Study of the surface chemical state and structure of SrTiO3 (001) under elevated oxygen pressure

Abstract

Using ambient pressure X-ray photoelectron spectroscopy (AP-XPS) and low energy electron diffraction (LEED), surface states and structure of SrTiO3 (001) single crystal are investigated. AP-XP spectra shows that SrO1+x surface oxide was observed under oxygen pressure condition. Also, the binding energy of SrTiO3 spectra shifted toward lower energy as the oxygen pressure increased. The analysis of AP-XP spectra shows the reconstruction of surface electronic structure of SrTiO3 during oxygen thermal annealing condition. Although there is a slight difference in LEED intensity, the intensity pattern shows double domain c(6×2) structure after annealing under all pressure conditions. The fact that the identical existence of LEED pattern in both of the UHV environment and oxygen environment confirms the strong stability of SrO1+x oxide.