Raman spectra (shown in Figure  2d) were performed to detect and characterize the graphene layers in the surface of the glass wires with the different growth times (10 and 20 min). Both of the Raman spectra present typical characteristics of selleck screening library graphene layers: obvious D, G, and 2D bands at PRIMA-1MET nmr approximately 1,340, approximately 1,588 and approximately 2,700 cm-1. For the Raman spectrum of the sample grown for 10 min, The I 2D/I G intensity ratio is approximately 1.1, and the full width at half maximum (FWHM) of 2D band is approximately 45 cm-1, which represents one to two layers of graphene film [28]. For the Raman spectrum of the sample grown

for 20 min, the I 2D/I G intensity ratio is approximately 0.5, and the full width at half maximum (FWHM) of 2D band is approximately 55 cm-1, which represents three to five layers of graphene film [28]. Compared with the Raman spectrum of the monolayer graphene [1], the 2D band of the multilayer graphene is broader and can be fitted into multipeaks, which can be explained by the double-resonance

theory: the electronic band YH25448 in vitro structure and electron-phonon interactions change with the number of the graphene layers [29]. In particular, the observed small D band intensity as compared to the G band intensity indicated low levels of defects or local disorder in our MLG films. Figure 2 SEM images before and after deposition and Raman spectra of the 3D graphene/glass fibers. (a) (b) The SEM images before and after deposition of the graphene for 20 min on the glass fiber membrane surface. (c) SEM image of the 3D graphene/glass fibers with the different diameter. (d) Raman spectra of Tyrosine-protein kinase BLK the 3D graphene/glass fibers deposited for 10 and 20 min. It is possible to investigate the state of the graphene by transferring it to a small holey copper grid using TEM. The HR-TEM image (shown in Figure  3) was conducted on the sample to identify the number of the graphene layer. The edge-on image of graphene

in Figure  3 indicates the thickness of the prepared graphene is three to five layers and the measured intergraphene spacing is approximately 0.34 nm, which is consistent with the previous report [28]. In addition, the electron diffraction (ED) pattern on the multilayer graphene film (the inset of Figure  3) reveals a hexagonal pattern, confirming the threefold symmetry of the arrangement of carbon atoms in graphene. These TEM results show direct evidence that multilayer graphene film is directly fabricated on the glass fibers. Figure 3 HR-TEM image of the graphene layers deposited for 20 min. The inset shows the ED pattern of the multi-layer graphene film. In our experiment, the lower-temperature (600°C) growth is necessary due to the lower melting point of the glass fiber, which can be obtained by the revised CVD system with the two-heating reactor. The mechanism of synthesis of core-shell graphene/glass fiber structures by using such revised CVD system has been discussed here.