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The deviation of growth model for transparent conductive graphene.

Chan SH, Chen JW, Chen HP, Wei HS, Li MC, Chen SH, Lee CC, Kuo CC - Nanoscale Res Lett (2014)

Bottom Line: The Raman intensity ratio of the G-peak to the 2D peak of the graphene film was as high as ~4 when the hydrogen flow rate was 30 sccm.The fitting curve obtained by the deviation equation of growth model closely matches the data.We believe that under the same conditions and with the same setup, the presented growth model can help manufacturers and academics to predict graphene growth time more accurately.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Optics and Photonics/Thin Film Technology Center, National Central University, 300 Chung-Da Rd, Chung-Li 32001, Taiwan.

ABSTRACT
An approximate growth model was employed to predict the time required to grow a graphene film by chemical vapor deposition (CVD). Monolayer graphene films were synthesized on Cu foil at various hydrogen flow rates from 10 to 50 sccm. The sheet resistance of the graphene film was 310Ω/□ and the optical transmittance was 97.7%. The Raman intensity ratio of the G-peak to the 2D peak of the graphene film was as high as ~4 when the hydrogen flow rate was 30 sccm. The fitting curve obtained by the deviation equation of growth model closely matches the data. We believe that under the same conditions and with the same setup, the presented growth model can help manufacturers and academics to predict graphene growth time more accurately.

No MeSH data available.


Results of growth model and SEM image. Results of growth model with growth time of (a) t1 and (b) t2. (c) SEM image of hexagonal graphene domain with hydrogen flow rate of 30 sccm.(d) The deviation of growth model for graphene domain.
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Figure 3: Results of growth model and SEM image. Results of growth model with growth time of (a) t1 and (b) t2. (c) SEM image of hexagonal graphene domain with hydrogen flow rate of 30 sccm.(d) The deviation of growth model for graphene domain.

Mentions: The number of graphene layers, the shape, and the nucleation density were significantly influenced by the surface roughness of Cu foil. Figure 1a,c presents AFM images of the reduction of the rolling marks on the Cu foil by electropolishing. The domain density of graphene clearly declined from Figure 1b-d, and the graphene morphology became star-shaped under hydrogen at a 1flow rate of 20 sccm. In the latter experiments, the electropolishing of Cu foils were applied for growing graphene films. To synthesize a larger graphene domain, experiments were conducted in which the hydrogen flow rate was increased from 10 to 50 sccm, and the graphene domain density is calculated, as displayed in Figure 2. A previous investigation revealed that the hydrogen flow rate importantly affects the graphene growth mechanism, owing to the etch effect and its effect on the graphene domain density. The density of graphene nuclei is reduced as the hydrogen flow rate is increased. The hydrogen flow rate also affects the morphology of graphene. In this case, the graphene had a hexagonal shape when the hydrogen flow rate was 30 sccm, as shown in Figure 3c. A growth model to elucidate the rate of graphene domain growth was proposed. If the graphene domain is circular, then this model allows the easy calculation of the difference between the graphene domain sizes at two growth times. Figure 3 displays the derivation of the growth model. Figure 3a,b schematically depicts the growth of the graphene domains from growth time t1 to t2. Figure 3d presents the growth model in detail, where L is the circumference of graphene domain; A is the mean area of the grown domains, and the r is the average radius of the domains. Now, an area factor is sought such that


The deviation of growth model for transparent conductive graphene.

Chan SH, Chen JW, Chen HP, Wei HS, Li MC, Chen SH, Lee CC, Kuo CC - Nanoscale Res Lett (2014)

Results of growth model and SEM image. Results of growth model with growth time of (a) t1 and (b) t2. (c) SEM image of hexagonal graphene domain with hydrogen flow rate of 30 sccm.(d) The deviation of growth model for graphene domain.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4214604&req=5

Figure 3: Results of growth model and SEM image. Results of growth model with growth time of (a) t1 and (b) t2. (c) SEM image of hexagonal graphene domain with hydrogen flow rate of 30 sccm.(d) The deviation of growth model for graphene domain.
Mentions: The number of graphene layers, the shape, and the nucleation density were significantly influenced by the surface roughness of Cu foil. Figure 1a,c presents AFM images of the reduction of the rolling marks on the Cu foil by electropolishing. The domain density of graphene clearly declined from Figure 1b-d, and the graphene morphology became star-shaped under hydrogen at a 1flow rate of 20 sccm. In the latter experiments, the electropolishing of Cu foils were applied for growing graphene films. To synthesize a larger graphene domain, experiments were conducted in which the hydrogen flow rate was increased from 10 to 50 sccm, and the graphene domain density is calculated, as displayed in Figure 2. A previous investigation revealed that the hydrogen flow rate importantly affects the graphene growth mechanism, owing to the etch effect and its effect on the graphene domain density. The density of graphene nuclei is reduced as the hydrogen flow rate is increased. The hydrogen flow rate also affects the morphology of graphene. In this case, the graphene had a hexagonal shape when the hydrogen flow rate was 30 sccm, as shown in Figure 3c. A growth model to elucidate the rate of graphene domain growth was proposed. If the graphene domain is circular, then this model allows the easy calculation of the difference between the graphene domain sizes at two growth times. Figure 3 displays the derivation of the growth model. Figure 3a,b schematically depicts the growth of the graphene domains from growth time t1 to t2. Figure 3d presents the growth model in detail, where L is the circumference of graphene domain; A is the mean area of the grown domains, and the r is the average radius of the domains. Now, an area factor is sought such that

Bottom Line: The Raman intensity ratio of the G-peak to the 2D peak of the graphene film was as high as ~4 when the hydrogen flow rate was 30 sccm.The fitting curve obtained by the deviation equation of growth model closely matches the data.We believe that under the same conditions and with the same setup, the presented growth model can help manufacturers and academics to predict graphene growth time more accurately.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Optics and Photonics/Thin Film Technology Center, National Central University, 300 Chung-Da Rd, Chung-Li 32001, Taiwan.

ABSTRACT
An approximate growth model was employed to predict the time required to grow a graphene film by chemical vapor deposition (CVD). Monolayer graphene films were synthesized on Cu foil at various hydrogen flow rates from 10 to 50 sccm. The sheet resistance of the graphene film was 310Ω/□ and the optical transmittance was 97.7%. The Raman intensity ratio of the G-peak to the 2D peak of the graphene film was as high as ~4 when the hydrogen flow rate was 30 sccm. The fitting curve obtained by the deviation equation of growth model closely matches the data. We believe that under the same conditions and with the same setup, the presented growth model can help manufacturers and academics to predict graphene growth time more accurately.

No MeSH data available.