Sub-monolayer nucleation and growth of complex oxides at high supersaturation and rapid flux modulation

Abstract

We report on the unusual nanoscale kinetics of the layer-by-layer deposition of complex oxide heterostructures composed of a unit-cell thick correlated metal LaNiO3 and dielectric LaAlO3. The ultrathin multilayers demonstrate extremely good crystallinity and surface morphology maintained over the large number of layers, as confirmed by combination of AFM, RHEED, and synchrotron x-ray diffraction. To elucidate the physics behind the growth, the temperature of the substrate and the deposition rate are varied over a wide range and the results are treated in the framework of a two-layer model. The results demonstrate that, in addition to temperature and vapor supersaturation, modulated flux can be employed as a powerful kinetic handle for the fine-tuned manipulation of sub-monolayer growth regimes of multicomponent materials.