By combining information from low-resolution images and diffraction patterns, sub-atomic-resolution diffractive imaging of quantum dots can be achieved
Diffractive imaging, carried out by monitoring the passage of X-rays and electrons through a material, could potentially yield information about the three-dimensional structure of single nanoparticles on the atomic scale. However, sub-ångström resolution is not possible because weak coherent scattering cannot be detected by conventional diffraction imaging procedures. Now, Jian Zuo and colleagues1 at the University of Illinois at Urbana-Champaign report sub-ångström-resolution diffractive imaging of cadmium sulphide (CdS) quantum dots by integrating information from a low-resolution 'image' with the diffraction pattern generated by the passage of electrons through the sample.
The electron diffraction patterns were recorded inside a transmission electron microscope using an electron beam with a diameter of 40 nm and an energy of 200 keV. Notably, the CdS dots were supported by graphene or carbon nanotube substrates — which have a lattice mismatch with CdS — to minimize background diffraction signals and overlapping of diffraction peaks. Using this method, a four-fold improvement in the resolution of the CdS diffraction image was achieved, resolving the smallest separation between the Cd and S atomic columns of 0.84 ångströms.
As low-resolution images can be obtained from various sources, this technique provides a general method for the high-resolution, three-dimensional imaging of individual nanoparticles.
References
Huang, W. J. et al. Sub-ångström-resolution diffractive imaging of single nanocrystals. Nature Phys. 10.1038/nphys1161 (2008).
Rights and permissions
About this article
Cite this article
Sandhu, A. Highs from lows. Nature Nanotech (2009). https://doi.org/10.1038/nnano.2009.3
Published:
DOI: https://doi.org/10.1038/nnano.2009.3