Nano-Physical Characterization of Chemical Vapor Deposition-Grown Monolayer Graphene for High Performance Electrode: Raman, Surface-Enhanced Raman Spectroscopy, and Electrostatic Force Microscopy Studies

Abstract

To achieve high-quality chemical vapor deposition of monolayer graphene electrodes (CVD-MG), appropriate characterization at each fabrication step is essential. In this article, (1) Raman spectroscopy/microscopy are employed to unravel the contact effect between the CVD-MG and Cu foil in suspended/supported formation. (2) The Surface-Enhanced Raman spectroscopy (SERS) system is described, unveiling the presence of a z-directional radial breathing-like mode (RBLM) around 150 cm−1, which matches the Raman shift of the radial breathing mode (RBM) from single-walled carbon nanotubes (SWCNTs) around 150 cm−1. This result indicates the CVD-MG located between the Au NPs and Au film is not flat but comprises heterogeneous protrusions of some domains along the z-axis. Consequently, the degree of carrier mobility can be influenced, as the protruding domains result in lower carrier mobility due to flexural phonon–electron scattering. A strongly enhanced G-peak domain, ascribed to the presence of scrolled graphene nanoribbons (sGNRs), was observed, and there remains the possibility for the fabrication of sGNRs as sources of open bandgap devices. (3) Electrostatic force microscopy (EFM) is used for the measurement of surface charge distribution of graphene at the nanoscale and is crucial in substantiating the electrical performance of CVD-MG, which was influenced by the surface structure of the Cu foil. The ripple (RP) structures were determined using EFM correlated with Raman spectroscopy, exhibiting a higher tapping amplitude which was observed with structurally stable and hydrophobic RPs with a threading type than surrounding RPs. (4) To reduce the RP density and height, a plausible fabrication could be developed that controls the electrical properties of the CVD-MG by tuning the cooling rate.

Synthesis and Applications of Optical Materials

“…The N-CQDs were probed for metal ion detection in aqueous solutions and during bioimaging and displayed a Cr 3+ and Cu 2+ selectivity shift at a higher degree of -NH 2 functionalization, as well as HEK-293 cell nuclei marking. W.-H. Park reviewed the various characterization methods of chemical vapor deposition of monolayer graphene electrodes (CVD-MG), which are devised and developed for achieving a largescale, highly flexible, and transparent electrode [ 20 ].…”

Observation of domain‐selective defect effects from a CVD‐grown graphene monolayer sandwiched at individual nanoparticle‐on‐mirror plasmonic junctions

“…[11] Fang and co-workers previously examined the emission effect of photoexcited hot electrons from plasmonic metal nanostructure, which is still a challenging issue in the field of nanophotonics for solar harvesting, water splitting, photocatalysis, and a variety of optical sensing. [12] In this work, the investigation of spaced CVD-GM in NPoM for the locational relationship by loading individual Au nanoparticles (NPs) likewise seminanoindentation through the AFM topography with corresponding Raman image (and SERS spectral behaviors) is carried out and discovered the domain-dependent (the most outer/center domain) different defect types phenomena in the NPoM system [13][14][15][16][17][18][19][20][21][22][23][24] in terms of establishing the new defect domain-selective sensing platform. The individual NPoM plasmonic junction, composed of Au NP/CVD-GM /Au TF, can be precisely inspected by AFM, and the author can find out that the line profile of the most outer domain of NPoM shows near-two symmetrical deep pits, due to probably physical loading of Au NP onto the CVD-GM/Au TF.…”