Ultraviolet lasing in Zn-rich ZnO microspheres fabricated by laser ablation.

Zinc (Zn) surface plasmons (SPs) have been widely reported for their impressive performance in improving the optical properties of semiconductors. Zn is an effective metal with SPs response in the ultraviolet region, but the disadvantage of strong metal activity limits the application mentioned above. Here, in order to ensure the stability of metal Zn, ZnO/Zn microspheres were synthesized by an one-step laser ablation method to distribute Zn nanoparticles simultaneously on both inner and outer surfaces of ZnO microspheres. Lasing performance enhancement and a lower threshold were obtained in the composite which originates from the coupling between Zn SPs and the excitation light source. Accompanied by the lasing emission measurements, the coupling mechanism was explained through time-resolved photoluminescence spectroscopy (TRPL) for the samples by rapid annealing in situ. This work displays the results of lasing enhancement and the physical process of Zn SPs resonance in the ZnO/Zn microsphere.