Direct resonant coupling of Al surface plasmon for ultraviolet photoluminescence enhancement of ZnO microrods.

More than 170-fold ultraviolet emission enhancement was obtained from the hexagonal ZnO microrods synthesized by a simple vapor-phase transport process and decorated by Al nanoparticles (NPs). Based on the stable and transient photoluminescence (PL) spectra of the ZnO microrods sputtered with Al NPs for different times, the underlying mechanism was deduced and can be attributed to the metal surface plasmon resonance (SPR) coupling with ZnO. Interestingly, with increasing of the sputtering time, the ratio of the band gap emission to the defect-related emission was increased from 0.1 to 42.7. Our results demonstrated that ZnO microrods decorated with Al NPs shed light on developing stable and high-efficiency excitonic optoelectronic devices such as light-emitting diodes and lasers.