Atomic force microscopy has been used to measure the surface profile of a periodic array of 10-nanometer (nm)-diameter holes fabricated by fast-atom beam milling of a smooth graphite surface in which a 3.5-nm-thick titanium oxide screen was used as a mask. The nanostructured titanium oxide mask was itself derived from a protein crystal template. Pattern transfer from the biological crystal to the metal oxide film and finally to the graphite substrate was accomplished entirely by parallel processing.

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Droplets of uncoated molten Si (0.4–0.8 mm diameter) have been undercooled 250 °C. Ge droplets of similar size have been undercooled 280 °C in a B2O3 flux. The observed nucleation onset temperatures of both Si and Ge droplets are at or below the predicted amorphous phase melting temperatures Ta1. The solidified structures were polycrystalline. The nucleation frequency I, calculated from the Si data (2×104/cm3 s at 240±20 °C undercooling), should be an upper limit of the homogeneous nucleation frequency of the crystal phase, since we did not establish that nucleation was homogeneous in our experiments. However, this limiting I for Si indicates that homogeneous nucleation of crystal would not become appreciable in laser pulsing experiments until the liquid Si is undercooled to well below Ta1.

We have examined the structure of S-layers isolated from Sulfolobus acidocaldarius using atomic force microscopy (AFM) and transmission electron microscopy (TEM). From the AFM images, we were able to directly observe individual dimers of the crystal, defects in the crystal structure, and twin boundaries. We have identified two types of boundaries, one defined by a mirror plane and the other by a glide plane. This work shows that twin boundaries are highly structured regions that are directly related to the organization of units within each crystal domain. Projection maps from TEM images have shown that there are significant differences in the final average maps has allowed us to relate high magnification views obtained by AFM to the relatively high resolution information obtained by electron microscopy and image processing.

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