Growth process and structures of carbon nanowalls by plasma-enhanced chemical vapor deposition

摘要

Carbon nanowalls (CNWs) were fabricated on Si substrate by a dc plasma-enhanced chemical vapor deposition. The morphology and structure of CNWs with various deposition times were examined by means of atomic force microscopy (AFM) and grazing incidence X-ray diffraction (GIXD). It is shown that CNWs are composed of the stacking of graphene layers which contain both turbostratic and non-turbostratic graphite. In the samples with 1-2 min deposition, the graphene layers parallel to the substrate surface are predominant. In the sample with 3 min deposition, the graphene layers perpendicular to the substrate are also appeared. Moreover, it should be noticed that not only the graphitic phase but also other crystalline ones are clearly observed in only this stage. The crystalline phases might be responsible for the change in the orientation of graphene layers, relative to the substrate. In the samples with deposition times of more than 4 min, the vertical graphene layers increase with increasing deposition time. Consequently, the vertical growth becomes predominant.