Excitonic formation inhibition in GaInAs/InP Fe doped quantum wells

摘要

Fe-doped InGaAs/InP multiple quantum wells for ultrafast saturable absorption applications are measured by pump-probe experiments. Iron-doping allows us to control sample photoresponse time from nanosecond range to a value as short as 0.45 ps for an iron concentration of 6 x 10~(18) cm~(-3). The Differential Transmission Ratio (DTR) of samples with increasing Fe-doping at moderate optical excitation levels is studied. We observe a DTR decrease below 1ps which we attribute to an inhibition of exciton formation at high iron doping level when the exciton Bohr radius is comparable to the mean distance between Fe related traps.