Experimental Characterization of Fabricated (310) and (210) Symmetrical Tilt High-Angle Grain Boundaries in Bicrystalline Copper Thin Films Using NaCl Substrates

A novel sintering method of bridging the two mechanically polished and oriented single-crystals together face-to-face in a non- environmental controlled atmosphere to fabricate the bicrystal substrate of NaCl of macroscopic thickness, with a common zone axis and having planarity over large areas, has been developed. Epitaxial [001] bicrystalline thin face-centered cubic (fcc) metal film of surface-reactive metal-containing tilt grain boundary across the interface is first grown in high vacuum directly by flash deposition on initially fabricated [001] oriented bicrystalline substrate of NaCl. The [001] tilt boundary, thus produced, and is examined by electron microscopy to characterize grain boundary morphology and structure. The findings of some preliminary investigations are then presented. A distinct atomic structure is observed for 310 and 210 inclination. Both HAADF-STEM and Diffraction images reveal that such fabricated high-angle grain boundary accommodates minor deviations from the exact high coincidence density σ=5 misorientation. The potential use of the present technique is extended to produce a wide variety of homophase bicrystals, containing grain boundaries at the midplane, normal to any crystallographic surface without the necessity of a separate bonding operation.