Spatially resolved surface-related exciton polariton dynamics in a single ZnO tetrapod.

The band-edge emission lifetime in a single ZnO tetrapod is studied by using the time-resolved confocal micro-photoluminescence (TR- μ PL) spectroscopic technique at room temperature. By performing μ PL and TR- μ PL mapping along the tapered arm of tetrapod, we observe whispering gallery mode (WGM) polaritons and find that the predominant radiative lifetime of exciton polaritons decreases linearly with increasing the surface-to-volume ratio of the sample. This behavior is ascribed to the surface electric field induced enhancement of the radiative decay rate of the exciton-like polaritons coupling with LO phonons. [ABSTRACT FROM AUTHOR]