• 文献标题:   Wrinkling of graphene because of the thermal expansion mismatch between graphene and copper
  • 文献类型:   Article
  • 作  者:   OGURTANI OT, SENYILDIZ D, BUKE GC
  • 作者关键词:   atomic force microscopy, copper, graphene, strain, thermal stresse, wrinkling
  • 出版物名称:   SURFACE INTERFACE ANALYSIS
  • ISSN:   0142-2421 EI 1096-9918
  • 通讯作者地址:   TOBB ETU
  • 被引频次:   1
  • DOI:   10.1002/sia.6423
  • 出版年:   2018

▎ 摘  要

Well-defined bundles of wrinkles are observed on the graphene-covered copper by using atomic force microscopy after chemical vapor deposition process. Their numerical analyses are performed by employing a set of formula deduced from classical elasticity theory of bent thin films with clamped boundary conditions. Here they are imposed by the banks of trenches associated with the reconstructed copper substrate surfaces, which suppress lateral movements of graphene monolayers and induce local biaxial stress. The wrinkling wavelength (lambda) and amplitude (A) are both measured experimentally (lambda = 100-160 nm and A = 2.5-3 nm) and calculated numerically (lambda = 167 nm and A = 3.0 nm) and found to be in good agreement. Wrinkle formation is attributed to the nonhydrostatic compression stresses induced on the graphene by the linear thermal expansion coefficient difference between graphene and copper during cooling. These mismatch stresses, which are varying strongly with the temperature, create temperature-dependent wrinkling wave formation that decreases in wavelength and increases in amplitude upon cooling below the crossover temperature of 1233 K, at which both values of linear thermal expansion coefficient are equal.