Published online by Cambridge University Press: 21 February 2011
Preliminary experimental high resolution micrographs have been obtained for a Au thin film containing a [001], Σ=5 (θ=36.5 °) twist boundary. Other twist boundary cases such as the [001], Σ=13 (θ= 22.6°) and [111] low angle (˜3°) have also been fabricated. In order to assess whether the atomistic boundary structure is being imaged, extensive computer simulations of the Σ=5 bicrystal images have also been undertaken. Structurally, several contributions to the scattering must be considered which include: both upper and lower surface layers, bulk contributions above and below the interface and the relaxed interfacial structure at the composite film midplane. The effect of specimen orientation on image features is also evaluated for dynamical diffraction conditions. Likewise, the types of image features which arise by including bulk lattice reflections or alternately including only the reflections arising from the interface and surfaces will be discussed. Several schemes for analyzing twist boundary structures flat-on or near flat-on will be presented for a wide range of microscope conditions for a 400 kV microscope.