Ultrafast Dynamics of Exciton–Exciton and Exciton–Longitudinal Optical-Phonon Scattering Processes in ZnO Epitaxial Thin Films
Time-resolved luminescence spectra due to the exciton–exciton collision process were measured in ZnO thin films under excitonic resonant and band-to-band excitations by the optical Kerr gate technique. The luminescence due to the exciton–exciton collision process instantaneously emerges under excitonic resonant excitation, while it emerges with a delay of a few picoseconds under band-to-band excitation. The time delay observed indicates that, first, exciton–longitudinal optical (LO)-phonon scattering occurs and, then, the exciton–exciton collision process takes place after the completion of the thermal cooling of excitons through the cascade emission of multiple LO-phonons. The time delay is quantitatively evaluated by a simple calculation based on the exciton–LO-phonon scattering process.
- Japanese journal of applied physics. Pt. 1, Regular papers & short notes
Japanese journal of applied physics. Pt. 1, Regular papers & short notes 45(9A), 6961-6963, 2006-09-15
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physics