Formation dynamics of excitons and temporal behaviors of fano resonance due to the exciton-impurity-phonon configuration interaction in ZnO

Formation dynamics of free and neutral donor bound excitons (FX and D 0X) in a high quality ZnO single crystal are studied by means of time-resolved photoluminescence (TRPL) at various temperatures. At low-temperatures, FX and D 0X formation times are determined to be ∼5 and ∼10 ps, respectively, by fitting the rise process with the Boltzmann sigmoidal function. Temporal information of FX- and D 0X-longitudinal optical (LO) phonon coupling is also acquired by measuring TRPL spectra of the first-order LO phonon-assisted FX and D 0X transitions. In particular, interesting time evolution of luminescence intensity in the Fano resonance region due to the configuration interaction of exciton-impurity-phonon is explored. © 2011 American Chemical Society