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Reliable processing of graphene using metal etchmasks.

Kumar S, Peltekis N, Lee K, Kim HY, Duesberg GS - Nanoscale Res Lett (2011)

Bottom Line: We introduce a metal etch mask which minimises these problems.The high quality of graphene is shown by Raman and XPS spectroscopy as well as electrical measurements.The process is of high value for applications, as it improves the processability of graphene using high-throughput lithography and etching techniques.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Chemistry, Trinity College Dublin, Ireland. duesberg@tcd.ie.

ABSTRACT
Graphene exhibits exciting properties which make it an appealing candidate for use in electronic devices. Reliable processes for device fabrication are crucial prerequisites for this. We developed a large area of CVD synthesis and transfer of graphene films. With patterning of these graphene layers using standard photoresist masks, we are able to produce arrays of gated graphene devices with four point contacts. The etching and lift off process poses problems because of delamination and contamination due to polymer residues when using standard resists. We introduce a metal etch mask which minimises these problems. The high quality of graphene is shown by Raman and XPS spectroscopy as well as electrical measurements. The process is of high value for applications, as it improves the processability of graphene using high-throughput lithography and etching techniques.

No MeSH data available.


Characterisation of as transferred graphene on SiO2 substrates. On left XPS spectrum shows good quality graphene, on right AFM image shows presence of large flakes of graphene with some contamination (marked by circles) and cracks (marked by rectangles). The Raman spectrum of monolayer graphene obtained from the sample is shown in inset.
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Figure 1: Characterisation of as transferred graphene on SiO2 substrates. On left XPS spectrum shows good quality graphene, on right AFM image shows presence of large flakes of graphene with some contamination (marked by circles) and cracks (marked by rectangles). The Raman spectrum of monolayer graphene obtained from the sample is shown in inset.

Mentions: CVD-grown films on Cu of typically 1 × 1 cm2 were transferred onto SiO2 and characterised by XPS and AFM. The XPS spectrum is shown in Figure 1 (left). The main fit has the characteristic asymmetry of graphitic structure. The second biggest fit accounts for amorphous, aliphatic and sp3 bonds, indicating that some contaminants were residing on graphene. An AFM scan (Figure 1, right) of the graphene after transfer to the SiO2 shows some cracked regions and impurities on the graphene, partly in big clusters, indicating polymer fragments coming from the transfer process. The minimum height of the flakes was between 1 and 2 nm, indicating mono- or bilayer graphene. The large 2D (approx. 2665 cm-1) to G (approx. 1580 cm-1) peaks ratio shown in the inset supports this. The Raman spectrum also shows some defects as a small visible D peak (approx. 1350 cm-1). This could also indicate the presence of impurities.


Reliable processing of graphene using metal etchmasks.

Kumar S, Peltekis N, Lee K, Kim HY, Duesberg GS - Nanoscale Res Lett (2011)

Characterisation of as transferred graphene on SiO2 substrates. On left XPS spectrum shows good quality graphene, on right AFM image shows presence of large flakes of graphene with some contamination (marked by circles) and cracks (marked by rectangles). The Raman spectrum of monolayer graphene obtained from the sample is shown in inset.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211484&req=5

Figure 1: Characterisation of as transferred graphene on SiO2 substrates. On left XPS spectrum shows good quality graphene, on right AFM image shows presence of large flakes of graphene with some contamination (marked by circles) and cracks (marked by rectangles). The Raman spectrum of monolayer graphene obtained from the sample is shown in inset.
Mentions: CVD-grown films on Cu of typically 1 × 1 cm2 were transferred onto SiO2 and characterised by XPS and AFM. The XPS spectrum is shown in Figure 1 (left). The main fit has the characteristic asymmetry of graphitic structure. The second biggest fit accounts for amorphous, aliphatic and sp3 bonds, indicating that some contaminants were residing on graphene. An AFM scan (Figure 1, right) of the graphene after transfer to the SiO2 shows some cracked regions and impurities on the graphene, partly in big clusters, indicating polymer fragments coming from the transfer process. The minimum height of the flakes was between 1 and 2 nm, indicating mono- or bilayer graphene. The large 2D (approx. 2665 cm-1) to G (approx. 1580 cm-1) peaks ratio shown in the inset supports this. The Raman spectrum also shows some defects as a small visible D peak (approx. 1350 cm-1). This could also indicate the presence of impurities.

Bottom Line: We introduce a metal etch mask which minimises these problems.The high quality of graphene is shown by Raman and XPS spectroscopy as well as electrical measurements.The process is of high value for applications, as it improves the processability of graphene using high-throughput lithography and etching techniques.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Chemistry, Trinity College Dublin, Ireland. duesberg@tcd.ie.

ABSTRACT
Graphene exhibits exciting properties which make it an appealing candidate for use in electronic devices. Reliable processes for device fabrication are crucial prerequisites for this. We developed a large area of CVD synthesis and transfer of graphene films. With patterning of these graphene layers using standard photoresist masks, we are able to produce arrays of gated graphene devices with four point contacts. The etching and lift off process poses problems because of delamination and contamination due to polymer residues when using standard resists. We introduce a metal etch mask which minimises these problems. The high quality of graphene is shown by Raman and XPS spectroscopy as well as electrical measurements. The process is of high value for applications, as it improves the processability of graphene using high-throughput lithography and etching techniques.

No MeSH data available.