Research interest in low dimensional materials has expanded immensely in the last decade. The fascinating properties of nanotubes, graphene and transition metal dichalcogenides (TMDCs) has pushed this research toward applications in composites, (opto)-electronics and photovoltaics.
Seeing and understanding the physical and chemical structure of these nanostructures is a vital aspect of this growing research area. Using rotational tomography on low dimensional TMDCs, we reveal additional points of view that are not routine in transmission electron microscopy (TEM). Bright field TEM highlights the non-uniformity of tungsten disulphide (WS2) nanotube tips, as well as revealing structural deformities in the nanotubes as a whole. Complimentary to this, we present high-angle annular dark field (HAADF) scanning TEM tomography, which provides clearer structural interpretation through fewer Bragg scattering events being detected. 2D nanosheets are also characterised via high resolution TEM tomography, allowing for a three dimensional view of a 2D object. As the sample is rotated, further lattice and thickness information is acquired.
Having these complimentary tomographic methods available for nanomaterial characterisation will help to improve the accuracy of interpretation and results. Often, 2D TEM images lead to assumptions about the nature of these materials. Tomography at high resolution will reveal more information on the shape and structure of the studied nanomaterials (e.g., ripples) in 3D.
Figures:
Figure 1: Bright field TEM (top series) and high-angle annular dark field STEM (bottom series) images of a WS2 nanotube cluster, rotated from -25 degrees to +25 degrees. The nanotube cap in the 25 degrees tilt image (arrowed), for example, is indeed a ‘hook’ (in the -25 degrees image), which would not be revealed in a 2D image.
To cite this abstract:
Eoghan O'Connell, Yina Guo, Robert Young, Florian Winkler, Beata Kardynal, Ursel Bangert; Seeing nanostructures from a new angle – tomography in a transmission electron microscope. The 16th European Microscopy Congress, Lyon, France. https://emc-proceedings.com/abstract/seeing-nanostructures-from-a-new-angle-tomography-in-a-transmission-electron-microscope/. Accessed: December 4, 2023« Back to The 16th European Microscopy Congress 2016
EMC Abstracts - https://emc-proceedings.com/abstract/seeing-nanostructures-from-a-new-angle-tomography-in-a-transmission-electron-microscope/