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Atomic Layer Deposition of ZnO on Multi-walled Carbon Nanotubes and Its Use for Synthesis of CNT-ZnO Heterostructures.

Li XL, Li C, Zhang Y, Chu DP, Milne WI, Fan HJ - Nanoscale Res Lett (2010)

Bottom Line: In this article, direct coating of ZnO on PECVD-grown multi-walled carbon nanotubes (MWCNTs) is achieved using atomic layer deposition (ALD).The ZnO layer has a good crystalline quality as indicated by Raman and photoluminescence (PL) measurements.We also show that such ZnO layer can be used as seed layer for subsequent hydrothermal growth of ZnO nanorods, resulting in branched CNT-inorganic hybrid nanostructures.

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ABSTRACT
In this article, direct coating of ZnO on PECVD-grown multi-walled carbon nanotubes (MWCNTs) is achieved using atomic layer deposition (ALD). Transmission electron microscopy investigation shows that the deposited ZnO shell is continuous and uniform, in contrast to the previously reported particle morphology. The ZnO layer has a good crystalline quality as indicated by Raman and photoluminescence (PL) measurements. We also show that such ZnO layer can be used as seed layer for subsequent hydrothermal growth of ZnO nanorods, resulting in branched CNT-inorganic hybrid nanostructures. Potentially, this method can also apply to the fabrication of ZnO-based hybrid nanostructures on other carbon nanomaterials.

No MeSH data available.


Raman spectrum of CNTs before (a) and after (b) ALD of ZnO. Inset: Raman spectrum in the range of 150–650 cm−1 of ZnO-coated CNTs
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Figure 2: Raman spectrum of CNTs before (a) and after (b) ALD of ZnO. Inset: Raman spectrum in the range of 150–650 cm−1 of ZnO-coated CNTs

Mentions: There are several factors that affect the morphology of the ALD ZnO shell on CNTs. The first one is the surface configuration of the CNTs. As a micromolecular form of carbon, CNT can be regarded as graphitic layers (sp2-hybridized carbon atoms) rolled up into a cylindrical form. A perfect CNT is chemically inert. However, there generally exist defects on the tube wall, such as bending in the nanotube, the finite size of crystalline domains, sp3-hybridized bonds, or functional groups created by oxidation [17,18]. These defects or functional groups make the CNT surface reactive to the atomic species of an ALD precursor. The Raman spectrum of our PECVD MWCNTs (Fig. 2 curve a) shows a strong D band, indicating the existence of defects on the tube wall. Compared to MWCNTs, the surfaces of the single-walled carbon nanotubes (SWCNTs) are known to have less structural defects or impurity sites on the tube walls. This is the reason why ALD on SWCNTs is generally more challenging than on MWCNTs. The same argument holds true for deposition on graphene. In the ALD work by Min et al. [10], ZnO particles were deposited on the SWCNTs. It is most likely that the nanoparticles were formed selectively on the defective sites or impurities on the nanotubes wall, which provide chemisorptions sites for DEZ molecules.


Atomic Layer Deposition of ZnO on Multi-walled Carbon Nanotubes and Its Use for Synthesis of CNT-ZnO Heterostructures.

Li XL, Li C, Zhang Y, Chu DP, Milne WI, Fan HJ - Nanoscale Res Lett (2010)

Raman spectrum of CNTs before (a) and after (b) ALD of ZnO. Inset: Raman spectrum in the range of 150–650 cm−1 of ZnO-coated CNTs
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2964460&req=5

Figure 2: Raman spectrum of CNTs before (a) and after (b) ALD of ZnO. Inset: Raman spectrum in the range of 150–650 cm−1 of ZnO-coated CNTs
Mentions: There are several factors that affect the morphology of the ALD ZnO shell on CNTs. The first one is the surface configuration of the CNTs. As a micromolecular form of carbon, CNT can be regarded as graphitic layers (sp2-hybridized carbon atoms) rolled up into a cylindrical form. A perfect CNT is chemically inert. However, there generally exist defects on the tube wall, such as bending in the nanotube, the finite size of crystalline domains, sp3-hybridized bonds, or functional groups created by oxidation [17,18]. These defects or functional groups make the CNT surface reactive to the atomic species of an ALD precursor. The Raman spectrum of our PECVD MWCNTs (Fig. 2 curve a) shows a strong D band, indicating the existence of defects on the tube wall. Compared to MWCNTs, the surfaces of the single-walled carbon nanotubes (SWCNTs) are known to have less structural defects or impurity sites on the tube walls. This is the reason why ALD on SWCNTs is generally more challenging than on MWCNTs. The same argument holds true for deposition on graphene. In the ALD work by Min et al. [10], ZnO particles were deposited on the SWCNTs. It is most likely that the nanoparticles were formed selectively on the defective sites or impurities on the nanotubes wall, which provide chemisorptions sites for DEZ molecules.

Bottom Line: In this article, direct coating of ZnO on PECVD-grown multi-walled carbon nanotubes (MWCNTs) is achieved using atomic layer deposition (ALD).The ZnO layer has a good crystalline quality as indicated by Raman and photoluminescence (PL) measurements.We also show that such ZnO layer can be used as seed layer for subsequent hydrothermal growth of ZnO nanorods, resulting in branched CNT-inorganic hybrid nanostructures.

View Article: PubMed Central - HTML - PubMed

ABSTRACT
In this article, direct coating of ZnO on PECVD-grown multi-walled carbon nanotubes (MWCNTs) is achieved using atomic layer deposition (ALD). Transmission electron microscopy investigation shows that the deposited ZnO shell is continuous and uniform, in contrast to the previously reported particle morphology. The ZnO layer has a good crystalline quality as indicated by Raman and photoluminescence (PL) measurements. We also show that such ZnO layer can be used as seed layer for subsequent hydrothermal growth of ZnO nanorods, resulting in branched CNT-inorganic hybrid nanostructures. Potentially, this method can also apply to the fabrication of ZnO-based hybrid nanostructures on other carbon nanomaterials.

No MeSH data available.