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Burning Graphene Layer-by-Layer.

Ermakov VA, Alaferdov AV, Vaz AR, Perim E, Autreto PA, Paupitz R, Galvao DS, Moshkalev SA - Sci Rep (2015)

Bottom Line: In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates.Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification.The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material.

View Article: PubMed Central - PubMed

Affiliation: Center for Semiconductor Components, State University of Campinas, CP 6101, Campinas, SP, 13083-870, Brazil.

ABSTRACT
Graphene, in single layer or multi-layer forms, holds great promise for future electronics and high-temperature applications. Resistance to oxidation, an important property for high-temperature applications, has not yet been extensively investigated. Controlled thinning of multi-layer graphene (MLG), e.g., by plasma or laser processing is another challenge, since the existing methods produce non-uniform thinning or introduce undesirable defects in the basal plane. We report here that heating to extremely high temperatures (exceeding 2000 K) and controllable layer-by-layer burning (thinning) can be achieved by low-power laser processing of suspended high-quality MLG in air in "cold-wall" reactor configuration. In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates. Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification. The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material.

No MeSH data available.


Related in: MedlinePlus

Bottom: Generated gas species during tri- layers graphene burning.First layer has been burned mainly via a complete burning process (CO2 formation). Second layer, under higher temperature, burned via an incomplete burning process (increasing contribution of CO and CO3 formation). Top: Snapshots showing evolution of the top graphitic layer during its burning.
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f3: Bottom: Generated gas species during tri- layers graphene burning.First layer has been burned mainly via a complete burning process (CO2 formation). Second layer, under higher temperature, burned via an incomplete burning process (increasing contribution of CO and CO3 formation). Top: Snapshots showing evolution of the top graphitic layer during its burning.

Mentions: In Fig. 3 we present the number of carbon-carbon bonds for each layer obtained from MD simulations. It is important to note that even though the conditions of simulations (see Methods for details) are significantly different from those for the real experiment (basically, oxygen atoms as oxidation agents instead of mostly molecular oxygen, respectively), the results basically confirm main tendencies observed in the experiment. As can be seen, when the first layer counting significantly drops (indicating the beginning of its effective etching), the count for the second one remains unchanged, meaning that the first layer is being etched while the second layer is still intact (see also Fig. 3). The count for the second layer starts to drop only when the count for the first layer almost reaches zero. The detailed process of graphene etching can be seen in Fig. 4, where we show representative snapshots from MD simulations. A video showing the whole simulation is included as part of Supplementary information.


Burning Graphene Layer-by-Layer.

Ermakov VA, Alaferdov AV, Vaz AR, Perim E, Autreto PA, Paupitz R, Galvao DS, Moshkalev SA - Sci Rep (2015)

Bottom: Generated gas species during tri- layers graphene burning.First layer has been burned mainly via a complete burning process (CO2 formation). Second layer, under higher temperature, burned via an incomplete burning process (increasing contribution of CO and CO3 formation). Top: Snapshots showing evolution of the top graphitic layer during its burning.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4477407&req=5

f3: Bottom: Generated gas species during tri- layers graphene burning.First layer has been burned mainly via a complete burning process (CO2 formation). Second layer, under higher temperature, burned via an incomplete burning process (increasing contribution of CO and CO3 formation). Top: Snapshots showing evolution of the top graphitic layer during its burning.
Mentions: In Fig. 3 we present the number of carbon-carbon bonds for each layer obtained from MD simulations. It is important to note that even though the conditions of simulations (see Methods for details) are significantly different from those for the real experiment (basically, oxygen atoms as oxidation agents instead of mostly molecular oxygen, respectively), the results basically confirm main tendencies observed in the experiment. As can be seen, when the first layer counting significantly drops (indicating the beginning of its effective etching), the count for the second one remains unchanged, meaning that the first layer is being etched while the second layer is still intact (see also Fig. 3). The count for the second layer starts to drop only when the count for the first layer almost reaches zero. The detailed process of graphene etching can be seen in Fig. 4, where we show representative snapshots from MD simulations. A video showing the whole simulation is included as part of Supplementary information.

Bottom Line: In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates.Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification.The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material.

View Article: PubMed Central - PubMed

Affiliation: Center for Semiconductor Components, State University of Campinas, CP 6101, Campinas, SP, 13083-870, Brazil.

ABSTRACT
Graphene, in single layer or multi-layer forms, holds great promise for future electronics and high-temperature applications. Resistance to oxidation, an important property for high-temperature applications, has not yet been extensively investigated. Controlled thinning of multi-layer graphene (MLG), e.g., by plasma or laser processing is another challenge, since the existing methods produce non-uniform thinning or introduce undesirable defects in the basal plane. We report here that heating to extremely high temperatures (exceeding 2000 K) and controllable layer-by-layer burning (thinning) can be achieved by low-power laser processing of suspended high-quality MLG in air in "cold-wall" reactor configuration. In contrast, localized laser heating of supported samples results in non-uniform graphene burning at much higher rates. Fully atomistic molecular dynamics simulations were also performed to reveal details of oxidation mechanisms leading to uniform layer-by-layer graphene gasification. The extraordinary resistance of MLG to oxidation paves the way to novel high-temperature applications as continuum light source or scaffolding material.

No MeSH data available.


Related in: MedlinePlus