Investigating the mechanism of time dependent evolution of vertical graphene nanowalls

This work presents a time dependent multistage growth model for vertical graphene nanowalls (VGN). Factors mediating growth of VGN in both vertical and spatial direction at different stages were discussed. VGN films were deposited on Si (100) substrate using Radio Frequency Plasma-Enhanced Chemical Vapor Deposition technique by increasing the deposition time systematically for 15 min, 30 min, 60 min, 120 min, and 240 min, respectively. Scanning electron microscopy was carried out in both planar and cross section view to confirm the growth of VGN and quantification of its height. Atomic force microscopy was used to characterize the spatial growth of VGN. Raman scattering and in-plane GIXRD measurements were carried out to characterize the microstructure of VGN, which unveils that the strain relaxation and defects annihilation followed by increase in average crystallite size plays crucial role. Eventually, a schematic diagram was presented for time dependent evolution of VGN at different stages.