Dynamics of photoexcited carriers in GaInAs/GaAs quantum dots

We present photocurrent and time-resolved photoluminescence investigations of AlGaAs/GaInAs/GaAs structures containing GaInAs/GaAs self-assembled quan tum dots. The high electrical field in those devices significantly influenc es carrier dynamics. The photocurrent spectra show a double peak with maxim a at 1.40 and 1.47 eV (at 80 K). These maxima are clue to the GaInAs wettin g layer (higher) and the quantum dots (lower). The photoluminescence spectr a comprise weak excitonic luminescence from GaAs at 1.504 eV (at 80 K) and stronger and broad emission from the Ga0.4In0.6As quantum dots. At 300 K, t he quantum dots emission has a lifetime of 1.1 ns and has a maximum at an e nergy of 1.38 eV. By analysis of both experiments, we can separate the infl uence of different radiative and nonradiative recombination processes. So, the tunneling rate: r(T) = 0.5 ns(-1) and the radiative recombination rate in the quantum dots: r(RQD) = 0.4 ns(-1) have been determined. The high tun neling probability (due to the influence of the built-in electric field) re veals that the tunneling effect is important for the recombination and tran sport processes in our structures.