C
                  2
           column densities in H2/Ar/CH4 microwave plasmas

Goyette, A. N.; Matsuda, Yoshinobu; Anderson, L. W.; Lawler, J. E.

doi:10.1116/1.580992

Cited by 34 publications

(12 citation statements)

References 14 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…12 Previous studies 13,14 explored initial growth stages with dicarbon on the hydrogen-terminated ͑110͒ face without hydrogen abstraction by way of insertion of C 2 into C-H bonds on the surface. The presence of C 2 near the surface during growth and its likely contribution to the growth process have been confirmed experimentally through characteristic intense Swan-band radiation in both microwave plasma chemical vapor deposition 4,5 and hot-filament chemical vapor deposition. 6 In the present work, we consider deposition steps onto the clean diamond ͑110͒ surface without hydrogen participation.…”

Section: Introductionmentioning

confidence: 84%

“…Conventional diamond films as grown from H/CH 3 mixtures are characterized by crystallites in the micrometer size range. In several recent experiments [4][5][6] it was confirmed that the addition of argon to the plasma allows continuous control over the crystallite size. Most importantly, at argon concentrations in a narrow window around 95%, the resulting films are ultrananocrystalline with a typical crystallite size of just 3-10 nm.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Growth of (110) diamond using pure dicarbon

et al. 2001

View full text Add to dashboard Cite

We use a density-functional-based tight-binding method to study diamond growth steps by depositing dicarbon species onto a hydrogen-free diamond ͑110͒ surface. Subsequent C 2 molecules are deposited on an initially clean surface, in the vicinity of a growing adsorbate cluster, and finally near vacancies just before completion of a full new monolayer. The preferred growth stages arise from C 2n clusters in near ideal lattice positions forming zigzag chains running along the ͓1 10͔ direction parallel to the surface. The adsorption energies are consistently exothermic by 8-10 eV per C 2 , depending on the size of the cluster. The deposition barriers for these processes are in the range of 0.0-0.6 eV. For deposition sites above C 2n clusters the adsorption energies are smaller by 3 eV, but diffusion to more stable positions is feasible. We also perform simulations of the diffusion of C 2 molecules on the surface in the vicinity of existing adsorbate clusters using a constrained conjugate gradient method. We find migration barriers in excess of 3 eV on the clean surface, and 0.6-1.0 eV on top of graphenelike adsorbates. The barrier heights and pathways indicate that the growth from gaseous dicarbon proceeds either by direct adsorption onto clean sites or after migration on top of the existing C 2n chains.

show abstract

Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Growth of (110) diamond using pure dicarbon

et al. 2001

View full text Add to dashboard Cite

show abstract

“…33,38,50,70,88 C 2 radical density of 10 11 to 10 13 cm À3 was demonstrated in the MW and ICP systems employing a CH 4 /H 2 or CH 4 /H 2 /Ar mixture. [114][115][116] Teii et al conducted plasma diagnosis and material characterization on a TM-MW plasma (employing C 2 H 2 /N 2 /Ar or CH 4 /N 2 /Ar) as well as the as-grown deposits. 33 As shown in Fig.…”

Section: Carbon Sourcesmentioning

confidence: 99%

Plasma-enhanced chemical vapor deposition synthesis of vertically oriented graphene nanosheets

et al. 2013

View full text Add to dashboard Cite

Vertically oriented graphene (VG) nanosheets have attracted growing interest for a wide range of applications, from energy storage, catalysis and field emission to gas sensing, due to their unique orientation, exposed sharp edges, non-stacking morphology, and huge surface-to-volume ratio. Plasma-enhanced chemical vapor deposition (PECVD) has emerged as a key method for VG synthesis; however, controllable growth of VG with desirable characteristics for specific applications remains a challenge. This paper attempts to summarize the state-of-the-art research on PECVD growth of VG nanosheets to provide guidelines on the design of plasma sources and operation parameters, and to offer a perspective on outstanding challenges that need to be overcome to enable commercial applications of VG. The review starts with an overview of various types of existing PECVD processes for VG growth, and then moves on to research on the influences of feedstock gas, temperature, and pressure on VG growth, substrate pretreatment, the growth of VG patterns on planar substrates, and VG growth on cylindrical and carbon nanotube (CNT) substrates. The review ends with a discussion on challenges and future directions for PECVD growth of VG.

show abstract

“…Three years ago we reported observing the C 2 radical using absorption spectroscopy in a microwave plasma similar to that used to grow the nanometer scale polycrystalline films 1 . This work was performed in our own laboratory at the Univ.…”

Section: Subject Termsmentioning

confidence: 99%

Spectroscopic Studies of Diamond Growth

Anderson¹,

Lawler²

2000

Self Cite

View full text Add to dashboard Cite

SUPPLEMENTARY NOTESThe views, opinions and/or findings contained in this reoort are those of the a«*o^J and shouldnotl«construed as fficial Department of the Army position, policy or decision, unless so designated by other documentation. an official Departr High Sensitivity Absorption Spectroscopy (HSAS) was used to study the C 2 radical density in a hydrogen deficient Chemical Vapor Deposition (CVD) system for growing nanocrystalline diamond films. This work was performed in a collaboration between the University of Wisconsin group (supported by ARO) and Dr. Gruen's group at Argonne National Laboratory. The Q radical density is important because it is the likely growth specie in the hydrogen deficient growth environment. The Cj radical density was measured over large range of parameter space in the CVD reactor. Research on the power balance of the plasma in the CVD reactor was performed. A microwave interferometer is being used to measure electron densities. Concentrations of benzene, QjH«, far higher than predicted by models of diamond CVD systems have been detected. This discovery is an important step toward a more quantitative understanding of the carbon balance of diamond CVD systems.We have extended the HSAS technique for use in a Reflection-Absorption mode to study molecules physisorbed on metal surfaces. The heterogenous chemistry and surface physics of many CVD, semiconductor etching, and other plasma processesing systems are poorly understood. New in-situ surface diagnostics are needed to advance the understanding of the surface science of these important systems. The Ultraviolet Reflection-Absorption Spectroscopy (UVRAS) method has important advantages for insitu studies of processing environments. It has sensitivity to a small fraction of a monolayer. This high sensitivity is due to the fact that the oscillator strengths of electronic transitions in the UV are much larger than the oscillator strengths of vibrational transitions in the infrared which are probed using competing techniques. Optical techniques have a major advantage over many other surface diagnostics, such as electron spectroscopies, in that optical techniques do not require ultra high vacuum techniques and can be used under processing conditions.

show abstract

C 2 column densities in H2/Ar/CH4 microwave plasmas

Cited by 34 publications

References 14 publications

Growth of (110) diamond using pure dicarbon

Growth of (110) diamond using pure dicarbon

Plasma-enhanced chemical vapor deposition synthesis of vertically oriented graphene nanosheets

Spectroscopic Studies of Diamond Growth

Contact Info

Product

Resources

About