Focused ion beam directed self-assembly (Cu 2O on SrTiO 3 ): FIB pit and Cu 2O nanodot evolution

Abstract

A gallium focused ion beam has been used to create discrete pits on a SrTiO 3(100) surface with the idea that these pits will serve as the nucleation sites for subsequent Cu 2O nanodot growth. The concentration of gallium within these pits has been analysed using a high-resolution Auger system immediately after pit formation and also following wet chemical etching and thermal annealing of the surface. The geometry of the pits has been determined following etching and annealing using atomic force microscopy (AFM). Growth of Cu 2O nanodots on the patterned surfaces has been performed for different processing and Ga dose conditions. Growth of Cu 2O nanodots within the pits is the primary mode of dot formation. In several samples, dot growth within pits appears to occur by a two-step process with pits filling before initiation of a second, distinct phase of nanodot growth above the plane of the original SrTiO 3 surface.