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Fabrication of graphene films with high transparent conducting characteristics.

Ma X, Zhang H - Nanoscale Res Lett (2013)

Bottom Line: It was found that the graphene films present excellent electrical conductivity with high transparency.The conductivity is up to 1,240 S/cm, the sheet resistance is lower than 1 kΩ/sq, and the transparency is well over 85% in the visible wavelength range of 400 to 800 nm, showing that the graphene films have very low resistivity and superior transparency and completely satisfy the need for transparent conductors.PACS: 61.48.+c, 78.67.Pt, 68.37.Hk, 68.65.Ac.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Mathematics and Physics, Suzhou University of Science and Technology, 1# Kerui Road, Suzhou, Jiangsu 215009, China. maxy@mail.usts.edu.cn.

ABSTRACT
We present a study on the transparent conducting characteristics of graphene-based films prepared by means of rapid chemical vapor deposition. The graphene films were grown on quartz slides with a CH4/Ar mixed gas under a constant flow at 950°C and then annealed at 1,000°C. It was found that the graphene films present excellent electrical conductivity with high transparency. The conductivity is up to 1,240 S/cm, the sheet resistance is lower than 1 kΩ/sq, and the transparency is well over 85% in the visible wavelength range of 400 to 800 nm, showing that the graphene films have very low resistivity and superior transparency and completely satisfy the need for transparent conductors. These properties can be used in many applications, such as transparent conductor films for touch panels. PACS: 61.48.+c, 78.67.Pt, 68.37.Hk, 68.65.Ac.

No MeSH data available.


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Relation of thickness and deposition time, electron mobility, conductivity, and sheet resistance. (a) The relation of thickness of the graphene films with deposition time. (b) The dependences of electron mobility and conductivity on graphene thickness. (c) The sheet resistance Rs changing with the thickness.
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Figure 6: Relation of thickness and deposition time, electron mobility, conductivity, and sheet resistance. (a) The relation of thickness of the graphene films with deposition time. (b) The dependences of electron mobility and conductivity on graphene thickness. (c) The sheet resistance Rs changing with the thickness.

Mentions: The thickness of the graphene films with deposition time is shown in Figure 6a. We can see that the thickness linearly increases with time. Then we investigated the electron mobility, conductivity, and sheet resistance with the thickness of the graphene films, as shown in Figure 6b,c. The electron mobility is 2.3 × 102, 5.1 × 104, and 9.5 × 104 cm2/V/s for 1, 3, and 5 min samples, respectively. The latter two values are very close to the known ideal value of 2 × 105 cm2/V/s [3,4]. The electron mobility and conductivity initially linearly increase and then gradually reach saturation with thickness. The results are consistent with the I-V behaviors. For a low thickness value, the graphene does not form a continuous film but many islands, which collect and fuse each other with deposition time, leading to the mobility and conductivity increasing linearly and then up to their ultimate values. The conductivity of the graphene film with a 7-nm thickness is about 1,240 S/cm, superior to that of Levendorf et al. [24] who reported 102 S/cm for the same thickness. The sheet resistance Rs in Figure 6c has a reversed tendency with thickness, i.e., initially significantly drops and slowly decreases. Especially, Rs drops from 105 to 103 Ω/sq as the thickness increases from 2 to 7 nm. The typical Rs of the ITO film is 103 ~ 106 Ω/sq. Hence, the Rs of about 103 Ω/sq shows that the deposited graphene has very low resistivity, satisfying the need for transparent conducting films. This value is about two times smaller than that of Wang et al. [27] who reported 2 kΩ/sq and very close to 350 Ω/sq of graphene deposited on copper then transferred on SiO2[22]. Wu et al. [11] reported that a graphene film with a thickness of 7 nm and a sheet resistance of 800 Ω/sq was used as a good transparent conductor of an OLED.


Fabrication of graphene films with high transparent conducting characteristics.

Ma X, Zhang H - Nanoscale Res Lett (2013)

Relation of thickness and deposition time, electron mobility, conductivity, and sheet resistance. (a) The relation of thickness of the graphene films with deposition time. (b) The dependences of electron mobility and conductivity on graphene thickness. (c) The sheet resistance Rs changing with the thickness.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4016024&req=5

Figure 6: Relation of thickness and deposition time, electron mobility, conductivity, and sheet resistance. (a) The relation of thickness of the graphene films with deposition time. (b) The dependences of electron mobility and conductivity on graphene thickness. (c) The sheet resistance Rs changing with the thickness.
Mentions: The thickness of the graphene films with deposition time is shown in Figure 6a. We can see that the thickness linearly increases with time. Then we investigated the electron mobility, conductivity, and sheet resistance with the thickness of the graphene films, as shown in Figure 6b,c. The electron mobility is 2.3 × 102, 5.1 × 104, and 9.5 × 104 cm2/V/s for 1, 3, and 5 min samples, respectively. The latter two values are very close to the known ideal value of 2 × 105 cm2/V/s [3,4]. The electron mobility and conductivity initially linearly increase and then gradually reach saturation with thickness. The results are consistent with the I-V behaviors. For a low thickness value, the graphene does not form a continuous film but many islands, which collect and fuse each other with deposition time, leading to the mobility and conductivity increasing linearly and then up to their ultimate values. The conductivity of the graphene film with a 7-nm thickness is about 1,240 S/cm, superior to that of Levendorf et al. [24] who reported 102 S/cm for the same thickness. The sheet resistance Rs in Figure 6c has a reversed tendency with thickness, i.e., initially significantly drops and slowly decreases. Especially, Rs drops from 105 to 103 Ω/sq as the thickness increases from 2 to 7 nm. The typical Rs of the ITO film is 103 ~ 106 Ω/sq. Hence, the Rs of about 103 Ω/sq shows that the deposited graphene has very low resistivity, satisfying the need for transparent conducting films. This value is about two times smaller than that of Wang et al. [27] who reported 2 kΩ/sq and very close to 350 Ω/sq of graphene deposited on copper then transferred on SiO2[22]. Wu et al. [11] reported that a graphene film with a thickness of 7 nm and a sheet resistance of 800 Ω/sq was used as a good transparent conductor of an OLED.

Bottom Line: It was found that the graphene films present excellent electrical conductivity with high transparency.The conductivity is up to 1,240 S/cm, the sheet resistance is lower than 1 kΩ/sq, and the transparency is well over 85% in the visible wavelength range of 400 to 800 nm, showing that the graphene films have very low resistivity and superior transparency and completely satisfy the need for transparent conductors.PACS: 61.48.+c, 78.67.Pt, 68.37.Hk, 68.65.Ac.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Mathematics and Physics, Suzhou University of Science and Technology, 1# Kerui Road, Suzhou, Jiangsu 215009, China. maxy@mail.usts.edu.cn.

ABSTRACT
We present a study on the transparent conducting characteristics of graphene-based films prepared by means of rapid chemical vapor deposition. The graphene films were grown on quartz slides with a CH4/Ar mixed gas under a constant flow at 950°C and then annealed at 1,000°C. It was found that the graphene films present excellent electrical conductivity with high transparency. The conductivity is up to 1,240 S/cm, the sheet resistance is lower than 1 kΩ/sq, and the transparency is well over 85% in the visible wavelength range of 400 to 800 nm, showing that the graphene films have very low resistivity and superior transparency and completely satisfy the need for transparent conductors. These properties can be used in many applications, such as transparent conductor films for touch panels. PACS: 61.48.+c, 78.67.Pt, 68.37.Hk, 68.65.Ac.

No MeSH data available.


Related in: MedlinePlus