Photoluminescence and energy transfer processes in rare earth ion doped oxide thin films with substrate heating

Tm-Er codoped amorphous aluminum oxide thin films were prepared by pulsed laser deposition. Broadband photoluminescence in the wavelength region of 1400-1700 nm comprised of two emissions at around 1532 and 1620 nm was observed. PL performance was investigated as a function of the substrate-heating temperature. Possible energy transfer processes involved in the heat treatment were discussed and nonradiative decay rates were evaluated, by comparing the inverse of measured lifetimes with the calculated radiative decay rates. Our results suggest that Tm-Er codoped Al₂O₃ thin film might be potential candidate as broadband light sources and amplifiers.