Temperature effect on the electronic structure of Nb：SrTiO3（100） surface

The effect of temperature on the electronic structure of Nb-doped SrTiO3（100） surface is investigated by highresolution synchrotron radiation photoemission spectroscopy.According to the x-ray photoemission spectroscopy（XPS）results,at an annealing temperature of less than 700 ℃,the adsorbed carbon and hydroxyl on the STO surface could be removed,to expose the fresh intrinsic surface with a constant ratio of Ti/O.It is obvious that the STO would be doped by Ca^＋ impurities of bulks and O vacancies in the surface after annealing at 920 ℃ for one hour.