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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.


Core level spectra of Au-graphene nanocomposite. With solid lines signifying the deconvoluted contributions of (a) C1s, (b) O1s, (c) Au4f and (d) N1s.
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Figure 2: Core level spectra of Au-graphene nanocomposite. With solid lines signifying the deconvoluted contributions of (a) C1s, (b) O1s, (c) Au4f and (d) N1s.

Mentions: The formation of stabilized Au-graphene nanocomposite was further confirmed by the XPS spectra as shown in Figure 2. Various compendia of peak attributions of C1s and O1s are listed in Table 1. C1s complex envelope is constituted of five contributions confirming the acid functionalizing of the graphene. Peak at 531.1 eV in O1s spectra owing to C-O-Au bond confirms the stabilized Au-graphene nanocomposite. The N1s peak at 403.5 eV shows clearly the functionalization of graphene by acid treatment. The signature of Au doublet was found with two distinct state of Au(4f5/2) and Au(4f7/2) [25] due to the spit-orbit splitting. The binding energy values are somewhat lower. Similar trend was observed by Li et al. [23] for Ag/graphene nanocomposites where the effect was attributed to electron transfer from Ag to graphene due to smaller wave function of Ag than graphene [26,27]. Interaction between Au and C=O of graphene also contributes to the electron transfer [28], and the result corroborates with that of UV results. The binding energy difference between the two states found 3.7 eV, which confirms the Au in charged Au+ state. Deconvolution was performed on C(1s), O(1s) and Au(4f) XPS core spectra are shown in Figure 2. Au(4f) deconvoluted spectra was composed of four peaks (Figure 2c). The resolved peaks related to Au0 (81.8 and 85.3 eV) exhibit the metallic nature of Au, while Au+ state (83.7 and 87.4 eV) probably due to the interaction with the negatively charged graphene around Au induces a positive charge. The contribution of various spices of core level spectra is listed in Table 1.


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

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

Core level spectra of Au-graphene nanocomposite. With solid lines signifying the deconvoluted contributions of (a) C1s, (b) O1s, (c) Au4f and (d) N1s.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Core level spectra of Au-graphene nanocomposite. With solid lines signifying the deconvoluted contributions of (a) C1s, (b) O1s, (c) Au4f and (d) N1s.
Mentions: The formation of stabilized Au-graphene nanocomposite was further confirmed by the XPS spectra as shown in Figure 2. Various compendia of peak attributions of C1s and O1s are listed in Table 1. C1s complex envelope is constituted of five contributions confirming the acid functionalizing of the graphene. Peak at 531.1 eV in O1s spectra owing to C-O-Au bond confirms the stabilized Au-graphene nanocomposite. The N1s peak at 403.5 eV shows clearly the functionalization of graphene by acid treatment. The signature of Au doublet was found with two distinct state of Au(4f5/2) and Au(4f7/2) [25] due to the spit-orbit splitting. The binding energy values are somewhat lower. Similar trend was observed by Li et al. [23] for Ag/graphene nanocomposites where the effect was attributed to electron transfer from Ag to graphene due to smaller wave function of Ag than graphene [26,27]. Interaction between Au and C=O of graphene also contributes to the electron transfer [28], and the result corroborates with that of UV results. The binding energy difference between the two states found 3.7 eV, which confirms the Au in charged Au+ state. Deconvolution was performed on C(1s), O(1s) and Au(4f) XPS core spectra are shown in Figure 2. Au(4f) deconvoluted spectra was composed of four peaks (Figure 2c). The resolved peaks related to Au0 (81.8 and 85.3 eV) exhibit the metallic nature of Au, while Au+ state (83.7 and 87.4 eV) probably due to the interaction with the negatively charged graphene around Au induces a positive charge. The contribution of various spices of core level spectra is listed in Table 1.

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.