The evolution of properties with deposition time of vertical graphene nanosheets produced by microwave plasma-enhanced chemical vapor deposition

Abstract In our studies, the vertical graphene nanosheets (VGN) of various heights and densities were grown on fused silica substrates by microwave plasma-enhanced chemical vapor deposition technique at different growth durations from 20 to 140 min to follow the evolution of VGN properties on the deposition time. The feedstock of the working gases and applied microwave power was kept constant focusing solely on the influence of the deposition duration. The properties and quality of VGN samples were explored by methods of scanning electron microscopy, atomic force microscopy, Raman scattering spectroscopy, and transient absorption spectroscopy (TAS). A clear correlation between the TAS results and the defectiveness and disorder of VGN layers defined by Raman scattering spectroscopy illustrates that the TAS technique can be efficiently used to describe the quality of graphene nanostructures. Increasing the deposition duration optimal growth conditions were determined ensuring the highest quality of the graphene while further increase resulted in deposits of different carbon allotropes.