The direct observation of atomic surface structure and inclined planar defects in Au(111) films

Abstract

With a high resolution electron microscope it is possible to image directly the atomic surface lattice of vapor-deposited Au(111) films. The contrast of the surface atoms can be either black or white relative to the background which is characteristic of close-packed planes of atoms in the stacking sequence ABCABC.... An analysis of these images was performed using multislice dynamical diffraction computations of 256 × 256 = 65 536 reciprocal space points and subsequent image simulations. The effects of top and bottom surface roughness, different termination layers and the contrast compared with single-atom imaging are considered. The identification of atomic structure detail at incoherent double-position boundaries in these (111) films was also achieved. Surface layer terminations, variations in the choice of every third matching plane and the possibility that twinning planes produce boundaries with jogs were investigated. Multislice computer programs were designed to calculate the diffraction effects from these inclined boundaries using two-dimensional fast Fourier transform and shift techniques of the projected potential. This is the first time that inclined planar defects have been analyzed in this manner. © 1982.