In situ control of graphene ripples and strain in the electron microscope

• Published in: NPJ 2D materials and applications 2018-08, Vol.2 (1), Article 25
• Main Authors: Ludacka, U., Monazam, M. R. A., Rentenberger, C., Friedrich, M., Stefanelli, U., Meyer, J. C., Kotakoski, J.
• Format: Article
• Language: English
• Subjects: 639/301/119/544; 639/301/357/918/1053; Chemistry and Materials Science; Diffraction patterns; Electron microscopes; Graphene; Materials Science; Microscopy; Morphology; Nanotechnology; Ripples; Surfaces and Interfaces; Tensile strain; Thin Films; Two dimensional materials
• ISSN: 2397-7132; 2397-7132
• DOI: 10.1038/s41699-018-0069-z

We demonstrate control over the three-dimensional (3D) structure of suspended 2D materials in a transmission electron microscope. The shape of our graphene samples is measured from the diffraction patterns recorded at different sample tilts while applying tensile strain on the sample carrier. The changes in the shape of the pattern and in individual diffraction spots allow us to analyze both corrugations and strain in the lattice. Due to the significant effect of ripples and strain on the properties of 2D materials, our results may lead to new ways for their engineering for applications. Microscopy: transmission electron microscope allows control of graphene 3D morphology Corrugations in a free-standing graphene membrane can be measured in situ and tuned in an electron microscope chamber. A team led by Jani Kotakoski at the University of Vienna used transmission electron microscopy to control the 3D shape of suspended graphene samples. The diffraction patterns recorded from the samples were found to change when applying tensile strain, allowing insight to the evolution of out-of-plane undulations in the graphene lattice. Uniaxial pull was found to first flatten the corrugations in the direction parallel to the pulling force, after which the flattened graphene could be strained by continuous pulling. As the 3D ripples in graphene strongly affect its thermal and electronic properties, such direct control over its out-of-plane morphology may lead to graphene structures with tailored functionalities.