Rheed studies of a-axis oriented DyBa_2Cu_3O_7 films grown by all-mbe

摘要

Real-time, in-situ surface monitoring by reflection high-energy electron diffraction (RHEED) has been the key enabling ocmponent of atomic-layer-by-layer molecular beam epitaxy (ALL-MBE) of complex oxides. RHEED patterns contain information on crystallographic arrangements and long range order on the surface, this can be made quantitative with help of numerical simulations. The dynamics of RHEED patterns and intensities reveal a variety of phenomena such as nucleation and dissolution of secondary-phase precipitates, switching between growth modes (layer-by-layer, step-flow), surface phase transitions (surface reconstruction, roughening, and even phase transitions induced by the electron beam itself), etc. Some of these phenomena are illustrated here, using as a case study our recent growth of atomically smooth a-axis oriented DyBa_2Cu_3O_7 films.