Origin of Conductive Nanocrystalline Diamond Nanoneedles for Optoelectronic Applications

Sankaran, Kamatchi Jothiramalingam; Yeh, Chien-Jui; Hsieh, Ping‐Yen; Pobedinskas, Paulius; Srinivasu, K.; Leou, Keh-Chyang; Tai, Nyan‐Hwa; Lin, I‐Nan; Haenen, Ken

doi:10.1021/acsami.9b05469

Cited by 22 publications

(23 citation statements)

References 72 publications

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“…Additionally, the power and pressure were set to be 900 W and 10 Torr, respectively. For the growth of the NOND film, the MPECVD reactor was operated at 1.4 kW power and 40 Torr using a mixture of 94% N 2 and 6% CH 4 as the reactant under a −300 V substrate bias. − …”

Section: Methodsmentioning

confidence: 99%

Nitrogen-Incorporated Ovoid-Shaped Nanodiamond Films for Dopamine Detection

Chang

Lee

Tai

2020

ACS Appl. Nano Mater.

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Nitrogen-incorporated ovoid-shaped nanodiamond (NOND) film exhibits excellent electrochemical sensing properties owing to its unique characteristics. In this study, to improve the sensitivity of NOND-based biosensors for dopamine (DA) detection, a detailed investigation concerning the growth mechanism of NOND films was conducted, it is found that the NOND films did not directly grow on a Si substrate during the growth process but preferentially originated from the formation of a thin Si3N4 interlayer attributed to the reactions of Si substrate and nitrogen atoms in the plasma in the very early stage of deposition. Subsequently, the diffusion of nitrogen from the inner Si3N4 to the Si3N4/plasma interface produces more active sites for the adsorption of the ionized carbon atoms. As the process proceeded further, the growth of ovoid-shaped diamonds accompanies the decrease of the Si3N4 interlayer thickness owing to the diffusion of nitrogen from Si3N4. Significant Si3N4 peaks are observed from both the Raman and X-ray diffraction analyses when the sample was subjected to NOND deposition for less than 20 min. These peaks then completely disappeared after deposition for 60 min, demonstrating the proposed mechanism. Furthermore, it is also observed that the deposition of the Si3N4 interlayer increased the hydrophilicity of the substrate, which is ascribed to the lower surface free energy of the NOND. To enhance the sensitivity of the NOND, the synthesis of NOND with patterned arrays (P-NOND) is proposed. The high specific surface area of the highly hydrophilic P-NOND obviously enhances the sensitivity of the P-NOND-based electrodes. Application of the P-NOND electrode for DA detection is successfully demonstrated in the mixed DA electrolyte, showing a better performance than that of the pristine NOND. This work reveals that the P-NOND electrode possesses superior sensitivity and selectivity, which is very favorable for DA sensing.

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Section: Methodsmentioning

confidence: 99%

Nitrogen-Incorporated Ovoid-Shaped Nanodiamond Films for Dopamine Detection

Chang

Lee

Tai

2020

ACS Appl. Nano Mater.

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“…This was probably due to an increase of the CN species that were more present as compared to the CH species [8]. Moreover, the NCD films were grown at a high growth temperature (>700 • C), which made it energetically favorable for the CN species to be more active, likely resulting in the formation of sp 2 -bonded carbon at the grain boundaries [10,26]. Hence CN, CH, and C 2 species were the main factors for the origin of the nanosized diamond grains and the induction of sp 2 -bonded carbon phases in the grain boundaries of 2% N 2 NCD films.…”

Section: Resultsmentioning

confidence: 99%

“…The C 2 swan system at 516.0 nm was also observed with low intensity [ 25 ]. Our previous studies stated that the presence of CH and C 2 species are responsible for the origin of nanosized diamond grains because the C 2 species re-nucleate diamond easily, whereas the CH species passivate the diamond nuclei and efficiently result in the formation of nanosized diamond grains [ 10 , 25 ]. Based on the recorded spectra, Figure 8 b shows a comparative graph of the species in the plasma during the growth.…”

Section: Resultsmentioning

confidence: 99%

“…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]. Still, the nanosized diamond grains are insulating in nature, which limits conduction to the grain boundaries, thereby limiting the FEE properties of N-doped NCD films.…”

Section: Introductionmentioning

confidence: 99%

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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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“…15 It is proposed that the electrical conduction in the grain boundaries is the main cause for improvement of the electron emission characteristics of the nitrogen-incorporated NCD films. 16 However, the insulating nature of nanosized diamond grains still confines the electrical conduction to the grain boundaries and thus limits the electron emission characteristics of NCD films. Instead, doping boron in diamond films can render diamond grains conductive because boron atoms substitute sp 3 -carbon atoms in the diamond lattice.…”

Section: ■ Introductionmentioning

confidence: 99%

Nitrogen-Incorporated Boron-Doped Nanocrystalline Diamond Nanowires for Microplasma Illumination

Sethy

Ficek

Sankaran

et al. 2021

ACS Appl. Mater. Interfaces

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The origin of nitrogen-incorporated boron-doped nanocrystalline diamond (NB-NCD) nanowires as a function of substrate temperature (T s ) in H 2 /CH 4 /B 2 H 6 /N 2 reactant gases is systematically addressed. Because of T s , there is a drastic modification in the dimensional structure and microstructure and hence in the several properties of the NB-NCD films. The NB-NCD films grown at low T s (400 °C) contain faceted diamond grains. The morphology changes to nanosized diamond grains for NB-NCD films grown at 550 °C (or 700 °C). Interestingly, the NB-NCD films grown at 850 °C possess one-dimensional nanowirelike morphological grains. These nanowire-like NB-NCD films possess the co-existence of the sp 3 -diamond phase and the sp 2graphitic phase, where diamond nanowires are surrounded by sp 2 -graphitic phases at grain boundaries. The optical emission spectroscopy studies stated that the CN, BH, and C 2 species in the plasma are the main factors for the origin of nanowire-like conducting diamond grains and the materialization of graphitic phases at the grain boundaries. Moreover, conductive atomic force microscopy studies reveal that the NB-NCD films grown at 850 °C show a large number of emission sites from the grains and the grain boundaries. While boron doping improved the electrical conductivity of the NCD grains, the nitrogen incorporation eased the generation of graphitic phases at the grain boundaries that afford conducting channels for the electrons, thus achieving a high electrical conductivity for the NB-NCD films grown at 850 °C. The microplasma devices using these nanowire-like NB-NCD films as cathodes display superior plasma illumination properties with a threshold field of 3300 V/μm and plasma current density of 1.04 mA/cm 2 with a supplied voltage of 520 V and a lifetime stability of 520 min. The outstanding plasma illumination characteristics of these conducting nanowire-like NB-NCD films make them appropriate as cathodes and pave the way for the utilization of these materials in various microplasma device applications.

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Origin of Conductive Nanocrystalline Diamond Nanoneedles for Optoelectronic Applications

Cited by 22 publications

References 72 publications

Nitrogen-Incorporated Ovoid-Shaped Nanodiamond Films for Dopamine Detection

Nitrogen-Incorporated Ovoid-Shaped Nanodiamond Films for Dopamine Detection

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

Nitrogen-Incorporated Boron-Doped Nanocrystalline Diamond Nanowires for Microplasma Illumination

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