Stacking of nanocrystalline graphene for nano-electro-mechanical (NEM) actuator applications

Kulothungan, Jothiramalingam; Schmidt, Marek E.; Muruganathan, Manoharan; Hammam, Ahmed; Mizuta, Hiroshi

doi:10.1007/s00542-018-4180-z

Cited by 5 publications

(6 citation statements)

References 22 publications

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“…In such covered devices (lid/graphene/water), no change on graphene resistivity is observed upon water injection into the channel. Therefore, differently from previous reports on electric‐field‐induced electromechanical effects in graphene resonators and switches, our results propose a novel type of electromechanical effect that is induced by water uncrumpling of the graphene membrane. Such action results in a reduction of the membrane wrinkling, which affects transport and optical properties of 2D materials .…”

Section: Introductioncontrasting

confidence: 99%

“…[1][2][3][4][5][6] Particularly, liquid/graphene interfaces have been exploited for bioapplications on cellular flow sensing, [7] liquid-sensing, [8] DNA sequencing, and transparent windows in liquid cells. Therefore, differently from previous reports on electric-field-induced electromechanical effects in graphene resonators and switches, [24][25][26][27][28][29] our results propose a novel type of electromechanical effect that is induced by water uncrumpling of the graphene membrane. [23] To suppress such uncrumpling effect, we also investigate the graphene membrane covered with thick hexagonal boron nitride (h-BN) flake, or poly(methyl methacrylate) (PMMA) film.…”

Section: Introductioncontrasting

confidence: 96%

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Graphene Electromechanical Water Sensor: The Wetristor

Meireles

Neto

Ferrari

et al. 2019

Adv Elect Materials

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between water and graphene is crucial for building up novel and smart biointerfaces. [18,19] Additionally, the study of reactivity and structure of water at the graphene interface has also generated intriguing questions and controversial results. [20,21] For instance, several experimental works demonstrate that the charge transfer process that happens between graphene and water molecules is highly dependent on the underlying substrate. [20,22] Thus, it would be highly desirable to elucidate the above discussion by probing the electrical response of a suspended graphene membrane in contact with water without the presence of any substrate. We also believe that a precise understanding of the electrochemical behavior of water/graphene interface would be fundamental for developing novel and superior electrical, mechanical, and optical devices.In the present work, we develop a microfluidic platform that integrates suspended graphene membrane windows (with electrical contacts) with buried fluid channels to probe the electrical response of a graphene membrane in contact with water. The platform design provides a direct probing of the electrical response of the air/graphene/liquid interface without the presence of any underlying substrate. [23] Our results show a significant change of graphene resistivity (of about 25%) due to the presence of water in the microchannel. The identification of the physical mechanisms behind such strong change in resistivity is not A water-induced electromechanical response in suspended graphene atop a microfluidic channel is reported. The graphene membrane resistivity rapidly decreases to ≈25% upon water injection into the channel, defining a sensitive "channel wetting" device-a wetristor. The physical mechanism of the wetristor operation is investigated using two graphene membrane geometries, either uncovered or covered by an inert and rigid lid (hexagonal boron nitride multilayer or poly(methyl methacrylate) film). The wetristor effect, namely the water-induced resistivity collapse, occurs in uncovered devices only. Atomic force microscopy and Raman spectroscopy indicate substantial morphology changes of graphene membranes in such devices, while covered membranes suffer no changes, upon channel water filling. The results suggest an electromechanical nature for the wetristor effect, where the resistivity reduction is caused by unwrinkling of the graphene membrane through channel filling, with an eventual direct doping caused by water being of much smaller magnitude, if any. The wetristor device should find useful sensing applications in general micro-and nanofluidics.

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Section: Introductioncontrasting

confidence: 99%

Section: Introductioncontrasting

confidence: 96%

Graphene Electromechanical Water Sensor: The Wetristor

Meireles

Neto

Ferrari

et al. 2019

Adv Elect Materials

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“…The steep switching slope (SS) for the first switching cycle from the Is-Va curves were determined as <10 mV/dec for the pull-in (SS pull-in) and < 10 mV/dec for pull-out (SS pull-out). The respective on/off ratio of the switching current is ∼ 10 9 orders of magnitude, which is higher than those of previously reported studies on graphenebased NEM contact switches [34,37,38,40]. (See supplementary section-VI for more information on electrical failure analysis of G-G NEM contact switch).…”

Section: Electrical Characterization Of G-g Nem Contact Switchesmentioning

confidence: 63%

“…In addition, various carbon-based nano materials are also employed as the contact material to improve the contact lifetime of the NEM contact switch. For instance, the suspended CNT beam with diamond-like carbon as contact [31], vertically aligned CNTs with CNT as contact layer [32], multilayer graphene with multilayer graphene as contact [33], nano crystalline graphene (NCG) with NCG as contact material [34] and graphite-to-graphite contact [35], have been studied earlier for electromechanical contact devices, inertial switches [32] and charge transfer based gas sensor applications [36]. However, this new generation materials based NEM contact switches were also failed to offer a high contact lifetime due to contact degradation.…”

Section: Introductionmentioning

confidence: 99%

A Large Scale Fabrication of Graphene Based Nano-electromechanical Contact Switches With Ultra-low Pull-in Voltage

Kulothungan¹

2022

Preprint

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Nano-electromechanical (NEM) contact switches have been extensively studied to suppress the limitations of conventional complementary metal-oxide-semiconductor (CMOS) transistors. The attributes of NEM contact switches includes reduced power consumption, reduced off-state leakage current, increased on-state current and sub-thermal switching. However, unacceptably high pull-in voltage and low contact lifetime posed a significant challenge for the use of NEM contact switches in energy efficient CMOS applications. Here, we demonstrate a graphene-based electro-statically actuated NEM contact switches with ultra-low pull-in voltage and significant improvement in the contact lifetime. This was achieved by using the graphene on gold electrode as a contact material. The graphene NEM contact switches with graphene as a contact material exhibits an ultra-low pull-in voltage of < 0.5 V and high contact lifetime of more than 1.5×10 6 cycles. The switches also showed an excellent switching performance with high on/off ratio of ∼ 10 8 , an extremely low off-state current of ∼100 fA, and small hysteresis window of < 0.1 V.

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“…[28][29][30] In addition, various carbon-based nano materials are also employed as the contact material to improve the contact lifetime of the NEM contact switch. For instance, the suspended CNT beam with diamond-like carbon as contact, [31] vertically aligned CNTs with CNT as contact layer, [32] multilayer graphene with multilayer graphene as contact, [33] nano crystalline graphene (NCG) with NCG as contact material [34] and graphite-to-graphite contact, [35] have been studied earlier for electromechanical contact devices, inertial switches [32] and charge transfer based gas sensor applications. [36] However, this new generation materials based NEM contact switches were also failed to offer a high contact lifetime due to contact degradation.…”

Section: Introductionmentioning

confidence: 99%

Large Scale Fabrication of Graphene Based Nano‐Electromechanical (NEM) Contact Switches with Sub‐0.5 Volt Actuation

Kulothungan¹,

Kandhasamy²

2022

Advanced Physics Research

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Nano-electromechanical (NEM) contact switches are extensively studied to suppress the limitations of conventional complementary metal-oxidesemiconductor (CMOS) transistors. The attributes of NEM contact switches includes reduced power consumption, reduced off-state leakage current, and increased on-state current and sub-thermal switching. However, unacceptably high pull-in voltage and low contact lifetime posed a significant challenge for the use of NEM contact switches in energy efficient CMOS applications. Here, graphene-based electro-statically actuated NEM contact switches with ultra-low pull-in voltage and significant improvement in the contact lifetime are demonstrated. This is achieved by using the graphene on gold electrode as a contact material. The graphene NEM contact switches with graphene as a contact material exhibit an ultra-low pull-in voltage of < 0.5 V and high contact lifetime of more than 1.5× 10 6 cycles. The switches also show an excellent switching performance with high on/off ratio of ≈10 8 , an extremely low off-state current of ≈100 fA, and small hysteresis window of < 0.1 V.

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Stacking of nanocrystalline graphene for nano-electro-mechanical (NEM) actuator applications

Cited by 5 publications

References 22 publications

Graphene Electromechanical Water Sensor: The Wetristor

Graphene Electromechanical Water Sensor: The Wetristor

A Large Scale Fabrication of Graphene Based Nano-electromechanical Contact Switches With Ultra-low Pull-in Voltage

Large Scale Fabrication of Graphene Based Nano‐Electromechanical (NEM) Contact Switches with Sub‐0.5 Volt Actuation

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