ELECTRON-BEAM-INDUCED TRANSFORMATIONS OF GOLD PARTICLES EPITAXIALLY GROWN ON MGO MICROCUBES

Different epitaxial orientations (100), (110) and (111) of gold particles crystallized on clean MgO cubes were observed in HRTEM. During the electron irradiation, terraces (presumably MgO) are formed on the surfaces of the cubes, preferentially near the gold particles and at their interface with the substrate. During the growth of the terraces, the particles in (110) or (111) orientations rotate on the substrate and stay in the so-called "quasimolten state" until they get the stable (100) orientation. The origin of the growth of the terraces is attributed to the formation of Mg(OH)2 on the surface of the MgO during the air exposure, which dehydrates in MgO in the electron beam.