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[IEEE 2019 IEEE International Conference on Design & Test of Integrated Micro & Nano-Systems (DTS) - Gammarth-Tunis, Tunisia (2019.4.28-2019.5.1)] 2019 IEEE International Conference on Design & Test of Integrated Micro & Nano-Systems (DTS) - Fast and Accurate Simulation of Ultrascaled Carbon Nanotube Field-Effect Transistor Using ANN Sub-Modeling Technique
摘要： In this paper, we have proposed a new modeling methodology based on the artificial neural networks (ANN) to simulate the ultra-scaled carbon nanotube field-effect transistor (CNTFET). The sub-modeling concept has been employed to efficiently simplify the overall modeling process. The developed sub-models have been compared with the mode space non- equilibrium Green’s function ( MS-NEGF) simulations in terms of the resulted drain current, where a good agreement has been recorded. In addition, simulation tests have shown that the proposed smart models are faster of about two order of magnitude over the standard MS-NEGF simulation. The obtained results indicate that the proposed ANN-based sub- modeling is an accurate and computationally efficient approach, which can be successfully used to simulate, analyze, and optimize the ultra-scaled CNTFETs and the futuristic CNT-based nanoscale integrated circuits.
关键词： computational intelligence,Artificial neural networks (ANN),non-equilibrium Green’s function (NEGF),numerical modeling,carbon nanotube (CNTFET)
更新于2025-09-12 10:27:22
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The State of HiPco Single-Walled Carbon Nanotubes in 2019
摘要： High-pressure carbon monoxide (HiPco)-synthesized single-walled carbon nanotubes (SWCNTs) have been a widely studied carbon nanomaterial for nearly two decades. It has been the de facto standard for SWCNT research, be it functionalization, separation and purification, or composites, as a result of the consistent, high-quality material that was made available at an affordable price to researchers worldwide. The recent shutdown of the HiPco reactor at Rice University has resulted in a scarcity of HiPco material available to the research community, and a new source of similar SWCNTs is desperately needed. Continued research and development on the design, materials used, and the overall process have led to a new HiPco material, referred to as NoPo HiPCO?, as an alternative to the erstwhile Rice HiPco SWCNTs. In this work, we have compared the two HiPco materials, and aim to provide more clarity for researchers globally on the state of HiPco SWCNTs for research and applications alike in 2019.
关键词： SWCNT,carbon nanotube,carbon,NoPo HiPCO?,HiPco
更新于2025-09-11 14:15:04
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Supramolecular structures of terbium( <scp>iii</scp> ) porphyrin double-decker complexes on a single-walled carbon nanotube surface
摘要： This work mainly reports the observation of novel supramolecular structures of TbIII-5,15-bisdodecylporphyrin (BDP, C12P) double-decker complexes on the surfaces of single-walled carbon nanotubes (SWNTs) performed by scanning tunneling microscopy under an ultra-high vacuum and low temperature, atomic force microscopy, scanning electron microscopy coupled with energy dispersive spectroscopy, and ultraviolet-visible spectroscopy. The molecules formed a well-ordered self-assembled helix-shaped array with regular periodicity on the tube surface. Additionally, some magnetic properties of the BDP-molecule as well as the resulting BDP-SWNT composites were investigated by superconducting quantum interference measurements. The molecule exhibits single-molecule magnetic (SMM) properties and the composite's magnetization increases almost linearly with decreasing temperature which is possibly due to the coupling between porphyrin molecules and SWNTs. Consequently, this may enable the development of more advanced spintronic devices based on porphyrin-nanocarbon composites.
关键词： Scanning tunneling microscopy,Magnetic properties,Supramolecular structures,Single-walled carbon nanotube,Atomic force microscopy,Terbium(III) porphyrin
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Saturable Absorption with CNT Coupled WGM and Fabrication of Er-Doped Microresonator for on-Chip Mode-Locked Laser
摘要： Mode-locked (ML) fiber lasers are becoming key components in industry, because they provide high performance while being relatively inexpensive. The generation of high-repetition rate pulses is gaining interest but it remains a challenge to achieve a GHz repetition rate with fiber lasers. On the other hand, whispering-gallery-mode (WGM) microresonators allow the strong confinement of light and miniaturizing an ML laser into a WGM microresonator will enable us to achieve a high pulse repetition rate, a small footprint and on-chip integrability. In this work, we explore the possibility of a passive ML laser with the system shown in Fig. 1(a). There are two key technologies involved; one is saturable absorption (SA) and the other is laser gain in a microresonator. First, we verified numerically that we could realize an ML laser with our proposed carbon nanotube (CNT) coupled erbium (Er) doped microresonator, and the result is shown in Fig. 1(b). We modelled our system with a nonlinear Schr?dinger equation, where we took gain and SA (also loss (Q), Kerr effect, and dispersion) into account [2]. The result shows that a self-starting ML is possible with microresonator parameters. Next, encouraged by the numerical result, we experimentally demonstrated SA in a microtoroid. We grew CNTs selectively on a silica microtoroid by chemical vapor deposition and investigated the SA behavior (Fig. 1(c)). By performing a pump-probe like experiment we successfully characterized the SA behavior in a microresonator system. This is the first demonstration of SA in a WGM microcavity system [1]. We then fabricated an Er-doped active microtoroid by using the sol-gel method. The sol-gel method is one way of forming silica from a metal alkoxide precursor. Although sol-gel has been widely used, it is still a challenge to fabricate high-quality defect-free film on a Si wafer that allows us to fabricate an ultrahigh-Q WGM microresonator. Figure 1(d)-(f) shows the fabricated films. We found optimum parameters and obtained a clean film as shown in Fig. 1(g). By using this film, we fabricated an Er-doped WGM microresonator, where the Q was 1.2×106 at 1480 nm (Fig. 1(h)). We obtained clear up-conversion luminescence when we pumped the cavity at 1480 nm, which constitutes the first step towards ML lasing in such a WGM microresonator. In summary, these results provide a promising approach for realizing an on-chip high repetition rate ML WGM microresonator.
关键词： saturable absorption,sol-gel method,carbon nanotube,whispering-gallery-mode microresonators,erbium-doped microresonator,Mode-locked fiber lasers
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - All-PM Fibre Laser with Switchable Pulsed Regimes Driven by Electrochemically Gated Carbon Nanotube Saturable Absorber
摘要： Pulse lasing driven by a real saturable absorber (SA) in a fibre laser cavity is conditional on modulation characteristics determined by the nonlinear material and implementation geometry of the SA. Generally, these parameters can be only preset during the SA fabrication. For instance, modulation depth of a single-wall carbon nanotube saturable absorber (SWCNT-SA) sandwiched between fibre connectors is governed by its thickness [1]. Here we demonstrate electronic control of pulse lasing regimes in an all-PM fibre laser by using an original electrochemically gated in-line SWCNT-SA. Earlier it was shown that electric gating of graphene can alter its nonlinear optical properties [2], but for SWCNT, to the best of our knowledge, there were no such studies.
关键词： switchable pulsed regimes,electrochemically gated carbon nanotube saturable absorber,all-PM fibre laser
更新于2025-09-11 14:15:04
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Layer-by-layer assembly of polyelectrolytes-wrapped multi-walled carbon nanotubes on long period fiber grating sensors
摘要： A new type of long period fiber grating (LPG) sensor coated with polyelectrolytes-wrapped multi-walled carbon nanotube (MWCNT) (PE-CNT) thin film is reported in this study. The novel morphologies of the MWCNT-based nanostructured thin film are observed by scanning electron microscopy characterization. The refractive index and pH sensing behaviors of LPGs with pure (PE)10 thin film and with (PE-CNT)10 thin film, respectively are compared. Results show that for LPG with (PE-CNT)10 thin film the transmission intensity at the resonance wavelength decreases noticeably with the increase of the surrounding refractive index. This is distinct from the sensing mechanism of LPG with (PE)10 thin film, which is based on the resonance wavelength shift. The LPG with a (PE-CNT)10 thin film provides enhanced pH sensitivity compared with that of a (PE)10 thin film. The LPG with (PE-CNT)10 thin film has a fast response rate and a good repeatability, thus demonstrating its strong potentiality for practical monitoring applications.
关键词： layer-by-layer assembly,sensor,thin film,Long period fiber grating,pH sensing,carbon nanotube
更新于2025-09-11 14:15:04
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Tiny nano-scale junction built on B/N doped single carbon nanotube
摘要： The characteristic sizes of carbon nanotube (CNT) based devices are constantly reduced. However, the continuous miniaturization is still facing many problems and requires innovative ideas and structures. By regular doping Boron and Nitrogen atoms in a semiconducting single-wall carbon nanotube (SWCNT), we have constructed an nano-scale junction with rectifying characteristics. The I-V curve of our junction resembles the I-V curve of an ideal diode with a p-n junction. This junction channel is about 0.6nm wide and 3.4nm long, and the footprint is 5.1nm long. Under 0.5V bias, the junction has a leakage current of -8.81×10-3 μA, a rectifying ratio Ion/Ioff of 0.716×103, and a current density of 10.52 mA/μm. Also, our study shows that how different dopant distribution influence I-V curve. Such a nano-scale regular doping method is effective and important, compared with the traditional random doping method.
关键词： B/N doped junction,I-V curve,density functional theory,non-equilibrium Green’s function,carbon nanotube,regular doping,electronic transport
更新于2025-09-11 14:15:04
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Stable iodide doping induced by photonic curing for carbon nanotube transparent conductive films
摘要： Doping has become crucial for achieving stable and high-performance conductive transparent carbon nanotube (CNT) ?lms. In this study, we systematically investigate the doping e?ects of a few materials including alkali metal iodides, nonmetal iodide, and metals. We demonstrate that photonic curing can enhance the doping e?ects, and correspondingly improve the conductivity of CNT ?lms, and that such iodides have better doping e?ects than metals. In particular, doping with a nonmetal compound (NH4I) shows the largest potential to improve the conductivity of CNT ?lms. Typically, doping with metal iodides reduces the sheet resistance (RS) of CNT ?lms with 70–80% optical transmittances at λ = 550 nm from 600–2400 to 250–440 Ω/square, whereas doping with NH4I reduces RS to 57 and 84 Ω/square at 74 and 84% optical transmittances, respectively. Interestingly, such a doped CNT ?lm exhibits only a slight increase in sheet resistance under an extreme environment of high temperature (85 °C) and high relative humidity (85%) for 350 h. The results suggest that photonic-curing-induced iodide doping is a promising approach to producing high-performance conductive transparent CNT ?lms.
关键词： transparent conductive ?lms,doping,iodide,carbon nanotube,photonic curing
更新于2025-09-10 09:29:36
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Printing Carbon Nanotube-embedded Silicone Elastomers via Direct Writing
摘要： Direct writing techniques for the printing of colloidal multiwalled carbon nanotubes (CNTs) embedded in polydimethylsiloxane (PDMS) were developed herein to fabricate complex structures including woodpiles, tetragonal scaffolds, and gradient mesh structures. The multiwalled CNTs served as a conductive filler and thickening agent for the printing ink. A suitable rheological behavior was obtained by mixing the CNTs with PDMS dissolved in an isopropyl alcohol solvent. A 7 wt.% CNT loading in the PDMS was optimum for printing gap-spanning features at a nozzle speed of 20 mm/s. The printed structures, including a woodpile and gradient mesh structure, were capable of detecting changes in external mechanical pressure. Printed CNT/PDMS strips exhibit electrical actuation with good mechanical performance (strain of 8.9%) at a low actuation voltage (60 V). The performance characterization and application display demonstrated the possibility of developing custom complex CNT/PDMS structures for a broad range of applications, including soft robots and flexible electronic devices.
关键词： polydimethylsiloxane,gap spanning features,multiwalled carbon nanotube (CNT),Direct writing,rheological behavior
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE Congress on Evolutionary Computation (CEC) - Rio de Janeiro (2018.7.8-2018.7.13)] 2018 IEEE Congress on Evolutionary Computation (CEC) - Confidence Measures for Carbon-Nanotube / Liquid Crystals Classifiers
摘要： This paper focuses on a performance analysis of single-walled-carbon-nanotube / liquid crystal classifiers produced by evolution in materio. A new confidence measure is proposed in this paper. It is different from statistical tools commonly used to evaluate the performance of classifiers in that it is based on physical quantities extracted from the composite and related to its state. Using this measure, it is confirmed that in an un-trained state, ie: before being subjected to an algorithm-controlled evolution, the carbon-nanotube-based composites classify data at random. The training, or evolution, process brings these composites into a state where the classification is no longer random. Instead, the classifiers generalise well to unseen data and the classification accuracy remains stable across tests. The confidence measure associated with the resulting classifier’s accuracy is relatively high at the classes’ boundaries, which is consistent with the problem formulation.
关键词： confidence measure,evolution in materio,classifiers,liquid crystal,single-walled-carbon-nanotube
更新于2025-09-10 09:29:36