The blue emission at 2.8？eV in strontium titanate: evidence for a radiative transition of self-trapped excitons from unbound states

ABSTRACT The origin of the blue emission in SrTiO3 has been investigated as a function of irradiation fluence, electronic excitation density, and temperature using a range of ion energies and masses. The emission clearly does not show correlation with the concentration of vacancies generated by irradiation but is greatly enhanced under heavy-ion irradiation. The intensity ratio of the 2.8 and 2.5？eV bands is independent of fluence at all temperatures, but it increases with excitation rate. The 2.8？eV emission is proposed to correspond to a transition from conduction band states to the ground state level of the self-trapped exciton center. GRAPHICAL ABSTRACT The blue emission at 2.8？eV in strontium titanate: evidence for a radiative transition of self-trapped excitons from unbound states All authors M. L. Crespillo , J. T. Graham, F. Agulló-López, Y. Zhang & W. J. Weber https://doi.org/10.1080/21663831.2019.1604444 Published online: 17 April 2019 Display full size IMPACT STATEMENT A novel mechanism attributes the origin of the intriguing blue band in SrTiO3 to a non-localized transition of the self-trapped exciton center from conduction band states to the ground level