Surface preparation of (110) oriented pure and Nb doped SrTiO3 single crystal substrates by microwave assisted hydrothermal method

•Realization of single termination along (110) orientation in pure and Nb doped SrTiO3 single crystal substrates.•Microwave assisted hydrothermal alkaline etching is a universal method to realize single termination in SrTiO3 (110).•Method is fast and does not need an ultra-high vacuum environment and long annealing time at high temperatures.•Singly-terminated surface is of interest in the growth of layered multifunctional oxide heterostructures on SrTiO3 (110)

We present a simple and fast microwave-assisted hydrothermal etching process for (110) oriented pure and Nb doped SrTiO3 substrates. An annealing in oxygen atmosphere at 1000 °C after the etching in both deionized water and ammonia solution resulted in single-terminated surface for pure SrTiO3. In the case of niobium-doped substrates, such a surface could be realized only through etching in ammonia solution and subsequent annealing at 1100 °C. Observed step height of a/√ 2 nm in the topography by atomic force microscopy suggests [(SrTiO)4 +] or (O2)4 − termination. This realization of conducting/non-conducting, singly-terminated surface is of interest in the growth of layered multifunctional oxide heterostructures on SrTiO3 (110).