Kinetics of interfacial charges in hybrid GaAs/oligothiophene semiconducting heterojunctions

The authors report on pump-probe measurements in a hybrid heterostructure consisting of a modified oligothiophene layer deposited over a GaAs substrate. Upon photoexcitation of the bilayer with 100 fs, a new photoinduced absorption band (PA(2)) appeared being attributed to oligothiophene cations arising from exciton diffusion and dissociation at the hybrid inorganic/organic interface. An exciton diffusion length in the organic layer of approximately 3.4 nm was estimated. (c) 2007 American Institute of Physics.