Dragana D. Tošić

Monolayer graphene films through nickel catalyzed transformation of fullerol and graphene quantum dots: a Raman spectroscopy study

In this paper we present synthesis of monolayer graphene islands. These films are deposited through nickel catalyzed transformation of fullerol and graphene quantum dots. Carbon doped nickel films are produced by autocatalytic chemical deposition. Upon rapid thermal annealing, graphene films are formed. Different characterization techniques are applied: Raman spectroscopy, scanning electron and atomic force microscopy. Raman spectroscopy analysis confirmed the formation of monolayer graphene films. Microscopy analysis revealed formation of monolayer islands.

Raman spectroscopy of graphene nanoribbons synthesized by longitudinal unzipping of multiwall carbon nanotubes

Graphene nanoribbons (GNRs) were synthesized by longitudinal unzipping of multiwall carbon nanotubes (MWCNTs), and changes in Raman spectra were followed. Transmission electron microscopy was used to investigate the longitudinal opening of carbon nanotubes. Height and height profiles of GNRs are observed by atomic force microscopy. Considering that GNRs are carbon-based material, we conducted a detailed Raman spectroscopy study of this new material. Raman measurements were performed at three different laser excitational lines: 532, 633 and 785 nm. We noticed a considerable increase in the ratio between D and G bands compared to the same parameter for MWCNTs. The contribution of the edge structure is much higher in GNRs than in the structure of pristine MWCNTs, which is a main reason for the high increase in structural disorder. It was also noticed that the intensity of the 2D band was significantly lower compared to the same band in the Raman spectra of pristine MWCNTs.

Surface modification of single-wall carbon nanotube thin films irradiated by microwaves: a Raman spectroscopy study

In this work, we present the results of a Raman spectroscopy study of single-wall carbon nanotube (SWCNT) thin films treated with microwave irradiation. SWCNT thin films were deposited by the vacuum filtration method and transferred onto alumina substrate. These thin films were exposed to microwave irradiation of 25 and 250 W at 2.45 GHz. All samples were characterized by Raman spectroscopy and atomic force microscopy. Raman spectroscopy analysis showed that there was neither selective destruction of metallic nor semiconducting nanotubes. It was noticed that samples were heated only during microwave irradiation at 250 W. The major effect of microwave irradiation on SWCNTs was their debundling.