Structural evolution of laser-irradiated ultrananocrystalline diamond/amorphous carbon composite films prepared by coaxial arc plasma

Zkria, Abdelrahman; Abubakr, Eslam; Egiza, Mohamed; Haque, Ariful; Narayan, J.; Yoshitake, Tsuyoshi

doi:10.35848/1882-0786/abb871

Cited by 18 publications

(10 citation statements)

References 27 publications

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“…Similar results have been reported in laser-irradiated nanocrystalline diamond and low-energy ion-irradiated diamond. [41,42] The amorphous carbon of the intermediate layer formed at the interface should partially originate from the damage of FIB during TEM sample fabrication processes. It has been reported that the structural and compositional properties of interfaces fabricated by SAB were largely modified during FIB processes operated at room temperature, especially for wide bandgap materials.…”

Section: Resultsmentioning

confidence: 99%

Fabrication of GaN/Diamond Heterointerface and Interfacial Chemical Bonding State for Highly Efficient Device Design

et al. 2021

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The direct integration of gallium nitride (GaN) and diamond holds much promise for high‐power devices. However, it is a big challenge to grow GaN on diamond due to the large lattice and thermal‐expansion coefficient mismatch between GaN and diamond. In this work, the fabrication of a GaN/diamond heterointerface is successfully achieved by a surface activated bonding (SAB) method at room temperature. A small compressive stress exists in the GaN/diamond heterointerface, which is significantly smaller than that of the GaN‐on‐diamond structure with a transition layer formed by crystal growth. A 5.3 nm‐thick intermediate layer composed of amorphous carbon and diamond is formed at the as‐bonded heterointerface. Ga and N atoms are distributed in the intermediate layer by diffusion during the bonding process. Both the thickness and the sp2‐bonded carbon ratio of the intermediate layer decrease as the annealing temperature increases, which indicates that the amorphous carbon is directly converted into diamond after annealing. The diamond of the intermediate layer acts as a seed crystal. After annealing at 1000 °C, the thickness of the intermediate layer is decreased to approximately 1.5 nm, where lattice fringes of the diamond (220) plane are observed.

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Section: Resultsmentioning

confidence: 99%

Fabrication of GaN/Diamond Heterointerface and Interfacial Chemical Bonding State for Highly Efficient Device Design

et al. 2021

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“…The pulse duration of the laser pulse plays a critical role in determining the crystallinity . The regrowth velocity is low for broader pulses, which provides the interfacial atoms of the melt front sufficient time to ascend the lattice positions and leads to the crystallization . This framework provides a guideline to standardize the PLA parameters for controlling the undercooling and thereby the regrowth velocity, which ultimately enables to fabricate structures with desirable properties.…”

Section: Resultsmentioning

confidence: 99%

“…39 The regrowth velocity is low for broader pulses, which provides the interfacial atoms of the melt front sufficient time to ascend the lattice positions and leads to the crystallization. 40 This framework provides a guideline to standardize the PLA parameters for controlling the undercooling and thereby the regrowth velocity, which ultimately enables to fabricate structures with desirable properties. As this is a liquid-phase-mediated ultrafast crystal growth process, dopants do not segregate or form clusters, rather the solute trapping phenomenon is used to effectively dope the material at the high concentration level.…”

Section: Electrical Transport Measurementsmentioning

confidence: 99%

Tunable n-Type Conductivity and Transport Properties of Cubic Boron Nitride via Carbon Doping

Haque

Narayan

2021

ACS Appl. Electron. Mater.

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The recent discovery of direct conversion of hexagonal boron nitride (h-BN) into quenched BN (Q-BN) and single-crystal cubic BN (c-BN) by pulsed laser annealing (PLA) have been implemented to fabricate carbon-doped c-BN with dopant concentration ranging from 2 × 10 19 to 7 × 10 21 cm −3 . Micro Raman analysis shows a total conversion of h-BN into phase-pure c-BN, whereas the X-ray diffraction (XRD) confirms the presence of the cubic structure with (111) epitaxy on c-sapphire. Hall measurements demonstrate the n-type electrical property, and the temperature-dependent resistivity measurements confirm the semiconductor-like profile of the doped c-BN. Consistent changes in resistivity, Hall mobility, and other electrical properties were investigated with the variance in dopant concentration level. We have observed a shift in the conduction mechanism with temperature from the resistivity vs temperature analyses. At the hightemperature regime (130−330 K), the activation energy lies in between 0.012 and 0.074 eV, whereas at the low-temperature regime (20−130 K), the activation energy was obtained to be in between 0.0024 and 0.0083 eV. The lower values of activation energies, showing a complete ionization of the impurity atoms even at room temperature, are surmised to result from dopant-profile broadening. The enhanced electrical activation and superior quality c-BN films open exciting avenues for next-generation device applications.

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“…Compared to the undoped film (only in H 2 atmosphere), all nitrogen-doped NCD films (3, 5, 6, 8 at.%) exhibited three additional components, as shown in Figure 5 a. For more analysis of peak components, NEXAFS spectra of minimum (3 at.%) and maximum (8 at.%) values of nitrogen contents were deconvoluted into component peaks, with the similar processes described in our previous work [ 29 ], as presented in Figure 5 b. In Figure 5 b, the NEXAFS spectra with peak positions at 286.7 and 289.2 eV originated from π *C=N and σ *C−N [ 30 ].…”

Section: Resultsmentioning

confidence: 86%

Correlated Electrical Conductivities to Chemical Configurations of Nitrogenated Nanocrystalline Diamond Films

et al. 2022

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Diamond is one of the fascinating films appropriate for optoelectronic applications due to its wide bandgap (5.45 eV), high thermal conductivity (3320 W m−1·K−1), and strong chemical stability. In this report, we synthesized a type of diamond film called nanocrystalline diamond (NCD) by employing a physical vapor deposition method. The synthesis process was performed in different ratios of nitrogen and hydrogen mixed gas atmospheres to form nitrogen-doped (n-type) NCD films. A high-resolution scanning electron microscope confirmed the nature of the deposited films to contain diamond nanograins embedded into the amorphous carbon matrix. Sensitive spectroscopic investigations, including X-ray photoemission (XPS) and near-edge X-ray absorption fine structure (NEXAFS), were performed using a synchrotron beam. XPS spectra indicated that the nitrogen content in the film increased with the inflow ratio of nitrogen and hydrogen gas (IN/H). NEXAFS spectra revealed that the σ*C–C peak weakened, accompanied by a π*C=N peak strengthened with nitrogen doping. This structural modification after nitrogen doping was found to generate unpaired electrons with the formation of C–N and C=N bonding in grain boundaries (GBs). The measured electrical conductivity increased with nitrogen content, which confirms the suggestion of structural investigations that nitrogen-doping generated free electrons at the GBs of the NCD films.

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Structural evolution of laser-irradiated ultrananocrystalline diamond/amorphous carbon composite films prepared by coaxial arc plasma

Cited by 18 publications

References 27 publications

Fabrication of GaN/Diamond Heterointerface and Interfacial Chemical Bonding State for Highly Efficient Device Design

Fabrication of GaN/Diamond Heterointerface and Interfacial Chemical Bonding State for Highly Efficient Device Design

Tunable n-Type Conductivity and Transport Properties of Cubic Boron Nitride via Carbon Doping

Correlated Electrical Conductivities to Chemical Configurations of Nitrogenated Nanocrystalline Diamond Films

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