Ultrafast Charge Dynamics in Bulk Zinc Oxide under Intense Photoexcitation

The photo-induced charge dynamics of textbook wide-bandgap semiconductor ZnO have been investigated on the picosecond time-scale. We performed optical Pump-THz Probe experiments in order to measure dielectric constant material after high-fluence photo-excitation carriers. technique allows access both carrier lifetime and scattering rates, it provides direct intrinsic function changes upon excitation. A complex dynamic is unveiled pumping regime, where relaxation time hundreds picoseconds range increases with increasing Pump fluence, while onset photoconductivity takes place a few picoseconds. plasma frequency dependence fluence are discussed.