Photoluminescence of atomic layer deposited ZrO2:Dy3Â + thin films

Atomic layer deposition based on alternate cycling of ZrCl4, Dy(thd)3 and H2O as precursors was applied for preparation of nanocrystalline ZrO2:Dy thin films. Photoluminescence (PL) properties of Dy3 + in the ZrO2 films were studied at several laser excitations. Substantial activation of Dy3 + PL required thermal treatment at 900 °C. As a result of annealing, thinner (~ 80 nm) films with higher Dy content retained relatively high amount of tetragonal phase and remained crack-free. In thicker (~ 140 nm) films, considerable amount of monoclinic phase was formed and a peculiar microscale cracking pattern was developed along with phase segregation. It is demonstrated that the crystal structure of ZrO2 significantly influences the Dy3 + emission spectrum and, at least for ZrO2-type matrices, Dy3 + is an excellent luminescent microprobe in comparison with micro-Raman scattering. A Förster-like PL decay profile allowed a conclusion that the self-quenching due to cross-relaxation between Dy3 + ions had a marked impact on emission intensity.