Thin films of nanocrystalline graphene/graphite: An overview of synthesis and applications

Simionescu, Octavian‐Gabriel; Popa, R.; Avram, Andrei; Dinescu, Gheorghe

doi:10.1002/ppap.201900246

Cited by 19 publications

(25 citation statements)

References 56 publications

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“…A proposed nomenclature for the diversified carbonic structures can be consulted in [23]. While respecting the aforementioned nomenclature as much as possible and considering its various characterizations [24][25][26], we define the material used in this work as bulk-NCG: a thick and hard carbonic film consisting of 3D randomly orientated, graphite nanocrystals with a dominant turbostratic packing [27] Thin films belonging to the broad class of NCG [27] have shown promise in applications such as: field emis-sion [28], electrochemical sensing [25,29,30], photodetection [31,32], nanoelectromechanical (NEM) switching [19], fabrication of microelectromechanical (MEM) resonators [20], protective coating [33] or gas separation [34]. The inhomogeneous conductive pathways formed by the sp 2 domains provide the material with a special functionality and a high conductivity response to small strains [10,18,35].…”

Section: Introductionmentioning

confidence: 99%

“…They obtained significant sensitivity enhancement by increasing the substrate temperature (from 525 ∘ C to 600 ∘ C) during the plasma process and, in accordance with the assumed tunneling based sensing mechanism, concluded that the key to that enhancement was the higher nucleation density, lower grain size and larger initial tunneling distance that resulted thereby. It is indeed known the beneficial effect of a higher substrate temperature on the film nucleation density [19,27,36].…”

Section: Introductionmentioning

confidence: 99%

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Nanocrystalline graphite thin layers for low-strain, high-sensitivity piezoresistive sensing

Simionescu

Pachiu

Ionescu

et al. 2020

Reviews on Advanced Materials Science

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Bulk nanocrystalline graphite has been investigated as a possible candidate for piezoresistive sensors. The thin films were grown using capacitively coupled plasma enhanced chemical vapor deposition and a technological workflow for the transfer of the active material onto flexible substrates was established in order to use the material as a piezoresitive element. Preliminary electrical measurements under mechanical strain were performed in order to test the piezoresistive response of the material and promising GF values of 50 − 250 at 1% strain were obtained.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Nanocrystalline graphite thin layers for low-strain, high-sensitivity piezoresistive sensing

Simionescu

Pachiu

Ionescu

et al. 2020

Reviews on Advanced Materials Science

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“…Graphene–polymer can be used to prepare thin films which find applications such as sensors, shielding, field-effect transistors, photodetectors, and gas separation membranes [ 214 ]. A thin film was prepared using GO with poly[2,5-bis(3-tetradecylthiophen-2-yl)thieno[3,2-b]thiophene] for an NO 2 sensor [ 215 ].…”

Section: Applicationsmentioning

confidence: 99%

Recent Studies on Dispersion of Graphene–Polymer Composites

2021

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Graphene is an excellent 2D material that has extraordinary properties such as high surface area, electron mobility, conductivity, and high light transmission. Polymer composites are used in many applications in place of polymers. In recent years, the development of stable graphene dispersions with high graphene concentrations has attracted great attention due to their applications in energy, bio-fields, and so forth. Thus, this review essentially discusses the preparation of stable graphene–polymer composites/dispersions. Discussion on existing methods of preparing graphene is included with their merits and demerits. Among existing methods, mechanical exfoliation is widely used for the preparation of stable graphene dispersion, the theoretical background of this method is discussed briefly. Solvents, surfactants, and polymers that are used for dispersing graphene and the factors to be considered while preparing stable graphene dispersions are discussed in detail. Further, the direct applications of stable graphene dispersions are discussed briefly. Finally, a summary and prospects for the development of stable graphene dispersions are proposed.

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“…The first step was the fabrication and physical/structural characterization of the NCG, as to provide useful data for the correct modelling of the material in the EM simulator used for the design of the antennas. The NCG deposition process was performed on the NANOFAB 1000 system (Oxford Instruments, UK), using the PECVD method [18]. The Si/SiO2 wafer was loaded in the preheated reactor (200°C) and heated up to 900°C at a ramp rate of 15°C/min in an Ar+H2 (5%) atmosphere.…”

Section: Ncg Thin Films Fabrication and Characterizationmentioning

confidence: 99%

Tunable 24-GHz Antenna Arrays Based on Nanocrystalline Graphite

Aldrigo¹,

Dragoman

Iordanescu

et al. 2021

IEEE Access

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In this work, we present a tunable 24-GHz antenna array based on a CMOS-compatible 110nm-thick nanocrystalline graphite film grown by plasma enhanced chemical vapor deposition. The film has a nominal bulk conductivity exceeding 16000 S/m (hence, greater than any graphene monolayer or industrially available graphene multilayer) but still able to show an outstanding modulation of its charge carrier density in the upper microwave spectrum. The manufactured layer was used to design, simulate, fabricate, and test a 24-GHz patch antenna array, with each radiating element having overall dimensions of just λ0/8×λ0/7. The fabricated array exhibits a measured maximum gain of about 3 dBi around 24 GHz (unbiased state), with a half-power beam width of only 14.5° (suitable in wireless links where a high directivity is envisaged). Spanning the dc bias voltage between -25 V and 25 V at 24 GHz, the gain can be tuned continuously between -1.5 dBi and 4 dBi, whereas the resonance frequency undergoes a maximum shift of 166 MHz. This voltage-dependent tuning of the gain represents a first step in developing carbonbased applications to control amplitude and phase simultaneously and independently. These results (never reported) demonstrate the big potential of nanocrystalline graphite for high-performance microwave components that are CMOS compatible (a highly desirable characteristic for high fabrication yield and largescale production), with unprecedented tunability for next-generation high-capacity communications.

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Thin films of nanocrystalline graphene/graphite: An overview of synthesis and applications

Cited by 19 publications

References 56 publications

Nanocrystalline graphite thin layers for low-strain, high-sensitivity piezoresistive sensing

Nanocrystalline graphite thin layers for low-strain, high-sensitivity piezoresistive sensing

Recent Studies on Dispersion of Graphene–Polymer Composites

Tunable 24-GHz Antenna Arrays Based on Nanocrystalline Graphite

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