ULTRAFAST CARRIER DYNAMICS AT A METAL-SEMICONDUCTOR INTERFACE STUDIED BY FEMTOSECOND LUMINESCENCE SPECTROSCOPY

The ultrafast carrier dynamics in the high electric field at an Au-GaAs interface has been studied both experimentally, using a subpicosecond photoluminescence correlation technique, and theoretically by a Monte Carlo simulation. The photoluminescence decay time has been found to increase drastically with input power, ranging from a few picoseconds at low excitation to a considerably higher value (10-20 ps) at high excitation. From the Monte Carlo calculations it has been found that at high excitation the applied field collapses almost instantaneously. Even for a recharging time constant of 1 ps, which corresponds to the estimated device RC time, a drastic slowing down of the carrier sweep-out has been found, in almost quantitative agreement with the experimental findings.