Synthesis and characterization of carbon nanowalls on different substrates by radio frequency plasma enhanced chemical vapor deposition

• Published in: Carbon (New York) 2014-06, Vol.72, p.372-380
• Main Authors: Davami, Keivan, Shaygan, Mehrdad, Kheirabi, Nazli, Zhao, Jiong, Kovalenko, Daria A., Rümmeli, Mark H., Opitz, Joerg, Cuniberti, Gianaurelio, Lee, Jeong-Soo, Meyyappan, M.
• Format: Article
• Language: English
• Subjects: Carbon; Chemical vapor deposition (including plasma-enhanced cvd, mocvd, etc.); Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Ferromagnetism; Fullerenes and related materials; diamonds, graphite; Graphene; Magnetization; Materials science; Methods of deposition of films and coatings; film growth and epitaxy; Nanostructure; Physics; Plasma enhanced chemical vapor deposition; Radio frequencies; Specific materials; Walls
• ISSN: 0008-6223; 1873-3891
• DOI: 10.1016/j.carbon.2014.02.025

A radio frequency plasma enhanced chemical vapor deposition system was used for the successful growth of thin vertical carbon nanowalls, also known as vertical graphene, on various substrates. Transmission electron microscopy studies confirmed the presence of vertical graphene walls, which are tapered, typically consisting of 10 layers at the base tapering off to 2 or 3 layers at the top. The sides of the walls are facetted at quantized angles of 30° and the facetted sides are usually seamless. Growth occurs at the top open edge which is not facetted. Hydrogen induced etching allows for nucleation of branch walls apparently involving a carbon onion-like structure at the root base. Characterization by a superconducting quantum interference device showed magnetic hysteresis loops and weak ferromagnetic responses from the samples at room temperature and below. Temperature dependence of the magnetization revealed a magnetic phase transition around T=50K highlighting the coexistence of antiferromagnetic interactions as well as ferromagnetic order.