LAUSR

Abstract The use of SrTiO3(001) substrates with single TiO2- or SrO-terminated surface is often required in order to grow high quality epitaxial thin films. Many surface preparation recipes can be found in the literature, based on different etching solutions (acid, neutral and basic pH) and combined with different annealing treatments. In this work, we compare three different methods usually used to obtain atomically flat TiO2-terminated SrTiO3 surfaces in which water, aqua regia (HCl-HNO3) and BHF (NH4F-HF) solutions are used as reactive agent. Atomic force microscopy measurements (recorded in topography, phase detection and Kelvin-probe force modes) show that using the BHF solution leads to a reliable selective dissolution of SrO on the substrate surface, thus allowing to efficiently obtain atomically flat single TiO2-terminated surfaces. The aging of the resulted surfaces as well as the possibility of layer-by-layer deposition atop is also discussed.