Influence of substrate on nucleation and growth of vertical graphene nanosheets

• Published in: Applied surface science 2015-09, Vol.349, p.576-581
• Main Authors: Ghosh, Subrata, Ganesan, K., Polaki, S.R., Mathews, Tom, Dhara, Sandip, Kamruddin, M., Tyagi, A.K.
• Format: Article
• Language: English
• Subjects: Defects; Density; ECR-CVD; Graphene; Morphology; Nanostructure; Nucleation; Platinum; Quartz; Raman spectroscopy; SEM; Vertical graphene nanosheets
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2015.05.038

•Substrate dependent growth of vertical graphene nanosheets (VGNs) is studied under ECR-CVD.•Substrate properties like surface energy and thermal conductivity plays the major role in differential growth of VGNs.•Formation of a-C and pentagon–heptagon structure at early stage nucleation dictates the morphology and structural quality.•A phenomenological model is demonstrated to understand substrate dependent growth. The present study reports the role of substrate on nucleation and growth of vertical graphene nanosheets (VGNs) under electron cyclotron resonance chemical vapor deposition (ECR-CVD). The VGNs are grown on Pt, Ni, Au, Cu, Si(100), Si(111), SiO2 and quartz substrates simultaneously. The morphology of VGNs is found to vary significantly with substrate. VGNs on Pt have the highest aerial density of vertical sheets while quartz have the lowest. The structural defects in VGNs vary with substrate as evidenced from Raman spectroscopy. The observation of defect related Raman bands such as D″ and D* at 1150 and 1500cm−1, respectively revealed the existence of pentagon–heptagon rings or carbon onions in VGNs. Formation of such defects at early stage of nucleation dictates the growth mechanism and hence the morphology. A phenomenological four-stage model is discussed, to substantiate the nucleation and growth mechanism of VGNs on different substrates, by evoking substrate–plasma interaction during growth.