Improved photoluminescence and lasing behaviors in ZnO microstructures assisted by surface plasmon resonant of Au nanoparticles
Tsai-Ching Chiang1*, Cing-Yu Chiu1, Tsen-Fang Dai1, Yu-Ju Hung2, Hsu-Cheng Hsu1,3
1Photonics, National Cheng Kung University, Tainan, Taiwan
2Photonics, National Sun Yat-sen University, Kaohsiung, Taiwan
3Advanced Optoelectronic Technology Center, National Cheng Kung University, Tainan, Taiwan
* presenting author:江采晴,
An improvement of the ultraviolet (UV) band-edge emission and lasing threshold of the ZnO microstructures can be achieved by the SP effect of Au nanoparticles. By decorated Au nanoparticles, the near-band-edge emission can be enhanced by 11 fold and the defect-related emission is completely suppressed due to the electron transfer between the conduction band and defect levels through the localized surface plasmon resonance. In Ni nano-thin film/ZnO microstructures, the defect-related emission can be reduced. However, in contrast, the band-edge emission cannot be enhanced due to band-edge emission because Ni is a lossy material in UV range. In the lasing emission, the lasing threshold of ZnO microstructures with Au coating can be reduced by 50 %. This result suggest that Au nanoparticles can effectively enhance lasing characteristic by turning down the lasing threshold, which is attributed to the resonance coupling between the surface plasmon and the optical transition in ZnO. In addition, surface plasmon resonance can effectively improve the ZnO emission behaviors by Au nanoparticles. It’s may play another important role in the random lasing mechanism.

Keywords: Zinc oxide, random lasing, surface plasmons