Decay dynamics of excitonic polarons in InAs/GaAs quantum dots

作者：Werner S^*; Reparaz J S; Wagner M R; Zimmer P; Ledentsov N N; Kabuss J; Dachner M R; Richter M; Knorr A; Thomsen C; Hoffmann A

来源：Journal of Applied Physics, 2011, 110(7): 074303.

DOI：10.1063/1.3639310

We present time-resolved studies of the exciton-phonon interaction in self-assembled InAs/GaAs quantum dots. Different scattering and luminescence processes were investigated by time-resolved spectroscopy exciting resonantly into the quantum dot's electronic structure. By studying the characteristic decay times of the ground state and of several phonon-assisted recombinations we were able to distinguish a resonant Raman process from a phonon-assisted photoluminescence process which are always simultaneously present and can interfere with each other. While lifetimes under 30 ps were observed for the coherent Raman process, the incoherent phonon-assisted recombination exhibited typical lifetimes of around 1 ns independently of the excitation energy. We conclude that under resonant excitation the dominant radiative recombination process in this system always involves an electronic state of the ground state of the quantum dot's electronic structure. Combining temperature-dependent and time-resolved measurements we show that a weak phonon-bottleneck is present in the low temperature regime (< 130 K), while it disappears for higher temperatures.

• 出版日期2011-10-1