Long lifetime of free excitons in ZnO tetrapod structures

摘要

Time-resolved photoluminescence u0001PLu0002 is employed to characterize optical quality of ZnOntetrapods. PL decay of free excitons u0001FEu0002 is concluded to contain two components with timenconstants of 1 and 14 ns at room temperature. The fast PL decay is attributed to nonradiativenrecombination whereas the slow decay is suggested to mainly represent FE radiative lifetime, basednon correlation between thermally induced increases in the PL linewidth and FE lifetimes. The resultsnunderline superior optical quality of the tetrapods as the decay time of the slow PL component isncomparable to the longest lifetimes reported to date for ZnO. © 2010 American Institute of Physics.