Ridge formation and removal via annealing in exfoliated graphene

Sang A. Han, In Sung Choi, Hyo Sub An, Hyunsoo Lee, Hyeon Deuk Yong, Sangwook Lee, Jongwan Jung, Nae Sung Lee, Yongho Seo

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


It is well known that graphene is a very promising material due to its excellent physical, chemical, and thermal properties. Previousl ly, ridges in g raphene on a substrate were found in epitaxial graphene on a SiC substrate. It was found in this study that ridges can be made on a graphene layer via mechanical exfoliation on a sapphire substrate, and that ridges can be created or removed through heating and cooling. Due to the difference of the thermal-expansion coefficients of the substrate and graphene, it can be said that thermal cycling causes compressive strain, which is released by forming ridges. Annealing was carried out in a vacuum chamber within the pressure range of 10 -3∼10 -6 Torr and at 900∼1100 °C. To analyze the shapes and mechanical properties of the ridges, Raman spectroscopy and AFM measurement were performed. It was found that the ridges can be extended by defect as a nucleation center, and the graphene layer can be folded along the preexisting ridge during heating and cooling.

Original languageEnglish
Pages (from-to)5949-5954
Number of pages6
JournalJournal of Nanoscience and Nanotechnology
Issue number7
StatePublished - Jul 2011


  • Annealing
  • Atomic Force Microscopy
  • Graphene
  • Graphite
  • Raman
  • Ridge


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