Phase-contrast Imaging by Annularly Arrayed Detectors in Hollow-cone Illumination STEM

Abstract

We have developed a method that is able to reveal the phase shifts of electron waves using an annular aperture and annularly arrayed detectors in scanning transmission electron microscopy (STEM). The reconstructed phase image using this method will have the potential for the observation of thick crystalline specimens within the kinematical approximation, since this technique has an expanded focal depth, which reduces the blurring. In this paper, we will introduce details of this method and the STEM system, and recent results.