexible Transistors with a Nanotrench Structure.

    Science.gov (United States)

    Seo, Jung-Hun; Ling, Tao; Gong, Shaoqin; Zhou, Weidong; Ma, Alice L; Guo, L Jay; Ma, Zhenqiang

    2016-01-01

    The simplification of fabrication processes that can define very fine patterns for large-area flexible radio-frequency (RF) applications is very desirable because it is generally very challenging to realize submicron scale patterns on flexible substrates. Conventional nanoscale patterning methods, such as e-beam lithography, cannot be easily applied to such applications. On the other hand, recent advances in nanoimprinting lithography (NIL) may enable the fabrication of large-area nanoelectronics, especially flexible RF electronics with finely defined patterns, thereby significantly broadening RF applications. Here we report a generic strategy for fabricating high-performance flexible Si nanomembrane (NM)-based RF thin-film transistors (TFTs), capable of over 100 GHz operation in theory, with NIL patterned deep-submicron-scale channel lengths. A unique 3-dimensional etched-trench-channel configuration was used to allow for TFT fabrication compatible with flexible substrates. Optimal device parameters were obtained through device simulation to understand the underlying device physics and to enhance device controllability. Experimentally, a record-breaking 38 GHz maximum oscillation frequency fmax value has been successfully demonstrated from TFTs with a 2 μm gate length built with flexible Si NM on plastic substrates. PMID:27094686

  1. Advanced insulated gate bipolar transistor gate drive

    Science.gov (United States)

    Short, James Evans; West, Shawn Michael; Fabean, Robert J.

    2009-08-04

    A gate drive for an insulated gate bipolar transistor (IGBT) includes a control and protection module coupled to a collector terminal of the IGBT, an optical communications module coupled to the control and protection module, a power supply module coupled to the control and protection module and an output power stage module with inputs coupled to the power supply module and the control and protection module, and outputs coupled to a gate terminal and an emitter terminal of the IGBT. The optical communications module is configured to send control signals to the control and protection module. The power supply module is configured to distribute inputted power to the control and protection module. The control and protection module outputs on/off, soft turn-off and/or soft turn-on signals to the output power stage module, which, in turn, supplies a current based on the signal(s) from the control and protection module for charging or discharging an input capacitance of the IGBT.

  2. Transistor needle chip for recording in brain tissue

    Science.gov (United States)

    Felderer, Florian; Fromherz, Peter

    2011-07-01

    We report on a proof-of-principle experiment for the direct interfacing of transistors with intact brain tissue. A transistor needle chip (TNC) with a TiO2 surface is fabricated from a silicon-on-insulator wafer and impaled into an acute brain slice cut from hippocampus of the rat. While stimulating the Schaffer collateral, a local field potential is recorded in stratum radiatum of the CA1 region with field-effect transistors in the central part of the slice where the tissue is not damaged by the cutting process. After the impalement, the signal amplitude is small. Within an hour, it increases to a stable level around -2 mV as is recorded with a conventional micropipette electrode. The recovery indicates that the tissue is able to adapt to the impaled chip. Upon repeated impalements at the same position, the large signal is observed without delay. A profile of the transistor signal across the slice is due to the boundary conditions of a brain slice with both surfaces held near ground potential. The experiments with the TNC prototype are a basis for the development of silicon needle chips with a large multi-transistor array (MTA) for applications in brain-computer interfacing.

  3. Use of NPN bipolar transistors for silicon equivalent neutron damage

    International Nuclear Information System (INIS)

    With the closing of the Northrop Triga Reactor, Northrop shifted its neutron irradiations to the several government Fast Burst Reactors. As a control, an inexpensive NPN bipolar transistor was chosen to monitor the silicon equivalent damage created by the differing neutron spectra. Noticeable biases occurred between the comparisons with 1 Mev silicon equivalent dosimetry reported by the several facilities and the damage observed in the monitor transistors and other semiconductors being irradiated. A special effort was committed to automate the measurement of the monitor transistors. Their behavior was then studied and quantified so that a more precise determination of the neutron fluence could be obtained. The techniques needed for accurate read-out of fluences from monitor transistors, with supporting data, is presented. The variabilities are mostly related to the choice of monitor transistor, test conditions, ambient and self-heating, and timing/annealing of the measurements. The occurrence of reverse annealing, varying with measurement current, is detailed. Also the monitoring of VBE as a thermometer to correct the damage factor to a standard temperature is noted. The electrical measurement errors have been made negligible. Some preliminary comparisons are given for the several facilities, using their historic 1 Mev (Si) sulfur/conversions. These comparisons do not include any adjustments for the biases developed by experiment positioning or recent changes in the silicon 1 Mev damage equivalence curve

  4. Subthreshold Leakage Minimization in MOSFET using Sleep Transistor Circuit

    Directory of Open Access Journals (Sweden)

    Shailesh Kumar Mukati

    2014-05-01

    Full Text Available The excessive power consumption has become one in all the first hindrances to the more advances of CMOS integrated circuits. Low power circuit style is a crucial analysis space. there are 3 primary stimuli for low power circuit design: setting friendly inexperienced computing, battery life extension for mobile applications, and rising self-sufficing battery replacement free applications like intelligent sensing element nodes. The leakage current in MOSFET is due to subthreshold leakage current due to parasitic pn junctions. The sleep transistor is use between CMOS logic and supply rail. Our technique, sleep transistor square measure placed between the circuits offer and provide rails to show off the run current flow throughout idle time this will be done by victimization one PMOS transistor and one NMOS transistor nonparallel with the transistors of every logic block to make a virtual ground and a virtual power supply. constant estimation victimization town simulation will acquire a comparatively correct estimation of the run distribution; but, this methodology needs an extended simulation time and is therefore computationally expensive

  5. Transistor reset preamplifier for high-rate high-resolution spectroscopy

    International Nuclear Information System (INIS)

    Pulsed transistor reset of high resolution charge sensitive preamplifiers used in cooled semiconductor spectrometers can sometimes have an advantage over pulsed light reset systems. Several versions of transistor reset spectrometers using both silicon and germanium detectors have been built. This paper discusses the advantages of the transistor reset system and illustrates several configurations of the packages used for the FET and reset transistor. It also describes the preamplifer circuit and shows the performance of the spectrometer at high rates

  6. Characterisation of silicon carbide schottky diodes and coolmos transistors at high temperature

    OpenAIRE

    Khatir, Z.; L. Dupont; Lefebvre, S.; Bontemps, S.; MEURET,R

    2004-01-01

    The highly doping level of the base region of coolmos transistors allows higher temperature operations than with conventional silicon transistors having the same blocking voltage. In this paper, the temperature influence on different sic schottky diodes and silicon coolmos transistors characteritics is discussed. Comparisons are made and the results on the behaviour of sic schottky diodes and coolmos transistors in the on-state and in switching operations.

  7. Indium Arsenide Nanowires

    DEFF Research Database (Denmark)

    Madsen, Morten Hannibal

    substrates. The crystal structure of the NWs has also been investigated, and a method for obtaining pure wurtzite NWs with a well controlled diameter and length is presented. For self-assisted growth of InAs NWs a method for enhanced control of the nanowire morphology by pre-treatment of the oxide layer...... is presented. A series of experiments with formation of a droplet on top of the wires has been carried out and pyramidal shaped structures at the NW top with pure zinc blende crystal structure are observed. A novel in-situ experiment with fabrication of NWs and simultanous characterization using x...

  8. Gallium arsenide pixel detectors

    Energy Technology Data Exchange (ETDEWEB)

    Bates, R.; DaVia, C.; O`Shea, V.; Raine, C.; Smith, K. [Glasgow Univ. (United Kingdom). Dept. of Physics and Astronomy; Campbell, M.; Cantatore, E.; Heijne, E.M.; Middelkamp, P.; Ropotar, I.; Scharfetter, L.; Snoeys, W. [CERN, ECP Div., CH-1211 Geneva 23 (Switzerland); D`Auria, S.; Papa, C. del [Department of Physics, University of Udine and INFN Trieste, Via delle Scienze 208, I-33100 Udine (Italy); RD8 Collaboration

    1998-06-01

    GaAs detectors can be fabricated with bidimensional single-sided electrode segmentation. They have been successfully bonded using flip-chip technology to the Omega-3 silicon read-out chip. We present here the design features of the GaAs pixel detectors and results from a test performed at the CERN SpS with a 120 GeV {pi}{sup -} beam. The detection efficiency was 99.2% with a nominal threshold of 5000 e{sup -}. (orig.) 10 refs.

  9. Theoretical values of various parameters in the Gummel-Poon model of a bipolar junction transistor

    Science.gov (United States)

    Benumof, R.; Zoutendyk, J.

    1986-01-01

    Various parameters in the Gummel-Poon model of a bipolar junction transistor are expressed in terms of the basic structure of a transistor. A consistent theoretical approach is used which facilitates an understanding of the foundations and limitations of the derived formulas. The results enable one to predict how changes in the geometry and composition of a transistor would affect performance.

  10. Development and Experimental Evaluation of an Automated Multi-Media Course on Transistors.

    Science.gov (United States)

    Whitted, J.H., Jr.; And Others

    A completely automated multi-media self-study program for teaching a portion of electronic solid-state fundamentals was developed. The subject matter areas included were fundamental theory of transistors, transistor amplifier fundamentals, and simple mathematical analysis of transistors including equivalent circuits, parameters, and characteristic…

  11. Investigation of Impact of the Gate Circuitry on IGBT Transistor Dynamic Parameters

    Directory of Open Access Journals (Sweden)

    Vytautas Bleizgys

    2011-03-01

    Full Text Available The impact of Insulated Gate Bipolar Transistor driver circuit parameters on the rise and fall time of the collector current and voltage collector-emitter was investigated. The influence of transistor driver circuit parameters on heating of Insulated Gate Bipolar Transistors was investigated as well.Article in Lithuanian

  12. Vertically aligned carbon nanotube field-effect transistors

    KAUST Repository

    Li, Jingqi

    2012-10-01

    Vertically aligned carbon nanotube field-effect transistors (CNTFETs) have been developed using pure semiconducting carbon nanotubes. The source and drain were vertically stacked, separated by a dielectric, and the carbon nanotubes were placed on the sidewall of the stack to bridge the source and drain. Both the effective gate dielectric and gate electrode were normal to the substrate surface. The channel length is determined by the dielectric thickness between source and drain electrodes, making it easier to fabricate sub-micrometer transistors without using time-consuming electron beam lithography. The transistor area is much smaller than the planar CNTFET due to the vertical arrangement of source and drain and the reduced channel area. © 2012 Elsevier Ltd. All rights reserved.

  13. Integrated logic circuits using single-atom transistors.

    Science.gov (United States)

    Mol, J A; Verduijn, J; Levine, R D; Remacle, F; Rogge, S

    2011-08-23

    Scaling down the size of computing circuits is about to reach the limitations imposed by the discrete atomic structure of matter. Reducing the power requirements and thereby dissipation of integrated circuits is also essential. New paradigms are needed to sustain the rate of progress that society has become used to. Single-atom transistors, SATs, cascaded in a circuit are proposed as a promising route that is compatible with existing technology. We demonstrate the use of quantum degrees of freedom to perform logic operations in a complementary-metal-oxide-semiconductor device. Each SAT performs multilevel logic by electrically addressing the electronic states of a dopant atom. A single electron transistor decodes the physical multivalued output into the conventional binary output. A robust scalable circuit of two concatenated full adders is reported, where by utilizing charge and quantum degrees of freedom, the functionality of the transistor is pushed far beyond that of a simple switch. PMID:21808050

  14. Calculating drain delay in high electron mobility transistors

    Science.gov (United States)

    Coffie, R.

    2015-12-01

    An expression for the signal delay (drain delay) associated with electrons traveling through the gate-drain depletion region has been obtained for nonuniform electron velocity. Due to the presence of the gate metal, the signal delay through the gate-drain depletion region was shown to be larger than the signal delay in the base-collector depletion region of a bipolar transistor when equal depletion lengths and velocity profiles were assumed. Drain delay is also shown to be larger in transistors with field plates (independent of field plate connection) compared to transistors without field plates when equal depletion lengths and velocity profiles were assumed. For the case of constant velocity, two expressions for the proportionality constant relating drain delay and electron transit time across the depletion were obtained.

  15. Nanowire transistors physics of devices and materials in one dimension

    CERN Document Server

    Colinge, Jean-Pierre

    2016-01-01

    From quantum mechanical concepts to practical circuit applications, this book presents a self-contained and up-to-date account of the physics and technology of nanowire semiconductor devices. It includes a unified account of the critical ideas central to low-dimensional physics and transistor physics which equips readers with a common framework and language to accelerate scientific and technological developments across the two fields. Detailed descriptions of novel quantum mechanical effects such as quantum current oscillations, the metal-to-semiconductor transition and the transition from classical transistor to single-electron transistor operation are described in detail, in addition to real-world applications in the fields of nanoelectronics, biomedical sensing techniques, and advanced semiconductor research. Including numerous illustrations to help readers understand these phenomena, this is an essential resource for researchers and professional engineers working on semiconductor devices and materials in ...

  16. Fully printed metabolite sensor using organic electrochemical transistor

    Science.gov (United States)

    Scheiblin, Gaëtan; Aliane, Abdelkader; Coppard, Romain; Owens, Róisín. M.; Mailley, Pascal; Malliaras, George G.

    2015-08-01

    As conducting polymer based devices, organic electrochemical transistors (OECTs) are suited for printing process. The convenience of the screen-printing techniques allowed us to design and fabricate OECTs with a selected design and using different gate material. Depending on the material used, we were able to tune the transistor for different biological application. Ag/AgCl gate provided transistor with good transconductance, and electrochemical sensitivity to pH was provided by polyaniline ink. Finally, we validate the enzymatic sensing of glucose and lactate with a Poly(3,4-ethylene dioxythiophene) doped with poly(styrene sulfonate) (PEDOT:PSS) gate often used due to its biocompatible properties. The screen-printing process allowed us to fabricate a large amount of devices in a short period of time, using only commercially available grades of ink, showing by this way the possible transfer to industrial purpose.

  17. Single-Photon Transistor Using a Förster Resonance

    Science.gov (United States)

    Tiarks, Daniel; Baur, Simon; Schneider, Katharina; Duerr, Stephan; Rempe, Gerhard

    2015-05-01

    An all-optical transistor is a device in which a gate light pulse switches the transmission of a target light pulse with a gain above unity. The gain quantifies the change of the transmitted target photon number per incoming gate photon. We study the quantum limit of one incoming gate photon and observe a gain of 20. The gate pulse is stored as a Rydberg excitation in an ultracold gas. The transmission of the subsequent target pulse is suppressed by Rydberg blockade which is enhanced by a Förster resonance. The detected target photons reveal in a single shot with a fidelity above 0.86 whether a Rydberg excitation was created during the gate pulse. The gain offers the possibility to distribute the transistor output to the inputs of many transistors, thus making complex computational tasks possible.

  18. Transistorized PWM inverter-induction motor drive system

    Science.gov (United States)

    Peak, S. C.; Plunkett, A. B.

    1982-01-01

    This paper describes the development of a transistorized PWM inverter-induction motor traction drive system. A vehicle performance analysis was performed to establish the vehicle tractive effort-speed requirements. These requirements were then converted into a set of inverter and motor specifications. The inverter was a transistorized three-phase bridge using General Electric power Darlington transistors. The description of the design and development of this inverter is the principal object of this paper. The high-speed induction motor is a design which is optimized for use with an inverter power source. The primary feedback control is a torque angle control with voltage and torque outer loop controls. A current-controlled PWM technique is used to control the motor voltage. The drive has a constant torque output with PWM operation to base motor speed and a constant horsepower output with square wave operation to maximum speed. The drive system was dynamometer tested and the results are presented.

  19. Planar transistors and impatt diodes with ion implantation

    International Nuclear Information System (INIS)

    Low frequency planar npn and pnp transistors have been developed in which the base and emitter have been fabricated using ion implantation of boron and phosphorus by a drive-in diffusion. Electrical parameters of the transistors are comparable with conventionally produced transistors; the noise figure was improved and production tolerances were significantly reduced. Silicon-impatt diodes for the microwave range were also fabricated with implanted pn junctions and tested for their high frequency characteristics. These diodes, made in an improved upside down technology, delivered output power up to 40 mW (burn out power) at 30 GHz. Reverse leakage current and current carrying capability of these diodes were comparable to diffused structures. (orig.) 891 ORU 892 MB

  20. Effects on focused ion beam irradiation on MOS transistors

    International Nuclear Information System (INIS)

    The effects of irradiation from a focused ion beam (FIB) system on MOS transistors are reported systematically for the first time. Three MOS transistor technologies, with 0.5, 1, and 3 μm minimum feature sizes and with gate oxide thicknesses ranging from 11 to 50 nm, were analyzed. Significant shifts in transistor parameters (such as threshold voltage, transconductance, and mobility) were observed following irradiation with a 30 keV Ga+ focused ion beam with ion doses varying by over 5 orders of magnitude. The apparent damage mechanism (which involved the creation of interface traps, oxide trapped charge, or both) and extent of damage were different for each of the three technologies investigated

  1. A single photoelectron transistor for quantum optical communications

    CERN Document Server

    Kosaka, H; Robinson, H D; Bandaru, P; Makita, K; Yablonovitch, E B; Kosaka, Hideo; Rao, Deepak S.; Robinson, Hans D.; Bandaru, Prabhakar; Makita, Kikuo; Yablonovitch, Eli

    2003-01-01

    A single photoelectron can be trapped and its photoelectric charge detected by a source/drain channel in a transistor. Such a transistor photodetector can be useful for flagging the safe arrival of a photon in a quantum repeater. The electron trap can be photo-ionized and repeatedly reset for the arrival of successive individual photons. This single photoelectron transistor (SPT) operating at the lambda = 1.3 mu m tele-communication band, was demonstrated by using a windowed-gate double-quantum-well InGaAs/InAlAs/InP heterostructure that was designed to provide near-zero electron g-factor. The g-factor engineering allows selection rules that would convert a photon's polarization to an electron spin polarization. The safe arrival of the photo-electric charge would trigger the commencement of the teleportation algorithm.

  2. Conductance of quantum interference transistors in parallel and in series

    Science.gov (United States)

    Nikolić, K.; Nikolić, P.; Šordan, R.

    1999-07-01

    We theoretically study the electronic conductance G and the current-voltage characteristics of two quantum interference transistors in parallel and in series. We use two different definitions of conductance, G ˜ T and G ˜ T / R. Neither can reproduce the classical additivity law in the case of coherent transport due to quantum interference for the elements in series and quasibound states when elements are in parallel. In the case of two transistors in series, we find that the quantity T / R only qualitatively better represents the additivity law, which is probably expected because this model avoids counting the contact resistance twice. However, for the parallel configuration of transistors, the conductance is almost additive for the majority of energies when G ˜ T, except for the single-mode regime. Possible use of these configurations in digital electronics for basic logic functions is discussed.

  3. Effects on focused ion beam irradiation on MOS transistors

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, A.N.; Peterson, K.A.; Fleetwood, D.M.; Soden, J.M.

    1997-04-01

    The effects of irradiation from a focused ion beam (FIB) system on MOS transistors are reported systematically for the first time. Three MOS transistor technologies, with 0.5, 1, and 3 {mu}m minimum feature sizes and with gate oxide thicknesses ranging from 11 to 50 nm, were analyzed. Significant shifts in transistor parameters (such as threshold voltage, transconductance, and mobility) were observed following irradiation with a 30 keV Ga{sup +} focused ion beam with ion doses varying by over 5 orders of magnitude. The apparent damage mechanism (which involved the creation of interface traps, oxide trapped charge, or both) and extent of damage were different for each of the three technologies investigated.

  4. Activation Energy of Polycrystalline Silicon Thin Film Transistor

    Directory of Open Access Journals (Sweden)

    B.P. Tyagi

    2011-01-01

    Full Text Available The activation energy of a poly-Si thin film transistor is observed to be influenced by the grain size, trap state density and the inversion layer thickness. The present study aims to investigate these parameters theoretically so as to explore optimum conditions for the working of a polycrystalline silicon thin film transistor. Our computations have revealed that the activation energy decreases with the increase of gate bias for all values of grain size, trap states density and the inversion layer thickness. These findings are compared with the experimental results.

  5. Sandwich double gate vertical tunneling field-effect transistor

    Science.gov (United States)

    Wang, Ying; Zhang, Wen-hao; Yu, Cheng-hao; Cao, Fei

    2016-05-01

    In this work, a sandwich vertical tunnel field effect transistor (SDG-VTFET) is presented and studied. Since the dominant carrier tunneling of SDG-VFET occurs in a direction that is in line with the gate field, high ON-state current and steep subthreshold slope are observed. Comparisons between SDG-VFET and double gate tunnel field effect transistor are made to clarify advantages of SDG-VTFET. The simulation results of our work show that SDG-VTFET has stronger gate control, steeper subthreshold slope and higher ON-state current. The device plays a promising candidate for future low power circuit applications.

  6. Copper oxide transistor on copper wire for e-textile

    Science.gov (United States)

    Han, Jin-Woo; Meyyappan, M.

    2011-05-01

    A Cu2O-based field effect transistor was fabricated on Cu wire. Thermal oxidation of Cu forms Cu-Cu2O core-shell structure, where the metal-semiconductor Schottky junction was used as a gate barrier with Pt Ohmic contacts for source and drain. The device was coated with polydimethylsiloxane (PDMS) to protect from contamination and demonstrated as a humidity sensor. The cylindrical structure of the Cu wire and the transistor function enable embedding of simple circuits into textile which can potentially offer smart textile for wearable computing, environmental sensing, and monitoring of human vital signs.

  7. Characterization of a Common-Source Amplifier Using Ferroelectric Transistors

    Science.gov (United States)

    Hunt, Mitchell; Sayyah, Rana; MacLeond, Todd C.; Ho, Pat D.

    2010-01-01

    This paper presents empirical data that was collected through experiments using a FeFET in the established common-source amplifier circuit. The unique behavior of the FeFET lends itself to interesting and useful operation in this widely used common-source amplifier. The paper examines the effect of using a ferroelectric transistor for the amplifier. It also examines the effects of varying load resistance, biasing, and input voltages on the output signal and gives several examples of the output of the amplifier for a given input. The difference between a commonsource amplifier using a ferroelectric transistor and that using a MOSFET is addressed.

  8. Recent progress in photoactive organic field-effect transistors

    OpenAIRE

    Yutaka Wakayama; Ryoma Hayakawa; Hoon-Seok Seo

    2014-01-01

    Recent progress in photoactive organic field-effect transistors (OFETs) is reviewed. Photoactive OFETs are divided into light-emitting (LE) and light-receiving (LR) OFETs. In the first part, LE-OFETs are reviewed from the viewpoint of the evolution of device structures. Device performances have improved in the last decade with the evolution of device structures from single-layer unipolar to multi-layer ambipolar transistors. In the second part, various kinds of LR-OFETs are featured. These ar...

  9. All diamond self-aligned thin film transistor

    Science.gov (United States)

    Gerbi, Jennifer

    2008-07-01

    A substantially all diamond transistor with an electrically insulating substrate, an electrically conductive diamond layer on the substrate, and a source and a drain contact on the electrically conductive diamond layer. An electrically insulating diamond layer is in contact with the electrically conductive diamond layer, and a gate contact is on the electrically insulating diamond layer. The diamond layers may be homoepitaxial, polycrystalline, nanocrystalline or ultrananocrystalline in various combinations.A method of making a substantially all diamond self-aligned gate transistor is disclosed in which seeding and patterning can be avoided or minimized, if desired.

  10. Nanophotonic quantum computer based on atomic quantum transistor

    Science.gov (United States)

    Andrianov, S. N.; Moiseev, S. A.

    2015-10-01

    We propose a scheme of a quantum computer based on nanophotonic elements: two buses in the form of nanowaveguide resonators, two nanosized units of multiatom multiqubit quantum memory and a set of nanoprocessors in the form of photonic quantum transistors, each containing a pair of nanowaveguide ring resonators coupled via a quantum dot. The operation modes of nanoprocessor photonic quantum transistors are theoretically studied and the execution of main logical operations by means of them is demonstrated. We also discuss the prospects of the proposed nanophotonic quantum computer for operating in high-speed optical fibre networks.

  11. Enhancement of Transistor-to-Transistor Variability Due to Total Dose Effects in 65-nm MOSFETs

    CERN Document Server

    Gerardin, S; Cornale, D; Ding, L; Mattiazzo, S; Paccagnella, A; Faccio, F; Michelis, S

    2015-01-01

    We studied device-to-device variations as a function of total dose in MOSFETs, using specially designed test structures and procedures aimed at maximizing matching between transistors. Degradation in nMOSFETs is less severe than in pMOSFETs and does not show any clear increase in sample-to-sample variability due to the exposure. At doses smaller than 1 Mrad( SiO2) variability in pMOSFETs is also practically unaffected, whereas at very high doses-in excess of tens of Mrad( SiO2)-variability in the on-current is enhanced in a way not correlated to pre-rad variability. The phenomenon is likely due to the impact of random dopant fluctuations on total ionizing dose effects.

  12. Thermal analytic model of current gain for bipolar junction transistor-bipolar static induction transistor compound device

    Institute of Scientific and Technical Information of China (English)

    Zhang You-Run; Zhang Bo; Li Ze-Hong; Lai Chang-Jin; Li Zhao-Ji

    2009-01-01

    This paper proposes a thermal analytical model of current gain for bipolar junction transistor-bipolar static induction transistor (BJT-BSIT) compound device in the low current operation. It also proposes a best thermal compensating factor to the compound device that indicates the relationship between the thermal variation rate of current gain and device structure. This is important for the design of compound device to be optimized. Finally, the analytical model is found to be in good agreement with numerical simulation and experimental results. The test results demonstrate that thermal variation rate of current gain is below 10% in 25℃C-85℃ and 20% in -55℃-25℃.

  13. Modeling quantization effects in field effect transistors

    International Nuclear Information System (INIS)

    Numerical simulation in the field of semiconductor device development advanced to a valuable, cost-effective and flexible facility. The most widely used simulators are based on classical models, as they need to satisfy time and memory constraints. To improve the performance of field effect transistors such as MOSFETs and HEMTs these devices are continuously scaled down in their dimensions. Consequently the characteristics of such devices are getting more and more determined by quantum mechanical effects arising from strong transversal fields in the channel. In this work an approach based on a two-dimensional electron gas is used to describe the confinement of the carriers. Quantization is considered in one direction only. For the derivation of a one-dimensional Schroedinger equation in the effective mass framework a non-parabolic correction for the energy dispersion due to Kane is included. For each subband a non-parabolic dispersion relation characterized by subband masses and subband non-parabolicity coefficients is introduced and the parameters are calculated via perturbation theory. The method described in this work has been implemented in a software tool that performs a self-consistent solution of Schroedinger- and Poisson-equation for a one-dimensional cut through a MOS structure or heterostructure. The calculation of the carrier densities is performed assuming Fermi-Dirac statistics. In the case of a MOS structure a metal or a polysilicon gate is considered and an arbitrary gate bulk voltage can be applied. This allows investigating quantum mechanical effects in capacity calculations, to compare the simulated data with measured CV curves and to evaluate the results obtained with a quantum mechanical correction for the classical electron density. The behavior of the defined subband parameters is compared to the value of the mass and the non-parabolicity coefficient from the model due to Kane. Finally the presented characterization of the subbands is applied

  14. Semiconductor data book characteristics of approx. 10,000 transistors, FETs, UJTs, diodes, rectifiers, optical semiconductors, triacs and SCRs

    CERN Document Server

    Ball, A M

    1981-01-01

    Semiconductor Data Book, 11th Edition presents tables for ratings and characteristics of transistors and multiple transistors; silicon field effect transistors; unijunction transistors; low power-, variable-, power rectifier-, silicon reference-, and light emitting diodes; photodetectors; triacs; thyristors; lead identification; and transistor comparable types. The book starts by providing an introduction and explanation of tables and manufacturers' codes and addresses. Professionals requiring such data about semiconductors will find the book useful.

  15. Electron properties of fluorinated single-layer graphene transistors

    OpenAIRE

    Withers, Freddie; Dubois, Marc; Savchenko, Alexander K.

    2010-01-01

    We have fabricated transistor structures using fluorinated single-layer graphene flakes and studied their electronic properties at different temperatures. Compared with pristine graphene, fluorinated graphene has very large and strongly temperature dependent resistance in the electro-neutrality region. We show that fluorination creates a mobility gap in graphene's spectrum where electron transport takes place via localised electron states.

  16. Graphene transistors with multifunctional polymer brushes for biosensing applications.

    Science.gov (United States)

    Hess, Lucas H; Lyuleeva, Alina; Blaschke, Benno M; Sachsenhauser, Matthias; Seifert, Max; Garrido, Jose A; Deubel, Frank

    2014-06-25

    Exhibiting a combination of exceptional structural and electronic properties, graphene has a great potential for the development of highly sensitive sensors. To date, many challenging chemical, biochemical, and biologic sensing tasks have been realized based on graphene. However, many of these sensors are rather unspecific. To overcome this problem, for instance, the sensor surface can be modified with analyte-specific transducers such as enzymes. One problem associated with the covalent attachment of such biomolecular systems is the introduction of crystal defects that have a deleterious impact on the electronic properties of the sensor. In this work, we present a versatile platform for biosensing applications based on polymer-modified CVD-grown graphene transistors. The functionalization method of graphene presented here allows one to integrate several functional groups within surface-bound polymer brushes without the introduction of additional defects. To demonstrate the potential of this polymer brush functionalization scaffold, we modified solution-gated graphene field-effect transistors with the enzyme acetylcholinesterase and a transducing group, allowing the detection of the neurotransmitter acetylcholine. Taking advantage of the transducing capability of graphene transistors and the versatility of polymer chemistry and enzyme biochemistry, this study presents a novel route for the fabrication of highly sensitive, multipurpose transistor sensors that can find application for a multitude of biologically relevant analytes. PMID:24866105

  17. Charge transport in disordered organic field-effect transistors

    NARCIS (Netherlands)

    Tanase, C; Blom, PWM; Meijer, EJ; de Leeuw, DM; Jabbour, GE; Carter, SA; Kido, J; Lee, ST; Sariciftci, NS

    2002-01-01

    The transport properties of poly(2,5-thienylene vinylene) (PTV) field-effect transistors (FET) have been investigated as a function of temperature under controlled atmosphere. In a disordered semiconductor as PTV the charge carrier mobility, dominated by hopping between localized states, is dependen

  18. Flexible carbon-based ohmic contacts for organic transistors

    Science.gov (United States)

    Brandon, Erik (Inventor)

    2007-01-01

    The present invention relates to a system and method of organic thin-film transistors (OTFTs). More specifically, the present invention relates to employing a flexible, conductive particle-polymer composite material for ohmic contacts (i.e. drain and source).

  19. Performance and processability of organic field effect transistors

    OpenAIRE

    Alt, Milan

    2015-01-01

    The present work addresses challenges with the performance and processability of organic semiconductors for their application in organic field-effect transistors (OFET). The results that are presented in this thesis show that combining advances in chemical material design and interface tailoring with advances in deposition and processing techniques, in order to unfold the potential of organic electronics, is a matter of engineering.

  20. A high current, high speed pulser using avalanche transistors

    International Nuclear Information System (INIS)

    A high current, high speed pulser for the beam pulsing of a linear accelerator is described. It uses seven avalanche transistors in cascade. Design of a trigger circuit to obtain fast rise time is discussed. The characteristics of the pulser are : (a) Rise time = 0.9 ns (FWHM) and (d) Life time asymptotically equals 2000 -- 3000 hr (at 50 Hz). (author)

  1. Phonon diodes and transistors from magneto-acoustics

    OpenAIRE

    Sklan, Sophia R.; Grossman, Jeffrey C.

    2014-01-01

    By sculpting the magnetic field applied to magneto-acoustic materials, phonons can be used for information processing. Using a combination of analytic and numerical techniques, we demonstrate designs for diodes (isolators) and transistors that are independent of their conventional, electronic formulation. We analyze the experimental feasibility of these systems, including the sensitivity of the circuits to likely systematic and random errors.

  2. Current-Induced Transistor Sensorics with Electrogenic Cells

    Directory of Open Access Journals (Sweden)

    Peter Fromherz

    2016-04-01

    Full Text Available The concepts of transistor recording of electroactive cells are considered, when the response is determined by a current-induced voltage in the electrolyte due to cellular activity. The relationship to traditional transistor recording, with an interface-induced response due to interactions with the open gate oxide, is addressed. For the geometry of a cell-substrate junction, the theory of a planar core-coat conductor is described with a one-compartment approximation. The fast electrical relaxation of the junction and the slow change of ion concentrations are pointed out. On that basis, various recording situations are considered and documented by experiments. For voltage-gated ion channels under voltage clamp, the effects of a changing extracellular ion concentration and the enhancement/depletion of ion conductances in the adherent membrane are addressed. Inhomogeneous ion conductances are crucial for transistor recording of neuronal action potentials. For a propagating action potential, the effects of an axon-substrate junction and the surrounding volume conductor are distinguished. Finally, a receptor-transistor-sensor is described, where the inhomogeneity of a ligand–activated ion conductance is achieved by diffusion of the agonist and inactivation of the conductance. Problems with regard to a development of reliable biosensors are mentioned.

  3. Carbon nanotube thin film transistors based on aerosol methods

    International Nuclear Information System (INIS)

    We demonstrate a fabrication method for high-performance field-effect transistors (FETs) based on dry-processed random single-walled carbon nanotube networks (CNTNs) deposited at room temperature. This method is an advantageous alternative to solution-processed and direct CVD grown CNTN FETs, which allows using various substrate materials, including heat-intolerant plastic substrates, and enables an efficient, density-controlled, scalable deposition of as-produced single-walled CNTNs on the substrate directly from the aerosol (floating catalyst) synthesis reactor. Two types of thin film transistor (TFT) structures were fabricated to evaluate the FET performance of dry-processed CNTNs: bottom-gate transistors on Si/SiO2 substrates and top-gate transistors on polymer substrates. Devices exhibited on/off ratios up to 105 and field-effect mobilities up to 4 cm2 V-1 s-1. The suppression of hysteresis in the bottom-gate device transfer characteristics by means of thermal treatment in vacuum and passivation by an atomic layer deposited Al2O3 film was investigated. A 32 nm thick Al2O3 layer was found to be able to eliminate the hysteresis.

  4. Conductance switching in organic ferroelectric field-effect transistors

    NARCIS (Netherlands)

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

    2011-01-01

    Staggered bottom-contact top-gate organic ferroelectric field-effect transistors are fabricated with poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) as ferroelectric gate and poly[bis(4-phenyl)(2,4,6- trimethylphenyl)amine] as semiconductor. Polarization reversal of the ferroelectric gate

  5. Transistor-like behavior of transition metal complexes

    DEFF Research Database (Denmark)

    Albrecht, Tim; Guckian, A; Ulstrup, Jens;

    2005-01-01

    scanning tunneling microscope (in situ STM). This configuration resembles a single-molecule transistor, where the reference electrode corresponds to the gate electrode. It operates at room temperature in a condensed matter (here aqueous) environment. Amplification on-off ratios up to 50 are found when the...

  6. Effects of overheating in a single-electron transistor

    DEFF Research Database (Denmark)

    Korotkov, A. N.; Samuelsen, Mogens Rugholm; Vasenko, S. A.

    1994-01-01

    Heating of a single-electron transistor (SET) caused by the current flowing through it is considered. The current and the temperature increase should be calculated self-consistently taking into account various paths of the heat drain. Even if there is no heat drain from the central electrode of the...

  7. Nanoscaled biological gated field effect transistors for cytogenetic analysis

    DEFF Research Database (Denmark)

    Kwasny, Dorota; Dimaki, Maria; Andersen, Karsten Brandt;

    2014-01-01

    Cytogenetic analysis is the study of chromosome structure and function, and is often used in cancer diagnosis, as many chromosome abnormalities are linked to the onset of cancer. A novel label free detection method for chromosomal translocation analysis using nanoscaled field effect transistors...

  8. Organic transistors in optical displays and microelectronic applications

    NARCIS (Netherlands)

    Gelinck, G.H.; Heremans, P.; Nomoto, K.; Anthopoulos, T.D.

    2010-01-01

    Organic thin-film transistors (OTFTs) offer unprecedented opportunities for implementation in a broad range of technological applications spanning from large-volume microelectronics and optical displays to chemical and biological sensors. In this Progress Report, we review the application of organic

  9. Metal-nanoparticle single-electron transistors fabricated using electromigration

    DEFF Research Database (Denmark)

    Bolotin, K I; Kuemmeth, Ferdinand; Pasupathy, A N;

    2004-01-01

    We have fabricated single-electron transistors from individual metal nanoparticles using a geometry that provides improved coupling between the particle and the gate electrode. This is accomplished by incorporating a nanoparticle into a gap created between two electrodes using electromigration, all...

  10. Multicolored Nanofiber Based Organic Light-Emitting Transistor

    DEFF Research Database (Denmark)

    With Jensen, Per Baunegaard; Kjelstrup-Hansen, Jakob; Tavares, Luciana;

    driven device by combining nanofibers made from two different molecules, parahexaphenylene (p6P) and 5,5´-Di-4-biphenyl-2,2´-bithiophene (PPTTPP), which emits blue and green light, respectively. The organic nanofibers are implemented on a bottom gate/bottom contact field-effect transistor platform using...

  11. Ultrathin regioregular poly(3-hexyl thiophene) field-effect transistors

    DEFF Research Database (Denmark)

    Sandberg, H.G.O.; Frey, G.L.; Shkunov, M.N.;

    2002-01-01

    Ultrathin films of regioregular poly(3-hexyl thiophene) (RR-P3HT) were deposited through a dip-coating technique and utilized as the semiconducting film in field-effect transistors (FETs). Proper selection of the substrate and solution concentration enabled the growth of a monolayer-thick RR-P3HT...

  12. π-Conjugated Organic Semiconductors for Field-Effect Transistors

    Institute of Scientific and Technical Information of China (English)

    LIU Yun-qi

    2005-01-01

    @@ 1Results and Discussion Organic semiconductors employed as active layers in field-effect transistors (FETs) are of great current interest because such FETs can potentially be fabricated at low cost, over large areas, and on flexible substrates. Such facile fabrication approaches offer a significant advantage over silicon technology in numerous applications.

  13. Reconfigurable Threshold Logic Element with SET and MOS Transistors

    Institute of Scientific and Technical Information of China (English)

    WEI Rong-Shan; CHEN Jin-Feng; CHEN Shou-Chang; HE Ming-Hua

    2012-01-01

    A novel reconfigurable threshold logic element (TLE) using single-electron transistors (SETs) and metal-oxide semiconductor (MOS) transistors is proposed.The proposed TLE is highly reconfigurable,which can perform all two-variable logic functions directly or indirectly,including OR,NOR,AND,NAND,XOR and XNOR.The reconfiguration of the TLE is realized by simply configuring the input bits without changing the device parameters.The design methodology can also be applied in the design of a multi-variable TLE.The reconfigurable TLE demonstrates good performance at room temperature with a compact structure and ultralow power dissipation.The reconfigurable TLE can be useful in high-density high-performance reconfigurable systems and artificial neural networks.%A novel reconfigurable threshold logic element (TLE) using single-electron transistors (SETs) and metal-oxide-semiconductor (MOS) transistors is proposed. The proposed TLE is highly reconfigurable, which can perform all two-variable logic functions directly or indirectly, including OR, NOR, AND, NAND, XOR and XNOR. The reconfiguration of the TLE is realized by simply configuring the input bits without changing the device parameters. The design methodology can also be applied in the design of a multi-variable TLE. The reconfigurable TLE demonstrates good performance at room temperature with a compact structure and ultralow power dissipation. The reconfigurable TLE can be useful in high-density high-performance reconfigurable systems and artificial neural networks.

  14. Experiments with Charge Indicator Based on Bipolar Transistors

    Science.gov (United States)

    Dvorak, Leos; Planinsic, Gorazd

    2012-01-01

    A simple charge indicator with bipolar transistors described recently enables us to perform a number of experiments suitable for high-school physics. Several such experiments are presented and discussed in this paper as well as some features of the indicator important for its use in schools, namely its sensitivity and robustness, i.e. the…

  15. Current-Induced Transistor Sensorics with Electrogenic Cells.

    Science.gov (United States)

    Fromherz, Peter

    2016-01-01

    The concepts of transistor recording of electroactive cells are considered, when the response is determined by a current-induced voltage in the electrolyte due to cellular activity. The relationship to traditional transistor recording, with an interface-induced response due to interactions with the open gate oxide, is addressed. For the geometry of a cell-substrate junction, the theory of a planar core-coat conductor is described with a one-compartment approximation. The fast electrical relaxation of the junction and the slow change of ion concentrations are pointed out. On that basis, various recording situations are considered and documented by experiments. For voltage-gated ion channels under voltage clamp, the effects of a changing extracellular ion concentration and the enhancement/depletion of ion conductances in the adherent membrane are addressed. Inhomogeneous ion conductances are crucial for transistor recording of neuronal action potentials. For a propagating action potential, the effects of an axon-substrate junction and the surrounding volume conductor are distinguished. Finally, a receptor-transistor-sensor is described, where the inhomogeneity of a ligand-activated ion conductance is achieved by diffusion of the agonist and inactivation of the conductance. Problems with regard to a development of reliable biosensors are mentioned. PMID:27120627

  16. Selected Transistor Material for the Information-Seeking Adult.

    Science.gov (United States)

    Ringold, Dorman R.

    This study was undertaken to identify and organize meaningful and useful basic materials on transistor principles and applications, and to explore some of the elements required for adult teaching. It was limited to the apparent needs of information-seeking adults in greater Los Angeles who desired occupational skills. A literature review…

  17. Durable chemical sensors based on field-effect transistors

    NARCIS (Netherlands)

    Reinhoudt, D.N.

    1995-01-01

    The design of durable chemical sensors based on field-effect transistors (FETs) is described. After modification of an ion-sensitive FET (ISFET) with a polysiloxane membrane matrix, it is possible to attach all electroactive components covalently. Preliminary results of measurements with a sodium-se

  18. Multiple facets of tightly coupled transducer-transistor structures

    Science.gov (United States)

    Heidari, Hadi; Dahiya, Ravinder

    2015-12-01

    The ever increasing demand for data processing requires different paradigms for electronics. Excellent performance capabilities such as low power and high speed in electronics can be attained through several factors including using functional materials, which sometimes acquire superior electronic properties. The transduction-based transistor switching mechanism is one such possibility, which exploits the change in electrical properties of the transducer as a function of a mechanically induced deformation. Originally developed for deformation sensors, the technique is now moving to the centre stage of the electronic industry as the basis for new transistor concepts to circumvent the gate voltage bottleneck in transistor miniaturization. In issue 37 of Nanotechnology, Chang et al show the piezoelectronic transistor (PET), which uses a fast, low-power mechanical transduction mechanism to propagate an input gate voltage signal into an output resistance modulation. The findings by Chang et al will spur further research into piezoelectric scaling, and the PET fabrication techniques needed to advance this type of device in the future.

  19. Threshold voltage shift of mos transistors by ion implantation

    International Nuclear Information System (INIS)

    The simple theory of the use of ion implantation of mos transistors to shift threshold voltage is outlined. Discrepancies between theory and practice are discussed. A modified model is proposed in which all implanted ions contribute to the threshold voltage shift irrespective of energy levels. (U.K.)

  20. Relating hysteresis and electrochemistry in graphene field effect transistors

    NARCIS (Netherlands)

    Veligura, Alina; Zomer, Paul J.; Vera-Marun, Ivan J.; Jozsa, Csaba; Gordiichuk, Pavlo I.; van Wees, Bart J.

    2011-01-01

    Hysteresis and commonly observed p-doping of graphene based field effect transistors (FETs) have been discussed in reports over the last few years. However, the interpretation of experimental works differs; and the mechanism behind the appearance of the hysteresis and the role of charge transfer bet

  1. Single event burnout sensitivity of embedded field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Koga, R.; Crain, S.H.; Crawford, K.B.; Yu, P.; Gordon, M.J.

    1999-12-01

    Observations of single event burnout (SEB) in embedded field effect transistors are reported. Both SEB and other single event effects are presented for several pulse width modulation and high frequency devices. The microscope has been employed to locate and to investigate the damaged areas. A model of the damage mechanism based on the results so obtained is described.

  2. Conducted EMI in Inverters with SiC Transistors

    NARCIS (Netherlands)

    Gong, X.

    2013-01-01

    Conducted EMI in Inverters with SiC Transistors Electromagnetic Interference (EMI) is the main side effect accompanied with the fast voltage and current switching transients in power electronics applications. Compliance of the Electromagnetic Compatibility (EMC) standard is prescribed for any power

  3. Bipolar Transistors Can Detect Charge in Electrostatic Experiments

    Science.gov (United States)

    Dvorak, L.

    2012-01-01

    A simple charge indicator with bipolar transistors is described that can be used in various electrostatic experiments. Its behaviour enables us to elucidate links between 'static electricity' and electric currents. In addition it allows us to relate the sign of static charges to the sign of the terminals of an ordinary battery. (Contains 7 figures…

  4. Fabrication and characterization of heterojunction transistors

    Science.gov (United States)

    Lo, Chien-Fong

    2011-12-01

    Submircon emitter finger high-speed double heterojunction InAlAs/InGaAsSb/InGaAs bipolar transistors (DHBTs) and a variety of nitride high electron mobility transistors (HEMTs) including AlGaN/GaN, InAlN/GaN, and AlN/GaN were fabricated and characterized. DHBT structures were grown by solid source molecular beam epitaxy (SSMBE) on Fe-doped semiinsulating InP substrates and nitride HEMTs were grown with a metal organic chemical vapor deposition (MOCVD) system on sapphire or SiC substrates. AlN/GaN HEMTs were grown with a RF-VMBE on sapphire substrates. Ultra low base contact resistance of 3.7 x 10-7 ohm-cm2 after 1 min 250¢XC thermal treatment on noval InGaAsSb base of DHBTs was achieved and a long-term thermal stability of base metallization was studied. Regarding small scale DHBT fabrication, tri-layer system was introduced to improve the resolution for submicron emitter patterning and help to pile up a thicker emitter metal stack; guard-ring technique was applied around the emitter periphery in order to preserve the current gain at small emitter dimensions. Ultra low turn-on voltage and high current gain can be realized with InGaAsSb-base DHBTs as compared to the conventional InGaAs-base DHBTs. A peak current gain cutoff frequency (fT) of 268 GHz and power gain cutoff frequency (fmax) of 485 GHz were achieved. GaN-based HEMTs herein were fabricated with gate lengths from 400 nm to 1im, and were deposited Ti/Al/Ni/Au as their Ohmic contact metallization. Effects of the Ohmic contact annealing for lattice-matched InAlN/GaN HEMTs with and without a thin GaN cap layer were exhibited and their optimal annealing temperature were obtained. A maximum drain current of 1.3 A/mm and an extrinsic transconductance of 366 mS/mm were demonstrated for InAlN/GaN HEMTs with the shortest gate length. A unity-gain cutoff frequency (fT) of 69 GHz and a maximum frequency of oscillation (fmax) of 80 GHz for InAlN/GaN HEMTs were extracted from measured scattering parameters

  5. Silicon Carbide Technologies for High Temperature Motor Drives

    OpenAIRE

    Snefjellå, Øyvind Holm

    2011-01-01

    Many applications benefit from using converters which can operate at high temperatures among them; down-hole drilling, hybrid vehicles and space craft. The theoretical performance of transistors made of Silicon Carbide (SiC) is investigated in this work. It is shown that their properties at high temperatures are superior compared to Silicon (Si) devices. Two half-bridge converters, using SiC normally-off Junction Field Effect Transistors (JFET) and SiC Bipolar Junction Transistors (BJT), are ...

  6. Atmospheric pressure chemical vapour deposition of vanadium arsenide thin films via the reaction of VCl4 or VOCl3 with tBuAsH2

    International Nuclear Information System (INIS)

    Thin films of vanadium arsenide were deposited via the dual-source atmospheric pressure chemical vapour deposition reactions of VCl4 or VOCl3 with tBuAsH2. Using the vanadium precursor VCl4, films were deposited at substrate temperatures of 550–600 °C, which were black-gold in appearance and were found to be metal-rich with high levels of chlorine incorporation. The use of VOCl3 as the vanadium source resulted in films being deposited between 450 and 600 °C and, unlike when using VCl4, were silver in appearance. The films deposited using VOCl3 demonstrated vanadium to arsenic ratios close to 1:1, and negligible chlorine incorporation. Films deposited using either vanadium precursor were identified as VAs using powder X-ray diffraction and possessed borderline metallic/semiconductor resistivities. - Highlights: • Formation of VAs films via atmospheric pressure chemical vapour deposition. • Films formed using VCl4 or VOCl3 and tBuAsH2. • Powder X-ray diffraction showed that crystalline VAs films were deposited. • Films from VOCl3 had a V:As ratio close to 1 with negligible Cl incorporation. • Films were silver and possessed borderline metallic/semiconductor resistivities

  7. A novel wide range, real-time neutron fluence monitor based on commercial off the shelf gallium arsenide light emitting diodes

    International Nuclear Information System (INIS)

    Displacement damage produced by high-energy neutrons in gallium arsenide (GaAs) light emitting diodes (LED) results in the reduction of light output. Based on this principle we have developed a simple, cost effective, neutron detector using commercial off the shelf (COTS) GaAs-LED for the assessment of neutron fluence and KERMA at critical locations in the vicinity of the 230 MeV proton therapy cyclotron operated by Westdeutsches Protonentherapiezentrum Essen (WPE). The LED detector response (mV) was found to be linear within the neutron fluence range of 3.0x108-1.0x1011 neutron cm-2. The response of the LED detector was proportional to neutron induced displacement damage in LED; hence, by using the differential KERMA coefficient of neutrons in GaAs, we have rescaled the calibration curve for two mono-energetic sources, i.e. 1 MeV neutrons and 14 MeV neutrons generated by D+T fusion reaction. In this paper we present the principle of the real-time GaAs-LED based neutron fluence monitor as mentioned above. The device was calibrated using fast neutrons produced by bombarding a thick beryllium target with 14 MeV deuterons from a TCC CV 28 medical cyclotron of the Strahlenklinik University Hospital Essen.

  8. Total dose effects on the matching properties of deep submicron MOS transistors

    International Nuclear Information System (INIS)

    Based on 0.18 μm MOS transistors, for the first time, the total dose effects on the matching properties of deep submicron MOS transistors are studied. The experimental results show that the total dose radiation magnifies the mismatch among identically designed MOS transistors. In our experiments, as the radiation total dose rises to 200 krad, the threshold voltage and drain current mismatch percentages of NMOS transistors increase from 0.55% and 1.4% before radiation to 17.4% and 13.5% after radiation, respectively. PMOS transistors seem to be resistant to radiation damage. For all the range of radiation total dose, the threshold voltage and drain current mismatch percentages of PMOS transistors keep under 0.5% and 2.72%, respectively. (semiconductor devices)

  9. Polarity control in WSe2 double-gate transistors

    Science.gov (United States)

    Resta, Giovanni V.; Sutar, Surajit; Balaji, Yashwanth; Lin, Dennis; Raghavan, Praveen; Radu, Iuliana; Catthoor, Francky; Thean, Aaron; Gaillardon, Pierre-Emmanuel; de Micheli, Giovanni

    2016-01-01

    As scaling of conventional silicon-based electronics is reaching its ultimate limit, considerable effort has been devoted to find new materials and new device concepts that could ultimately outperform standard silicon transistors. In this perspective two-dimensional transition metal dichalcogenides, such as MoS2 and WSe2, have recently attracted considerable interest thanks to their electrical properties. Here, we report the first experimental demonstration of a doping-free, polarity-controllable device fabricated on few-layer WSe2. We show how modulation of the Schottky barriers at drain and source by a separate gate, named program gate, can enable the selection of the carriers injected in the channel, and achieved controllable polarity behaviour with ON/OFF current ratios >106 for both electrons and holes conduction. Polarity-controlled WSe2 transistors enable the design of compact logic gates, leading to higher computational densities in 2D-flatronics. PMID:27390014

  10. A Fast Dynamic 64-bit Comparator with Small Transistor Count

    Directory of Open Access Journals (Sweden)

    Chua-Chin Wang

    2002-01-01

    Full Text Available In this paper, we propose a 64-bit fast dynamic CMOS comparator with small transistor count. Major features of the proposed comparator are the rearrangement and re-ordering of transistors in the evaluation block of a dynamic cell, and the insertion of a weak n feedback inverter, which helps the pull-down operation to ground. The simulation results given by pre-layout tools, e.g. HSPICE, and post-layout tools, e.g. TimeMill, reveal that the delay is around 2.5 ns while the operating clock rate reaches 100 MHz. A physical chip is fabricated to verify the correctness of our design by using UMC (United Microelectronics Company 0.5 μm (2P2M technology.

  11. Capacitance Variation of Electrolyte-Gated Bilayer Graphene Based Transistors

    Directory of Open Access Journals (Sweden)

    Hediyeh Karimi

    2013-01-01

    Full Text Available Quantum capacitance of electrolyte-gated bilayer graphene field-effect transistors is investigated in this paper. Bilayer graphene has received huge attention due to the fact that an energy gap could be opened by chemical doping or by applying external perpendicular electric field. So, this extraordinary property can be exploited to use bilayer graphene as a channel in electrolyte-gated field-effect transistors. The quantum capacitance of bi-layer graphene with an equivalent circuit is presented, and also based on the analytical model a numerical solution is reported. We begin by modeling the DOS, followed by carrier concentration as a function V in degenerate and nondegenerate regimes. To further confirm this viewpoint, the presented analytical model is compared with experimental data, and acceptable agreement is reported.

  12. Suppression of tunneling leakage current in junctionless nanowire transistors

    International Nuclear Information System (INIS)

    In this paper, the characteristics of tunneling leakage current for the dual-material gate junctionless nanowire transistor (DMG-JNT) are investigated by three-dimensional numerical simulations and compared with conventional junctionless nanowire transistor (JNT). The suppression of the tunneling leakage current on the JNT by introducing an energy band step with the DMG structure is verified and presented for the first time. The effects of channel length on the DMG-JNT and the JNT are also studied. Results showed that the tunneling leakage current of the DMG-JNT is two orders smaller than that of the JNT, and further, the DMG-JNT exhibits superior scaling capability. Two key design parameters of the DMG-JNT, control gate ratio (Ra) and work function difference (δW), have been optimized and the optimal ranges of Ra and δW are pointed out. (paper)

  13. A Single-Transistor Active Pixel CMOS Image Sensor Architecture

    International Nuclear Information System (INIS)

    A single-transistor CMOS active pixel image sensor (1 T CMOS APS) architecture is proposed. By switching the photosensing pinned diode, resetting and selecting can be achieved by diode pull-up and capacitive coupling pull-down of the source follower. Thus, the reset and selected transistors can be removed. In addition, the reset and selected signal lines can be shared to reduce the metal signal line, leading to a very high fill factor. The pixel design and operation principles are discussed in detail. The functionality of the proposed 1T CMOS APS architecture has been experimentally verified using a fabricated chip in a standard 0.35 μm CMOS AMIS technology

  14. Orientation selectivity in a multi-gated organic electrochemical transistor

    Science.gov (United States)

    Gkoupidenis, Paschalis; Koutsouras, Dimitrios A.; Lonjaret, Thomas; Fairfield, Jessamyn A.; Malliaras, George G.

    2016-06-01

    Neuromorphic devices offer promising computational paradigms that transcend the limitations of conventional technologies. A prominent example, inspired by the workings of the brain, is spatiotemporal information processing. Here we demonstrate orientation selectivity, a spatiotemporal processing function of the visual cortex, using a poly(3,4ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS) organic electrochemical transistor with multiple gates. Spatially distributed inputs on a gate electrode array are found to correlate with the output of the transistor, leading to the ability to discriminate between different stimuli orientations. The demonstration of spatiotemporal processing in an organic electronic device paves the way for neuromorphic devices with new form factors and a facile interface with biology.

  15. Organic Light-Emitting Diodes Driven by Organic Transistors

    Institute of Scientific and Technical Information of China (English)

    胡远川; 董桂芳; 王立铎; 梁琰; 邱勇

    2004-01-01

    Organic thin-film field-effect transistors (OTFTs) with pentacene as the semiconductor have been fabricated for driving an organic light-emitting diode (OLED). The driving circuit includes two OTFTs and one storage capacitor. The field-effect mobility of the transistors in the driving circuit is more than 0.3 cm2/Vs, and the on/off ratio is larger than 104. The light-emission area of the OLED is 0. 04mm2 and the brightness is larger than 400cd/m2 when the selected line voltage, data line voltage and drive voltage all are -40 V. The responding characteristics and holding characteristics are also researched when the selected line voltage and the date line voltage are changed.

  16. Vertical Organic Field-Effect Transistors for Integrated Optoelectronic Applications.

    Science.gov (United States)

    Yu, Hyeonggeun; Dong, Zhipeng; Guo, Jing; Kim, Doyoung; So, Franky

    2016-04-27

    Direct integration of a vertical organic field-effect transistor (VOFET) and an optoelectronic device offers a single stacked, low power optoelectronic VOFET with high aperture ratios. However, a functional optoelectronic VOFET could not be realized because of the difficulty in fabricating transparent source and gate electrodes. Here, we report a VOFET with an on/off ratio up to 10(5) as well as output current saturation by fabricating a transparent gate capacitor consisting of a perforated indium tin oxide (ITO) source electrode, HfO2 gate dielectric, and ITO gate electrode. Effects of the pore size and the pore depth within the porous ITO electrodes on the on/off characteristic of a VOFET are systematically explained in this work. By combining a phosphorescent organic light-emitting diode with an optimized VOFET structure, a vertical organic light-emitting transistor with a luminance on/off ratio of 10(4) can be fabricated. PMID:27082815

  17. Measurement of ionizing radiation using carbon nanotube field effect transistor

    International Nuclear Information System (INIS)

    Single-walled carbon nanotubes (SWNTs) are a new class of highly promising nanomaterials for future nano-electronics. Here, we present an initial investigation of the feasibility of using SWNT field effect transistors (SWNT-FETs) formed on silicon-oxide substrates and suspended FETs for radiation dosimetry applications. Electrical measurements and atomic force microscopy (AFM) revealed the intactness of SWNT-FET devices after exposure to over 1 Gy of 6 MV therapeutic x-rays. The sensitivity of SWNT-FET devices to x-ray irradiation is elucidated by real-time dose monitoring experiments and accumulated dose reading based on threshold voltage shift. SWNT-FET devices exhibit sensitivities to x-rays that are at least comparable to or orders of magnitude higher than commercial MOSFET (metal-oxide semiconductor field effect transistor) dosimeters and could find applications as miniature dosimeters for microbeam profiling and implantation. (note)

  18. Modeling and Simulation of Photoelectronic Lambda Bipolar Transistor

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Based on the region model of lambda bipolar transistor (LBT), a dividing region theory model of PLBT is set up,simulated and verified. Firstly, the principal operations of different kinds of photoelectronic lambda bipolar transistor (PLBT) are characterized by a simple circuit model.Through mathematical analysis of the equivalent circuit, the typical characteristics curve is divided into positive resistance, peak, negative resistance and cutoff regions. Secondly, by analyzing and simulating this model, the ratio of MOSFET width to channel length, threshold voltage and common emitter gain are discovered as the main structure parameters that determine the characteristic curves of PLBT. And peak region width, peak current value, negative resistance value and valley voltage value of PLBT can be changed conveniently according to the actual demands by modifying these parameters. Finally comparisons of the characteristics of the fabricated devices and the simulation results are made, which show that the analytical results are in agreement with the observed devices characteristics.

  19. Carbon nanotube transistors with graphene oxide films as gate dielectrics

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Carbon nanomaterials,including the one-dimensional(1-D) carbon nanotube(CNT) and two-dimensional(2-D) graphene,are heralded as ideal candidates for next generation nanoelectronics.An essential component for the development of advanced nanoelectronics devices is processing-compatible oxide.Here,in analogy to the widespread use of silicon dioxide(SiO2) in silicon microelectronic industry,we report the proof-of-principle use of graphite oxide(GO) as a gate dielectrics for CNT field-effect transistor(FET) via a fast and simple solution-based processing in the ambient condition.The exceptional transistor characteristics,including low operation voltage(2 V),high carrier mobility(950 cm2/V-1 s-1),and the negligible gate hysteresis,suggest a potential route to the future all-carbon nanoelectronics.

  20. Laser direct synthesis of silicon nanowire field effect transistors

    International Nuclear Information System (INIS)

    We demonstrate a single-step, laser-based technique to fabricate silicon nanowire field effect transistors. Boron-doped silicon nanowires are synthesized using a laser-direct-write chemical vapor deposition process, which can produce nanowires as small as 60 nm, far below the diffraction limit of the laser wavelength of 395 nm. In addition, the method has the advantages of in situ doping, catalyst-free growth, and precise control of nanowire position, orientation, and length. Silicon nanowires are directly fabricated on an insulating surface and ready for subsequent device fabrication without the need for transfer and alignment, thus greatly simplifying device fabrication processes. Schottky barrier nanowire field effect transistors with a back-gate configuration are fabricated from the laser-direct-written Si nanowires and electrically characterized. (paper)

  1. Polarity control in WSe2 double-gate transistors.

    Science.gov (United States)

    Resta, Giovanni V; Sutar, Surajit; Balaji, Yashwanth; Lin, Dennis; Raghavan, Praveen; Radu, Iuliana; Catthoor, Francky; Thean, Aaron; Gaillardon, Pierre-Emmanuel; de Micheli, Giovanni

    2016-01-01

    As scaling of conventional silicon-based electronics is reaching its ultimate limit, considerable effort has been devoted to find new materials and new device concepts that could ultimately outperform standard silicon transistors. In this perspective two-dimensional transition metal dichalcogenides, such as MoS2 and WSe2, have recently attracted considerable interest thanks to their electrical properties. Here, we report the first experimental demonstration of a doping-free, polarity-controllable device fabricated on few-layer WSe2. We show how modulation of the Schottky barriers at drain and source by a separate gate, named program gate, can enable the selection of the carriers injected in the channel, and achieved controllable polarity behaviour with ON/OFF current ratios >10(6) for both electrons and holes conduction. Polarity-controlled WSe2 transistors enable the design of compact logic gates, leading to higher computational densities in 2D-flatronics. PMID:27390014

  2. Understanding noise suppression in heterojunction field-effect transistors

    International Nuclear Information System (INIS)

    Full text: The enhanced transport properties displayed by quantum-well-confined, two-dimensional, electron systems underpin the success of heterojunction, field-effect transistors. At cryogenic temperatures, these devices exhibit impressive mobilities and, as a result, high signal gain and low noise. Conventional wisdom has it that the same favourable conditions also hold for normal room-temperature operation. In that case, however, high mobilities are precluded by abundant electron-phonon scattering. Our recent study of nonequilibrium current noise shows that quantum confinement, not high mobility, is the principal source of noise in these devices; this opens up new and exciting opportunities in low-noise transistor design. As trends in millimetre-wave technology push frequencies beyond 100 GHz, it is essential to develop a genuine understanding of noise processes in heterojunction devices

  3. Fullerene thin-film transistors fabricated on polymeric gate dielectric

    Energy Technology Data Exchange (ETDEWEB)

    Puigdollers, J. [Micro and Nano Technology Group (MNT), Dept. Enginyeria Electronica, Universitat Politecnica Catalunya, C/ Jordi Girona 1-3, Modul C4, 08034-Barcelona (Spain)], E-mail: jpuigd@eel.upc.edu; Voz, C. [Micro and Nano Technology Group (MNT), Dept. Enginyeria Electronica, Universitat Politecnica Catalunya, C/ Jordi Girona 1-3, Modul C4, 08034-Barcelona (Spain); Cheylan, S. [ICFO - Mediterranean Technology Park, Avda del Canal Olimpic s/n, 08860-Castelldefels (Spain); Orpella, A.; Vetter, M.; Alcubilla, R. [Micro and Nano Technology Group (MNT), Dept. Enginyeria Electronica, Universitat Politecnica Catalunya, C/ Jordi Girona 1-3, Modul C4, 08034-Barcelona (Spain)

    2007-07-16

    Thin-film transistors with fullerene as n-type organic semiconductor have been fabricated. A polymeric gate dielectric, polymethyl methacrylate, has been used as an alternative to usual inorganic dielectrics. No significant differences in the microstructure of fullerene thin-films grown on polymethyl methacrylate were observed. Devices with either gold or aluminium top electrodes have been fabricated. Although the lower work-function of aluminium compared to gold should favour electron injection, similar field-effect mobilities in the range of 10{sup -2} cm{sup 2} V{sup -1} s{sup -1} were achieved in both cases. Actually, the output characteristics indicate that organic thin-film transistors behave more linearly with gold than with aluminium electrodes. These results confirm that not only energy barriers determine carrier injection at metal/organic interfaces, but also chemical interactions.

  4. 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.

  5. Low-frequency noise in single electron tunneling transistor

    DEFF Research Database (Denmark)

    Tavkhelidze, A.N.; Mygind, Jesper

    1998-01-01

    The noise in current biased aluminium single electron tunneling (SET) transistors has been investigated in the frequency range of 5 mHz radiation and especially high energy...... photons emitted by the 4.2 K environment from reaching the sample, allows us to study a given background charge configuration for many hours below [approximate] 100 mK. The noise at relatively high frequencies originates from internal (presumably thermal equilibrium) charge fluctuations. For f >= 10 Hz......, we find the same input charge noise, typically QN = 5 × 10–4 e/Hz1/2 at 10 Hz, with and without the HF shielding. At lower frequencies, the noise is due to charge trapping, and the voltage noise pattern superimposed on the V(Vg) curve (voltage across transistor versus gate voltage) strongly depends...

  6. Carbon nanotube transistor optimization by chemical control of the nanotube-metal interface

    Science.gov (United States)

    Auvray, S.; Borghetti, J.; Goffman, M. F.; Filoramo, A.; Derycke, V.; Bourgoin, J. P.; Jost, O.

    2004-06-01

    Most carbon nanotube transistors work as Schottky barrier transistors. We show that chemical treatment of operational p-type nanotube transistors by trifluoro-acetic acid (TFA) leads to the drastic improvement of all the key device parameters. This effect is due to the highly polar nature of the TFA molecule which, once adsorbed at the metal-nanotube interface, lowers the Schottky barrier for the holes and thus favors their injection.

  7. Performance Analysis of Silicon and Germanium Nanowire Transistor using Crystal Orientation and Oxide Thickness

    OpenAIRE

    P.Theres Mary; N.B. BALAMURUGAN

    2014-01-01

    Nanowire Transistors have attracted attention due to the probable high performance and excellent controllability of device current. In this paper, we investigate the performance analysis of nanowire transistors made of silicon and germanium materials. The nanowire transistor has a 3D distribution of electron density and electrostatic potential, therefore self-consistent 3D simulations are used. Nanowire (tool) is 3D Poisson self-consistent simulator which can study the 3D transport in nanowir...

  8. Micro-irradiation experiments in MOS transistors using synchrotron radiation

    International Nuclear Information System (INIS)

    Spatially-resolved total-dose degradation has been performed in MOS transistors by focusing x-ray synchrotron radiation on the gate electrode with micrometer resolution. The influence of the resulting permanent degradation on device electrical properties has been analyzed using current-voltage and charge pumping measurements, in concert with optical characterization (hot-carrier luminescence) and one-dimensional device simulation. (authors)

  9. Induced base transistor fabricated by molecular beam epitaxy

    Science.gov (United States)

    Chang, C.-Y.; Liu, W. C.; Jame, M. S.; Wang, Y. H.; Luryi, S.

    1986-09-01

    A novel three-terminal hot-electron device, the induced base transistor (IBT), has been fabricated by molecular beam epitaxy. Two-dimensional electron gas induced by the applied collector field in an undoped GaAs quantum well is used as the base of the IBT. The common-base current gain alpha has been achieved as high as 0.96 under a collector bias of 2.5 V and an emitter current of 3 mA.

  10. Transistor-based metamaterials with dynamically tunable nonlinear susceptibility

    Science.gov (United States)

    Barrett, John P.; Katko, Alexander R.; Cummer, Steven A.

    2016-08-01

    We present the design, analysis, and experimental demonstration of an electromagnetic metamaterial with a dynamically tunable effective nonlinear susceptibility. Split-ring resonators loaded with transistors are shown theoretically and experimentally to act as metamaterials with a second-order nonlinear susceptibility that can be adjusted through the use of a bias voltage. Measurements confirm that this allows for the design of a nonlinear metamaterial with adjustable mixing efficiency.

  11. Measurement of the shot noise in a single electron transistor

    OpenAIRE

    Kafanov, Sergey; Delsing, Per

    2008-01-01

    We have systematically measured the shot noise in a single electron transistor (SET) as a function of bias and gate voltages. By embedding a SET in a resonance circuit we have been able to measure its shot noise at the resonance frequency 464 MHz, where the 1/f noise is negligible. We can extract the Fano factor which varies between 0.5 and 1 depending on the amount of Coulomb blockade in the SET, in very good agreement with the theory.

  12. Doping To Reduce Base Resistances Of Bipolar Transistors

    Science.gov (United States)

    Lin, True-Lon

    1991-01-01

    Modified doping profile proposed to reduce base resistance of bipolar transistors. A p/p+ base-doping profile reduces base resistance without reducing current gain. Proposed low/high base-doping profile realized by such low-temperature deposition techniques as molecular-beam epitaxy, ultra-high-vacuum chemical-vapor deposition, and limited-reaction epitaxy. Produces desired doping profiles without excessive diffusion of dopant.

  13. Osteoblastic cells trigger gate currents on nanocrystalline diamond transistor

    Czech Academy of Sciences Publication Activity Database

    Ižák, Tibor; Krátká, Marie; Kromka, Alexander; Rezek, Bohuslav

    2015-01-01

    Roč. 129, May (2015), 95-99. ISSN 0927-7765 R&D Projects: GA ČR GAP108/12/0996 Grant ostatní: AVČR(CZ) M100101209 Institutional support: RVO:68378271 Keywords : field-effect transistors * nanocrystalline diamond * osteoblastic cells * leakage currents Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.152, year: 2014

  14. Intrinsic graphene field effect transistor on amorphous carbon films

    OpenAIRE

    Tinchev, Savcho

    2013-01-01

    Fabrication of graphene field effect transistor is described which uses an intrinsic graphene on the surface of as deposited hydrogenated amorphous carbon films. Ambipolar characteristic has been demonstrated typical for graphene devices, which changes to unipolar characteristic if the surface graphene was etched in oxygen plasma. Because amorphous carbon films can be growth easily, with unlimited dimensions and no transfer of graphene is necessary, this can open new perspective for graphene ...

  15. Liquid crystals for organic thin-film transistors

    OpenAIRE

    Iino, Hiroaki; Usui, Takayuki; Hanna, Jun-ichi

    2015-01-01

    Crystalline thin films of organic semiconductors are a good candidate for field effect transistor (FET) materials in printed electronics. However, there are currently two main problems, which are associated with inhomogeneity and poor thermal durability of these films. Here we report that liquid crystalline materials exhibiting a highly ordered liquid crystal phase of smectic E (SmE) can solve both these problems. We design a SmE liquid crystalline material, 2-decyl-7-phenyl-[1]benzothieno[3,...

  16. Modeling of non-uniform heat generation in LDMOS transistors

    Science.gov (United States)

    Roig, J.; Flores, D.; Urresti, J.; Hidalgo, S.; Rebollo, J.

    2005-01-01

    This work is devoted to the heat dissipation analysis in LDMOS transistors operating at high current conditions. Hence, a new expression for the Joule heat generated by electron current is provided to simplify the LDMOS electro-thermal modeling, thus giving physical insight and predicting hot spots. The model is based on the semiconductor physics and the required input data are the device geometrical and technological parameters as well as the applied bias.

  17. Dynamics of Bloch oscillating transistor near the bifurcation threshold

    OpenAIRE

    Sarkar, Jayanta; Puska, Antti; Hassel, Juha; Hakonen, Pertti J.

    2013-01-01

    The tendency to bifurcate can often be utilized to improve performance characteristics of amplifiers or even to build detectors. The Bloch oscillating transistor is such a device. Here, we show that bistable behavior can be approached by tuning the base current and that the critical value depends on the Josephson coupling energy EJ of the device. We demonstrate current-gain enhancement for the device operating near the bifurcation point at small EJ. From our results for the current gains at v...

  18. Fabrication of SWCNT-Graphene Field-Effect Transistors

    OpenAIRE

    Shuangxi Xie; Niandong Jiao; Steve Tung; Lianqing Liu

    2015-01-01

    Graphene and single-walled carbon nanotube (SWCNT) have been widely studied because of their extraordinary electrical, thermal, mechanical, and optical properties. This paper describes a novel and flexible method to fabricate all-carbon field-effect transistors (FETs). The fabrication process begins with assembling graphene grown by chemical vapor deposition (CVD) on a silicon chip with SiO2 as the dielectric layer and n-doped Si substrate as the gate. Next, an atomic force microscopy (AFM)-b...

  19. Tunneling phenomena in carbon nanotube field-effect transistors

    OpenAIRE

    Knoch, Joachim; Appenzeller, Joerg

    2008-01-01

    In the present article we will discuss the electronic transport properties of carbon nanotube field-effect transistors (CNFETs). Three different device concepts will be studied in more detail: Schottky-barrier CNFETs with metallic source and drain contacts, conventional-type CNFETs with doped nanotube segments as source and drain electrodes and finally a new concept, the tunneling CNFET. As it turns out, tunneling phenomena play a prominent role in all three CNFET designs and determine their ...

  20. Simulation of graphene nanoribbon field-effect transistors

    OpenAIRE

    Fiori G.; Iannaccone G.

    2007-01-01

    We present an atomistic three-dimensional simulation of graphene nanoribbon field effect transistors (GNR-FETs), based on the self-consistent solution of the 3D Poisson and Schroedinger equation with open boundary conditions within the non-equilibrium Green's Function formalism and a tight-binding hamiltonian. With respect to carbon nanotube FETs, GNR-FETs exhibit comparable performance, reduced sensitivity on the variability of channel chirality, and similar leakage problems due to band-to-b...

  1. A scheme for a topological insulator field effect transistor

    Science.gov (United States)

    Vali, Mehran; Dideban, Daryoosh; Moezi, Negin

    2015-05-01

    We propose a scheme for a topological insulator field effect transistor. The idea is based on the gate voltage control of the Dirac fermions in a ferromagnetic topological insulator channel with perpendicular magnetization connecting to two metallic topological insulator leads. Our theoretical analysis shows that the proposed device displays a switching effect with high on/off current ratio and a negative differential conductance with a good peak to valley ratio.

  2. Wavy channel transistor for area efficient high performance operation

    KAUST Repository

    Fahad, Hossain M.

    2013-04-05

    We report a wavy channel FinFET like transistor where the channel is wavy to increase its width without any area penalty and thereby increasing its drive current. Through simulation and experiments, we show the effectiveness of such device architecture is capable of high performance operation compared to conventional FinFETs with comparatively higher area efficiency and lower chip latency as well as lower power consumption.

  3. CURRENT PATH IN AMORPHOUS-SILICON FIELD EFFECT TRANSISTORS

    OpenAIRE

    M. MATSUMURA; Kuno, S.; Uchida, Y.

    1981-01-01

    On-resistance of amorphous-silicon field effect transistors with staggered electrodes was investigated. It was found that dependences of the on-resistance on geometrical parameters were classified into two groups. The origin was attributed to the residual resistance between the n+ electrode and the channel which was formed at the silicon-silicon dioxide interface. The resistance was analyzed by taking space charge effect into account, and we found that it changes in accordance with sample pre...

  4. Theoretical Study of Phosphorene Tunneling Field Effect Transistors

    OpenAIRE

    Chang, Jiwon; Hobbs, Chris

    2015-01-01

    In this work, device performances of tunneling field effect transistors (TFETs) based on phosphorene are explored via self-consistent atomistic quantum transport simulations. Phosphorene is an ultra-thin two-dimensional (2-D) material with a direct band gap suitable for TFETs applications. Our simulation shows that phosphorene TFETs exhibit subthreshold slope (SS) below 60 mV/dec and a wide range of on-current depending on the transport direction due to highly anisotropic band structures of p...

  5. Advances in organic field-effect transistors and integrated circuits

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Organic field-effect transistors (OFETs) have received significant research interest because of their promising applications in low cast, lager area, plastic circuits, and tremendous progress has been made in materials, device performance, OFETs based circuits in recent years. In this article we introduce the advances in organic semiconductor materials, OFETs based integrating techniques, and in particular highlight the recent progress. Finally, the prospects and problems of OFETs are discussed.

  6. Organic Field-effect Transistors Based on Tetrathiafulvalene Derivatives

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Restults Tetrathiafulvalene (TTF) and its derivatives have been extensively investigated in the field of organic conductors and superconductors since 1973. Recently, their application in organic field-effect transistors (OFETs) has attracted considerable attention. So far, on the one hand, the fabrication techniques of the TTF-based FETs have been primarily limited to high vacuum evaporation, which is a relatively expensive process. On the other hand, low FET performances, such as the low on/off ratio...

  7. Organic thin film transistor integration a hybrid approach

    CERN Document Server

    Li, Flora; Wu, Yiliang; Ong, Beng S

    2013-01-01

    Research on organic electronics (or plastic electronics) is driven by the need to create systems that are lightweight, unbreakable, and mechanically flexible. With the remarkable improvement in the performance of organic semiconductor materials during the past few decades, organic electronics appeal to innovative, practical, and broad-impact applications requiring large-area coverage, mechanical flexibility, low-temperature processing, and low cost. Thus, organic electronics appeal to a broad range of electronic devices and products including transistors, diodes, sensors, solar cells, lighting

  8. InP Heterojunction Bipolar Transistor Amplifiers to 255 GHz

    Science.gov (United States)

    Radisic, Vesna; Sawdai, Donald; Scott, Dennis; Deal, William; Dang, Linh; Li, Danny; Cavus, Abdullah; To, Richard; Lai, Richard

    2009-01-01

    Two single-stage InP heterojunction bipolar transistor (HBT) amplifiers operate at 184 and 255 GHz, using Northrop Grumman Corporation s InP HBT MMIC (monolithic microwave integrated circuit) technology. At the time of this reporting, these are reported to be the highest HBT amplifiers ever created. The purpose of the amplifier design is to evaluate the technology capability for high-frequency designs and verify the model for future development work.

  9. Single shot measurement of a silicon single electron transistor

    OpenAIRE

    Hasko, D. G.; Ferrus, T.; Morrissey, Q. R.; Burge, S. R.; Freeman, E. J.; French, M. J.; Lam, A; Creswell, L.; Collier, R J; Williams, D.A.; Briggs, G. A. D.

    2008-01-01

    We have fabricated a custom cryogenic Complementary Metal-Oxide-Semiconductor (CMOS) integrated circuit that has a higher measurement bandwidth compared with conventional room temperature electronics. This allowed implementing single shot operations and observe the real-time evolution of the current of a phosphorous-doped silicon single electron transistor that was irradiated with a microwave pulse. Relaxation times up to 90 us are observed, suggesting the presence of well isolated electron e...

  10. First-principles modelling of molecular single-electron transistors

    OpenAIRE

    Stokbro, Kurt

    2010-01-01

    We present a first-principles method for calculating the charging energy of a molecular single-electron transistor operating in the Coulomb blockade regime. The properties of the molecule are modeled using density-functional theory, the environment is described by a continuum model, and the interaction between the molecule and the environment are included through the Poisson equation. The model is used to calculate the charge stability diagrams of a benzene and C$_{60}$ molecular single-elect...

  11. Transistor electronics use of semiconductor components in switching operations

    CERN Document Server

    Rumpf, Karl-Heinz

    2014-01-01

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

  12. Organic field-effect transistors using single crystals

    International Nuclear Information System (INIS)

    Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs), the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20-40 cm2 Vs-1, achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR) measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps. (topical review)

  13. Lead iodide perovskite light-emitting field-effect transistor

    Science.gov (United States)

    Chin, Xin Yu; Cortecchia, Daniele; Yin, Jun; Bruno, Annalisa; Soci, Cesare

    2015-06-01

    Despite the widespread use of solution-processable hybrid organic-inorganic perovskites in photovoltaic and light-emitting applications, determination of their intrinsic charge transport parameters has been elusive due to the variability of film preparation and history-dependent device performance. Here we show that screening effects associated to ionic transport can be effectively eliminated by lowering the operating temperature of methylammonium lead iodide perovskite (CH3NH3PbI3) field-effect transistors. Field-effect carrier mobility is found to increase by almost two orders of magnitude below 200 K, consistent with phonon scattering-limited transport. Under balanced ambipolar carrier injection, gate-dependent electroluminescence is also observed from the transistor channel, with spectra revealing the tetragonal to orthorhombic phase transition. This demonstration of CH3NH3PbI3 light-emitting field-effect transistors provides intrinsic transport parameters to guide materials and solar cell optimization, and will drive the development of new electro-optic device concepts, such as gated light-emitting diodes and lasers operating at room temperature.

  14. Infrared light gated MoS₂ field effect transistor.

    Science.gov (United States)

    Fang, Huajing; Lin, Ziyuan; Wang, Xinsheng; Tang, Chun-Yin; Chen, Yan; Zhang, Fan; Chai, Yang; Li, Qiang; Yan, Qingfeng; Chan, H L W; Dai, Ji-Yan

    2015-12-14

    Molybdenum disulfide (MoS₂) as a promising 2D material has attracted extensive attentions due to its unique physical, optical and electrical properties. In this work, we demonstrate an infrared (IR) light gated MoS₂ transistor through a device composed of MoS₂ monolayer and a ferroelectric single crystal Pb(Mg(1/3)Nb(2/3))O₃-PbTiO₃ (PMN-PT). With a monolayer MoS₂ onto the top surface of (111) PMN-PT crystal, the drain current of MoS₂ channel can be modulated with infrared illumination and this modulation process is reversible. Thus, the transistor can work as a new kind of IR photodetector with a high IR responsivity of 114%/Wcm⁻². The IR response of MoS₂ transistor is attributed to the polarization change of PMN-PT single crystal induced by the pyroelectric effect which results in a field effect. Our result promises the application of MoS₂ 2D material in infrared optoelectronic devices. Combining with the intrinsic photocurrent feature of MoS₂ in the visible range, the MoS₂ on ferroelectric single crystal may be sensitive to a broadband wavelength of light. PMID:26698982

  15. Top gated graphene transistors with different gate insulators

    Energy Technology Data Exchange (ETDEWEB)

    Pezoldt, Joerg; Hanisch, Antonia [FG Festkoerperelektronik, Institut fuer Mikro- und Nanotechnologien, TU Ilmenau, Postfach 100565, 98684 Ilmenau (Germany); Hummel, Christian; Schwierz, Frank [FG Nanotechnologie, Institut fuer Mikro- und Nanotechnologien, TU Ilmenau, Postfach 100565, 98684 Ilmenau (Germany); Hotovy, Ivan; Kadlecikova, Magdalena [Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, Ilkovicova 3, Bratislava 812 19 (Slovakia)

    2010-02-15

    Top gated graphene field effect transistors with AlN and Si{sub 3}N{sub 4} gate insulator materials were fabricated by plasma assisted deposition. Transistors with an AlN top gate insulator showed a reduced mobility and channel carrier density, whereas for the transistors with Si{sub 3}N{sub 4} dielectric an increase of the mobility and a decrease of the channel carrier density was observed. The reduced carrier density can be explained by bond formation between the insulator and the graphene sheets. The different behaviour of the carrier mobility is due to defect passivation by H{sub 2} in case of Si{sub 3}N{sub 4} and defect formation in the graphene channel for the AlN gate insulator. A reduced transconductance in top gate device configurations compared to the back gate configurations was observed, which can be caused by the Klein paradox or differences in the trap densities in the top gate insulators. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  16. Organic field-effect transistors using single crystals

    Directory of Open Access Journals (Sweden)

    Tatsuo Hasegawa and Jun Takeya

    2009-01-01

    Full Text Available Organic field-effect transistors using small-molecule organic single crystals are developed to investigate fundamental aspects of organic thin-film transistors that have been widely studied for possible future markets for 'plastic electronics'. In reviewing the physics and chemistry of single-crystal organic field-effect transistors (SC-OFETs, the nature of intrinsic charge dynamics is elucidated for the carriers induced at the single crystal surfaces of molecular semiconductors. Materials for SC-OFETs are first reviewed with descriptions of the fabrication methods and the field-effect characteristics. In particular, a benchmark carrier mobility of 20–40 cm2 Vs−1, achieved with thin platelets of rubrene single crystals, demonstrates the significance of the SC-OFETs and clarifies material limitations for organic devices. In the latter part of this review, we discuss the physics of microscopic charge transport by using SC-OFETs at metal/semiconductor contacts and along semiconductor/insulator interfaces. Most importantly, Hall effect and electron spin resonance (ESR measurements reveal that interface charge transport in molecular semiconductors is properly described in terms of band transport and localization by charge traps.

  17. Ferroelectric Field-Effect Transistor Differential Amplifier Circuit Analysis

    Science.gov (United States)

    Phillips, Thomas A.; MacLeod, Todd C.; Ho, Fat D.

    2008-01-01

    There has been considerable research investigating the Ferroelectric Field-Effect Transistor (FeFET) in memory circuits. However, very little research has been performed in applying the FeFET to analog circuits. This paper investigates the use of FeFETs in a common analog circuit, the differential amplifier. The two input Metal-Oxide-Semiconductor (MOS) transistors in a general MOS differential amplifier circuit are replaced with FeFETs. Resistors are used in place of the other three MOS transistors. The FeFET model used in the analysis has been previously reported and was based on experimental device data. Because of the FeFET hysteresis, the FeFET differential amplifier has four different operating modes depending on whether the FeFETs are positively or negatively polarized. The FeFET differential amplifier operation in the different modes was analyzed by calculating the amplifier voltage transfer and gain characteristics shown in figures 2 through 5. Comparisons were made between the FeFET differential amplifier and the standard MOS differential amplifier. Possible applications and benefits of the FeFET differential amplifier are discussed.

  18. Organic transistors with high thermal stability for medical applications

    Science.gov (United States)

    Kuribara, Kazunori; Wang, He; Uchiyama, Naoya; Fukuda, Kenjiro; Yokota, Tomoyuki; Zschieschang, Ute; Jaye, Cherno; Fischer, Daniel; Klauk, Hagen; Yamamoto, Tatsuya; Takimiya, Kazuo; Ikeda, Masaaki; Kuwabara, Hirokazu; Sekitani, Tsuyoshi; Loo, Yueh-Lin; Someya, Takao

    2012-03-01

    The excellent mechanical flexibility of organic electronic devices is expected to open up a range of new application opportunities in electronics, such as flexible displays, robotic sensors, and biological and medical electronic applications. However, one of the major remaining issues for organic devices is their instability, especially their thermal instability, because low melting temperatures and large thermal expansion coefficients of organic materials cause thermal degradation. Here we demonstrate the fabrication of flexible thin-film transistors with excellent thermal stability and their viability for biomedical sterilization processes. The organic thin-film transistors comprise a high-mobility organic semiconductor, dinaphtho[2,3-b:2‧,3‧-f]thieno[3,2-b]thiophene, and thin gate dielectrics comprising a 2-nm-thick self-assembled monolayer and a 4-nm-thick aluminium oxide layer. The transistors exhibit a mobility of 1.2 cm2 V-1s-1 within a 2 V operation and are stable even after exposure to conditions typically used for medical sterilization.

  19. Sidewall spacer optimization for steep switching junctionless transistors

    Science.gov (United States)

    Gupta, Manish; Kranti, Abhinav

    2016-06-01

    In this work, we analyze the impact of a high permittivity (high-κ) sidewall spacer and gate dielectric on the occurrence of sub-60 mV/decade subthreshold swing (S-swing) in symmetrical junctionless (JL) double gate (DG) transistors. It is shown that steep S-swing values (≤10 mV/decade) can be achieved in JL devices with a combination of a high permittivity (high-κ) gate dielectric and a narrow low permittivity (low-κ) sidewall spacer. Implementation of a wider high-κ spacer will diminish the degree of impact ionization by the influence of the fringing component of the gate electric field, and will not be useful for steep off-to-on current transition. A wider spacer with low-κ and a narrow spacer with high-κ permittivity will be useful to limit the latching effect that can occur at lower temperatures (250 K). For high temperature operation, the decrease in the impact ionization rate can be compensated by designing a JL transistor with a thicker silicon film. The work demonstrates opportunities to enhance impact ionization at sub bandgap voltages, and proposes optimal guidelines for selecting a sidewall spacer to facilitate steep switching in JL transistors.

  20. Single-layer MoS2 transistors.

    Science.gov (United States)

    Radisavljevic, B; Radenovic, A; Brivio, J; Giacometti, V; Kis, A

    2011-03-01

    Two-dimensional materials are attractive for use in next-generation nanoelectronic devices because, compared to one-dimensional materials, it is relatively easy to fabricate complex structures from them. The most widely studied two-dimensional material is graphene, both because of its rich physics and its high mobility. However, pristine graphene does not have a bandgap, a property that is essential for many applications, including transistors. Engineering a graphene bandgap increases fabrication complexity and either reduces mobilities to the level of strained silicon films or requires high voltages. Although single layers of MoS(2) have a large intrinsic bandgap of 1.8 eV (ref. 16), previously reported mobilities in the 0.5-3 cm(2) V(-1) s(-1) range are too low for practical devices. Here, we use a halfnium oxide gate dielectric to demonstrate a room-temperature single-layer MoS(2) mobility of at least 200 cm(2) V(-1) s(-1), similar to that of graphene nanoribbons, and demonstrate transistors with room-temperature current on/off ratios of 1 × 10(8) and ultralow standby power dissipation. Because monolayer MoS(2) has a direct bandgap, it can be used to construct interband tunnel FETs, which offer lower power consumption than classical transistors. Monolayer MoS(2) could also complement graphene in applications that require thin transparent semiconductors, such as optoelectronics and energy harvesting. PMID:21278752

  1. Bipolar junction transistor models for circuit simulation of cosmic-ray-induced soft errors

    Science.gov (United States)

    Benumof, R.; Zoutendyk, J.

    1984-01-01

    This paper examines bipolar junction transistor models suitable for calculating the effects of large excursions of some of the variables determining the operation of a transistor. Both the Ebers-Moll and Gummel-Poon models are studied, and the junction and diffusion capacitances are evaluated on the basis of the latter model. The most interesting result of this analysis is that a bipolar junction transistor when struck by a cosmic particle may cause a single event upset in an electronic circuit if the transistor is operated at a low forward base-emitter bias.

  2. Reliable strain measurement in transistor arrays by robust scanning transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    Suhyun Kim

    2013-09-01

    Full Text Available Accurate measurement of the strain field in the channels of transistor arrays is critical for strain engineering in modern electronic devices. We applied atomic-resolution high-angle annular dark-field scanning transmission electron microscopy to quantitative measurement of the strain field in transistor arrays. The quantitative strain profile over 20 transistors was obtained with high reliability and a precision of 0.1%. The strain field was found to form homogeneously in the channels of the transistor arrays. Furthermore, strain relaxation due to the thin foil effect was quantitatively investigated for thicknesses of 35 to 275 nm.

  3. High-performance carbon nanotube thin-film transistors on flexible paper substrates

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Na; Yun, Ki Nam; Yu, Hyun-Yong; Lee, Cheol Jin, E-mail: cjlee@korea.ac.kr [School of Electrical Engineering, Korea University, Seoul 136-713 (Korea, Republic of); Shim, Joon Hyung [School of Mechanical Engineering, Korea University, Seoul 136-713 (Korea, Republic of)

    2015-03-09

    Single-walled carbon nanotubes (SWCNTs) are promising materials as active channels for flexible transistors owing to their excellent electrical and mechanical properties. However, flexible SWCNT transistors have never been realized on paper substrates, which are widely used, inexpensive, and recyclable. In this study, we fabricated SWCNT thin-film transistors on photo paper substrates. The devices exhibited a high on/off current ratio of more than 10{sup 6} and a field-effect mobility of approximately 3 cm{sup 2}/V·s. The proof-of-concept demonstration indicates that SWCNT transistors on flexible paper substrates could be applied as low-cost and recyclable flexible electronics.

  4. Self-assembled molecular monolayers as ultrathin gate dielectric in carbon nanotube transistors

    Science.gov (United States)

    Robert, Gaël; Derycke, Vincent; Goffman, Marcelo F.; Lenfant, Stéphane; Vuillaume, Dominique; Bourgoin, Jean-Philippe

    2008-10-01

    We demonstrate the use of a self-assembled monolayer of octadecanethiol on gold as thin gate dielectric for a single-walled carbon nanotube field-effect transistor. P-type transistors display very steep subthreshold slopes, greatly reduced hysteresis, and band-to-band tunneling. The suppression of the gate efficiency for n-type transistors emphasizes the key role of the electrical dipole of the molecular layer in controlling the switching. Combining the versatility of organic dielectrics with the exceptional electronic and mechanical properties of carbon nanotubes opens interesting ways toward the realization of fully organic nanoscale transistors.

  5. Terahertz Detection of Quantum Cascade Laser Emission by Plasma Waves in Field Effect Transistors

    OpenAIRE

    Teppe, Frederic; Consejo, Christophe; Torres, J; Chenaud, Boris; Solignac, Pierre; Fathololoumi, S; Wasilewski, Z. R.; Zholudev, Maksim; Diakonova, Nina; Coquillat, Dominique; El Fatimy, Abdelouahad; Buzatu, Petre; CHAUBET, Christophe; Knap, Wojciech

    2011-01-01

    We report on the resonant detection of a 3.1 THz radiation produced by a quantum cascade laser using a 250 nm gate length GaAs/AlGaAs field effect transistor at liquid nitrogen temperature. We show that the physical mechanism of the detection is related to the plasma waves excited in the transistor channel. The detection is enhanced by increasing the drain current and driving the transistor into saturation regime. These results clearly show that plasma wave nanometer-size transistors can be u...

  6. Transistor-based filter for inhibiting load noise from entering a power supply

    Science.gov (United States)

    Taubman, Matthew S

    2013-07-02

    A transistor-based filter for inhibiting load noise from entering a power supply is disclosed. The filter includes a first transistor having an emitter coupled to a power supply, a collector coupled to a load, and a base. The filter also includes a first capacitor coupled between the base of the first transistor and a ground terminal. The filter further includes an impedance coupled between the base and a node between the collector and the load, or a second transistor and second capacitor. The impedance can be a resistor or an inductor.

  7. Thin film transistors of single-walled carbon nanotubes grown directly on glass substrates

    International Nuclear Information System (INIS)

    We report a transistor of randomly networked single-walled carbon nanotubes on a glass substrate. The carbon nanotube networks acting as the active components of the thin film transistor were selectively formed on the transistor channel areas that were previously patterned with catalysts to avoid the etching process for isolating nanotubes. The nanotube density was more than 50 μm-2, which is much larger than the percolation threshold. Transistors were successfully fabricated with a conducting and transparent ZnO for the back-side gate and the top-side gate. This allows the transparent electronics or suggests thin film applications of nanotubes for future opto-electronics

  8. Electrically controlled spin-transistor operation in a helical magnetic field

    International Nuclear Information System (INIS)

    A proposal of an electrically controlled spin transistor in a helical magnetic field is presented. In the proposed device, the transistor action is driven by the Landau–Zener transitions that lead to a backscattering of spin polarized electrons and switching the transistor into the high-resistance state (off state). The on/off state of the transistor can be controlled by the all-electric means using Rashba spin–orbit coupling that can be tuned by the voltages applied to the side electrodes. (paper)

  9. Terahertz detection of magnetic field-driven topological phase transition in HgTe-based transistors

    International Nuclear Information System (INIS)

    We report on terahertz photoconductivity under magnetic field up to 16 T of field effect transistor based on HgTe quantum well (QW) with an inverted band structure. We observe pronounced cyclotron resonance and Shubnikov-de Haas-like oscillations, indicating a high mobility electron gas in the transistor channel. We discover that nonlinearity of the transistor channel allows for observation of characteristic features in photoconductivity at critical magnetic field corresponding to the phase transition between topological quantum spin Hall and trivial quantum Hall states in HgTe QW. Our results pave the way towards terahertz topological field effect transistors

  10. Neutron Radiation Effect On 2N2222 And NTE 123 NPN Silicon Bipolar Junction Transistors

    International Nuclear Information System (INIS)

    This paper examines neutron radiation with PTS (Pneumatic Transfer System) effect on silicon NPN bipolar junction transistors (2N2222 and NTE 123) and analysis of the transistors in terms of electrical characterization such as current gain after neutron radiation. The key parameters are measured with Keithley 4200SCS. Experiment results show that the current gain degradation of the transistors is very sensitive to neutron radiation. The neutron radiation can cause displacement damage in the bulk layer of the transistor structure. The current degradation is believed to be governed by increasing recombination current between the base and emitter depletion region

  11. High-performance carbon nanotube thin-film transistors on flexible paper substrates

    International Nuclear Information System (INIS)

    Single-walled carbon nanotubes (SWCNTs) are promising materials as active channels for flexible transistors owing to their excellent electrical and mechanical properties. However, flexible SWCNT transistors have never been realized on paper substrates, which are widely used, inexpensive, and recyclable. In this study, we fabricated SWCNT thin-film transistors on photo paper substrates. The devices exhibited a high on/off current ratio of more than 106 and a field-effect mobility of approximately 3 cm2/V·s. The proof-of-concept demonstration indicates that SWCNT transistors on flexible paper substrates could be applied as low-cost and recyclable flexible electronics

  12. Terahertz detection of magnetic field-driven topological phase transition in HgTe-based transistors

    Energy Technology Data Exchange (ETDEWEB)

    Kadykov, A. M. [Laboratoire Charles Coulomb (L2C), UMR CNRS 5221, Universite Montpellier, 34095 Montpellier (France); Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, Nizhny Novgorod 603950 (Russian Federation); Teppe, F., E-mail: frederic.teppe@univ-montp2.fr; Consejo, C.; Ruffenach, S.; Marcinkiewicz, M.; Desrat, W.; Dyakonova, N.; Knap, W. [Laboratoire Charles Coulomb (L2C), UMR CNRS 5221, Universite Montpellier, 34095 Montpellier (France); Viti, L.; Vitiello, M. S. [NEST, Istituto Nanoscienze-CNR and Scuola Normale Superiore, I-56127 Pisa (Italy); Krishtopenko, S. S.; Morozov, S. V.; Gavrilenko, V. I. [Institute for Physics of Microstructures, Russian Academy of Sciences, GSP-105, Nizhny Novgorod 603950 (Russian Federation); Lobachevsky State University, 23 Prospekt Gagarina, 603950 Nizhny Novgorod (Russian Federation); Mikhailov, N. N.; Dvoretsky, S. A. [Institute of Semiconductor Physics, Siberian Branch, Russian Academy of Sciences, pr. Akademika Lavrent' eva 13, Novosibirsk 630090 (Russian Federation)

    2015-10-12

    We report on terahertz photoconductivity under magnetic field up to 16 T of field effect transistor based on HgTe quantum well (QW) with an inverted band structure. We observe pronounced cyclotron resonance and Shubnikov-de Haas-like oscillations, indicating a high mobility electron gas in the transistor channel. We discover that nonlinearity of the transistor channel allows for observation of characteristic features in photoconductivity at critical magnetic field corresponding to the phase transition between topological quantum spin Hall and trivial quantum Hall states in HgTe QW. Our results pave the way towards terahertz topological field effect transistors.

  13. Multi-channel spintronic transistor design based on magnetoelectric barriers and spin-orbital effects

    International Nuclear Information System (INIS)

    We present a spin transistor design based on spin-orbital interactions in a two-dimensional electron gas, with magnetic barriers induced by a patterned ferromagnetic gate. The proposed device overcomes certain shortcomings of previous spin transistor designs such as long device length and degradation of conductance modulation for multi-channel transport. The robustness of our device for multi-channel transport is unique in spin transistor designs based on spin-orbit coupling. The device is more practical in fabrication and experimental respects compared to previously conceived single-mode spin transistors

  14. Field-effect transistor chemical sensors of single nanoribbon of copper phthalocyanine

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Copper phthalocyanine (CuPc) nanoribbon field-effect transistors were implemented as chemical sensors. They showed fast response and high reversibility in the detection of the tetrahydrofuran atmosphere at room temperature. The drain current of the field-effect transistor sensor decreased from 6.7 to 0.2 nA when the transistor was measured under the tetrahydrofuran atmosphere. The sensor was self-refreshable in a few minutes. These results demonstrate that the organic single crystalline nanoribbon transistors could effectively act as chemical sensors.

  15. Thermal analytic model of current gain for bipolar junction transistor-bipolar static induction transistor compound device

    International Nuclear Information System (INIS)

    This paper proposes a thermal analytical model of current gain for bipolar junction transistor-bipolar static induction transistor (BJT-BSIT) compound device in the low current operation. It also proposes a best thermal compensating factor to the compound device that indicates the relationship between the thermal variation rate of current gain and device structure. This is important for the design of compound device to be optimized. Finally, the analytical model is found to be in good agreement with numerical simulation and experimental results. The test results demonstrate that thermal variation rate of current gain is below 10% in 25 °C–85°C and 20% in −55°C–25°C. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  16. Optimization of ultra-low-power CMOS transistors

    International Nuclear Information System (INIS)

    Ultra-low-power CMOS integrated circuits have constantly gained importance due to the fast growing portable electronics market. High-performance applications like mobile telephones ask for high-speed computations and low stand-by power consumption to increase the actual operating time. This means that transistors with low leakage currents and high drive currents have to be provided. Common fabrication methods will soon reach their limits if the on-chip feature size of CMOS technology continues to shrink at this very fast rate. New device architectures will help to keep track with the roadmap of the semiconductor industry. Especially doping profiles offer much freedom for performance improvements as they determine the 'inner functioning' of a transistor. In this work automated doping profile optimization is performed on MOS transistors within the TCAD framework SIESTA. The doping between and under the source/drain wells is discretized on an orthogonal optimization grid facilitating almost arbitrary two-dimensional shapes. A linear optimizer issued to find the optimum doping profile by variation of the doping parameters utilizing numerical device simulations with MINIMOS-NT. Gaussian functions are used in further optimization runs to make the doping profiles smooth. Two device generations are considered, one with 0.25 μm, the other with 0.1 μm gate length. The device geometries and source/drain doping profiles are kept fixed during optimization and supply voltages are chosen suitable for ultra-low-power purposes. In a first optimization study the drive current of NMOS transistors is maximized while keeping the leakage current below a limit of 1 pA/μm. This results in peaking channel doping devices (PCD) with narrow doping peaks placed asymmetrically in the channel. Drive current improvements of 45 % and 71 % for the 0.25 μm and 0.1 μm devices, respectively, are achieved compared to uniformly doped devices. The PCD device is studied in detail and explanations for

  17. High current and voltage effects in heterojunction bipolar transistor collectors

    International Nuclear Information System (INIS)

    The influence of temperature on speed and power applications is important in heterojunction bipolar transistors with the need for high current drive capability, high cutoff frequency and high voltage handling capability. At high current density, the onset of the Kirk effect is often the main power constraint in the bipolar transistor. An analytical model that accurately describes the physics behind the parasitic electron barrier formation in double heterojunction bipolar transistors in the Si/SiGe, GalnP/GaAs and InP/GaAsSb materials systems at the onset of the Kirk effect is presented. A new lateral current spreading effect due to the electron barrier dependence on collector current density is also discussed. The electron saturation velocity in Ga0.52In0.48P has also been measured as a function of temperature, utilising the Kirk effect in double heterojunction bipolar transistors. An AIGaAs base was used to eliminate the conduction band spike and measurements were carefully performed using pulse biasing to minimise device self-heating. Voltage drops across the base and collector series resistances were also taken into account. The measured room temperature saturation velocity of 5.0 x 106 cm/s decreased rapidly to 2.9 x 106 cm/s at 200 deg C. These results are particularly important for the prediction of frequency performance of Ga0.52In0.48P/(Al)GaAs/Ga0.52In0.48P DHBTs. Avalanche multiplication and hence impact ionisation coefficients for In0.53Ga0.47As have been determined from photomultiplication measurements over the temperature range of 20 - 400 K for a series of p-i-n/n-i-p diodes. Negative temperature dependence is observed in both the electron and hole multiplication of In0.53Ga0.47As at electric fields over 200 kV/cm, contrary to the temperature dependence of collector multiplication previously observed in InP/In0.53Ga0.47As heterojunction bipolar transistors. The results also showed that the breakdown voltage for In0.53Ga0.47As is comparable to GaAs at

  18. A 0.5-V Six-Transistor Static Random Access Memory with Ferroelectric-Gate Field Effect Transistors

    Science.gov (United States)

    Tanakamaru, Shuhei; Hatanaka, Teruyoshi; Yajima, Ryoji; Miyaji, Kousuke; Takahashi, Mitsue; Sakai, Shigeki; Takeuchi, Ken

    2010-12-01

    A 0.5 V six-transistor static random access memory (6T-SRAM) with ferroelectric-gate field-effect-transistors (Fe-FETs) is proposed and experimentally demonstrated for the first time. During the read and the hold, the threshold voltage (VTH) of Fe-FETs automatically changes to increase the static noise margin (SNM) by 60%. During the stand-by, the VTH of the proposed SRAM cell increases to decrease the leakage current by 42%. In case of the read, the VTH of the read transistor decreases and increases the cell read current to achieve the fast read. During the write, the VTH of the SRAM cell dynamically changes and assist the cell data to flip, realizing a write assist function. The enlarged SNM realizes the VDD reduction by 0.11 V, which decreases the active power by 32%. The proposed SRAM layout is the same as the conventional 6T-SRAM and there is no area penalty.

  19. Electrolyte-gated polymer thin film transistors making use of ionic liquids and ionic liquid-solvent mixtures

    Science.gov (United States)

    Sayago, Jonathan; Meng, Xiang; Quenneville, Francis; Liang, Shuang; Bourbeau, Étienne; Soavi, Francesca; Cicoira, Fabio; Santato, Clara

    2015-03-01

    Electrolyte-Gated (EG) transistors, making use of electrolytes as the gating medium, are interesting for their low operation voltage. Furthermore, EG polymer transistors offer the advantage of solution processing, low cost, and mechanical flexibility. Despite the intense research activity in EG transistors, clear guidelines to correlate the properties of the materials used for the transistor channel and electrolytes with the doping effectiveness of the transistor channel are yet to be clearly established. Here, we investigate the use of room temperature ionic liquids (RTILs) based on the [TFSI] anion (namely, [EMIM][TFSI], [BMIM][TFSI], and [PYR14][TFSI]), to gate transistors making use of MEH-PPV as the channel material. Morphological studies of MEH-PPV and RTIL films showed a certain degree of segregation between the two components. All the EG transistors featured clear drain-source current modulations at voltages below 1 V. Polar solvent additives as propylene carbonate were used to improve the transistor response time.

  20. Generation System of Concentrator Photovoltaic Based on Gallium Arsenide Cells%基于砷化镓电池的聚光光伏发电系统

    Institute of Scientific and Technical Information of China (English)

    宁铎; 王辉辉; 黄建兵; 李明勇

    2011-01-01

    Solar photovoltaic power generation system for the problem of low utilization, a generation system of concentrator photovoltaic (CPV) based on gallium arsenide (GaAs) cells can be designed. The system consists of concentrating power modules, solar tracking module, inverter module. Fresnel lens concentrator power generation module 400 times by concentrating light in lcm2 GaAs after the battery,the realization of power function; sun-tracking modules and optical sensors from the head to ensure that the basic vertical sunlight through the Fresnel lens; GaAs inverter module converts DC battery AC issued. After testing, the system reached 20. 2% conversion efficiency of solar, inverter part of the realization of the exchange function of the DC variable.%针对光伏发电系统中太阳能利用率低的问题,设计了一种基于砷化镓(GaAs)电池的聚光光伏(CPV)发电系统;该系统由聚光发电模块、太阳跟踪模块和逆变模块组成;聚光发电模块采用菲涅尔透镜400倍聚光以后照射在1Cmz的砷化镓电池上,实现发电功能;太阳跟踪模块由云台和光电传感器组成,保证太阳光基本垂直通过菲涅尔透镜,逆变模块将砷化镓电池发出的直流电转换成交流电;经过测试.该系统太阳能转换效率达到20.2%,逆变部分实现了直流变交流功能.

  1. Dynamics of threshold voltage shifts in organic and amorphous silicon field-effect transistors

    NARCIS (Netherlands)

    Mathijssen, Simon G. J.; Colle, Michael; Gomes, Henrique; Smits, Edsger C. P.; de Boer, Bert; McCulloch, Iain; Bobbert, Peter A.; de Leeuw, Dago M.; Cölle, Michael

    2007-01-01

    The electrical instability of organic field-effect transistors is investigated. We observe that the threshold-voltage shift (see figure) shows a stretched-exponential time dependence under an applied gate bias. The activation energy of 0.6 eV is common for our and all other organic transistors repor

  2. Controlled n-Type Doping of Carbon Nanotube Transistors by an Organorhodium Dimer.

    Science.gov (United States)

    Geier, Michael L; Moudgil, Karttikay; Barlow, Stephen; Marder, Seth R; Hersam, Mark C

    2016-07-13

    Single-walled carbon nanotube (SWCNT) transistors are among the most developed nanoelectronic devices for high-performance computing applications. While p-type SWCNT transistors are easily achieved through adventitious adsorption of atmospheric oxygen, n-type SWCNT transistors require extrinsic doping schemes. Existing n-type doping strategies for SWCNT transistors suffer from one or more issues including environmental instability, limited carrier concentration modulation, undesirable threshold voltage control, and/or poor morphology. In particular, commonly employed benzyl viologen n-type doping layers possess large thicknesses, which preclude top-gate transistor designs that underlie high-density integrated circuit layouts. To overcome these limitations, we report here the controlled n-type doping of SWCNT thin-film transistors with a solution-processed pentamethylrhodocene dimer. The charge transport properties of organorhodium-treated SWCNT thin films show consistent n-type behavior when characterized in both Hall effect and thin-film transistor geometries. Due to the molecular-scale thickness of the organorhodium adlayer, large-area arrays of top-gated, n-type SWCNT transistors are fabricated with high yield. This work will thus facilitate ongoing efforts to realize high-density SWCNT integrated circuits. PMID:27253896

  3. Electrothermal Behavior of High-Frequency Silicon-On-Glass Transistors

    NARCIS (Netherlands)

    Nenadovic, N.

    2004-01-01

    In this thesis, research is focused on the investigation of electrothermal effects in high-speed silicon transistors. At high current levels the power dissipation in these devices can lead to heating of both the device itself and the adjacent devices. In advanced transistors these effects are becomi

  4. 1/f Noise Characterization in CMOS Transistors in 0.13μm Technology

    DEFF Research Database (Denmark)

    Citakovic, J.; Stenberg, L J; Andreani, Pietro

    2006-01-01

    Low-frequency noise has been studied on a set of n- and p-channel CMOS transistors fabricated in a 0.13μm technology. Noise measurements have been performed on transistors with different gate lengths operating under wide bias conditions, ranging from weak to strong inversion. Noise origin has been...

  5. Electrical Characteristics of Copper Phthalocyanine Thin-Film Transistors with Polyamide-6/Polytetrafluoroethylene Gate Insulator

    Institute of Scientific and Technical Information of China (English)

    YU Shun-Yang; XU Shi-Ai; MA Dong-Ge

    2007-01-01

    Polyamide-6(PA 6)/polytetrafluoroethylene is studied as a potential gate dielectric for flexible organic thin film transistors.The salne method used for the formation of organic semiconductor and gate dielectric films greatly simplifies the fabrication process of devices.The fabricated transistors show good electrical characteristics.Ambipolar behaviour is observed even when the device is operated in air.

  6. The dual role of multiple-transistor charge sharing collection in single-event transients

    Institute of Scientific and Technical Information of China (English)

    Guo Yang; Chen Jian-Jun; He Yi-Bai; Liang Bin; Liu Bi-Wei

    2013-01-01

    As technologies scale down in size,multiple-transistors being affected by a single ion has become a universal phenomenon,and some new effects are present in single event transients (SETs) due to the charge sharing collection of the adjacent multiple-transistors.In this paper,not only the off-state p-channel metal-oxide semiconductor field-effect transistor (PMOS FET),but also the on-state PMOS is struck by a heavy-ion in the two-transistor inverter chain,due to the charge sharing collection and the electrical interaction.The SET induced by striking the off-state PMOS is efficiently mitigated by the pulse quenching effect,but the SET induced by striking the on-state PMOS becomes dominant.It is indicated in this study that in the advanced technologies,the SET will no longer just be induced by an ion striking the off-state transistor,and the SET sensitive region will no longer just surround the off-state transistor either,as it is in the older technologies.We also discuss this issue in a three-transistor inverter in depth,and the study illustrates that the three-transistor inverter is still a better replacement for spacebome integrated circuit design in advanced technologies.

  7. E-Learning System for Design and Construction of Amplifier Using Transistors

    Science.gov (United States)

    Takemura, Atsushi

    2014-01-01

    This paper proposes a novel e-Learning system for the comprehensive understanding of electronic circuits with transistors. The proposed e-Learning system allows users to learn a wide range of topics, encompassing circuit theories, design, construction, and measurement. Given the fact that the amplifiers with transistors are an integral part of…

  8. The research of multilevel transistor inverter for converting energy of solar panels

    Science.gov (United States)

    Taissariyeva, K. N.; Issembergenov, N. T.

    2015-09-01

    This article considers multilevel transistor inverter for converting energy of solar panels into electroenergy. The output of multilevel transistor inverter produces the voltage of almost sinusoidal form. The primary objective of this inverter is to transform solar energy into electroenergy of industrial frequency. The analysis of received output curves of voltage for sinusoidality has been conducted.

  9. Formation of MOS-transistors with isolation of active elements by oxiden porous silicon

    Directory of Open Access Journals (Sweden)

    Novosyadlyi S. P.

    2009-06-01

    Full Text Available The superthin functional layers of MOS-transistors require qualitative isolation of active elements. The new method of formation of epitaksial structures for technology «silicon - on-isolator» is offered on the basis of porous silicon. It will allow to form three kinds of transistors — bipolar, SМОS, DМОS.

  10. Fast turn-on of an NMOS ESD protection transistor: measurements and simulations

    NARCIS (Netherlands)

    Luchies, J.R.M.; Kort, de C.G.M.; Verweij, J.F.

    1995-01-01

    The transient turn-on of the parasitic bipolar transistor of an NMOS transistor was studied. The voltages appearing at internal nodes of protection and functional circuit after application of 350 ps rise-time pulses have been measured using electro-optic sampling. For very fast transients the trigge

  11. Fabrication de transistors monoelectroniques pour la detection de charge

    Science.gov (United States)

    Richard, Jean-Philippe

    Le transistor monoelectro'nique (SET) est un candidat que l'on croyait avoir la capacite de remplacer le transistor des circuits integres actuel (MOSFET). Pour des raisons de faible gain en voltage, d'impedance de sortie elevee et de sensibilite aux fluctuations de charges, il est considere aujourd'hui qu'un hybride tirant profit des deux technologies est plus avantageux. En exploitant sa lacune d'etre sensible aux variations de charge, le SET est davantage utilise dans des applications ou la detection de charge s'avere indispensable, notamment dans les domaines de la bio-detection et de l'informatique quantique. Ce memoire presente une etude du transistor monoelectronique utilise en tant que detecteur de charge. La methode de fabrication est basee sur le procede nanodamascene developpe par Dubuc et al. [11] permettant au transistor monoelectronique de fonctionner a temperature ambiante. La temperature d'operation etant intimement liee a la geometrie du SET, la cle du procede nanodamascene reside dans le polissage chimico-mecanique (CMP) permettant de reduire l'epaisseur des SET jusqu'a des valeurs de quelques nanametres. Dans ce projet de maitrise, nous avons cependant opte pour que le SET soit opere a temperature cryogenique. Une faible temperature d'operation permet le relachement des contraintes de dimensions des dispositifs. En considerant les variations de procedes normales pouvant survenir lors de la fabrication, la temperature d'operation maximale calculee en conception s'etend de 27 K a 90 K, soit une energie de charge de 78 meV a 23 meV. Le gain du detecteur de charge etant dependant de la distance de couplage, les resultats de simulations demontrent que cette distance doit etre de 200 nm pour que la detection de charge soit optimale. Les designs concus sont ensuite fabriques sur substrat d'oxyde de silicium. Les resultats de fabrication de SET temoignent de la robustesse du procede nanodamascene. En effet, les dimensions atteintes experimentalement s

  12. Performance Analysis of Silicon and Germanium Nanowire Transistor using Crystal Orientation and Oxide Thickness

    Directory of Open Access Journals (Sweden)

    P.Theres Mary

    2014-09-01

    Full Text Available Nanowire Transistors have attracted attention due to the probable high performance and excellent controllability of device current. In this paper, we investigate the performance analysis of nanowire transistors made of silicon and germanium materials. The nanowire transistor has a 3D distribution of electron density and electrostatic potential, therefore self-consistent 3D simulations are used. Nanowire (tool is 3D Poisson self-consistent simulator which can study the 3D transport in nanowire transistor considering phonon scattering based on the effective-mass approximation. The output characteristics of the nanowire transistors are studied in detail for both Si and Ge materials for different transport orientation (i.e., 100,110,111 and varying the oxide thickness.

  13. Studying the operation characteristics and structure of vertical channel copper-phthalocyanine organic semiconductor transistor

    Institute of Scientific and Technical Information of China (English)

    ZHU Min; SONG Ming-xin; GUI Tai-long; WANG Xuan; YIN Jing-hua; WANG Dong-xing; ZHAO Hong

    2005-01-01

    The creation of Au/CuPc/Al/CuPc/structure is a perpendicular type electricity found in the channel of organic static induction transistor. In the following we analyze transistor operation characteristics and machine structural relation. The results express that the transistor drives the voltage low and has no-saturation currentvoltage characteristics. Its operation characteristics are dependant on gate bias voltage and the construction of the aluminum electrode.The vertical channel of organic static induction transistor (OSIT) , with structure of Au/CuPc/Al/CuPc/Cu, has been determined. According to the test results, the relation of its operation characteristics and device structure was analyzed. The results show that this transistor has a low driving voltage and unsaturation Ⅰ-Ⅴ characteristics. Its operation characteristics are dependant on gate bias voltage and the structure of the aluminum electrode.

  14. The total dose effects on the 1/f noise of deep submicron CMOS transistors

    International Nuclear Information System (INIS)

    Using 0.18 μm CMOS transistors, the total dose effects on the 1/f noise of deep-submicron CMOS transistors are studied for the first time in mainland China. From the experimental results and the theoretic analysis, we realize that total dose radiation causes a lot of trapped positive charges in STI (shallow trench isolation) SiO2 layers, which induces a current leakage passage, increasing the 1/f noise power of CMOS transistors. In addition, we design some radiation-hardness structures on the CMOS transistors and the experimental results show that, until the total dose achieves 750 krad, the 1/f noise power of the radiation-hardness CMOS transistors remains unchanged, which proves our conclusion. (semiconductor devices)

  15. Black Phosphorus Flexible Thin Film Transistors at Gighertz Frequencies.

    Science.gov (United States)

    Zhu, Weinan; Park, Saungeun; Yogeesh, Maruthi N; McNicholas, Kyle M; Bank, Seth R; Akinwande, Deji

    2016-04-13

    Black phosphorus (BP) has attracted rapidly growing attention for high speed and low power nanoelectronics owing to its compelling combination of tunable bandgap (0.3 to 2 eV) and high carrier mobility (up to ∼1000 cm(2)/V·s) at room temperature. In this work, we report the first radio frequency (RF) flexible top-gated (TG) BP thin-film transistors on highly bendable polyimide substrate for GHz nanoelectronic applications. Enhanced p-type charge transport with low-field mobility ∼233 cm(2)/V·s and current density of ∼100 μA/μm at VDS = -2 V were obtained from flexible BP transistor at a channel length L = 0.5 μm. Importantly, with optimized dielectric coating for air-stability during microfabrication, flexible BP RF transistors afforded intrinsic maximum oscillation frequency fMAX ∼ 14.5 GHz and unity current gain cutoff frequency fT ∼ 17.5 GHz at a channel length of 0.5 μm. Notably, the experimental fT achieved here is at least 45% higher than prior results on rigid substrate, which is attributed to the improved air-stability of fabricated BP devices. In addition, the high-frequency performance was investigated through mechanical bending test up to ∼1.5% tensile strain, which is ultimately limited by the inorganic dielectric film rather than the 2D material. Comparison of BP RF devices to other 2D semiconductors clearly indicates that BP offers the highest saturation velocity, an important metric for high-speed and RF flexible nanosystems. PMID:26977902

  16. The Reliability of III-V semiconductor Heterojunction Bipolar Transistors

    OpenAIRE

    M. Borgarino; Plana, R.; Graffeuil, J; Cattani, L; F. Fantini

    2000-01-01

    The Heterojunction Bipolar Transistor (HBT) features some characteristics that make it a very promising device in the telecom field. For these applications, the reliability is a key issue. The aim of the present paper is to summarise the most relevant reliability concerns, from whose the HBT suffers, as the stability of the ohmic contact, the presence of defects, and the stability of the base dopant. Since in the last years the Si/SiGe HBT has emerged as a strong competitor against the III-V ...

  17. Heterostructure field effect transistors based on nitride interfaces

    International Nuclear Information System (INIS)

    A key property of the nitrides is the fact that they possess large spontaneous and piezoelectric polarization fields that allow a significant tailoring of the carrier dynamics and optical properties of nitride devices. In this paper, based on first-principles calculations of structural and electronic properties of bulk nitrides and their heterostructure, we investigate the potential of this novel material class for modern device applications by performing self-consistent Monte Carlo simulations. Our studies reveal that the nitride based electronic devices have characteristics that predispose them for high power and high frequency applications. We demonstrate also that transistor characteristics are favourably influenced by the internal polarization induced electric fields. (author)

  18. Heterostructure field effect transistors based on nitride interfaces

    Science.gov (United States)

    Majewski, J. A.; Zandler, G.; Vogl, P.

    2002-04-01

    A key property of the nitrides is the fact that they possess large spontaneous and piezoelectric polarization fields that allow a significant tailoring of the carrier dynamics and optical properties of nitride devices. In this paper, based on first-principles calculations of structural and electronic properties of bulk nitrides and their heterostructure, we investigate the potential of this novel material class for modern device applications by performing self-consistent Monte Carlo simulations. Our studies reveal that the nitride based electronic devices have characteristics that predispose them for high power and high frequency applications. We demonstrate also that transistor characteristics are favourably influenced by the internal polarization induced electric fields.

  19. Heterostructure field effect transistors based on nitride interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Majewski, J.A.; Zandler, G.; Vogl, P. [Physics Department and Walter Schottky Institute, Technische Universitaet Muenchen, Garching (Germany)

    2002-05-03

    A key property of the nitrides is the fact that they possess large spontaneous and piezoelectric polarization fields that allow a significant tailoring of the carrier dynamics and optical properties of nitride devices. In this paper, based on first-principles calculations of structural and electronic properties of bulk nitrides and their heterostructure, we investigate the potential of this novel material class for modern device applications by performing self-consistent Monte Carlo simulations. Our studies reveal that the nitride based electronic devices have characteristics that predispose them for high power and high frequency applications. We demonstrate also that transistor characteristics are favourably influenced by the internal polarization induced electric fields. (author)

  20. Electronic transport in benzodifuran single-molecule transistors

    Science.gov (United States)

    Xiang, An; Li, Hui; Chen, Songjie; Liu, Shi-Xia; Decurtins, Silvio; Bai, Meilin; Hou, Shimin; Liao, Jianhui

    2015-04-01

    Benzodifuran (BDF) single-molecule transistors have been fabricated in electromigration break junctions for electronic measurements. The inelastic electron tunneling spectrum validates that the BDF molecule is the pathway of charge transport. The gating effect is analyzed in the framework of a single-level tunneling model combined with transition voltage spectroscopy (TVS). The analysis reveals that the highest occupied molecular orbital (HOMO) of the thiol-terminated BDF molecule dominates the charge transport through Au-BDF-Au junctions. Moreover, the energy shift of the HOMO caused by the gate voltage is the main reason for conductance modulation. In contrast, the electronic coupling between the BDF molecule and the gold electrodes, which significantly affects the low-bias junction conductance, is only influenced slightly by the applied gate voltage. These findings will help in the design of future molecular electronic devices.Benzodifuran (BDF) single-molecule transistors have been fabricated in electromigration break junctions for electronic measurements. The inelastic electron tunneling spectrum validates that the BDF molecule is the pathway of charge transport. The gating effect is analyzed in the framework of a single-level tunneling model combined with transition voltage spectroscopy (TVS). The analysis reveals that the highest occupied molecular orbital (HOMO) of the thiol-terminated BDF molecule dominates the charge transport through Au-BDF-Au junctions. Moreover, the energy shift of the HOMO caused by the gate voltage is the main reason for conductance modulation. In contrast, the electronic coupling between the BDF molecule and the gold electrodes, which significantly affects the low-bias junction conductance, is only influenced slightly by the applied gate voltage. These findings will help in the design of future molecular electronic devices. Electronic supplementary information (ESI) available: The fabrication procedure for BDF single

  1. Neuro-Space Mapping for Modeling Heterojunction Bipolar Transistor

    Institute of Scientific and Technical Information of China (English)

    Yan Shuxia; Cheng Qianfu; Wu Haifeng; Zhang Qijun

    2015-01-01

    A neuro-space mapping(Neuro-SM) for modeling heterojunction bipolar transistor(HBT) is presented, which can automatically modify the input signals of the given model by neural network. The novel Neuro-SM formu-lations for DC and small-signal simulation are proposed to obtain the mapping network. Simulation results show that the errors between Neuro-SM models and the accurate data are less than 1%, demonstrating that the accurcy of the proposed method is higher than those of the existing models.

  2. Doping-less Tunnel Field Effect Transistor: Design and Investigation

    OpenAIRE

    Kumar, M. Jagadesh; Janardhanan, Sindhu

    2013-01-01

    Using calibrated simulations, we report a detailed study of the doping-less tunnel field effect transistor (TFET) on a thin intrinsic silicon film using charge plasma concept. Without the need for any doping, the source and drain regions are formed using the charge plasma concept by choosing appropriate work functions for the source and drain metal electrodes. Our results show that the performance of the doping-less TFET is similar to that of a corresponding doped TFET. The doping-less TFET i...

  3. Dynamics of Bloch oscillating transistor near bifurcation threshold

    OpenAIRE

    Sarkar, Jayanta; Puska, Antti; Hassel, Juha; Hakonen, Pertti J.

    2013-01-01

    Tendency to bifurcate can often be utilized to improve performance characteristics of amplifiers or even to build detectors. Bloch oscillating transistor is such a device. Here we show that bistable behaviour can be approached by tuning the base current and that the critical value depends on the Josephson coupling energy $E_J$ of the device. We demonstrate record-large current gains for device operation near the bifurcation point at small $E_J$. From our results for the current gains at vario...

  4. MoS2 nanotube field effect transistors

    OpenAIRE

    M. Strojnik; A. Kovic; Mrzel, A; J. Buh; Strle, J.; Mihailovic, D.

    2014-01-01

    We report on electric field effects on electron transport in multi-walled MoS2 nanotubes (NTs), fabricated using a two-step synthesis method from Mo6SxI9-x nanowire bundle precursors. Transport properties were measured on 20 single nanotube field effect transistor (FET) devices, and compared with MoS2 layered crystal devices prepared using identical fabrication techniques. The NTs exhibited mobilities of up to 0.014 cm2V−1s−1 and an on/off ratio of up to 60. As such they are comparable with p...

  5. Organic electrochemical transistors based on a dielectrophoretically aligned nanowire array

    Directory of Open Access Journals (Sweden)

    Choi WooSeok

    2011-01-01

    Full Text Available Abstract In this study, we synthesized an organic electrochemical transistor (OECT using dielectrophoresis of a carbon nanotube-Nafion (CNT-Nafion suspension. Dielectrophoretically aligned nanowires formed a one-dimensional submicron bundle between triangular electrodes. The CNT-Nafion composite nanowire bundles showed p-type semiconductor characteristics. The drain-source current decreased with increasing gate voltage. The nanowire bundles showed potential as pH sensor because the drain-source current ratio varied linearly according to the gate voltage in pH buffers.

  6. A light-emitting field-effect transistor

    International Nuclear Information System (INIS)

    The structure and operating characteristics of an ambipolar light-emitting field-effect transistor based on single crystals of the organic semiconductors α-sexithiophene were reported. Electrons and holes are injected from the source and drain electrodes, respectively. Their concentrations are controlled by the applied gate and drain-source voltages. Excitons are generated, leading to radiative recombination. Moreover, above a remarkably low threshold current, coherent light is emitted through amplified spontaneous emission. Hence, this three-terminal device is the basis of a very promising architecture for electrically driven laser action in organic semiconductors. (authors)

  7. Ferroelectric memory element based on thin film field effect transistor

    Science.gov (United States)

    Poghosyan, A. R.; Aghamalyan, N. R.; Elbakyan, E. Y.; Guo, R.; Hovsepyan, R. K.

    2013-09-01

    We report the preparation and investigation of ferroelectric field effect transistors (FET) using ZnO:Li films with high field mobility of the charge carriers as a FET channel and as a ferroelectric active element simultaneously. The possibility for using of ferroelectric FET based on the ZnO:Li films in the ZnO:Li/LaB6 heterostructure as a bi-stable memory element for information recording is shown. The proposed ferroelectric memory structure does not manifest a fatigue after multiple readout of once recorded information.

  8. Direct growth of nanocrystalline diamond field-effect transistor microstructures

    Czech Academy of Sciences Publication Activity Database

    Kozak, Halyna; Kromka, Alexander; Michalíková, Lenka; Rezek, Bohuslav

    Warrendale, PA: MRS , 2009. s. 23-23. ISBN N. [E- MRS 2009 Spring Meeting. 08.06.2009-12.06.2009, Strasbourg] R&D Projects: GA MŠk LC510; GA MŠk(CZ) LC06040; GA AV ČR KAN400100701; GA AV ČR(CZ) IAAX00100902 Institutional research plan: CEZ:AV0Z10100521 Keywords : nanocrystalline diamond * microstructures * atomic force microscopy * surface conductivity * field-effect transistor Subject RIV: BM - Solid Matter Physics ; Magnetism

  9. Ultra-short suspended single-wall carbon nanotube transistors

    OpenAIRE

    Island, J. O.; Tayari, V.; Yigen, S.; McRae, A. C.; Champagne, A. R.

    2011-01-01

    We describe a method to fabricate clean suspended single-wall carbon nanotube (SWCNT) transistors hosting a single quantum dot ranging in length from a few 10s of nm down to $\\approx$ 3 nm. We first align narrow gold bow-tie junctions on top of individual SWCNTs and suspend the devices. We then use a feedback-controlled electromigration to break the gold junctions and expose nm-sized sections of SWCNTs. We measure electron transport in these devices at low temperature and show that they form ...

  10. Directly grown nanocrystalline diamond field-effect transistor microstructures

    Czech Academy of Sciences Publication Activity Database

    Kozak, Halyna; Kromka, Alexander; Babchenko, Oleg; Rezek, Bohuslav

    2010-01-01

    Roč. 8, č. 3 (2010), s. 482-487. ISSN 1546-198X R&D Projects: GA MŠk(CZ) LC06040; GA AV ČR KAN400100701; GA MŠk LC510; GA AV ČR(CZ) IAAX00100902; GA AV ČR KAN400100652 Institutional research plan: CEZ:AV0Z10100521 Keywords : nanocrystalline diamond * microstructures * atomic force microscopy * surface conductivity * field-effect transistor Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.602, year: 2010

  11. The design and fabrication on gate type resonant tunneling transistor

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In light of fabricating resonant tunneling diode(RTD),in this paper a GaAs-based resonant tunneling transistor with gate structure(GRTT)has been designed and fabricated successfully.A systematic depiction centers on the designs of material structure,device structure,photo lithography mask,fabrication of device and the measurement and analysis of parameters.The fabricated GRTT has a maximum PVCR of 46 and a maximum transconductance of 8 mS.The work lays the foundation for further improvement on the performance and parameters of RTT.

  12. Intrinsic magnetic refrigeration of a single electron transistor

    Energy Technology Data Exchange (ETDEWEB)

    Ciccarelli, C.; Ferguson, A. J. [Cavendish Laboratory, University of Cambridge, Cambridge CB3 0HE (United Kingdom); Campion, R. P.; Gallagher, B. L. [School of Physics and Astronomy, University of Nottingham, Nottingham NG7 2RD (United Kingdom)

    2016-02-01

    In this work, we show that aluminium doped with low concentrations of magnetic impurities can be used to fabricate quantum devices with intrinsic cooling capabilities. We fabricate single electron transistors made of aluminium doped with 2% Mn by using a standard multi angle evaporation technique and show that the quantity of metal used to fabricate the devices generates enough cooling power to achieve a drop of 160 mK in the electron temperature at the base temperature of our cryostat (300 mK). The cooling mechanism is based on the magneto-caloric effect from the diluted Mn moments.

  13. Characterization of a Common-Gate Amplifier Using Ferroelectric Transistors

    Science.gov (United States)

    Hunt, Mitchell; Sayyah, Rana; MacLeod, Todd C.; Ho, Fat D.

    2011-01-01

    In this paper, the empirical data collected through experiments performed using a FeFET in the common-gate amplifier circuit is presented. The FeFET common-gate amplifier was characterized by varying all parameters in the circuit, such as load resistance, biasing of the transistor, and input voltages. Due to the polarization of the ferroelectric layer, the particular behavior of the FeFET common-gate amplifier presents interesting results. Furthermore, the differences between a FeFET common-gate amplifier and a MOSFET common-gate amplifier are examined.

  14. Transistor Devices 7kW AC/DC电源

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Transistor Devices公司推出LCPM系列7kW液体冷却电源模块,每个模块的尺寸为2″×2.8×″(11.6W每立方英寸),因此六个并排置于17.5″架子上的模块可以自平衡的3相国际电源(195V AC至265V AC-47-63周期)传递达42kW的稳定电源。

  15. Ambipolar transistors based on random networks of WS2 nanotubes

    Science.gov (United States)

    Sugahara, Mitsunari; Kawai, Hideki; Yomogida, Yohei; Maniwa, Yutaka; Okada, Susumu; Yanagi, Kazuhiro

    2016-07-01

    WS2 nanotubes are rolled multiwalled nanotubes made of a layered material, tungsten disulfide. Their fibril structures enable the fabrication of random network films; however, these films are nonconducting, and thus have not been used for electronic applications. Here, we demonstrate that carrier injection into WS2 networks using an electrolyte gating approach could cause these networks to act as semiconducting channels. We clarify the Raman characteristics of WS2 nanotubes under electrolyte gating and confirm the feasibility of the injection of electrons and holes. We reveal ambipolar behaviors of the WS2 nanotube networks in field-effect transistor setups with electrolyte gating.

  16. Cryogenically Cooled Field Effect Transistors for Low-Noise Systems

    Science.gov (United States)

    Wollack, Edward J.

    2002-01-01

    Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

  17. Cryogenetically Cooled Field Effect Transistors for Low-Noise Systems

    Science.gov (United States)

    Wollack, Edward J.; Rabin, Douglas M. (Technical Monitor)

    2002-01-01

    Recent tends in the design, fabrication and use of High-Electron-Mobility-Transistors (HEMT) in low noise amplifiers are reviewed. Systems employing these devices have achieved the lowest system noise for wavelengths greater than three millimeters with relatively modest cryogenic cooling requirements in a variety of ground and space based applications. System requirements which arise in employing such devices in imaging applications are contrasted with other leading coherent detector candidates at microwave wavelengths. Fundamental and practical limitations which arise in the context of microwave application of field effect devices at cryogenic temperatures will be discussed from a component and systems point of view.

  18. Single-event burnout of power bipolar junction transistors

    International Nuclear Information System (INIS)

    Experimental evidence of single-event burnout of power bipolar junctions transistors (BJTs) is reported for the first time. Several commercial power BJTs were characterized in a simulated cosmic ray environment using mono-energetic ions at the tandem Van de Graaff accelerator facility at Brookhaven National Laboratory. Most of the device types exposed to this simulated environment exhibited burnout behavior. In this paper the experimental technique, data, and results are presented, while a qualitative model is used to help explain those results and trends observed in this experiment

  19. Nano-Transistor Modeling: Two Dimensional Green's Function Method

    Science.gov (United States)

    Svizhenko, Alexei; Anantram, M. P.; Govindan, T. R.; Biegel, Bryan

    2001-01-01

    Two quantum mechanical effects that impact the operation of nanoscale transistors are inversion layer energy quantization and ballistic transport. While the qualitative effects of these features are reasonably understood, a comprehensive study of device physics in two dimensions is lacking. Our work addresses this shortcoming and provides: (a) a framework to quantitatively explore device physics issues such as the source-drain and gate leakage currents, DIBL (Drain Induced Barrier Lowering), and threshold voltage shift due to quantization, and b) a means of benchmarking quantum corrections to semiclassical models (such as density-gradient and quantum-corrected MEDICI).

  20. Electrolyte-gated organic synapse transistor interfaced with neurons

    CERN Document Server

    Desbief, Simon; Casalini, Stefano; Guerin, David; Tortorella, Silvia; Barbalinardo, Marianna; Kyndiah, Adrica; Murgia, Mauro; Cramer, Tobias; Biscarini, Fabio; Vuillaume, Dominique

    2016-01-01

    We demonstrate an electrolyte-gated hybrid nanoparticle/organic synapstor (synapse-transistor, termed EGOS) that exhibits short-term plasticity as biological synapses. The response of EGOS makes it suitable to be interfaced with neurons: short-term plasticity is observed at spike voltage as low as 50 mV (in a par with the amplitude of action potential in neurons) and with a typical response time in the range of tens milliseconds. Human neuroblastoma stem cells are adhered and differentiated into neurons on top of EGOS. We observe that the presence of the cells does not alter short-term plasticity of the device.

  1. Noise in ZnO nanowire field effect transistors.

    Science.gov (United States)

    Xiong, Hao D; Wang, Wenyong; Suehle, John S; Richter, Curt A; Hong, Woong-Ki; Lee, Takhee

    2009-02-01

    The noise power spectra in ZnO nanowire field effect transistors (FETs) were experimentally investigated and showed a classical 1/f dependence. A Hooge's constant of 5 x 10(-3) was estimated. This value is within the range reported for CMOS FETs with high-k dielectrics, supporting the concept that nanowires can be utilized for future beyond-CMOS electronic applications from the point of view of device noise properties. ZnO FETs measured in a dry O2 environment displayed elevated noise levels compared to in vacuum. At low temperature, random telegraph signals are observed in the drain current. PMID:19441450

  2. Evolutionary Multiobjective Design Targeting a Field Programmable Transistor Array

    Science.gov (United States)

    Aguirre, Arturo Hernandez; Zebulum, Ricardo S.; Coello, Carlos Coello

    2004-01-01

    This paper introduces the ISPAES algorithm for circuit design targeting a Field Programmable Transistor Array (FPTA). The use of evolutionary algorithms is common in circuit design problems, where a single fitness function drives the evolution process. Frequently, the design problem is subject to several goals or operating constraints, thus, designing a suitable fitness function catching all requirements becomes an issue. Such a problem is amenable for multi-objective optimization, however, evolutionary algorithms lack an inherent mechanism for constraint handling. This paper introduces ISPAES, an evolutionary optimization algorithm enhanced with a constraint handling technique. Several design problems targeting a FPTA show the potential of our approach.

  3. Bottom-up graphene nanoribbon field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, Patrick B. [Applied Science and Technology, University of California, Berkeley, California 94720 (United States); Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Pedramrazi, Zahra [Department of Physics, University of California, Berkeley, California 94720 (United States); Madani, Ali [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Chen, Yen-Chia; Crommie, Michael F. [Department of Physics, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720 (United States); Oteyza, Dimas G. de [Department of Physics, University of California, Berkeley, California 94720 (United States); Centro de Física de Materiales CSIC/UPV-EHU-Materials Physics Center, San Sebastián E-20018 (Spain); Chen, Chen [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Fischer, Felix R. [Department of Chemistry, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720 (United States); Bokor, Jeffrey, E-mail: jbokor@eecs.berkeley.edu [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, California 94720 (United States); Materials Sciences Division, Lawrence Berkeley National Laboratories, Berkeley, California 94720 (United States)

    2013-12-16

    Recently developed processes have enabled bottom-up chemical synthesis of graphene nanoribbons (GNRs) with precise atomic structure. These GNRs are ideal candidates for electronic devices because of their uniformity, extremely narrow width below 1 nm, atomically perfect edge structure, and desirable electronic properties. Here, we demonstrate nano-scale chemically synthesized GNR field-effect transistors, made possible by development of a reliable layer transfer process. We observe strong environmental sensitivity and unique transport behavior characteristic of sub-1 nm width GNRs.

  4. High frequency microbubble-switched oscillations modulated by microfluidic transistors

    Science.gov (United States)

    Yang, Fanghao; Dai, Xianming; Li, Chen

    2012-08-01

    Creating high frequency two-phase oscillations (HF-TPOs) remains an important goal in advancing microscale fluidic logic devices, micro-mixers, micro-actuators, and flow controls. However, thermally driven TPO frequency has been hindered by confinements of compressible vapor bubbles and low thermal diffusivity in microfluidic systems. In this study, a mechanism creating high frequency microbubbles growth/collapse cycle has been developed to achieve HF-TPOs. A "microfluidic transistor" was conceptualized and fabricated to passively sustain and modulate HF-TPOs. Three orders of magnitude higher TPO frequency has been achieved compared to TPOs reported in literatures under similar working conditions.

  5. Three-Dimensional Insulated Gate Bipolar Transistor (IGBT) Development

    OpenAIRE

    Gilbert, P.V.; Neudeck, G. W.

    1992-01-01

    A new insulated gate bipolar transistor structure, the 3D-IGBT, is presented. The 3D-IGBT utilizes selective epitaxial silicon to form a top contacted anode and still retain the cellular structure of vemcally oriented devices. The 3D-IGBT , unlike other fully integrable power devices, exploits the merits of cellular structure to increase its packing density and thus reduce its on-resistance per unit area. It also eliminates the parasitic JFET resistance found in vertical IGBT's. To integrate ...

  6. Characteristics of voltage regulators with serial NPN transistor in the fields of medium and high energy photons

    International Nuclear Information System (INIS)

    Variation of collector - emitter dropout voltage on serial transistors of voltage regulators LM2990T-5 and LT1086CT5 were used as the parameter for detection of examined devices' radiation hardness in X and ? radiation fields. Biased voltage regulators with serial super-β transistor in the medium dose rate X radiation field had significantly different response from devices with conventional serial NPN transistor. Although unbiased components suffered greater damage in most cases, complete device failure happened only among the biased components with serial super-β transistor in Bremsstrahlung field. Mechanisms of transistors degradation in ionizing radiation fields were analysed

  7. The Bipolar Field-Effect Transistor: ⅩⅢ. Physical Realizations of the Transistor and Circuits (One-Two-MOS-Gates on Thin-Thick Pure-Impure Base)

    Institute of Scientific and Technical Information of China (English)

    薩支唐; 揭斌斌

    2009-01-01

    This paper reports the physical realization of the Bipolar Field-Effect Transistor (BiFET) and its one-transistor basic building block circuits. Examples are given for the one and two MOS gates on thin and thick, pure and impure base, with electron and hole contacts, and the corresponding theoretical current-voltage characteristics previously computed by us, without generation-recombination-trapping-tunneling of electrons and holes. These ex-amples include the one-MOS-gate on semi-infinite thick impure base transistor (the bulk transistor) and the impure-thin-base Silicon-on-Insulator (SOI) transistor and the two-MOS-gates on thin base transistors (the FinFET and the Thin Film Transistor TFT). Figures are given with the cross-section views containing the electron and hole concen-tration and current density distributions and trajectories and the corresponding DC current-voltage characteristics.

  8. Temperature Dependence of Field-Effect Mobility in Organic Thin-Film Transistors: Similarity to Inorganic Transistors.

    Science.gov (United States)

    Okada, Jun; Nagase, Takashi; Kobayashi, Takashi; Naito, Hiroyoshi

    2016-04-01

    Carrier transport in solution-processed organic thin-film transistors (OTFTs) based on dioctylbenzothienobenzothiophene (C8-BTBT) has been investigated in a wide temperature range from 296 to 10 K. The field-effect mobility shows thermally activated behavior whose activation energy becomes smaller with decreasing temperature. The temperature dependence of field-effect mobility found in C8-BTBT is similar to that of others materials: organic semiconducting polymers, amorphous oxide semiconductors and hydrogenated amorphous silicon. These results indicate that hopping transport between isoenergetic localized states becomes dominated in a low temperature regime in these materials. PMID:27451607

  9. Flexible graphene transistors for recording cell action potentials

    Science.gov (United States)

    Blaschke, Benno M.; Lottner, Martin; Drieschner, Simon; Bonaccini Calia, Andrea; Stoiber, Karolina; Rousseau, Lionel; Lissourges, Gaëlle; Garrido, Jose A.

    2016-06-01

    Graphene solution-gated field-effect transistors (SGFETs) are a promising platform for the recording of cell action potentials due to the intrinsic high signal amplification of graphene transistors. In addition, graphene technology fulfills important key requirements for in-vivo applications, such as biocompability, mechanical flexibility, as well as ease of high density integration. In this paper we demonstrate the fabrication of flexible arrays of graphene SGFETs on polyimide, a biocompatible polymeric substrate. We investigate the transistor’s transconductance and intrinsic electronic noise which are key parameters for the device sensitivity, confirming that the obtained values are comparable to those of rigid graphene SGFETs. Furthermore, we show that the devices do not degrade during repeated bending and the transconductance, governed by the electronic properties of graphene, is unaffected by bending. After cell culture, we demonstrate the recording of cell action potentials from cardiomyocyte-like cells with a high signal-to-noise ratio that is higher or comparable to competing state of the art technologies. Our results highlight the great capabilities of flexible graphene SGFETs in bioelectronics, providing a solid foundation for in-vivo experiments and, eventually, for graphene-based neuroprosthetics.

  10. All-electric spin transistor using perpendicular spins

    Science.gov (United States)

    Kim, Ji Hoon; Bae, Joohyung; Min, Byoung-Chul; Kim, Hyung-jun; Chang, Joonyeon; Koo, Hyun Cheol

    2016-04-01

    All-electric spin transistor is demonstrated using perpendicular spins in an InAs quantum well channel. For the injection and detection of perpendicular spins in the quantum well channel, we use Tb20Fe62Co18/Co40Fe40B20 electrodes, where the Tb20Fe62Co18 layer produces the perpendicular magnetization and the Co40Fe40B20 layer enhances the spin polarization. In this spin transistor device, a gate-controlled spin signal as large as 80 mΩ is observed at 10 K without an external magnetic field. In order to confirm the spin injection and relaxation independently, we measure the three-terminal Hanle effect with an in-plane magnetic field, and obtain a spin signal of 1.7 mΩ at 10 K. These results clearly present that the electric field is an efficient way to modulate spin orientation in a strong spin-orbit interaction system.

  11. Development of solution-gated graphene transistor model for biosensors.

    Science.gov (United States)

    Karimi, Hediyeh; Yusof, Rubiyah; Rahmani, Rasoul; Hosseinpour, Hoda; Ahmadi, Mohammad T

    2014-01-01

    : The distinctive properties of graphene, characterized by its high carrier mobility and biocompatibility, have stimulated extreme scientific interest as a promising nanomaterial for future nanoelectronic applications. In particular, graphene-based transistors have been developed rapidly and are considered as an option for DNA sensing applications. Recent findings in the field of DNA biosensors have led to a renewed interest in the identification of genetic risk factors associated with complex human diseases for diagnosis of cancers or hereditary diseases. In this paper, an analytical model of graphene-based solution gated field effect transistors (SGFET) is proposed to constitute an important step towards development of DNA biosensors with high sensitivity and selectivity. Inspired by this fact, a novel strategy for a DNA sensor model with capability of single-nucleotide polymorphism detection is proposed and extensively explained. First of all, graphene-based DNA sensor model is optimized using particle swarm optimization algorithm. Based on the sensing mechanism of DNA sensors, detective parameters (Ids and Vgmin) are suggested to facilitate the decision making process. Finally, the behaviour of graphene-based SGFET is predicted in the presence of single-nucleotide polymorphism with an accuracy of more than 98% which guarantees the reliability of the optimized model for any application of the graphene-based DNA sensor. It is expected to achieve the rapid, quick and economical detection of DNA hybridization which could speed up the realization of the next generation of the homecare sensor system. PMID:24517158

  12. Polymer transistors fabricated by painting of metallic nanoparticles

    Science.gov (United States)

    Li, S. P.; Russell, D. M.; Newsome, C. J.; Kugler, T.; Shimoda, T.

    2006-09-01

    In this letter the authors describe the fabrication of high performance polymer thin film transistors using an aqueous based silver colloid to form source and drain electrodes patterned by brush painting. The electrode dimensions were controlled by a surface energy pattern defined by soft contact printing of a self-assembled monolayer 1H,1H,2H,2H-perfluorodecyl-trichlorosilane on a SiO2 surface which acted as a dewetting layer for the painted silver particle suspension. Another self-assembled monolayer of 1H ,1H,2H,2H-perfluorodecanethiol was also used to increase the work function of the patterned silver electrodes in order to decrease the barrier for charge injection into the polymer semiconductor. The field-effect mobility of the thin film transistors fabricated by this method approached 0.02cm2V-1s-1 with an on/off current ratio of 105. The relative high mobility may be influenced by the ordering of the poly(3-hexylthiophene) semiconductor layer by the self-assembled monolayer used to define the source and drain electrodes.

  13. Optimization of ultra-low-power CMOS transistors

    CERN Document Server

    Stockinger, M

    2000-01-01

    chosen suitable for ultra-low-power purposes. In a first optimization study the drive current of NMOS transistors is maximized while keeping the leakage current below a limit of 1 pA/mu m. This results in peaking channel doping devices (PCD) with narrow doping peaks placed asymmetrically in the channel. Drive current improvements of 45 % and 71 % for the 0.25 mu m and 0.1 mu m devices, respectively, are achieved compared to uniformly doped devices. The PCD device is studied in detail and explanations for its superior drive performance are given. It is compared to already known device structures and practical alternatives are suggested with respect to its manufacturability. In a second optimization study the gate delay times of complete CMOS inverters are minimized. Both the doping profiles of the NMOS and PMOS transistors are optimized at the same time which results again in PCD devices. The inverter speeds are improved by 54 % and 97 % for the 0.25 mu m and 0.1 mu m devices, respectively. Ultra-low-power CMO...

  14. Introduction to thin film transistors physics and technology of TFTs

    CERN Document Server

    Brotherton, S D

    2013-01-01

    Introduction to Thin Film Transistors reviews the operation, application, and technology of the main classes of thin film transistor (TFT) of current interest for large area electronics. The TFT materials covered include hydrogenated amorphous silicon (a-Si:H), poly-crystalline silicon (poly-Si), transparent amorphous oxide semiconductors (AOS), and organic semiconductors. The large scale manufacturing of a-Si:H TFTs forms the basis of the active matrix flat panel display industry. Poly-Si TFTs facilitate the integration of electronic circuits into portable active matrix liquid crystal displays, and are increasingly used in active matrix organic light emitting diode (AMOLED) displays for smart phones. The recently developed AOS TFTs are seen as an alternative option to poly-Si and a-Si:H for AMOLED TV and large AMLCD TV applications, respectively. The organic TFTs are regarded as a cost effective route into flexible electronics. As well as treating the highly divergent preparation and properties of these mat...

  15. Carbon nanotube transistor based high-frequency electronics

    Science.gov (United States)

    Schroter, Michael

    At the nanoscale carbon nanotubes (CNTs) have higher carrier mobility and carrier velocity than most incumbent semiconductors. Thus CNT based field-effect transistors (FETs) are being considered as strong candidates for replacing existing MOSFETs in digital applications. In addition, the predicted high intrinsic transit frequency and the more recent finding of ways to achieve highly linear transfer characteristics have inspired investigations on analog high-frequency (HF) applications. High linearity is extremely valuable for an energy efficient usage of the frequency spectrum, particularly in mobile communications. Compared to digital applications, the much more relaxed constraints for CNT placement and lithography combined with already achieved operating frequencies of at least 10 GHz for fabricated devices make an early entry in the low GHz HF market more feasible than in large-scale digital circuits. Such a market entry would be extremely beneficial for funding the development of production CNTFET based process technology. This talk will provide an overview on the present status and feasibility of HF CNTFET technology will be given from an engineering point of view, including device modeling, experimental results, and existing roadblocks. Carbon nanotube transistor based high-frequency electronics.

  16. `Soft' amplifier circuits based on field-effect ionic transistors

    Science.gov (United States)

    Boon, Niels; Olvera de La Cruz, Monica

    Soft materials can be used as building blocks of electronic devices with extraordinary properties. We demonstrate that an ionic analogue of the semiconductor field-effect transistor (FET) could be used for voltage and current amplifiers. Our theoretical model incorporates readily-available soft materials, such as conductive porous membranes and polymer electrolytes to represent a current-gating device that can be integrated in electronic circuits. By means of Nernst-Planck numerical simulations as well as an analytical approach towards expressions that describe steady-state currents, we find that the behavior in response to various input voltages can be categorized into ohmic, sub-threshold, and active modes. This is fully analogous to what is known for semiconductor FETs. Pivotal FET properties such as threshold voltage and transconductance must be related to half-cell redox potentials as well as polyelectrolyte and gate material properties. We further extend the analogy with semiconductor FETs through numerical simulations of elementary amplifier circuits in which we successfully substitute the semiconductor transistor by an ionic FET.

  17. Nano-textured high sensitivity ion sensitive field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Hajmirzaheydarali, M.; Sadeghipari, M.; Akbari, M.; Shahsafi, A.; Mohajerzadeh, S., E-mail: mohajer@ut.ac.ir [Thin Film and Nanoelectronics Lab, Nanoelectronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran, Tehran 143957131 (Iran, Islamic Republic of)

    2016-02-07

    Nano-textured gate engineered ion sensitive field effect transistors (ISFETs), suitable for high sensitivity pH sensors, have been realized. Utilizing a mask-less deep reactive ion etching results in ultra-fine poly-Si features on the gate of ISFET devices where spacing of the order of 10 nm and less is achieved. Incorporation of these nano-sized features on the gate is responsible for high sensitivities up to 400 mV/pH in contrast to conventional planar structures. The fabrication process for this transistor is inexpensive, and it is fully compatible with standard complementary metal oxide semiconductor fabrication procedure. A theoretical modeling has also been presented to predict the extension of the diffuse layer into the electrolyte solution for highly featured structures and to correlate this extension with the high sensitivity of the device. The observed ultra-fine features by means of scanning electron microscopy and transmission electron microscopy tools corroborate the theoretical prediction.

  18. Third-order intermodulation distortion in graphene resonant channel transistors

    Science.gov (United States)

    Lekas, Michael; Lee, Sunwoo; Cha, Wujoon; Hone, James; Shepard, Kenneth

    2015-02-01

    Third-order intermodulation distortion (IM3) is an important metric for electromechanical resonators used in radio frequency signal processing applications since it characterizes the nonlinearity of the device, and the amount of in-band interference it generates when subject to unwanted, out-of-band signals. In this letter, we measure and model IM3 in a strain-engineered graphene mechanical resonator operated as a graphene resonant channel transistor (G-RCT). The device analyzed in this work has a voltage third-order intercept point (VIIP3) of 69.5 dBm V at a gate-to-source DC bias (Vgs) of 2.5 V, which drops to 52.1 dBm V at Vgs = 4.5 V when driven with two out-of-band input tones spaced 5 and 10 MHz from the resonant frequency. The decrease in the VIIP3 with Vgs coincides with an increase in the transmission response (S21) of the device, illustrating a trade-off between transduction efficiency and linearity. In addition, we find that conventional micro-electro-mechanical systems theory for IM3 calculation does not accurately describe our measurement data. To resolve this discrepancy, we develop a model for IM3 in G-RCTs that takes into account all of the output current terms present in the embedded transistor structure, as well as an effective Duffing parameter (αeff).

  19. Silicon junctionless field effect transistors as room temperature terahertz detectors

    International Nuclear Information System (INIS)

    Terahertz (THz) radiation detection by junctionless metal-oxide-semiconductor field-effect transistors (JL MOSFETs) was studied and compared with THz detection using conventional MOSFETs. It has been shown that in contrast to the behavior of standard transistors, the junctionless devices have a significant responsivity also in the open channel (low resistance) state. The responsivity for a photolithographically defined JL FET was 70 V/W and the noise equivalent power 460 pW/√Hz. Working in the open channel state may be advantageous for THz wireless and imaging applications because of its low thermal noise and possible high operating speed or large bandwidth. It has been proven that the junctionless MOSFETs can also operate in a zero gate bias mode, which enables simplification of the THz array circuitry. Existing models of THz detection by MOSFETs were considered and it has been demonstrated that the process of detection by these junctionless devices cannot be explained within the framework of the commonly accepted models and therefore requires a new theoretical approach

  20. Nano-textured high sensitivity ion sensitive field effect transistors

    International Nuclear Information System (INIS)

    Nano-textured gate engineered ion sensitive field effect transistors (ISFETs), suitable for high sensitivity pH sensors, have been realized. Utilizing a mask-less deep reactive ion etching results in ultra-fine poly-Si features on the gate of ISFET devices where spacing of the order of 10 nm and less is achieved. Incorporation of these nano-sized features on the gate is responsible for high sensitivities up to 400 mV/pH in contrast to conventional planar structures. The fabrication process for this transistor is inexpensive, and it is fully compatible with standard complementary metal oxide semiconductor fabrication procedure. A theoretical modeling has also been presented to predict the extension of the diffuse layer into the electrolyte solution for highly featured structures and to correlate this extension with the high sensitivity of the device. The observed ultra-fine features by means of scanning electron microscopy and transmission electron microscopy tools corroborate the theoretical prediction