Abstract:
Development in nanotechnology leads to discovering new nanostructured materials with complex atoms or molecules and extraordinary properties. The major challenge in the structure-property correlation of nanostructured materials is the characterization of three-dimensional structures at the atomic scale. The modern state-of-the-art transmission electron microscopes can resolve structures at an atomic scale. Still, conventional tilt series tomography faces challenges in 3D reconstruction at atomic resolution due to missing wedge and high electron dose. Low dose tomography technique named as inline 3D holography reconstructs the 3D structure at atomic resolution using exit wave reconstruction and electron channeling theory. Already reported experimental nanostructures were prepared using the focused ion beam (FIB) technique; therefore nanostructure doesn’t need any support for imaging. But other nanostructured materials such as nanoparticles cannot be prepared using FIB. They are prepared on a commercially available Cu grid with amorphous carbon film. Recently it was reported that the amorphous carbon support induces strain artefact within the nanoparticle. There is no report of the influence of amorphous carbon film on the 3D reconstruction of nanostructures using inline 3D holography. Therefore our first objective is to study the impact of the amorphous carbon support on the tomographic reconstruction of nanoparticles. 3D reconstruction of complex nanostructures is essential for better understanding the arrangement of atoms and their role in defining material properties. Our second objective is to implement inline 3D holography to reconstruct the 3D structure of non-cubic InN quantum dot (QD) at a low electron dose. At last, the atomically resolved nanocuboid structure of high energy {111} faceted anatase TiO2 sized below 20 nm is revealed. This work expands the application of the inline 3D holography technique for the 3D reconstruction of complex nanostructures.