Oxygen vacancies in SrTiO3

摘要

Oxygen vacancy clustering in SrTiO3-?? thin films has been investigated by electrical transport and photoemission spectroscopy. We deposited SrTiO3-?? thin films on LaAlO3(001) substrate at reducing oxygen ambients. The carrier density did not increase with decreasing the ambient oxygen pressure. Photoemission study shows multi valence state of Ti ion including Ti+2 which localized state. Those results are explained by electron localization via oxygen vacancy clustering.