Direct conversion of Teflon into nanodiamond films

Gupta, Siddharth; Narayan, J.

doi:10.1080/21663831.2020.1778111

Cited by 8 publications

(14 citation statements)

References 32 publications

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“…Our study involves regrowth of the undercooled BN melt (193 nm laser source) and ref involves localized laser heating (532 nm laser source) of the pre-existing c-BN nanoparticles. From our previous experiments and simulations on the C system, ,, we found that undercooling packs up the molten carbon making the simulation results obtained under HPHT conditions match with the results of the undercooled liquid-quenching experiments. Hence, the motivation toward employing the ExTEP pseudopotential, which works better under HPHT conditions and is reliable to simulate melting characteristics of c-BN and h-BN.…”

Section: Resultssupporting

confidence: 69%

Nanometer-Thick Hexagonal Boron Nitride Films for 2D Field-Effect Transistors

Gupta

Sachan

Narayan

2020

ACS Appl. Nano Mater.

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Hexagonal boron nitride (h-BN) is attracting significant attention as an ultimate dielectric and active layer in multifunctional 2D heterostructured devices because of its high bandgap and pliability to form layers as thin as an atomic monolayer. However, h-BN device integration is plagued with issues concerning the fabrication of stoichiometric films with a controlled layer thickness and wafer-scale integration. Here, we present a novel nonequilibrium approach to convert amorphous BN (a-BN), deposited at room temperature, into an epitaxial h-BN monolayer and multilayers by liquid-phase epitaxial regrowth. Nanosecond laser irradiation melts BN, forming an undercooled melt state above a threshold energy density (E d) of 0.3 J/cm2. Detailed Raman, X-ray photoelectron spectroscopy, low-energy electron nanodiffraction, high-angle annular dark-field imaging, and electron energy-loss spectroscopy analyses reveal the first-order phase transformation of a-BN into phase-pure epitaxial h-BN. This unique laser processing approach opens the cost-effective and spatially controlled synthesis approach to form h-BN thin films for nanophotonics and quantum processing. With these results, we propose that the nonequilibrium undercooling-assisted synthesis method can be employed to fabricate these atomically thin layers which are particularly attractive for use as atomic membranes or as dielectric layers/substrates in graphene-based devices, which can be scaled up for wafer-scale integration.

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Section: Resultssupporting

confidence: 69%

Nanometer-Thick Hexagonal Boron Nitride Films for 2D Field-Effect Transistors

Gupta

Sachan

Narayan

2020

ACS Appl. Nano Mater.

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“…[ 160 ] The phase transition of carbon through radical or transient intermediates also has been shown to have profound impacts on the final allotrope of the carbon product, [ 161 ] and further work has shown that fluorination of the substrate can result in increases in radical stability during phase transformations. [ 162,163 ] Thus, FJH of fluorinated organic carbon precursors was probed and resulted in controllable phase evolution. Fluorinated substrates included the use of Teflon and other perfluoroalkyl species.…”

Section: Extensions and Outlook Of Flash Joule Heatingmentioning

confidence: 99%

Large‐Scale Syntheses of 2D Materials: Flash Joule Heating and Other Methods

2022

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In the past 17 years, the larger‐scale production of graphene and graphene family materials has proven difficult and costly, thus slowing wider‐scale commercial applications. The quality of the graphene that is prepared on larger scales has often been poor, demonstrating a need for improved quality controls. Here, current industrial graphene synthetic and analytical methods, as well as recent academic advancements in larger‐scale or sustainable synthesis of graphene, defined here as weights more than 200 mg or films larger than 200 cm2, are compiled and reviewed. There is a specific emphasis on recent research in the use of flash Joule heating as a rapid, efficient, and scalable method to produce graphene and other 2D nanomaterials. Reactor design, synthetic strategies, safety considerations, feedstock selection, Raman spectroscopy, and future outlooks for flash Joule heating syntheses are presented. To conclude, the remaining challenges and opportunities in the larger‐scale synthesis of graphene and a perspective on the broader use of flash Joule heating for larger‐scale 2D materials synthesis are discussed.

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“…Laser irradiation is a novel method for synthesizing ND film with non-high temperature and non-high pressure. To date, many materials including graphite carbon, polytetrafluoroethylene (PTFE) was conducted to synthesize the ND films through the excimer pulsed laser annealing technology [ 27 , 28 , 81 , 82 ]. In 2014, Nian Q. et al explored a confined pulsed laser deposition (CPLD) technique with the order of nanosecond to produce the patterned ND films from a layer of graphite topped with a glass cover sheet at room temperature and normal pressure [ 27 ].…”

Section: Fabrication Methods and Nucleation Process Of Nanodiamond Filmmentioning

confidence: 99%

“…Despite of the graphite carbon, PTFE, commercially known as the Teflon, are used as the carbon source in the formation of ND films [ 28 , 81 ]. Gupta S. et al reported a direct argon fluoride excimer pulsed laser annealing (PLA) writing method for ND film with shorter duration (~100 ns) via melting PTFE in ambient condition in 2020, where the laser energy density is maintained at 1 J/cm 2 .…”

Section: Fabrication Methods and Nucleation Process Of Nanodiamond Filmmentioning

confidence: 99%

Recent Progress of Nanodiamond Film in Controllable Fabrication and Field Emission Properties

et al. 2023

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The interest in the field electron emission cathode nanomaterials is on the rise due to the wide applications, such as electron sources, miniature X-ray devices, display materials, etc. In particular, nanodiamond (ND) film is regarded as an ideal next-generation cathode emitter in the field emission devices, due to the low or negative electron affinity, small grain size, high mechanical hardness, low work function, and high reliability. Increasing efforts are conducted on the investigation of the emission structures, manufacturing cost, and field emission properties improvement of the ND films. This review aims to summarize the recent research, highlight the new findings, and provide a roadmap for future developments in the area of ND film electron field emitter. Specially, the optimizing methods of large-scale, high-quality, and cost-effective synthesis of ND films are discussed to achieve more stable surface structure and optimal physical properties. Additionally, the mainstream strategies applied to produce high field emission performance of ND films are analyzed in detail, including regulating the grain size/boundary, hybrid phase carbon content, and doping element/type of ND films; meanwhile, the problems existing in the related research and the outlook in this area are also discussed.

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Direct conversion of Teflon into nanodiamond films

Cited by 8 publications

References 32 publications

Nanometer-Thick Hexagonal Boron Nitride Films for 2D Field-Effect Transistors

Nanometer-Thick Hexagonal Boron Nitride Films for 2D Field-Effect Transistors

Large‐Scale Syntheses of 2D Materials: Flash Joule Heating and Other Methods

Recent Progress of Nanodiamond Film in Controllable Fabrication and Field Emission Properties

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