Enhanced ultraviolet lasing from europium-doped zinc oxide nanocrystals

Europium (Eu)-doped zinc oxide (ZnO) nanocrystals are prepared by the sol–gel method. Compared with undoped ZnO nanocrystals, Eu-doped ZnO nanocrystals have enhanced ultraviolet (UV) lasing and reduced threshold at room temperature. The UV lasing properties of both the doped and the undoped samples were studied by the time-resolved and power-dependent photoluminescence (PL) experiments. The enhancement of UV lasing is due to the significantly reduced singly ionized oxygen vacancies with Eu doping, which is confirmed by both the PL spectra and the X-ray photoelectron spectra. It indicates that high-efficiency and low-threshold UV lasing sources can be fabricated from Eu-doped ZnO nanocrystals.