Prospects for 3D, nanometer-resolution imaging by confocal STEM

Confocal STEM is a new electron microscopy imaging mode. In a microscope with spherical aberration-corrected electron optics, it can produce three-dimensional (3D) images by optical sectioning. We have adapted the linear imaging theory of light confocal microscopy to confocal STEM and use it to suggest optimum imaging conditions for a confocal STEM limited by fifth-order spherical aberration. We predict that current or near-future microscopes will be able to produce 3D images with 1 nm vertical resolution and sub-angstrom ngstrom lateral resolution. Multislice simulations show that we will need to be cautious in interpreting these images, however, as they can be complicated by dynamical electron scattering. (c) 2006 Elsevier B.V. All rights reserved.