Plasmonic control of ZnO random lasing characteristics

We demonstrate that the emission wavelength and lasing threshold of the ZnO random laser are controlled by the surface plasmon effect of Ag nanoparticles. The addition of Ag nanoparticles causes surface plasmon resonance at the peak wavelength of the ZnO gain spectrum, thereby resulting in a shift in lasing wavelength toward shorter wavelengths and a decrease in threshold power. Such phenomena depend on the amount of Ag nanoparticles present, and they can be adequately explained by a theoretical model including the surface plasmon effect, namely, an enhancement of the light absorption and scattering strengths in a metal/semiconductor system.