An atomic carbon source for high temperature molecular beam epitaxy of graphene

Albar, J.D.; Summerfield, Alex; Cheng, T.S.; Davies, Andrew J.; Smith, Emily F.; Khlobystov, Andrei N.; Mellor, Christopher J.; Taniguchi, Takashi; Watanabe, Kenji; Foxon, C. T.; Eaves, L.; Beton, Peter H.; Новиков, С. В.

doi:10.1038/s41598-017-07021-1

Cited by 16 publications

(11 citation statements)

References 58 publications

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“…It is expected that the choice of source and the corresponding operation conditions can impact the properties of the resulting MBE-grown graphene. 28 Finally, for the doped films, a similar trend is observed for samples prepared using growth approaches 1 and 2: a reduction in mobility when boron flux is increased, which is anticipated due to the creation of a higher number of scattering centers in the graphene lattice. However, differently from the charge carrier concentration, no clear distinction between the values obtained for samples prepared by approaches 1 and 2 can be seen.…”

Section: B)supporting

confidence: 55%

Growth of boron-doped few-layer graphene by molecular beam epitaxy

Soares

Nakhaie

Heilmann

et al. 2018

Applied Physics Letters

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We investigated the growth of boron-doped few-layer graphene on α-Al2O3 (0001) substrates by molecular beam epitaxy using two different growth approaches: one where boron was provided during the entire graphene synthesis and the second where boron was provided only during the second half of the graphene growth run. Electrical measurements show a higher p-type carrier concentration for samples fabricated utilizing the second approach, with a remarkable modulation in the carrier concentration of almost two orders of magnitude in comparison to the pristine graphene film. The results concerning the influence of the boron flux at different growth stages of graphene on the electrical and physicochemical properties of the films are presented.

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Section: B)supporting

confidence: 55%

Growth of boron-doped few-layer graphene by molecular beam epitaxy

Soares

Nakhaie

Heilmann

et al. 2018

Applied Physics Letters

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“…The sticking probability of H-atoms with an incident energy of 300 K on a 10 K ASW ice is 0.4 21 , in comparison to the lower value of ∼0.02 for that of graphite 23 . Note that the carbon allotrope formed from the atomic source is determined to be amorphous 24 , and thus the sticking coefficient of H on our carbon surface is likely higher than ∼0.02.…”

Section: Resultsmentioning

confidence: 99%

“…of graphite 23 . Note that the carbon allotrope formed from the atomic source is determined to be amorphous 24 , and thus the sticking coefficient of H on our carbon surface is likely higher than ∼0.02.…”

Section: Resultsmentioning

confidence: 99%

An experimental study of the surface formation of methane in interstellar molecular clouds

et al. 2020

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Methane is one of the simplest stable molecules that is both abundant and widely distributed across space. It is thought to have partial origin from interstellar molecular clouds, which are near the beginning of the star formation cycle. Observational surveys of CH 4 ice towards low-and high-mass young stellar objects showed that much of the CH 4 is expected to be formed by the hydrogenation of C on dust grains, and that CH 4 ice is strongly correlated with solid H 2 O. Yet, this has not been investigated under controlled laboratory conditions, as carbon-atom chemistry of interstellar ice analogues has not been experimentally realized. In this study, we successfully demonstrate with a C-atom beam implemented in an ultrahigh vacuum apparatus the formation of CH 4 ice in two separate co-deposition experiments: C + H on a 10 K surface to mimic CH 4 formation right before H 2 O ice is formed on the dust grain, and C + H + H 2 O on a 10 K surface to mimic CH 4 formed simultaneously with H 2 O ice. We confirm that CH 4 can be formed by the reaction of atomic C and H, and that the CH 4 formation rate is 2 times greater when CH 4 is formed within a H 2 O-rich ice. This is in agreement with the observational finding that interstellar CH 4 and H 2 O form together in the polar ice phase, i.e., when C-and H-atoms simultaneously accrete with O-atoms on dust grains. For the first time, the conditions that lead to interstellar CH 4 (and CD 4 ) ice formation are reported, and can be incorporated into astrochemical models to further constrain CH 4 chemistry in the interstellar medium and in other regions where CH 4 is inherited.

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“…32,33 The original design of the atomic carbon source is found in the work by Krasnokutski and Huisken, 34 and the source discussed in this article is a customized SUKO-A 40 from Dr. Eberl MBE-Komponenten GmbH (MBE), patent number DE 10 2014 009 755 A1. The design of the tantalum tube that is filled with graphite powder can be found in the works by Krasnokutski and Huisken 34 and Albar et al 35 Heating of the tube causes the carbon atom to sublimate and react with tantalum to produce tantalum carbide, resulting in the conversion of molecular carbon into atomic carbon. Thus, the advantage of this source is that it essentially produces C-atoms rather than Cx clusters (<1% C 2 and C 3 molecules).…”

Section: Introductionmentioning

confidence: 99%