Understanding the growth mechanism of vertically aligned graphene and control of its wettability

Single-step growth of graphene and graphene-based nanostructures by plasma-enhanced chemical vapor deposition

“…Zhang et al [74] performed post fabrication argon sputtering of VG-GNs to increase the surface defect content as determined by Raman and x-ray photoelectron spectroscopies. These argon-sputtered VG-GNs with higher defect concentrations were found to be more hydrophilic than as grown VG-GNs, suggesting that the hydrophilicity of VG-GNs can be manipulated via defect engineering.…”

“…XPS characterizations can provide critical information for the chemical purity and/or heteroatom doping content of the VG-GNs [93]. Additionally, high resolution spectra of the carbon 1s peak can indicate the relative content of sp 2 and sp 3 hybridized carbon, which is an indicator of the defect concentration and the quality of VG-GNs [74]. Ganeson et al [175] performed a detailed comparison of XPS and Raman Page 14 of 30 AUTHOR SUBMITTED MANUSCRIPT -NANO-119760 .R1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 A c c e p t e d M a n u s c r i p t spectroscopy measurements of VG-GNs and suggested that the two techniques in tandem could provide information about the type of defects present.…”

“…Other useful characterization methods include ultraviolet photoelectron spectroscopy (UPS) for measuring the work function of VG-GNs [176,177], which provides useful information about the doping level of the graphene nanostructures; wettability studies, where the contact angle of a water droplet on the VG-GN sample is determined [72,74]; surface area measurements via nitrogen adsorption Brunauer-Emmett-Teller (BET) method [178]; and electrical transport measurements that determine the resistivity, carrier concentration and electron mobility [61,179,180]. In addition, certain application-specific characterizations, such as the cyclic voltammetry measurements, are carried out to evaluate the performance for energy storage applications.…”

Analysis of plasma-grown carbon oxide and reduced-carbon-oxide nanowalls

“…There are sp 3 , sp 2 , and p bonds owing to the CNW mechanism. 14,18,19 In Fig. 6(b), which shows the C1s peak of the CONW, the C-O and C]O bonds (the functional group) can be seen as having increased compared to those in Fig.…”

Adhesion-Increased Carbon Nanowalls for the Electrodes of Energy Storage Systems

“…When a CNW grows on a substrate, it first forms a buffer layer (or a few graphene layers) and then partially develops defects, causing graphene to grow vertically [6][7][8]14,31]. Therefore, it becomes a lamellar structure, and when analyzed via XPS, which receives and analyzes the energy at 1-10 nm from the surface, the energy from the flat part (graphene layer) between the walls can be seen on the substrate where the CNW was grown [31]. As such, Figure 4b, which presents the XPS survey results and the C1s peak of CNW/ITO without surface and structural variation even after ultrasonic cleaning, shows the CNW sample grown on ITO, with some In3d and Sn3d peaks.…”