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(0)X) 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(0)X 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(0)X-longitudinal optical (LO) phonon coupling is also acquired by measuring TRPL spectra of the first-order LO phonon-assisted FX and D(0)X 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.