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ABSTRACT: RF characterization of epitaxial graphene nano ribbon field-effect transistor (GNRFET) was investigated. The few layers graphene were synthesized by thermal decomposition of {0001} silicon carbide under UHV environment. Raman spectroscopy, AFM and Hall measurement were used to investigate the properties of graphene synthesized. Despite the Hall mobility was lower than 500 cm<sup>2</sup>/Vs, the intrinsic current gain cut-off frequency of 60 GHz and maximum oscillation frequency of 30 GHz were obtained. This work shows the strong potentiality of GNRFET in future high speed electronics.
Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International; 07/2011
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ABSTRACT: The static and dynamic characteristics of top-gated graphene nanoribbon-based field-effect transistors were investigated. Multilayer graphene was synthesized by thermal decomposition of Si-face silicon carbide. The impact of the number of graphene layers on device performance was explored. It was found that, with the reduction of the layer number from ten to five, a significant improvement of direct-current characteristics and high-frequency performance can be observed. A high intrinsic current-gain cutoff frequency of 60 GHz and a maximum oscillation frequency of 28 GHz are reported.
IEEE Transactions on Electron Devices 07/2011; · 2.32 Impact Factor
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ABSTRACT: High frequency characterization of epitaxial-grown graphene nano ribbon based field-effect transistor (GNRFET) was investigated. The few layers graphene were synthesized by thermal decomposition of Si-faced silicon carbide. The intrinsic current gain cut-off frequency of 10 GHz was obtained. A small signal equivalent circuit model of this device was proposed which open a potentiality to the modelling of GNR based HF electronics.
Microwave Integrated Circuits Conference (EuMIC), 2010 European; 10/2010
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ABSTRACT: We have fabricated an original graphene field effect transistor (FET) on silicon carbide (SiC) substrate. Based on an array of parallel graphene nano ribbons (GNRs), these devices are well suited for high frequency (HF) applications. Exploration of HF performance shows at room temperature intrinsic current gain cut-off frequency if) of 10 GHz and maximum oscillation frequency (f<sub>max</sub>) of 6 GHz. At 77 K, we find out that these HF performance are improved by about 50% (f<sub>t</sub> and f<sub>max</sub> are respectively 15 GHz and 10 GHz). These results show the strong dependence of temperature on device performance.
Device Research Conference (DRC), 2010; 07/2010
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ABSTRACT: Carbon nanotubes are intrinsically high impedance objects. The high frequency (HF) characterization of these nano-objects is crucial for applications such as interconnects in future integrated circuits, but still represents a daunting challenge. This letter presents HF characterization of an individual metallic single walled carbon nanotube up to 7 GHz. The equivalent circuit values are directly extracted from these HF measurements without numerical procedure, thus proving that the intrinsic transport parameters of a single carbon nanotube can be determined up to gigahertz frequencies.
Applied Physics Letters 01/2010; 96(4):042109-042109-3. · 3.84 Impact Factor
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ABSTRACT: This paper presents the high frequency performance of single-walled carbon nanotube (SWNT) field-effect transistors, with channel consisting of dense networks of high purity semiconducting SWNTs. Using SWNT samples containing 99% pure semiconducting SWNTs, we achieved operating frequencies above 80 GHz. This record frequency does not require aligned SWNTs, thus demonstrating the remarkable potential of random networks of sorted SWNTs for high frequency electronics.
Applied Physics Letters 06/2009; 94(24):243505-243505-3. · 3.84 Impact Factor
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ABSTRACT: We report for the first time to our knowledge large-signal measurements performed at 600 MHz and in time domain on carbon nanotube field-effect transistors (CNFETs) using a large-signal network analyzer. To overcome the very high mismatch between the high CNFET impedance and the basic 50-Omega configuration of the setup, the output impedance was matched with the help of an experimental active load-pull configuration. Hence, we were able to observe under large-signal conditions the nonlinear behavior of CNFETs. Static measurements and continuous-wave S <sub>ij</sub> -parameter measurements were made for many different biases. They were used in order to determine a nonlinear electrical model that has been validated thanks to the nonlinear measurements. The developed model opens the way for electrical CNFET circuit simulation and nonlinear applications of these devices.
IEEE Transactions on Microwave Theory and Techniques 08/2008; · 1.85 Impact Factor
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ABSTRACT: Carbon Nanotube Field Effect Transistors (CN- FETs) seem to be very promising candidates for the future microwave frequency applications. However, these components present high impedance values which make very difficult the characterization using usual characteristic impedance of microwave instrumentations (50Omega). To determine CNFET microwave capabilities, special techniques of measurements must be developed such as for example heterodyne detection, or two-tone measurements with the observation of the inter- modulation products. In our case we propose an original method using a Large Signal Network Analyser (LSNA) associated with an active load pull configuration. The aim of this active load pull is to reduce the mismatch between the CNFET output impedance and the 50Omega load and hence increase the measurements accuracy of these nano- devices. Moreover these samples can be characterize in linear but also non linear conditions.
Microwave Symposium Digest, 2008 IEEE MTT-S International; 07/2008
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ABSTRACT: We report on microwave operation of top-gated single carbon nanotube transistors. From transmission measurements in the 0.1-1.6 GHz range, we deduce device transconductance gm and gate-nanotube capacitance Cg of micro- and nanometric devices. A large and frequency-independent gm approximately 20 microS is observed on short devices, which meets the best dc results. The capacitance per unit gate length of 60 aF/microm is typical of top gates on a conventional oxide with epsilon approximately 10. This value is a factor of 3-5 below the nanotube quantum capacitance which, according to recent simulations, favors high transit frequencies fT=gm/2piCg. For our smallest devices, we find a large fT approximately 50 GHz with no evidence of saturation in length dependence.
Nano Letters 03/2008; 8(2):525-8. · 13.20 Impact Factor
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ABSTRACT: 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 6 GHz and a current gain cutoff frequency (fT) as high as 1 GHz at VDS = −700 mV. 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 3.3 mm.
Applied Physics Letters 10/2007; 91(15):153111-153111-3. · 3.84 Impact Factor
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ABSTRACT: High frequency capabilities of carbon nanotube field-effect transistors (CNTFETs) are investigated. Structures with a large number of single-walled carbon nanotubes were fabricated using dielecrophoresis to increase the density of nanotubes in the device channel. The authors obtained an intrinsic current gain cutoff frequency of 30 GHz establishing state-of-the-art high frequency (hf) potentialities of CNTFETs. The device also showed a maximum stable gain above 10 dB at 20 GHz. Finally, the parameters of an equivalent circuit model of multitube CNTFET at 20 GHz are determined, which open the route to the modeling of nanotubes-based hf electronics.
Applied Physics Letters 06/2007; 90(23):233108-233108-3. · 3.84 Impact Factor
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J.P. Bourgoin,
J. Borghetti,
P. Chenevier,
V. Derycke,
A. Filoramo,
L. Goux,
M. F. Goffman,
S. Lyonnais,
K. Nguyen,
G. Robert,
S. Streiff,
J.M. Bethoux, H. Happy,
G. Dambrine,
S. Lenfant,
D. Vuillaume
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ABSTRACT: Chemically and biochemically-directed assembly of nanotubes (NT) for electronics is reviewed. Examples of new field-effect devices prepared this way either for high frequency (40GHz) operation or for applications to an optoelectronics multilevel memory are presented. A route towards (bio)molecular interconnects for NTs is outlined
Electron Devices Meeting, 2006. IEDM '06. International; 01/2007
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ABSTRACT: This paper deals with the design of broadband hybrid coupler in thin film microstrip (TFMS) technology for millimeter-wave applications in the G-band frequency range. The couplers to be designed are realized in BCB-based (benzo-cyclo-butene) technology. Classical 3-dB branch-line coupler is developed with 180-GHz central frequency. This coupler is used for the design of a wide-band matching network. Measurements performed in a wide frequency range up to 220-GHz attest from the design accuracy as well as the technological process quality
Microwave Conference, 2006. 36th European; 10/2006
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ABSTRACT: In this letter, the authors report on the high-frequency (HF) performance of self-assembled carbon nanotube field-effect transistors. HF device structures including a large number of single-wall carbon nanotubes have been designed and optimized in order to establish a new state of the art. The device exhibits a current gain (|H<sub>21</sub>| <sup>2</sup>) cutoff frequency (f<sub>t</sub>) of 8 GHz and a maximum stable gain value of 10 dB at 1 GHz, after de-embedding the access pads. Considering such results, nanotube-based circuits with gigahertz performance are now conceivable
IEEE Electron Device Letters 09/2006; · 2.85 Impact Factor
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ABSTRACT: AC performances of carbon nanotube field-effect transistors (CNT-FETs) are analyzed by means of scattering parameters measurements. The active ac properties of CNT-FETs are clearly demonstrated up to 80 MHz and indications of active behavior are obtained up to 1 GHz. From these measurements, a small signal equivalent circuit is proposed and validated up to 10 MHz. The extraction procedure and the determination of the intrinsic ac elements of CNT-FETs are pointed out
IEEE Transactions on Nanotechnology 08/2006; · 2.29 Impact Factor
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ABSTRACT: This paper deals with the design of broadband hybrid coupler in thin film microstrip (TFMS) technology for millimeter-wave applications in the G-band frequency range. The couplers to be designed are realized in BCB-based technology. The technological process as well as transmission lines characterization and optimization in term of attenuation are described. Classical 3-dB branch-line coupler is developed with 180-GHz central frequency. Then, based on this topology, a broadband coupler using series matching networks is developed. Such a topology allows to reach bandwidth over 50 %, with very flat coupling. Measurements performed in a wide frequency range up to 220 GHz attest from the design accuracy as well as the technological process quality
Microwave Symposium Digest, 2006. IEEE MTT-S International; 07/2006
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ABSTRACT: This letter is devoted to the design of passive coplanar devices in the G-frequency band from a classical electrical circuit approach. Indeed, as long as coplanar transmission lines are correctly dimensioned, analytical models based on quasi-TEM approximation can be used. Simulated and experimental results in the range 0.5 to 220GHz are compared. They are exemplified with a 200-GHz open-ended stub and a 165-GHz traditional third-order quarter-wavelength shunt-stub filter.
IEEE Microwave and Wireless Components Letters 12/2005; · 1.72 Impact Factor
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ABSTRACT: An eight stage distributed amplifier with 12.5 dB /spl plusmn/ 0.45 dB gain and 50 GHz bandwidth has been demonstrated in a commercially available 0.1 /spl mu/m metamorphic GaAs HEMT (MHEMT) technology. The amplifier has a minimum noise figure lower than 2.5 dB in the bandwidth. The group delay variation from 9 to 40 GHz is /spl plusmn/ 7.5 ps and circuit consumption is 0.4 W. Such amplifier has been packaged with a high responsivity photodiode into a fiber pig-tailed module. Eye diagrams measurements demonstrate the successful high-speed operation of the photoreceiver.
Gallium Arsenide and Other Semiconductor Application Symposium, 2005. EGAAS 2005. European; 11/2005
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ABSTRACT: An eight stage distributed amplifier with 12.5 dB plusmn 0.45 dB gain and 50 GHz bandwidth has been demonstrated in a commercially available 0.1 mum metamorphic GaAs HEMT (MHEMT) technology. The amplifier has a minimum noise figure lower than 2.5 dB in the bandwidth. The group delay variation, from 9 to 40 GHz is plusmn 7.5 ps and circuit consumption is 0.4 W. Such amplifier has been packaged with a high responsivity photodiode into a fiber pig-tailed module. Eye diagrams measurements demonstrate the successful high-speed operation of the photoreceiver
Microwave, Antenna, Propagation and EMC Technologies for Wireless Communications, 2005. MAPE 2005. IEEE International Symposium on; 09/2005
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ABSTRACT: An eight stage distributed amplifier with 12.5 dB ± 0.45 dB gain and 50 GHz bandwidth has been demonstrated in a commercially available 0.1 μm metamorphic GaAs HEMT (MHEMT) technology. The amplifier has a minimum noise figure lower than 2.5 dB in the bandwidth. The group delay variation from 9 to 40 GHz is ± 7.5 ps and circuit consumption is 0.4 W. Such amplifier has been packaged with a high responsivity photodiode into a fiber pig-tailed module. Eye diagrams measurements demonstrate the successful high-speed operation of the photoreceiver.
Microwave Symposium Digest, 2005 IEEE MTT-S International; 07/2005
