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Revelation of graphene-Au for direct write deposition and characterization.

Bhandari S, Deepa M, Joshi AG, Saxena AP, Srivastava AK - Nanoscale Res Lett (2011)

Bottom Line: Graphene nanosheets were prepared using a modified Hummer's method, and Au-graphene nanocomposites were fabricated by in situ reduction of a gold salt.Scanning helium ion microscopy (HIM) technique was employed to demonstrate direct write deposition on graphene by lettering with gaps down to 7 nm within the chamber of the microscope.Bare graphene and graphene-gold nanocomposites were further characterized in terms of their composition and optical and electrical properties.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Physical Laboratory, Council of Scientific and Industrial Research, Dr, K,S, Krishnan Road, New Delhi, 110 012, India. aks@nplindia.ernet.in.

ABSTRACT
Graphene nanosheets were prepared using a modified Hummer's method, and Au-graphene nanocomposites were fabricated by in situ reduction of a gold salt. The as-produced graphene was characterized by X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy (HR-TEM). In particular, the HR-TEM demonstrated the layered crystallites of graphene with fringe spacing of about 0.32 nm in individual sheets and the ultrafine facetted structure of about 20 to 50 nm of Au particles in graphene composite. Scanning helium ion microscopy (HIM) technique was employed to demonstrate direct write deposition on graphene by lettering with gaps down to 7 nm within the chamber of the microscope. Bare graphene and graphene-gold nanocomposites were further characterized in terms of their composition and optical and electrical properties.

No MeSH data available.


I-V characteristics of Au-graphene and blank acid-functionalized graphene.
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Figure 6: I-V characteristics of Au-graphene and blank acid-functionalized graphene.

Mentions: The I-V characteristics of Au-graphene and functionalized graphene were recorded in the following configuration: SnO2:F/Au-graphene/aluminum as shown in Figure 6 where respective solutions were drop casted on the SnO2:F-coated glass substrates. The AuNPs decoration was having a beneficial effect on the electronic conductivity of graphene. Both the films show ohmic contact with the substrate in 0 to +1 V potential region as can be seen from the linear variation of current with applied bias. For the Au-graphene composite, the conductivity was determined to be 0.49 S cm-1 which is much higher than blank functionalized graphene film where the value was estimated to be 0.07 S cm-1 which validates the role of interaction with AuNPs in the enhancement of conductivity. In the literature, the value of pristine graphene has been reported to be 0.2 S cm-1 [9]. Here, probably due to functionalization, the value is lower. In Au-graphene, enhanced coupling occurred between AuNPs as they attached themselves onto the defect sites of graphene surface, hereby increasing the charge transfer between the two. Functional groups present on the graphene sheets served as anchors for adsorption of nanoparticles and the positively charged AuNPs as depicted earlier in XPS could easily adsorb on these negative sheets through electrostatic attraction. Moreover, even the inherent electronic conductivity of the metal NPs are higher and all these attribute to the increased conductivity in the Au-graphene nanocomposite.


Revelation of graphene-Au for direct write deposition and characterization.

Bhandari S, Deepa M, Joshi AG, Saxena AP, Srivastava AK - Nanoscale Res Lett (2011)

I-V characteristics of Au-graphene and blank acid-functionalized graphene.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211841&req=5

Figure 6: I-V characteristics of Au-graphene and blank acid-functionalized graphene.
Mentions: The I-V characteristics of Au-graphene and functionalized graphene were recorded in the following configuration: SnO2:F/Au-graphene/aluminum as shown in Figure 6 where respective solutions were drop casted on the SnO2:F-coated glass substrates. The AuNPs decoration was having a beneficial effect on the electronic conductivity of graphene. Both the films show ohmic contact with the substrate in 0 to +1 V potential region as can be seen from the linear variation of current with applied bias. For the Au-graphene composite, the conductivity was determined to be 0.49 S cm-1 which is much higher than blank functionalized graphene film where the value was estimated to be 0.07 S cm-1 which validates the role of interaction with AuNPs in the enhancement of conductivity. In the literature, the value of pristine graphene has been reported to be 0.2 S cm-1 [9]. Here, probably due to functionalization, the value is lower. In Au-graphene, enhanced coupling occurred between AuNPs as they attached themselves onto the defect sites of graphene surface, hereby increasing the charge transfer between the two. Functional groups present on the graphene sheets served as anchors for adsorption of nanoparticles and the positively charged AuNPs as depicted earlier in XPS could easily adsorb on these negative sheets through electrostatic attraction. Moreover, even the inherent electronic conductivity of the metal NPs are higher and all these attribute to the increased conductivity in the Au-graphene nanocomposite.

Bottom Line: Graphene nanosheets were prepared using a modified Hummer's method, and Au-graphene nanocomposites were fabricated by in situ reduction of a gold salt.Scanning helium ion microscopy (HIM) technique was employed to demonstrate direct write deposition on graphene by lettering with gaps down to 7 nm within the chamber of the microscope.Bare graphene and graphene-gold nanocomposites were further characterized in terms of their composition and optical and electrical properties.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Physical Laboratory, Council of Scientific and Industrial Research, Dr, K,S, Krishnan Road, New Delhi, 110 012, India. aks@nplindia.ernet.in.

ABSTRACT
Graphene nanosheets were prepared using a modified Hummer's method, and Au-graphene nanocomposites were fabricated by in situ reduction of a gold salt. The as-produced graphene was characterized by X-ray photoelectron spectroscopy, ultraviolet-visible spectroscopy, scanning electron microscopy, and high-resolution transmission electron microscopy (HR-TEM). In particular, the HR-TEM demonstrated the layered crystallites of graphene with fringe spacing of about 0.32 nm in individual sheets and the ultrafine facetted structure of about 20 to 50 nm of Au particles in graphene composite. Scanning helium ion microscopy (HIM) technique was employed to demonstrate direct write deposition on graphene by lettering with gaps down to 7 nm within the chamber of the microscope. Bare graphene and graphene-gold nanocomposites were further characterized in terms of their composition and optical and electrical properties.

No MeSH data available.