ULTRAFAST REFLECTIVITY CHANGES IN PHOTOEXCITED GAAS SCHOTTKY DIODES

The transient reflectivity of GaAs Schottky diodes is measured by femt osecond time resolved pump-probe experiments. The measured reflectivit y for photon energies near the band gap reveals transient quasioscilla tory behavior with frequencies up to 5.5 THz. The changes of the refle ctivity are due to extremely fast changes of the carrier density withi n the depletion layer, We interpret the observed oscillatory signal as coherent plasma oscillations, Ensemble Monte Carlo simulations for th e scenario agree well with the observed plasmon frequencies. (C) 1996 American Institute of Physics.