Luminescence properties of Er3+ doped zirconia thin films and ZrO2/Er2O3 nanolaminates grown by atomic layer deposition

Atomic layer deposited (ALD) ZrO2 (zirconia) thin films doped with Er3+ ions by ion implantation as well as ZrO2/Er2O3 nanolaminates were investigated at wide 5-300 K temperature range using cathodoluminescence (CL) and photoluminescence (PL) spectroscopy under wide range of excitation energies 6-120 eV. In the studied ALD films main emissions due to self-trapped excitons and defect centers were revealed in UV-visible (VIS) region with the excitation bands in the host absorption. In nanolaminates luminescence processes are influenced by their structure and composition. In films with the lower Er3+ ion content, typical 4f luminescence of Er3+ ions were identified being excited through energy transfer from host to doping ions. The luminescence data shows that in contrast to a few hundred nm thick ALD films, the excitonic band near 5.3-5.4 eV are absent in the excitation spectra of nanolaminates with a typical layer thickness of 5 nm, which do not facilitate exciton formation because of limited spatial regularity.