Femtosecond Visible Pump Mid-IR Probe Study on the Effects of Surface Treatments on Ultrafast Photogenerated Carrier Dynamics in n-GaAs(100)Crystals

摘要

The femtosecond visible pump mid-IR probe technique was employed to investigate photogenerated carrier dynamics in n-GaAs(100)crystals subjected to various surface treatments in a time domain of picoseconds-several tens of picoseconds.Pt- or Ru-treatment significantly accelerated the carrier recombination as a result of the introduction of surface states.The recombination rate was also increased by Au-treatment but less significantly than that by the Pt- or Ru-treatment.The effect of sulfide treatment on the recombination dynamics seemed to be rather small,although it has been reported that the density of surface states is decreased by the sulfide treatment.