CRYSTALLOGRAPHIC STRUCTURE AND DEFECTS IN EPITAXIAL BISMUTH-FILMS GROWN ON MICA

Atomic force microscopy is used to image the surface relief of epitaxi al Bi films grown on mica substrates. Monatomic terrace steps are read ily resolved, which provide detailed information on crystal growth and defect structures. The films grow from the coalescence of isolated th ree-dimensional islands, however, each island grows layer-by-layer. Th e islands are triangular in shape and when they coalesce to form a con tinuous film, their structures are either in-phase, and consequently l arge crystallites are formed, or they are out-of-phase and defect stru ctures are formed. The most common defects observed are twinning and s tacking faults. Images showing the microscopic details of stacking fau lts, twinning, and grain boundaries are observed as a result of island s coalescing to form a continuous film.