Microwave cavity perturbation of nitrogen doped nano-crystalline diamond films

Cuenca, Jerome A.; Sankaran, Kamatchi Jothiramalingam; Pobedinskas, Paulius; Panda, Kalpataru; Lin, I‐Nan; Porch, Adrian; Haenen, Ken; Williams, Oliver A.

doi:10.1016/j.carbon.2018.12.025

Cited by 25 publications

(21 citation statements)

References 38 publications

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“…Our hypothesis is that when the Gaussian laser beam, during the raster scan process, irradiates with its tails (i.e., at a fluence between the modification threshold and the ablation one), a grain boundary exposed to a compressed air or a N 2 flow, incorporation of nitrogen is strongly enhanced by local heating. This leads to bond distortions [ 32 ], induces a significant mechanical stress in the surrounding lattice, and increases the number of vacancy defects [ 33 ]. As a consequence, the ablation threshold decreases in correspondence of a grain boundary, as well as in its neighborhood, so that the subsequent full-spot irradiation (i.e., at the peak fluence) results in a much higher ablation rate.…”

Section: Resultsmentioning

confidence: 99%

Femtosecond-Laser Nanostructuring of Black Diamond Films under Different Gas Environments

et al. 2020

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Irradiation of diamond with femtosecond (fs) laser pulses in ultra-high vacuum (UHV) conditions results in the formation of surface periodic nanostructures able to strongly interact with visible and infrared light. As a result, native transparent diamond turns into a completely different material, namely “black” diamond, with outstanding absorptance properties in the solar radiation wavelength range, which can be efficiently exploited in innovative solar energy converters. Of course, even if extremely effective, the use of UHV strongly complicates the fabrication process. In this work, in order to pave the way to an easier and more cost-effective manufacturing workflow of black diamond, we demonstrate that it is possible to ensure the same optical properties as those of UHV-fabricated films by performing an fs-laser nanostructuring at ambient conditions (i.e., room temperature and atmospheric pressure) under a constant He flow, as inferred from the combined use of scanning electron microscopy, Raman spectroscopy, and spectrophotometry analysis. Conversely, if the laser treatment is performed under a compressed air flow, or a N2 flow, the optical properties of black diamond films are not comparable to those of their UHV-fabricated counterparts.

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Section: Resultsmentioning

confidence: 99%

Femtosecond-Laser Nanostructuring of Black Diamond Films under Different Gas Environments

et al. 2020

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“…Although the effect of the methane concentration on the process of CVD synthesis was reported [14][15][16][17][18], device-grade SCDs (FWHM < 60 arcsec, RMS < 1 nm) produced in a pure methane-hydrogen microwave plasma were not addressed in the previous methane optimization studies.…”

Section: Introductionmentioning

confidence: 99%

Evolution of High-Quality Homoepitaxial CVD Diamond Films Induced by Methane Concentration

et al. 2021

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“…Nitrogen addition in CH 4 /H 2 plasma effectively reduces the size of the diamond grains from micron to nanosized, yielding nanocrystalline diamond (NCD) films. It also facilitates the formation of nanographitic phases in the grain boundaries, for which an improvement in the electrical conductivity and subsequent FEE properties have been demonstrated [5][6][7][8]. The grain boundary conduction mechanism has been proposed for the enhancement of FEE properties of these N-doped NCD films [9,10].…”

Section: Introductionmentioning

confidence: 99%

Improved Field Electron Emission Properties of Phosphorus and Nitrogen Co-Doped Nanocrystalline Diamond Films

et al. 2020

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Nanocrystalline diamond (NCD) field emitters have attracted significant interest for vacuum microelectronics applications. This work presents an approach to enhance the field electron emission (FEE) properties of NCD films by co-doping phosphorus (P) and nitrogen (N) using microwave plasma-enhanced chemical vapor deposition. While the methane (CH4) and P concentrations are kept constant, the N2 concentration is varied from 0.2% to 2% and supplemented by H2. The composition of the gas mixture is tracked in situ by optical emission spectroscopy. Scanning electron microscopy, atomic force microscopy (AFM), transmission electron microscopy, and Raman spectroscopy are used to provide evidence of the changes in crystal morphology, surface roughness, microstructure, and crystalline quality of the different NCD samples. The FEE results display that the 2% N2 concentration sample had the best FEE properties, viz. the lowest turn-on field value of 14.3 V/µm and the highest current value of 2.7 µA at an applied field of 73.0 V/µm. Conductive AFM studies reveal that the 2% N2 concentration NCD sample showed more emission sites, both from the diamond grains and the grain boundaries surrounding them. While phosphorus doping increased the electrical conductivity of the diamond grains, the incorporation of N2 during growth facilitated the formation of nano-graphitic grain boundary phases that provide conducting pathways for the electrons, thereby improving the FEE properties for the 2% N2 concentrated NCD films.

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Microwave cavity perturbation of nitrogen doped nano-crystalline diamond films

Cited by 25 publications

References 38 publications

Femtosecond-Laser Nanostructuring of Black Diamond Films under Different Gas Environments

Femtosecond-Laser Nanostructuring of Black Diamond Films under Different Gas Environments

Evolution of High-Quality Homoepitaxial CVD Diamond Films Induced by Methane Concentration

Improved Field Electron Emission Properties of Phosphorus and Nitrogen Co-Doped Nanocrystalline Diamond Films

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