Realization of single-termination SrTiO_3 (100) surfaces by a microwave-induced hydrothermal process

摘要

A microwave-induced hydrothermal etching of SrTiO_3 (100) single crystal surfaces in deionized water and subsequent annealing in oxygen atmosphere results in single-terminated and atomically flat terraces for pure and niobium-doped substrates as confirmed through one unit-cell step height and uniform phase by atomic force microscopy. This process that requires 3min of moderate microwave radiation completely avoids the use of hydrofluoric acid (HF) and related point defects due to fluorine in the crystal surface. The advantages of a safe, inexpensive, and environmentally neutral process hold promise to replace the existing standard protocol for substrate preparation based on buffered HF.