Sr surface segregation and water cleaning for atomically controlled SrTiO 3 (0 0 1) substrates studied by photoemission spectroscopy

Abstract

The chemical properties and electronic structures of atomically flat SrTiO 3 (0 0 1) substrates with various surface treatments have been investigated by high-resolution synchrotron-radiation photoemission spectroscopy. We have found that an annealing process causes the segregation of Sr oxides at the TiO 2-terminated surface. We demonstrate that the use of water-cleaning process is effective as a removal technique for Sr oxides segregated on TiO 2-terminated surfaces with preserving the surface morphology and chemical bonding states of the topmost TiO 2-terminated surfaces.