Precise Analysis of Graphene by Low Voltage TEM Technique

Youngji Cho1, Jun-Mo Yang1, Do Van Lam2, Seung-Mo Lee2, Jae-Hyun Kim2

1National Nanofab Center

2Korea Institute of Machinery & Materials

Graphene, a single atomic monolayer of sp2-bonded hexagonal carbon with extraordinary mechanical, electronic, and optical properties, has become a subject of great interest in materials science. Thus it is expected that graphene will be applied in various industry. TEM technique is getting a lot of attention as an attractive method for analyzing both morphology and structural properties of graphene. However the damages by electron beam energy make it difficult to observe graphene because conventional TEM is operated at an accelerating voltage up to 200 kV. For successful TEM analysis of graphene, it needs to observe at the low acceleration voltage less than 100 kV which can minimize the damages. In this study, we analyzed graphene using low voltage TEM at 80 kV. To analyze structural properties such as grain boundary and orientation, dark-field TEM (DF-TEM), high-resolution TEM images and electron diffraction patterns (DP) were observed. Also, we performed diffraction pattern simulation, and the simulation results were matched experimental ones. It is demonstrate that low voltage TEM technique is useful method to analyze the morphology and structure of graphene.

Keywords: Graphene, Low voltage TEM, Dark-field imaging, Electron diffraction patterns