Nanoscale epitaxial growth control of oxide thin films by laser molecular beam epitaxy—towards oxide nanoelectronics

摘要

The nanoscale growth control of oxide thin films, such as ferroelectric and magnetic materials, were explored by a novel technique based on nanoscale substrate engineering as well as atomic layer control via laser molecular beam epitaxy (laser-MBE). Atomic-scale analysis of the terminating layer of perovskite oxide films was performed by in situ coaxial impact-collision ion scattering spectroscopy. The novel heteroepitaxies that could be attained were: (1) the termination-regulated molecular layer-by-layer epitaxy of BaTiO₃ and La_0.7Sr_0.3MnO₃ thin films and (2) the step-decoration epitaxy resulting in the nanowire or nanodot structures of magnetic oxides such as (Mn, Zn) ferrite on ultrasmooth sapphire substrates with straight atomic steps.