Critical effects of substrate terraces and steps morphology on the growth mode of epitaxial SrRuO3 films

Abstract

We report on the controlled fabrication of the arrays of self-organized fingerlike nanostructures of SrRuO3 that form on SrTiO3(001). We show that the size (width and height) of the one-dimensional nanometric units can be tuned or suppressed by using appropriate substrate vicinality θv and surface termination. Critical effects on the fingers height are observed when θv is below an angle as small as ∼0.1°. The value of θv also determines if the final two-dimensional growth is by a step flow (θv=0.5°), by layer by layer (θv=0.04°), or by coexistence of both mechanisms (θv=0.1°). The fingers are suppressed when TiO2-terminated low-miscut substrates are used, as film nucleation takes place on the terraces and then substrate steps are not active as templates for the one-dimensional structure formation. These findings shall contribute to progress toward lateral nanostructuration of complex oxide surfaces.