Liquid phase regrowth of 〈110〉 nanodiamond film by UV laser annealing of PTFE to generate dense CVD microdiamond film

Joshi, Pratik; Gupta, Siddharth; Riley, Parand R.; Narayan, Roger J.; Narayan, J.

doi:10.1016/j.diamond.2021.108481

Cited by 10 publications

(13 citation statements)

References 64 publications

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“…When the latent heat produced was insufficient to melt the underlayer, the process ended. BN melt subsequently grew back into h-BN, c-BN, or Q-BN phases based on the extent of undercooling achieved [ 38 , 39 ]. To better understand the mechanism underlying the evolution of h-BN film nanostructures during laser annealing, we simulated laser interactions using extremely accurate heat flow equations.…”

Section: Resultsmentioning

confidence: 99%

Fabricating Graphene Oxide/h-BN Metal Insulator Semiconductor Diodes by Nanosecond Laser Irradiation

et al. 2022

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To employ graphene’s rapid conduction in 2D devices, a heterostructure with a broad bandgap dielectric that is free of traps is required. Within this paradigm, h-BN is a good candidate because of its graphene-like structure and ultrawide bandgap. We show how to make such a heterostructure by irradiating alternating layers of a-C and a-BN film with a nanosecond excimer laser, melting and zone-refining constituent layers in the process. With Raman spectroscopy and ToF-SIMS analyses, we demonstrate this localized zone-refining into phase-pure h-BN and rGO films with distinct Raman vibrational modes and SIMS profile flattening after laser irradiation. Furthermore, in comparing laser-irradiated rGO-Si MS and rGO/h-BN/Si MIS diodes, the MIS diodes exhibit an increased turn-on voltage (4.4 V) and low leakage current. The MIS diode I-V characteristics reveal direct tunneling conduction under low bias and Fowler-Nordheim tunneling in the high-voltage regime, turning the MIS diode ON with improved rectification and current flow. This study sheds light on the nonequilibrium approaches to engineering h-BN and graphene heterostructures for ultrathin field effect transistor device development.

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Section: Resultsmentioning

confidence: 99%

Fabricating Graphene Oxide/h-BN Metal Insulator Semiconductor Diodes by Nanosecond Laser Irradiation

et al. 2022

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“…Therefore, the excitation of phonons leads to the generation of a significant amount of heat within 20 ns. We have previously shown that the 20 ns pulse duration is sufficient for PTFE to be heated and melted [48]. When PTFE is heated to 470 • C in air, volatilization of C 2 F 4 , C 3 F 6 , HF, CO 2 , and CO occurs [89].…”

Section: Mechanism Of Conversion Of Ptfe Into Rgo By the Pla Methodsmentioning

confidence: 99%

“…Fourier-transform infrared spectroscopy (FTIR, Bruker ALPHA) was carried out in the absorbance mode, with a resolution of 4 cm −1 and in the range of 500-4000 cm −1 ; background subtraction was performed. 100), ( 110), ( 200), (107), and (210) peaks of PTFE, respectively [47][48][49]. The crystallinity of PTFE can be calculated from its XRD pattern by using the Hermans-Weidinger method [50], using the following equation [51]:…”

Section: Characterizationmentioning

confidence: 99%

One-Step Formation of Reduced Graphene Oxide from Insulating Polymers Induced by Laser Writing Method

et al. 2021

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Finding a low-cost and effective method at low temperatures for producing reduced graphene oxide (rGO) has been the focus of many efforts in the research community for almost two decades. Overall, rGO is a promising candidate for use in supercapacitors, batteries, biosensors, photovoltaic devices, corrosion inhibitors, and optical devices. Herein, we report the formation of rGO from two electrically insulating polymers, polytetrafluoroethylene (PTFE) and meta-polybenzimidazole fiber (m-PBI), using an excimer pulsed laser annealing (PLA) method. The results from X-ray diffraction, scanning electron microscopy, electron backscattered diffraction, Raman spectroscopy, and Fourier-transform infrared spectroscopy confirm the successful generation of rGO with the formation of a multilayered structure. We investigated the mechanisms for the transformation of PTFE and PBI into rGO. The PTFE transition occurs by both a photochemical mechanism and a photothermal mechanism. The transition of PBI is dominated by a photo-oxidation mechanism and stepwise thermal degradation. After degradation and degassing procedures, both the polymers leave behind free molten carbon with some oxygen and hydrogen content. The free molten carbon undergoes an undercooling process with a regrowth velocity (<4 m·s−1) that is necessary for the formation of rGO structures. This approach has the potential for use in creating future selective polymer-written electronics.

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“…Reprinted from Ref. [47], Copyright (2013), with permission from RSC Publications can be misidentified as SARS-CoV-2 viral particles [59][60][61]. Autolysis of structures in autopsy samples can present challenges during EM-based identification of virus-associated cellular changes [60].…”

Section: Electron Microscopymentioning

confidence: 99%

“…Resonant wavelengths are generated by manipulating the electromagnetic fields associated with the light emitted from photonic crystals. As such, an electromagnetic standing wave showing intensities relative to the intensities of an illuminating light source is generated [ 45 , 46 , 47 ]. Furthermore, it has been demonstrated that gold nanoparticles (AuNP) with localized surface plasmon resonance (LSPR) overlap with the resonant electromagnetic field of a photonic crystal, resulting in a significant amplification of the absorption efficiency [ 48 ].…”

Section: Microscopic Techniquesmentioning

confidence: 99%

Novel photonic methods for diagnosis of SARS‐CoV‐2 infection

Joshi

Shukla

Narayan

2022

Transl Biophotonics

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The COVID-19 pandemic that began in March 2020 continues in many countries. The ongoing pandemic makes early diagnosis a crucial part of efforts to prevent the spread of SARS-CoV-2 infections. As such, the development of a rapid, reliable, and low-cost technique with increased sensitivity for detection of SARS-CoV-2 is an important priority of the scientific community. At present, nucleic acid-based techniques are primarily used as the reference approach for the detection of SARS-CoV-2 infection. However, in several cases, false positive results have been observed with these techniques. Due to the drawbacks associated with existing techniques, the development of new techniques for the diagnosis of COVID-19 is an important research activity. We provide an overview of novel diagnostic methods for SARS-CoV-2 diagnosis that integrate photonic technology with artificial intelligence. Recent developments in emerging diagnostic techniques based on the principles of advanced molecular spectroscopy and microscopy are considered.

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Liquid phase regrowth of 〈110〉 nanodiamond film by UV laser annealing of PTFE to generate dense CVD microdiamond film

Cited by 10 publications

References 64 publications

Fabricating Graphene Oxide/h-BN Metal Insulator Semiconductor Diodes by Nanosecond Laser Irradiation

Fabricating Graphene Oxide/h-BN Metal Insulator Semiconductor Diodes by Nanosecond Laser Irradiation

One-Step Formation of Reduced Graphene Oxide from Insulating Polymers Induced by Laser Writing Method

Novel photonic methods for diagnosis of SARS‐CoV‐2 infection

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