Phase-shifting electron holography for atomic image reconstruction

Phase-shifting electron holography was used to reconstruct the object-wave function of high-spatial-frequency specimens of HgCdTe, and the requirements for precise measurements were investigated. Fresnel fringes due to the electrostatic biprism caused serious calculation errors during the phase-shifting reconstruction. Uniform interference fringes, obtained by adjusting the biprism voltage to cancel out the Fresnel fringes, were needed to minimize these errors. High-resolution holograms of a HgCdTe single crystal were recorded with coarse interference fringes and a high visibility of 65% and then used to reconstruct the atomic-scale object wave. Although the spatial resolution (0.25 nm) of the transmission electron microscope was worse than the separation (0.16 nm) between Hg (or Cd) and Te columns, the crystal polarity was determined from the aberration-corrected object wave.