Search query: Carbon nanotube demonstration 1-GHz

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abstract: Along with ultralow energy delay products and symmetric complementary polarities, carbon nanotube field effect transistors (CNT FETs) are expected to be promising building blocks for energy efficient computing technology. However, the work frequencies of the existing CNT based complementary metal oxide semiconductor (CMOS) integrated circuits (ICs) are far below the requirement (850 MHz) in state of art wireless communication applications. In this work, we fabricated deep submicron CMOS FETs with considerably improved performance of n type CNT FETs and hence significantly promoted the work frequency of CNT CMOS ICs to 1.98 GHz. Based on these high speed and sensitive voltage controlled oscillators, we then presented a wireless sensor interface circuit with working frequency up to 1.5 GHz spectrum. As a preliminary demonstration, an energy efficient wireless temperature sensing interface system was realized combining a 150 mAh flexible Li ion battery and a flexible antenna (center frequency of 915 MHz) In general, the CMOS logic high speed CNT ICs showed outstanding energy efficiency and thus may potentially advance the application of CNT based electronics.
author_names: Lijun Liu

Li Ding

Donglai Zhong

Jie Han

Shuo Wang

Qinghai Meng

Chenguang Qiu

Xingye Zhang

Lian-Mao Peng

Zhiyong Zhang
title: Carbon Nanotube Complementary Gigahertz Integrated Circuits and Their Applications on Wireless Sensor Interface Systems.
venue: ACS nano
year: 2019

abstract: Due to their excellent electrical properties, metallic carbon nanotubes are promising materials for interconnect wires in future integrated circuits. Simulations have shown that the use of metallic carbon nanotube interconnects could yield more energy efficient and faster integrated circuits. The next step is to build an experimental prototype integrated circuit using carbon nanotube interconnects operating at high speed. Here, we report the fabrication of the first stand alone integrated circuit combining silicon transistors and individual carbon nanotube interconnect wires on the same chip operating above 1 GHz. In addition to setting a milestone by operating above 1 GHz, this prototype is also a tool to investigate carbon nanotubes on a silicon based platform at high frequencies, paving the way for future multi GHz nanoelectronics.
author_names: Gael F Close

Shinichi Yasuda

Bipul Chandra Paul

Shinobu Fujita

H -S Philip Wong
title: A 1 GHz integrated circuit with carbon nanotube interconnects and silicon transistors.
venue: Nano letters
year: 2008

abstract: In this study, to evaluate the electromagnetic shielding effect of UHPC/CNT composites by the content of CNTs, electromagnetic shielding effectiveness (SE) test was performed based on MIL STD 188 125 1 using specimens similar to actual size of exterior material. Then, experimental results were verified by applying Antenna theory of Schelkunoff. As the CNT contents increased, the SE at the same frequencies increased. However, contrary to the theory, the SE in the magnetic field was decreased with increase in frequency regardless of content of CNTs. The reason was due to the electromagnetic coupling effect and proved by using formula. Percolation threshold of CNT used in this experiment was 0.8~1 wt. of cement. In this case, the SE was maximized while maintaining the compressive strength and workability at levels similar to reference proportion. The SE when considering the electromagnetic coupling effect in the magnetic field was 18 dB at 10 kHz. And the SE in the plane wave (1 GHz) was about 22 dB. In conclusion, this composite could be used as a shielding material.
author_names: Myungjun Jung

Young-soon Lee

Sung-gul Hong
title: Study on Improvement in Electromagnetic Interference Shielding Effectiveness of Ultra High Performance Concrete (UHPC) Carbon Nanotube (CNT) Composites
venue: Journal of the Korea Concrete Institute
year: 2019

abstract: The energy efficiency demands of future abundant data applications, e.g. those which use inference based techniques to classify large amounts of data, exceed the capabilities of digital systems today. Field effect transistors (FETs) built using nanotechnologies, such as carbon nanotubes (CNTs) can improve energy efficiency significantly. However, carbon nanotube FETs (CNFETs) are subject to process variations inherent to CNTs: variations in CNT type (semiconductor or metallic) CNT density, or CNT diameter, to name a few. These CNT variations can degrade CNFET benefits at advanced technology nodes. One path to overcome CNT variations is to co optimize CNT processing and CNFET circuit design; however, the required CNT process advancements have not been achieved experimentally. We present a new design approach (TRIG, Technique for Reducing errors using Iterative Gray code) to overcome process variations in hardware accelerators targeting inference based applications that use serial matrix operations (serial: accumulated over at least 2 clock cycles) We demonstrate that TRIG can retain the major energy efficiency benefits (quantified using Energy Delay Product or EDP) of CNFETs despite CNT variations that exist in today's CNFET fabrication without requiring further CNT processing improvements to overcome CNT variations. As a case study, we analyze the effectiveness of TRIG for a binary neural network hardware accelerator that classifies images. Despite CNT variations that exist today, TRIG can maintain 99% (90% of projected EDP benefits of CNFET digital circuits for 90% (99% image classification accuracy target. We also demonstrate experimentally fabricated CNFET circuits to compute scalar product (a common matrix operation, also called dot product) with and without TRIG: TRIG reduces the mean difference between the expected result (no errors) and the experimentally computed result by 30 x in the presence of CNT variations, shown experimentally.
author_names: Gage Hills

Daniel Bankman

Bert Moons

Lita Yang

Jake Hillard

Alex Kahng

Rebecca Park

Marian Verhelst

Boris Murmann

Max M Shulaker

H -S Philip Wong

Subhasish Mitra
title: TRIG: Hardware Accelerator for Inference Based Applications and Experimental Demonstration Using Carbon Nanotube FETs
venue: 2018 55th ACM/ESDA/IEEE Design Automation Conference (DAC)
year: 2018

author_names: Gage Hills

Daniel Bankman

Bert Moons

Lita Yang

Jake Hillard

Alex Kahng

Rebecca Park

Marian Verhelst

Boris Murmann

Max M Shulaker

H -S Philip Wong

Subhasish Mitra
title: TRIG: hardware accelerator for inference based applications and experimental demonstration using carbon nanotube FETs
venue: DAC
year: 2018

abstract: Abstract Iron nanoparticles, iron nanochains and composite materials of iron nanoparticles and carbon nanotubes were prepared using a simple reduction method. The complex permittivity and complex permeability in the frequency range of 1 18 GHz were measured, upon which the reflection loss was calculated. Iron nanochains have achieved effective absorption of electromagnetic waves in the frequency range of 6 14 GHz when the thickness varies from 1.5 to 2.5 mm. Moreover, the reflection loss reaches 40 dB when the thickness is 2 mm, indicating that the absorption rate is almost 100% Composite materials of iron nanoparticles and carbon nanotubes have a better absorption performance in low frequency range (2.36 7.8 GHz) Iron nanochains are expected to become an excellent absorbent with strong absorption ability, wide band, small thickness and low cost. Composite materials of iron nanoparticles and carbon nanotubes are expected to be a light absorbent with good absorption of S and C bands (2 8 GHz, IEEE Std 521TM 2002) By analyzing the relationship between attenuation constant, impedance matching, and reflection loss, we verified that for optimal absorption, the attenuation constant and the impedance matching must be perfectly matched.
author_names: Hongzhe Tang

Yuejuan Chai

Dong Han
title: Controllable preparation of iron nanostructure/carbon nanotube composite materials and their microwave absorption properties
venue: Vacuum
year: 2019

abstract: Abstract Ceramic nanocomposites have been developed to provide a feasible and effective strategy in realizing extraordinary electromagnetic properties, such as negative permittivity. Here, copper calcium titanate CaCu3Ti4O12 (CCTO) nanocomposites incorporated with multiwall carbon nanotube (MWCNT) were prepared by spark plasma sintering (SPS) technology. It was found that MWCNT clusters were randomly embedded in CCTO matrix, which destroyed the microstructures of internal barrier layer capacitors in CCTO. The composites with low MWCNT content presented a hopping conduction behavior, while a metal like conduction behavior was observed in the ceramic with 18 wt% MWCNT content. Interestingly, weakly negative permittivity 103) was obtained in the ceramic consisting of interconnected MWCNT networks, as a great number of free electrons in the MWCNTs formed significantly collective oscillation state over 10 MHz 1 GHz range. Macroscopically, leakage current among MWCNT clusters or networks caused strong conduction loss at low frequencies. Equivalent circuit analysis manifested the correlation between low frequency plasmonic state and inductive character in the composite with negative permittivity. This work could extend the potential applications of ceramic nanocomposites to metamaterials.
author_names: Chuanbing Cheng

Yulin Wu

Yunpeng Qu

Rongwei Ma

Run-Hua Fan
title: Radio frequency negative permittivity of carbon nanotube/copper calcium titanate ceramic nanocomposites fabricated by spark plasma sintering
year: 2020

abstract: Abstract Up till now, metals, conductive polymers and carbon materials have been widely applied in electromagnetic interference (EMI) shielding. However, EMI shielding materials that are light weight, flexible, ultra thin, and mechanically robust are strongly needed for many civilian and military applications. In this study, a carbon nanotube (CNT)/polymer composite film of only 1 mm thick is prepared by continuous winding and deposition of a cylinder like CNT assembly impregnated with a polymer solution. The in situ impregnation leads to homogeneous mixing and strong tube tube interfacial bonding. Further optimization of the CNT content and alignment to high levels endows the thin composite film with a high tensile strength of 1250 MPa as well as a high EMI shielding effectiveness of 30 dB in the frequency range from 1 GHz to 18 GHz. Such a combination of mechanical and shielding properties surpasses all previous observations, and thus provides a new strategy for developing novel shielding materials for wide applications.
author_names: Guang Na Wu

Yun Chen

Hang Zhan

Hai-tao Chen

Jia Lin

J N Wang

Li Qiang Wan

Farong Huang
title: Ultrathin and flexible carbon nanotube/polymer composite films with excellent mechanical strength and electromagnetic interference shielding
year: 2020

abstract: Electromagnetic interference (EMI) shielding properties in the 1 18 GHz frequency range for multi walled carbon nanotube (MWNT) poly(vinylidene fluoride) (PVDF) composites are reported. A simple and gentle acid treatment of MWNT showed a percolation threshold (PT) of 0.15 wt% in the PVDF matrix as against 0.35 wt% for unfunctionalized MWNT. Acid treatment of MWNT significantly improves dispersion, interfacial adhesion with the matrix and the EMI shielding properties of PVDF composites. Further, the EMI shielding properties are correlated with the electrical properties. Using composite films of 0.3 mm thickness, the maximum shielding effectiveness (SET) values for 4 wt% unfunctionalized MWNT composites are found to be about 110, 45, 30, 26, and 58 dB for L (1 2 GHz) S (2 4 GHz) C (4 5.8 GHz) J (5.8 8 GHz) and X (8 12 GHz) bands, while the corresponding values for only 0.5 wt% acid functionalized MWNT composites are about 98, 45, 26, 19, and 47 dB, respectively. The electrical conductivity for both the cases is ~10( 3) S cm( 1) and the weight contents of CNTs are higher than the PT for the respective composites. The comparable EMI SE and electrical conductivity values for both the composites at different weight fractions of CNTs suggest that there is a critical electrical conductivity above which the composites attain improved EMI shielding properties. Further, the shielding mechanism was found to be dominated by absorption loss. Therefore, the composites may also serve as a radar absorbing material.
author_names: G Sudheer Kumar

D Vishnupriya

Anupam Joshi

Suwarna Datar

T Umasankar Patro
title: Electromagnetic interference shielding in 1 18 GHz frequency and electrical property correlations in poly(vinylidene fluoride) multi walled carbon nanotube composites.
venue: Physical chemistry chemical physics PCCP
year: 2015

author_names: Rasel Das
title: Nanohybrid Catalyst based on Carbon Nanotube: A Step By Step Guideline from Preparation to Demonstration
year: 2017