Unconventional photoluminescence effect of SrTiO3 thin film under UV-illumination

►We showed that SrTiO3 thin film exhibits anomalous behavior of PL intensity I(t) with UV-laser illumination. ►When the STO is under ultra-high vacuum condition, I(t) increases with time under UV-illumination. ►In contrast I(t) decreases when STO is exposed to O2 and N2 gas. ►We considered the rise of sample temperature as candidate of the I(t) change. ►We propose photo-catalysis effect on STO surface as possible scenario of the PL intensity change.