Evidence of photoinduced charge transfer in C60/GaAs(1 0 0) bilayers by pump–probe measurements

Hybrid interfaces in semiconductor heterostructures consisting of C60/GaAs bilayers have been investigated by means of ultrafast pump–probe spectroscopy. From previous results, the energy levels alignment at the interface shows no injection barrier for electrons from GaAs to C60. Measurements have been carried out in order to monitor photoinduced electron transfer across the interface. Upon selective excitation of the GaAs layer we observe photobleaching (PB) of C60 due to a decrease of C60 neutral molecules. We monitor the PB dynamics concluding that electron transfer proceeds in about 4 ps and then relaxes back to ground state in timescales beyond 100 ps.