Phonon scattering of excitons and biexcitons in ZnO

Phonon scattering of excitation and biexcitons in ZnO was measured using femtosecond four-wave mixing as functions of excitation wavelength, excitation power, and temperature. The exciton-phonon and the biexciton-phonon coupling coefficients were also determined. It was found that the biexciton-acoustic phonon interaction coefficient is as large as β ^bi _ac≈53 μeV/K. It was suggested that for A excitons, the interaction coefficient with the acoustic phonon scattering is β ^ex _opt≈8.4 μeV/K and the coupling constant with the low frequency E ₂ mode phonon is β ^ex _opt≈14 meV.